SEIT Research Report 2011_Final

Engineering and Information Technology Research Report 2011

Never Stand Still School of Engineering and Information Technology

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The School of Engineering and Information Technology is one of four Schools of the University of New South Wales located at the ADFA campus in Canberra. Research is a key focus for the School, and inspires our approach to teaching and other activities.


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“Once we accept our limits, we go beyond them” – Albert Einstein

Production:Editor: Dr Sreenatha Anavatti School of Engineering and Information Technology Design: Creative Media Unit

Cover image: Rotary UAV

Back cover image: Hypersonic Tunnel

1Engineering and Information Technology Research Report 2011

ForewordThe School of Engineering and Information Technology (SEIT) is one of the four schools of the University of New South Wales located at the Australian Defence Force Academy campus in Canberra. Outstanding research is a key focus for the School. This inspires our approach to teaching and other activities in the School. The School’s diverse research interests span our base disciplines and reach into a wide variety of application areas including space, control, cyber security, air-traffic management, complex imaging and many others.

The research funding to the School comes from various sources including the Australian Research Council, Centre of Excellence, Research Networks, the Department of Defence, Defence Science and Technology Organisation and the University of New South Wales along with other private organisations. The research output from the School has shown excellent growth with as many as nearly 350 publications included in the Higher Education Research Data Collection.

The School is encouraging quality research and healthy competition inside the School by innovative ideas like special awards for Excellence in Research Publications for Academics and Ph.D. scholars. The number of publications in highly ranked journals as well as high impact journals has increased considerably over the last few years.

A number of academics in the School received high recognitions in the last year enhancing the profile of the School significantly. Professor Ian Petersen was elected a fellow of the Australian Academy of Science and was awarded the prestigious Australian Research Council (ARC) Laureate Fellowship. Dr Sameer Alam was one of the ACT Young Tall Poppies of the year for being an outstanding young scientist.

The number and quality of Ph.D. scholars is increasing continuously indicating the involvement of the School in research training. The School has been able to attract quality students from various countries around the world, providing a dynamic work force.

This research report summarises the research achievements of the School’s community during the year 2011.

Prof Elanor Huntington Head of School

April 2012

2 Engineering and Information Technology Research Report 2011

Frequently Used Abbreviations ADFA Australian Defence Force Academy

ANSTO Australian Nuclear Science and Technology Organisation

ARC Australian Research Council

BUS School of Business

CRC Cooperative Research Centre

CSIRO Commonwealth Scientific and Industrial Research Organisation

DEST Department of Innovation, Industry, Science and Research

DEEWR Department of Education, Employment and Workplace Relations

DSARC Defence and Security Applications Research Centre

DSTO Defence Science and Technology Organisation

HASS School of Humanities and Social Sciences

NASA National Aeronautics and Space Administration

NICTA National Information and Computer Technology Australia

PEMS School of Physical, Environmental and Mathematical Sciences

RRTO Research and Research Training Office

SEIT School of Engineering and Information Technology

UNSW University of New South Wales

USAF United States Air Force


ContentsResearch Activities 4

Acoustics and Vibration 4Air Traffic Management 9Aviation Research 15Composite Materials and Structures 17Computational Intelligence 28Concrete Technology and Materials 32Control Theory and Control Applications 36Cyber Security 39Developmental Systems and Machine Learning 41Engineering in Medicine 44Maximum-Entropy Analyses of Flow Systems 46Geotechnical Engineering and Pavement Geotechnics 48High Frequency Engineering 53High-Speed Flows and Microfluidics 59Image Coding 67Imaging Through Turbulence 70Immiscible Contaminants in Natural Porous Media 73Operations Research and Optimisation 75Opto-Electronics 82Remote Sensing 88Social Networks Group 91Software Engineering 94Viable Systems Planning, Strategy and Architecture 95Systems Engineering 98Underwater Communications 100Unmanned Vehicles 103Virtual Environments & Simulation 107

Research Facilities 111

2011 SEIT Academics 115


Research Activities

» Acoustics and VibrationSEIT AcademicsProf. Joseph LaiDr Krishnakumar ShankarDr Sreenatha AnavattiDr Murat Tahtali A/Prof. Don Fraser

SEIT Postgraduate StudentsMr Nick Le’MarshallMr Sebastian OberstMs Zhi Fang ZhangMr Md. Younus Ali

SEIT Research StaffMrs Marion BurgessDr Sebastian Oberst

Other Collaborators

Bosch Chassis

Dr Antti PapinniemiDr Zhiye Zhao

CSIRO

Dr Theo A Evans

Oita University, Japan

Prof. Toru Otsuru

Sceintific Technology Pty Ltd

Dr Andrew Tirkel

University of Adelaide

Mr Gerard Rankin

Universität der Bundeswehr München, Germany

Prof. Steffen Marburg

Research DescriptionResearch undertaken by the Acoustics and Vibration group spans a wide range of topics and includes environmental noise, occupational noise, machinery noise control, structural dynamics, vibration monitoring for non-destructive inspection and interdisciplinary areas that involve acoustics, vibration, materials and biology. Below are some current research projects which require the use of state-of-the-art acoustics and vibration instrumentation and numerical modelling techniques such as the finite element method, boundary element method and nonlinear time series analysis.

Active noise control headphones and awarenessThis project is undertaken in collaboration with Dr Brett Moelsworth from School of Aviation at UNSW, Kensington. The main aim of the project is to examine the effect of noise cancelling technology (e.g., headphones) on concurrent task performance within an aviation environment. The investigations are undertaken within the laboratory with a simulation of the noise present in an aircraft cabin. The effect of the use of noise cancelling headphones by passengers on their ability to understand audio information, such as a safety message, as would be presented during the preparation for a commercial flight, is being investigated. This work is being extended to the effect of the use of such headphones on situational awareness.


Vibration and Acoustic Analysis of the Role of Nonlinearity in Disc Brake Squeal Disc brake squeal is a major source of customer dissatisfaction. The prediction of disc brake squeal propensity remains difficult despite significant progress made in the last two decades towards understanding its nature. A full brake system (Figure 1) is difficult to model exactly with regard to boundary contact conditions and material properties. Most of the numerical analysis of brake squeal is based on linear methods that have found some success in guiding the development of brakes in industry. One popular approach is the complex eigenvalue analysis using finite element models to predict unstable vibration modes. However, the complex eigenvalue analysis may over-predict or under-predict the number of unstable vibration modes and not all predicted unstable vibration modes will result in squeal. Therefore, extensive brake testing in noise dynamometers is required in order to ensure that the noise performance of brakes is acceptable. Although the analysis of brake squeal propensity is primarily based on linear approaches, it has been recognised that the operation of a brake contains a number of nonlinearities such as the excitation through the friction contact between the disc and pad, material properties, and operating conditions.

Our research has shown that (i) some brake squeal is caused by nonlinearity; (ii) brake squeal test data obtained in a brake noise dynamometer display features typical of deterministic chaos (Figure 2); and (iii) the noise performance of brake systems can be ranked by statistical analysis and nonlinear time series analysis of brake test data. In order to study the role of nonlinearity in disc brake squeal, the dynamics of an analytical forced 2 dof friction oscillator sliding in a plane with a constant friction coefficient is examined (Figure 3). Results in Figure 4 show that friction coupling nonlinearity can produce weak chaotic behaviour and support the findings of in-plane pad mode instabilities observed in a numerical pad-on-disc model. By using models of simplified brake systems and energy analysis, we have shown that instabilities associated with pad modes have significant potential to cause brake squeal although they are not detected by complex eigenvalue analysis to be unstable. The challenge would be to develop a method to exploit nonlinearity for more reliable prediction of brake squeal propensity.

Figure 1: Model of a one piston, floating calliper brake system with ventilated brake disc.


Figure 2: Attractor re-constructed from time series of brake squeal test data: (a) limit cycle, (b) torus, (c) choatic attractor

Figure 3: A forced 2 dof friction oscillator sliding on a the moving x-y plane.

Figure 4: (a) Time series of the position vector; (b) phase-space plots with Poincare section (plane A), maximal Lyapunov exponent and Kaplan-Yorke dimension; (c) power spectal density estimates.


Discovering how termites use vibratons to make foraging decisionsTermites are pests affecting one third of Australian homes. The annual cost of treatment and damage repair is over $20 billions worldwide. Despite being blind, termites with poorly developed anatomical defences possess remarkable abilities for survival against predators: infestations in houses are often only discovered when an apparently intact timber object collapses. Our recent research demonstrate for the first time that termites use vibrations to assess food quantity and quality and to avoid competitors by eavesdropping.

Considering that termites have a relatively simple nervous system with the entire cerebral ganglia of most termites occupying a volume of the order of 0.1 mm3, their abilities to use vibrations to make foraging decisions are remarkable feats. Yet, little is known about how termites make foraging decisions based on vibrations. We are studying the key features in vibration signals produced by termites to unlock the secrets of their foraging behaviour.

Effect of Millmeter Waves on Termite BehaviourA 24 GHz termite detector that has been successful in detecting termite movement through walls and floors was developed by Scientific Technology, and commercialized by Termatrac©. Apart from thermal effects, little is known about the effects that Termatrac© emissions have on the termites it senses. However, theoretical and experimental investigation of the interactions of millimeter and sub-millimeter waves with living things has a rich and varied history. This offers the intriguing possibility of termite provocation or control, using suitable emissions.

Figure 5 shows a typical set up to simulate termites travelling to and from their nest via mud tubes. The “nest” with or without vermiculite is on the left, the food (timber block) is on the right and the termites (workers and soldiers) in the central dish were exposed to 1 W of power at 24 GHz out of a pyramidal horn antenna directly above the dish. The thermal image in Figure 6 shows that the test worker termites (approx 12 mm) moved freely into and out of the beam and took turns in “basking” under the horn achieving a maximum temperature of 31°C which is within their thermal comfort zone and preferable to the ambient temperature of 22ºC. We have shown that 12 mm long termites exhibit resonant absorption near 25 GHz.

When termites were exposed to 1.3W at 28.24 GHz, individual termites were heated to 42°C. In order to entice termites into the beam, a dead termite was placed in the centre. This resulted in some termites venturing into the beam to investigate. These termites became distressed, and presumably sent distress signals to others, who followed, resulting in a huddle. This huddle proved suicidal, as shown in Figure 7, where the peak temperature exceeded 55ºC. Termites lack internal thermal regulation and lose most of their heat by radiation. The latter is proportional to ST4, where S is the surface area and T is temperature in ºK. By huddling, termites reduce their effective radiating surface area and increase the heat exchange between neighbours by radiation. This accounts for the extra 13ºC rise in the huddle. Suicidal huddling behaviour was also observed in termites “trying” to cross a water barrier, and it was also speculated that such huddles were also due to individuals in distress (who fell into the water) attracting a crowd of other victims. Such social behaviour for termites under distress have implications for termite control.

Figure 5: Schematic of Alarm Experiment.


Scanning Laser VibrometryThe school recently acquired a Scanning Laster Vibrometer (PSV-400) which measures velocity of vibrating objects using a laser and works on the princliple of doppler shift. The PSV-400 offers a highly accurate, quick and sensitive method of non-contact vibration measurement over a two dimensional surface using a motorized scanning head controlled by the computer. It comes with sophisticated modal analysis software that allows data to be displayed both in time domain and frequency domain, provides frequency response functions, mode shapes and so on.

Currently there are a number research projects using the Scanning Laster Vibrometer being undertaken in the school, including structural health monitoring of composite panels with delaminations and vibration monitoring of mechanically fastened and bonded joints. The school is also involved in collaborative research with researchers at the ANU and University of Tasmania studying the vibration characteristics of violins made from Tasmanian timber.

Figure 6: Worker Termite basking under the horn. Figure 7: Death Huddle

Figure 1: Examples of two modes of vibration for a plate of a violin


» Air Traffic ManagementSEIT AcademicsDr Sameer AlamProf. Hussein AbbassDr Chris LokanDr William Murray MountMr. Jiangjun TangDr Deborah Cherie Tucek

SEIT Postgraduate StudentsMr. Md. Murad HossainMr. Nizami JafarovMr. Van Viet PhamMs. Wenjing Zhao

Funding Agencies and Sources

Australian Research Council Airservices Australia Eurocontrol Experimental Centre, France Thales Australia

Research DescriptionAir transportation is a large, complex, and integrated network of systems, procedures, and infrastructure with a primary goal of safely expediting the air traffic flow. Present day air traffic systems are reaching their operational limits and accommodating future air traffic growth is a challenging task for air traffic service providers and airlines. Due to the structured and centralized nature of the system, it may not scale to meet demand. Therefore there is an urgent need to investigate and develop new methodologies and procedures by which the air transportation system can meet the future challenges from safety, capacity, environment and human factors perspective.

The ATM research group at UNSW Canberra is a multi-disciplinary research team that aims to develop methods for next generation air transportation concepts and systems which are robust in the face of increasing demands and external uncertainties. The research group has designed and developed practical, implementable algorithms and models backed by sound methodologies that aim to balance air traffic demand and airspace capacity while addressing safety, capacity, environment and human factors concerns. Our research will enable safe, efficient, robust, and green air transportation.

CAPACITY

Discovering Delay Patterns in Arrival Traffic with Dynamic Continuous Descent Approaches using Co-evolutionary Computational Red TeamingThe gradual introduction of advanced ATM procedures such as Continuous Descent Approaches (CDA) creates a challenge when balancing the capacity-demand of arrival traffic in the presence of constrained ground (runway, taxiway, gate) resources. Part of the challenge is to understand the interdependency between spatial-temporal distribution of arrival traffic (traffic distribution) and the dynamics of ground resources. We [Alam, Zhao, Tang, Lokan and Abbass] used the Computational Red Teaming (CRT) Framework to identify patterns in arrival traffic and ground events that lead to delays in dynamic CDA scenarios. The scenarios represent the interaction of ground events with traffic distributions. The search engine in CRT relies on co-evolutionary search, with the reciprocal interaction of traffic distributions and ground events evolving to identify bottlenecks in the system. With each interaction a variety of metrics are recorded which are then data mined to identify patterns that lead to delays. Results identified scenarios whereby delays become seriously significant. For example, for a model of the Sydney domestic terminal area in a dynamic CDA scenario, flights arriving from the South-East direction with an average inter-arrival time of 53 sec can cause significant delays if runway 16L is impacted by a ground event. A paper on this topic was awarded the best paper at the 9th US-Europe ATM R&D Seminar, Berlin, Germany, 2011


A multi-objective approach for Dynamic Airspace Sectorization using agent based and geometric modelsA key limitation when accommodating the continuing air traffic growth is the fixed airspace structure including sector boundaries. The geometry of sectors has stayed relatively constant despite the fact that route structures and demand have changed dramatically over the past decade. Dynamic Airspace Sectorization is a concept where the airspace is redesigned dynamically to accommodate changing traffic demands. Literature suffers from several operational drawbacks, and their computational complexity increases fast as the airspace size and traffic volume increase. We [Tang, Alam, Lokan and Abbass] evaluate and identify the gaps in existing 3D sectorization methods, and propose an improved Agent Based Model (iABM) to address these gaps. We also propose three additional models using KD-Tree, Bisection and Voronoi Diagrams in 3D, to partition the airspace to satisfy the convexity constraint and reduce computational cost. We then augment these methods with a multi-objective optimization approach that uses four objectives: minimizing the variance of controller workload across the sectors, maximizing the average sector flight time, and minimizing the distance between sector boundaries and the traffic flow crossing points. Experimental results show that iABM has the best performance on workload balancing, but it is restrictive when it comes to the convexity constraint. Bisection- and Voronoi Diagram-based models perform worse than iABM on workload balancing but better on average sector flight time, and they can satisfy the convexity constraint. The KD-tree-based model has a lower computational cost, but with a poor performance on the given objectives.

Co-evolutionary Simulation of airport ground movements and Terminal area traffic.

Examples of airspace sectors (Minimum Standard Deviation of workload) generated by 4 airspace sectorization models


ENVIRONMENT

A Multi-Aircraft Dynamic Continuous Descent Approach Methodology for Low Noise and Emission GuidanceContinuous Descent Approaches (CDAs) can significantly reduce fuel burn and noise impact by keeping arriving aircraft at their cruise altitude for longer and then having a continuous descent at near idle thrust with no level flight segments. The CDA procedures are fixed routes that are vertically optimized. With the changing traffic conditions and variable noise abatement rules, the benefits of CDA are not yet fully realized. We [Alam, Nguyen, Lokan, Ellejmi, Kirby and Abbass] proposed a methodology to generate aircraft-specific dynamic CDA routes that are both laterally and vertically optimized for noise, emission and fuel. The methodology involves discretizing the terminal airspace into concentric cylinders with artificial waypoints and uses enumeration and elimination (based on aircraft performance envelope) from one waypoint to another to identify all the possible routes.

From the resulting set of possible CDA routes, routes are identified that represent the best trade-off on the given objectives. The dynamic CDA algorithm is implemented in an air traffic simulator for Sydney Terminal Area. Dynamic CDA approach as compared to a typical CDA shows a reduction of 14.96% in noise, 11.6% reduction in NOx emission and 1.5% reduction in fuel burn. We also investigate the throughput capacity of transition airspace for multiple flights performing CDA operation for different traffic distributions. The methodology incorporates a delay algorithm which uses the flight’s estimated time of arrival at the Intermediate Approach Fix which allocates a conflict free CDA route by searching through possible routes. A paper based on this research was awarded the best paper at 29th AIAA/IEEE Digital Avionics Systems Conf., Salt Lake City USA 2010.

Figure: Fuel & Noise Trade-off Trajectories in a Continuous Descent Scenario


SAFETY

What Can Make an Airspace Unsafe? Characterizing Collision Risk using Multi-Objective OptimizationWith the continued growth in Air Traffic, researchers are investigating innovative ways to increase airspace capacity while maintaining safety. A key safety indicator for an airspace is its Collision Risk estimate, which is compared against a Target Level of Safety (TLS) to provide a quantitative basis for judg ing the safety of operations in an airspace. However this quantitative value does not give an insight into the overall collision risk picture for an airspace, and how the risk changes given the interaction of a multitude of factors such as sector/traffic characteristics and controllers actions for flow management.

In this paper, we propose an evolutionary framework with multi-objective optimization to evolve collision risk of air traffic scenarios. We [Alam, Aldis, Barry, Lokan, Butcher and Abbass] attempt to identify, through evolutionary mechanism, the minimal controller actions that can lead to higher collision risks, thereby identifying the contributing factors to collision risk. Experiments were conducted in a high-fidelity air traffic simulation environment, with an integrated collision risk model. Results indicate that “risk-free” traffic scenarios having collision risk below TLS can become ”risk-prone” by minimal controller actions, with Climb and Turn manoeuvrers contributing significantly to increased collision risk.

Analysis of the Australian Airport Network: A Complex Network ApproachAs for all means of transportation, the relationship between origin and destination results in a complex network of routes, which can then be complemented with information associated with the routes themselves, for instance, frequency, traffic load and distance. The theory of complex networks provides a framework for investigating the dynamics on the resulting network structure. In this paper, we investigate the structure and robustness of the Australian Airport Network (AAN) which represents Australia’s civil domestic airport infrastructure as a complex network. We [Hossain, Alam and Abbass] are investigating the indices of degree distribution, characteristics path length, clustering coefficient and centrality measure as well as the correlation between them.

Traffic & Sector Features effecting Aircraft Collision Risk.


Evaluating Ground-Air Network Vulnerability in an Integrated Terminal Maneuvering Area using Co-evolutionary Computational Red TeamingThe inherent complexity of terminal maneuvering area (TMA) necessitates a system level analysis to understand the total system dynamics and its vulnerability. The performance of advanced air traffic control (ATC) procedures, such as dynamic Continuous Descent Approaches (CDA), may not be appropriately assessed without considering the complex interactions among other parts of the environment in which it operates. This paper considers a TMA system which integrates the arrival and departure operations and combines air- and ground- side resources; thereby assists in understanding its vulnerability and evaluating advanced ATC concepts in this environment. We [Zhao, Alam and Abbass] proposed a methodology using Computational Red Teaming (CRT) framework to identify ground-air network bottlenecks by exploring areas of vulnerability in the integrated TMA. The search engine in CRT relies on co-evolutionary search which evolves reciprocal interaction of traffic distributions and ground events (including runways, taxiways and gates). As such, these interactions are considered from the perspective of identifying inefficiencies, with the integration of arrival and departure operations. By evaluating these interactions, we are able to identify inefficiencies or “improvement opportunities” in the implementation of future ATM concepts and, thereby, understand major bottlenecks which cause system inefficiencies. For instance, for a model based on the Sydney Kingsford-Smith Airport’s domestic terminal area in a dynamic CDA scenario, taxiway B can cause significant delays if it is impacted by a ground event. Another example identifies taxiways as a critical airport component with interactions between arrivals and departures affecting the airport’s throughput capacity.

HUMAN FACTORS

Towards a Code of Best Practice for Evaluating Air Traffic control InterfacesThe quality of computer interfaces in transportation command and control centres is vital to safe and smooth operations. Air Traffic Control (ATC) is probably the most dynamic area in transportation where a large amount of information is presented to the air traffic controller within a short timeframe. Future Air Traffic Interfaces (ATI) are on the horizon with more information and added levels of sophistication. Safety is becoming a default constraint in current systems and evaluating the usability of these interfaces has been seen traditionally as crucial for ensuring high operational safety standards. To this end, a strong business case for evaluating the usability of interfaces necessarily requires a full-scale justification of the usability study and its associated cost. The benefits of performing such an evaluation also need to be communicated to decision makers in terms of economic values and gains. It is at this point that the field of operational analysis intersects with human factor research. We [Abbass, Mount, Tueck and Pinheiro] proposed a methodology for conducting usability studies for ATI. The methodology has been designed to connect higher-level organisational objectives with low-level usability metrics. The methodology will be presented towards establishing a code of best practice for the design and conduct of usability studies in this domain. While the results can be generalised to other transportation command and control interfaces, this paper focuses on ATC because this code of best practice is tailored towards ATC functions.

Ground arrival network for Sydney Airport

An example of a scenario design. The x-axis represent time, the y-axis represents block-events, while each box in the figure represents corresponding time-span an event type will take within a scenario.


Cognitive, Ergonomic and Workflow Metrics of Advanced Air Traffic Control InterfacesIn this study, we [Abbass, Mount and Tueck] designed metrics to compare and evaluate future air traffic control interfaces (FATCI) for Thales. Our work provided a multi-dimensional picture of different factors that can be used to evaluate FATCI. Experiments with Air Traffic Controllers were conducted at Thales Centre of Excellence in Melbourne. The work demonstrated the robustness of the methodology which can scale from evaluating a function or component within an interface to a system-level evaluation between two different systems. The objectivity of the metrics provided an unbiased evaluation.

Automatic Data Collection Tools for Air Traffic Human Factor Experiments Human factors experiments represent a significant and expensive exercise, especially in safety critical domains such as Air Traffic Control. In these domains, gaining access to the user is not easy and every access to a user, is an opportunity to collect the right data where mistakes are detrimental and costly. Moreover, there are many actions and dynamics happening simultaneously within the experimental environment.

We [Bui, Jafarov and Abbass] are working on a set of tools that can help in capturing data automatically in an Air Traffic environment. We developed a tagging system that can help an analyst to tag events through a touch screen. We also developed a sophisticated voice-control system for communicating and recording voice on multiple channels to mimic the expensive hardware communication systems that exist within an air traffic control centre.

The Automatic Tagging System in use for our experiments at the Thales Centre of Excellence


» Aviation ResearchSEIT AcademicsMs. Sue BurdekinMr. Martin CopelandMajor Heath PrattA/Prof Andrew Neely

Research DescriptionThe Aviation Group within the School of Engineering and Information Technology conducts research into a range of aviation safety topics including: pilot behavioural issues; training and evaluation; design and development; ergonomics, and aspects of the human/machine interface. The School has an Aviation Safety Studio which contains a multi-engine flight simulator and two rotary aircraft simulators, all of which are utilized for teaching and research purposes.

HUMAN FACTORSMission Operations Safety Audit (MOSA) research was initially designed as an experimental study, conducted in an F/A-18 Hornet simulator, to determine whether military pilots could accurately self-report, immediately after the ‘flight’ (mission), on their operational performance across a predetermined selection of behavioural categories designed in conjunction with subject matter experts. To further test the MOSA methodology, this time in a civil multi-crewed operational environment, a second study was carried out, ‘in the field’, with the cooperation of a low cost carrier in Europe. The aim of the MOSA research was to validate behavioural self-reported data from professional pilots, so that management could have confidence in this safety-critical information, and feed it back into the training continuum. In doing so, a safety loop could be established in a cost effective, operationally specific and timely program of data collection. Both the military and the civil airline pilot studies found that professional pilots were able to effectively self-report on their own performance across a range of operationally tailored, predetermined categories of behaviour.

Recently, the MOSA methodology was tested in another operational environment and national culture; that of a regional airline operating turbo prop aircraft between island destinations in the Indian Ocean. The MOSA protocols were influenced by the previous MOSA studies, but, once again, they were customized by airline subject matter experts to reflect categories of behaviour that were relevant to their national and organisational culture, and to that specific operational environment. Confidential self-reported in-flight performance data from Captains and First Officers, all of whom had volunteered for the study, were compared to ratings from a trained observer (researcher) during forty one flight sectors. To validate the data, a series of company specific safety related questions were posed to each participating crew.

The answers to these questions were compared to information that had been collected by the organisation utilizing other means including technical review meetings; pilot initiated, and mandatory occurrence reports, and company safety investigation reports. This study is on-going.

Figure 1: Aircraft type used in the MOSA regional airline study

Figure 2: Volunteer pilots during in-flight performance evaluation

Figure 3: One of the island airports involved in the study


Aircraft System Modeling Verification Using Ocular Behaviour Metrics Simulator developers are adopting advances in computer processing, graphics processing and image modeling to produce synthetic environments with unprecedented levels of fidelity. The availability of technology to support high fidelity simulators combined with the potential economic and safety benefits of simulation as a training medium has embedded simulation into the aviation training system. The aviation industry’s confidence and acceptance in the use of simulators as an effective training transfer medium has been consolidated by the assumption that high fidelity simulation equates to high training transfer. However, despite continuing advances in the fidelity of visual, cockpit layout and motion simulation (i.e. perceptual fidelity), training system developers are not seeing a commensurate increase in the quality of training transfer. There is evidence that simulator development that focuses on perceptual fidelity alone may prove superficial in terms of training value yield and developmental investment return. Some researchers suggest that simulator development that fixates on perceptual fidelity, at the expense of system and behaviour fidelity may in fact be undermining the students’ ability to respond to complex and escalating non-normal situations.

The traditional approach used to develop aircraft simulator system models has relied upon modifying normal model behaviour with the use of scripts. The student operating the simulator would then respond to the stimuli/cue representing abnormal behaviour effects produced by the scripts. The scripts used to modify the model’s normal behaviour are generally limited to set sequences as they can rarely cope with the spectrum of permutations and combinations which can be manifested by a malfunction in the real world environment. Furthermore, scripting is output focused and can rarely respond to student inputs, the resulting effects usually fail to provide positive and negative reinforcement required to establish resilient learning.

The current research has been aimed at developing system models that support student interaction in order to provide positive and negative learning reinforcement when dealing with abnormal behaviour sequences (Malfunction/emergency Training). The research has also developed validation metrics such as Eye Tracking technology to discern changes in ocular behaviour and objectively measure the training/learning value of these models. Current research has been successful in objectively establishing changes in student ocular behaviour and scan behaviour when exposed to stimuli representing the different behaviour models. Figure 4 illustrates one of the research test beds with a pilot using the Tobii eye tracking glasses, while Figure 5 illustrates the test results of an experiment investigating the correlation between stimuli and resulting ocular behaviour response.

Figure 4: School Research Test Beds With A Pilot Using The Tobii Eye Tracking Glasses

Figure 5: Experimental Results Investigating The Correlation Between Stimuli And Resulting Ocular Behaviour Response


» Composite Materials and Structures

SEIT Academics (ACRU Members)Prof Evgeny Morozov (ACRU Chair)A/Prof Obada KayaliDr Rik HeslehurstDr Amar KhennaneA/Prof Andrew Neely Dr Krishna ShankarDr Murat TahtaliDr Sarah ZhangMr Alan FienDr M A Ashraf

SEIT Postgraduate StudentsMr Mustafizur RahmanMr Anup ChakraborttyMs Jingfen ChenMr Chunguang WangMs Zhifang ZhangMs Xiaoshan LinMr Chang LinMs Yuan FangMs Xiaodan TengMr Karthik Ram RamakrishnanMr Md Sayem UddinMr Ahmed Mostafa ThabetMr Md Shakhaout Hossain KhanMr Md Younus AliMr Chengjun LiuMr Xiaofei WangMr Obinna Kenneth IhesiulorMr Lorin James Coutts-SmithMr He TianMr Jiting XieMs Yifei Cui Mr Kuang Yu

Other Collaborators

South China University of Technology, Guangzhou, China

Dr Jing Li

Siberian State Aerospace University, Krasnoyarsk, Russia

Prof Alexander LopatinDr Vladimir Nesterov

Australian National University, Canberra Health

A/Prof Christian LueckThomas Lillicrap

Queens University Belfast

Dr Gawn McIlwain

Research DescriptionApplications of advanced composite materials in the aerospace, oil and gas, high-end machines, antennas and marine industries are gaining more and more significance and their number is growing very intensively. Modern composite technologies are used to produce innovative products on an industrial scale. The successful development of such technologies requires an intensive research effort. In 2011, research activities undertaken by the ACRU members included development of new structural design and analysis methods, materials characterisation, understanding mechanics and physics of new processes and materials. Substantial contributions have been made in the field of a validated numerical modelling and simulation of the physical and mechanical responses of composites and structural components for a wide range of engineering applications.

Deep Water Composites (Evgeny Morozov, Krishna Shankar, Amar Khennane, Rik Heslehurst, Arif Ashraf)The project involves development of functional composite lightweight deepwater tubular structures that provide significant advantages over the existing metallic structures that are currently used by the offshore industry. The research aims to enhance understanding on the performance of composite and combined metal/composite tubular and close specific technology gaps in practical design, testing and qualification, manufacturing, installation and inspection of offshore tubular structures. The implementation of new composite design solutions will provide opportunities to reduce the installation and through life costs for the offshore oil and gas structural applications. The project is funded and coordinated by the CRC for Advanced Composite Structures Ltd. The work on the project has been undertaken in collaboration with Advanced Composite Structures Australia Pty Ltd, PETRONAS Research Sdn Bhd, University of Newcastle upon Tyne, Unique Solution Partners Pty Ltd, University of Southern Queensland, and Pacific Engineering Solutions International Pty Ltd.

Design and Modelling of Composite Offshore Risers (Krishnakumar Shankar, Evgeny Morozov)Risers for offshore drilling platforms are traditionally made out of steel. However, due to the high density of steel the depth to which steel risers can be employed is limited to about 3 km. It is envisaged that using advanced composite materials, which are well known for their light weight, strength and stiffness, risers can be employed to greater depths for deep sea extraction applications. Composite risers, however, may have their own limitations due to their susceptibility to impact. The current research involves modelling and analysing various designs of steel and fibre reinforced composite materials for the design of deep sea risers as well designs involving hybrid combinations of steel and polymeric materials.


Structural Health Monitoring of Composites using Vibration Measurement (Krishnakumar Shankar, Evgeny Morozov, Murat Tahtali)Damage in structural components affects their vibration characteristics through degradation in stiffness an/dor changes in damping characteristics. Vibration monitoring offers a powerful tool for online and continuous health monitoring of structures while they are still in service. If significant shifts in the natural frequencies of the structures are observed they indicate the possible occurrence of damage and the location and size of the damage can be assessed by solving the inverse problem. The current project aims at developing a structural health monitoring system for detecting and assessing delamination damage in composite structures.

Impact Resistance of Sandwich Panels with Nano-toughened Composite Facesheets (Krishnakumar Shankar, Philippe Viot, Murat Tahtali)This work is aimed at studying the impact resistance of sandwich panels with metallic with fibre reinforced polymer laminate face sheets whose matrix has been toughened by inclusion of elastomeric nano particles using experimental testing and numerical modelling. Improvement in impact resistance obtained by the addition of elastomeric nano particles in the matrix will be studied, with a view to optimising the percentage of the additives to achieve maximum performance.

Buckling Analysis and Design of Anisogrid Composite Lattice Conical Shells (Evgeny Morozov, Alexander Lopatin, Vladimir Nesterov)Composite lattice anisogrid shells have now become a popular choice in many aerospace applications. Their use in various structural components, such as rocket interstages, payload adapters for spacecraft launchers, fuselage components for aerial vehicles, and parts of the deployable space antennas requires the development of more advanced finite-element models and analysis techniques capable of predicting buckling behaviour of these structures under variety of loadings. A specialised finite-element model generation procedure (design modeller) is developed and applied to the buckling analysis of the composite anisogrid conical shells treated as three-dimensional frames composed of the curvilinear ribs made of unidirectional composite material. Featuring a dedicated control procedure for positioning the beam elements, the design modeller enables a close approximation of the original twisted geometry of the curvilinear ribs.

The parametric finite-element buckling analyses of the anisogrid conical shells subjected to axial compression, transverse bending, pure bending, and torsion showed the robustness and potential of the modelling approach (Fig. 1). It was demonstrated that the buckling resistance can be significantly enhanced by either increasing the stiffness of a few hoop ribs located in the close proximity to the section with the larger diameter, or by introducing the additional hoop ribs in the same part of the conical shell. The effectiveness of the design analyses is demonstrated using particular examples. It has been shown that the resultant optimised designs can produce up to 22 per cent mass savings in comparison with the non-optimised lattice shells.

Figure 1: Buckling mode of the composite lattice conical shell under axial compression.


