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Contents

Welcome Message 2

Timetable Day 1 4

Timetable Day 2 5

Poster Session Information 6

Keynote Presenters 7

Invited Research Associate Abstracts 8

Abstracts 10

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Welcome Message

On behalf of the School of Electrical, Electronic and Computer Engineering Annual Re-

search Conference 2012 (ARC 2012) Organising Committee, it is my great pleasure to

welcome you to the 14th Annual Research Conference at Newcastle University.

The School of Electrical, Electronic and Computer Engineering aims to provide a re-

search environment in which ambitious new and original ideas can flourish. This ideal

has led to the development of unique expertise in many fields, such as wireless com-

munications, sensors and devices for harsh environments, power electronics, drives and

machines and microelectronic system design. The Annual Research Conference provides

an excellent opportunity to come together, along with industrial representatives, to cel-

ebrate the annual achievements of the school and to share all of the research that is

successfully undertaken each year. It also creates an opportunity to meet people from

other research areas, exchange knowledge, discuss common research interests and develop

communication skills.

This year, a new website has been introduced to the conference, which allows online

registration, submission and reviewing to all take place online. The committee members

are delighted that the new website has facilitated the submission of papers and reviews to

an excellent standard, whilst making the process very simple and would like to thank the

School IT team and Graeme Coapes, the conference Web Manager, for their hard work.

The conference committee is also very pleased to welcome our conference sponsors

BAE Systems, Turbo Power Systems and the IET and look forward to their participation

in the conference throughout the two days. We would also like to express our gratitude

to our generous sponsors for helping to make this event possible. Contributions from our

sponsors have allowed the committee to bring more value and expertise to the conference

and for that we are very grateful.

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We would also like to take this opportunity to extend our personal thanks to the

Postgraduate Research Coordinator Mrs. Gill Webber, the Director of Postgraduate

Studies Dr. Alton Horsfall and the Head of School Prof. Bayan Sharif for their invaluable

help and support.

This years conference will involve over 100 technical presentations describing their

latest research and findings to over 150 attendees. This will cover a vast range of research

areas that are explored across every research group within the school that we are very

proud to present. We hope you enjoy the conference and take something of value away

from the two days.

With best wishes,

Karthik NagareddyCommittee ChairGraeme CoapesIT Co-ordinatorHua Khee ChanEvent Co-ordinator

Lucy MartinCommittee Vice-Chair

Anvar TukmanovIndustrial Liaison

Andrew WechslerStudent Liaison

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Timetable Day 1

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Timetable Day 2

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Poster Session Information

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Keynote Presenters

BAE Systems MarineRoom 2.21 & 2.22, Day 1, 9.30-10am

Russ MorganResilient Technology ManagerDr Russ Morgan has more than 25 years experience in Semiconductors, MEMS, Photonics,Sensor development and manufacture. With a PhD in Plasma Physics and Device fabri-cation he has published books and a substantial number of academic papers on plasmaprocessing and manufacture. He also has several patents in advanced materials, sensors,semiconductors and processing. In the last 15 years he has had senior key roles at PhilipsResearch Labs, Air Products, Applied Materials, BAE systems and INEX. He has beenan expert consultant for DSTO Australia, CSIRO Australia, AMD, INTEL (US), IBM,Radiation Watch and Nanoplas. He is currently the Resilient Technology Manager forBAE Systems Marine, where he advises on technology solutions for the next generationof submarines

Turbo Power SystemsRoom 2.21 & 2.22, Day 2, 1.10-1.50pm

The presentation will be focused on past, present and future products of Turbo PowerSystems. These are designed in Gateshead and London and manufactured in the UK.Turbo Power Systems manufactures high speed motors, drives, auxiliary power units forrail systems and power electronics for industrial cutting lasers in Gateshead and Heathrow.

Graeme ThompsonChief Engineer Power ElectronicsSince graduating from Newcastle University Graeme has more than 25 years experiencein Power Electronics design for the Rail, Aerospace and Industrial sectors.

Dr Robert BolamPrincipal EngineerRobert graduated with an EngD from Newcastle University. His current focus is drivesfor 300kW to 1MW high speed permanent magnet motors.

Nik StauntonSenior Design EngineerNik’s current focus is on grid linked and islanded inverters powered from high speed per-manent magnet generators attached direct to gas turbines. Nik is a current postgraduatestudent at Newcastle University.

Simon ONeillEngineering DirectorSimon is responsible for R&D operations of the Power Electronics Division and has abackground in RF engineering.

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Invited Research Associate Abstracts

Di!usion: il buono, il brutto, il cattivoSergei SimdyankinRoom 2.22, Day 1, Time 1.05pmDi!usion is a ubiquitous phenomenon, which can be both useful and detrimental. It is avitally important process, which governs kinetics of many microstructural changes duringthe preparation of materials for electronic devices. Detailed understanding of this processis instrumental in designing new generation devices under the constraint of continuedminiaturisation. This understanding can be significantly enhanced by using computermodelling. Process simulation is the primary stage in Technology Computer Aided Designtools, which are widely used in order to streamline device design and optimisation. Thequality of this stage singularly depends on the fundamental understanding of the physicsof di!usion in solids. We use atomistic simulations and continuum modelling in order toimprove TCAD results for di!usion of dopants in silicon. In this talk, I will outline theCowern model of variable charge-state di!usion and our results from quantum-theory-based simulations supporting this model.

GPS Software Receiver Approach to Mitigate Ionospheric ScintillationRajesh TiwariRoom 2.21, Day 1, Time 10.20amThe rapid random fluctuations in amplitude and/or phase of received transionosphericradio signals are termed ionospheric scintillation. Fast phase changes and/or deep ampli-tude fades can present a considerable problem to the tracking loop of the receiver PLLwhich can result in a significant positional error. Generally in the GPS receiver, the fad-ing from the scintillation causes the In-phase and Quadrature-phase of the received signalto be altered, resulting in large phase jitter in the tracking loop as it attempts to trackthe perturbed phase. Intense scintillation can not only degrade the signal quality but alsoresult in the receiver PLL loosing phase lock. In order to maintain GPS service duringstrong scintillation conditions, it is proposed that the PLL in a GPS software receiver beassisted with a scintillation prediction model that could modify the PLL settings duringstrong scintillation conditions such that it would be able to mitigate the scintillation ef-fect. This study focuses on a comparative study between a generic and a software GPSreceiver in ionospheric scintillation conditions to demonstrate the advantages of the latter.

Removing references from A2D conversionFei XiaRoom 2.22, Day 2, Time 9.00amConventional A2D conversion schemes usually require stable and known reference signalsof some kind, in most cases voltage, current, or time (frequency). The precision andaccuracy of the conversion are generally directly related to those of the reference signals.Is it possible to remove the dependency to such references in A2D conversion? Thispresentation introduces recent research in the MSD group attempting to address thisissue.

Local Solid Phase Epitaxy of Few-Layer Graphene on Silicon CarbideEnrique Escobedo-CousinRoom 2.22, Day 1, Time 10.20amGraphene consists of a single atomic layer of carbon atoms arranged in a specific config-uration that defines its physical properties. Its unique physical properties make an ex-tremely promising material for the post-silicon era. Graphene can o!er an exceptionally

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high electrical conductivity about 200 times higher than silicon. However, despite havingbeen known about since 1947, graphene remained a purely theoretical object for severaldecades due to the technological di"culties associated with producing single atomic lay-ers. It was first produced in 2004 by peeling o! the surface layer of a bulk graphitecrystal, a process known as exfoliation. Unfortunately, exfoliated graphene is availableonly in the form of micron-size flakes which are not suitable for electronic devices. Adi!erent approach consists on the thermal decomposition of a silicon carbide substrate,however, it is di"cult to control the graphene layer thickness and it requires a very highprocessing temperature which results in a defective graphene layer, also unsuitable forelectronic applications. In this work we explore an alternative graphene growth methodby local solid phase epitaxy from nickel silicide supersaturated with carbon. This growthtechnique may enable the production of high quality graphene layers that are compatiblewith standard microelectronic device processing.

Actuators for Aerospace High Lift Surfaces?John BennettRoom 2.21, Day 2, Time 10.40amA comparison of two strategies for an electromechanical actuator for aircraft flap systems.Alternative approaches for an actuator and electric drive design are described, showingwhere high-integrity monitoring and fault tolerance are required in the electric drive andthe control system. The chronological order of the projects and industrial input allowsconclusions to be made on the correct path for future electromechanical actuation andfault tolerant electric drives in aerospace.

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Abstracts

Communications and Signal Processing

Presentations

Automatic Threat Object Classification Based on Electromagnetic ImagingSystemAbdalrahman Al Qubaa, Gui Yun Tian, Wai Lok WooRoom 2.21 , Day 1 , Time 10.40amThe detection of concealed weapons is one of the biggest challenges facing the securitycommunity. It has been shown that each weapon can have a unique fingerprint, whichis an electromagnetic signal determined by its size, shape, and physical composition.Extracting the signature of each weapon is one of the major tasks of any detection system.In this paper, feature extraction of a new metal detector signal is conducted using aWavelet and Fourier Transform. These features used for object classification. ArtificialNeural network (ANN) and Support Vector Machines (SVM) classification techniquesare used to classify the metal objects towards automatic target classification. Promisingclassification accuracy rates are obtained from using individual and combination of thefeatures.

Low Frequency RFID Corrosion SensorMohammed Alamin, Gui Yun Tian, Je! NeashamRoom 2.21 , Day 1 , Time 10.55amIn this paper we present use of radio frequency identification (RFID) technology as asensor for corrosion detection. An RFID system consists of two components: the readerand tag/transponder. The tag is placed on a test sample surface and then measurementsare made using the reader coil at a certain height above the tag. The RFID corrosionsensor operates according to the principles of electromagnetic induction. The sample setconsists of coated and uncoated mild steel plates which have rectangular regions thathave been exposed to the environment for di!erent durations (1, 3, 6, 10 and 12 months)to create di!erent levels of corrosion. The results show that the RFID corrosion sensoris able to distinguish all the di!erent levels of corrosion. Furthermore, the measurementsfrom the corroded region are consistently di!erent from coating thickness and conductiv-ity/permeability variations across the sample surface.

