These are the slide I used to present my thesis. The following is the abstract from my thesis: Atacama Large Millimeter/submillimeter Array, or ALMA, is a multinational project which will be composed of around~66 radio-telescope antennas, that have to be coordinated. Observation time on this very expensive facility has to be carefully planned, allowing to use the available time efficiently for observation, reconfiguration, and maintenance. To reach this goal, ALMA project must count with a simulation tool to allow proper study of the scheduling behaviour and configuration of the array of antennas. There are several factors that have to be included in the simulation environment, such as environmental variables, array disposition, incremental addition of antennas, failures of antennas, self-shadowing, etc. This undergraduated thesis cover the analysis and development of the planning mode simulator for the ALMA project. A new architecture to achieve the requirements is proposed, and a first versión is successfully developed by the scheduling subsystem team. The new architecture will be re-used for the re-factoring of the scheduling subsystem.
- 1. Planning Mode Simulator: A simulation tool forstudying ALMAs
scheduling behavior Undergraduate thesis presentation Arturo A.
Hoffstadt Urrutia Software developer,
www.almaobservatory.orgResearch collaborator, www.utfsm.cl
2. Agenda Introduction: ALMA, Radio-astronomy, Interferometry,
SchedulingSubsystem State of Art and Practice Site
characterization, scheduling simulations, Analysis Architecture
Desing and Construction Conclusions 3. IntroductionALMA antenna in
a starry night, long exposure. 4. Atacama Large Millimeter Array
12m Array Simulation (!) Atacama Compact Array (ACA) 5. Operation
Site Facility 6. ALMA Operation Site 7. Radioastronomy Area that
studies radio waves emissions fromphenomena occurring in the outer
space. Phenomena: Electrons transitions. Molecular vibrations.
Molecular rotations. Black body radiation in the order of 1 [K]
temperature. Synchrotron radiation. Dark matter. 8. Interferometry
Smaller wavelenghts => larger antennas. Either build bigger
telescope, or use interferometry. = D Technique that allows to
combine several sampling ofthe same source, to enhance image
resolution. Spatial resolution is limited by diffraction effects:
9. Interferometry This technique combines the signal received from
two receptors, multiplying and averaging their signals. 10.
Interferometry The two receptors, as seen from the observing source
POV, form a baseline. More than one baseline can be combined to
reconstruct the original signal. Baselines changes as earth
rotates. 11. Scheduling Subsystem Purpose: ... to manage the
execution of approvedobserving projects. Input: Observing projects,
Array and DSAconfiguration. Output: Observation schedule. (!)
Please note that this is a huge simplification of thesystem.
Observing projects are composed of severalScheduling Blocks (SBs)
12. Scheduling Subsystem To construct this observation schedule,
the subsystemmust count with several data: Wind speed and
direction. Water vapor content. Available antennas and equipment.
ALMA array configurations. Array baselines. UV coverage.
Visibility. Percentage per executive, and so on... 13. Problem
Definition Planning Mode Simulator is one of the deliverables ofthe
Scheduling subsystem. There is a basic implementation for it, but
afteranalysis, found it to be non-usable as it is. The current
solution has scalabitlity and maintenanceissues. But, simulations
concepts and code can be reused. 14. Thesis ProposalMain Goal: To
design and develop the first iteration of the Planning Mode
Simulator for the scheduling subsystem of the ALMA Project. 15.
Thesis Proposal Specific Goals: Integration of the student to the
ALMA Project and itsstandards. Define a software development
project. Refine necessary requirements.Define an
interactionstoryboard and GUI. Design the Planning Mode Simulator.
Define data models for input and output data. 16. State of Art
andPractice 17. Site Characterization AOS has several studies,
which shows: Instrument that can determine precepitable
watervapour, temperature, visibility, wind, phase stability, etc.
This data has been characterized through severalyears. Long lasting
weather effect are studied, such as globalwarming, El Nio/La Nia
cycles, and Bolivian winter. Studies on wind, temperature and other
weathervariables according to geographic environment is
alsoavailable. 18. Radio InterferometerScheduling Simulation ALMA
publications of earlier development in simulatoran DSA by Farris.
ALMA scheduling policies addition to schedulingsubsystem by Lucero.
One research group [5], but no publications or publicwork. 19.
Scheduling Subsystem On previous design, which was published in
[6]: Only considers ALMA configuration and observationproject as
inputs. Simplistic weather simulation. No presented results.