Computational Analysis of Low Velocity Impact Response of Composite Panels (Mustafizur Rahman, Evgeny Morozov, Krishna Shankar, Murat Tahtali)The present work deals with the finite element modelling of low velocity impact response of different types of composite panels for body armour application. The response of these composites panels including bonded, unbonded and partially bonded laminates has been simulated using non-linear finite element package LS-DYNA. 2D shell elements in LS-DYNA have been used to represent both resin bonded glass fabric targets and dry woven glass fabric panels. The hemispherical shaped projectile is being modelled with 3D solid elements. The results of the numerical analysis showed that the value of contact force for the fully bonded composites panels was significantly higher than that observed for the panels consisting of dry woven glass fabric. However, the corresponding displacement was substantially lower. The similar simulation of the partially bonded composite panels has shown a reduction of both the contact force and the displacement. In addition, it has been shown that the partially bonded composite panels are capable of absorbing higher levels of energy than the rigid panels.

A Combined Elastoplastic Damage Model for Progressive Failure Analysis of Composite Materials and Structures (Jingfen Chen, Evgeny Morozov, Krishna Shankar)The paper is concerned with the development and verification of a combined elastoplastic damage model for the progressive failure analysis of composite materials and structures. The model accounts for the irreversible strains caused by plasticity effects and material properties degradation due to the damage initiation and development. The strain-driven implicit integration procedure is developed using equations of continuum damage mechanics, plasticity theory and includes the return mapping algorithm. A tangent operator consistent with the integration procedure is derived to ensure a computational efficiency of the Newton-Raphson method in the finite element analysis. The algorithm is implemented in Abaqus as a user-defined subroutine. The efficiency of the constitutive model and computational procedure is demonstrated using the analysis of the progressive failure of composite laminates containing through holes and subjected to in-plane uniaxial tensile loading. It has been shown that the predicted results agree well with the experimental data reported in the literature.

Design and Analysis of the Composite Lattice Frame of a Spacecraft Solar Array (Evgeny Morozov, Alexander Lopatin)

A novel design of the composite structural lattice frame for the spacecraft solar arrays has been developed (Fig. 2). The frame is composed of two flat lattice composite plates assembled into the three-dimensional panel using frame-like connectors (Fig. 3). Design, fabrication, modelling and modal analysis of the panel solar arrays based on the proposed technology are discussed. The lattice panels are modelled as three-dimensional frame structures composed of beam elements subjected to the tension/compression, bending and torsion using the specialised finite element model generator/design modeller. Results of the calculations of the frequencies and vibration forms for the lattice panels with various types of supports imitating the ways the panels can be attached to the spacecraft body, deployment must, and adjacent solar panels are presented and discussed. The lattice frame design for maximum fundamental frequency is performed subject to constraints imposed on the geometrical parameters of the solar panel.

Figure 2: Solar wing design. (Courtesy of ISS-Reshetnev Company).

Figure 3: Lattice frame design and placement of the connectors: (a) dense rib layout; (b) sparse rib layout.


Finite Element Modelling and Buckling Analysis of Anisogrid Composite Lattice Cylindrical Shells (Evgeny Morozov, Alexander Lopatin, Vladimir Nesterov)The buckling behaviour of anisogrid composite lattice cylindrical shells subjected to axial compression, transverse bending, pure bending, and twisting has been investigated. The lattice shells are modelled as three-dimensional frame structures composed of the curvilinear ribs capable of withstanding the tension/compression, bending in two planes and twisting. Geometric and finite element models of the lattice shells are generated using the rotation, copying, and translation of the universal typical unit cell.

The dedicated procedure (finite element model generator) is developed to control the orientation of the beam element allowing the original twisted geometry of the curvilinear ribs to be closely approximated. The effects of varying the length of the shells, the number of helical ribs and the angles of their orientation on the buckling behaviour of lattice structures are examined using parametric analyses. The influence of reinforcements around the cutout edges (Fig. 4) for the lattice shells having the holes is also investigated. The results show that these parameters strongly affect the values of critical loads and buckling mode shapes of the CFRP lattice shells subjected to various loadings. It is shown that the discrete modelling approach presented in the paper provides a sufficiently accurate buckling analysis of the lattice shells and, at the same time, can be efficiently employed in solving the relevant design and design optimisation problems.

Figure 4: Buckling mode for the cylindrical composite lattice shell with the reinforced cutouts.


Fundamental Frequency of an Orthotropic Rectangular Plate with an Internal Centre Point Support (Alexander Lopatin, Evgeny Morozov)A method of calculating the fundamental frequency of an orthotropic rectangular plate with a centrally located point support and free edges has been developed. (Figs. 5 and 6) The variational equation of motion is derived by applying Hamilton’s principle. The analytical approach determining the fundamental frequency of the plate is developed using the generalised Galerkin method and verified by comparison with the results of the finite element modal analysis. The comparisons of the computational results indicate that the fundamental frequency of the centre-supported plates can be calculated with sufficient accuracy using the analytical technique developed in this work. The approach proposed in this work can be efficiently employed when designing composite rectangular plates for a specified value of the fundamental frequency.

Performance of Outside Filament-wound Hybrid FRP-concrete Beams (Anup Chakrabortty, Amar Khennane, Obada Kayali, Evgeny Morozov)A novel configuration of a hybrid FRP-concrete beam has been developed. The beam consists of a GFRP pultruded profile, a CFRP laminate, and a concrete block all wrapped up using filament winding. Three different concrete blocks were used: high strength concrete, normal strength concrete and steel fibres reinforced high strength concrete. The major feature of the design is that it does not mimic that of reinforced concrete as reported previously. The CFRP laminate is not designed to fails first to serve as a warning of imminent failure, but rather to enhance the stiffness of the beam by compensating for the lack of stiffness of the GFRP profile. The experimental results have shown that this approach is successful. The wrapping did not only eliminate the risk of premature failure as a result of the concrete block debonding from the pultruded profile, but it was also found to enhance the stiffness and load carrying ability of the beams. The beams with a high strength concrete block showed increased stiffness and load carrying ability but failed in a catastrophic manner. On the other hand, the beams with normal strength and steel fibres reinforced high strength concrete showed improved ductility. The amount of energy dissipative behaviour was found to depend on the thickness of the concrete block. When the latter is too thin, failure akin to shear punching appears to take place.

Figure 5: Laser corner reflector.

Figure 6: First mode shape of the vibrations of the square isotropic plate.

Figure 7: Failure mode of the filament-wound hybrid FRP-concrete beam.


Integrated Plain and Slurry Infiltrated Fibre Concrete (IP-SIFCON) Composite Beams (Chang Lin, Obada Kayali, Evgeny Morozov, David Sharp)Composite beams (IP-SIFCON) were composed of two layers; a bottom SIFCON layer and an upper layer manufactured of plain cement paste. Beams made totally with SIFCON were also investigated for comparison. The effects of the SIFCON layer thickness on the flexural strength and energy absorption of composite beams were reported. The IPSIFCON beams exhibited a distinctive deflection hardening behaviour and performed comparatively with total SIFCON beams. The studies indicate that, compared with normal concrete beams, the IP-SIFCON composite beams have significantly improved flexural strength and energy absorption capacity.

Management of Aging Composite Airframes (Rik Heslehurst, Eric Wilson, Aaron Warren)The investigation of the adequacy of current Aircraft Structural Integrity (ASI) methodologies for composite airframes and proposal of changes needed to accommodate the usage of composites in aircraft structures. Developed concept for the application of accident causation models and resilience engineering to the assessment of the impact of composites to ASI. Conference paper presented at 2011 Aircraft Airworthiness and Sustainment Conference, Brisbane, June 2011, titled, ‘Evolution of Aircraft Structures and Integrity Management’.

The Effect of Saltwater Absorption/Desorption on the Residual Strength of Carbon Fibre Reinforced Composite Materials (Rik Heslehurst, Eric Wilson, Chris Kourloufas)This research is an investigation of the effect the cycle of absorption and desorption of saltwater has on the mechanical properties of Carbon Fibre Reinforced Plastics (CFRP). It has been identified from a survey of relevant literature, that the use of CFRP is ever increasing in the aerospace industry however, this topic is one that has had little research even though it is of great importance. Thus, the objective of this research is to add to the body of knowledge regarding the environmental degradation of CFRP. The focus of this research will be a literature review on the mechanisms of saltwater absorption/desorption and its effects on CFRP and/or FRP in general, and experimentation of CFRP specimens conditioned with saltwater. The experimentation will aim to determine whether absorption and desorption cycles of saltwater does leave trace elements, and whether the presence of these trace elements affect the mechanical properties of the CFRP.

Conference paper presented at 2011 Aircraft Airworthiness and Sustainment Conference, Brisbane, June 2011, titled, ‘A Review of the Effects of Fluid Absorption/Desorption on the Residual Strength of Carbon Fibre Reinforced Composite Materials.

Investigation of Innovative Aeroelastic Structure Designs Manufactured from Composite Materials to Reduce High Speed Aerofoil Drag (Rik Heslehurst, Warren Smith, Lorin Coutts-Smith)Expansion of the analytical methods for assessing bend-twist coupling of laminates to consider effects of ply-position/orientation in anisotropic laminates. Development of the understanding of laminate ply-position/orientation effects in sandwich structure. Assessment of the effectiveness of anisotropic laminates used as skins for aeroelastic aerofoils made from sandwich structure. Development of a practical application of an elastically tailored laminated structure that has been designed to make use of usually problematic aeroelasticity.

Resin Bleed Schedule Impact on Composite Specific Properties (Rik Heslehurst, Anne-Marie Lane)When composite structures are cured they often use a resin bleed schedule to control the amount of resin removed during the process. This resin removal equates to variation in the fibre volume ratio. Hence, the specific engineering properties of a composite laminate are controlled by the fibre volume ratio or bleed schedule. Five different resin bleed schedules were used to produce a series of testing coupons. Five mechanical tests were then conducted on each bleed schedule coupons. These mechanical tests were tension, compression, flexural bending, in-plane shear and short-beam shear. The results of the testing found that there exists a noticeable effect between the bleed schedule used and mechanical properties achieved. This is due to the impact that the amount of resin bleed has on the thickness and the fibre-volume ratio of the composite product. As such this research activity supports the importance of considering the resin bleed schedule used during the manufacture of an advanced composite material when attempting to achieve consistent composite engineering structural properties. The results highlighted the importance of a well defined resin bleed schedule to ensure appropriate engineering properties of the composite material.


Manufacturing Defect Tolerance in Critical Locations (Rik Heslehurst, Shayne Hohensee)The rate of introduction of lightweight composite materials into the bicycling industry has seen several front forks fail resulting in serious injury and in some cases fatalities. Research has been conducted through a sensitivity analysis in the design issues associated with bicycle carbon fibre composite front fork failures. The study determined the position of the of maximum centre of gravity effect of the bicycle and rider system which then leads to a force balance of a bicycle in motion, upright and at a constant velocity when it is subject to a step input (a curb). A theoretical analysis of the forces involved in the impact was applied to a finite element model of the front fork of the bicycle. The finite element model provided the load distribution of such impact forces which can be used as a comparison for the carbon fibre composite design and layup stacking sequence for carbon fibre composite forks. These results were then use to identify critical defect size and position near the crown of the front forks. These initial results clearly showed the sensitivity of the structural integrity of the front forks to defects.

Structural Performance of Steel/FRP Reinforced Concrete Beams at Elevated Temperature (Sarah Zhang)Fiber reinforced polymers (FRPs) such as Glass-fiber reinforced polymers (GFRP), Carbon-fiber reinforced polymers (CFRP) and Aramid-fiber reinforced polymers (AFRP) have been widely introduced to the construction of concrete structures in recent years. Due to their superior virtues, such as high tensile strength, excellent electrochemical corrosion resistance and cost-effective fabrication, they are increasingly used as a substitute of traditional steel reinforcement especially in severe environments. However, most of applications of FRP reinforcing bars are, at present, restricted to the constructions in which temperature effect is not a primary concern, which may be attributed to the fact that the mechanical properties of FRPs deteriorate with the increase of temperatures.

Hitherto, few investigations on the behavior and endurance of FRP-reinforced concrete structures at elevated temperatures have been reported. There is still no mature design guidelines available for FRP-reinforced concrete structures in aggressive environments, such as in fire condition, which is one of the inevitable threats to building structures. It is therefore essential to understand the structural behavior of FRP-reinforced concrete members at elevated temperatures before implementing them in building structures. Nonlinear finite element analyses have been employed to predict the structural behavior of concrete structures successfully. But according to the authors’ investigation, nearly all the previous researches on numerical analyses of concrete structures at elevated temperatures have been focused on the conventional steel-reinforced concrete structures, and very few numerical analyses of FRP-reinforced concrete structures under a combination of thermal and mechanical loading up to failure have been conducted.

In this research [Lin and Zhang 2011] a one-dimensional two-node layered composite beam element is developed for nonlinear finite element analysis of steel/FRP-reinforced concrete beams under under a combined mechanical and thermal loading in fire conditions. By employing the Timoshenko’s composite beam functions to construct the new element, shear-locking problem is avoided naturally and a unified formulation for analyses of both slender and deep beams is established. A nonlinear finite element analysis based on heat transfer theory is performed to determine the temperature distribution across the cross-section of the beam. Both geometric and temperature-dependent material nonlinearities are accounted for in the finite element model for accurate modelling. Numerical modelling demonstrates that the element is computationally effective, and is efficient and accurate for analyses of steel/FRP-reinforced concrete beams. The element is then employed to investigate the influences of a series of parameters such as concrete cover thickness, type of reinforcements including GFRP, CFRP and AFRP, and load levels on the structural behavior of FRP-reinforced concrete beams in fire conditions. The effects of these parameters on the structural behavior are summarized and concluded which will provide guidance for structural analyses and design.

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Figure 8: Temperature distributions across the cross-section of a beam at different fire exposure time predicted from the finite element heat transfer analyses


Nonlinear Finite Element Analyses of Steel/FRP Reinforced Concrete Beams with Debonding Effects (Sarah Zhang)Bond between concrete and reinforcing bar is one of the main traits of reinforced concrete structures, and it plays an important role in transferring the stress from reinforcing bars to the surrounding concrete. However, with the increase of loading, cracking occurs inevitably, which results in the reduction of the bond strength. And a certain amount of bond-slip may take place in the beam, which will affect the stress distribution, crack spacing, crack width as well as structural behaviour of concrete beams. Although FRP rebars show lower bond strength values than steel rebars, when there is no sufficient surface preparation, the effect of bond-slip on the structural behaviour of reinforced concrete beams shouldn’t be ignored.

In this research, a simple one dimensional composite beam model considering the bond-slip effects is developed for modelling of the structural behaviour of steel/FRP reinforced concrete beams. The model is validated by comparing the numerical results with those from the experimental studies. The modelled results using the model are also compared with those obtained from the model without considering the bond-slip effect and other numerical analyses. It is demonstrated that the model can capture the bond-slip effects accurately and effectively. Parametric effects on the structural behaviour of the beams with the bond-slip effects are also investigated.

Experimental Investigation of the Structural Behaviour of Steel/FRP Reinforced Concrete Beams (Sarah Zhang)

In this research, the structural behaviour including the debonding failure of the steel/FRP reinforced concrete beams is investigated experimentally. Four-point bending tests are carried out on the concrete beam reinforced with steel rebars, glass fiber, carbon and basalt fiber rebars. Bond-slip is tested and recorded. The effects of the different types of reinforcement are compared and analysed. The tested results are also compared with those from the developed finite element model with and without bond-slip effects.

Structural Performances of ECC Panels under High Velocity Impact (Sarah Zhang)Fibre-reinforced engineered cementitious composite (ECC) are composed of cement, water, sand, fly ash and some chemical additives with a moderate volume fraction of randomly distributed short fibres. It has been concluded as a competitive substitute for concrete in protective structures due to its potential to resist impact. ECCs are classified into two types, i.e. mono-fiber ECCs, which consists of only one type of fibers, and hybrid-fiber ECCs consisting of more than one type of fibers. A hybrid-fibre ECC, with proper volume of high and low modulus fibres, is expected to exhibit a simultaneous improvement in ultimate tensile strain and strength properties, which are both essential for protective structures.

This research develops a new hybrid-fiber ECC material with 1.75% polyvinyl alcohol fiber (PVA) and 0.58% steel fibers (SE) fibers with (PVA) and (SE) for high strength, good ductility and excellent resistance. The material properties and mechanical behaviour of the new material are investigated experimentally. These include the compressive strength, elastic modulus, modules of rupture, and tensile materials under dynamic loading rate. The high-velocity impact responses of the material is investigated experimentally subjected to the impact of a small ogive-nose projectiles fired from gas gun with initial impact velocities in the range of 300 m/s and 657 m/s. To compare the impact resistance of the new ECC mix, impact responses of a hybrid-fiber ECC with with 1.5% PVA and 0.5% SE fibers, which was recommended as the best ECC mix to resist impact by are also studied experimentally. To compare the impact resistance capability of the hybrid-fiber ECC panels with the conventional concrete panels, impact responses of plain concrete panels made of grade N45 and grade N90 normal concrete are also tested in this research.

Figure 9: Temperature-deflection relationships of concrete beams reinforced with CFRP (Beam IV-T1), GFRP (Beam IV-T2) and AFRP (Beam IV-T3)


High speed camera is used to record the whole penetration process, and the damage parameters, such as crater diameter, penetration depth, scabbing diameter, residual velocity, fragment rate, impact energy and energy absorption are determined, analysed and compared. The research findings are finally summarized and concluded finally. The experimental results from this study provide additional information in understanding of behavior of hybrid-fiber ECC structures under high velocity impact loading.

High Velocity Impact of a New Hybrid-fiber ECC (Sarah Zhang)ECC is characterised by a number of desirable mechanical properties, such as an improved modulus of rupture, fracture toughness, fatigue resistance, impact resistance, and significant strain-hardening behaviour. There is significant potential for ECC to be used in defensive and protective structures due to its capacity to resist impact. A number of experiments have been conducted to investigate the material properties of ECC mixes, but mainly on mono-fibre ECC mixes consisting only one type of fiber, such as steel fiber (SE), PVA fiber or PE fiber. Very few studies have been reported on the mechanical properties of the hybrid-fiber ECC mixes, which consist of more than one type of fibers, and no research has been reported on the dynamic material properties of the hybrid-fiber ECC mix.

A new hybrid-fiber ECC mix containing 1.25% steel fibres and 0.75% PVA fibres is proposed based on the standard ECC design in this research. The new ECC mix is expected to exhibit excellent strength, ductility and energy absorption for good capability of impact resistance. Material properties of the new hybrid-fiber ECC mix are tested experimentally with a specific focus on tensile properties under static and dynamic loading. Tests performed on the ECC mix include quasi-static uniaxial compression and tension tests, elastic modulus test, flexural test, and dynamic uniaxial tensile test. Experimental results are summarized and analysed and conclusions are drawn based on the analyses [Hermes et al. 2011 ].

There has been very little research into the high velocity impact behaviour of ECC containing both high modulus and low modulus fibres. These hybrid-ECC’s have shown promise to provide many beneficial properties over normal steel reinforced concrete including greatly increased ductility, strain hardening behaviour, greater durability and increased energy absorption. The impact resistance and energy absorption properties of the hybrid-ECC are investigated in this research.

A number of high-velocity impact test on hybrid-ECC panels using fabricated steel projectiles fired from a laboratory gas-gun and standard rifle round fired from an in-service military rifle are carried out [Bell et al. 2011]. In addition, the ballistic tests of panels with dimension of 300 mm x 170 mm x 55 mm made of conventional concrete, high strength concrete, steel-reinforced concrete, steel-fiber reinforced concrete are also carried out in this research. The impact responses of the different construction materials in terms of crater sizes and damage failure mode are analysed and compared. The results from the gun gas facilities and the real bullets are compared. The test results demonstrate significantly improved impact and shatter resistance of the new hybrid-ECC mix with reduced spalling and fragmentation, localized damage areas, improved cracking resistance with distributed microcracking and increased energy absorption capability.

FIGURES 10 – 13: The images of the damaged panels under the impact from 7.62 mm projectile fired from military SR-25 rifles.

Figure 10: Damaged hybrid-ECC panel

Figure 11: Damaged steel-fiber reinforced FRC panel


Evolution and Calibration of a Numerical Model for Modelling of Hybrid-fibre ECC Panels under High-velocity Impact (Sarah Zhang)The investigation of the dynamic responses of the ECC structures plays a significant role in the understanding of the physical mechanisms and the development of practical design guidelines for application of ECC materials in protective structures. Among the methods to study the performances of the ECC structures under dynamic loading, numerical simulation is a widely used one considering the costs related to experimental investigation and the difficulty of the analytical method. For accurate numerical prediction of the dynamic behaviour of the ECC structures, an appropriate material model which can represent the dynamic behaviour of ECC materials and equation of state (EOS) are essential.

In this research several widely used material models for plain concrete under dynamic loading, especially the Concrete Damage model and the Elastic-Plastic Hydrodynamic model are evaluated so as to determine an appropriate material model for engineered cementitious composite (ECC) materials under dynamic loading. The effects of size effect, strain rate effect and the specific equation of state on the dynamic material behaviour are investigated using numerical modelling method. A material model which is appropriate to simulate the dynamic behaviour of ECC materials is established based on the Concrete Damage model. The proposed material model is validated via numerical simulation of the impact process of a hybrid-fibre ECC slab struck by a high-velocity projectile. Advantages and limitations of other material models for dynamic behaviours of ECC materials are also compared and commented [Li and Zhang, 2011].

Nonlinear Numerical Modelling of FRP Strengthened Concrete Slabs (Sarah Zhang)Due to the superior material properties of the fibre reinforced polymers (FRPs), such as high ratio of stiffness to weight and strength to weight, resistance to fatigue and corrosion, they have been used to strengthen and rehabilitate deteriorated concrete structures and infrastructures, such as bridges. Moving vehicles generally produce significant responses than equivalent static loads do. Vehicle-induced dynamic response of bridges is one of the primary problems for bridge engineers.

In this research, a finite element model is developed to investigate the structural behaviours of a FRP-strengthened bridge deck system under moving vehicle loadings. Finite element analysis of a full-span continuous FRP-strengthened box girder steel reinforced concrete bridge model under moving vehicles is conducted. In order to validate the analysis procedure, the static and modal analyses of an existing concrete bridge are firstly conducted and results are compared to those obtained from the literature. Once the procedure is validated, the model is used for analysis of a FRP-strengthened concrete bridge. Structural and dynamic behaviour including the deflection of the mid-span and other monitoring points and natural frequencies of vibration are studied. The parameters affecting the bridge dynamic responses including the speed of the vehicle and the effects of different types of FRPS including CFRP, GFRP and Basalt Fibre on the structural behaviour are studied [Teng and Zhang, 2011].

Figure 12: Damaged steel bar-reinforced concrete panel

Figure 13: Damaged high strength concrete panel (compressive strength of 90 MPa)


Biomechanics and heat transfer in the Brain (Neely, Tahtali, Lueck, McIlwaine, Lillicrap)Work on two medical-related projects has continued to apply engineering tools to clinical problems. The first concerns ongoing research to model the compression of the optic chiasm by a growing pituitary tumour and its relation to the visual defect known as bitemporal hemianopsia in which the outer half of the visual field, which is carried by the nasal optical nerve fibres, is lost. A new PhD student, Xiaofei Wang, was recruited to the project and spent 2011 performing initial FEM simulations of the resulting distortion of the optic chiasm, which is the crossing point for the optic nerve bundles passing backwards from the eyes to the brain. Simulations of individual nerve fibre models were also performed to account for the different crossing geometries in the nerve fibre bundles. These initial simulations demonstrated that the central region of the chiasm always bears higher stresses than peripheral regions. In the nerve fibre scale, the stresses in the nasal nerve fibres, which cross, are dramatically higher than in the temporal nerve fibres, which do not.

The second project has modelled the transfer of heat in the brain and its bearing on body cooling strategies for post-stroke intervention to minimize cell death in the brain. The work being performed at UNSW Canberra has used FEM to create simplified brain geometries that incorporate stroke damage and model the transfer of heat in the structure that results from various cooling strategies. This involves incorporating an analytical model for the balance of heat production and heat removal by the blood supply to the brain. Initial simulations have established the technique and the work is ongoing.

Figure 14: The displacement-time responses of the bridge with CFRP strengtheningand without strengthening under vehicles moving at speed of 30m/st

Figure 15: Displacement-time responses of the bridge with CFRP and GFRP strengthening under vehicles moving at speed of 30m/s


» Computational Intelligence

SEIT AcademicsProf. Hussein AbbassDr Sameer AlamDr Michael BarlowDr Daryl EssamDr Chris LokanDr Kathryn Elizabeth MerrickA/Prof. Ruhul Sarker Dr Kamran Shafi

SEIT Research StaffDr Vinh BuiDr Jing LiuMr. Jiangjun TangDr Weicai Zhong

SEIT Postgraduate StudentsMs. Heba Zaki Mohamed El-FikiMr. Amr Ahmed Sabry Abdel Rahman GhoneimMr. Peter HoekMs Erandi Lakshika Hene KankanamgeMr. George LeuMs. Shen RenMs. Bing WangMs. Shir Li WangMs. Kun Wang Mr. Leon YoungMr. Bin Zhang

Software Developers Mr. Qi Fan

External Collaborators

Defence Science and Technology Organisation, AustraliaDr Axel Bender

National University of Singapore, SingaporeProf. Tan Kay Chen

Defence Science and Technology Organisation, AustraliaProf. Neville J Curtis

Defence Science and Technology Organisation, AustraliaDr Svetoslav Gaidow

Monash University, AustraliaProf. David Green

UC, AustraliaAssistant Prof. Eleni Petraki

Kyushu University, JapanProf. Jun Tanimoto

Funding Agencies and Sources

Australian Research Council

Defence Science and Technology Organisation

Research DescriptionComputation underlies the science of using calculations to understand systems or solve problems in a systemic manner. Intelligence is the high mental capacity of a human being to utilize their cognitive skills in a systematic and rational way to be conscious of, understand, learn, predict and influence the surrounding environment, using justifiable actions.

Computational Intelligence is the science of using computations to represent, model and mimic intelligence. Examples of Computational Intelligence include computational problem solving methods and algorithms inspired with concepts from Nature (e.g. Evolutionary Computation, Ant Colony Optimization, Marriage in Honey Bees Optimization, Estimation Distribution Algorithms, artificial immune systems), computations through architectures that mimic the architectures of the brain (e.g. neural networks, connectionism, cognitive agents), and computations through linguistic forms (e.g. fuzzy systems, computational linguistics).

CI members are specialized in a wide variety of computational frameworks, methodologies, methods, algorithms and techniques for solving problems and understanding systems. Many projects in CI are industry driven, attempting to popularize computations in organisations and systems.

The Causes for No Causation: A Computational PerspectiveCausality is grounded in every scientific field. Computational modelling is no exception, except that it is our focus in this article. But what if we have made a mistake? Is causality a constraint on our understanding of complex systems? Is it an obstacle in our ability to build theories to control change in complex systems? Or do we merely need to refine the concept as we evolve from one level of complexity to another?

We [Abbass and Petraki] started the journey of this project by glancing over a few key pieces of work from Philosophy and Metaphysics. We then centred the research on the pivotal elements of this project, causality of change in complex systems of systems, and demonstrated that a counterfactual analysis of causality breaks down. We attempted to understand “change” and separated physical and perceptual elements. Three applications were presented as examples of the type of complexity we face in computational modelling of complex systems of systems. These three applications – covering story generation in linguistics, network centric operations in defence and interdependency security problems - demonstrate how causal dependencies can be modelled, identified and extracted from a computational environment that mimics real-world complex systems of systems. We then proposed a model – we call the E4 model - to control change in complex systems.


Evolving high fidelity, low complexity rule-based Multi Agent Simulations of standing group conversations utilising a framework bootstrapped from human aesthetic judgements This project is part of ongoing work to determine the relationship between rule complexity and fidelity of rule-based Multi Agents Systems. The objective of the framework is to derive high fidelity simulations with minimal computational complexity. The framework is presented in the domain of social simulations of standing conversation group dynamics. Four conceptual rules – inspired by the seminal boid-rules introduced to synthesize the dynamics of flock behaviours - form the building-blocks of the framework. These rules contain parameters which influence the rules while the combination mechanism combines the rules to determine the agent behaviour. Considering the number of permutations, it is a highly resource intensive to derive optimal agent configurations by manual parameter tuning. Hence the framework employs a Genetic Algorithm to search rules and the parameter space more efficiently than a human would be capable of. The Genetic Algorithm utilises a fitness function developed based on a machine learning system trained by bootstrapping human judgment on the visual fidelity of a relatively small set of training examples (agent configurations). The framework can be described using the following 5-step process.

1. Derive sets of rules to determine the agent behaviour in the Multi Agent System

2. Present sets of different agent configurations (scenarios/training examples) for human evaluation

3. Train a scorer – a machine learning algorithm – to determine the fitness (visual fidelity) of unseen agent configurations using human scores and extracted features of the scenarios

4. Use a Genetic Algorithm to evolve agent configurations utilising the automated scorer in order to derive the optimal agent configurations

5. Present evolved agent configurations back to the human validation

Computational Red Teaming: Past, Present and FutureThe combination of Computational Intelligence (CI) techniques with Multi-Agent Systems (MAS) offers a great deal of opportunities for practitioners and Artificial Intelligence (AI) researchers alike.

CI techniques provide the means to search massive spaces quickly; find possible, better or optimum solutions in these spaces; construct algorithms, functions and strategies to control an autonomous entity; find patterns and relationships within data, information, knowledge or experience; assess risk and identify strategies for risk treatment; and connect the dots to synthesize an overall situational awareness picture that decision makers can utilize.

MAS provide the structured, modular, distributed and efficient software environment to simulate systems; the architecture to represent systems and entities naturally; the environment to allow entities to observe, communicate with, negotiate with, orient with respect to, and act upon other entities; the modular representation that allows entities to store and manipulate observations, forming beliefs, desires, goals, plans, and intentions; and the framework to model behavior.

By bringing CI and MAS together, we [Abbass, Bender, Gaidow and Whitbread] have a powerful computational environment that has the theoretical potential to do many things that one can expect when attempting to structure, understand, and solve a problem. Computational Red Teaming (CRT) is the state-of-the-art architecture representing the integration of CI techniques and MAS for understanding competition. This integration of MAS and CI benefits practitioners in almost all major application domains such as defense, business and engineering. This project maps out the evolution of CRT by categorizing the different levels of integrating CI and MAS, and highlighting open research questions pertaining to CRT.


Behavioural Analysis in Computational Red TeamingRed teaming is an approach to study a task by anticipating adversary with adversary refers to an entity which affects the objectives of the task. A blue entity refers to the entity which would like to achieve the task while a red entity refers to the circumstances and/or entities which may have an adversary impact on the task. In other words, both the blue and red entities have conflicting interests. Originally, red teaming is an approach widely used in military operations to role-play the enemy; test and evaluate its courses of action or judgement; assess the vulnerabilities of the blue team; and learn to understand the dynamics existed between the red and blue entities. In a computational red teaming environment, red is not necessarily an enemy but any entity with objectives that are in conflict with blue’s objectives. The red teaming concept can be mapped in domains which share similar characteristics such as adversarial learning, risk assessment, and behavioural decision making and the concept can be expanded further with the use of computational red teaming.

A key question in Computational Red Teaming is: can an autonomous machine red team in human-like manners? This is the underlying question of this project. If we [Wang, Shafi, Lokan and Abbass] are able to establish the feasibility of using a computational environment to play the role of a red entity, we can have red teaming in silico. We would like to understand the differences of behaviour between an autonomous machine and human, and thus, shed some lights on the rationality and optimality of strategy selection. Through understanding the differences, the blue team which can be either a machine or human is able to manage their tasks effectively and this leads to better decision making.

A Computational Red Teaming based Interactive Learning Environment for Cyber Intelligence It is a fact that there are many security problems and various threats existing in the cyber environment. However, we are still learning how to deal with this new space. For information assurance, we need to understand how Cyber Intelligence differs and how to design proper effective measures of performance, measures of effect and measures of utility. As such, there is an increasing need to provide effective education and training tools for organizations and individuals. This is the objective of our research.

We [Zhang, Shafi and Abbass] integrate Simulation, Optimization and Data mining in this project to provide an Interactive Learning Environment for Cyber Intelligence. Machine learning and optimization techniques are used to derive the learning engine.

Autonomous design of creative data mining hypotheses in computational red teamingThe volume of data available nowadays exceeds the analysis capacity of experts and researchers. Data carries significant information and knowledge, but they are usually represented in terms of hidden relationship, patterns or trends. Large database are searched for such relationships, trends or patterns. These patterns are not known to exist and are not visible prior to the start of the search process. Although automated searching/knowledge discovery techniques can be used to analyse and search for such hidden knowledge, they assume human experts guiding the search process. We [Wang, Merrick and Abbass] propose methods to autonomously mine data in a Computational Red Teaming Environment.

Cognitive-Aware Adaptive GamesIn order to enhance the user game play experience, to improve the computational methods for detecting and measuring human emotions in real-time, and to develop Computational Intelligence techniques and adaptation models suitable for electronic games, we (Ren, Barlow & Abbass) design adaptive mechanisms for games by using physiological and cognitive monitoring data to create what we coin as “Cognitive-Aware Adaptive Games” (CAAG). In this project, we first design a CAAG framework. Under this framework, monitored physiological and cognitive data from the player are analyzed to obtain emotional indicators. An emotion model which maps emotional states and indicators to high-order states is developed. Adaptation is then achieved by changing the game using the full information derived from real-time monitoring of the players. CAAG could greatly enhance the game-playing experience of the player. The findings not only have entertainment value, but can also be applied to educational and training areas.

Evolutionary Story Generation MethodsIn this project, we [Wang, Bender, Bui & Abbass] propose a computational framework for automated story-based scenario generation. Under this framework, a hierarchical grammar approach is applied to model the complexity of a story at different levels of granularity —the scene-level and the event-level. We use a parameterized version of tree adjoining grammar (TAG). The potential of TAG to represent and generate complex stories has been shown in our previous work. The grammar is then evolved using evolutionary computation techniques to generate novel story plots, i.e. story-based scenarios. To evaluate these newly generated scenarios, a human in the loop model is used. Moreover, to meet the challenge of generating domain-specific stories, we propose a semi-automatic story structure finding approach and natural language processing techniques to automatically parse stories in a domain of interest into a network of interrelated events and entities, then use network analysis tool to find story patterns and features.