An Investigation of Coating Thickness Measurement Using Eddy CurrentTechniqueIbukun Adewale, Gui Yun Tian, Said BoussaktaRoom 2.21 , Day 1 , Time 11.10amTo prolong the useful operations life of in-service key components in the petrochemicaland nuclear power plants, coating techniques are widely adopted for critical componentslike pipelines, tubes amongst others to prevent wall thinning and pitting. It is of utmostimportance that the integrity of such coating be measured for structural health monitor-ing and process control. The main thrust of this paper therefore, is to investigate the

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relationship between coating thickness and magnetic flux density via numerical simulationusing the Comsol Multiphysics software. Nondestructive evaluation using eddy currentinspection techniques have conventionally been investigated in terms of coil impedancesignal change via numerical and experimental approaches. However, recent advances usesolid state sensor for magnetic field measurements. This paper reveals that the real com-ponent of the magnetic flux density along the z-plane gives the best accuracy in thincoating thickness measurement.

Skin Chromaticity Gamuts for Illumination RecoveryStuart Crichton, Gui Yun Tian, Anya HurlbertRoom 2.21 , Day 1 , Time 11.25amColour constancy algorithms range from image statistics-based pixel intensity manipula-tion to gamut-mapping methods, and are generally independent of specific image contents.It has previously been demonstrated that natural polychromatic surfaces possess distinctchromatic signatures in cone-contrast space that may be exploited for colour constancy,and that in human vision, colour constancy is improved for such objects. Here we setout to use the specific, recognisable, and ubiquitous content of human skin in colourimages to drive a gamut mapping method for colour constancy. We characterise varia-tions in the chromaticity gamut of varying types of human skin (male, female; Caucasian,African, Asian) under varying illumination. We use a custom-built LED illuminator toproduce daylight metamers, and a spectroradiometrically calibrated hyperspectral cam-era to acquire images. We demonstrate that human skin gamuts in cone-contrast spaceare characterised by a set of features that can be used to di!erentiate between similarilluminations. This illumination recovery then enables invariant object colour recovery.

Ultra-Wideband Antenna for Breast Cancer DetectionAkinola Eesuola, Yifan Chen, Gui Yun TianRoom 2.21 , Day 1 , Time 11.40amA printed ellipse antenna with a v engraved on its ground plane is configured to illuminatea breast model with varying permittivity values and tissue materials. The impedancebandwidth of the antenna extends between 3.1 and better than 10.6GHz in the UWBband region. The return loss and impedance profile are evaluated and presented in orderto understand how to detect non-palpable breast cancer and imaging modality. Thedimension of the antenna is presented at 30 x 24 x 1.5mm. The antenna is compact, andsuitable for breast cancer imaging.

BER Performance of DCT Precoded DFT-OFDM System in Presence of HPAHussein Alsodani, Said Boussakta, Stephane Le Go!Room 2.21 , Day 1 , Time 1.05pmClipping within an orthogonal frequency division multiplexing (OFDM) signal becauseof a nonlinear high power amplifier (HPA) has a detrimental e!ect on the overall systembit-error-rate (BER) performance. This paper investigates the use of the discrete cosinetransform (DCT) as a channel independent precoder in OFDM based discrete Fouriertransform (DFT) systems, to reduce the peak-to-average power ratio (PAPR) and ulti-mately improves the BER performance in the presence of HPA. The BER performance of

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the DCT precoded DFTOFDM system in presence of HPA over a multipath channel ismathematically analysed and evaluated by simulation. The results, for di!erent channelmodels, modulation formats and input back-o! (IBO), show that the use of the DCT leadsto performance improvement compared to the selective mapping OFDM (SLM-OFDM)and partial transmit sequence OFDM (PTS-OFDM). The proposed approach also reducesthe PAPR by about 2.5dB and consequently reduces the clipping in transmitted signal.Additionally, the complexity of the proposed system is lower than the SLM-OFDM andPTS-OFDM systems.

On the E!ects of Network Geometry on Outage Performance of Wireless Net-worksAnvar Tukmanov, Said Boussakta, Zhiguo DingRoom 2.21 , Day 1 , Time 1.20pmSignal transmission over wireless channels is associated with a variety of factors, de-structively a!ecting the performance of a wireless communication system. Among thesemultipath propagation and signal attenuation due to path loss can be named as the mostwidely accounted for. However, only recently the joint e!ect of these two factors started tobe considered. In particular, to the best of authors’ knowledge, only few published worksexist up to date treating both channel and location randomness together. The importanceand impact of such combined analysis is that statistically more realistic system perfor-mance can be derived, leading to more accurate evaluation of communication protocols.The aim of this paper is to apply such joint description of multipath e!ects and networkgeometry to outage performance of a downlink communication scenario. We will showthat there is a significant performance di!erence between the two channel models. In ad-dition, provided analytical results, that tightly match simulation data, demonstrate thatwhile introduction of the location randomness into network model complicates deriva-tions, analysis of such models is feasible and can be applied to more complicated networksettings.

Assessment of the One-Dimensional GNMNT for Security SystemsNick Rutter, Alex Bystrov, Said BoussaktaRoom 2.21 , Day 1 , Time 1.35pmWith increased reliance on encryption for e-commerce, communications and data storage,new techniques are constantly being developed to meet the demand for secure encryptionsystems requiring high levels of security integrity. One aspect of integrity is the di!usionand avalanche e!ect, which is measured by its sensitivity to a single bit change betweenthe cipher text and the plaintext. This e!ect should yield a catastrophic result which ismeasurable and can therefore be readily assessed for its suitability as part of a securitysystem. This paper measures the one-dimensional implementations of the GeneralizedNew Mersenne Number Transform (GNMNT) suite for its suitability in security appli-cations. The GNMNT o!ers high flexibility owing to its long power of two transformlengths, e"cient calculations over a field of integers modulo a Mersenne prime and thecapability of implementations using fast algorithms.

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Area-of-Interest Extraction in Low Depth of Field ImagesGholamreza Rafiee, Satnam Dlay, Wai Lok WooRoom 2.21 , Day 1 , Time 1.50pmThis paper presents a low complex area-of-interest (AOI) detection and extraction tech-nique for low depth of field (DOF) images in two stages. The first stage is to grouplocal regions (i.e., blocks) in a joint contrast-energy feature space into three constituentclusters. To achieve this, we make use of a normal mixture-based model along with stan-dard expectation maximization (EM) algorithm. By defining a set rules and mergingthe blocks, the approach avoids the typical problem of local optima experienced in manymodels. As a result, significant blocks closely conforming to object regions are extracted.The second stage of the approach is to extract the regions in detail (i.e., at the pixellevel) by optimizing a threshold in di!erence of Gaussian function (DOG) and employ-ing morphological operations. Experimental results for a wide range of low DOF imagesdemonstrate that the approach is able to e!ectively recognize the AOI in low DOF imagesand is up to 10 times computationally faster than existing unsupervised approaches.

Single Channel Blind Separation Using Time-Frequency MaskingNaruephorn Tengtrairat, Wai Lok Woo, Satnam DlayRoom 2.21 , Day 1 , Time 2.05pmA novel low computational complexity single-channel blind source separation (SCBSS)algorithm is presented. The proposed algorithm is fast, independent of initializationcondition and does not require iterative optimization. The separation process consists oftwo steps: 1) Estimation of source characteristics where the source signals are modeled bythe autoregressive (AR) process. 2) Construction of masks using only the single-channelmixture. A new pseudo-stereo mixture is formulated by weighting and time-shifting theoriginal single-channel mixture. This creates an artificial mixing system whose parameterswill be estimated via our proposed weighted complex two-dimensional histogram. Finally,experimental testing on real-audio sources has been conducted to verify that the proposedalgorithm yields superior performance and is computationally very fast compared withexisting methods.

Single-Channel Audio Source Separation using Non-negative Hidden MarkovModelingPhetcharat Parathai, Wai Lok Woo, Satnam DlayRoom 2.21 , Day 1 , Time 2.20pmIn recent years, there is a growing interest in the field of single-channel audio sourceseparation (SCASS). SCASS concerns the separation of signals that have been mixed usinga single microphone. It has been broadly applied in various disciplines to automaticallyextract and track an audio signal of interest in the real-world scenarios. It is necessaryto handle hostile modeling with multiple audios whose characteristics vary rapidly withtime. The research will firstly focus on separation of two audio sources in single-channelsource separation tasks. A novel approach has been developed to extract better qualityof audio separated signals. This approach derives the non-negative hidden Markov model(N-HMM) to model a sound source by jointly learning several small spectral dictionaries.The N-HMM describes the fundamental structure of changes between these dictionaries.The algorithm is further developed for modelling sound mixtures leading to the non-negative factorial hidden Markov model (N-FHMM). The performance of the developedalgorithms is measured using real-time audio signals in terms of the signal-to-distortionratio.

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Investigation of a Full Duplex Acoustic Link for a Tetherless Micro-ROVGeraint Goodfellow, Je! Neasham, Bayan SharifRoom 2.21 , Day 1 , Time 3.00pmOver the last decade, vast improvements have been made in overcoming Inter SymbolInterference (ISI) in a dynamic underwater channel, with recent work focussing on multi-carrier systems due to their inherent multipath tolerance. However, the practical imple-mentation of a bi-directional link for a micro remotely operated vehicle (ROV) presentsadditional complications. Erratic acceleration poses a challenge to previously reportedDoppler compensation techniques, thus improvements in estimation and tracking are re-quired. The use of a singlecarrier scheme is demonstrated and critically evaluated inthe presence of severe Doppler and interference caused by the vehicle. Through the tun-ing of an adaptive closed loop Doppler compensation structure, single-carrier modulationschemes demonstrate reliable high data rate communications. Minimum latency is es-sential for precise control and simultaneous video transmission, which can be achievedthrough the use of an asymmetric full duplex link. In this paper, filtering techniques aredemonstrated to enable isolation of frequency multiplexed data streams and to preventsaturation of receiver circuitry. Results are presented demonstrating both single-carrierand multicarrier high data rate transmissions (¿30kbps) simultaneously with low datarate (¡100bps) control signals at distances of over 300m.

A Robust Techniques to Improve the OFDM System Performance in Non–Gaussian ChannelsSabah Nayyef, Charalampos Tsimendis, Bayan SharifRoom 2.21 , Day 1 , Time 3.15pmIn this work, two schemes are proposed to mitigate the impulsive noise impact on theorthogonal frequency division multiplex OFDM system. The contaminated samples arespread over N OFDM symbols through the use of an interleaver of depth N. Accordingly,the e!ect of the impulsive noise burst will be averaged over N OFDM symbols, which re-duces the impact on the bit error rate BER considerably. In general, the two schemes haveshown a superior improvement in BER performance compared to the standard OFDMsystem which su!ers from error floors at low values of signal to noise ratio SNRs. How-ever, for QPSK modulation with low signal to impulsive noise ration SIR, the scheme 2performs better than the scheme 1 for weakly, moderately, and heavily impulsive noisedistribution. For high modulation order 16, and 64QAM, the scheme 2 only has shownimprovement in BER for the SIR=-2 dB and weakly distributed impulsive noise.