Requirements for the Planning Mode Simulator can befound in several
documents. A refined version, with cross-reference, was created.
20. AnalysisMilky Way blazes facilities at Mount Paranal. 21.
General Requirements Create a software that allows the study of:
Scheduling algorithms, Configuration of ALMA for the observing
season Distribution of observing projects. Weather simulations
Randomization and fuzzy denomintations Configuration of ALMA.
Specially growing behaivour. 22. Input and Parameters Requirements
Observation projects for a whole season (12 months,18000 scheduling
blocks). Changes in scientific rating of projects. Tuning
parameters of scheduling algorithm. Consider ALMA evolution over
season. Consider executive percentage balancing guidelines.
Historical weather data. 23. Reports and visualizations
requirements Prepare a long series of reports and visualization:
Observing modes over/under subscriptions Observing band over/under
subscriptions. Allocated time per executive. Expected hours of
observing as a function of: Time Configuration evolution And much
more... 24. Simulations inputs and parameters requirements Present
data: Absent data: Observation projects. Weather. Actual array
Executive.configuration. ACA coordination. Calibrators. Sub
arraying. Estimated time of Future arrayexecution.configuration.
25. Architecture 26. Transveral concerns Performance, specially in
network communications. Software maintenance. Flexible DSA. Several
input methods. 27. Dynamic Scheduling Algorithm Inversion of
control architecture pattern as main driver. Four levels of
independant class famalies. Each level has a very determined
concern and interface(uncoupling). Pieces in each level can be
interchanged, or multipleinstances can be used. All these to
control the scheduling blocks flow throughselection, priorization
and execution stages. 28. Planning Mode Simulator Conceived as a
library, with a CLI and GUI. All parameters and input data are
transfered to acommon package, so that can be reused. Simulation
logic is delegated to data-model ofobservatory characterics. Time
management is handled by the program. Arrays and starting and
ending times are expressed indata-models. Necessary configurations
are taken from an XML-file. 29. Data access and persistance Initial
data population: XML files. Data persistance: ORM solution. For
each database, a common object oriented data-model is used, and
from it: An XML Schema Definition (XSD) is generated. POJO classes
for in-memory representation of ORMare generated. 30. Data access
and persistance A broker-like design pattern will be used
forimplementing intelligent cache of the ALMA Archive ina
primary-memory HSQLDB. Eliminates most queries currently directed
to Archive. A primary-memory cache is far more efficient
thannetwork access or secondary memory. DAOs for accessing data. If
needed, conversion fromXML unmarshalled classes to ORM POJO classes
isprovided. 31. Conclusions and Future WorkHorsehead nebula, using
the 0.9-meter telescope on Kitt Peak. 32. Conclusions First
iteration is ready, and delivered to client. A new performance
oriented architecture has beencreated, and will be re-used for
scheduling subsystemas a whole. ALMA-UTFSM is researching new
algorithms, whichwill be tested using this same tool. Thesis done
as part of ALMA scheduling subsystem, infact, UTFSM contributing
0.5 FTE to the project. 33. Conclusions More parameters and
functionality to be added in nextiterations. Computer simulated
weather, SB linkage, sub-arraying,calibrations, ... GUI to be
provided in coming iteration as anOpenOffice application, with
planning mode simulatorincorporated as plugin, using UNO component
model. To achieve the necessary visualization capabilities. 34.
Bibliography Site characterization: Alma memos series [1] M.
Holdaway, Fast switching Phase Calibration... [25] J. Prez,
Analysis of wind data gathered at Chajnantor. S. Radford, Site
Characterization and Monitoring. [35] Radio astronomy and
Inteferometry: K. Jansky, Radiowaves from outside the solar system.
B. Burke, An introduction to radio astronomy. [11] W. Goss,
Discovery of Type I, II and III ... [21] Patterns: R. Johnson,
Designing resusable classes. [27] State before this thesis: Allen
Farris et. al, Scheduling Subsystem Design Document. [17] 35.
Acknowledgement To my family, who has accompany my along this road.
To my dear friends, who are almost my second family. To two dear
teachers, Cecilia Reyes and Horst vonBrand. To my collegues, who
are as much author of this workas I am: Jorge, Rafael and David.
This work is possible through the ALMA-Conicyt grant#31080031, and
a complementary fund granted byNRAO. 36. Questions? 37. Use cases
(1/3) 38. Use cases (2/3) 39. Use case (3/3)