A Computational Intelligence Approach to Competency and Skill Assessment of Go Players Complex situations are very much context dependent, thus agents – whether human or computerized – need to attain an awareness based on that present situation. An essential part of that awareness is the accurate and effective perception and understanding of the set of knowledge, skills, and characteristics that are needed to allow an agent to perform a specific task with high performance, or what we would like to name, Competency Awareness. In this study, we propose a framework whereby a computational environment is used to study and assess the competency of a decision maker. We [Ghoneim, Essam and Abbass] use the game of GO to demonstrate this functionality in an environment in which hundreds of human-played GO games are analysed. In order to validate the proposed framework, a series of experiments on a wide range of problems has been conducted. These experiments automatically (1) measure and monitor the competency of Human Go players (See the Example Figure), (2) reveal and monitor the dynamics of Neuro-Evolution, and (3) integrate strategic domain knowledge into evolutionary algorithms. The experimental results showed that: (1) the proposed framework was effective in measuring and monitoring the strategic competencies of human Go players and evolved Go neuro-players, and (2) was effective in guiding the development of improved Go players when compared to traditional approaches that lacked the integration of strategic competency measurement.

A Computational Linguistic Approach for the Identification of Translator Stylometry in Arabic-English TextDespite the research proliferation on the wider research field of authorship attribution using computational linguistics techniques, the translator stylometry problem is more challenging and there is no sufficient literature on the topic. Some authors even claimed that this problem does not have a solution; a claim that we [El-Fiki, Petraki & Abbass] challenge in this project. We present an innovative set of translator stylometric features that can be used as signatures to detect and identify translators. The features are based on the concept of network motifs: small graph local substructures which have been used successfully in characterizing global network dynamics. The results demonstrate the efficiency of the approach.

Local-Global Interaction and the Emergence of Scale-Free Networks with Community Structures Understanding complex networks in the real-world is a non-trivial task. Researchers resort to computer-generated networks that resemble characteristics of networks encountered in the real-world as a mean to generate many networks with different sizes, while maintaining the real-world characteristics of interest. The generation of networks that resemble characteristics in the real-world turns out in itself to be a complex search problem. We [Liu, Zhong, Green & Abbass] present a new re-wiring algorithm for the generation of networks with unique characteristics that combine the scale-free effect and community structures encountered in the real-world. The re-wiring algorithm is inspired by social interactions in the real-world; whereby people tend to connect locally while occasionally they connect globally. This local-global coupling turned out to be a powerful characteristics that is required for our proposed re-wiring algorithm to generate networks with community structures, power law distributions both in degree and community size, positive assortative mixing by degree, and rich-club phenomenon.

A Competency-Level Monitoring Curve for a Human Go Player.


» Concrete Technology and Materials

SEIT AcademicsA/Prof Obada KayaliProf Evgeny MorozovDr Amar KhennaneDr Tapabrata Ray

SEIT Postgraduate StudentsChang LinYuan FangM. Shakhaout Hussein KhanM. Talha Junaid

SEIT Undergraduate studentsJuliana KarantonisMichael LynchThomas BleeckDamian Selby

Other Collaborators

Roads ACT

Dr M. Sharfuddin Ahmed

CEO-VECOR Building Systems Ltd

Mr. Alex Koszo

University of Kuwait –Kuwait

Prof M. Naseer Haque

University of Wolverhampton-UK

A/Prof. Jamal M. Khatib

Geomaterials laboratory, Civil Engineering Department, University of Blida, Algeria

Dr S. Kenai

Research DescriptionThe advances in the technology of concrete have gained momentum in the past decade. New materials, design methods, ideas, innovations and standards have been introduced. Meanwhile, the issue of sustainability of building materials in general and of the concrete industry in particular has come under careful scrutiny. This is because the production of concrete is a main source of green house emissions. To put this into perspective, it has been found that for every tonne of cement produced, there is a tonne of carbon dioxide emitted in the atmosphere. Thus the technology of concrete has taken a special direction aimed towards innovations to produce concrete that may be sustainable .

The research activities in concrete and building materials which are taking place at the School of Engineering and Information Technology have been steered towards the theme of sustainability. This has included the innovation in materials as well as research that aims to produce concrete of desirable and predictable durability. These activities are briefly described in the following paragraphs.

Performance of High Volume Fly Ash ConcreteMajor industries in Australia and around the world have been producing far too large quantities of waste. Coal power generation, iron and steel, aluminium and silicon industries all produce various ‘waste materials ‘. Although such materials are considered waste from the particular industry viewpoint, they can be of enormous value for concrete and building industries. The facts however are: (a) concrete manufacturing is one of the major causes of green house gas emissions, (b) the industrial waste can be an environmental hazard, (c) some of the waste materials actually possess properties that are very desirable to have in concrete, (d) some of these materials can substitute cement, which is the main contributor to CO2 emission in the concrete and building activities, and (d) utilising such materials is beneficial to the economy of the producing industry, the concrete industry and the society. Thus it makes sense to direct research to assess the properties and effects of replacing cement by a large amount of waste materials such as fly ash, blast furnace slag, metakaolin and silica fume. In the years 2010/2011 findings from our concrete research have been published and presented in international journals and conferences. The positive contributions of the use of ground granulated blast furnace slag as a large volume replacement of cement has been systematically studies and reported. A rigorous comparative study of the effects of fly ash inclusion in large quantities, have been reported in a couple of important publications and is expected to importantly contribute to the knowledge in this area.

Measurement of corrosion current in the reinforcement

Compressive strength as a function of fly ash replacement


Engineering Cementitious Materials and The Use of FibresDevelopments in the science of fibre reinforced concrete are expected to have far reaching effects on the durability of structural concrete. Already high performance fibre reinforced cementitious composites have been successfully applied to the retrofitting of damaged concrete beams. External strengthening of various elements of civil engineering construction has become very popular with the use of fibre reinforced polymer composites. Fibre reinforced plastics have been very much researched and successfully employed in retrofitting structures that were not initially designed to withstand seismic loads. Moreover, the recent advances in the manufacturing of fibre reinforced cementitious materials have made it possible to effectively resist seismic loading resulting in saving of lives as well as structures. The significant reduction in crack width and permeability that the engineered fibre reinforced concrete can achieve, has made it possible to protect coastal structures against reinforcement corrosion and thus significantly prolong the life expectancy of structures. Research in this area has taken important strides that established engineered fibre reinforced cementitious materials as a most promising area of research in the School.

Stress-Strain diagrams for Engineered Cementitious Materials

Load-deflection curves of fibre reinforced concrete beams made with Engineered Cementitious Composite materials

Scanning Electron Microscopy of Engineered cementitious materials


Geopolymer ResearchGeopolymer is now promising to be a major building material. Its importance is that it can be made from industrial wastes and by-products. The use of fly ash and blast furnace slag in manufacturing this type of concrete is anefficient way to get rid of the waste

material as well as to create an excellent performing concrete and reduce the dependence on cement. The figures below show some results obtained through research into the nature and behaviour of geopolymer concrete.

Back-scatter image of fly ash

Scanning Electron Microscopy in Geopolymer Rresearch

Bond of reinforcement in ordinary portland cement concrete

Bond of reinforcement to geopolymer concrete

XRD of geopolymers at various stages (M: Mullite, Q:Quartz, G: Gypsum, P:Portlandite, A: Albite, L: Labradorite)


Research into printable concreteThis research is focused on exploring admixture interactions in order to develop an acceptable concrete that can be used in a potential automated construction process. This automated construction process can be described as concrete printing. Printing concrete construction involves concrete being pump through a system to be extruded into its desired shape without form work.

This research explores the issues involved with developing a concrete that is structurally viable and can meet the requirement to make this construction process possible. In order to make this possible, rapid setting must be achieved. Therefore hydration of cement is explored along with the use of accelerators. In addition, the uses of super-plasticisers containing air entrainment properties are explored to see if they are beneficial in the creation of a printable concrete.

Optimization of mix design using optimized particle size distribution algorithmOptimum mix design depends to a large extent on the density values and grain size distribution of the ingredients.

UNSW Canberra possesses instruments that allow the study of grain size as well as the specific gravity values of concrete constituents. This project develops an algorithm that optimizes the proportions of concrete ingredients based on particle size distributions and mix design grading requirements.

Particle Size Distribution of Cement, Ground Granulated Blast Furnace Slag, Silica Fume and Fly Ash using equipment at UNSW-Canberra.

Effect of accelerating and superplasticiser admixtures on concrete strength


» Control Theory and Control Applications

SEIT AcademicsProf Ian R. Petersen A/Prof Hemanshu R. Pota A/Prof Valeri Ougrinovski

SEIT Postgraduate StudentsMs Ning Chuang Mr Hua Ouyang Mr Sayed Sayed-Hassen Mr Hendra Harno Ms Aline Maalouf Mr Obaid Rehman Mr Md Apel Mahmud Mr Ahmed Fathi Abdou Mr Rabiul Islam Mr A. B. M. Nasiruzzaman Mr Adnan Anwar Mr Md. Sawkat Ali Mr Naruttam Kumar Roy Mr Abdul Barik Mr Md. Shihanur Rahman Ms Tahsin Fahima Orchi Mr Habibullah Habib Mr Sajal Kumar Das Mr Md. Sohel Rana Mr Tushar Kranti Roy Mr Shanon Vuglar Mr Mohamed Mabrok Mr Cheng Yi Ms Medria Hardhienata

SEIT Research StaffDr Abhijit Kallapur Dr Daoyi Dong Dr Dabo Xu Dr Igor Vladimirov Dr Hamid Teimoori Sangani Dr Mahendra SamalDr Luis Duffaut Espinosa

Other Collaborators

SEIT, UNSW Canberra

Prof Elanor Huntington A/Prof Charles Harb Mr Toby Boyson Dr Kathryn Merrick Prof Jiankun Hu Dr Matt Garratt Dr Sreenatha Anavatti

School of Engineering Systems, QUT

Dr Jason Ford

University of Illinois at Urbana-Champaign

Prof Cedric Langbort Mr Takashi Tanaka

Australian National University

Prof Matthew R. James Dr Hendra Nurdin Mr Zibo Miao

University of Manchester

Dr Alexander Lanzon Ms Zhuoyue Song Mr Sonke Engelken Dr Sourav Patra

University of San Paulo , Sao Carlos

Dr R. A. Ramos

Keio University, Japan

Dr Naoki Yamamoto

University of Newcastle

Prof. S. O. R. Mohiemani

University of Waterloo

Dr Baris Fidan

Albert-Einstein-Institut Hannover

Juniorprof. Dr Michele Heurs

IIT Madras

Dr A.J. Shaiju Dr B. Bhikkaji

Research DescriptionFeedback control systems are widely used in manufacturing, mining, automobile and military hardware applications. In response to demands for increased efficiency and reliability, these control systems are being required to deliver more accurate and better overall performance in the face of difficult and changing operating conditions. In order to design control systems to meet the demands of improved performance and robustness when controlling complicated processes, control engineers require new design tools and better underlying theory. The Control Research Group conducts fundamental research into theory and applications of automatic control systems. Particular interests of the members of the group include theory of optimal and robust control systems, quantum control, stochastic control systems, and applications to active noise control, signal processing, navigation and guidance. The Control group receives financial support from the Australian Research Council and the Defence Science and Technology Organisation.


Constructive control of interconnected systemsThe aim of this project supported by the ARC Discovery project awarded to A/Prof Ougrinovski in 2008 is to develop a constructive feedback control theory of complex interconnected systems that is focused on new distributed and decentralized control methodologies, by combining the method of vector Lyapunov functions with advanced approaches of robust, stochastic and nonlinear control.

In 2010 we continued research into the development of observer-based algorithms for distributed estimation of uncertain systems which began in 2009. The objective is to develop constructive algorithms for the synthesis of networks of interconnected robust estimators. Our approach is to treat this problem as a distributed control problem where one seeks to design appropriate interconnection control protocols for exchanging information between the nodes. This year we applied the approach of vector dissipativity and vector Lyapunov functions to allow for the design of networks of robust observers connected over randomly failing channels. The main result obtained in 2011 is a sufficient condition which guarantees a suboptimal H∞ level of disagreement of estimates in a network of filters which use only locally available information about the network connectivity. It involves solving a optimization problem subject to LMI and rank constraints.

The research into connective stability of stochasitc nonlinear systems has been finalized. A known result in the stability theory of stochastic systems with nonlinear Lipschitz-bounded noise intensity states that the robust stability radius of such a stochastic system is equal to the inverse of the H2 norm of its ‘noise-to-output’ transfer function. This research extends this result to the case where one is interested in the diagonal stability of the system under consideration. This problem arises naturally when studying large-scale interconnected systems subject to random perturbations, as one is often interested in using diagonal or block-diagonal Lyapunov functions for such plants. The main result of this research is the characterization of the diagonal stochastic stability radius, which is similar to the mentioned result for non-diagonal stability.

We also considered the problem of measurement feedback decentralized stabilization of large-scale interconnected nonlinear systems. Motivated by the recent developments on control vector Lyapunov functions, the notion of an output control vector Lyapunov function is defined which serves as a starting point for the investigation of a decentralized version of feedback stabilization problem for such systems. This paper focuses on the measurement feedback decentralized stabilization problem. The main contributions of this research are solutions to the static version of the problem. An example is given to illustrate the proposed design methods.

Robust Filtering of Uncertain Hidden Markov Models with Conditional Relative Entropy ConstraintsWe consider a robust filtering problem for uncertain discrete-time, homogeneous, first-order, finite-state hidden Markov models (HMMs). The class of uncertain HMMs considered is described by a conditional relative entropy constraint on measures perturbed from a nominal regular conditional probability distribution given the previous posterior state distribution and the latest measurement. Under this class of perturbations (which is assumed to contain a corresponding regular conditional probability measure corresponding to the true system), a robust infinite horizon filter is first formulated as a constrained optimization problem before being transformed via variational results into an unconstrained optimization problem that can be elegantly solved using a risk-sensitive information-state based filtering problem.

Control Theory and Its Application to Pendulum-like SystemsThis project addresses the stability analysis problem and the stabilizing controller synthesis problem for pendulum-like systems with multiple nonlinearities. As existing method for analyzing the Lagrange stability of pendulum-like systems with single nonlinearity is generalized to pendulum-like systems with multiple nonlinearities. Also, a non-degeneracy condition of the existing Lagrange stability criterion is removed and a strict frequency-domain inequality is used instead. To study the synthesis problem, this project develops an Extended Strict Bounded Real Lemma for systems which are not stable but stabilizable. A sufficient condition for state feedback control design is proposed in terms of a sign indefinite solution to an algebraic Riccati equation.

Autonomous deployment and recovery of rotary wing UAVs from moving platformsThis project is made up of several diverse component --- sensor technology, signal processing, real-time control, system identification, and nonlinear control.

For this research we have a couple of experimental helicopters (UAV) - RMAX and Eagle. The helicopters are instrumented with GPS sensors, inertial measurement units, laser rangefinder systems, and a research platform for ultrasonic sensors.

In 2011 two controllers were designed to attenuate gust disturbances during hover (a) Model predictive control, and (b) backstepping control including sensor delays. The experimental testing of these controllers is planned for 2012.


Renewable Energy Integration in Power GridsModern power system grids are interconnection of synchronous generators and electrical loads, separated over huge distances of the order of few thousand kilometres. The first line of power system controllers are (a) input mechanical power controllers, which match it to the electrical output power, and (b) voltage controllers, which maintain a fixed voltage. Owing to the ever increasing load and reluctance to build new power stations, more and more power is being pushed over the tie-lines in grids. These high tie-line power flows make the interconnected system dynamics tightly coupled and often makes the system critically stable.

In order to operate critically stable systems a damping signal, using the generator speed as input, is generated by what is known as power system stabilisers (PSS). Classical power system stabilisers are designed for nominal operating point of the system. In this work we partition the entire power system operating range and then design a PSS for a nominal point in each partition.

In 2011 analysis and control design was done to integrate renewable generation in distribution systems. The approaches researched were (a) including FACTS devices for voltage profiel control, (b) complex network based analysis to identify critical system links, (c) multi-agent based control for fault recovery, and (d) the use of plug-in hybrid vehicles to improve the power quality in distribution systems.

Robust Feedback Control in Quantum TechnologyDevelopments in quantum technology are presenting new challenges to control theory. There is a need for robust feedback control design methods for quantum systems that are capable of achieving desired performance while compensating for the detrimental effects of uncertainty, decoherence and noise, and taking into account the fact that measurements affect the dynamics of quantum systems.

Standard control methods do not take into account the special features of quantum systems; these features, however, are critical to the operation of these systems and provide opportunities beyond those available in classical systems. This project addresses these challenges by developing a new theory of robust feedback control for quantum systems. Research in this project is currently directed towards developing quantum versions of standard control theory techniques such as LQG control and H-infinity control and also applying evolutionary optimization techniques to these problems. This research is exploring the use of controllers which are themselves quantum systems along with mixed classical and quantum controllers. A practical side of this research is concerned with the frequency locking problem for optical cavities, applying modern control techniques such as LQG control. Three PhD students are working in this area and their research has involved both theoretical development of robust quantum control theory as well as the experimental implementation of an LQG controller in locking an optical cavity.

Negative Imaginary Systems and the Control of Flexible structures and Nano-positioningMany industrial and scientific devices include components that can be classified as flexible structures, Flexible structures are highly resonant systems, and therefore susceptible to high amplitude oscillations even in the presence of weak disturbances. These oscillations can result in significant loss of precision and possible breakdown if the amplitude of oscillations crosses the elastic limit. Thus, there is a clear need to damp or control the oscillations that arise in flexible structures.

A large number of control design techniques have been proposed for this purpose. In particular, there has been significant and growing interest in control design for flexible structures with collocated sensors and actuators. This project is concerned the theory of Negative Imaginary systems which leads to a number of important methods for controlling flexible structures. Applications of this research include the use of piezo-electric actuators in nano-positioning in areas such as atomic force microscopes and in optical cavities.

Control of Hypersonic VehiclesThis research is concerned with the application of methods of robust and nonlinear control theory to the problem of designing a flight control systems for a hypersonic vehicle. Using existing models available in the literature, the method of feedback linearization can be applied to design a flight control system. However, the available models are know to be highly inaccurate due to a lack of experimental data. Hence, in this research, the feedback linearization method is combined with uncertainty modelling and minimax optimal control methods to design nonlinear robust controllers for hypersonic vehicles. One PhD student is currently working on this project.

The UNSW Canberra power system testbed.


» Cyber SecuritySEIT AcademicsProf. Jiankun Hu Dr Lawrie BrownDr Robert StockerDr Frank JiangDr Kathryn MerrickProf. Ian Petersen

SEIT Postgraduate StudentsMr Wencheng YangMr Kai XiMs Wanrong Wu

Other Collaborators

School of Computer Science, University of Western Australia

Prof. Mohammed Bennamoun

RMIT University

Prof. Z. Tari, Dr F. Han, Dr Ibrahim Khalil, Prof. Xinghuo Yu

Beihang University, China

Dr Jihao Yin

Research DescriptionCyber security is a major concern in our information age and will become more threatening due to the ubiquitous network connections and more advanced and automated attacks tools available. Cyber attacks can intrude privacy, bring down a whole plant, communication centre, and commanding systems. Intrusion Prevention Systems (IPSs), e.g., firewalls, intend to prevent these attacks but cannot effectively deter new attacks or variations of virus what are occurring daily. How about insiders’ attacks? Such attacks do not go though network firewalls at all. Cyber security is an exciting, and challenging area/topic for both academic research and industrial applications. It will be an on-going effort in the foreseeable future.

Security strength is always upon the weakest link of the systems. Therefore cyber security is a system concept and covers a very broad spectrum including cryptography, access control, authentication, network security, intrusion detection etc. The Cyber Security group at UNSW Canberra conducts both theoretical and applied research in the aforementioned topics with emphasis on biometrics security, sensor network key management, and intrusion detection.

The Cyber Security group has received financial support from the Australian Research Council, and the University of New South Wales.

Biometric SecurityA fundamental flaw in existing embedded e-security technologies is their cryptography-plus-PIN-number infrastructure. This has generated security concerns that have proved a major obstacle to the growth of e-commerce, presently a relatively poor 2% of market share. We aim to design a new infrastructure that can solve this security problem by incorporating cryptography and biometric authentication into a computing resource limited embedded e-security system. The outcomes of this project will be a set of new cryptosystems, new biometrics processing schemes and new onboard resource allocation schemes that will form the basis for the next generation of embedded systems.

Fingerprint Related Project:Fingerprint authentication is the emerging technology for security. A fingerprint is unique and can never be forgotten. It has found many applications in banking, mobile device access control, law enforcement, customs border control etc. It is predicted fingerprint security feature will be placed everywhere. Several interesting projects are given below.

– Project 1: fingerprint registration. Most of fingerprint applications rely on registration, a process that align different imprints. This is non-trivial as each fingerprint captured tends to be different. The project tries to explore more reliable algorithms.

– Project 2: Fingerprint indexing. The size of fingerprint database is exploding and easily at the scale of 100 millions. Given an unknown fingerprint, how could you find a match reliably and fast for the very large scale databases.

– Project 3: fingerprint smart card template protection. We can use fingerprint for strong authentication. However, fingerprint biometrics stored in the smart card template need to be protected by themselves. This project tries to explore effective schemes for that


Face Related ProjectSimilar to fingerprint, face is a popular biometric authentication feature which has been applied in many places. Australia Parliament has recently (2007) passed a bill to introduce face recognition based smart cards for health and social services. However, it is still an issue on the face biometric template protection and also the false recognition rate is still very high for very large scale databases. This project tries to explore effective solutions.

Following achievements have been made:

1. One awarded ARC Linkage grant on partial fingerprint identification including 3D fingerprint identification.

2. Two ERA-A* ranking and one ERA-A ranking journal publications including the prestigious IEEE Transactions on Pattern Analysis and Machine Intelligence.

Network SecurityNetwork security is becoming a major issue in our daily life. Firewall technology seems to be insufficient as we are having more and security break-in reports on worm, various attacks. In theory, it is impossible to prevent such attacks. Therefore, it is very important to have a second defense which is intrusion detection. Several interesting projects are given below.

Project 1: Anomaly intrusion detection. Normally firewall technology can detect attacks with known features. However new ways of attack are happening all the time. There is a need to detect attacks with unknown features. Anomaly detection is a promising technology that can detect unknown attacks. This project tries to explore effective schemes to reduce high false alarm rates in the existing technologies.

Project 2: Wireless sensor network security. Wireless sensor network is regarded as the most influencing technology in the 21st century. However, security is a major issue in sensor network as it is normally deployed in a hostile environment and also it cannot afford many existing security mechanisms due to energy issue. This project will explore energy efficient security schemes especially on cryptography key generation and distribution.


» Developmental Systems and Machine Learning

SEIT AcademicsDr Kathryn MerrickDr Kamran Shafi Dr Amitay Isaacs Dr Michael BarlowDr Chris LokanA/Prof Valeri Ougrinovski Prof Hussein AbbassDr Jen Badham (Visiting Fellow)

SEIT Postgraduate StudentsMrs Medria HardhienataMr Muhummad Shoaib Khan NiaziMr Essam Soliman Yousseif Mohamed DebieMs Bing Wang

Other Collaborators


Dr Ning Gu

University of Maryland

Dr Mary Lou Maher

University of Sydney

Dr Xiangyu Wang

Research DescriptionTopics studied by the Developmental Systems and Machine Learning group lie at the intersection of cognitive science, developmental robotics, virtual worlds and machine learning research. Cognitive science is the interdisciplinary study of how information used during perception, language, reasoning, motivation and emotion, is represented and processed, either in a human or animal, or by a machine (specifically a computer in our case). Developmental robotics and character animation in virtual worlds are application areas that use principles of cognitive and developmental sciences to build artificial systems capable of ontogenetic development. Such systems initially have little or no domain-specific knowledge or skills in their “infant” stage, but are equipped with generic reasoning mechanisms that permit them to acquire such knowledge and skills through interaction with their environment as they mature to an “adult” stage.

Researcher areas of interest to the Developmental Systems and Machine Learning group include, but are not limited to, reinforcement learning, neural networks, data mining, ensemble learning and learning classifier systems, as well as naturally inspired cognitive models, genetic and evolutionary systems. Applications include robotics, digital characters in virtual worlds, intelligent environments, network intrusion detection and social networks.

Highlights in 2011 include the renovation of the Developmental Robotics Laboratory, commencement of a fortnightly research meeting in conjunction with the Virtual Environments and Simulation Laboratory and the welcoming of two new postgraduate students.

Computational Models of Achievement, Affiliation and Power Motivation for Artificial SystemsIn the area of cognitive science and developmental systems, 2011 saw publication of a number of computational models of motivation for use in of agent-based or robotic applications. Computational models of the ‘influential trio’: achievement, power and affiliation motivation were developed for artificial systems. The new models have been validated in agent-based simulations of well known experiments from human psychology, including the ring-toss experiment, roulette experiment and a prisoner’s dilemma experiment. Results show that our new models permit the design of agents with statistically similar decision-making properties to humans under certain cooperative, competitive and risk-taking conditions. These results were published in the Adaptive Behavior journal and presented at the International Conference on Autonomous Agents and Multiagent Systems in 2011. In 2011 these models were studied for single-shot decision making. In 2012 this work will continue with a focus on iterative decision making.

Reasoning in the Absence of GoalsIn creative industries such as design and research it is common to reason about ‘problem-finding’ before tasks or goals can be established. Problem-finding may also continue throughout the problem-solving process, so achieving goals may be an ongoing process of discovery as well as iterative improvement and refinement. This project considers the design of cognitive systems with complementary processes for both problem-finding and problem-solving. In 2011 we reviewed a range of approaches that may complement goal-directed reasoning when an artificial system does not or cannot know precisely what it is looking for. We argue that there is a spectrum of approaches that can be used for reasoning in the absence of goals, which make progressively weaker assumptions about the definition and presence goals, and that goal-oriented behavior can be an intermediate result of problem-finding, rather than as a starting point for problem-solving. In 2011 this project supported a Chief of Defence Force Student Project, resulting in a publication at the AAAI Fall Symposium on Advances in Cognitive Systems.


Task Allocation in Multi-Agent Systems Using Models of Motivation and Leadership This PhD project focuses on how to improve the efficiency of multi-agent coordination, so that coordination problems can be solved in a more reliable way. To address one aspect of this issue, this project proposes a new method that endows agents with models of motivation and leadership to aid agents’ coordination. Initially, we study the model for solving a task allocation problem. The outcomes of this project in 2011 include a new approach named Motivated Particle Swarm Optimization (MPSO) algorithm that embeds the agents with a model of motivation and leadership for coordination. This approach considers the task allocation problem in the case where there is a small number of agents initialized at a single point. The objective is to achieve an even distribution of agents to tasks. The proposed approach uses the Particle Swarm Optimization algorithm with a ring neighborhood topology as a foundation and incorporates computational models of motivation to achieve the goals of task allocation more effectively. The results of the numerical experiments show that compared to the lbest PSO algorithm using a ring topology, first, the proposed method increases the number of tasks discovered. Secondly, the number of tasks to which the agents are allocated increases. Thirdly, the agents distribute themselves more evenly among the tasks. In 2012 this work will continue to adjust some critical parameters and other possible variations of the number of each type of agent to increase both the role of leader and the performance of the new proposed method by using an optimization strategy. Other potential work that will be done in 2012 is to implement the Nearest Neighbors methods where the selection of neighborhoods is done dynamically, based on the distance between agents in the search space.

Extending the Data Mining Capabilities of Learning Classifier Systems to High-Dimensional Search Spaces and Limited Training DataLearning classifier systems are emerging genetics-based machine learning techniques that have recently shown a high degree of competence on a variety of data mining problems. One critical problem that is highlighted in recent research is the stalling of the genetic search when facing with high dimensional problems. Another problem is their performance degradation when dealing with limited training data. This latter problem has not been analysed adequately in the literature. This PhD project is addressing these two problems independently and in combination. A literature review has been conducted in the area of learning classifier systems and a number of experiments conducted to systematically diagnose the key issues that cause Learning Classifier Systems to perform poorly under the two scenarios. This work will continue in 2012 to formalise the learning bounds under the two problems and develop solutions to deal with issues highlighted by our analysis.

Creative Search Systems and Hypothesis GenerationThis PhD project is investigating the design of search systems that can explore an environment defined by a batch of input data, and find patterns hidden in the environment. This intelligent system should be capable of learning to improve its search ability over time. In 2011 this project has made definitions of the expected searching system, as well as performance measures of an improving search system from several different aspects. A literature review in the areas of hypothesis generation, rule mining and machine learning has also been conducted.

Motivated Agents for Modelling Social Network Crime Still in the computer security domain, this Masters by research project is developing agent-based simulations of social network crime – with specific focus on spam and the role of human motivation in generating and detecting spam. To reduce the potential threats and risks to social networking sites (SNSs), we require an understanding of the contributing factors. In 2011 the outcomes of this project include a study and model of SNSs and their user types. This division will provide us with a base to understanding the culture and business model of SNSs and the behavior of their users. It is also necessary to understand the current tactics used by cybercriminals on SNSs, future threats and challenges faced by SNSs and ways to deal with those threats and challenges. Generally SNSs can be categorised on the basis of the services they are offering and level of authority they give to their users. Furthermore, users can be categorised on the basis of their motives for using SNSs. This permits us to identify users who can impose threats for other users as well as for the SNS itself. In 2011 this project will continue to validate our model through a study of user behavior on existing SNSs including Facebook and Twitter.


Case Studies Using Multiuser Virtual Worlds as an Innovative Platform for Collaborative Design

This project investigated the innovative use of emerging multiuser virtual world technologies for supporting human-human collaboration and human-computer co-creativity in design. The project defined a series of conceptual technology spaces that describe the different aspects of virtual worlds that make them useful as platforms for certain types of collaborative design. The primary spaces were: design tools for modelling new artefacts, support for communication, and the ability to incorporate artificial models of cognitive design processes. Secondary spaces include the network and graphics technology, educational/tutorial systems and motivational systems. In order to support the conceptual technology spaces for multiuser virtual worlds, a number of case studies were conducted and examined in the field of collaborative design using multiuser virtual worlds. Analysis of these case studies reveals the current strengths and limitations of multiuser virtual worlds for supporting human-human collaboration and human-computer co-creativity in design activities. In addition they suggest extensions of virtual world design systems beyond small-scale collaborative design towards large-scale mass participation and collective design. This work was published in the Journal of Information Technology in Construction, Special Issue on Use of Virtual World Technology in Architecture, Engineering and Construction.

Supporting Collective Intelligence for Design in Virtual WorldsThis project analysed virtual worlds with reference to the technological facets that can support of collective intelligence in design. These include graphical simulation tools, communication, design and modelling tools, artificial intelligence, network structure, persistent object-oriented infrastructure, economy, governance and user presence and interaction. We discuss how these facets support the design, communication, motivational and educational requirements of collective intelligence applications, and how these world facets can be adopted for supporting collective design by drawing analogues to gaming concepts such as level systems, quests or plot and achievement/reward systems. We argue that there is a mapping between these game elements and the requirements to achieve collective intelligence in design. In 2011 this work resulted in a case study of Lego Universe, to validate the technology facets defined above.

We discuss the potential of Lego Universe or similar tools to move design beyond the individual and small-scale professional design teams to harness large-scale collective design through mass participation. This was published in CAADFutures 2011.

Computational Creativity and Procedural Content Generation in Computer GamesWith rapid growth in both production costs and player populations over the last decade, the computer games industry is facing new scalability challenges in game design and content generation. The application of computers to these tasks – called procedural content generation – has the potential to reduce the time, cost and labour required to produce games. A range of generative algorithms have so far been proposed for procedural content generation. However, automated game design requires not only the ability to generate content, but also the ability to judge and ensure the novelty, quality and cultural value of generated content. This includes factors such as the surprise-value of generated content as well as the usefulness of content in the context of a particular game design. Studies of human designers have identified that the ability to generate artefacts that are novel, surprising, useful and valuable are facets of the human cognitive capacity for creativity. This suggests that computational models of creativity may be an important consideration for developing tools that can aid in or automate design processes. However such cognitive models have not yet been widely considered for use in procedural content generation for games. This project has developed a framework for procedural content generation systems that use computational models of creativity as a part of the generative process. A software system has been implemented that combines the generative shape grammar formalism with a model of creativity based on the Wundt curve to select new designs that are similar-yet-different to existing human designs. The approach aims to capture the usefulness and value of existing designs while introducing novel and surprising variations. The system incorporates a metric that permits generated designs to be evaluated in terms of both their similarity to high quality human designs and their creative novelty


» Engineering in Medicine

SEIT AcademicsA/Prof Mark Pickering Dr Andrew Lambert Dr Murat Tahtali

SEIT Postgraduate StudentsAbdullah Al Muhit Md. Nazmul Haque Rafiqul Islam Md Abdullah Masum Masuma Akter Md Omar Khyam Sajib Kumar Saha

SEIT Research StaffDr Moyuresh Biswas

Other Collaborators

Trauma and Orthopaedic Research Unit, The Canberra Hospital

A/Prof Paul Smith A/Prof Jennie Scarvell Dr Tom Ward

Research DescriptionThere are many aspects of engineering which can be applied to improve medical technology. The current focus of the Engineering in Medicine group is the application of image and signal processing techniques to aspects of orthopaedic medicine. In particular, the research focus has been on the development of new ways to measure the three dimensional motion of bones in a joint while the patient is performing everyday functional tasks. The measurement of how the bones move can provide valuable information for many aspects of the treatment of injured joints. For example, an analysis of pre- and post-operative motion on patients undergoing total knee replacements can provide valuable feedback to the designers and manufacturers of knee implants. The ability to accurately measure joint motion can also be used in planning rehabilitation treatments targeting particular muscle groups to bring the joint motion back into the normal range after injury or reconstructive surgery. The research of the group has focussed on developing improved imaging techniques to fuse 2D motion data available from standard hospital imaging equipment with 3D CT data and alternative non-invasive techniques for kinematic analysis using ultrasound.