Gabor Feature Fusion of Multimodal BiometricsMuhammad Ahmad, Satnam Dlay, Wai Lok WooRoom 2.21 , Day 1 , Time 3.30pmThe information fusion of face and palmprint biometrics is investigated. The proposedmethod uses global information derived from each orientation and scales of Gabor features,which are transformed to a compact feature space and concatenated to form a fusedfeature. Feature fusion of face and palmprint is performed on each orientation and scales ofthe Gabor image. The use of PCA and LDA methods significantly reduce the complexityof the feature vector while increasing the discriminant power in the feature space. Results

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of both identification and verification rates show significant improvement compared tothat achieved by single modal biometrics and several existing multimodal methods.

Multilinear Principal Component Analysis for Face RecognitionAbeer Al-Shiha, Satnam Dlay, Wai Lok WooRoom 2.21 , Day 1, Time 3.45pmMassive multidimensional images are being generated on a daily basis in various appli-cations. These natural images are the composite consequence of multiple factors andmodes, related to scene structure, illumination, imaging and viewpoint. Human percep-tion remains robust in spite of significant variation of all these factors. These factorsinclude di!erent facial expressions, head poses, and lighting conditions. Thus, there isrequiring for algorithms to extract useful information from this huge data that containsa large amount of redundancy. This is a challenging problem because of the large vari-ability and complex pattern distribution of multidimensional data. In order to solve thedimensionality reduction problem with a general tensor representation, this paper pro-posed an unsupervised method based on multilinear principal component analysis for facerecognition by extends the two dimensional principal component analyses (2DPCA) toits multilinear version. It employs to map high-dimensional data to a low-dimensionalspace to reduce the redundant data and to enhance the view based face recognition.

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Posters

Single Channel Speech Separation using Pitch ReconstructionQi Wang, Wai Lok Woo, Satnam DlayRoom 2.20 , Day 1 , Time 11.55amSingle Channel Signal Separation is a very popular research area within Machine Learningfor Signal Processing. Within this area are the research on sparse representation andseparation of di!erent types of signals. One of the most di"cult challenges of SCSSis separating speech signals. This is often known as the cocktail party problem; withspeakers speaking at the same time, and only one microphone is recording the information,it becomes a di"cult problem to separate signals of each speaker. This research is focusedon developing an algorithm which could solve the problem with quality. By quality,we mean that the results should be distinctly presentable, and that the computationcomplexity should be manageable. The research will take the most popular approach oftraining a statistical model and using it to enable separation.

Infra-Red Nano-Antennas for Solar Energy CollectionAhmed Sabaawi, Charalampos Tsimenidis, Bayan SharifRoom 2.20 , Day 1 , Time 11.55amIn this study, three nano-antennas have been designed: Dipole, Spiral, and Bow-tie infra-red (IR) antennas for solar energy collection. A performance comparison between thesedesigns is presented to find the optimum solution to this application. The main goal ofthis study is to design and optimize nano-antennas for maximum solar and earth radiationenergy conversion in the mid-IR region. The nano-antennas are simulated using COMSOLMultiphysics based on Finite element Method (FEM). The results demonstrate that theconverted electric field in spiral nano-antennas is larger than that in bow-tie and dipolenano-antennas. Furthermore, it is shown that the bow-tie nano-antenna exhibits a widerbandwidth when compared to the other types and that its electric field can be enhancedby coupling more bow-tie elements to form an array.

Localization and Data Management in Wireless Sensor NetworkWaleed Amer, Gui Yun Tian, Zhiguo DingRoom 2.20 , Day 1 , Time 11.55amThe aim of this project is to design and develop a WSN with dynamic localisation tech-nique for environmental monitoring and smart cities. The WSN will be able to operateunattended under conditions of random deployment and/or mobile nodes. This WSNwould represent a group of sensor nodes attached to pedestrian/car (wearable sensor,smart phones, navigation gadgets, health care, etc.) that are able to communicate witheach other and form temporary clusters and to report events in the area of concern asrequested by a base station. The specific objective can be outlined as: Develop a newlocalisation algorithm extending from other works to encounter a mechanism to triggerthe start of localisation process upon detecting of enough nodes in the neighbourhood aswell as the event to be monitored.

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Physical Layer Network Coding with Turbo Equalization for Realistic Wire-less ChannelsAlaa Al Rubaie, Bayan Sharif, Charalampos TsimenidisRoom 2.20 , Day 1, Time 11.55amPhysical layer network coding (PNC) is a technique that exploits the additive propertyof arriving signals at a relay to achieve the capacity of the wireless network. Relay nodesin the network perform PNC on all incoming signals and map the sum of the signals to abinary sequence that is most likely to be the exclusive OR of the source messages. Thisis re-modulated at the relay and broadcast to all destination nodes, which acquire theirdesired message by performing an exclusive OR operation on the demodulated receivedbinary sequence and their own original message, thus obtaining the other user’s message/

Secrecy Capacity for Bit-Interleaved Coded Modulation SchemesWeichen Xiang, Zhiguo Ding, Stephane Le Go!Room 2.20 , Day 1, Time 11.55amThe design of high secrecy capacity BICM system are investigated in this paper. Inspiredby mapping schemes can a!ect the channel capacity, we studied the secrecy capacity ofvarious mapping schemes of BICM over Ergodic fading channels. The results indicatethat under secrecy constraint, Gray mapping is not the optimal choice for 16QAM as itperforms least achievable secrecy capacity. The average number of bits that di!er fromneighbor signals and the harmonic mean of minimum squared Euclidean distance are thekey parameters to design a high secrecy capacity BICM system.

Performance Analysis of PNC and IDMA Based Relay system in TWRCSankar Qader, Charalampos Tsimenidis, Bayan Sharif, Zhiguo DingRoom 2.20 , Day 1, Time 11.55amIn two-way relay channel (TWRC), two nodes are communicating with each other assistedby the relay node. For such scenario, three time slots are necessary in straightforwardnetwork coding (SNC) for data transmission from user to user while in the physical net-work coding (PNC) two time slots are enough due to exploiting natural network codingby superimposed electromagnetic waves EM. Within PNC, instead of detecting each usersdata, the relay is estimating the (XOR) bits of the two users bits. In another hand, mul-tiple user detection (MUD) can also be used for user data detection. One of the recentlyproposed schemes of MUD is Interleaved Division Multiple Access IDMA, which uses chiplevel interleavers for user separation. System performance of PNC and IDMA based relaysystems is compared in both AWGN and Rayleigh channels, and the complexity of bothsystems have been investigated.

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Source Separation from Single-Channel SignalsKaiwen Yu, Je! Neasham, Wai Lok WooRoom 2.20 , Day 1, Time 11.55amSignal separation in reverberant environment blind signal separation (BSS) has attracteda great deal of attention in signal analysis and processing fields. It attempts to discoverfrom observed signals a set of unobserved and underlying sources that are as statisticallyindependent as possible. BSS assumes that signals are generated by several (independent)sources, whose properties are unknown but merely assumed non-Gaussian distributed. Inlinear BSS, the observed signals are linear combinations or convolutions of these sources,though the mixing characters are unknown a priori. It then decomposes them based onentropy information or maximum likelihood criteria. Hence, BSS is highly suited as apractical method for feature extraction and signal enhancement for voice signal. Thehypothesis to be investigated is that state-of-the-art signal separation and enhancementcan be achieved only by realistic modelling of the voice signals and the reverberant mixingenvironment. The topic I am doing is the separation of a single channel signal. And inthis period, I am working on the methods based on ICA algorithm.

Advanced Design for MIMO and Cooperative SystemsTong Chen, Zhiguo DingRoom 2.20 , Day 1, Time 11.55amWireless communication systems su!er severe degradation due to fading e!ects causedby multi-path propagation. Diversity has been considered as an e!ective technique tocombat the deleterious e!ects of fading, which is achieved by independently transmittingcopies of the same signal. Wireless networks normally use one or more forms of diversity,such as spatial, time, frequency and polarization. Among them spatial diversity, alsonamed MIMO, has been of interest as it does not sacrifice precious bandwidth resource.Recently it has been shown that cooperative communication can provide the benefitsof spatial diversity without the need for physical antenna arrays. The key idea of suchcooperative communication is that several terminals form a cluster to assist each otherwith transmission of their message. The aim of this project is how to design spectrale"cient cooperative transmission protocols to mitigate wireless channel impairment.

Multi-Modal Biometric System Using Statistical AnalysisCharles Ukpai, Hal Strangeways, Said BoussaktaRoom 2.20 , Day 1, Time 11.55amWith the increase in identify fraud and emphasis on security, there is a growing and ur-gent need for e"cient authentication system for proper recognition of persons both locallyand remotely on a routine basis. The conventional authentication system which is basedon what a person knows (e.g. password) or what a person has (e.g. electronic card)is ine!ective and leads to breach of security. Authentication based on the physical orbehavioural (Biometrics) features possessed by an individual has proven to more e!ectiveas it is di"cult to forge and cannot authenticate in proxy. Although biometrics is themost e"cient authentication system available today, it is still saddled with the problemsof universality, acceptability and user co-operation. Our research here uses statistical ap-proach to develop a multi-modal biometrics system combining behavioural (Keystroke)and physical (iris) biometrics to form a cost e!ective user authentication system which ismore universal, acceptable and requires less user co-operation. The Multi-modal biomet-rics system is shown to perform better then the single biometric system and it is more

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e"cient at authenticating users of computer and other end devices/services like ATM,POS, online transaction, online banking compared to the conventional system.

Screening Elderly population at Risk (Frail) Using Parameters Derived fromTUG-T Using AccelerometersSathish Sankarpandi, Satnam Dlay, Wai Lok WooRoom 2.20 , Day 1, Time 11.55amFrailty, generally can be defined as loss or dysfunction of skeletal muscles and bones. Itis considered as a condition lying between sicknesses and being healthy. Frailty increasesmortality, co-morbidity rate and subsequently increasing the health care expenditure.Therefore it needs to be screened and assessed in the early stages so that a proper inter-vention can be provided to reduce the adverse outcomes in the future. Clinical assessmentof frailty is based on qualitative analysis and it is not standardised, requires long timefor assessment. Quantitative measurements of frailty using instruments (accelerometers)allow assessing frailty quickly, providing general, standard and more accurate solution.The present study focus on extracting information about current/future health (frailty)from dynamics of the movement obtained from accelerometers data of timed-up and gotest using multi resolution analysis (CWT, DWT).