Precision Assessment of B-mode Ultrasound for Non-Invasive Motion Analysis of Knee JointsVisualization of the motion trajectories (kinematics) of individual bones in a knee joint gives significant insights to orthopaedic surgeons for the analysis of knee replacement and reconstruction surgery. A major focus of the orthopaedic research community is to restore normal motion to the knee joint after a total knee replacement or surgery to repair ruptured ligaments. Kinematic analysis has several important applications including: providing valuable information during knee replacement surgery, enabling the comparison between the motion of normal and abnormal knees for designing artificial knee components, investigating how abnormal motion influences the resulting early wear of the components in an artificial knee joint, evaluating different types of techniques for ligament reconstruction, identifying pain and wear inducing motion and developing therapeutic strategies to prevent this motion in its early stages. Currently the standard way to measure the motion with enough accuracy is by implanting tantalum beads in the bones prior to imaging using X-ray equipment. However this technique is invasive and exposure to ionizing radiation imposes a significant cancer risk. Moreover, during the procedure the patient cannot perform normal everyday activities due to their confinement to the limited field of view of the X-ray equipment. Recently we proposed a novel non-invasive approach to measure knee motion using non-invasive 2D B-mode ultrasound and 2D/2D image registration. Results from this work show a maximum deviation of 0.51 mm and 0.42 mm from the true displacements for the registered horizontal and vertical motion parameters respectively. The standard deviation of the error between the true and measured translations was 0.145 mm and 0.151 mm for the horizontal and vertical translations respectively. These precision results compare favourably with the current clinical standard for kinematic analysis (RSA) which has a reported precision of 0.25 mm.

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A New Similarity Measure for Multi-Modal Image Registration Image registration is the process of spatially aligning one image to another. Registration algorithms consist of two main components: a similarity measure and an optimization technique. For images captured using the same sensor the similarity measure used is typically the sum-of-the-squared difference (SSD) between the two images. However, if the images to be registered are captured using different sensors, a linear relationship between the pixels cannot be assumed and the SSD will not be a true indication of the spatial alignment of the images. In such cases, a multi-modal similarity measure is required such as Mutual Information (MI), Cross-Correlation or Correlation Ratio. These similarity measures quantify the relationship between two images using probability distributions rather than intensity values. Registration is often required for medical images of the same patient captured using different imaging modalities such as MRI, CT and PET. In this project, a new multi-modal similarity measure was proposed that was based on calculating the sum-of-conditional variances from the joint histogram of the two images to be registered. The formulation of this new similarity measure allows the standard Gauss-Newton optimization procedure to be used. To evaluate the performance of the new similarity measure, we compared the algorithm with the approach developed by Thevenaz and Unser for the MI similarity measure. Figure 2 (a) shows the success rate of the two algorithms and Figure 2 (b) shows the average registration error at each iteration over the successful registration attempts performed by the two algorithms. These results show that our new approach is more accurate and robust than the most common and best performing alternative.

Super Resolution of 3D MRI Images Using a Gaussian Scale Mixture Model ConstraintMagnetic resonance imaging (MRI) is used to capture images of the human body or parts of the body for clinical purposes. An MRI scanner is capable of acquiring 2D cross-sectional images of the human body from any orientation. It is a non-invasive method and uses strong magnetic fields and non-ionizing radiation in the radio frequency range. In multi-slice magnetic resonance imaging (MRI) the resolution in the slice direction is usually reduced to allow faster acquisition times and to reduce the amount of noise in each 2-D slice. In this project, a novel image super resolution (SR) algorithm was developed to improve the resolution of the 3D MRI volumes in the slice direction. The proposed SR algorithm uses a complex wavelet-based de-blurring approach with a Gaussian scale mixture model sparseness constraint. The algorithm takes several multi-slice volumes of the same anatomical region captured at different angles and combines these low-resolution images together to form a single 3D volume with much higher resolution in the slice direction. Our results showed that the 3D volumes reconstructed using this approach have higher quality than volumes produced by the best previously proposed approaches.

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»Maximum-Entropy Analyses of Flow Systems

SEIT AcademicsDr Robert Niven

Other Collaborators

Australian National University, Australia

Prof. Roderick DewarDr Charley Lineweaver

CNRS Poitiers, France

Prof. Bernd Noack

CSIRO / University of Western Australia, Australia

Prof. Klaus Regenauer-Lieb

University of Hiroshima, Japan

Dr Hisashi Ozawa

Research DescriptionThis theme concerns the concept of entropy, a measure of the disorder of a system, and one of the most profound but least understood discoveries of human knowledge. As shown by Boltzmann, entropy is based on probabilistic (combinatorial) concepts, providing the tool to predict the most probable state of a system. Although this idea is widely applied in statistical mechanics and thermodynamics, the fundamental concept has far broader power of application, being applicable to all systems of probabilistic character. The potential for new methods for analysis of many scientific, engineering and human systems - to replace a variety of empirical and semi-theoretical methods - is especially strong.

In this project, the generic maximum entropy method (“MaxEnt”) developed by Jaynes in 1957 was used to infer the state of several different types of probabilistic systems. Research was undertaken on several interrelated projects, as listed below.

Maximum-Entropy Closure of Steady-State Fluid Flow SystemsThis project involves the prediction of the steady state of a non-equilibrium flow system, for which three approaches have been developed:

1. During a 3-month visit by Dr Niven to the Institut Pprime fluid mechanics laboratory of the Centre National de la Recherche Scientifique (CNRS) / Université de Poitiers / ENSMA, Poitiers, France, hosted by Prof. Bernd Noack, a new approach was developed for a Galerkin model of an incompressible periodic cylinder wake, which employs a MaxEnt method for system closure. The analysis predicts mean amplitude values and modal energy levels in good agreement with direct Navier-Stokes (DNS) simulation, in effect supplanting the need for DNS analysis. In addition, it provides an analytical equation for the modal energy distribution. The authors believe this work to be a major research achievement, which could pave the way for a new, scientifically defensible turbulence closure method without the need for artificial constructs (such as the eddy viscosity). The research findings have been summarised in a 50-page manuscript which has just been accepted for publication (Noack & Niven, in press). Dr Niven will host a reciprocal visit by Prof. Noack to UNSW Canberra during April 2012, enabling accelerated research on this theme.

2. A MaxEnt analysis of an infinitesimal element within a control volume, using an entropy function defined on the set of fluxes through the element. In specific circumstances, this analysis provides a derivation of the “maximum entropy production” (MaxEP) principle, currently used as an empirical heuristic to predict the steady state of many non-equilibrium flow systems. This research unites all fields which involve non-linear flow phenomena (e.g. turbulent fluid flow, convective heat transfer, biochemical degradation). Building on a major theoretical foundational work published in 2009, this research led to one further refereed conference / book chapter publication during 2011 (Niven, in press 2).

3. A MaxEnt analysis of fluid flow in a simple internal flow (such as flow in a pipe) was also developed. During a 1 month visit by Dr Ali Ghaderi of REC Wafer Norway AS, Porsgrunn, Norway, hosted by Dr Niven of the School, the body of previous research on this topic by C.L. Chiu was extended into full three-dimensional analysis, involving probability density and entropy functions defined on phase space coordinates. This research was also integrated with a new approach to the choice of prior probabilities within MaxEnt, developed by Dr Ghaderi. This work is currently being further developed and will soon be summarised for publication.


Maximum Entropy and Maximum Entropy Production Analyses of the Earth and Extrasolar Climate SystemsEmploying the MaxEnt method, a simple framework was developed by Dr Niven to enable the synthesis of multiple climate models of the Earth climate system. Two approaches were developed, based on sets of individual climate models or ensembles of models, analogous to the microcanonical and canonical ensembles of thermodynamics. The primary advantage of these approaches is the ability to directly predict the optimum (most probable) conditions of a suite of models, without the need for calculation of the entire set. A connection was also made to cost-benefit analysis within (any) modelling framework. This research led to one publication in 2011 (Niven, in press 1).

Research was conducted in collaboration with Dr Hisashi Ozawa, University of Hiroshima, Japan, on applications of the MaxEP principle to the analysis of planetary climate systems, with specific application to solar and extrasolar planets. This work is currently being summarised for publication.

This research theme also involved a number of invited seminars to research groups in the Australia, Canada, France and the UK, including a keynote presentation by Dr Niven to the 31st International Workshop on Bayesian Inference and Maximum Entropy Methods in Science and Engineering, Waterloo, Canada, 10-15 July 2011. Dr Niven was also co-host of the Maximum Entropy Production Workshop, Australian National University, Canberra, Australia, 12-14 September 2011. Dr Niven and collaborators are currently organising a further international conference on MaxEP and related principles, to be held in Australia in December 2012.


» Geotechnical Engineering and Pavement Geotechnics

SEIT AcademicsA/Professor Robert LoDr Rajah Gnanendran

SEIT Postgraduate StudentsMr Abdul Lahil Baki Mr Rajibul KarimMr Dalim PaulMr. Ariful IslamMr. Ohiduz ZamanMr. Jiajun ZhangMr. Alam IftekharMr. Nurul IslamMr. Mathanraj Theivakularatnam

Other Collaborators

Road and Traffic Authority (RTA), NSW

Queensland Department of Transport and Main Roads

SafeLink Joint Venture

Maccaferri Australia Pty Ltd

Nehemiah Reinforced soil, KL and Syd.

Nanyang Technological University, Singapore

University of Nottingham, UK

Centre of Research and Professional Development, HK

Indian Institute of Technology, Madras, India

Swinburne University of Technology, Melbourne

Research DescriptionGeotechnical engineering is a vital part of civil engineering that deals with the engineering aspects of soils and rocks which are collectively referred as geomaterials. The designs of every building, bridge or any other civil engineering structure built on the ground must give due consideration to the underlying and/or surrounding geomaterials. Among the geomaterials, soft clays are widely found in Australia and around the world and they are problematic for constructing civil engineering structures due to their low shear strength, high water content and large time dependent deformation characteristics. However, due to rapid growth of infrastructure and transpiration development and environmental considerations, the necessity of constructing road embankments and other structures on such soft soils is common. Excessive ground deformations, which is a common scenario in such problematic soils, causes severe damages to pavements and other related structures and research in soft soil engineering form an important part of our research activities. Another principal area of our research is concerning the instability and liquefaction potential of sandy soils under cyclic or dynamic loading conditions such as earthquakes.

Soils being weak in tension, different stabilization methods are adopted for overcoming design and construction problems involving them (e.g. steep slopes, retaining walls). The use of geosynthetic reinforcement has been advocated recently to be an economical method for stabilising such soil structures. However, design of reinforced soil structures depend on the interaction behaviour between the soil and the reinforcement and research is under way in this area also.

Road pavements are constructed with geomaterials and hence their designs are influenced by the engineering behaviour of pertinent geomaterials under the influence of the environmental and traffic loading conditions. Thousands of kilometers of granular (gravel) base pavements (i.e. pavements without a structural asphalt layer) exist in Australia and a number of these pavements fail prematurely. Important research initiatives such as light stabilization of granular materials using cement blended with slag or flyash and incorporating unsaturated soil mechanics principles to characterise the behaviour of pavement materials are undertaken by our group to address this problem with the objective of developing innovative solutions.


Soft clay engineeringRoad embankments constructed on very soft clay along the east coast of Australia may manifest very high settlement in the order of 1m or more, even for moderate embankment height. The design and contractual issues of such embankments are further complicated if the soft clay manifests creep and/or “sensitive” behaviour. Extensive research is being carried out in this area, supported both in-cash and in-kind by RTA, NSW.

Currently our research is focussed on the prediction of long term performance of soft soil behaviour using the new elasto-viscoplastic (EVP) model developed recently incorporating nonlinear variation of the creep coefficient and a newly proposed yield surface (Karim, Manivannan, Gnanendran and Lo, S-C. R. (2011). The predictive capability of this model has been assessed by analyzing the long term performance of Leneghans embankment and it has been found to be superior compared to elasto plastic and other EVP models (see Karim et al. 2011 and Manivannan, Karim, Gnanendran and Lo (2011) for further details).

When the application of traditional ground improvement techniques such as surcharge preloading, wick drains and vacuum preloading are not appropriate for a particular situation, innovative techniques such as electro-osmosis needs to be considered. Though the effectiveness of electro-osmosis has been widely demonstrated in many field applications, geotechnical engineers are still hesitant to apply electro-osmosis due to unveiled effects such as electro-chemical effects which could not be accounted for in the design.

The design of an electro-osmotic triaxial testing apparatus (see Fig. 1 below) suitable for electro-osmotic treatment of soft clays and for measuring the electro-osmotic permeability, generated pore water pressure and a testing procedure that account the contribution of electro-chemical changes in the improvement of soil properties was developed by Jeyakanthan, Gnanendran and Lo (2011).

Figure 1. Photographs of experimental setup for electro-osmotic treatment and the newly developed top and bottom caps with electrodes (from Jeyakanthan, Gnanendran and Lo 2011)


Liquefaction and instability of sand with finesWe continued our research in this area, which has been ongoing for a number of years and in collaboration with Nanyang Technological University, Singapore, and University of Nottingham, UK. We demonstrated that a single relationship between equivalent granular state parameter and instability stress ratio can be used for sand with a range of fines content, where instability stresses ratio is the effective stress ratio that defines triggering of static liquefaction (see Fig. 2 below). This relationship is referred to as the instability curve as static liquefaction, in the context of continuum mechanics is instability under undrained loading. The instability curve can also be used to predict the triggering of cyclic liquefaction of loose sand with fines, here the term loose is defined by a clearly positive equivalent granular state parameter (higher than the 0.045, the experimental error in its determination).

Pullout resistance of soil reinforcement An extensive experimental study that involved the testing of two types of reinforcement with the same source of select fill was completed this year. The two types of reinforcements are: ribbed steel strip and steel ladder. The select fill used contain ~17% fines and were obtained from a borrow area earmarked for an actual construction project. Two unexpected findings: The bearing resistance was mobilised at 100% to 200% of bar diameter, and N

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increased at overburden stress less than 60 kPa (see Fig 3). The former leads us to question whether, in addition to bearing capacity analogy, there are other mechanisms at play. The latter suggests the presence of constrained dilatancy.

Lightly stabilised granular materials Australia has one of the largest road networks in the world and much of this network is over 40 years old, which is typically the design life of a pavement. Hence, each year, significant amount of roads require rehabilitation or reconstruction to sustain the road infrastructure at an acceptable level. Moreover, many of these roads are being widened and reconstructed to cater the rapid growth of road freight and traffic. Along with this growth, increase in axle loads from heavier vehicles such as B-doubles and road trains is also taking pace, which substantially increases the deterioration rates of existing pavements. An overwhelming challenge is, therefore, how we can cleverly engineer the construction of new or reconstruction/rehabilitation of existing road pavements in an environmentally sustainable and cost-effective way.

Pavements are generally constructed with granular materials compacted in layers over the natural road bed material referred to as the subgrade. Engineering characteristics of granular materials could be improved dramatically by mixing Portland cement to them which is referred as stabilization but the cost of cement is quite high and hence it is not always practiced. An economical and environmentally friendly method of stabilizing them would be to use binders such as blends of slag and lime or flyash and Portland cement in small quantities which are referred to as “light stabilization”.

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We continued with the laboratory investigation on the characterisation of a freshly quarried granular base material lightly stabilised with slag-lime cementitious binder involving unconfined compression (UC) testing and monotonic as well as cyclic load Indirect Diametrical Tensile (IDT) testing, both with internal displacement measurements. The UC test investigation involved the determination of the unconfined compressive strength (UCS) and four different types of stiffness moduli from both internal and external displacement measurements. The IDT testing included the determination of IDT strength as well as the static and dynamic stiffness moduli of the lightly stabilised granular base material from monotonic and cyclic load IDT testing.

The major distress modes involving cementitiously stabilized granular materials in road pavements are fatigue cracking and permanent deformation and they are being investigated through pavement model testing. In particular, the pavement model testing method and its suitability for determining the stiffness modulus, fatigue and permanent deformation properties of a pavement structure constructed with a cementitiously stabilized granular base layer and a clay subgrade layer was investigated.

A new laboratory pavement model testing setup with extensive instrumentations to measure soil deformations and strains was developed (see Fig. 4). The suitability of this testing arrangement for determining the stiffness, fatigue and permanent deformation characteristics of a pavement structure was examined by studying the characteristics of a granular base materials stabilized with 1.5 % general blend (GB) cement-flyash and of a clay subgrade material. The test was continued at a frequency of 3 Hz up to 8 millions load cycles and measured horizontal tensile strain at the bottom of the stabilised base layer was used to determine the fatigue life of the stabilised layer (see Fig. 5 for typical results). This study indicates that the deformation and strain measurement setups developed for pavement model testing is suitable for undertaking accelerated cyclic load pavement model tests to determine the stiffness, fatigue and permanent deformation properties of the materials reliably (see Gnanandran et al. 2011).

Figure 4. Accelerated Pavement Model Test on cemented base and clay subgrade(from Gnanendran, Piratheepan, et al. 2011)

Figure 5. Typical vertical deformation and horizontal strain responses obtained from accalerated pavement model testing (from Gnanendran, Piratheepan, et al. 2011)


Pavement materials as unsaturated soilWe started our preliminary study into the influence of fines on unbound granular base materials, with a particular focus on developing a unified framework (based on unsaturated soil mechanics) to explain the often divergent findings reported in literature. Increase in fines changes the maximum dry density (MDD), optimum moisture content and therefore its effect cannot be easily isolated. More importantly it also changes the soil water characteristic Curves (SWCC) as illustrated in Fig. 6. This means that no matter how we make the comparison, the initial matric will be increased. However there may also be an opposite effect, the deformability may be reduced by the increase of fines as illustrated in Fig. 7.

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» High Frequency Engineering

SEIT AcademicsDr Greg MilfordDr Robin DunbarFLTLT Matt Gibbons (Visiting Fellow)

SEIT Postgraduate StudentsMs Rajpreet Kaur GulatiMs Le Chen

Other Collaborators


Dr Ilya Shadrivov

Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino

Dr Ladislau Matekovits

Research DescriptionThe High Frequency Engineering Research group conducts theoretical and applied research in the fields of antennas, microwave and millimetre wave electronics, and computational electromagnetics. The following paragraphs summarise the group’s activities in 2011.

Equivalent Circuit Modeling of Planar Structures

The left-handed propagation behaviour of artificial metamaterial structures offers a new paradigm for electromagnetic device design. Transmission line metamaterials, or composite right-left hand transmission lines (CRLH TL) have been shown to achieve wider bandwidth and lower losses than resonance based left-handed structures, and a range of wave-guiding and radiation applications have been demonstrated. The analysis and design of CRLH TL structures is greatly facilitated if an equivalent circuit model is available for the CRLH unit cell. Such equivalent circuits enable derivation of closed form expressions for the key performance characteristics of the CRLH structure (such as cutoff frequency values, dispersion behaviour and Bloch impedance). In this work we demonstrate how a direct solver approach can be used to develop a unit cell equivalent circuit from knowledge of a single unit cell‘s frequency response.

Figure 1.1 illustrates a single CRLH unit cell consisting of a pair of series-connected interdigital capacitors (IDC) and shunt-connected inductors (SI), implemented in Grounded Coplanar Waveguide (GCPW). Also shown in this figure are vias for connecting the top and bottom ground planes of the GCPW structure, thereby suppressing parasitic higher-order modes in the GCPW.

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techniques to directly solve the over-determined matrix equation formed by comparing the series and shunt arm immittances in Figure 1.2 with the equivalent 2-port ABCD parameter terms, where the latter are calculated from the measured or simulated S-parameter data values over a range of frequencies.

Figure 1.1 Top view (above) and photo (below) of a single stage interdigital capacitor, shunt inductor (IDC-SI) unit cell implemented in Grounded Coplanar Waveguide. Vias are used to connect top and bottom ground planes

Figure 1.2 Equivalent circuit model for the IDC-SI unit cell of Fig. 1.1, excluding feed-lines and coaxial connectors.


To evaluate the performance of the equivalent circuit extraction process, both Network Analyser measurements and full-wave simulation data (using Agilent‘s ADS Method of Moments solver Momentum) were generated for the structure in Figure 1.1. Figure 1.3 compares the frequency responses obtained using the extracted equivalent circuit models with the measured and simulated data. In both cases very good agreement between the respective model and original S-parameter frequency responses was obtained, up to the right-hand cutoff frequency around 10 GHz.

The S-parameter behaviour observed in the measured and simulated responses above 10 GHz is due to (undesirable) non-CRLH unit cell behaviour, and reflects a limitation of the IDC-SI structure for CRLH unit cell implementation. Also, the close agreement between the measured and simulated responses indicates accurate full-wave modeling of the structure. The use of this direct solver approach provides a computationally efficient alternative to iterative or optimisation-based approaches, and is more accurate than existing approximate methods for calculating equivalent circuit component values.

Width-Modulated Periodic StructuresThe demand for real-time reconfigurable radio frequency devices for applications such as cognitive radio and smart antennas has stimulated much research into new approaches for adjustable component design. Generally, such multi-band, multi-purpose circuits require some active device for switching or tuning the desired transfer function of an associated passive device. Additionally, power consumption is an important consideration with portable devices, hence low power consumption by active devices and low loss passive circuits are desirable. In this work we investigate varactor diode tuning of a modulated width microstrip transmission line to produce a multi-band wave guiding structure with predictable frequency response charateristics. This approach has the advantages of no power supply consumption by the active devices (ie. reverse biased varactor diodes), and tunability of the inherent multi-band behaviour of the periodic microstrip structure.

Firstly we validate the approach taken to efficiently simulate the periodic microstrip structure, which is described as follows. Figure 2.1 illustrates the variation of the effective permittivity of a microstrip line with line width, while Figure 2.2 illustrates the corresponding width profile along the axis of the microstrip line to produce a sinusoidal variation in effective permittivity of +/- Mu = 0.17 about an average value of 6.671, over the length of a modulated width unit cell of length of 7.5mm. Fig 2.3 illustrates the fabricated circuit consisting of a cascade of 20 such unit cells.

The frequency response of the modulated width line of Figure 2.3 is illustrated in Figure 2.4, showing a low-pass response with a cutoff frequency of about 4 GHz, and multiple band-pass responses from 10 GHz upwards. Also shown in Figure 2.4 is a simulated frequency response obtained by performing a full-wave (Method of Moments) simulation of a single unit cell (Figure 2.2(b)), with access ports defined at the two narrower ends of the structure. This is followed by a circuit simulation of a cascade of 20 identical 2-port networks, where the S-parameters for these 2-ports are linked to the full-wave simulation data. A layout artwork is then generated from the circuit schematic for subsequent fabrication. Good agreement between measured and simulated data can be observed in Figure 2.4, confirming that the response of the periodic cascade of unit cells can be calculated from knowledge of a single unit cell‘s 2-port characteristics.

Secondly, this co-simulation approach is used to predict the performance of the active (tunable) transmission line structure formed by inserting shunt-connected varactor diodes at one end of each of the modulated width unit cells. At this position the microstrip line is the narrowest (highest impedance), maximising the effect of the shunt-connected varactor reactances.

Figure 1.3 Comparison between the frequency response reproduced from the extracted equivalent circuit model with the measured (above) and full-wave simulated (below) frequency responses, showing good agreement up to the right-hand cutoff frequency.


Figure 2.5 illustrates the simulated reflection and transmission S-parameter and extracted dispersion responses for the 20 stage circuit, for two different bias voltages. These results show virtually no change in performance over the low-pass region, but tunability of the band-pass regions. Although the circuit of Figure 2.3 has a length of 150mm, this approach could be used to produce a much smaller device suited to applications requiring a fixed lower passband and adaptable upper passbands. In addition the co-simulation approach offers a computationally efficient approach to periodic structure analysis.

Figure 2.1 Variation of effective permittivity Ԑeff

of the microstrip line with line width. Vertical dashed lines indicate Ԑ

eff = 5.537, 6.671, 7.805,

being the minimum, average and maximum values of Ԑ

eff (substrate properties: Ԑ

r = 10.2

with thickness of 0.025 inch).

Figure 2.3 Photo of 20-stage structure, including a 50 Ohm through-line for calibration purposes. Overall length is 150mm.

Figure 2.2 Modulated width unit cell: (a) width contour using data in Fig. 2.1 to achieve the desired sinusoidal variation of effective permittivity, and (b) top vitew of 7.5mm long by approximately 4mm wide varying width unit cell, showing a finite element mesh for full-wave simulation

a

b


Nonlinear Transmission Line MetamatrialsIncorporation of nonlinear components into a CRLH TL produces a nonlinear (NL) CRLH TL. These structures has been shown to exhibit a wide range of tunable nonlinear propagation phenomena due to the interaction of the dispersion characteristics of the CRLH TL with the nonlinear elements. Such circuits produce harmonic generation, parametric amplification and oscillation, but also exhibited unstable behaviour as the bias and input drive conditions are varied.

Figure 3.1 illustrates a 20 stage NL CRLH TL circuit where series connected varactor diodes in each unit cell are used to produce the nonlinearity. Figure 3.2 illustrates this circuit’s dispersion characteristic. The varactor diodes can be tuned for a balanced bandpass response in which case low loss propagation occurs from left to right-handed regions with no bandgap. Since a wave guiding structure can function as a leaky wave antenna (LWA) if the guided wave’s propagation coefficient is less than the free-space wave number, this dispersion characteristic predicts LWA operation for frequencies within the “light cone” or fast wave region of Figure 3.2.

In this work we show how the parametric frequencies generated by the NL CRLH TL under large signal drive conditions can be controlled, such that at least one parametric frequency (frequency f

2) lies

within the fast wave region of Figure 3.2, leading to LWA radiation of this parametric frequency. Figure 3.3 illustrates the measurement configuration for characterising the received spectra as a function of azimuth rotation angle of the NL CRLH circuit. Figure 3.4 shows an example of the measured spectra at a particular azimuth position, for three different pump frequencies as indicated. Although the pump power levels are significantly greater than the two parametric frequency power levels in the circuit, the measured spectra show much greater f

2 parametric

frequency power levels compared to the lower parametric frequency f

1, and comparable f

2 and

pump power levels, indicating much more efficient radiation of f

2 frequency components.

Figure 2.4 Reflection (top) and transmission (bottom) coefficient of the 20 stage periodic structure of Fig. 2.3. Very good agreement is observed between measured and simulated responses.

Figure 2.5 Frequency response of the varactor loaded periodic structure, for varactor bias voltages of -10V and -3V, illustrating (above) fixed low-pass pass-band and tunable band-pass pass-bands, and (below) dispersion characteristic indicating the slow wave behaviour of the varactor loaded 20 stage periodic structure

Figure 3.1 20 stage NL CRLH circuit using varactor diode nonlinearites. Decoupled DC varactor bias voltages are supplied with the circuitry to the upper part of the circuit, with coaxial connectors at the input and output port.


The variation with azimuth of the f2 parametric

frequency component is illustrated in Figure 3.5, where the amplitudes are normalised to the peak value for each azimuth scan. Most of the azimuth scans show a distinct centralised main lobe, with a beam-width of around 50 degrees, consistent with a ‘rule of thumb’ half power beam-width calculation of λ/D where D is the length of the NL CRLH TL circuit (91mm). The beam center position varies with the f

2

frequency, increasing in azimuth as the parametric frequency f

2 increases.

This frequency scanning behaviour is consistent with theoretical predictions, as can be seen in Figure 3.6, showing the variation of the LWA scan angle with frequency, using both the circuit simulated and measured dispersion data of Figure 3.2, superimposed with asterisks indicating the beam peak positions of Figure 3.5. The observed beam center values for the left-hand pass-band, that is for f

2 less

than 3.80 GHz (transition frequency), follow the same trend as the predicted scan angles obtained using either the simulated or measured data. However this is not the case for right-hand f

2 values, instead these

frequencies fit more closely to a ‘flipped’ scan angle response, indicated by the dotted curves in Figure 3.6, consistent with a reversal of the propagation direction between LH and RH regions for the f

2

frequency. The variation of the main lobe direction appears consistent with leaky wave behaviour, and the half-power beam-width is consistent with radiation along the length of the structure.

Figure 3.4 Spectrum of the measured signal radiated by the NL CRLH circuit, showing comparative amplitude f

2 and pump frequencies (approx. 3.2 GHz and 5 GHz respectively) and much weaker f

1

frequencies (around 1.8 GHz).

Figure 3.2 Dispersion characteristic for the NL CRLH TL circuit of Fig 3.1, showing the agreement between measured, simulated and lumped element equivalent circuit modeling. Dotted lines indicate the light lines separating the slow and fast wave regions.

Figure 3.3 Measurement configuration for measurement with helical receive antenna in the foreground and NL CRLH TL with power amplifier mounted on the rotating pedestal. Zero azimuth angle is defined broadside to the plane of the CRLH circuit, with a positive increase to the left.


Figure 3.6 Leaky wave antenna scan angle calculated from the extracted measured (solid) and simulated (dashed) propagation coefficients. Asterisks indicate the approximate beam peaks from Figure 3.5. Dotted curves correspond to scan angle response if propagation direction is reversed above 3.803 GHz.

Figure 3.5 Measured receive power (normalised to the scan peak value) variation with azimuth scan angle, obtained using the measurement setup in Figure 3.3. Parametric f

2 frequencies

are as indicated.


» High-Speed Flows and Microfluidics

SEIT Academics A/Prof Sudhir GaiA/Prof Harald KleineDr Jong-Leng LiowDr Neil MudfordA/Prof Andrew Neely Dr Sean O’ByrneDr Krishna ShankarDr John Young

SEIT Research StaffDr Joseph Kurtz (Research Associate)Dr Mark Aizengendler (Electronics Engineer)Dr Carlos Rodriguez (Research Associate)

SEIT Postgraduate StudentsMr Ashraf AliMr Stefan BrieschenkMr Rishabh ChoudhuryMr Arnab DasguptaMs Priyanka DhopadeMr Zhipeng Gu Mr Varun PrakashMr Deepak Narayan RamanathMr Md. Mahfuzur Rahman ShahMr Vikram SridharMr Zhaolong WangMr Sven WittigMr Guofeng Zhu

Other Collaborators

BAE Systems

Adam Billiards, James Whitford

Colorado State University (USA)

Prof. Ranil Wickramasinghe

The Defence Science and Technology Organisation

Dr Judy Odam, Dr Allan Paull, Dr Nigel Smith

McGill University (Canada)

A/. Prof. Eugene Timofeev

NASA Langley Research Center (USA)

Dr James Moss

Ohio State University (USA)

Prof. Walter Lempert

RWTH Aachen (Germany)

Prof. Herbert Olivier

Tianjin University

Xiubing Jing

United States Naval Academy

David Myre

University of New South Wales

A/Prof. Tracie Barber, Dr Robert Nordon, A/Prof Hans Riesen (PEMS), A/Prof. Gary Rosengarten, A/Prof. John Fletcher, Prof Wang Jun, Dr Li Huaizhong

University of Queensland

Prof. Russell Boyce, Dr Tim McIntyre, Prof. Richard Morgan

University of Southern Queensland

Prof. David Buttsworth

University of Western Australia

Prof. Yee-Kwong Leong

University of the Witwatersrand (South Africa)

Prof. B. Skews

Research DescriptionIn 2011, research continued in the areas of very high-speed flows at supersonic and hypersonic Mach numbers and for very small-scale, low-speed flows for microfluidic applications. The research of high-speed flows has relevance to the development of vehicles for high-speed flight and planetary exploration both in terms of the external aerodynamics and heat transfer associated with atmospheric flight at these speeds as well as the development of propulsion systems such as scramjets to power these vehicles. Quite separately, the investigation of microfluidics is concerned with the scaling of fluid flows to very small geometries and their application to small chemical processing systems often for biomedical needs. The research performed in both areas ranged from fundamental studies to improve our understanding of the underlying physics governing these flows to more application-based studies. These investigations incorporated a wide range of experimental, numerical and analytical techniques.

SCRAMSPACE supersonic combustion flight test (O’Byrne, Neely, Ray, Petersen, Kurtz, Aizengendler, Rodriguez, Krishna, Wittig, Ur Rehman, Dasgupta)This project is part of the Australian Space Research Program SCRAMSPACE project, performed in conjunction with the University of Queensland and t13 other national and international organisations. The aim of the project is to successfully launch a scramjet with an axially symmetric nozzle to achieve supersonic combustion at Mach 8 over a range of altitudes. UNSW Canberra is contributing its expertise in laser diagnostics, thermal paints, optimisation and control theory to the project.

In 2011 we continued the development of a diode-laser-based oxygen sensor to measure the flow speed and temperature in the inlet of a supersonic combustion ramjet engine. The design phase was completed, and construction of a prototype has begun. We have developed miniaturised laser current and temperature controllers that can be used under flight conditions. Our group has developed models of the expected heating of the sensor during flight, and has tested the performance of the diode lasers under these extreme temperature conditions and integrated the optical sensor with the rest of the scramjet payload.


Progress has also been made in development of hypersonic control algorithms and development of constrained optimisation algorithms for development of optimal inlet designs.

Free flying models in hypersonic facilities (Prakash, Mudford, O’Byrne, Neely, Aizengendler)We have continued our research into the development of free-flying instrumented models for the study of hypersonic flows, by performing high-speed visualisations of hypersonic drop test experiments, and developing a new, miniaturised heat flux measurement system which can make simultaneous measurements from four thin-film temperature sensors.

CARS measurements of electric field strength in gases (O’Byrne)During Dr O’Byrne’s sabbatical in 2011, he collaborated with Prof. Walter Lempert at Ohio State University in developing a new version of the coherent anti-Stokes Raman Scattering (CARS) technique for nonintrusively measuring the electric field strength in hydrogen gas. Picosecond-duration pulses of intense laser light were used to achieve the very high time resolution required to make measurements in very short-duration plasma events. This work coincided with a collaborative project involving development and testing of a device for generating pulsed nanosecond-duration plasmas, with the device designed by A/Prof. John Fletcher and Dr Toan Phung from UNSW Kensington. The combination of these technologies will allow us to better understand the behaviours of these very short-duration pulsed plasmas, which have uses that range from flow control to ignition of fuels and sterilisation of biological samples.

Simulation of hypersonic separated flows (Gai, O’Byrne, Neely, Kleine, Ramanath)We have continued our collaboration with Dr James Moss of NASA Langley Research Center, on the simulation of low-density hypersonic separated flows using the Direct Simulation Monte Carlo method. This work builds upon our previous successful work on the separated wake flows of re-entry vehicles by investigating thermal nonequilibrium effects on these flows. This work shows how the translational, rotational and vibrational temperatures of a molecule at these conditions can differ from each other by several orders of magnitude, and the assumption of equilibrium internal energy in the molecules within those flows, although common, is a poor description of their thermal behaviour. Capturing this behaviour can have significant effects on predictions of heating for probes entering the atmospheres of other planets.

We have also found that the size of the separated region is strongly dependent on the wall temperature of these vehicles.

A separate study investigated hypersonic, high-enthalpy flow over a rearward-facing step using computational fluid dynamics (CFD). Two conditions relevant to suborbital and superorbital flow with total specific enthalpies of 26 and 50 MJ/kg, were considered. The Mach number and unit Reynolds number per metre were 7.6, 11.0 and 1.82 X E+06, 6.23 X E+05 respectively. The Reynolds number based on the step height was correspondingly 3.64 X E+03 and 12.5 X E+02. The computations were carried out assuming the flow to be laminar throughout and the real gas effects such as thermal and chemical non-equilibrium are studied using Park’s two-temperature model with finite-rate chemistry and Gupta’s finite-rate chemistry models. In the close vicinity of the step, detailed quantification of flow features was emphasised.

Instrumented free-flight model

Scramspace sensor source optical unit

Thermal model of optical unit heating during flight


In particular, the presence of the Goldstein singularity at the lip and separation on the face of the step was elucidated. Within the separated region and downstream of reattachment, the influence of real gas effects was identified and shown to be negligible. The numerical results were compared with the available experimental data of surface heat flux downstream of the step and reasonable agreement was shown up to 30 step heights downstream.

Fluid-Structure Interaction of Gas Turbine Blades (Dhopade, Neely, Young, Shankar)This study has investigated the effects of low-cycle and high-cycle fatigue interaction on the aerodynamic and structural behaviour of a fan blade. A numerically based analysis through the interfacing of computational fluid dynamics (CFD) and finite element modelling (FEM) analysis, referred to as fluid- structure interaction (FSI) was performed in order to estimate the fatigue life of the blade. A numerical study using one-way FSI simulations to predict representative fluctuating loads on the fan rotor blades of the first axial compressor stage of a representative gas turbine engine was performed. The stator blade was modelled upstream of the rotor blades to simulate the turbulent shedding of wakes that result in aerodynamically induced vibrations of the rotor blades, a leading cause of high-cycle fatigue. The rotor blades are also subject to low-cycle fatigue induced by both the high rotational loads and the mean aerodynamic pressure loading experienced by the blades at various operating conditions. The transient results reflected the oscillatory nature of the pressure loads and resulting stresses on the blades. A stress-life analysis used to estimate the fatigue life of the blade based on the stresses from the FSI analysis demonstrated that it has the potential to be a useful tool in determining the effect of an HCF and LCF interaction on the fatigue life of rotating components.

Streamlines and normalised pressure contours behind a rearward facing step at two hypersonic enthalpies (26 MJ/kg and 50 MJ/kg)

Static pressure distribution on first stage fan stator and rotor bladeslife of rotating components.

Translational temperature maps of a hypersonic separated flow with wall temperatures of (above) 300 K and (below) 1000 K


Supersonic flows over shallow cavities (Sridhar, Gai, Kleine)The study of compressible cavity flow has been an important topic in the field of aerodynamics and acoustics. Cavity flows are encountered in essentially all moving vehicles, from automobiles to aircraft to missiles. These cavities are present in the aircraft in the form of weapon bays, landing doors etc. Although the geometry of these cavities is simple, their unsteady fluid dynamic behaviour is complicated and difficult to predict both in subsonic and supersonic flows. These fluid phenomena typically cause unwanted drag, structural noise and vibrations.

The results show that the flow undergoes a significant structural change when L/D is increased beyond about 5. Cavities with L/D < 5 show a highly unsteady oscillatory structure while those with L/D > 5 exhibit a steady oscillatory flow within the cavity. This has important implications with regard to noise and vibrations of a structure that incorporates cavities in its design.

Shock reflection off cylindrical surfaces (Kleine)In spite of considerable research effort in past decades, the reflection of shock waves off convex cylindrical surfaces still poses a number of unanswered questions. For a given shock Mach number M

S, the reflection pattern changes from

regular to irregular at a certain wall angle θW. If one

determines this transition angle by visual inspection of the reflection pattern and defines it as the location of the first occurrence of a visible Mach stem, one typically arrives at wall angle values lower than the one found in the pseudo-steady case for a straight wedge at the same Mach number. This would indicate that the regular reflection pattern is maintained longer on the cylindrical surface compared to the straight wedge case. Numerical simulations, on the other hand, suggest that the transition occurs at the same wall angle as for the straight wedge. If this were the case, the transition would be governed by the local wall angle and would not be influenced by the preceding history of the reflection.

Two streamline plots for the case of L/D = 3: the flow field is characterised by the presence of a number of unsteady vortices.

Time-resolved shadowgraph visualisations showing three instants of the interaction of a shock wave with three cylinder models of two different radii.


An extensive study of this configuration was undertaken in order to clarify whether the radius of the cylinder and the initial angle (in the case of partial cylindrical models) influence the transition point. Experiments reported in the literature appear to confirm such an influence. Both aspects are directly linked to the aforementioned quest for a transition criterion for shock reflection off curved surfaces.

The analysis of the obtained records yields the following conclusions:

1. the radius of the cylinder influences the shock pattern, but this influence appears to be minute unless one compares cylinders that differ in size by more than an order of magnitude.

2. tests with the partial models have clearly shown that the transition process has started before the Mach stem becomes visible; the transition delay reported in the literature may therefore simply be caused by the difficulties to detect a minute Mach stem.

3. The influence of the Reynolds number on the process is only visible if this number changes by more than one order of magnitude,

Simulation and measurement of fluid-thermal-structural behaviour of hypersonic vehicles (Choudhury, Dasgupta, Neely)To quantify the structural behaviour of hypersonic vehicles work has continued on developing and applying techniques to simulate and measure the fluid-thermal-structural interactions that result from high-speed flight. The prototype of an electric arc-based heating rig was developed and demonstrated that can reproduce the temperature histories experienced by structural components in the highly transient flight tests performed from the Woomera range. This calibration facility uses a large welding power supply to heat painted samples via electric arc. Computer control of the rig has now been implemented allowing the prescription of a pre-designated power history. This results in a corresponding surface temperature history on the sample. This rig has been successfully operated in open loop mode and will be used to calibrate the thermal paints used in the flight experiments. Work is ongoing to correlate the power input and temperature result for open-loop operation and to eventually implement closed-loop control of the calibration rig. This will enable calibration of the paint response both pre flight for the nominal predicted trajectory and post flight for the actual trajectory flown. 3-D simulations of the atmospheric heating experienced by the HIFiRE-0 vehicle during its flight in 2009 were performed to provide the heating histories for the paint calibrations and these are ongoing. In collaboration with DSTO, the HIFiRE-5 hypersonic test flight vehicle was instrumented with extensive patches of permanent-change thermal paint with expected launch sometime in the second half of 2012. This work was performed as part of a collaboration with A/Prof Riesen from PEMS, UNSW Canberra and Dr Paull and Dr Odam from DSTO.

Fluidic Thrust Control (Rodriguez, Ali, Neely, Young)Methods of vectoring and modulating exhaust thrust in a converging-diverging nozzle by secondary fluidic injection were investigated. The application of fluidic thrust control (FTC) offers potentially significant gains in performance and manoeuvrability without the cost of heavy mechanical systems. FTC nozzles also have significant advantages in relation to reducing observability and are particularly suited to low- cost, lightweight, highly maneuverable missiles and unmanned combat air vehicles. Two methods of the FTC, Shock Thrust Control (STC) and Throat Shifting (TS), were investigated in both 2D and 3D configurations using numerical simulations. In the STC method, shocks are induced in the supersonic flow by the injection of a secondary flow from the walls of the diverging section of the nozzle. This study considered the use of symmetric injection from the walls of the diverging nozzle to generate strong normal shock waves in the flow to modulate the exhaust thrust. In the TS method secondary flow is injected from the walls of the nozzle throat to modify its apparent shape. While the initial STC simulations demonstrated the ability to modulate thrust, the configuration used was not able to reduce it.

!

!

Contour plots of flow field Mach number and structural temperature during the descent of a hypersonic nose cone.


For the STC method the result indicated that pressure thrust was the dominant term when modulating the thrust. Total thrust, which is the sum of momentum thrust and pressure thrust, increased as the reduction in momentum thrust was much less than the increase in pressure thrust. For the TS case, the effect of slot size to throat size and the interaction of the parameters with nozzle operating pressure and injection angle had significant effects on the performance of the nozzle. Increased secondary to primary mass flow ratio increased the modulation of thrust in the TS method. This project is a collaboration with BAE Systems and the Department of Defence.

Modelling of flow in a micro-hydrocyclone (Zhu, Liow, Neely)Micro-hydrocyclones are miniature-scale hydrocyclones with applications in micro-devices. As hydrocyclones do not have any moving parts, they are easier to control in micro-devices and have the potential to be more reliable. The flow in a 5 mm diameter micro-hydrocyclone was modelled in FLUENT to investigate the fluid flow and particle separation ability. Direct numerical simulation (DNS) results have shown that the flow transition and subsequent unsteady state behaviour occurred in the micro-hydrocyclone at a low Reynolds number (Rein=300) because of the onset of centrifugal instability. The centrifugal instability results in flow transition from laminar to the development of turbulent flow in the hydrocyclone. This flow transition has not been studied in previous modelling work of hydrocyclones as they normally operate in the highly turbulent region in industry. The centrifugal instability in the micro-hydrocyclone begins as Görtler vortices developing in the boundary layer which subsequently affect the flow field. Particle motion tracing showed that improved separation with finer cut size, d

50, and

steeper separation sharpness were obtained as the inlet velocity was increased. This improvement is enhanced by the change in the flow characteristics when the flow transits to turbulent flow.

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!"#

!

!"!#$!%&'()$"%*+*,-$!%&./)$#'0.1(2',$

!

Thrust = ˙ m Vexit + Aexit (Pexit " Pambient )

12' 3).45,+'

Contour plots of Mach number and injectant mixing for thrust modulation via throat injection (TSTM) in 2D and conical nozzles.

a b c1 c2

Contours of vorticity in a vertical plane (0 and 180° azimuthal positions) of the micro-hydrocyclone for (A) 0.1, (B) 0.2 and (C) 0.4 m/s inlet velocities (A, B & C1 - one time-step results after the flow reached a statistically steady state and C2 - time-averaged results). The increased vorticity at the wall with higher inlet velocities are a consequence of the formation of Görtler vortices.


Experimental study of cutting forces in micro end-milling (Jing, Li, Wang, Liow)Micro-end-milling is an efficient and economical manufacturing operation that is capable of accurately producing high aspect ratio features and parts. This is used in the production of microfluidic components for study of fluid flow in micro-devices. The cutting forces affect the quality of the surface which in turn affects the fluid flow characteristics at the wall boundaries of the micro-channels. Studies were carried on the cutting forces and surface roughness by micro-end milling of 6160 aluminum alloy. The cutting forces were found to increase with increasing feed rate for end-mills having diameters of 600 and 900 micrometres.

An indicator called as percentage peak force difference was introduces to investigate the effect of tooth runout on the cutting force variation. It has been found that the effect of tooth runout on the peak force variation increases when the feed per tooth decreases, and that it increases when the cutting speed increases with the same feed per tooth. The results provide a means of controlling the machining of micro-channels enabling particular fluid flow behaviour to be manifested in a given micro-channel design.

Investigation on the droplet formation time with xanthan gum solutions at a t-junction (Gu and Liow)Xanthan gum solutions with various concentrations were used as the dispersed phase to study the formation time for drop formation at a T-junction. Two critical concentrations (0.05 and 0.2 wt%) of xanthan gum solutions were observed resulting in three distinct regimes. The droplet diameter increased with increasing xanthan gum concentration within each regime but the transition through each critical concentration was accompanied by a significant reduction in the droplet size. Experimental results showed that the droplet formation time decreased exponentially with increasing continuous phase flow rate. It was also found that the formation time was reduced with increasing dispersed phase flow rate. Xanthan gum solutions with a higher concentration within each regime resulted in a longer formation time, and there was a decrease in the formation time at each critical concentration.

The formation time consists of growth and breakup stages and the effect of xanthan gum concentration on each stage was examined. The results showed that it is possible to control the drop sizes of the dispersed phase flow for different xanthan gum solution concentrations by varying the flow rates.

Force measured for a 600 μm diameter end mill cutter running at 3μm/tooth with different cutting speeds


The variation of droplet formation behaviour and time for 0.01%, 0.025% and 0.1% xanthan gum solution (∆t=10 ms).


0.01% xanthan gum 0.025% xanthan gum 0.1% xanthan gum

Growth stage

0 0 0

6∆t 4∆t 6∆t

12∆t 9∆t 13∆t

18∆t 15∆t 19∆t

End of growth 24.2∆t 18.6∆t 25.3∆t

Breakup stage

30.2∆t 27.6∆t 32.3∆t

37.2∆t 38.6∆t 39.3∆t

43.2∆t 47.6∆t 46.3∆t

50∆t 54.3∆t 53∆t

The variation of droplet formation behaviour and time for 0.01%, 0.025% and 0.1% xanthan gum solution (∆t=10 ms).


» Image CodingSEIT AcademicsProf John ArnoldProf Michael FraterA/Prof Mark PickeringDr Matt GarrattDr Andrew Lambert

SEIT Postgraduate StudentsQiang Li Md Nazmul Haque Md Hafizur Rahman Md Asikuzzaman Ashek Ahmmed

SEIT Research StaffDr Moyuresh Biswas

Research DescriptionDigital television is now big business worldwide, and techniques that can lead to improved compression of audiovisual services are of great interest both to international standards bodies and to industry. Indeed, the increasing capacity of communications systems is often outpaced by the increasing demand for access to audio-visual services. The development of more efficient transmission techniques for audiovisual services will be of considerable benefit to all regions of Australia and in particular to remote regions. It can be expected that the development of this technology will significantly improve service quality in these areas without the need for upgrading the existing telecommunications infrastructure. This will allow, for example, pay and free-to-air operators to provide additional services within their current bandwidth limitations. Staff and students in the Image Coding Lab are currently working on a number of projects relating to the compression and analysis of images and video sequences.

Dense Depth Estimation Using Adaptive Structured Light and the Cooperative Algorithm

In this project we proposed a new depth estimation approach using adaptive structured light. In the proposed approach, a random noise adaptive structured light pattern is projected onto objects and then two cameras capture stereo images. The adaptive colors for the random noise pattern are acquired using principle component analysis in the RGB color space of the image of the scene. By using inverse principle component analysis on the images with structured light, it is possible to maximize the energy of the structured light and meanwhile minimize the energy of other noise factors.

By combining the original three RGB channels of the scene under adaptive structured light with a fourth channel generated using inverse principle component analysis we can use the cooperative global optimization algorithm to generate a dense depth map. In order to keep clear depth discontinuities and alleviate noise in the depth map, we aggregate the local match score with shiftable windows. Experimental results show our approach performs well on images of real-world objects with strong colours and complex textures that have been captured under ambient light conditions. Figure 1 shows images of an example scene taken under ambient and structured light, the image extracted using principle component analysis and the depth map generated by the proposed approach.

Figure 1: (a) scene under ambient light and adaptive structured light, (b) the extracted third component, (c) the depth map generated by the proposed approach.


Fast Image Registration Using a Multi-Pass Image Interpolation ApproachImage registration is a fundamental technique in image processing. It is used to spatially align two or more images that have been captured at different times, from different sensors, or from different viewpoints. There have been many algorithms proposed for this task. The most common of these being the well-known Lucas-Kanade and Horn-Schunk approaches. However the main limitation of these approaches is the computational complexity required to implement the large number of iterations necessary for successful alignment of the images. In this project we developed an alternative approach for image registration using a modified version of the Image Interpolation Algorithm (I2A). Our proposed approach requires far fewer iterations to successfully register two images than the standard Lucas-Kanade approach. This means that our approach is much more suitable for pipelined hardware implementations that are required in real-time FPGA-based registration applications. Figure 2 shows the percentage of successful registrations produced by our proposed approach and the standard Lucas-Kanade registration algorithm after a certain number of iterations. It can be seen from these two curves that for the same number of iterations the success rate of the MP-I2A approach is much better than for the Lucas-Kanade algorithm. For example the success rate for the MP-I2A algorithm is 95% after four iterations while the rate for the Lucas-Kanade algorithm is less than 20%.

An Adaptive Low-Complexity Global Motion Estimation Algorithm The computational complexity of motion estimation between video frames for video coding remains a significant challenge even with current computing power. An important recent advance in the development of efficient motion estimation algorithms is the use of image registration in the estimation of global motion parameters for object-based video coding. However, the main disadvantage of this approach is the increased computational complexity required to estimate the parameters which define the more complex motion models. In this project we developed a new low-complexity algorithm for global motion estimation. The complexity of the algorithm was reduced by performing the majority of the operations in the gradient-descent optimization using logic operations rather than full-precision arithmetic operations. The new hierarchical-adaptive low complexity (ALC-H) approach was compared with the following algorithms: the 8-bit GN algorithm, ALC, ALC-H(1-bit), ICA, ICA with adaptive step-size choice (ICA-SSC), BPS7, Dufaux and Konrad’s coarse-to-fine algorithm and Alzoubi & Pan’s approach of using a small portion of the available data. To evaluate the performance of the proposed algorithm, frames from standard video test sequences were transformed using an affine transform with randomly chosen values for the 6 motion parameters. The algorithms under investigation were then used to register the transformed images to the original image. We took frames from each sequence and applied 100 transformations (randomly generated with the above-mentioned parameters) to generate 100 different transformed images. Although the transformations were chosen randomly, they were the same for all algorithms. The average PSNR at each iteration for all successful cases is shown in Figure 1 for the algorithms under investigation. It can be seen from Figure 1 that, except for the algorithm of Alzoubi and Pan, all of the fast algorithms converge to an average PSNR which is equal to that of the full precision GN algorithm. Of the algorithms tested, our new ALC-H algorithm is the fastest to converge and requires only 40-50 iterations on average for successful registration.

Figure 2: The registration success rate of the MP-I2A and Lucas-Kanade algorithms.

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Scale and Rotation Invariant Gabor Features for Texture RetrievalFor image classification applications it is often useful to generate a compact representation of the texture of an image region. The conventional representation of image textures using extracted Gabor wavelet coefficients often yields poor performance when classifying scaled and rotated versions of image regions. In this project we developd a scale and rotation invariant feature generation procedure for classification of images using Gabor filter banks. Firstly, to obtain scale and rotation invariant features, each image is decomposed at different scales and orientations. Then, in order to create unique feature vectors, we apply a circular shift operation to both scale and rotation dimensions to shift the maximum value of the Gabor filters to the first orientation of the first scale and the energies of these filtered images are calculated. To demonstrate the effectiveness of our proposed approach we compared its performance with the most recent texture feature generation methods in a classification task. Experimental results showed that our proposed feature generation method is more accurate at classifying scaled and rotated textures than the existing methods.


» Imaging Through Turbulence

SEIT AcademicsDr Andrew Lambert Dr Murat Tahtali A/Prof Harald KleineA/Prof Donald Fraser (retd)

SEIT Postgraduate StudentsMr David BowmanSqnldr Malcolm GouldMs Ying LiuMs Si LiuMr Shan Xiu (NUI Galway)Mr Qichao Zhao

Other Collaborators

School of Optometry, QUT

Prof David Atchison

DSTO Australia

Dr Leszek SwierkowskiDr Geoff NichollsDr Garry Newsam

CSIRO

Dr John LasalleDr David LovellDr Charles JenkinsDr Michael Goodwin

Applied Optics, National University of Ireland Galway, Ireland

Prof Chris DaintyDr Nicholas DelaneyDr Liz DalyDr Ruth MackayDr Alex Goncharov

University of Canterbury, New Zealand

Dr Steve Weddell

Research DescriptionIn several different fields, images are distorted by the intervening medium. For example, images of objects observed by telescope often exhibit unwanted distortion and blurring due to distortion of the wavefront by atmospheric turbulence. We are continuing to investigate the restoration of such images, requiring a time-sequence to be captured and processed to remove the distortions and reveal a clear image of the scene.

In addition, we are investigating the distribution and behaviour of the intervening turbulent layers, particularly for Space Situational Awareness (SSA). Similar problems exists when imaging the retina of the eye, in optometry or ophthalmology, due to the inherent optical characteristic of the materials of the eye, and also when imaging objects involving a water surface disturbed by waves. Application areas for these techniques include ground-based and aerial telescopic surveillance, investigation of turbulence severity for astronomy sites, adaptive optics in optometry, and visualisation of objects through water.

Optical and real-time image processing techniques are also easily applied to imaging the full wave-field in the above areas, and in microscopy. Massively parallel image processing techniques are being investigated using grid computing, field programmable gate array (FPGA) clusters, and graphical processing units (GPU).

Horizontal Image Restoration close to the Ground Using Distributed Embedded Systems for Real Time ApplicationsOur interest over recent years has been in the surveillance of objects affected by ground-turbulence at a considerable distance on the Earth’s surface. In astronomy, the disturbing turbulence is usually in only a small number of distinct layers in the atmosphere above the telescope, and the turbulent behaviour is considered to behave according to Kolmogorov statistics. The statistical behaviour of turbulence close to the ground has not been studied before in any detail. To this end, David Bowman has been developing lean algorithms suited to FPGA implementation for processing surveillance image sequences acquired by telescope. David is on a DSA scholarship, augmented by project funds from DSTO. This has been undertaken also in collaboration with Dr Geoff Nicholls at DSTO. The idea of using stream based processing coupled with Neural Networks within the FPGA are the subject of collaborations with Dr Steve Weddell from New Zealand, who visited the group in November.


Applied OpticsAndrew Lambert spent 2010 on sabatical hosted by the Applied Optics group at National University of Ireland, Galway. He would like to thank his sponsors at NUIG for this very productive opportunity. This is a vibrant group of internationally recognised researchers undertaking projects in astronomy, optical communications, and image processing. However, most of the effort is in the field of ophthalmology. Andrew participated in an inaugural study of surveillance imaging over long paths over water, to determine the rational for adaptive optics in seaborne communications systems. He continued to investigate the companioning of high speed digital circuits with adaptive optics systems, an area which is being expanded upon by a shared PhD candidate at NUI Galway, Mr Shan Xui, with emphasis on plenoptic imaging for microscopy.

Work in the adaptive optics area continues, particularly in space and terrestrial surveillance, with PhD candidates, Manuel Cegarro and Sqnldr Mal Gould. The objectives are to investigate compact AO systems with novel wavefront sensing and electro-optics. A demonstrator assembly is being designed for the School’s Meade 16” telescope, and the holographic wavefront sensor is being investigated, with these two students.

Adaptive Optics in Human VisionAndrew Lambert is continuing his collaboration with colleagues at the School of Optometry, QUT, employing adaptive optics for understanding the optical limitations to human vision, improving clinical assessment of the inner eye, and for developing new ophthalmic correcting devices such as accommodating intraocular lenses in the future. ARC funding for this study began this year for a project entitled “Removing the blinkers: a wider study of the human eye. Peripheral aberrations, wide-field retinal imaging and optical parameters“. Tomographic examination of the optics in the human eye may be undertaken while the subject is involved in visual tasks.

A simple version of this process, called SLODAR, involved creation of two angularly separated retinal “sources” which are refracted by the various optical

surfaces and the lens gradient index, and register correlated phase distortion on a wavefront sensor external to the eye. The retinal “sources” (analogous to stars in astronomy) are created from a probe beam pattern imaged into the eye. The shape, position, and surface or volume structure (and hence aberration) for each of the refracting components can then be obtained. New PhD candidate, Ms Si Liu, is focusing her study on this area that may shed insight into the workings of the optics in the human eye.

Work in this area has been largely in improving the beacon creation process, whereby active optics is used to provide a more useful distribution of power at the retina. A Spatial Light Modulator is used in the illumination path to create the likes of a Bessel beam which is less affected by the aberrations experienced by the light en-route to the retina. There are numerous opportunities with this process that have not been before examined.

“Lucky Region” Imaging and Imaging through or over WaterDr (Ms) Zhiying Wen introduced the use of the bispectrum to turbulence image restoration for surveillance and imaging through or into water, in her PhD studies, graduating in 2010. Her own new “lucky region” technique finds the least distorted regions from a time sequence of raw images, and then post-processes the extracted lucky regions using bispectral analysis to obtain a best estimate of the target. The bispectrum has been successfully used in astronomical image restoration for several years, based on the premise that, averaging the bispectrum over a time sequence cancels out the random phase distortions by the intervening medium. Ms Ying Liu continues these studies now as a Masters Candidate.

Figure 1: Beacon creation using a SLM. (left) The phase profile may be encoding on the illumination beam to (right) create an annulus on the retina of the eye to guide adaptive optic correction while imaging the retina, or for investigation of the workings of its crystalline lens.


GPU based intensive algorithm computationMurat Tahtali considers running a Kalman filter per pixel, extracting image field motion from surrounding regions of interest, in real time megapixel imagery, a very real possibility for image restoration for the effects of turbulence in the optical path. He is addressing the real-time computation issues using large clusters of GPU engines.

Applications of the plenoptic camera to turbulence degraded imageryThe GPU engines allow Murat to analyse the recordings of a plenoptic camera which digitise the 3D wavefield. These recordings capture the delays and scattering effects of the turbulence field in the path, utilising a densely packed microlens array and high density image sensor, and we are seeking to evolve this technology to model the turbulence. Murat and Andrew have developed a plenoptic camera with 39 megapixels for examination of the volume effects of turbulence within a shock-tunnel to support the hypersonics work of Harald Kleine.

Space Situational AwarenessTracking space-borne objects, and passively observing their photometric signatures when illuminated only by natural light, is difficult enough, without considering the effects of the intervening atmosphere. We are exploring the concept of a “deploy-anywhere” optical telescope solution for this purpose using the School’s 16” telescope. Problems associated with the prediction of turbulence outside the isoplanatic angle are investigated, as is an inbuilt immunity to sky background and cloud absorption. We are seeking to address these problems with multi-spectral imagery and adaptive optics.

Figure 2: Plenoptic Camera. Images from a trial plenoptic camera formed with a microlens array and consumer 14 megapixel camera capture the direction of illumination as well as the spatial distribution of the image. From these images any depth of focus can be reconstructed with post-processing. Such recordings enable examination of the layers of a turbulent volume within a shock-tunnel.


» Immiscible Contaminants in Natural Porous Media

SEIT AcademicsDr Robert Niven

SEIT Undergraduate StudentsMr Steven Waldrip

SEIT Postgraduate StudentsMs Yasmine Abdelraouf

Other Collaborators

The University of New South Wales

Prof. Nasser KhaliliDr Markus Oeser

The Australian National University

Prof. Mark A. KnackstedtA/Prof. Timothy J. SendenDr Michael L. TurnerDr Adrian P. SheppardDr Jill Middleton

Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany

Dr Kamaljit Singh (former PhD student)

Research DescriptionControl of the geometric form and mobility of an immiscible fluid phase, such as air or hydrocarbon liquids, in water-saturated natural porous media (soil and rock materials) has emerged as one of the most demanding engineering challenges of the 21st century. When subject to fluid flow, such immiscible fluids tend to fragment to form discrete gas bubbles or fluid droplets – commonly referred to as ganglia – which remain trapped in the porous medium due to the strong forces induced by surface or interfacial tension. Such droplets are then effectively immobilised. It has been estimated that some 20-30% of known petroleum reservoirs have been rendered unrecoverable by this mechanism, of critical importance in light of concerns over limitations to world oil supply (“peak oil”). In addition, such entrapment substantially increases the cost and difficulty of remediation of immiscible contaminants, such as hydrocarbons and solvents, from contaminated sites. Furthermore, efforts to redress global warming by the geosequestration of CO

2, involving the injection of CO

2 into deep geological

formations, could be significantly impaired by this mechanism. For these reasons, a long-standing body of research has been conducted in SEIT on the behaviour of immiscible fluids in natural porous media.

In 2011 the following projects were conducted as part of this research theme:

CO2 Sequestration in Deformable, Chemically Interactive Porous MediaA major project was continued on the effect of CO2 sequestration in deformable, chemically interactive, double porosity media, following the award of a Australian Research Council Discovery Grant for 2010-12 (DP1096480, investigators Khalili, Niven and Oeser). This project examines the effect of injection of supercritical CO2 into deep geological formations, both experimentally and computationally, in the latter involving a composite multiphase / multiporosity flow, deformation and heat transport code. Of particular interest is the possibility of deformation (and, potentially, failure) of the rock matrix due to CO2 injection, which would render the CO2 storage inoperable. A PhD student was recruited in SEIT to couple the flow and deformation codes to a chemical thermodynamics model, to account for chemical reactions between the supercritical CO2 and ambient geochemical materials. Theoretical and modelling analyses are now underway, and one analysis is currently being summarised for publication.

Effect of Freeze-Thaw on Oil-Contaminated SoilsIt is well known that freeze-thaw cycles, due to seasonal and/or daily fluctuations in temperature about 0oC, can dramatically alter the fabric, stratigraphy, moisture distribution and many other properties of natural soils. However, despite its significance to the oil-fields of Alaska, Siberia and Canada, only a handful of studies have examined the effect of freeze-thaw processes on the entrapment of immiscible fluids (hydrocarbons or solvents). Research within SEIT by Dr Niven and Dr Kamaljit Singh (2009 PhD graduate), in collaboration with researchers at the X-ray tomography facility at ANU, has revealed that freeze-thaw cycles induce substantial fragmentation of entrapped hydrocarbon ganglia and their remobilisation in the direction of freezing. A rendered image of the X-ray tomographic results is shown in Figure 1. Following publication of (what we believe to be) the first manuscript on this topic 2008, a further manuscript was published in 2011 (Singh et al., 2011), with one further article in press (Singh et al., in press).


Shape of Immiscible Fluid Droplets Entrapped in Porous MediaFundamental research was also undertaken on the shape of an immiscible fluid ganglion (such as oil) in contact with solid spheres in the presence of a continuous fluid (such as water), as governed by the Young-Laplace equation, a highly non-linear partial differential equation. The shape has important ramifications for the force of entrapment of the droplet, and hence the mobility of oil in petroleum reservoirs and contaminated soils. The project was led by Mr Steven Waldrip, a former BE (Civil Engineering) student at UNSW Canberra, who was recruited as a research fellow. A finite element code was implemented to solve this equation for the shape of the fluid droplet, involving mapping between spherical and Cartesian coordinates, subject to a free boundary condition. A manuscript is currently under preparation to summarise the results of this work.

Figure 1: Rendered X-ray tomogram of hydrocarbon ganglia (yellow) and water (blue) in bead pack (clear), at residual saturation.


» Operations Research and Optimisation

SEIT AcademicsA/Prof Ruhul Sarker Prof. Hussein AbbassDr Daryl EssamDr Chris LokanDr Michael MaherDr Alan McLucas Prof Charles NewtonDr Tapabrata Ray

SEIT Postgraduate StudentsMr Md. AsafuddoulaMr Saber Mohammed Elsayed Mr Abdelmonem fouadMrs Noha Mohamed HamzaMs Eman Samir HasanMrs Hawa HishamuddinMs Farhana NazninMd. Humyun Fuad RahmanMr Nurhadi Siswanto

SEIT Research StaffMr Fan Qi

Other Collaborators

School of Business, UNSW Canberra

Dr Jason Mazanov


A/Prof Tuan Pham, Dr Sami Kara, A/Prof Bermian Kayis


Dr David Cornforth

Curtin University of Technology

Prof M Quaddus

Queensland University of Technology

Prof Erhan Kozan

Monash University

Dr Joarder Kamruzzaman

Victoria University

A/Prof Rezaul Begg, Dr Lutfar Khan

University of Lethbridge, Canada

Prof. Sajjad Zahir

National Defence Academy, Japan

Prof Akira Namatame

Anna University, India

Prof K S P Rao

Pennsylvania State University, USA

Dr Aman Haque

Research DescriptionOptimisation problems arise in many real-life design, planning and decision processes. Most real-world optimisation problems are complex as they involve interacting variables and parameters, restrictions, ambiguous goals and one or more objectives. Typical examples of such problems are: planning, resource allocation, logistics, inventory control, scheduling, and company operations problems. Worldwide, organizations are facing the problem of appropriately modelling and solving their complex decision problems. The optimal solutions of such problems would result in higher productivity in those organisations.

The Operations Research (OR) and Optimisation group, at UNSW Canberra, conducts both theoretical and applied research for solving complex optimisation problems. The group covers a wide range of topics including modelling and solving real-world problems, analysing and improving existing OR techniques, developing new heuristic algorithms, applying Artificial Intelligence techniques to OR, and developing new intelligent systems based techniques for optimisation problems. The group also works on soft OR techniques and their implementation for solving real-world complex decision problems.

The Operations Research and Optimisation group receives financial support from the Australian Research Council, the Defence Science and Technology Organisation and the University of New South Wales.