Mitigation of Scintillaiton E!ects on Global Navigation Satellite Systems(GNSS)Arslan Ahmed, Zhiguo DingRoom 2.20 , Day 1, Time 11.55amThe Global Positioning System (GPS) has wide applications which include aviation, ma-rine navigation in addition to life saving services thus the expectation of its availability,accuracy and reliability is very important. However, ionospheric irregularities degradesthe transionospheric radio waves causing random fluctuation in phase or/and amplitudeof the received signal termed ionospheric scintillation. This research focuses on mitiga-tion of the e!ects of scintillation by using a combined hardware and software techniquewhich is part of an EPSRC project awarded to Newcastle University in conjunction withlinked awards at, Nottingham and Bath Universities. The aforementioned objective willbe achieved in three phases; i) investigation of ionospheric scintillation at GNSS(GlobalNavigation Satellite System) frequencies at di!erent latitudes; ii) designing an intelligentsoftware receiver including scintillation prediction based on previous measurements iii)the software GPS receiver will be designed to have configurable hardware. New mitiga-tion method/ methods will be evaluated and compared with previous mitigation strategiesusing real 50 Hz GPS data.

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Emerging Technologies and Materials

Presentations

Electronic and Structural Properties of (001) Diamond with Monolayer andSubmonolayer Coverages of Transition MetalsAmit Tiwari, Alton Horsfall, Jonathan Goss,Room 2.22 , Day 1, Time 10.40amThe presence of adsorbates on a diamond surface, even in small proportions, may influenceits electrical, chemical and structural properties. Despite the vast potential for numer-ous applications, submonolayer coverages of transtion metals on diamond have not beenstudied. We have performed density functional calculations examining up to a monolayerof selected transition metals (Cu, Ni, Ti and V) on the 2 1 reconstructed diamond (001)surface. We find that addition of the carbide forming metals (Ti and V) results in sig-nificantly higher binding adsorption energies at all surface coverages relative to those ofthe non-carbide-forming metals. For monolayer coverage by Cu or Ni, and sub-monolayercoverage by Ti and V, we observe a negative electron a"nity. We propose that basedupon the electron a"nities and binding energies, metal coated 21 reconstructed (001)diamond surfaces are promising candidates for negative electron a"nity devices.

High Aspect Ratio Spike Electrodes for Intracellular ApplicationsLeonie Cunnington, Alton Horsfall, Miles WhittingtonRoom 2.22 , Day 1, Time 10.55amCurrent intracellular techniques in electrophysiology only allow for the use of single glasscapillary electrodes. Hence, scientists are limited to the number of useable electrodes bythe number of micromanipulators that can be comfortably placed around the recordingchamber. This project is dedicated to the development of a high aspect ratio siliconspike electrode array for intracellular measurements. Individual spikes are produced frompillars created using deep reactive ion etching and a sharpening process performed byreactive ion etching. Reproducible spikes with a height of approximately 220microns anda tip diameter of approximately 125nm were successfully attained from lightly dopedsilicon. This paper will discuss the di!erent steps taken to obtain this outcome and thesubsequent steps to produce an electrically isolated and usable spike electrode.

A New SiC/SOI-based PWM Generator for SiC-based Power Converters inHarsh EnvironmentsOmid Mostaghimi, Alton Horsfall, Nick WrightRoom 2.22 , Day 1, Time 11.10amWide bandgap semiconductors, such as Silicon Carbide (SiC), have attracted a greatdeal of attention for power electronic applications, as they o!er numerous advantagescompared to their Silicon counterparts. The high thermal-conductivity and carrier drift-velocity of SiC o!er high temperature (HT) and faster switching capability, which resultin reduced cooling requirements and smaller passive components. This allows higherdensity power electronic converters, which are necessary for on-board payload systems tobe realised. Since switching losses dominate conduction losses at higher frequencies, the

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use of SiC devices will be superior and higher e"ciencies can be achieved. The desire toplace the gate driver physically close to the SiC power switches in the converter, leads tothe necessity of a temperature resilient PWM generator to control the power electronicsmodule. The novelty of this work is in the first demonstration of a SiC/SOI based PWMand control circuit with SiC power semiconductor devices, which can demonstrate a fullrange of duty cycle.

1/f Noise Characteristics in 4H-SiC JFETs Under the E!ect of ProlongedThermal StressHua Khee Chan, Alton Horsfall, Nick Wright, Jonathan Goss,Room 2.22 , Day 1, Time 11.25amThe low frequency noise characteristics of 4H-SiC low-level signal lateral JFETs have beenstudied under prolonged thermal stress. We studied the e!ect of long term 400oC and500oC exposure to emulate the typical operating conditions of Silicon Carbide devices.The thermally stressed devices showed a significant change in both DC parameters andnoise characteristics. I-V data exhibits a monotonic decrease in drain-source saturationcurrent with increasing soak temperature, whilst the Normalised Power Spectral Densityof the low frequency noise increases significantly only for devices soaked at 500oC. The ti-tanium flash-layer within the source/drain contact metallisation was found to be oxidisedin the 500oC sample, resulting in Poole-Frenkel emission limited current in the sourcedrain contacts. Hence we describe the increase in the noise as the addition of a trap as-sisted generation-recombination process, which is linked to the existence of Poole-Frenkelemission.

Direct Frequency Modulation of a High Temperature SiC OscillatorDan Brennan, Alton Horsfall, Nick WrightRoom 2.22, Day 1, Time 11.40amThis paper reports on direct frequency modulation of a RF Colpitts oscillator, realisedfrom silicon carbide devices and proprietary components, capable of transmitting sensordata whilst operating at 300C. Utilizing a reversed biased Schottky diode as a varactorin an LC oscillator, it is possible to modulate the frequency of an RF carrier by applyingexternal voltage signals. These experiments have shown that a 10V bias will increase thefrequency by as much as 10%, however signals as low as 10mV are easily detectable withstandard silicon receivers.

Carbon Impurities in Strontium Titanate from First PrinciplesMeaad Al-hadidi, Patrick Briddon, Jonathan GossRoom 2.22 , Day 1, Time 1.25pmRecently, perovskite oxides have attracted both experimental and theoretical attention.An important example of this type of material is SrTiO3 (STO), which is used in anumber of applications including optoelectronics, waveguides, high capacity computermemory cells and dielectrics. Of particular interest is the replacement of the native oxidein silicon transistors by materials such as STO, which takes advantage of its relativelylarge static dielectric constant. STO films are often grown using organic precursors andcarbon contamination is highly probable. The properties of carbon defects in STO are

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calculated using the first principles density functional theory software, AIMPRO. Thecalculated properties agree well with literature values for bulk STO. Important electricaland dielectric e!ects of carbon substitution of host atoms are obtained suggesting thathigh levels of carbon contamination may not result in electrical doping. The impact uponthe dielectric constant is reviewed in this paper.

Density Functional Simulations of Point Defects in Diamond Using the Fil-tration TechniqueFadil Shrif, Patrick Briddon, Jonathan GossRoom 2.22 , Day 1, Time 1.40pmAb initio modelling techniques are widely used to examine models of atomic systems;density functional methods have become the method of choice for this goal. We test arecent innovation in this technique, the filtration method, in a study of the P1 defectcentre in diamond. The purpose of this work is to assess the extent to which the resultsof the filtration method agree with previous calculated values. A comparison with ex-periment is also given. It is shown that for (LVMs), the filtration method agrees withstandard density functional theory to within (2%); the valence band structure agrees towithin (0.03 eV) an error much smaller than the valence band width of bulk diamond(21eV). It is concluded that the filtration method works with a good performance andhigh e"ciency, also it has succeeded in keeping the accuracy of the calculations largelyuna!ected and minimises the consumed computational time.

Faster Determination of Transition State StructuresAndrew Lawson, Patrick Briddon, Jonathan GossRoom 2.22 , Day 1, Time 1.55pmIn computational chemistry, the determination of a transition state structure along withits energy, gives us access to information such as the activation energy for a reaction,useful for determining rates of reaction. On a potential energy surface (PES) transitionstates can be found by searching for first order saddle points. Unlike simple structuraloptimsation where energy is minimised for all directions on the PES, the energy has to bemaximised in one direction. This requirement prohibits the use of standard minimisationalgorithms. Currently this problem would typically be solved using the nudged elasticband (NEB) method. The main drawback of this method is that is uses multiple connectedimages, which greatly increase the computational time. Here, a single image method isexamined known as the Lanczos method to see if it can reproduce the NEB results in afraction of the time for a set of structures known as the Baker set. The best use of themethod in conjuction with the NEB method is also examined.

Quantum Mechanical Calculations of Oxygen Vacancy Migration in Bi-axialStrained SrTiO3Raied Al-Hamadany, Jonathan Goss, Patrick BriddonRoom 2.22 , Day 1, Time 2.10pmStrontium Titanate (SrTiO3) is a highly promising perovskite for many applications suchas MIM capacitor, due to the high dielectric constant and Ferroelectric. Oxygen vacanciesare believed to have noticeable contribution to trap electrons, leading to undesirable

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leakage current in the MIM capacitor. In contact with dissimilar lattice constant metal,SrTiO3 undergoes to a bi-axial strain which has significant impact upon the electricaland electronic properties. In assessing the influence of the bi-axial lattice strain on thedi!usivity of oxygen vacancy in distortive SrTiO3, calculations were carried out usingthe computer code AIMPRO. In these calculations, two lattice parameters were fixed todi!erent values of strain and the remaining lattice parameter permitted to relax. A cubicsymmetric to ferroelectric phase transition in SrTiO3 under biaxial, compressive andtensile, strain has been obtained. The results show clear dependence of oxygen vacancymigration upon the bi-axial strain within and normal to the plane of strain.

Hyperfine Interactions at Nitrogen Interstitial Defects in DiamondMohammed Atumi, Jonathan Goss, Patrick BriddonRoom 2.22 , Day 1, Time 2.25pmDiamond has many extreme physical properties and it can be used in wide range of ap-plications. In particular it is a highly e!ect particle detection material, where radiationdamage is an important consideration. The WAR9 and WAR10 are electron paramag-netic resonance defects seen in irradiated, nitrogen-containing diamond. These defectshave C2v and C1h symmetry, respectively, and both have an S = 1/2 ground state, andthe experimental spectra have been interpreted as arising from nitrogen split-interstitialcentres. Based upon the experimental and theoretical understanding of interstitial nitro-gen defect structures, the AIMPRO density functional code has been used to assess theassignments for the structures of WAR9 and WAR10. The results of calculated electron-nuclear -spin hyperfine-interactions show the model for WAR9 is plausible, whereas thecalculated directions of hyperfine tensor are in disagreement for WAR10. Alternativemodels are discussed in this paper.