Production Scheduling under DisruptionThe job scheduling problem (JSP) is considered as one of the most complex combinatorial optimization problems. JSP is not an independent task, but rather a part of a company business case. In this research, we (Hasan, Sarker and Essam) have first solved JSPs using an Improved Memetic Algorithm (IMA). We have studied JSPs under sudden machine breakdown scenarios which introduces a risk of not completing the jobs on time. We have extended IMA to deal with the changed situation, and developed a simulation model to analyze the risk using a job order-and-delivery scenario. So the paper has made three sequential contributions: job scheduling under ideal condition, rescheduling under machine breakdown, and risk analysis for a production business case. The extended algorithm provides better understanding and results than the existing algorithms, the rescheduling shows a good way of recovering disruptions, and the risk analysis shows an effective way of maximizing return under such situations. A part of this research has been reported in a paper published in the International Journal of Production Research in 2011.


DMEA: a direction-based multiobjective evolutionary algorithmA novel direction-based multi-objective evolutionary algorithm (DMEA)is proposed, in which a population evolves over time along some directions of improvement. We [Bui, Liu, Bender, Barlow, Wesolkowski and Abbass] distinguish two types of directions: (1) the convergence direction between a non-dominated solution (stored in an archive) and a dominated solution from the current population; and, (2) the spread direction between two non-dominated solutions in the archive. At each generation, these directions are used to perturb the current parental population from which offspring are produced. The combined population of offspring and archived solutions forms the basis for the creation of both the next-generation archive and parental pools. The rule governing the formation of the next-generation parental pool is as follows: the first half is populated by non-dominated solutions whose spread is aided by a niching criterion applied in the decision space. The second half is filled with both non-dominated and dominated solutions from the sorted remainder of the combined population. The selection of nondominated solutions for the next-generation archive is also assisted by a mechanism, in which neighborhoods of rays in objective space serve as niches. These rays originate from the current estimate of the Pareto optimal front’s (POF’s) ideal point and emit randomly into the hyperquadrant that contains the current POF estimate. Experiments on well-known benchmark sets have been carried out to investigate the performance and the behavior of the DMEA. We validated its performance by comparing it with four well-known existing algorithms. With respect to convergence and spread performance, DMEA is very competitive.

Real-time Routing and Tracking Algorithms Real-time routing and tracking require different optimization algorithms from their offline counterparts. Another name to real-time is time-constrained problems, where a solution is needed within a constrained – and normally shorter – timeframe. Here, traditional offline optimization algorithms that rely on heavy computations and long time to reach an optimal solution fail to deliver high quality solutions in a time-constrained environment. Moreover, when faced with a real-time problem, it is common that the full problem is not known in advance. For example, parameter values may not be available in advance, they may change during the course of solving the problem, and some variables may become more relevant or even redundant. This imposes a challenge that is not normally the focus of traditional offline optimization algorithms. This project focuses on developing novel optimization algorithms for this class of problems.

An Optimization Framework for the Design of Underwater VehiclesRecently, the Multidisciplinary Design Optimization group at UNSW j95 Canberra has developed an optimization framework for the preliminary design of underwater vehicles [Ray, Anavatti, Chris, and Alam]. The framework allows the designer to identify optimum underwater vehicle designs based on a set of user and mission requirements. The framework is realized by coupling commercial tools (CATIA-ICEM-FLUENT) with in-house state of the art optimization algorithms. Two such designs are presented below which have been built.

Figure 1: A sample output for breakdowns of a job scheduling problem

Figure 2(a): Optimum Design of the Underwater Vehicle


Handling Equality Constraints in Evolutionary OptimisationOver the last few decades several methods have been proposed for handling functional constraints while solving optimization problems using Evolutionary Algorithms (EAs). However, the presence of equality constraints makes the feasible space very small compared to the entire search space. As a consequence, the handling of equality constraints has long been a difficult issue for evolutionary optimization methods. In this research, we (Barkat Ullah, Sarker and lokan) present a Hybrid Evolutionary Algorithm (HEA) for solving optimization problems with both equality and inequality constraints. In HEA, we propose a new local search technique with special emphasis on equality constraints. The basic concept of the new technique is to reach a point on the equality constraint from the current position of an individual solution, and then explore on the constraint landscape. We believe this new concept will influence the future research direction for constrained optimization using population based algorithms. The proposed algorithm is tested on a set of standard benchmark problems. The results show that the proposed technique works very well on those benchmark problems. A paper based on this research has recently been accepted in the European Journal of Operational Research (ERA A).

Multi Objective Learning Classifier Systems Based Hyperheuristics for Modularised Fleet Mix ProblemThe Modularised Fleet Mix Problem (MFMP) is a defence industry variant of the generalised Fleet Size and Mix (FSM) problem. It is used as a modelling and planning tool for estimating future military fleets that are capable of fulfilling a range of anticipated missions in the future in a cost effective and efficient manner. Heuristic-based optimisation techniques are used to obtain approximate solutions to MFMP.

In this project we (Shafi, Bender and Abbass) present an offline hyperheuristic for MFMP using two Michigan style Learning Classifier Systems (LCS). Hyper-heuristics in optimisation refer to search techniques that operate on a primitive heuristics space instead of a solution space. The LCS based multi-objective hyperheuristic is built from multi-objective low-level heuristics derived from an existing heuristic based solver for MFMP. While the low-level heuristics use multi-objective evolutionary algorithms to search non-dominated solutions, LCS based hyperheuristics apply the non-dominance concept at the primitive heuristic level. Two LCS, namely eXtended Classifier System (XCS) and sUpervised Classifier System (UCS) are augmented by multi-objective reward and accuracy functions respectively to incorporate this effect. The results show that UCS performs better than XCS in selecting heuristics in test instances which are closer, in terms of a distance-based convergence metric, to the derived global Pareto curves in these instances.

Inventory System with Transportation Disruption Supply chains (SC) are becoming increasingly competitive and complex in order to effectively meet customer demands. This nature and complexity of the SCs make them vulnerable to various risks, including disruptions due to interruptions in supply, transportation and many other sources. In the presence of a disruption, managers are required to make quick and reliable decisions to recover from the unexpected event with as minimal costs as possible. In this study, a recovery model is assessed for a two stage production and inventory system that experiences a transportation disruption. The model is capable of determining the optimal ordering and production quantities during the recovery window such that the total relevant costs are minimized, while seeking to recover the original schedule. Such tools are useful to assist managers in effective decision making in response to disruptions, in particular when determining the optimal recovery strategy for the longevity and sustainability of their businesses. For this research, we (Hisamuddin, Sarker and Essam) received the best paper award from the International Conference on Industrial Engineering and Service Science (IESS) in 2011.

Figure 3: A sample diversity of population with different design of next generation.

Figure 2(b): Optimum Design of the Six-Inch Sub


Ship Inventory Routing and SchedulingThis research investigates a ship inventory routing and scheduling problem with undedicated compartments (sIRPSP-UC). The objective of the problem is to find a minimum cost solution while satisfying a number of technical and physical constraints within a given planning horizon. In this problem, we identify four sub-problems that need to be decided simultaneously: route selections, ship selection, loading, and unloading activity procedures. First, we (Siswanto, Essam and Sarker) develop an equivalent mixed integer linear programming of the problem. Then, we propose a set of heuristics for each sub-problem and find the best combination of heuristics that ensures an overall best solution for the entire problem.

In 2011, we considered a new variant of the maritime inventory routing problem which involved multiple time windows, and is hence called the multiple time windows problem. We have developed a mathematical model for this problem. However, due to the excessive running time required for the mathematical model, we have also developed a multi-heuristics based genetic algorithm. The multi-heuristics are composed of a set of strategies that correspond to the above four decision points. We used this set of strategies in a genetic algorithm framework so as to find the best strategies. The computational results show that the multi-heuristics can get acceptable solutions within a reasonable running time. Moreover, the flexibility to add or remove the strategies means that the proposed method would not be difficult to implement for other variants of the maritime inventory routing problem. From this research, a paper has been published in Computers and Industrial Engineering in 2011.

Shape Representation and Optimization

Shape representation plays a key role in many applications such as image analysis, pattern recognition, computer graphics and computer aided animation [Ray and Khan]. A novel shape evolution scheme has been developed within the group. Two examples of such shape evolution are presented here in the context of wing morphing to aid existing research in flapping wing design.

A Novel Repair Mechanism based on Most Probable Point of FailureHandling equality constraints is a challenging endeavour for researchers in optimization. A single equality constraint can pose serious difficulties to an optimization algorithm severely limiting its capability when the size of the feasible search space is small. This work introduces a novel approach for repairing infeasible solutions, wherein one or all the solutions of the population are repaired to yield feasible solution(s). Subsequently, a suitable classic or evolutionary optimization procedure can be used to obtain optimal solution(s). Our [Ray and Saha] current approach is implemented within a Real-coded Genetic Algorithm (RGA) framework and the repair method is based on the idea of Most Probable Point (MPP) (of failure) which is derived from the context of Reliability Based Optimization (RBO). Promising results have been obtained for problems with equality constraints and ones with active inequalities.

Figure 4: Evolution of generated dragonfly-wing (thin) towards the target dragonfly-wing (thick) for matching.

Figure 5: Evolution of generated damselfly-wing (thin) towards the target damselfly-wing (thick) for matching.


Learning from Evolutionary Algorithm based Design Optimization of Axisymmetric Scramjet InletsOptimisation is a key element in today’s design processes and there is an ever increasing emphasis on development of efficient algorithms to deal with computationally expensive optimisation problems. While surrogate assisted optimisation methods are commonly used for such problems, there are few studies that attempt to understand the optimal solutions. A study was undertaken to uncover hidden relationships among the variables in the promising regions of the search space. Such relationships can be subsequently used to separate promising and unpromising designs [Ray, Saha, Boyce, and Ogawa]. An illustration of its classification ability for a 3 objective scramjet inlet design problem is illustrated below (Red: unpromising designs, Blue: promising designs).

An Evolutionary Multi-objective Scenario-Based Approach for Stochastic Resource Investment Project SchedulingMany planning problems, such as mission capability planning, can be modelled as project scheduling problems. Unlike conventional deterministic project scheduling problems, such problems involve uncertainty and the execution of the plan will definitely be perturbed by many factors. In other words, the circumstances under which the plan will be executed are changing and stochastic. In this paper, we [Xiong, Liu, Chen, and Abbass] first use scenarios to represent the stochastic elements in the problem; these are: perturbation strength and perturbation occurrence time. We define and explain the Stochastic Resource Investment Project Scheduling (SRIPS) problem. A multi-objective optimization model of SRIPS is proposed where three optimization objectives are considered simultaneously: makespan, cost, and robustness. A multi-objective genetic algorithm is employed to solve the problem. Finally, we generate two test problems with 30 and 60 non-dummy activities to validate the performance of the proposed approach and analyze the sensitivity of the results to different parameter settings.

Grid-Based Heuristic for Two-Dimensional Packing ProblemsTo solve two-dimensional (2D) rectangular packing problems, we [Bui, Abbass, Baker, Barlow, Bender, and Sarker] introduce a new spatial method based on the discretization of the container into a grid of cells with predefined resolution. Before an item is added, grid cells are checked whether they can accommodate the item. If an appropriate empty cell cluster is found, the item is added and moved towards the bottom-left corner of the container. This placement and sliding method is supplemented by a heuristic that orders the items according to descending size. Order and rotation of items can be improved by hybridizing the heuristic with a genetic algorithm (GA) in which a population of order-rotation chromosomes is evolved.

The method is tested on 47 benchmark problems and compared to other methods in the literature. This shows that it is fast and performs very well in finding high quality solutions. Particularly for large problem sizes, it outperforms some of the currently leading methods, such as heuristic recursive (HR). The hybridization with the GA meta-heuristic results in further performance improvements.

Figure 6: Classification ability of the model across three objectives


User- and Application-Centric Multihomed Flow ManagementWe addressed the problem of network selection and flow distribution for a multihomed mobile device. We argue the benefits of a holistic approach which considers user- and application-centric metrics such as quality, energy consumption and monetary cost, rather than the commonly used network-centric metrics. We thus introduced the multihomed flow management problem which combines network selection, flow distribution and application flow awareness. We formulated it as a constrained optimisation problem and compared it to commonly used techniques: single network selection and load balancing. For selected interactive applications, we used empirical network measurements to evaluate the optimal solutions obtained by the three approaches. We showed that, by exploiting the flexibility of application parameters, it is possible to achieve the potentially conflicting goals of maintaining high application quality while reducing both the power consumption and cost of network use. The investigators of the project are M. Maher (SEIT, UNSW-Canberra), O. Mehani (UNSW and NICTA and INRIA), R. Boreli (UNSW and NICTA) and T. Ernst (INRIA).

Kangaroo: An Efficient Constraint-Based Local Search System Using Lazy PropagationWe introduced a constraint-based local search system, called Kangaroo. While existing systems such as Comet maintain invariants after every move, Kangaroo adopts a lazy strategy, updating invariants only when they are needed. Our empirical evaluation shows that Kangaroo consistently has a smaller memory footprint than Comet, and is usually significantly faster. The investigators of the project are M. Maher (SEIT, UNSW-Canberra), M.A.H. Newton (NICTA and Griffith U.), D. N. Pham (NICTA and Griffith U.) and A. Sattar (NICTA and Griffith U.)

Large Scale OptimisationIt is very difficult for existing algorithms to solve large problems with many variables. One popular approach to alleviating these problems is to divide the large problems into a number of subproblems, and to then solve these subproblems using independent computer processors. This can be suboptimal because when one subproblem is optimised, it may cause one or more other subproblems to become deoptimised. This occurs because the variables in one subproblem interact with those of another. In this research, we (Hasan, Daryl and Sarker) have identified such dependencies and have tailored the subproblems to limit such dependencies. Results so far, have supported the merits of this approach.

GA for Constrained OptimisationOver the last two decades, many different Genetic Algorithms (GAs) have been introduced for solving optimization problems. Due to the variability of the characteristics in different optimization problems, none of these algorithms has shown consistent performance over a range of real world problems. The success of any GA depends on the design of its search operators as well as their appropriate integration. In this research, we (Elsayed, Sarker and Essam) propose a GA with a new multi-parent crossover. In addition, we propose a diversity operator instead of mutation and maintain an archive of good solutions. To judge the performance of the algorithm, we have solved not only a set of constrained optimization benchmark problems but also a variety of real world optimization problems. The experimental analysis showed that the algorithm converges quickly to the optimal solution and a superior performance compared to other algorithms that also solved those problems. This algorithm has been received the Best Algorithm Award from the Real-world Optimization Problem Solving Competition organized by the IEEE Congress on Evolutionary Computation in 2011.

Figure 7: The effect of the diversity operator on the quality of results


Soft Operations Research and System Dynamics ModellingComplex problems which outmatch human cognitive capabilities are labelled “wicked” or “messy”. Such problems arise in socio-technical, socio-economic and socio-ecological contexts. They confound the most diligent and fervent efforts by leaders of organisations and Governments. When confronting such problems the best we might expect to achieve is to transform an existing problem situation into a form which is more acceptable that which we currently face. Often our failures to fully understand such problems results in failures to formulate effective intervention strategies. In this research, Soft Operations Research (Soft OR) is combined with System Dynamics (SD) modelling to improve stakeholders’ understanding of a wicked problem situation and to facilitate learning about it. The research currently being conducted in the Australian Capital Territory (ACT) by El Sawah, McLucas and Mazanov integrates Soft OR methodologies and SD modelling to aid understanding with a view to ultimately re-shaping the behaviour of water consumers and enabling water resource managers to develop highly effective strategies. The first stage of this research, which involved capturing and analysing how consumers perceive their roles in influencing the dynamic changes in water consumption, is now complete. Similar analysis of the roles of managers has been completed. The cognitive maps of consumers and managers have been used to guide the development of a set of causal maps, an example of which is included in the Figure below. Causal mapping guided the development of series of SD models and computer simulations through which players in the roles of either consumer or manager, set out to discover how the dynamics of water consumption and supply play out over time and how they might intervene to achieve desirable targets. SD models which incorporate both the ACT’s water supply and demand for water have been validated against historical data for the past 30 years. These SD models provided the basis for developing computer simulations through which both consumers and managers have been able to test the efficacy of their own strategies for managing the ACT’s limited water resources. A recently completed pilot study demonstrated that players achieved significant learning through playing these computer simulations. During the next stage of this research the computer simulations will be made publicly accessible. This next stage will seek to establish the potential use of computer simulations in enhancing learning and re-framing public attitudes about the consumption of scarce water resources. These simulations are expected to be publicly accessible soon.

OR in Bioinformatics Multiple sequence alignment is one of the most important issues in molecular biology as it plays an important role such as in life saving drug design. In this paper, we (Naznin, Sarker and Essam) divide given sequences into two or more subsequences and then combine them together in order to find better multiple sequence alignments by applying a new GA based approach to the combined sequences. We also introduce new ways of generating an initial population and of applying the genetic operators. We have carried out experiments for the BAliBASE benchmark database using the sum of pair objective function with the PAM250 score matrix. To evaluate our proposed approach, we have compared with well known methods such as T-Coffee, MUSCLE, MAFFT and ProbCons. The experimental results show that better multiple sequence alignments may be obtained with higher number of divisions, however the computation time increases with the number of decompositions. The overall performance of the proposed Decomposition with GA (DGA) method is better than the existing methods and the GA method (without decompositions). A paper from this research has been accepted for publication in the IEEE Transactions on Evolutionary Computation (ERA A*) in 2011.


» Opto-ElectronicsSEIT AcademicsA/Prof Charles Harb Prof Elanor Huntington Dr Greg MilfordProf Ian PetersenMr Trevor Wheatley

SEIT Postgraduate StudentsMs Kathryn ConroyMs Katanya KuntzMr Mohammad MabrokMr Rohit RamakrishnanMr Karam ChandMr Peter Kuffner

SEIT Research StaffDr Toby BoysonDr Abhijit Kallapur

Other Collaborators

Centre for Quantum Computer Technology, Australian Research Council

Loyola University New Orleans, LA, USA

M. Calzada, T.G. Spence

Macquarie University, NSW, Australia

Y. He, B.J. Orr

Australian Federal Police, ACT, Australia

K.P. Kirkbride

ACQAO, The Australian National University

J. Janousek, H-A. Bachor

Department of Physics, Denmark

P. Buchhave

Los Alamos National Laboratories, Los Alamos, NM, USA

D.S. Moore

Department of Applied Physics and Quantum Phase Electronics Center, School of Engineering, The University of Tokyo, Japan

A. Furusawa, H. Yonezawa, D. Nakane, H. Arao

Institute for Quantum Computing, University of Waterloo, Waterloo, ON, Canada

D. W. Berry

Perimeter Institute for Theoretical Physics, Waterloo, ON N2L 3G1, Canada

D. T. Pope

Department of Physics, Centre for Quantum Computing Technology, University of Queensland, QLD, Australia

T. C. Ralph

Centre for Quantum Dynamics, Centre for Quantum Computing Technology, Griffith University, QLD, Australia

H. M. Wiseman

Research DescriptionThe Opto-Electronics research group conducts fundamental research into potentially high-payoff applications of opto-electronic systems. The Opto-Electronics group receives financial support from the Australian Research Council through the Linkage Projects, Discovery Projects, and Centres of Excellence Schemes. The group is a member of the ARC Centre for Quantum Computation and Communication Technology and receives additional financial support from the University of New South Wales and the Australian Federal Police. The following paragraphs discuss the research report for 2010.

Nonlinear estimation of ring-down time for an experimental Fabry-perot cavityThis research applies the estimation techniques of a nonlinear discrete time extended Kalman filter to estimate the ring down time for an experimental optical cavity for the purpose of cavity ring down spectroscopy (CRDS). The cavity used is a Fabry-Perot optical cavity, which is a hollow tube, fitted with two highly reflective mirrors. When the input laser frequency matches the resonant frequency of the cavity, it is said to be in lock with the cavity. Any deviation between these frequencies is characterized in terms of the detuning parameter ∆ and is an undesired effect. If the light coupling into the cavity is interrupted, light inside the cavity continues to resonate and gradually decays in intensity. This intensity information is recorded to study the decay of light inside the cavity as a function of wavelength. The time taken for the light intensity to decay to 1/e times its initial value is termed as the decay time τ. This decay time depends upon the reflectivity of the mirrors mounted inside the cavity and losses due to the sample contained within the cavity which directly dictates the amount of optical absorption or scatter. Hence, an estimate of τ in such a spectroscopic technique can be used as a molecular detector in chromatographic systems and for applications in molecular fingerprinting which involves detecting various chemicals, such as explosives and their related compounds.

Though nonlinear least square methods such as the Levenberg-Marquardt (LM) algorithm can handle system noise more effectively but is known to limit the data throughput to below 10Hz. Since the estimation for τ is needed in real time, this issue with the throughput of the LM method motivates us to apply better estimation techniques. One such method for the estimation of nonlinear systems is the extended Kalman filter (EKF), which was considered during this research. The cavity was modeled in terms of the amplitude and phase quadrature variables and the data for the estimation process was obtained from a CRDS experimental setup in terms of the light intensity at the output of the cavity.


The cavity was held in lock with the input laser frequency by controlling the distance between the mirrors within the cavity by means of a proportional-integral (PI) controller. The cavity was purged with nitrogen and placed under vacuum before chopping the incident light at 25KHz and recording the light intensity at its output. In spite of beginning the EKF estimation process with uncertainties in the initial value for the decay time constant, its estimates converged well within a small neighborhood of the expected value for the decay time constant of the cavity within a few ring-down cycles.

A Stability Result on the Feedback Interconnection of Negative Imaginary Systems with Poles at the OriginHighly resonant structural modes in machines and robots, ground and aerospace vehicles, and precision instrumentation, such as atomic force microscopes and optical systems, can limit the ability of control systems in achieving a desired level of performance. This problem is simplified to some extent by using force actuators combined with collocated measurements of velocity, position, or acceleration.

The use of force actuators combined with velocity measurements has been studied using positive real (PR) systems theory for linear time invariant (LTI) systems. Many systems that dissipate energy fall under the category of PR systems. For instance, they can arise in electric circuits with linear passive components and magnetic couplings. However, PR theory can not be used in the cases of position or acceleration measurements. In the same time, the position measurements are become widely used specially in the nanotechnology systems which known as nano-positioning systems. The use of force actuators combined with position and acceleration measurements can be studied using negative imaginary (NI) systems theory.

Many practical systems can be considered as NI systems. For example, such systems arise when considering the transfer function from a force actuator to a corresponding collocated position sensor (for instance, a piezoelectric sensor) in a lightly damped structure. Also, in cavity looking in optical cavities experiments can be formulated as NI system, since the PZT in this system is an actuator collocated with the cavity which is the equivalent of a position sensor.

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Figure 1: Proposed CRDS setup with an EKF estimator and a controller.

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Figure 2: Block diagram of CRDS experimental setup: The red and green lines represent optical signal paths whereas the blue line represents the path for electronic signals. Also, ISO is the Faraday isolator; MMO are mode matching optics; HWP are half wave plates; EOM is the electro-optic modulator; AOM is the acousto-optic modulator; MOD1 is the RF generator and amplifier for phase modulation; MOD2 is the signal generator and amplifier used to generate the chopping waveform; M1 and M2 are beam steering mirrors; PCB is a polarizing cube beamsplitter; PD are photodetectors; QWP is a quarter wave plate; SERVO is the controller; HV AMP is a +/- 200 V amplifier to drive PZT, the piezoelectric actuator that controls the cavity length.

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Figure 3: A comparison of EKF and LM estimation results for t at the end of each ring-down cycle, plotted against the expected true value for τ.


In this work, a new NI definition is presented to capture the class of systems that have poles at the origin. Also, a new stability conditions are derived for this case. The importance of this extension comes from that the new formulation of the NI theory will allow for many engineering systems and applications to be considered as a NI systems. Such applications include low-friction, free rigid-body motion, such as single-axis spacecraft rotation, rotary crane motion , flexible link manipulator and in the case of dual-stage hard disk drive.

Enforcing Negative Imaginary Dynamics on Mathematical System ModelsSince flexible structures with collocated force actuators and position sensors are typically NI, NI systems theory can be effectively applied to these systems. For systems involving flexible structure dynamics, it may be difficult to obtain an exact system model by constructing differential equations from first principles for such systems. An alternative method for obtaining a mathematical system model is by means of system identification. However, the resulting mathematical model may not exactly describe the true dynamics of the underlying system.

Identified system models can sometimes lead to mathematical models that do not reflect the actual characteristics of the underlying system. For example, the process of system identification when applied to linear time-invariant (LTI) systems which are known to be NI might lead to a model which is not NI. The same problem occurs in the identification of passive systems and typically due to the basis parametrization imposed by system identification. In such cases, the system model should be perturbed to enforce the underling NI dynamics.

This work provides two methods for enforcing NI dynamics on such mathematical models, given that it is known that the underlying dynamics ought to belong to this system class. Also, we presents an application of the NI enforcement schemes to a practical system arising in cavity ring down spectroscopy system.

The Development of Super Clip Mathematics for the Fourier Transform Infrared SpectrometerThe availability of a wide frequency bandwidth as well as rugged instrument design make Fourier transform infrared (FT-IR) spectroscopy a reliable option for remote detection applications. However, a commonly encountered difficulty in field applications of this technology is the collection of a background spectrum representative of the environment being sampled. Temperature disparities or temporal differences between the spectra may result in artifacts in the subsequent absorbance spectrum. Atop the issue of quality background acquisition, there are other standard complications involved with substance identification in a non-stationary environment. Baseline drift, excess signal noise, extraneous absorbance features and wavenumber shifting are among some of the most commonly encountered issues.

The development of super clip mathematics addresses the issue of background collection by the manipulation of the FT-IR raw data in a manner that enables the calculation of an absorbance spectrum from a single interferogram. Super clip apodization (SCA) has previously been discussed in the literature as a method to calculate a background spectrum using only the central burst of the interferogram; but has all but been dismissed because of the generally narrow field of applicability suggested in the literature. Complementary super clip apodization (CSCA) is a sister technique to SCA where the central burst of the interferogram is omitted and spectral features on a generally flat baseline remain.

Both SCA and CSCA fall under the umbrella analysis technique in active development at UNSW Canberra, called super clip mathematics. These methods can be used individually or in combination to calculate a spectrum, but their successful implementation relies on the use of an iterative spectral comparison routine. Figure 4 is a process flow diagram of the super clip mathematics algorithm in its current manifestation. In this case, SCA and CSCA are used in combination so the lengths of the complementary truncation functions are being optimized in series. Absorbance spectra are iteratively calculated and compared to a reference using an evaluation metric such as Euclidian distance or the Pearson Correlation Coefficient. The spectrum calculated with the “best” score is selected as optimal. Therefore, the user must have an a priori knowledge of the analyte they intend to detect.


Current research suggests that the combination of SCA to calculate a background spectrum with CSCA to calculate a sample spectrum is more robust than SCA as previously discussed in the literature. This is largely in part to the judicious optimization of the truncation lengths of the interferogram. Furthermore, in a quantitative study of the nitromethane asymmetric stretch, it has been concluded that super clip mathematics is applicable for analytes with a full width half maximum (FWHM) significantly larger than originally postulated. This study has also demonstrated a robustness of the method against extraneous noise as well as wavenumber shifting.

Time domain analysis in this fashion is generally difficult, as interferometric manipulation parameters are often interdependent. However, a current direction of this work is to investigate and characterize these interrelationships; such as those that exist between the calculated spectrum and various instrumental configurations. Furthermore, a motivation to apply super clip mathematics to real-time applications requires further optimization of the iterative spectral comparison routine and eventual implementation on a digital signal processor (DSP) or field programmable gate array (FPGA) device.

Improved Signal Processing for Cavity Ringdown SpectroscopyCavity ring-down spectroscopy (CRDS) is a sensitive spectroscopic technique that can be used to measure absorption due to weakly absorbing or dilute samples. In a CRDS measurement, light (generally this is from a laser, but broadband techniques have been demonstrated) is coupled into an optical cavity formed by two or more mirrors. Upon extinguishing the incident light, the field within the cavity, I(t), decays exponentially: traditional instruments focus on fitting this decay using, typically, non-linear least squares fitting algorithms: this place a limit on the throughput, and thus the achievable sensitivity of the technique

We have developed a Fourier-transform based signal processing method for laser-locked Continuous Wave Cavity Ringdown Spectroscopy (CWCRDS). Rather than analysing single ringdowns, as is the norm in traditional methods, we amplitude modulate the incident light, and analyse the entire waveform output of the optical cavity; our method has more in common with Cavity Attenuated Phase Shift Spectroscopy than with traditional data analysis methods. We have compared our method to Levenburg-Marquardt non linear least squares fitting, and have found that, for signals with a noise level typical of that from a locked CWCRDS instrument, our method has a comparable accuracy and comparable or higher precision. Moreover, the analysis time is approximately 500 times faster (normalised to the same number of time domain points). Our method allows us to analyse any number of periods of the ringdown waveform at once: this allows the method to be optimised for speed and precision for a given spectrometer.

Locked Cavity Attenuated Phase Shift SpectroscopyCavity Attenuated Phase Shift Spectroscopy (CAPS) is a variant of Cavity Ringdown Spectroscopy (CRDS) and was the first of the cavity enhanced methods to be applied to measuring mirror reflectivities, but was the last to be applied to spectroscopy. A CAPS measurement offers several advantages over a traditional CRDS measurement, including a high throughput and a narrow detection bandwidth. CAPS, has, however never become popular in the literature: while PCRDS and CWCRDS rapidly grew in popularity after the original papers, with many improvements on the original techniques, CAPS experiments still use the same setup as that of the original work in the early 1980’s. This lack of development has resulted in the sensitivity of the technique not improving in the same way as that for CRDS, where modern spectrometers are several orders of magnitude more sensitive than the original instruments.

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Figure 4: Process flow diagram for the iterative spectral comparison algorithm. In this scenario, SCA and CSCA are being used in combination.


We have developed a new variant of CAPS that involves actively locking the incident light to one of the resonant modes of a moderately high finesse cavity. Rather than using a lock-in amplifier and a ratiometer to measure the phase shift imparted by the cavity, as is the norm in traditional CAPS experiments, we have developed digital signal processing that should allow us to process the data from our instrument in real time. We report the best sensitivity for a CAPS measurement, a Minimum Detectable Absorption Limit(MDAL) of the order of 10-10 cm-1 Hz -1/2, achieved with only 4 milliseconds of data: this measurement is two orders of magnitude better than any sensitivity reported in the literature.

Robust quantum phase estimation of a weak coherent state of lightQuantum parameter estimation (QPE) is the problem of estimating an unknown classical parameter, usually an optical phase shift, of a quantum system. QPE is at the heart of many fields such as gravitational wave interferometry, quantum computing and quantum key distribution. Recently, it has been demonstrated experimentally that adaptive quantum smoothing technique, employed for estimation of the dynamically varying stochastic phase shift of a weak coherent state, yields an estimate with a mean-square error of up to 2.24±0.14 times smaller than non-adaptive filtering (the standard quantum limit). Quantum smoothing is a time-symmetric estimation technique that takes into account both past and future observations and can be more precise and accurate than only filtering, that considers only the past measurements.

The aforementioned adaptive experiment made use of a feedback filter that is sub-optimal in a more general setting for the noise process considered. The new research described here modeled the noise process and the measurement involved in the experiment in the Kalman filtering framework to design the feedback filter that would be optimal in the general case. Also, it is physically unreasonable to set absolutely precisely to desired values, the parameters underlying the noise process considered. Hence, it is desired to further extend the Kalman filter model to allow for uncertainty in the underlying parameters and re-design the feedback filter that would be robust against uncertainty in the linear model.

Figure 5 illustrates the comparison of the mean-square phase estimation error for the Kalman filter with that for the existing filter. The graph is a plot of the mean-square estimation error versus a suitably scaled parameter for the underlying model. As can be seen, in the lower values regime for the considered parameter, the existing filter behaves as good as the optimal Kalman filter; however, as the parameter value rises, the Kalman filter has significantly less mean-square error, and therefore superior performance, than the existing filter. The red vertical line indicates the value of the parameter as used for the adaptive experiment.

In order to make the filter robust to uncertainties in one of the underlying parameters, the Riccati equation approach to building a guaranteed quadratic cost state estimator for linear uncertain systems was adopted. Figure 6 (a, b and c) demonstrates the comparison of the mean-square estimation error between the robust filter and the Kalman filter for 5%, 50% and 80% uncertainties, respectively. For 5% uncertainty, there is not much noticeable difference between the two cases.

However, with increased uncertainties of 50% and 80%, the Kalman filter tends to significantly deteriorate as compared to the robust filter at the positive end of the uncertainty window. Furthermore, for the 80% case, the robust filter beats the standard quantum limit throughout unlike the Kalman filter.

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Full analysis of Schrodinger kitten generationNon-Gaussian states such as Schrödinger cat states have attracted intense interest for quantum continuous-variable (QCV) information processing, since it provides a basis for entanglement distillation, universal quantum computing, and proposed loophole-free tests of Bell’s inequalities. Schrodinger cat state generation at telecommunication wavelength is particular important for long-distance quantum key distribution (QKD).

Optical cat states can be generated using a photon-subtracted squeezed vacuum state. A strong signature of the quality of such a state is when the state has a negative Wigner function. A negative-valued Wigner function such a cat state has been experimentally demonstrated around the wavelength of 860 nm. However, the experimental result for cat state generation at 1550 nm is still limited by imperfections in the experiment such as: non-photon-number-resolving ability, inefficiency and dark count of the projected photon number detector, which have been discussed by many researchers. But even if these factors were considered, experimental results reported at 1550 nm are still not as good as that at 860 nm. Therefore, we aim to develop a more comprehensive model of the experiment to quantitatively investigate the impact of experimental imperfections in the experiment.

A mathematical model was developed that covered the possible imperfections of the input state, projected photon number detector and the interactions between them. All these imperfections degrade the properties of Schrodinger cat state. We analyzed our experimental results based on the developed model. Figure 7 shows the photon number distribution of the input state as reconstructed from the experimental data, which is quite similar to the photon number distribution predicted by our model as shown in figure 8. The predicted photon number distribution for the photon-subtracted squeezed vacuum is shown in Figure 9, which is also similar to the experimental results.

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» Remote SensingSEIT AcademicsDr Xiuping Jia Dr Mike Ryan A/Prof Mark Pickering A/Prof Donald FraserDr Andrew LambertA/Prof Tuan Pham

SEIT Visiting FellowsDr Jihao YinDr Xiaofeng Li

SEIT Postgraduate StudentsMiss Chandrama DeyMr Md Al Mamun Mr Mahmudul HasanMr Guangyun ZhangMr Md. Ali Hossain

SEIT Practium StudentsMiss Xi Zhang

Other Collaborators

Faculty of Engineering, UNSW

A/Prof Linlin GeDr Ngai Kwok


Prof John Richards

Geoscience Australia

Dr Adam LewisDr John Schneider

Harbin Institute of Technology, China

Dr Ye Zhang

Harbin Engineering University, China

Dr Liguo Wang

Beijing Normal University, China

Dr Jin Chen

Research DescriptionRemote sensing has been used widely ranging from weather forecasting to land cover change monitoring. It is a field of technology in which sensors are mounted on aircraft or spacecraft platforms and used to acquire images of regions on the earth’s surface. Each optical image is the reflectance of the solar spectrum at a particular range of wavelength. Typically the hyperspectral images are generated by recording the reflectance of ground cover types with approximately 200 spectral bands. The data produced will be processed by computer to extract valuable information for various applications. There are three issues in remote sensing data interpretation: data compression and transmission, data correction and data analysis. These issues are investigated by this group.

Collinearity Effect in Spectral UnmixingMixed pixels exist widely in remotely sensed images due to the inherent heterogeneity of land surfaces and the relatively coarse spatial resolution of remote sensing sensors. The extensive presence of mixed pixels results in failure of traditional hard-classification methods in which a pixel is assumed to belong to only a single ground cover type. Soft-classification techniques were then developed where the abundances (fractions) of the components (endmembers) present in the mixed pixels are quantified. A number of spectral mixture analysis (SMA) methods have been develop over the past decades. SMA has the same mathematical form as multivariate regression analysis, where collinearity is a common problem. We investigates the collinearity effects on the inversion accuracy in SMA quantitatively and analyzes increased collinearity in the nonlinear SMA model, in particular. (X. Chen, et al., “A quantitative analysis of virtual endmembers’ increased impact on the collinearity effect in spectral unmixing,” IEEE Transactions on Geoscience and Remote Sensing, vol. 49, pp. 2945-2956, 2011.)

The collinearity of linear SMA (LSMA) is often not very strong because only distinctive spectra are usually selected as an endmember. However, the collinearity of nonlinear SMA (NSMA) should be considered seriously because the virtual endmembers formed by the interactive term can highly correlate with the true endmembers. The experimental results show the strong increase in variance inflation factor (VIF) when the nonlinear model was used. Simulated results also showed that the NSMA with high VIF was more sensitive to Gaussian noise. The inversion accuracy of NSMA dropped with increasing noise level, even up to a point that the use of LSMA performed better.

Feature Extraction for Efficient Hyperspectral Image Classification Mapping With the advent of hyperspectral remote sensors hundreds of narrow contiguous spectral bands/features can now be captured to provide greater details on the spectral variation of targets than conventional multispectral systems. For instance, AVIRIS sensor simultaneously measures 224 bands with a fine resolution e.g. 0.01µm. However, at present this high dimensional data implies a major challenge for the traditional classification methods. Moreover some bands are highly correlated and not important for a specific application. On the other hand, as the feature space dimension increases, if the size of the training data does not grow correspondingly, a reduction in the classification accuracy of the test data is observed due to poor generalization of the supervised classifier. This effect is known as the Hughes phenomenon. There fore the aforementioned problem needs to be solved by efficient dimensionality reduction.


Two approaches are available to overcome the above problem. One is to apply a feature reduction method to reduce the dimensionality of the input data and the other is to modify the classifier design so that it is suitable for large size data. Feature reduction can be done by selecting an important subset of the originals or transforming the input data to a new space called feature extraction. Some conventional feature reduction approach PCA, LDA, J-M and Bhattacharya distance measure presents obvious limitations and drawbacks including they depend on the training data, ineffective class pair wise treatment and is only reliable for normal like data. To solve and increase the classification accuracy we proposed a dimensionality reduction method (Hossain, Jia and Pickering, IGARSS 2011) which combines feature extraction using PCA and feature selection from the resulting principal components using a mutual information measure. The proposed MI-PCA method selects transformed features (PCs) with higher value of MI as it measures the relevance of the principal components regarding the input classes. Experiments were conducted to evaluate the performance of MI-PCA method when compared with the standard MI, and PCA approach. The result shows that the proposed MI-PCA approach can identify features that can obtain 80% (best among three) classification accuracy for test data.

Multimodal Remote Sensing Image Registration Image registration is one of the important pre-processing step for data fusion, where two or more image data sets are combined for information retrieval. When image data are recorded by sensors on satellites or aircraft they contain errors in geometry. The sources of geometry errors include the rotation of the Earth, and curvature of the earth surface, and uncontrolled variation in the position and attitude of the remote sensing platform. These errors need to be rectified via image registration before data fusion can be conducted. Automatic image registration can be classified into two categories – feature based image registration and intensity based image registration.

Automatic intensity based image registration for images captured by different sensors usually requires the use of information-theoretic similarity measures such as mutual information (MI). Recently a new similarity measure known as Cross-Cumulative Residual Entropy (CCRE) has been proposed for multi-modal image registration in medical imaging applications. We investigated the use of CCRE for multi-sensor registration of remote sensing imagery and the extreme case of registering synthetic aperture radar (SAR) images to optical images. We also proposed a novel extension to the Parzen-window optimization approach proposed by Thévenaz which involves applying partial volume interpolation in the calculation of the gradients of the similarity measure (M. Hasan, M. Pickering, X. Jia, TGRS 2012, Volume 50, Issue 10).

Our experimental results showed that proposed approach which uses CCRE as the similarity measure and partial volume interpolation in the optimization procedure provides superior performance to other approaches investigated.

The scale invariant feature transform (SIFT) is a widely used method for feature based image registration and object recognition. The SIFT method is well known for its ability to identify objects at varying scales and rotations among clutter and occlusion with very fast processing time. The application of SIFT on multi-modal remote sensing images for image registration purposes, however, often results in inaccurate and sometimes incorrect matching. Commonly a very large number of feature points are generated from a remote sensing image but a very small number of feature points are matched giving a high false alarm rate. We proposed a method containing several modifications to improve SIFT feature matching by adapting the characteristics of remote sensing images (M. Hasan, M. Pickering and X. Jia, IGARSS 2012 accepted). The proposed method leads to more matching points with significantly higher rate of correct matches.

Spectral –Spatial based Remotely Sensed Image ClassificationInvestigating spatial information into remote sensing image classification is an important aspect to improve the classified accuracy. Two important ways for the spatial information are texture and contextual information. For the texture, Gabor filter is an effective way to extract texture information. For remote sensing image, its value comes from sufficiently spectral information which means it has multispectral or hyperspectral information with several or even hundreds of bands. If texture bands from Gabor filter are added into the data source, the higher dimensions become a big problem for the classification. A feature extraction method called Kernel Local Fisher Discriminative Analysis is used to solve this problem. This method improves the traditional Fisher Discriminative Analysis by introducing the nonlinear kernel style and at the same time integrating locality preserving projection to keep the data structure (Zhang and Jia, IGARSS 2011). This approach integrates the spectral and texture information together with reducing the complexity of the classification. Fig. 1 shows the comparison of classification results with different methods.

For the contextual information, a method called super pixel based classification is used to integrate the spatially neighbouring information into the classified procedure. This method connects the segmentation and the classification together and do not need to generate accurate segmentation, which is as difficult as accurate classification. The simple majority volt is used to apply the contextual information from the super pixels into the posterior processing of the pixel based classification (Zhang, Jia and Kwok CISP 2011). The ‘salt and pepper’ phenomenon for the pixel based classification has been removed significantly.


Adaptive Markov Random Field (MRF) Approach for Classification of Hyperspectral ImageryThere exist two issues when using conventional MRF for the classification of hyperspectral images. First, when the spectral term uses an MLC, reliable estimation of class covariance is difficult for hyperspectral data if there is inadequate number of training samples available. Second, spatial weighting coefficient controls the contribution of spatial term in the MRF approach, and how to select it automatically is challenging. The spatial component of conventional MRF is implicitly based on the assumption that the neighboring pixels have the same class labels as the central pixel. Each pixel uses the same weighting coefficient for its spatial term regardless that it is on a class boundary or within a homogeneous region. In another word, spatial effect is treated equally for all the pixels. As a result, with a given weight, classification accuracy is improved in homogeneous regions, but pixels at class boundaries are at the risk of overcorrection.

An adaptive-MRF (a-MRF) approach for spectral–spatial classification of hyperspectral imagery is developed (B. Zhang, et al., “Adaptive Markov Random Field approach for classification of hyperspectral imagery,” IEEE Geoscience and Remote Sensing Letters, vol. 8, pp. 973 – 977, 2011). Figure 2 is the flow chat of the proposed method. We introduce a relative homogeneity index (RHI) and use this index to find the suitable weighting coefficient of the spatial contribution for each pixel, in order to improve classification performance. Experiments using both synthetic and real hyperspectral data sets demonstrated the better performance.

a b c d

Figure 1 (a) The original DC Mall image. The Maximum Likelihood classification results (b) using reduced features based on PCA (b) using reduced spectral features based on kernel LFDA, and (c) using reduced spectral features plus colour texture feature based on kernel LFDA.

Figure 2. Flowchart of the proposed a-MRF procedure.


» Social Networks Group (SNG)

SEIT Academics Dr Rob StockerProf. Hussein AbbassMrs Jenny BackhouseDr Michael (Spike) BarlowDr Gary MillarDr Ed Lewis Dr Tim Turner

SEIT Postgraduate StudentsMs Helen Gilroy Mr HC Lim Mr David KernotMs Sue BurdekinMs Mai Shouman

Collaborators

INTERNATIONAL

University of Arizona (Tuscon AZ USA)

Prof H Randy Gimblett (School of Renewable Natural Resources)

University of Southern California (Los Angeles CA USA)

Prof Thomas W Valente (Keck School of Medicine)

University of Aizu (Aizu-Wakamatsu-shi Fukushima-ken JAPAN)

Dr Henry Larkin

AUSTRALIA

Australian National University (Canberra ACT)

Dr Rob Ackland (The Australian Demographic and Social Research Institute ADSRI)Dr Jennifer Badham (National Centre for Epidemiology and Population Health)Dr Al Klovdahl (Sociology, College of Arts and Social Sciences)Dr Dirk Van Rooy (Department of Psychology)

Charles Sturt University (Bathurst NSW)

Prof Terry Bossomaier (Centre for Research in Complex Systems - CRiCS)

CSIRO (Newcastle)

Dr David Cornforth (CSIRO Energy Centre)

Monash University (Clayton Vic)

Prof David G Green (School of Information Technology – CSSE)

Industry Collaboration Projects

NATIONAL

Dr Sean Bergin (DSTO, Effects-based Modelling Unit, Edinburgh South Australia)

Research DescriptionThe Social Networks Group (SNG) conducts theoretical and applied research that is primarily focussed on network structure and function. Its foundations lie in considering social organisation, communication and interaction and how that research can be used to describe and/or predict complex (social) system behaviour. A regular newsletter is to be circulated to members via the official web site and Wiki (under construction) that provides more detailed information about SNG.

MissionThe Social Network Group (SNG) will provide a service to social network researchers that enables key processes for effective collaboration, communication, project initiation and completion, publication, and promotion over national and international boundaries.

RESEARCH PROJECTS

Landscape and behavoural factors in cross-border migrationNational security has become an increasingly important concern for countries where borders are bounded by or are in close proximity to other countries whose political, ideological and cultural perspectives are very different. In particular, where such reasons seem to encourage illegal migration and/or criminal activity, management of such trafficking is of great concern to respective governments. What factors influence such individual and group behaviour? We (Dr Rob Stocker, Prof Randy Gimblett and Dr Spike Barlow) explore similarities and differences between events in the USA and Mexico and in Australia and Indonesia for valuable insights. From these insights we develop a multi-agent simulation model to examine (in silica) factors that influence landscape and patterns of behaviour for application to other locations. We propose to take a “serious-game” approach to developing the model so as to capture the strategic and tactical planning of the players. This project (initiated in 2009 and supported by SSP Leave in 2010) is continuing through 2011.


Analysis of social structure in aberrant social groups People congregate and merge together to form large groups for a variety of reasons, for example at sporting events, entertainment venues, in recreational activities and others. Crowd behaviour can move from being benign to destructive (to both environment, others and self) within short timeframes depending on a variety of stimuli. Some groups deliberately engage in anti-social and confrontational behaviour whilst others deliberately engage in practices that are intended to harm and destroy. What network structures and patterns of communication are evident in groups whose activities focus on an intent to disrupt accepted social order? This project initiated in 2010 (Ms Helen Gilroy; Dr Rob Stocker; Dr Tim Turner; Dr Spike Barlow; Dr Ed Lewis) has evolved to concentrate on terrorist and criminal networks and employs novel data extraction and analysis methodologies to conduct comparative analyses of the network characteristics. Our results so far demonstrate that social network analysis (SNA) is productive for the examination of such group activity (Figure 1). It includes comparisons between different aberrant social groups and the structure of member interactions that lead to their activities. This will enable the construction of explanatory and predictive simulation models. The project will be completed by March 2012.

Trust and social moral norms and the impact of networks and agentsMr HC Lim completed his PhD Thesis, submitted it for examination in January 2011 and his doctorate will be confirmed at the 2011 Graduation Ceremony. The project: “Interplay of Ethical Trust and Social Moral Norms in Signal-Behaviour Computational Social Processes: An Investigation of Agents and Networks Effects” developed an heuristic formalism to examine the process-structure interplay between agent based and network based effects on social moral norms and trust behaviours. The simulation (Figure 2) demonstrated that patterns of connectivity and agent characteristics have significant influence.

Figure 1 Network Map showing identified cut-points and critical bridge

Figure 2. Conventional findings suggest that the underlying structure of social networks has assortative mixing of degrees. Here, experimental results show both assortative (on the left) and disassortative (on the right) mixing of degrees with different network densities.


Affective and cognitive constructs in social networksMembers of social groups bring different life-skills, knowledge and capabilities to any groups to which they belong. Such experience is important in the formation of the group and its maintenance. In particular, the influence of peer pressure on adolescent students in the uptake of cigarette smoking (and other substance experimentation) has been shown to be significant. The SNG team (Mr David Kernot, Dr Rob Stocker; Dr Gary Millar; Prof Tom Valente) initiated this project prior to SSP Leave in 2010 undertaken by Dr Rob Stocker to University of California in Los Angeles to collaborate with Prof Tom Valente from the Hecks School of Medicine. Empirical interview data on congitive and affective attributes of a population were gathered for preliminary analysis. M Phil Student Mr David Kernot is using this data to develop formal algorithms to extract specific linguistic cues that are indiciative of the relationship between communication and cognitive processing. The project will be expanded to a PhD Research project in 2012.

Social Networks: Links and Language (Book of Edited Chapters Project)The growth in our understanding of networks, especially human social networks, has been quite remarkable over the last decade. But equally remarkable is how the networks themselves have been evolving, driven in part by the many new tools in cyberspace. Along with these new communication tools come increasing numbers of changes to language and lexicography. English spelling in text messages is nothing like the spelling we learn in school, so far at least, while groups differentiate themselves more and more by linguistic twists and turns, new words, slight variations in grammatical usage – the so not cool phenomenon.

This book co-authored by Dr Rob Stocker and Prof Terry Bossomaier(CRiCS) discusses social networks and their integration with communication and language (Figure 3). Although accessible to a wide audience, it contains sufficient technical detail to serve as a starting point for advanced undergraduates and postgraduates and reflects the content of the 5th Biennial Complex Systems Research Summer School at the Centre for Research in Complex Systems (CRiCS) in Bathurst NSW. The seven chapters of the book cover three broad areas: technical fundamentals; complexity and social networks; and communication and language and will be published in 2012.

Figure 3. An overview model describing the process of social interaction between individual human participants, emphasising key human characteristics and the importance of language in connectivity patterns between interacting actors in a dyad.


» Software EngineeringSEIT AcademicsDr Chris Lokan Dr Gary Millar

SEIT Postgraduate StudentsMr Irman Hermadi Mr Eugene Suchcicki

Other Collaborators

Zayed University, U.A.E.

A/Prof Emilia Mendes

Research DescriptionResearch in Software Engineering aims to improve our ability to develop high-quality software as productively as possible. It is a wide discipline, in which a diverse range of proposals is made for how things can be done “better” – but relatively few claims are backed up by evidence. There is growing realisation of the importance of empirical software engineering: conducting experiments and using measurement to demonstrate the advantages of different techniques and to improve our ability to manage the software development process.

The Software Engineering research group concentrates on empirical software engineering, and software project management. In particular, the group has interests in measurement. Some research is fundamental: what is good or bad about particular measures, and why? Other research looks at how measurement can be applied in software project management, for in-house developments and for software acquisition projects.

Test case generation for path coverage using evolutionary algorithms“White box” software testing involves running a program and seeing which parts of the program were executed; if there are any unreachable parts of the program after thorough testing, it is likely that the program contains potential logical error(s). The weakest form of white box testing is “statement coverage”, which aims for every statement of code in the program to be executed at least once. A stronger form is “branch coverage”, which aims for each branch of each decision to be exercised at least once. The strongest form is “path coverage”, in which the aim is to execute every logical path through the program. This is hard in the presence of loop(s), because executing a loop once before loop termination is considered to be a different path to twice through the loop, and so on.

The main task in white box testing is generating a set of test cases that will cause different paths through the program to be executed. Since this is expensive, there is much interest in automating it. Recently several researchers have successfully applied genetic algorithms (GA) in generating test data for white box testing. Most of this research has concentrated on statement coverage or branch coverage; there is very little on path coverage.

The objective of our research is to investigate the application of GA, and other evolutionary algorithms, for test data generation for path coverage. Initial experiments showed that GA is effective for this problem, and identified the parameters with the greatest impact on performance.

One current line of research investigates how to decide whether a path is infeasible when no test data has been found for it after a period of searching. An approach is proposed (based on software reliability models) for deciding when to stop searching, assuming that paths that have not been covered are infeasible, based on the history of how many previously uncovered paths are covered in each generation of searching. An arbitrary limit on the number of generations for which to search is not needed; the searching performance itself defines the limit. Different rules can be used to decide when to stop searching, enabling a trade-off between search time and paths covered. Results have shown that under the best of the decision rules investigated, searching can stop after few generations with very little error in terms of paths that really are feasible being incorrectly deemed infeasible. (I. Hermadi, C. Lokan and R. Sarker, “Software Reliability Model for Stopping Criteria in Evolutionary Path Testing”, under review).

A second line of research investigates whether hybrid search methods, combining GA with various types of local search, is suitable for path testing. Preliminary results show that combining GA with local search makes little difference to the number of paths covered, but reduces the search time to find test data to cover those paths.


» Viable Systems Planning, Strategy and Architecture

SEIT AcademicsDr Edward LewisDr Gary Millar

SEIT PhD CandidatesCecilia RidgleySlade BeardMohammad EsmaeilZadehNizami Jafarov

Research DescriptionThe Viable Systems Planning group carries out applied research into governance (especially strategy or policy) a nd architecture of enterprises, using the principles of cybernetics and the practices of Enterprise Architecture/ Enterprise Engineering.

Human Enterprise ModelSlade Beard has prepared the Human Enterprise Model (see Figure 1) during his work for his PhD. This model has been tested during his professional work as an Enterprise Architect responsible for designing several Emergency Management or Command and Control Centres. His model is currently being tested in the design of a new Cancer research and treatment hospital in Melbourne. It serves to integrate the essential, yet often overlooked, aspects of facilities and human behaviour in the design of an Enterprise Architecture.

Figure 1. Human Enterprise Model


Advances in Enterprise Architecture EducationEd Lewis produced a report, at the request of the Department of Defence, about the sate-of-the-art in the Enterprise Architecture discipline. The report was to support the development of a curriculum for Enterprise Architects. He visited over 30 institutions in the US, Europe, and the UK that were involved in presenting courses or in using the results of Enterprise Architects, including the Department of Defense and the Ministry of Defence. The contents of the report have been incorporated into the website (www.layrib.com) supporting the Systems Planning body of knowledge that the team is preparing.

The Learning Framework that was developed as part of the study is based upon Cec Ridgley’s recently awarded PhD entitled A Systems Approach to Ethical Decision making. This Framework is shown in Figure 2. Learning framework for enhancing Enterprise Architecture.

Viable Governance ModelThe team have published papers about the Viable Governance Model that Gary Millar developed for his DIT. This model, shown in Figure 2, applies Stafford Beer’s Viable Systtems Model to the corporate governance of Information Technology. It provides the theory behind many of the empirical findings about various governance mechanisms, including organizational structure and the roles of the Board.

Figure 2. Learning framework for enhancing Enterprise Architecture

Figure 3. Structure of the Viable Governance Model


Enterprise Architecture PrinciplesFollowing on from the work about the Viable Governance Model, the team – particularly Mohammad EsmaeilZadeh – is developing a systematic method for generating Enterprise Architecture principles. This method is based upon the cybernetic principles of requisite variety, recursion, and control.

Viable Service Oriented Enterprise ArchitecturePhD Candidate Nizami Jafarov is looking at the challenges parallel technological innovations might bring to an Enterprise in times of intra-Enterprise and inter-Enterprise integrations in public, private and hybrid Cloud eco-systems. In his work, he is linking the Viable System Model derived from the Cybernetics theory with the Service Oriented Enterprise Architecture paradigm to build a novel Viable Service Oriented Enterprise Architecture as a remedy against integration risks and as a tool for enterprise decision makers and architects.

Figure 4. Domains of the Viable Service Oriented Enterprise Architecture


» Systems EngineeringSEIT AcademicsDr Mike Ryan Dr Alan McLucasMs Brownwyn Jones

Research DescriptionThe Systems Engineering research group conducts theoretical and applied research in the fields of systems thinking and modelling, systems engineering, and requirements engineering. The following paragraphs summarise a number of the group’s projects in 2011.

The Utility of Decomposition as a Systems Engineering ToolAlmost without exception, any writing on systems engineering (whether text book, research paper or standard) begins with the same central thesis: humans address (within our limited intuition) complex systems (that are beyond our limited intuition) by using abstraction and decomposition within a hierarchical framework. Abstraction allows us to focus on the essential information at any level in the hierarchy; decomposition allows us to break each level of the hierarchy down into the next level of detail. Despite the fact that decomposition is ubiquitous in systems engineering literature, the methodology is commonly rejected by the systems engineering community as a tool of Cartesian reduction, with all its inherent limitations from a systems thinking perspective, and is therefore seen to be inappropriate to systems ideas and methods. Unfortunately, the discussion fails to identify any robust alternative approaches so considerable confusion exists in the systems engineering community with regard to the application of decomposition, particularly to systems design.

This work revisits the role of systems engineering, the nature of systems, and systems design, in order to show the utility of decomposition as a systems engineering tool. It highlights that systems engineering is concerned solely with the design (composition) of human-made systems in which the ability to decompose the system into its constituent elements and interfaces is axiomatic. Decomposition then supports the designer in making choices regarding the optimal combination of system attributes that will best meet the system’s purpose and thus is a valuable tool when applied in the correct context to an appropriate problem. In terms of a continuum of effort in the design of a system then, scientific investigation and systems engineering are shown to have different but complementary contributions and support tools. When viewed against the system lifecycle, scientific investigation reduces an unknown system in order to determine what it comprises and how it works.

That knowledge then provides the start point for systems engineering to decompose and define a system, prior to selecting the optimal architecture to meet the system’s purpose. Decomposition is a valuable and valid contributor to the systems engineering effort; particularly so in the absence of any robust, documented alternatives.

Application of MBSE to Requirements Engineering—Research ChallengesModels and simulations have always played an important role in engineering and systems engineering. Physical scale models, full-sized models, and computer models are commonly used in all forms of engineering and design. In recent times, interest in modelling has increased to span the full system lifecycle and there has been a significant focus on Model-based Systems Engineering (MBSE). The extension of formal modelling into all phases, and particularly the conceptual design phase, of a system development is a significant step and proponents of MBSE suggest that it will provide considerable benefits.

The application of modelling requires considerable care, however. A model, by its nature, is only an abstraction of a real-world domain in which certain parameters have been chosen by the modeller for implementation in the model. Since it is not possible to model all of the parameters of the real world, a model is therefore always an abstraction (deliberately or not) of a real-world domain. The specific nature and level of abstraction mean that a model is only able to serve the purpose for which it is designed—application of the model outside those constraints can be misleading at best and potentially dangerous.

In this work we focus on the use of MBSE to support requirements engineering. We first describe a suitable framework within which to consider the utility of MBSE to support requirements engineering. We then outline the principal activities undertaken as part of requirement engineering and identify the potential of MBSE to support each of those activities, as well as identifying a range of challenges that must be addressed before MBSE can be applied usefully to requirements engineering.


Improving Security Systems Terminology: A Systems Engineering Approach

The specification and design of modern security systems are hampered by terminology that is overlapping, recursive and often contradictory in nature. The terms and associated definitions used by prominent standards organisations present a confusing mix of actions, states and governance functions that lack commonality in meaning and interpretation and tend to be specific to one problem domain (mostly electronic or cyber security).

Consequently, despite the critical nature of security in the design of almost all systems—and the increasing criticality of security systems themselves—the current set of security terms and definitions is of little use to stakeholders when articulating their requirements, nor to systems designers when developing system requirements. This work begins by examining the definitions and terms applied to security and to security systems. A systems engineering approach of functional decomposition is then used to analyse the set of terms and to illustrate how such terms are of little use in systems design. A new definition of security is proposed, from which a suitable set of security terms is decomposed. This new set of security definitions incorporates the intent and meanings of current security terminology, and is not only applicable to cyber security, but has a broader application across the electronic, physical, and personnel security domains. The set also provides a much more useful basis for use in management, requirements engineering, systems engineering, and system design methodologies.

On the Validation of System Dynamics ModelsConceptual system dynamics (SD) modelling is frequently justified on the (intangible) basis that it facilitates our understanding of complex dynamic problems, those involving feedback and delay. Critical threats to building understanding arise when hypothesised cause-and-effect relationships become the bases of our models, which then evolve to become quantified representations upon which we rely. In SD, validation is taken to mean building confidence (in the model) whereas in systems engineering (SE), validation is formally conducted against specified requirements. An SE approach to building SD models would demand that each model be built on the basis of a defined ser of modelling requirements and validated against those requirements. Arguably, this would demonstrate the validity of the model and its utility as a necessary and sufficient representation of the real world. This work addresses the challenges arising in the validation of SD models and how an SE approach to validation could improve the extant SD modelling methodology.

The Need to Address Rework in Project Scope ManagementFor projects to be successful, project managers must manage effectively the risks to delivering on time, within budget, and within scope. While there is a large body of knowledge relating to project risk management, one area that is not widely recognised is that of the impact of rework on project performance and outcomes. Rework is generally considered to be an inevitable consequence of making errors during work that can be monitored and controlled as a routine part of day-to-day project management. This research applies systems dynamics modelling to obtain insights into the impact of error rate (and consequent rework) on project scope, particularly when project requirements are not firmly established at the outset. The insights gained indicate that rework contributes substantially to project failure and is deserving of greater attention than it often receives. A better understanding of the effect of rework could be valuable if used to inform not only routine project management and quality assurance activities but also governance activities relating to investment approvals and project or program performance reviews.


» Underwater Communications

SEIT AcademicsDr Mike Ryan Prof Elanor Huntington Prof Michael Frater Mr Craig Benson Dr Mark Reed Dr Andrew Lambert Dr Frank Jiang Dr Robin Dunbar

SEIT Postgraduate StudentsMr Rony Rahman Mr Qichao Zhou Mr Md Jahangir Alam Mr Kowshik Paul Mr Sunit Gosh Mr Md Shamim Anower

SEIT Research StaffDr Aleksandar Davidovic

Research DescriptionThe oceans play a vital role in life on Earth. Not only do they cover over 70% of the Earth‘s surface, but they play a vital role in regulating our climate, providing food and sit over substantial natural resources. The oceans are however relatively unexplored, and poorly understood. Technology is starting to change this lack of knowledge. Sensors capable of monitoring conditions for extended periods of time are being placed in ever greater number and remotely operated or autonomous vehicles can survey hostile environments. One of the major bottlenecks in collecting this data in near real time is underwater communication.

Sending data from submerved sensors and vessels cannot normally be done by radio communications as is done in most other domains. Radio waves propagate only very short distances under water, and the higher the frequency, the shorter the communication range. Alternates to radio waves are light, sound and cables. Cables can include fibre-optics, and can therefore offer very high data rates, as well as potentially providing power to a sensor or submerged vehicle. Such tethers to stationary nodes need expensive connectors, and must be terminated to an interface node, such as a surface buoy. Surface buoys being problems of their own in terms of maintenance cost, potential obstructions to shipping traffic, and susceptability to damage from extreme weather. Cables connecting to vehicles are normally known as umbilicals or tethers, and complicate vehicle operations as well as requiring specialised ships on the surface. Wireless solutions such as light or sound are therefore appealing.

Light can be used to obtain relatively high data rates through reasonable distances. The biggest drawback is that the communication distance if light underwater is dramaticallly affected by turbidity. Turbid waters, such as Singapore harbour, have shown communication ranges as short as a few meters[chitre]. Acoustic signals have long been used for underwater commuication. Acoustic signals can travel long distances, and are relatively unaffected by turbidity and changes in the water composition, such as temperature, salinity and pressure. The difficulties faced in using underwater acoustic signals for commuication are: a slow signal propagation speed of around 1500m/s, the relatively low frequencies, and hence signal bandwidths - which cause low data rates, strong multi-path and doppler effects, and spreading losses, potentially frustrating channel reuse in cellular or similar communication concepts.

The underwater communications research group has been tackling a range of these issues, as well as considering wider networking and communication challenges in the underwater domain.

A High Frequency ModemIn 2011 we enhanced tha maturity of our FPGA based acoustic modem assembly. This modem is novel in that it is designed to operate at a carrier frequency that is more than an order of magnitude higher than conventional acoustic modems. We implemented modulation schemes with raw data rates up to 160 kbps using QPSK. This data rate can be readily expanded by increasing the symbol rate (signal bandwidth).

The software based modem incorporates a unique pulse shaping filter in the modulator and demodulator. This filter reduces intersymbol interference, using a root raised cosine at the transmitter and receier. The filter is implemented as a FIR fiter, but instead of multiplying the tapped signal by each filter weight, the weighted tap is calculated by right-shifting a binary version of the signal. At each tap the weighted output is calculated as the sum of two right-shofted versions of the signal. This a tap of, say 0.78 is approximated as 1/2 + 1/4 = 0.75. The inverse powers of two being easily obtained by bit-shifting. A long FIR filter with response suitably close to the ideal can in this way obtained without incurring the high cost of multiplication in an FPGA.


The High Frequency Underwater Acoustic ChannelWe took measurements to improve the understanding of the high-frequency underwater acoustic channel. Such understanding is essential to develop suitable modulation and equalisation techniques for mature communication systems. It appears that the high-frequency channel suffers less from multi-path than conventional underwater acoustic commnunication. We plan to further develop our understanding of the high-frequency channel by development of a detailed channel model in 2012.

Network Routing Protocols for Underwater Acoustic NetworksAssuming that high data rates, equal to those above, on underwater acoustic communication links can be achieved we have examined how existing mobile ad-hoc network routing protocols would perform. This study has indicated two major problems. Firstly the data rates are still relatively low, so network congestion develops quite rapidly. Secondly, the slow propagation speed of acoustic signals means that communication packets are short relative to the link propagation delay. This frustrates the operation of a Medium Access Control (MAC) protocol. MACs that use a virtual carrier sense such as MACAW (RTS-CTS-DATA-ACK) handshaking from wifi networks waste most of the channel‘s time waiting for the handshaking signals to propagate. Pipelined MAC approaches such as PCAP[jason] can make better use of the channel, but transmission slot negotiation must be reserved well in advance of data transmission, so latency is high. Our network modelling uses a simple carrier sense multiple access regime. The carrier sense does nothing more than ensuring that an existing receive operation is not terminated by a packet being transmitted. Existing transmission will still prevent reception of new packets arriving at the transceiver while it is in transmit mode. Additionally, multiple packets may be received at the same time, again resulting in lost packets. Therefore some arriving packets will be dropped, the loss rate being a strong function of the network congestion.

Given that packet loss is so dependent on congestion, we have developed a protocol that avoids unnecessary transmissions. Control packets are kept short, and route maintenance operations are minimised. We also use a MAC that does not explicitly acknowledge receipt of messages on each link. This technique produces superior results to existing protocols in simulations. The improvement is explainable in terms of the reduced network congestions, which directly results from the ‚lightweight‘ routing and MAC protocols.

Frequency Re-use in Underwater Acoustic NetworksHigh Data Rates in a many user commuication network requires channel reuse. If the channel cannot be reused then the data rate per user will decline as the number of users in the network increases. Channel reuse is normally facilitated by a signal that decays with some exponent of range. In free space the attenuation would be proportional to range squared (r2) and close to the ground the two-ray ground model results in attenuation that is proportional to r4. Underwater acoustic communication channels do not show such strong decay, with practical spreading in underwater links assumed to be r1.5. At high frequencies the absorption on an underwater acoustic link is very high. This is often cited as a reason why underwater acoustic communications must use low frequencies. However if links are kept to short ranges, then the absorption on each link can be tolerated, and the same absorption could be used to reduce intereference from more distant nodes in a network. Part of our work with the high frequency modem is to also demonstrate that an underwater acoustic channel can be reused many times across a network, and that the main provider of isolatioon is absorption rather than spreading. In 2011 we conducted trials to verify that this approach results in observable improvement in network Signal-to-Intereference ratios at higher frequencies.