Surface Roughness Characterisation of Strained Silicon Structures Using AFMFerran Urena, Sarah Olsen, Nick CowernRoom 2.22 , Day 1, Time 3.00pmAlmost every real surface is rough at a microscopic level. Surface and interface rough-ness are considered to play a very important role in current semiconductor technologyespecially in thin film and nanowire based devices where the surface-to-volume ratio isquickly increasing. Many electrical and mechanical properties e.g. electrical conductivityare controlled by interface roughness which directly depends on the di!erent chemical andmechanical processes used during the fabrication stage. Correspondingly, strain engineer-ing is nowadays highly used for fabricating micro- and nano-electromechanical systems(MEMS and NEMS) e.g. piezoresistive sensors while in microelectronics strain is usedto enhance mobility in metal-oxide-semiconductor field-e!ect transistors (MOSFETs). Inthis paper, we present the results obtained using atomic force microscopy (AFM) to char-acterise surface roughness in silicon structures under tensile stress in terms of the mainstatistical parameters used to describe a rough surface.

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Influence of Oxygen Vacancies on Resistive Switching Behaviour of Pt/SrTiO3/PtCapacitorShahin Ameiryan, Anthony O’Neill, Jonathan GossRoom 2.22 , Day 1, Time 3.15pmResistive switching phenomena in metal/oxide/metal junctions have attracted consider-able attention due to their potential for nonvolatile memory devices. Resistive switchingis defined as the ability to switch the state of oxide resistance between high and lowresistance states by changing the polarity of the bias voltage. In this study, the resis-tive switching behavior of SrTiO3 is investigated by analyzing the J-V characteristics ofPt/SrTiO3/Pt capacitors over the temperature range 280 K to 400 K. The polarity asym-metry of the current was observed at low temperatures while resistive switching occursat high temperatures. The asymmetry of current is explained by lack of oxygen vacanciesat the bottom metal electrode interface region. This was proved by driving the oxygenvacancies near the bottom electrode interface, resulting in a symmetric J-V characteristicat room temperature. The resistive switching phenomenon originates from di!usion ofoxygen vacancies at high temperatures.

A Further Use for Ferroelectrics?Daniel Appleby, Anthony O’Neill, Kelvin KwaRoom 2.22 , Day 1, Time 3.30pmThe demonstration of negative capacitance in a MOSFET utilizing a ferroelectric filmin the gate stack may allow the progression of ’Moore’s law’. It could lead to reducedvoltage levels and lower o!-state power dissipation through a reduced subthreshold swingwhich is currently the limiting factor in future scaling of transistors. Ferroelectrics arealready well used in electronic devices, primarily down to the application of thin filmsallowing correct voltage levels to be used to implement memory devices. In additionto memory cells utilizing ferroelectrics, sensor applications can be designed due to theirpyroelectric and piezoelectric properties. While these properties o!er a diverse range ofapplications, the prediction of negative capacitance arising in the ferroelectric is not verywell understood. This paper will explain the idea behind the inclusion of a ferroelectricmaterial in the MOSFET gate stack utilizing the negative capacitance property.

Estimation of Nanostructural E!ects in Pulsed Laser Deposited Barium Ti-tanateNikhil Ponon, Kelvin Kwa, Anthony O’NeillRoom 2.22 , Day 1, Time 3.45pmBarium titanate (BTO) is a ferroelectric material which shows ferroelectric properties atroom temperature. BTO could be used in the gate stack of a transistor to increase theswitching speed and reduce the power consumption by the virtue of negative capacitancee!ect shown by them. However, the material and electrical properties of the depositedfilm plays a crucial role in achieving this feature. X-ray di!raction (XRD) is a power-ful technique to estimate the material properties such as crystallinity, phase, grain size,strain etc. of a crystalline material. In this paper, XRD is employed to estimate thecrystallographic properties of pulsed laser deposited (PLD) BTO. An average grain sizeof 100 nm was obtained using XRD and these values were confirmed by atomic forcemicroscopy images. Raman spectra showed that BTO prepared by PLD at 740 o C isdominated by cubic phase with a small presence of tetragonal phase.

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Electrical Properties of Silicon NanowiresSami Ramadan, Kelvin Kwa, Anthony O’NeillRoom 2.22 , Day 1, Time 4.00pmNanowires are candidates to be one of the most promising building blocks for future na-noelectronics, due to their distinctive properties including high surface to volume ratio,electrostatic properties and diameter. However, it is challenging to obtain the optimalelectrical and electronic characteristics of the fabricated nanowires. In this paper, siliconnanowires are fabricated using a top-down method which involves conventional lithogra-phy, thermal oxidation and anisotropic wet etching. The electrical transport performedusing two and four-point probes measurements, shows that these devices have high con-tact resistance and almost rectifying I-V curves. After annealing at 4508304;C for 15minutes, the specific contact resistivity is enhanced by about three orders of magnitudeand an almost ohmic curve of I-V is obtained. It is expected that the interface qualitybetween metal/SINWs improves after annealing process.

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Posters

Vacuum Thermo-Tunnelling Devices for Power Generation ApplicationsKelebogile Maabong, Nick Cowern, Jonathan GossRoom 2.20 , Day 1 , Time 11.55amA brief overview of the project is presented. Vacuum thermo-tunnelling systems with avacuum gap in few nanometers scale have attracted attention as direct heat to electricityconversion systems for power generation and cooling applications. Energy conversionis achieved through a net tunnelling current as a result of tunneling electrons combinedwith temperature di!erence between the electrodes. A requirement for low work functionsmaterials for emitter and collector electrodes and transport of electrons through the tunneljunction present challenges in achieving su"cient net currents. The aim is to conductresearch that will lead to production of vacuum gap structure with a potential to convertheat to electricity as a result of tunneling electrons and temperature di!erence. Di!erentmaterial surfaces and methods to develop optimal geometric features to maintain the gapwill be explored

Evaluation of the Charge Pumping Technique for the Characterisation of theSiC/SiO2 Interface in 4H-SiC MOSFETs.Lucy Martin, Alton Horsfall, Nicholas WrightRoom 2.20 , Day 1, Time 11.55amOne of the key issues in the realisation of SiC metal-oxide-semiconductor field e!ect tran-sistors is the high interface trap density at the semiconductor-dielectric interface. In orderto improve the technology a thorough understanding of the interface needs to be devel-oped. Charge pumping is a measurement technique used to analyse the semiconductor-dielectric interface of MOS structures and is a widely used analysis tool in silicon tech-nology. Information about the quality and degradation of a device can be extracted fromcharge pumping measurements. This technique has the potential to create a thoroughunderstanding of the amount as well as the energy level and position of interface statesthroughout the entire band gap of MOS transistors. This work outlines an initial inves-tigation into the di!erences between charge pumping on Si devices and SiC devices andexamines the potential of the technique within SiC technology.

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Microelectronics System Design

Presentations

Error Detection and Correction of Single Event Upset (SEU) Tolerant LatchNorhuzaimin Julai, Alex Yakovlev, Gordon Russell, Alex BystrovRoom 2.22, Day 2, Time 9.20amSingle event upset (SEU) caused by soft error is a serious concern in state holders as it cancause data to be corrupted by temporarily change the state of state holder. The corrupteddata from the state holder could propagate to the whole system causing the system tobecome malfunction. The term soft error refers to the temporarily error that is due to theparticle strike provided the su"cient current and with certain width of current pulse isneeded to cause the state change. In this paper we are focusing on C-elements since it isone of the state holders that are used widely in asynchronous circuit. Our investigationsfocus on the vulnerability of di!erent types of C-element-based latches towards soft errors.Our aim is to design single event upset (SEU) tolerant latch that has the capabilities ofdetecting and correcting soft error based on Razor flip flop implementation. In the eventof SEU hitting sensitive nodes and caused the state to temporarily change, a shadow latchrestores the correct data. We have demonstrated the functionality of our proposed latchby simulating the design using UMC90nm technology.

A Game Theoretic Real-Time SchedulerJames Docherty, Alex Yakovlev, Alex BystrovRoom 2.22, Day 2, Time 9.35amAs the number of embedded systems increases, so do the demands placed upon them. Cur-rent real-time algorithms are capable of creating optimal schedules under ideal conditions,but can be considered inadequate when many variables must be considered. End users aredemanding ever greater performance while minimizing failures and power consumption,meaning advanced power management must be incorporated into circuit designs, espe-cially in multi-core environments. This paper summarizes the initial investigation into theuse of Game Theory to create a scheduler for the next generation of embedded real-timesystems. By using game theory and a heuristic approach, the aim is to create a schedulercapable of performing at a similar level to established algorithms while also decreasingconsumed power within the package to a level comparable with an expert system; as sucha system can be considered impractical to create for every possible usage environment.

Reference Free Voltage Sensing Using an Asynchronous Charge-to-DigitalConverter for Energy Harvesting CircuitsReza Ramezani, Alex Bystrov, Alex YakovlevRoom 2.22, Day 2, Time 9.50amEnergy harvesting generators deliver nondeterministic power density depending on en-vironmental conditions. In response to such variability of power, this paper presents anovel reference free voltage sensor. This sensor consists of a capacitor that samples themeasured input voltage, an asynchronous counter powered by the charge on the capac-itor and a control to organize the entire process. In this design, the switching activity

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of the counter is a function of energy stored in the capacitor. The control monitors thevoltage dropping on the capacitor as it discharges. It latches the output of the counterright before this capacitor discharges completely. An acknowledgement signal is issuedafterwards. The numerical result of the charge-to-digital conversion reflects the sampledvoltage. The robustness of the design is examined using Cadence tools at the 180nmtechnology node. Such a sensor can be readily adopted in energy harvesting systems foron-chip dynamic power management.

Formal Modelling and Transformations of ProcessorMaxim Rykunov, Andrey Mokhov, Danil Sokolov, Alex YakovlevRoom 2.22, Day 2, Time 10.05amInstruction sets of modern processors contain hundreds of instructions defined on a rela-tively small set of datapath components and distinguished by their codes and the orderin which they activate these components. Optimal design of an instruction set for aparticular combination of available hardware components and software requirements iscrucial for system performance and is a challenging task involving a lot of heuristics andhigh-level design decisions. The overall design process is significantly complicated by in-e"cient representation of instructions, which are usually described individually despitethe fact that they share a lot of common behavioural patterns. This paper presents anew methodology for compact graph representation of processor instruction sets, whichgives the designer a new high-level perspective for reasoning on large sets of instructionswithout having to look at each of them individually. This opens the way for varioustransformation and optimisation procedures, which are formally defined and explainedon several examples, as well as practically evaluated on an FPGA platform.

Behaviour of Latches Under Dynamic Vdd OperationIoannis Syranidis, Fei Xia, Alex YakovlevRoom 2.22, Day 2, Time 10.40amPower supply voltage of cmos circuits has in most cases been considered fixed to a constantvalue. Power aware design and the emergence of new trends in system design challengethis fact. Systems that operate with a battery, circuits for energy harvesting applicationsthat depend on small external amount of energy and designs that on the fly adjust supplyvoltage to meet performance and power requirements are a few examples. In this pa-per, we present many interesting phenomena taking place in circuits that operate underdynamically varying supply voltages and discuss possible implications or opportunitiesthat emerge. Following our previous work on the bifurcation analysis in True SinglePhase Clock (TSPC) latches we expand the range of circuits under consideration andfurthermore present a dynamical point of view analysis of a bistable memory element.

FPGA Voltage Sensing Using Flip-Flop MetastabilityGhaith Tarawneh, Terrence Mak, Alex YakovlevRoom 2.22, Day 2, Time 10.55amFlip-flops with asynchronously generated inputs often exhibit prolonged clock-to-q tran-sitions due to the occurrence of metastable states. Typically, this is an undesired e!ectbecause it can give raise to unpredictable system failures. In this work, this phenomenon

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is exploited to implement an FPGA voltage sensor with a higher precision and a re-duced area overhead compared to typical FPGA-based voltage sensors. Results from animplementation on an Altera Cyclone II device are presented.

Dynamic On-Chip Thermal Optimization for 3D Networks-on-ChipRa’ed Al-Dujaily, Terrence Mak, Fei Xia, Alex YakovlevRoom 2.22, Day 2, Time 11.10amThe high-density TSV-based 3D integration could lead to ultra-high temperature hotspotsand permanents silicon device damage. In this paper, we introduce an adaptive strategyto e!ectively di!use heat throughout the 3D geometry. This strategy employs a dynamicprogramming network to select and optimize the direction of data maneuver in a networks-on-chip. We also developed a tool, which is based on the accurate HotSpot thermal modeland SystemC cycle accurate model, to simulate the thermal system and evaluate ourapproach. We found that the proposed approach can significantly di!use the hotspotsfrom a 3D geometry and maximum temperate can be reduced by 4oC. Given the samethermal constrains, the throughput performance of an adaptive NoC can also be improvedby 20%. This work enables a new avenue to explore the on-chip adaptability for the futurelarge-scale 3D integration.

Machine-assisted Formalisation of Parametrised Graph AlgebraArseniy Alekseyev, Alex Bystrov, Alex YakovlevRoom 2.22, Day 2, Time 11.25amThe paper shows a machine-assisted approach to formal modelling by considering a graph-based model used to describe parametrised systems of causally related events, such asmicrocontrol circuits. The paper gives a formal description of the model encoded withthe type system of Agda programming language, defining it as an arbitrary set withspecific operations on its members, forming an algebra. The data structure for formulaeof this algebra is then introduced to be used as a representation type for the model. Anexample of an algorithm manipulating the formulae is shown. The algorithm correctnessand termination are proven with each proof being checked by the compiler. The resultis both a machine-verifiable formal proof of the theorems and a runnable tool for theformula manipulation.

Comparision of Robustness in SynchronizersMohammed Alshaikh, Alex Yakovlev, Gordon RussellRoom 2.22, Day 2, Time 11.40amAs integrated circuits technology sizes shrink, variability in process parameters, suchas the threshold voltage, are expected to increase and become worse under low supplyvoltage (VDD). Circuit parameters, such as the propagation delay in logic gates and theresolution time from metastability in flip-flops, will vary more. As a consequence, the syn-chronizer failure rate would be unpredictable. In this paper, we review by the concepts ofconventional cascaded flip-flops synchronizer and wagging synchronizers, particularly howthe wagging synchronizer can tolerate such variability. After that, based on simulationresults, we compared the performance of these synchronizer circuits in terms of toleratingprocess variations under nominal and low Vdd, this included resolution time constant,

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MTBF and latency. wagging to a synchronizer, and show that a significant increase inreliability can be obtained over the conventional cascaded two flip-flop synchronizer.

Adaptive CFA Image Compression AlgorithmSaad Al-Azawi, Said Boussakta, Alex YakovlevRoom 2.20, Day 2, Time 1.55pmColour Filter Array images (CFA) can represent any colour image with only one plane,with half values for green, and one quarter each for red and blue colours. The three colourplane can be extracted using di!erent types of interpolation method. Many algorithmshave been published for CFA image compression that combine JPEG with a colour sep-aration process. However, these algorithms are not suitable for small or mobile devicesdue to their high complexity. This paper introduces a low complex adaptive compressionalgorithm for CFA. The proposed algorithm decomposes the CFA image into two or fourcolour planes. Each colour plane is partitioned into fixed size non-overlapping blocks. Theencoding type of each block was determined according to the standard deviation. Lowstandard deviation blocks were encoded using selected moments. The moments that wereexplored in this paper were mean, maximum, minimum, median and a mixture of these.Other blocks were encoded according to the experiments with a quantizer composite of 32and 16 levels. The stated procedures enabled good performance for such types of imagesby adjusting the quantization levels and the thresholds. Depending on the texture typeof the experimented images, the proposed algorithm produced a PSNR of 25-40 dB for acompression ratio of four.

Modelling and Impact Analysis of Power Supply Noise in Networks-on-ChipNizar Dahir, Terrence Mak, Alex YakovlevRoom 2.20, Day 2, Time 2.10pmNetworks-on-chip (NoC), dictates the power dissipation and overall system performance inmulti-core systems and emerging embedded computing architectures. These new commu-nication centric architectures require dedicated power grid model that embeds distinctivecommunication characteristics and spatial parameters for analyzing impacts of on-chipvoltage variations. In this paper, we present a compact power delivery model that enablescommunication-centric power grid simulation and spatial-temporal design analysis. Thismodel enables novel analysis of power delivery integrity and, particularly, the impacts ofVDD variations and clock skews. This step is essential to predict the timing reliability ofa data path in the presence of power supply variations. Significant VDD variations havebeen identified on real applications that can cause up to 39% increase of clock skew.

E"cient FPGA-based Implementation for Twelve Parallel 3-D fMRI FilteringAlgorithmsSami Hasan, Said Boussakta , Alex YakovlevRoom 2.20, Day 2, Time 2.25pmTwelve di!erent parallel 3-D fMRI filtering algorithms are e"ciently implemented in asingle reconfigurable architecture using Xilinx System Generator. The single architectureis behaviourally prototyped to achieve high filtering performance of (140 frames/second)throughput per minimum power consumption of (0.75 Watt at junction temperature =

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25 C9675;) and up to (1.157 Watt at junction temperature = 75 C9675;) at a maximumsampling frequency of (230 MHz) targeting Virtex-6 xc6vlX130Tl-1l!1156 FPGA board.The boosted FPGA-based implementation performance results (in terms of power, speedand area) are obtained, evaluated and compared with other existing systems. The twelvedi!erent parallel 3-D fMRI filtering algorithms are Edge, Vertical Edge, Sobel X, SobelY, Sobel XY, Blur, Smooth, Sharpen, Gaussian, Prewitt X and Prewitt Y.

Scalable Network Dynamic Clamping using Extracellular Recording and FP-GAsJun Wen Luo, Terrence Mak, Peter Andras, Alex YakovlevRoom 2.20, Day 2, Time 3.15pmThis paper provides a novel hybrid neuronal-silicon network platform based on dynamicclamping technique. We employed the stomtograsic ganglion nervous (STG) and FPGAsfor biological part and artificial neuron implementation. Compare to the previous work,this system solve two important bottlenecks: the first one is that making the systemscalable; other one is enhance the computational ability and avoid jitter issue, they areall key aspects for design a close loop with biological system.

System Level Delay Modelling of Manufacturing Process VariationChenxi Ni, Gordon Russell, Alex BystrovRoom 2.20, Day 2, Time 3.30pmThe e!ect of manufacturing process variations has become a major issue in circuit delayverification, and will gain more importance in the future as device scaling continues inorder to satisfy market place demands for circuits with greater performance and func-tionality per unit area. This paper proposes a methodology to bring the process variatione!ect from transistor level up to system level in term of circuit delay under di!erentoperating conditions, i.e. input signal slope and output load. Using a first order canoni-cal gate delay model and block based statistical static timing analysis (SSTA) approach,a statistical cell library has been built which enables e"cient analysis of process varia-tion e!ect on system propagation delay with reduced computation time compared to theMonte Carlo simulation approach. As a demonstration vehicle for this technique, the de-lay distribution of a 2-state asynchronous micropipeline circuit has been simulated usingthis cell library. The experimental results show that the proposed method can preciselypredict the delay distribution with less than 5% error rate and at least 50,000 times fastercomputation time compare to 5000 sampled SPICE based Monte Carlo simulation data.

Hardware Implementation Verification of A Hybrid Power Delivery Unit forA Novel Task and Power Scheduling method for Asynchronous Loads in En-ergy Harvesting SystemsXuefu Zhang, Hock Low, Delong Shang, Fei Xia, Alex YakovlevRoom 2.20 , Day 2, Time 3.45pmIn energy harvesting systems, energy may be considered as infinite. However, powerfrom energy harvesting devices may be very limited and vary in a large range. Thereforehigh e"cient and intelligent power management methods are more and more demanded.On the other hand, asynchronous loads may have more potential for energy harvesting

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applications due to its low power and high voltage variation tolerance. Thus, in orderto investigate a novel task and power scheduling method for asynchronous loads in en-ergy harvesting systems. A hybrid power delivery unit is developed. This paper mainlypresents hardware implementation and verification of the hybrid power delivery structurebased on FPGA and PCB.

Improving the Robustness of Self-timed SRAM to Variable VddsAbdullah Baz, Delong Shang, Fei Xia, Alex Yakovlev, Alex BystrovRoom 2.20, Day 2, Time 4.00pmThe most e"cient power saving method in digital systems is to scale Vdd, owing to thequadratic dependence of dynamic power consumption. This requires memory workingunder a wide range of Vdds in terms of performance and power saving requirements. Aself-timed 6T SRAM was previously proposed, which adapts to the variable Vdd auto-matically. However due to leakage, the size of memory is restricted by process variations.This paper reports a new self-timed 10T SRAM cell with bit line keepers developed toimprove robustness in order to work in a wide range of Vdds down to 0.3V under PVTvariations. In addition, this paper briefly discusses the potential benefits of the self-timedSRAM for designing highly reliable systems and detecting the data retention voltage(DRV).