Improving signal-to-noise ratio and resolution of cross-correlation function using large bandwidth ambient noiseThe Green’s function of the channel between two points can be extracted from the cross-correlation between recorded ambient noise fields at those points. The SNR and resolution of the cross-correlation function is related to the emergence rate of the Green’s function, which depends on the number of coherent wave fronts extracted from the cross-correlation of noise fields. In a given environment a greater quantity of coherent signals can be obtained through longer observations, more observation points, or collection of a broader bandwidth. Long time averaging has been demonstrated, but requires that the channel be stationary over the averaging time. Hydrophone arrays are commonly used, but result in increased cost and complexity. In this research it is shown experimentally that instead of using an array of hydrophones or recording noises for long time, SNR and resolution of the correlation function can be improved by the use of the large bandwidth (48kHz) noise fields recorded at two sensors. The effect of power equalization on the ocean noise field is also demonstrated, which significantly improves the resolution of the cross-correlation function. This work shows applicability to passive depth measurement as well as signal source location.


Localization in Underwater Sensor NetworksLocalization has received considerable attention because many wireless sensor network applications require accurate knowledge of the locations of the sensors in the network. The two main localization techniques are distance measurement and angle-of-arrival measurement. The former technique suffers from flip ambiguity due to either the presence of insufficient reference points or uncertainties in the inter-nodal distance measurements in a triangular network structure. A recently proposed quadrilateral structure (an extended complex version of a trilateration structure) can resolve flip ambiguity of a node in dense deployments under restricted orientations for anchors, however, the technique leaves open issues to consider imprecise inter-nodal distances between all pairs of nodes as complexity increases to address the computations. Moreover, both the structures (triangular and quadrilateral) completely fail to resolve flip ambiguity in sparse node deployments as sufficient nodes are not available in order to determine the signs in calculated angles. On the other hand, AOA can provide the sign of the angles but requires expensive hardware calibration to provide a high-level of accuracy in the measured angles. Therefore, there is a need of a localization technique that is cheaper, less complex, and robust by considering measurement uncertainties between all pair of nodes and more importantly, involves fewer reference nodes.

The primary contributions of our work include a hybrid technique that uses low-accuracy (cheap) AOA measurements along with erroneous distance measurements between each pair of nodes in a much simpler triangular network that corresponds to a sparse deployment. In our initial phase we develop mathematical models involving only two reference nodes that are able to resolve flip ambiguity a unknown node with a high probability of success even with an RMS error as high as 150 in the line-of-bearing estimate, which avoids the need for calibration in many practical situations. In later phases, we modelled our hybrid localization technique to accommodate imprecise inter-nodal measurements between all pairs of nodes. In the final phase, we extend our localization technique estimate network layout for extremely sparse node deployments by eliminating flip ambiguity to facilitate efficient routing. Our hybrid approach for resolution of flip ambiguity is useful, not only to develop lower-complexity localization techniques, but also for many lower-layer network functionalities such as geographic routing, topology control, coverage and tracking, and controlled mobility when a large number of these nodes have to be deployed and minimal anchor dependency are required.

Sensing Network Scale and DimensionalityIn a large-scale wireless sensor network, it is often desirable to count the number of nodes in the network, or the number of nodes that are within communications range of a particular node. To date techniques employed to estimate the number have been based on some aspect of the communications protocol(s) in use. In this paper, we propose an estimation technique based on cross-correlation of random signals, in which the ratio of the mean of the cross-correlation function to its standard deviation determines the number of nodes. This proposed technique addresses a number of practical issues in a digital receiver, including fractional-sample delays, internal noise etc. An error analysis is provided that demonstrates the superior performance of this technique to protocol-based methods.

The estimation of the number of nodes using cross-correlation depends on the dimensionality of the nodes. So it will be better if we could estimate the dimensionality first. The estimation of the dimensionality of the nodes measures whether the nodes are oriented in 1D, 2D or 3D. The dimensionality of the nodes would also be helpful in obtaining additional information about the network e.g. localization of the nodes, AOA estimation etc. Researches are going on regarding the dimensionality of communication networks. Most researches on dimensionality are for the network architecture before deployment of the nodes. But the dimensionality of a deployed unknown network is almost new research area. In my knowledge, one protocol-based technique has been proposed for the dimensionality estimation in a communication network. It has already been mentioned that use of protocol is inefficient in some environment like underwater, underground, etc. In this work, similar cross-correlation technique to estimate the number of nodes has been used to estimate the dimensionality of a communication network after deployment. The process will be concurrent with the number of nodes estimation. Thus the proposed cross-correlation technique to estimate the number of nodes with their dimensionality will be interesting in the field of wireless communication network like WSN, RFID, etc.


» Unmanned VehiclesSEIT AcademicsDr Matt Garratt A/Prof Hemanshu Pota Dr Sreenatha Anavatti Dr Andrew LambertDr Tapabrata Ray

SEIT Postgraduate StudentsMr Tushar RoyMr James TaylorMr Mohsen TehraniMr Sobers FrancisMr Osama HassanMr Khirul Alam

SEIT Research StaffMr Anthony PeeblesDr Mahendra SamalDr Hamid Teimoori

Other Collaborators


A/Prof Jinling Wang

Research DescriptionThe unmanned vehicles research group has been working with both fixed and rotary wing unmanned aircraft for over a decade. In the past two years, work has also begun with unmanned ground vehicles and unmanned underwater vehicles. Expertise extends from studies of the aerodynamics of flapping wings and micro air vehicles, through robust autopilots, to the practicalities and challenges of rotary wing operations from maritime platforms. The research carried out during 2011 is explained in the following paragraphs.

High-Bandwidth Control of an Unmanned Helicopter

This Australian Research Council (ARC) funded project aims to develop high bandwidth control methods and advanced dynamic modelling for Rotorcraft Unmanned Aerial Vehicles (RUAVs).

This will enable new roles such as the precision landing of RUAVs to the moving deck of a ship in rough seas. During the past twelve months, we have developed a Model Predictive Control (MPC) based flight control system for the Vario XLC helicopter. MPC controllers are model based controllers which explicitly use the predictive model of the system to compute the future control moves. The MPC controller architecture replaces the widely used inner outer-loop controller structure. We have also proposed an analytical method to calculate off-diagonal terms of Q-matrix used the cost function for better tracking. A linear state space reduced order model for longitudinal and lateral dynamics of the helicopter is used for controller design. We have enhanced the MPC performance by augmenting the helicopter model with servo dynamics during the prediction phase. The inclusion of servo dynamics and time delay yields a smoother control response and we now have a control system which can tolerate a delay of more than 80milliseconds whilst maintaining superior performance.

The other major contribution of the past year has been a hierarchical inner-outer loop-based scheme for control in the presence of servo and delay constraints. The inner-loop (attitude controller) employs an inverse optimal control strategy, which circumvents the tedious task of numerically solving an online Hamilton-Jacobi-Bellman (HJB) equation to obtain the optimal controller. The designed controller is optimal with respect to a meaningful objective function which considers penalties for control input, angular position and angular velocity. The outer loop makes use of the backstepping technique, which guarantees the asymptotic stability and tracking performance in three channels (lateral, longitudinal, vertical) simultaneously. Moreover, in order to compensate the time delay in the control loop, the position controller gains are tuned systematically to accommodate the time delay. This new method takes advantages of both inverse optimal control strategies and backstepping which makes it simple, easy to tune and implement in flight tests. To investigate the optimality of the proposed attitude controller, its performance has been compared with another controller designed using feedback-linearisation (FBL) method. Our simulations show that, in large attitude or angular velocity errors, our controller achieves global stability with less control effort than the one designed with the FBL method.

Figure 1: Vario XLC Gas turbine helicopter used for experiments into High-Bandwidth Control


Concept Air Vehicle HoverThe objective of this Defence Science and Technology Organisation (DSTO) funded work is to develop a reliable system for sensing and controlling the hover of a Micro Air Vehicle (MAV). The work will be suited to both rotary wing and flapping wing implementations. The system would require only visual and inertial sensing, breaking the reliance on technologies such as GPS which can be selectively disabled or jammed and which may be unavailable indoors and in cluttered environments. Range measuring technologies are required for control of height in hover but state-of-the-art options for sensing height such as laser range-finders or radar are simply impractical for MAVs owing to the physical barriers to miniaturisation that exist. Additional advantages of visual guidance are that it is passive, small and low cost.

The problem of developing a reliable system for sensing and controlling the hover of a Micro Air Vehicle (MAV) using visual snapshots is considered. A new algorithm has been developed that uses a stored image of the ground, a snapshot taken of the ground directly under the MAV, as a visual anchor point. The absolute translation of the aircraft and its velocity are then calculated by comparing the subsequent frames with the stored image and fed into the position controller.

A Collaborative 3D Ranging and Mapping for Satellite Remote SensingThis project aims to demonstrate a miniature payload system for mapping of terrain using multiple imaging platforms. By geo-referencing imagery using a single sensor, 2D maps can be constructed. However with 2 or more spatially separated sensors, image disparity (stereo vision) can be used to determine the range and 3D layout of terrain. The eventual aim would be to use a cooperating swarm of micro-satellites to build 3D terrain databases in real-time. With real-time processing being our eventual goal, a snapshot of dynamic environments such as beaches, battlefields, urban landscapes etc can be mapped. 3D data is valuable for many applications such as visualisation of buildings, construction, monitoring of erosion, surveying etc. The 3D products can be used as ground truth provider for large scale satellite data processing. They can also be used alone in disaster management on a local scale where manned aircraft cannot access. For example they can serve as a real time assistant in fire control by identifying fuel distribution (such as tree heights and density), and magnitude of damage.

Our aim in this project is to demonstrate 3D mapping using an unmanned aerial vehicle (UAV) flying with spatially separated sensors. In future work, this would be expanded to multiple UAVs flying in formation. The basic concept will be to fly over terrain using at least 2 sensors with video logging capability. Using accurate time stamping and accurate position and orientation data from GPS/INS, the logged image streams will be able to be combined and compared to determine 3D position for each pixel image. Image registration techniques will be applied to overlapping images so that the pixel disparity between corresponding features from both images can be used to determine range in the images.

For this work, we have developed a system for storing uncompressed images to a compact flash card media for later post-processing. Image data is collected from large format CMOS sensors, and parsed by a Field Programmable Gate Array (FPGA) system. Whilst our eventual aim is for real-time evaluation, work for this project will be done using post-processing. The FPGA based image processing engines are existing units developed at UNSW Canberra with added high speed LVDS links for transmission of image data to the logging system. The logging system comprises a secondary FPGA which assembles the imagery, synchronisation data and telemetry into a format suitable for high-speed storage onto CompactFlash. The video logger stores high-speed uncompressed digital video at 50 Mpixels/sec. The ancillary data includes timestamps and live telemetry such as the helicopter position, speed and orientation.

Figure 2: An External FPGA based imaging system incorporating megapixel CMOS image sensor provides high speed LVDS transmission of data and telemetry to the Video Logger, also FPGA based, for storage on the high throughput non-volatile CompactFlash card.


Obstcale Avoidance for Autonomous Vehicles:Our research aims to overcome some of the significant challenges facing autonomous navigation in cluttered environments which limits numerous applications including flight of micro air vehicles through urban landscapes, automated mining exploration, digital mapping, environmental monitoring, military surveillance and reconnaissance, search and rescue missions, underwater applications and industrial automation. Path planning for an autonomous ground vehicle (AGV) is a challenging task due to incomplete information about the surroundings and is particularly hard in a dynamic environment. For successful and complete path planning in cluttered environment, the AGV needs to replan its path quickly in such a way to avoid any obstacles if necessary, until it completes the assigned task.

Efficient D* lite algorithm has been proposed by using the Fibonacci heap data structure as its priority queue and it performs well in the dynamically varying environment by reducing the total computational time for replanning the path. The Efficient D* lite algorithm has been implemented in the onboard Pioneer 3DX mobile robot. The various experiments have been done in the dynamic environment and the results are compared with the existing algorithms. A 3D range camera, which provides a range measurement for every pixel in the image, is used along with sonar sensors to obtain the behaviour of the obstacles. The range camera is also used to get the depth information of the obstacles and to determine the 3D geometry of the obstacles. These data from the sensors are used effectively to predict the trajectory of the dynamic obstacles from their previous positions.

Smart Guidance and Control of Autonomous Underwater Vehicle (AUV)Autonomous Underwater Vehicles (AUV) have gained importance over the years as specialized tools for performing various underwater missions in military and civilian operations. The autonomous control of underwater vehicles poses serious challenges due to the AUVs’ dynamics. AUVs dynamics are highly nonlinear and time varying and the hydrodynamic coefficients of vehicles are difficult to estimate accurately because of the variations of these coefficients with different navigation conditions and external disturbances. This study presents a system identification of AUV dynamics as a black box which has an input-output relationship instead of using the mathematical model with hydrodynamic parameters to obtain the dynamic model to overcome the uncertaininaty, nonlinearity and the difficulties of modelling the AUVs.

We have developed AUV dynamic model identification based upon fuzzy and hybrid nural fuzzy techniques with online adaptive and learning algorithm. The modelling techniques have been validated using simulated data in the presence of noise and disturbances.

Moreover, we have designed and developed an on-line system identification using adaptive neural fuzzy network (ANFN) based upon the error between the identified model and the actual output. The proposed ANFN model is based on a functional link neural network (FLNN) as the consequent part of the fuzzy rules. In this study, the functional expansion block comprises of a subset of orthogonal polynomials bases function. The FLNN has been inserted to the consequent part of the fuzzy rules. The local properties of the consequent part in the ANFN model enable a nonlinear combination of input variables to be approximated more effectively. The FLNN is a single-layer neural structure capable of forming arbitrarily complex decision regions by generating nonlinear decision boundaries with nonlinear functional expansion.

In addition, we have applied an online parameter tuning technique for the fuzzy model and ANFN model. The learning process involves determining the minimum of a given cost function. The gradient of the cost function is computed and the parameters are adjusted with the negative gradient. Back Propagation technique is used for online tuning of the fuzzy model.

Figure 3: Pioneer 3DX mobile robots used to tyest obstacle avoidance using a 3D range camera.


On the controller side, indirect adaptive fuzzy controller and Adaptive Neural Fuzzy Network (ANFN) Controller for forward pitch and yaw motion controllers are developed. We used triangular membership function in the fuzzy controllers. We have used Back Propagation technique for online tuning of the fuzzy controller. We have derived the tuning equations for triangular membership function. This adaptive fuzzy has been tested and validated with normal operating condition and with existing of noisy sensor data and applying some disturbance and parameter variations into the model.

We have proposed an automatic model generating technique comprising a structure learning phase and a parameter learning phase. The only information required for generating the system is the input -output data. It means that there is no need for any prior knowledge of the physical relationship inside the system and it offers an “automatic generating black box’ modeling tool. Structure learning is based on the entropy measure used to determine whether a new rule for fuzzy system should be added to satisfy the fuzzy partitioning of input variables. Parameter learning is based on supervised learning algorithms. The back-propagation algorithm minimizes a given cost function. Initially, No rules and memberships exist and there are no nodes in the network except the input–output nodes. The memberships, rules and nodes are created automatically as learning proceeds, upon the reception of online incoming training data in the structure and parameter learning processes. We have applied this technique to generate automatically fuzzy model, fuzzy controller, ANFN model and ANFN controller.

We have finished the design and setting up the electrical and electronic system of the AUV that needs to consider the functionality and tasks required of it. In addition, The electronics system consists of a PC/104 single-board industrial type computer with IO module that which contain digital I/O, analogue I/O and PWM channels. For this study, a low-cost IMU is used together with other relatively low-cost sensors such as magnetometer and water pressure sensor for depth measurement. The following figure shows the AUV in different conditions.

All the electrical and electronic system components already have been installed in the vehicle. We have tested the functionality and all electrical and electronic system and the bouncy of the vehicle in the swimming pool. We are going to implement and test all the modeling and control techniques which has been mentioned above in real time on AUV.


» Virtual Environments & Simulation

SEIT AcademicsDr Michael BarlowProf. Hussein AbbassDr Sameer AlamMr. Mike FordDr Ed LewisDr Chris LokanDr Kathryn MerrickDr Ruhul SarkerDr Kamran ShafiDr Rob Stocker

SEIT Postgraduate StudentsMr. Hock Chuan LimMs. Erandi Lakshika Hene KankanamgeMr. Umran AbdullaMr. Suranjith De SilvaMr. Joe Winter

Other Collaborators


Dr Ning Gu

SimCentric Technologies

Dr Adam Easton

Research DescriptionVirtual Environments (virtual reality) and simulation are technologies undertaking increasing roles in the areas of education, industry, defence, government, and entertainment. As tools for a military commander to quantify whether a Course Of Action is feasible, a means for government to assess the impact of a change in health care policy, or a physics teacher to convey and illustrate a dry mathematical formula - taken together simulation and VEs offer the ability to model any scenario or problem and see that situation “play out” in immersive 3D.

Work in VEs and simulation within SEIT proceeds along several major axes or themes – the technology of multi-agent systems; the application of commercial games for training, teaching, and decision-support; the application of high fidelity simulations to answer questions about change in policy or introduction of technology in a complex system (e.g., air traffic management); the value of and task-dependent choice of level of immersion; visualisation techniques for rich and complex data; the analysis of strategy and evolutionary games; and models of human decision-making, leadership morals, ethics, and teamwork. All are viewed with a complex systems lens; interconnecting work in this area with that in other groups such as Transportation Modelling and Automation, Computational Intelligence, Modelling & Cognition, Machine Learning & Developmental Robotics, and Social Networks. Indeed, a number of projects straddle more than a single group and may be found listed under one of the groups previously mentioned.

Spatio-Temporal Dynamics of Groups in Standing Conversations: Complexity through Local Interactions High fidelity virtual environments are being used extensively in various domains ranging from the military, social sciences, and artificial life, to the entertainment industry and city/building planning. The applications include such diverse purposes as training, education, planning and emergency management. The simulation industry has long recognised the importance of incorporating the richness of real life action and interaction into the characters in the virtual environments in order to improve the believability of the simulations. Rule based Multi Agent Systems facilitate the representation of collective behaviour as an emergent property of the interactions happening between simple rules codified into the individual agents. Such an approach has the desirable characteristic of creating sophisticated group-level behaviours while keeping the computational cost low. This project is motivated by the boid-rules introduced to synthesize the complexity of a flock of bird-like objects and extends the approach into the social simulations of conversation group dynamics. Four conceptual rules- namely- “Keep Personal Distance”, “Keep Centre of the Conversation”, “Keep Visibility” and “Keep Distance to the Nearest Neighbours” synthesize position and orientation dynamics of people taking part in a standing conversation – for instance a cocktail party – particularly when new participants join the conversation and existing participants leave the conversation. Different rule configurations (at varying number of rules and combination mechanism) were evaluated for the visual fidelity by human evaluators. The results of the evaluation suggest that the interactions between the rules are capable of closely recreating positional and orientation dynamics of real world standing conversation groups. The goal of this ongoing work is to derive the relationship between rule-complexity and visual fidelity of boid-like Multi Agent Systems. The work is also progressing into the other problem domains such as simulation of sheepdog herding behaviours.

Figure 1: The relationship between number of rules and scores (0 being not realistic at all and 9 being as realistic as a real life scenario) provided by human evaluators.


Generative Social SimulationA generative social simulation project to investigate the interplay of ethical trust and social moral norms, (specifically in the areas of simulated agent moral cognition, increased duration of agent interaction and feedback from the environment) was initiated as part of a PhD research program. This project addresses two key aspects namely the computational modelling of ethical processes and the social simulation of agents and network effects using a priming behaviour framework of animal behaviour research.

Simulations and experiments are closely linked to the generative philosophy. The simulation and generative experiment logic is introduced and can be compared to the traditional logic of simulation as a research method (See Figure 2. and Figure 3).

The social simulation applied a modified generative linked experimentation approach wherein the experiments are linked in the form where the outcomes of the previous experiments were used as design inputs to aid in the formulation of the next experiment. A total of five experiments were conducted. These five experiments covered investigations of:

– Agent attributes (such as values for ethical trust and ethical dispositions)

– Extended agent parameters/attributes;

– Social structures (

– Extended network parameters

– Environment feedback (selected mode)

The key findings are trust signals influence agents’ interactions and ethical trust can primes moral behaviours and hence impact the spread of moral norms in social agent communities. The addition of social structure and additional moral cognitive elements, however, mediates and reduce the effects of trusts signals. The further addition of feedback from the environment serves to increase the impact of network structure. From these findings, three observations are drawn namely:

– Agent-based, network-based and generative simulation are useful for modelling and investigating complex social processes

– Relationships in social processes and social structure will require careful investigation to derive meaningful results;

– Elements of agent attributes (such as ethical trust, moral cognition, ethical dispositions and network structures) are important for the study on the spread of social moral norms

– In 2011, this project facilitated the publication of a journal paper and a self-contained chapter for Book on Advances in Intelligent Digital Ecosystems.

Model Simulated Data

Target (Visible Social processes)

Collected Data

Simulation run

Data Gathering

Abstraction Similarity

Figure 2: Logic of simulation modelling as a research method

Model Generated Data

Target (Social processes)

Proxy Data

Simulation, Generative experiments

Data Gathering

Abstraction Similarity

Figure 3: Logic of simulation and generative experiment


Computational Creativity and Procedural Content Generation in Computer GamesWith rapid growth in both production costs and player populations over the last decade, the computer games industry is facing new scalability challenges in game design and content generation. The application of computers to these tasks – called procedural content generation – has the potential to reduce the time, cost and labour required to produce games. A range of generative algorithms have so far been proposed for procedural content generation. However, automated game design requires not only the ability to generate content, but also the ability to judge and ensure the novelty, quality and cultural value of generated content. This includes factors such as the surprise-value of generated content as well as the usefulness of content in the context of a particular game design. Studies of human designers have identified that the ability to generate artefacts that are novel, surprising, useful and valuable are facets of the human cognitive capacity for creativity. This suggests that computational models of creativity may be an important consideration for developing tools that can aid in or automate design processes. However such cognitive models have not yet been widely considered for use in procedural content generation for games. This project has developed a framework for procedural content generation systems that use computational models of creativity as a part of the generative process. A software system has been implemented that combines the generative shape grammar formalism with a model of creativity based on the Wundt curve to select new designs that are similar-yet-different to existing human designs. The approach aims to capture the usefulness and value of existing designs while introducing novel and surprising variations. The system incorporates a metric that permits generated designs to be evaluated in terms of both their similarity to high quality human designs and their creative novelty.

Simulation and Analysis of the Australian Aiport NetworkAs for all means of transportation, the relationship between origin and destination results in a complex network of routes, which can then be complemented with information associated with the routes themselves, for instance, frequency, traffic load and distance. The theory of complex networks provides a framework for simulating and investigating the dynamics on the resulting network structure.

In this work, we [Hossain, Alam, and Abbass] investigated the structure and robustness of the Australian Airport Network (AAN) by simulating it as a complex network. This study investigates the indices of degree distribution, characteristics path length, clustering coefficient and centrality measure as well as the correlation between them. Complex network simulation and analysis of the ANN indicates that the resulting network has a cumulative degree distribution described by an exponential function and displays small-world network properties.

Figure 4: A procedurally generated game level (left) and an actual game level (right) from a popular game which served as the template for the shape/level grammar.

Figure 5: Cumulative degree distribution in the Australian air transport network.


A Simulation and evaluation environment for Aircraft User Preferred Routes

Future air navigation will be based on 4-D Trajectory Management which will be translated from a User Preferred Routes (UPR), which are the routes with the best business outcome from the airspace user’s perspective. In this work we [Pham, Alam, Lokan & Hussein] designed and developed a simulation environment to generate UPRs. The environment can evaluate UPR concept for different UPR algorithms in different flight and weather scenarios. The impacts on environment, delay, and safety are analysed. It’s expected to find the best UPR algorithms for specific routing circumstances as well as to provide insight understanding of UPR routes.

The simulation of a 4-D route for an aircraft, which is given aircraft performance, a 2-D (latitude, longitude) route, and altitude profile in a weather environment, includes the following three basic simulation models:

– Climb to Top of Climb

– Top of Climb to Top of Descent (Cruise Phase)

– Top of Descent to Touch Down

This work provides the framework for fundamental simulation and evaluation of UPR segments and trade-off analysis of different UPR routes.

Simulation and Operations ResearchSimulation is an important research area in Operations Research. At UNSW Canberra, there is a strong research team who conduct applied research using simulation in both defence and non-defence domains. Two of such examples are briefly reported here.

Supply Chain Simulation: In the last decade, supply chain operations have received tremendous attention in manufacturing and business sectors due to an increasingly challenging marketplace. The research team develops a multi-agent simulation model for a manufacturing supply chain operation. The model is capable of handling complex networks with many tiers, each tier with many business units and complex interactions among them. The team has discussed the multi-agent architecture and run simulation for analysing the operational aspects. This will allow companies to quantify different interacting parameters in the supply chain and help support to make improvement in operations.

Simulation for Spare Planning: In practice, maintenance and spare parts inventory policies are treated separately or sequentially. To ensure availability of spare parts for a production system use, when necessary, there is always a tendency to overstock them. Excess inventory involves substantial working capital. The stock level of spare parts is dependent on the maintenance policy. Therefore, maintenance programs should be designed to reduce both maintenance and inventory related costs. In this research, a manufacturing system is considered with stochastic item failure, replacement and order lead times of statistically identical items. The development of mathematical model for such a system is extremely difficult. A simulation model is therefore developed for the system operating with block replacement and continuous review inventory policy. The response of the system was studied for a number of case problems. The study clearly shows that the jointly optimized policy produces better results than that of the combination of separately or sequentially optimized policies.

Figure 6: UPR Simulation Model

S1 M1 W1 R1

S2 M2 W2

Market

R2

S3 M3 W3 R3

Sn Mm Wk Rp

Figure 7: A Supply Chain with multiple entities in each stage.


The School of Engineering and Information Technology occupies five adjacent buildings at UNSW Canberra, located at the Australian Defence Force Academy.

Building 15 houses most of the Computer Science and Information Systems’ components of the School. It also contains:

– Several general-purpose, high-quality Computer Laboratories

– Image Coding Laboratory

– Computer Network Laboratory

– Studio, with Teleconferencing Facilities

– Cognitive Engineering Laboratory

Building 16 is a four level building containing some 1800 m2 of office and laboratory accommodation and houses most of the Electrical Engineering components of the School. It also contains two general purpose teaching laboratories, along with the following specialist laboratories used for both teaching and research:

– Microwave Laboratory and Anechoic Chamber

– Signal Processing Systems Laboratory

– Materials Processing Laboratory with Class 100 Clean Room

– Quantum and Laser Laboratories

– Electrical Machines and Power Electronics Laboratory

– Final-year project Laboratory

– Control Laboratory

– Robotics Laboratory

– Communication Laboratory

– VESL Laboratory

Building 16 also has an antenna range on its Eastern Roof, which can be controlled from within the Microwave Laboratory. Above the Signal Processing Systems Laboratory is a small, optical observatory that is used for teaching and research in restoration of atmospherically degraded images.

School’s teaching and research activities are supported by an Electronics Workshop (which has associated with it an RF screened room and printed circuit board facility), a Mechanical Workshop, (complete with carpentry shop, plating room, welding bay, and paint shop) and a components and raw materials store.

Building 17 is the John Baird Building, which houses the School’s Administration Group and most of the Mechanical and Aerospace Engineering components of the school. It also contains a meeting room, a computer room and the laboratories listed below.

– Non destructive Inspection (NDI) Laboratory

– Optics Laboratory

– Aviation Safety Studio

– Flight Simulator Laboratory

Research Facilities

Figure 1. Traffic Management and Simulation laboratory


– Materials and Mechanical Testing Facility

– Micro-nano Photonics Laboratory

– Autonomous Vehicles Laboratory

– Advanced Composites Laboratory

Building 18 contains a workshop and a design room that is set up for computer aided design and manufacturing work for undergraduate thesis work and postgraduate research projects. It also contains:

– Acoustics and Vibrations Laboratory

– Anechoic Chamber

– Fluids Laboratory

– Thermodynamics and Vehicles Laboratory

– Model Aircraft Laboratory

– Vibrations Laboratory

– Supersonic Wind Tunnel and Shock Tube laboratory

Building 20 houses most of Civil Engineering components of the School and also contains:

– Aquatic Systems Test Tank

– Hypersonics Laboratory

– Fluidic Thrust Control Laboratory

– Geotechnical Teaching Laboratory

– Microscope and Balance Room

– Temperature and Humidity Controlled Environmental Rooms

– Concrete, Soils and Bitumen Laboratory

– Fog Room

– Structural Testing Soils, Concrete and Steel Laboratory

– Hydraulics and Environmental Engineering Laboratory

– Geotechnical Engineering Laboratory

– Mechanics of Solids and Material Testing Laboratory

SEIT also has a number of mechanical workshop facilities with modern facilities for the design, manufacture and maintenance of equipment and experiments for undergraduate project work and postgraduate research.

Building 21 The Microfluidics Laboratory houses a range of equipment for the manufacture and study of flows in micro-fluidic devices and analytical instruments for measurement of physical properties of fluids. Micro-end milling is the main manufacturing method used for the manufacturing methods in the undergraduate student workshop enabling undergraduate students to gain an insight into the micro/nano technology area. Two fume cupboards are available for chemistry based experiments with facilities for the storage of flammable and corrosive chemicals.

Building 32 houses the School’s Traffic Management and Simulation Laboratory, located in Lecture Theatre North, (SR 101).

Figure 3. Autoclave

Figure 2. Test Section of Shock Tube


Figure 4. Cognitive Engineering Laboratory Figure 5. Hypersonic Shock Tunnel

Figure 6. Fixed Wing UAV

Figure 7. Telescope


Figure 10. Shimadzu universal testing machine

Figure 8. Yamaha UAV in transit for flight testing

Figure 11. Laser Diagnostics Laboratory

Figure 9. Adaptive optics


2011 SEIT Academics

Prof Elanor Huntington Head of School

A/Prof Andrew Neely Deputy Head of School

(Technical Support)

Prof Hussein Abbass Professor

Mr Craig Benson Senior Lecturer

Dr Chris Lokan Deputy Head of School

(Administration)

Dr Safat Al-Deen Lecturer

Dr Lawrie Brown Senior Lecturer

A/Prof Ruhul Sarker Deputy Head of

School (Research)

Dr Sreenatha Anavatti Senior Lecturer

Ms Sue Burdekin Senior Lecturer

Dr Alan McLucas Deputy Head of

School (Teaching)

Dr Michael Barlow Senior Lecturer

Dr John Arnold Professor

Deputy Rector

Mr Martin Copeland Lecturer

Dr Daryl Essam Senior Lecturer


Dr C.T. (Rajah) Gnanendran

Senior Lecturer

A/Prof Charles Harb Associate Professor

Dr Xiuping Jia Senior Lecturer

Dr Haroldo Hattori Senior Lecturer

Ms Bronwyn L. Jones Associate Lecturer

A/Prof Harald Kleine Associate Professor

Dr Rik Heslehurst Senior Lecturer

A/Prof Obada Kayali Associate Professor

Dr Matt Garratt Senior Lecturer

Michael Frater Professor

Rector

Professor Jiankun Hu Professor

Dr Amar Khennane Senior Lecturer

Prof Joseph Lai Professor

Dr Andrew Lambert Senior Lecturer

Mr Alan Fien Senior Lecturer

Dr Jong-Leng Liow Senior Lecturer

A/Prof Robert Lo Associate Professor

Dr Edward Lewis Senior Lecturer

Dr Michael j Maher Senior Lecturer

Mr Raymond Lewis Senior Lecturer


Dr Abdun Nasser MahmoodLecturer

Dr Gregory Milford Senior Lecturer

Dr Sean O’Byrne Senior Lecturer

Dr Gary Millar Lecturer

A/Prof Valeri Ougrinovski

Associate Professor

Prof Ian Petersen Professor

Dr Robert Niven Senior Lecturer

A/Prof Mark Pickering Associate Professor

Prof Evgeny Morozov Professor

A/Prof Hemanshu Pota Associate Professor

Dr Kathryn Merrick Lecturer

Mr Heath Pratt Lecturer

Dr Tapabrata RaySenior Lecturer

Dr Mark C. ReedSenior Lecturer

Dr Michael Ryan Senior Lecturer

Dr Kamran Shafi Lecturer

Dr Krishna Shankar Senior Lecturer

Dr Warren Smith Senior Lecturer

Dr Murat Tahtali Senior Lecturer

Dr Tim TurnerSenior Lecturer


Dr John Young Senior Lecturer

Dr Sarah (Yixia) Zhang Senior Lecturer

Dr Weiping Zhu Senior Lecturer

Dr Kathryn WilsonSenior Lecturer

Mr Trevor Wheatley Lecturer

Mr Alan White Senior Lecturer

Mr Eric Wilson Senior Lecturer


Production:Editor: Dr Sreenatha Anavatti School of Engineering and Information Technology Design: Creative Media Unit

Cover image: Rotary UAV

Back cover image: Hypersonic Tunnel


Never Stand Still School of Engineering and Information Technology

Contact usIf you would like further information, please contact the Research Student Admissions Coordinator:A/Prof Mark PickeringTelephone: +61 2 6268 8238 Fax: +61 2 6268 8443 Email: [email protected] School of Engineering and Information Technology The University of New South Wales Canberra PO Box 7916 CANBERRA BC ACT 2610Cricos Provider Code: 00100G • CMU 13492

The School of Engineering and Information Technology is one of four Schools of the University of New South Wales located at the ADFA campus in Canberra. Research is a key focus for the School, and inspires our approach to teaching and other activities.


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“Once we accept our limits, we go beyond them” – Albert Einstein

Documents

SEIT Research Report 2011_Final