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Posters

Large-Scale Hybrid Bio-Electronic Networks for Next-Generation Brain-Ma-chine InterfaceGraeme Coapes, Terrence Mak, Alex YakovlevRoom 2.20, Day 2, Time 12noonNext-generation brain-machine interfaces will consist of bio-electronic hybrid networks,which will involve biological neurons being directly connected to artificial model neurons.Through this technology the functionality and behaviour of brain networks will be ableto be studied, restored and improved. The development of the technology will rely heav-ily upon the electronic design. Recent advancements in FPGA-designs are expected toprovide an excellent foundation for this. This poster illustrates the initial results thathave been gained from the development and evaluation of an electronic neuron model.The results of which provide the design constraints for the implementation of an op-timal FPGA-based neuron. This optimality considers both computational aspects andbiological realism.

Globally Asynchronous Elastic Logic Synthesis (GAELS)Johnson Fernandes, Alex Bystrov, Alex YakovlevRoom 2.20, Day 2, Time 12noonThis project aims to establish a pragmatic foundation of new methods and CAD tools tosupport design of digital systems with mixed synchronous-asynchronous architecture. Theprincipal approach Globally Asynchronous Elastic Logic Synthesis (GAELS) presents anovel GALS design that combines a globally asynchronous locally synchronous design withElastic Logic principles. The system would be partitioned into multi-block componentscalled localities with the help of Elastic Logic to optimise the partitions both function-ally and physically. The project will formalise new theoretical models and algorithmsfor dataflow representation of the Elastic GALS systems, automated partitioning of glob-ally clocked systems into locally synchronous islands, system elastisation, implementingasynchronous protocols and integration into an appropriate industrial CAD environment;thereby leading to the development of an EDA tool incorporating asynchronous designstrategies to solve the design issues in nanoscale technologies such as process variation,power dissipation, area and speed.

Acceleration of Complex Network AnalysisAthanasios Grivas, Terrence Mak, Alex YakovlevRoom 2.20, Day 2, Time 12noonThe scientific role of complex networks nowadays is of great importance. Their universalcharacteristics can be adopted for use from all over the scientific fields. This is the reasonthat scientists are pushing to the limits the network analysis. But the conduct of suchanalysis in CPU models it can be dramatically slow. They are not able to process multiplecomputations on a small time frame. There is need for acceleration of complex networkanalysis where the time execution of the used algorithms will be decreased in a large scale.Until now these algorithms were executed to conventional CPUs in sequential way. Thebreakthrough is the use of GPUs and parallel computing in order to accelerate the whole

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process. The CUDA (Compute Unified Device Architecture) architecture is used as themain tool in order to achieve this purpose. The transformation of common algorithmsas matrix multiplication to a parallel model has shown large acceleration, which is apromising point for the field of network analysis.

Spike Sorting DSP Device for an Implantable Biotelemetry SystemMauricio Gomez Segura, Graeme Chester, Je! NeashamRoom 2.20 , Day 2, Time 12.00noonImplantable biotelemetry systems for neural recording are an essential tool in studies ofthe function of the nervous system. Neuroscience research demands a large number ofsimultaneous channels, so there is a continuously need to increase the capacity of thesesystems. Implantable circuits must be small and operate at low power levels. Commu-nication bandwidth and power limitations require us to perform data reduction on-chipbefore transmission, and spike sorting is one way of accomplishing this. The work pro-posed for this project is the development and implementation of a digital signal processingdevice (DSP) for processing data from action potentials in neurons using a novel algorithmderived from existing multichannel spike sorting methods to obtain a better approach,especially in terms of features extraction. It is intended that the proposed device is inte-grated to an implantable biotelemetry system currently under development at the Schoolof EECE in the Newcastle University.

Development of a High-Rate Biomedical Telemetry Modulator Using Low-PowerDigital Techniques for Long-Term Indwelling Implants in Continuous Use.Minerva Marin Arteaga, Graeme Chester, Je! NeashamRoom 2.20 , Day 2, Time 12.00noonThe rapid advances in microelectronics have led to the interest in wireless telemetry.Long-term indwelling implants for the treatment of disease and injury to the nervous sys-tem are one of the applications of such systems. The design and implementation of thetransmitter for a biomedical implant must take into account the following constraints: lowsize, low power consumption, and high data rate. The transmitter should work at highdata rates because in neuroscience research it is necessary the use of many electrodes inorder to send a big amount of information simultaneously. The most promising approachfor the design of these devices is the UWB technology because of its advantages whichare simplicity, leading to both low power and low size, and high data rate capability. An-other important issue is the modulation scheme adopted since its purpose is to help thetransmitter not only to achieve a high data rate, but also to provide a stable performancein the human body channel. The main goal of this project is to develop a biomedicaltelemetry modulator capable of modulating the data at rates larger than 1.6 Mbps witha minimum of external components, and using low-power digital techniques.

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Power Electronics, Drive and Machines

Presentations

A High Torque Density, Direct Drive In-wheel Motor For Electric VehiclesChukwuma Ifedi, Glynn Atkinson, Barrie MecrowRoom 2.21, Day 2, Time 11amThe use of in-wheel motors as a source of propulsion for pure electric or hybrid electricvehicles (EV) has recently received a lot of attention. The drive environment has verystrict constraints on design such as compactness, high torque density and e"ciency, lowcogging and torque harmonics and must operate safely within the harsh environment.This paper examines the design options for a direct drive in-wheel motor with integratedpower electronics for use in passenger and light commercial vehicles. The choice of poleand slot number, ability to use saliency, and use of redundancy are all discussed. A seriesof prototype motor drives have been built and extensively tested on dynamometer testrigs and in a range of road vehicles: the paper presents test results on cogging, iron loss,winding factor, magnet demagnetisation and inductance for the d q axis obtained andcomments upon performance achieved, as the slot and pole number combinations arechanged.

Accurate Estimation of Electric Vehicle Speed using Kalman Filtering in thePresence of Parameter VariationsDavid Hodgson, Shady Gadoue, Barrie MecrowRoom 2.20, Day 2, Time 11.15amIndustrial electrical vehicles such as tow tractors and fork lift trucks require smoothprogressive acceleration and precise speed control, regardless of load changes and poormechanical drivetrain components such as gear backlash. During steady state constanttorque conditions the motor and vehicle speeds are the same, taking into account the gearratio and tyre radius. Whenever the motor torque or load on the vehicle changes, thespeeds are no longer equal due to the mechanical characteristics of the drivetrain. Thisa!ects both the vehicle speed feedback, which is only available from the motor encoder,and the smoothness of the vehicles response. This paper will present a vehicle speedestimation scheme that uses Kalman filtering. It is robst to significant changes in thevehicles mass through estimating this using a recursive least squares algorithm. Theestimated mass is then used to correct the Kalman filter vehicle speed estimator.

The Trouble with Eddy Currents: Minimising Rotor Loss in HSHP PM ma-chinesDaniel Smith, Dave Atkinson, Barrie MecrowRoom 2.21, Day 2, Time 11.30amHigh Speed High Power (HSHP) Permanent Magnet Synchronous Machines present par-ticular di"culties in thermal, mechanical and electromagnetic design. A particular ex-ample of these challenges is the minimisation of eddy current losses in the rotor magnets,which has implications for the thermal and mechanical design of the motors as well as the

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overall machine e"ciency. Further constraints are placed by the availability and limita-tions of the driving electronics and the materials used to manufacture the machine. Thispaper will discuss the various causes of these losses and the methods that exist to tryand minimise them. The unique challenges posed in applying the appropriate mitigationmethods to a 1.1MW high speed dynamometer under construction with an Industrialpartner, and the implications resulting from particular design choices, have led to a list ofrecommendations and design methodologies for future high speed high power PM motordesigns.

Three-phase Modulated Pole Machines Utilising Mutual Flux PathsJamie Washington, Glynn Atkinson, Dave Atkinson, Barrie MecrowRoom 2.21, Day 2, Time 11.45amThis paper discusses three phase topologies for Modulated Pole Machines. The authorintroduces a new three phase topology which takes advantage of mutual flux paths. Theresults obtained from two prototypes are a presented to verify the concept; the resultsshow the new Combined Phase machine could provide both performance and construc-tional benefits over prior Modulated Pole Machine topologies.

High Torque Density Permanent Magnet Machine Configuration for Electricvehicle ApplicationsYasser Alamoud, Glynn Atkinson, Barrie MecrowRoom 2.21, Day 2, Time 1.55pmThe paper will describe a new method of driving greater torques per unit volume frompermanent magnet machine configurations. The method involves changing the statortopologies in order to introduce a magnetic gear ratio into the torque equation. Twodesigns are developed and compared in detail to conventional brushless d.c. machines ofthe same dimensions, and in both cases substantial gains in output torque are indicatedwith the new configurations

Ultra Compact Switch-Mode Power Supplies for Consumer Electronic Prod-uctsDavid Grant, Dave Atkinson, Barrie MecrowRoom 2.21, Day 2, Time 2.10pmThe use of power hungry portable devices is becoming ever more prevalent, and as suchthere is a need to develop advanced power supply systems to support them. The maindriving factors are increased power density and e"ciency, along with reduced cost. Dueto the sheer quantity of consumer electronic products on the market, economies of scalenow allow for the production of advanced power supplies for minimal cost. Equally, in-expensive power electronics and microcontrollers are making the use of variable speeddrives possible in consumer products such as washing machines, refrigerators or vacuumcleaners. One of the key limiting factors in terms of the size and cost reduction of suchpower converters is the requirement for large DC link capacitors and EMI filter compo-nents. This paper provides an insight into the advantages of low DC link capacitance andthe challenges associated with it.

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Cost Functions in Space Vector ModulationDave Winterborne, Barrie Mecrow, Volker PickertRoom 2.21, Day 2, Time 2.25pmHybrid electric vehicles (HEVs) have an important role to play in the move towards moreenvironmentally friendly forms of transport. To ensure that HEVs represent a feasiblesolution to lower carbon emissions, the e"ciency of each component in the drivetrain iscrucial. Work is ongoing to improve the e"ciency of induction machine-based drives bydeveloping a new loss minimisation control scheme using a cost function. Integral to thisis the adaptation of the conventional space vector modulation approach to allow predicteddrive losses to influence the control. This paper presents a background to this task andwork to date, as well as possible directions for future development.

Use of Wavelets to Identify the Position of Short Duration, High FrequencyComponents in a Periodic SignalRichard Gibson, Volker Pickert, Matthew ArmstrongRoom 2.21, Day 2, Time 2.40pmThis paper describes novel application of the Wavelet Transform used to identify unwantedradio frequency (RF) components in a voltage or current signal from a variable speed drive(VSD). An introduction to the Wavelet Transform is presented and the benefits overShort Time Fourier Transform (STFT) are discussed. The Wavelet transform is used toshow the position in time of various frequency components and their magnitude. Thebandwidth of the chosen wavelet transform is evaluated for various pseudo-frequenciesand the possible uses of this in the time domain are compared to a band pass filter. Acriteria for choosing suitable mother wavelet based on its bandwidth has been presented.The impulse response for the narrow band filter defined in CISPR16 is given and theproblems associated with using this in the time domain are discussed. A discussion ofhow the RF components which give rise to the radiated emissions are presented.

Investigation into Loss of Mains Detection Tecniques for Distributed Gener-ationAndrew Watts, Matthew Armstrong, Dave AtkinsonRoom 2.21, Day 2, Time 3.15pmDistributed Generation (DG) is defined as smaller generation units located within thedistribution network that are not centrally planned by the utility company. Possible ben-efits gained by increasing the proportion of DG include the introduction of renewabletechnologies. DG units can operate connected to the grid or as a power island. Due toseveral drawbacks, most utilities stipulate that the DG unit must be disconnected fromthe network when a power island occurs. A maximum delay between the occurrence ofan island and the disconnection of the DG unit is set at 2 seconds by IEEE connectionstandards.This paper presents a laboratory setup that has been specifically designed toverify the adherence to grid connection standards. A unique simulation environment isintroduced in which real control code can be tested in conjunction with a power networkmodel. Multiple novel in-the-loop based LOM detection methods presented, analysed andcompared.

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A Carrier-based PWM Control Method for a Three-Phase Four-leg VoltageSouce InverterMin Zhang, David Atkinson, Matthew ArmstrongRoom 2.21 , Day 2, Time 3.30pmIn this paper, carrier-based PWM switching scheme and 3-Dimensional SVM switchingscheme for a three-phase four-leg voltage source inverter are compared and analyzed.For the carrier-based PWM method, a new Discontinuous PWM peculiar to 3-D SVM ispresented. It has been proved that the algorithm of the carrier-based PWM is simplifiedand will not be a computational burden to the Digital Signal Processor. Simulationresults show that with a newly-designed control loop for the system, simultaneous supplyof three-phase voltage can be obtained even when the load is unbalanced or/and nonlinear.

Implementation of a Non Zero Vector Space Vector Pulse Width ModulationUsing TMS320F28335 Microcontroller.Bassim Jassim, Bashar Zahawi, David AtkinsonRoom 2.21, Day 2, Time 3.45pmThis paper investigates the performance characteristics of a non zero vectors space vectorpulse width modulation (SVPWM) algorithm for three phase voltage source inverters.This method does not use any zero voltage vectors, hence it can reduce the commonmode voltage and the zero sequence circulating current (ZSCC) for parallel connectedvoltage source inverters. The proposed SVPWM is implemented using a TMS320F28335microcontroller and the practical results are compared to the conventional SVPWM.

Loss Minimization and Voltage Support for Distribution Network using Par-ticle Swarm Optimization TechniqueIdris Musa, Shady Gadoue, Basher ZahawiRoom 2.21 , Day 2, Time 4.00pmLoss reduction and voltage support are required for e"cient operation of Transmissionand Distribution (TD) networks. In this paper, Particle Swarm Optimization (PSO) isemployed to size and locate Distributed Generation (DG) in a distribution network. Un-like most previous studies, DG nodes are modeled as generator (PV) nodes in this study,to provide more e!ective loss reduction and voltage support. Three cases are considered.The first two involve the integration of one or two generators of optimal size and location,respectively, whereas the third involves the integration of a single generator of optimalsize at non optimal location. The study is carried out on the 16-bus radial distributionnetwork. The results show that DG is more e!ective in minimizing network power lossand providing ancillary service of voltage support, when modeled to inject real power andregulate the node voltage to which it is connected.

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Posters

Improvement of DFIGs for Wind Power SystemsZheng Tan, Basher Zahawi, Wenping CaoRoom 2.20, Day 2, Time 12noonIt has been well acknowledged that global warming and climate change is closely relatedto electricity generation from burning fossil fuels. As a result, to generate electrical powerfrom renewables, especially wind, is playing a key role in tackling these environmentalissues. For wind turbine applications, the current dominant machine technology is thedoubly fed induction generators (DFIGs). In the past, the study has generally focusedon the control of the DFIGs to provide the best overall performance. However, the powerloss mechanisms and energy e"ciency of the machines themselves have not yet fully un-derstood. This project looks into the loss components and their impacts on the overalle"ciency and power output by using analytical, numerical and experimental methodolo-gies and by taking account of specific location, wind speeds and load characteristics. TheDFIGs are also investigated within a wind power system so as to improve the power sys-tems fault tolerance (low-voltage fault-ride-through capability) and protection schemes.

VRSC Converters for Variable Voltage and Variable Frequency SupplyTahani Al-Mhana, Volker Pickert, Bashar ZahawiRoom 2.20, Day 2, Time 12noonThe research project develops a standard variable reactance series capacitor (VRSC)converter that can be applied to a variety of applications such as renewable energy, powergrid and stand alone systems. VRSCs are not new and they are well known as a tool toenhance power factor, increase e"ciency and reduce harmonics. However, a wide spread ofVRSC is so far limited due to high developing and manufacturing cost of these converters.So far di!erent VRSC converters have been applied to di!erent applications and althoughin principal each of them could be applied to any application a standard VRSC has notbeen developed yet. This research project will therefore develop a standard VRSC circuitthat can be applied to a large range of applications. The challenge of the project is todesign a VRSC circuit that operates with a large supply frequency spectrum and a largesupply voltage range. Beside the selection of the right converter topology the focus ofthe work is the development of a control algorithm that is flexible enough to cope withfrequency and voltage changes. Data handling and measurement of frequency, voltageand current in a noisy environment are some of the hurdles that will be investigated.In a later state of the project AC capacitors, currently used in VRSCs, will be replacedwith DC capacitors and the diode bridge rectifier will be replaced with PWM controlledrectifier in order to investigate the benefits of these changes.

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Sensorless Control of DFIG Based Wind TurbineAmer Kareem, Bashar Zahawi, Shady GadoueRoom 2.20, Day 2, Time 12noonWind power conversions systems (WPCS) are the fastest growing and most promisingrenewable energy source due to it become competitive commercially in parallel withslightly increase in size of turbine installations. The e"ciency of the WPCS can begreatly improved using an appropriate control algorithm especially by reducing the costand maintenance. This study presents a rotor position estimation algorithm for the vec-tor control of a doubly-fed induction generator (DFIG) in a variable speed wind turbinesystem. The investigation deals with modelling the aerodynamic, driven train, generatorand the bi-directional power converters models with the vector control (VC) applied onthe RSC and GSC converters, and the impact of variable speed wind turbines on thepower system. The control scheme uses stator flux-oriented control for the rotor sideconverter bridge control and grid voltage vector control for the GSC bridge control. Themain configuration of the DFIG based wind turbine has been reported with preparationto the behaviour analysis of the system control with and without position encoder thatrequired in the control. The comparison of simulation results highlights to the superiorperformance of the proposed method.

Reluctance Machines for Traction ApplicationsChristopher Spargo, Dave Atkinson, Barrie MecrowRoom 2.20, Day 2, Time 12noonTypical traction drives currently use electrical machines which incorporate permanentmagnets fashioned from large amounts of rare earth material. As the demand for pureelectric (PEVs) and hybrid electric vehicles (HEVs) increases, the demand for these rareearth materials also increases. With unstable market prices, associated environmentalissues and global supply problems of rare earth elements, an alternative form of trac-tion motor must be considered in order to meet the cost and performance demands offuture traction applications. Reluctance principle based machines are an ideal candidate.If we can reduce the amount of rare earth material required whilst maintaining com-petitive traction performance, we can reduce the cost of traction drives, reduce naturalresource demand, and combat environmental and global warming issues, whilst meetingthe demand for the future electric vehicle market. This research project is concernedwith the development of traction motors with low/no rare earth material requirementsby developing competitive reluctance machine drives for future HEV and PEVs.

Transient Performance of an Isolated Induction Generator under Symmetri-cal and Unsymmetrical faultsAbdlrhman Alfrhan, Wenping Cao, Basher ZahawiRoom 2.20, Day 2, Time 12noonIn recent years, there has been immense concern about environmental issues due to theuse of fossil fuels. As a result, research e!orts have been focused on renewable energy.Induction generators are widely used in renewable energy sources because of their sim-plicity, robustness and low cost. However, there are some drawbacks associated with theuse of this type of generator. One of the major problems facing the self-excited inductiongenerator, whether it is grid-connected or isolated from the grid is its dynamic response to

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sudden external transients, such as faults or a sudden change in load. In this project, thebehavior of stand-alone self-excited induction generator (SEIG) following di!erent sym-metrical and unsymmetrical fault such as single line-to-ground fault, double line fault,and double line to-ground fault will be investigated. In addition, sudden change in load(including unbalanced load conditions) will be investigated taking into account the mag-netic saturation. A mathematical model (d-q model) will be used in order to simulate theperformance of the system under study. Results obtained by simulation will be analyzedand verified experimentally.

Maximised Torque and Minimised Magnet Use in Electrical Machines forAutomotive ApplicationsRoziah Aziz, Wenping Cao, Dave AtkinsonRoom 2.20, Day 2, Time 12noonDue to concerns over global warming and greenhouse gas emissions, research on electricalvehicles (EVs) has become popular. The most successfully developed drives to fulfil thespecial requirement for electric vehicles include Permanent Magnet Synchronous Motor(PMSMs) which has characteristics of high power density and high starting torque andthe Switched Reluctance Motor (SRMs) which is a more simple construction, with lowermanufacturing costs. However, there are some technical challenges needed to overcometo meet the EVs specifications. The purpose of this research is to design and develop acombination of Switch Reluctance Motor (SRMs) and Permanent-Magnet SynchronousMotor (PMSMs) in order to produce a drive with maximum torque and minimum magnet.There are three di!erent magnets such as ferrite, Neodymium-Iron Boron and SamariumCobalt will be used and tested in order to find the best solution for the drive designed.To achieve the goal, design will be done on new motor topology of combining SRMs andPMSMs by using Finite Element numerical software. After meeting specifications needed,several experiments with di!erent magnets will be conducted to validate the results andsome analyse will be made on them.

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