centre for modeling and control of complex systems · 2005-04-06 · the centre for modeling and...

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CENTRE FOR MODELING

AND CONTROL OF

COMPLEX SYSTEMS

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CENTRE FOR MODELING ANDCONTROL OF COMPLEX SYSTEMS

Introduction

The Centre for Modeling and Control of Complex Systems (CMCCS) was established in 2003 to champion R&D activitiesrelated to the understanding of dynamics and computational issues of complex systems. It is an inter-divisional researchcentre with active participation of researchers from various research institutions in Singapore. The mission of CMCCS isto excel in research and development in the methodologies for modeling, computation, control and optimisation ofcomplex systems. Its core research activities include Modeling and Control of Biological Systems, Computational Nano-Electronics, Computational Electromagnetics, Control of Networks, and Modeling, Optimization and Control Techniques.

2004 was a fruitful and eventful year for CMCCS. A number of new results and applications were established. Majorachievements include the following:

• Total research grant of about S$4 million from various sources• Publication of 84 papers in renowned international journals• Presentation of 29 papers at international conferences• Publication of one book in Springer-Verlag and three book chapters• Filing of two US patents

MODELING AND CONTROL BIOLOGICAL SYSTEMS

Objectives

In line with nationwide efforts towards research into thelife sciences, this research programme focuses on exploringboth the fundamental and applied aspects of biological andbiomedical systems, with particular emphasis on extendingsuch research and development work to practicalapplications and implementations in health care, such asclinical diagnostics, automation and treatment.

Highlights of Research Activities

Models of the tumor microvasculature can provide medicalresearchers with a means to better understand and analyzethe processes associated with tumor formation andprogression. Such models can be used in conjunction withdynamic functional imaging methods for diagnostic andprognostic purposes. Recently, researchers in the group havedeveloped new models of the tumor microvasculature thatare physiologically more realistic and which yield additionalparameters that are clinically useful. These includeparameters for vascular dispersion and capillary-tissueextraction. Collaborative studies with the NationalNeuroscience Institute have been carried out on braintumors using Computed Tomography. Initial results showthat certain specific brain tumor types can be distinguishedfrom normal tissues based on a combination of these

parameters. Parts of these results have been accepted forpublication in ‘Radiology’, a leading international journalon medical/clinical imaging. The paper was also selectedby the Editor of ‘Radiology’ to be featured in their “Scienceto Practice” section where the science and practiceimplications of original research are further explained. Theseachievements have strengthened the confidence of ourclinical counterparts in their collaboration with our centre.More clinical tests and studies are ongoing. Further researchareas that can be explored are the implementation of thesemodels on other imaging modalities such as MagneticResonance Imaging.

On the modeling and control of drug infusion, an ongoingproject is undertaken with the aim to control the infusionrate of drugs that can reduce the blood pressure of patients.In this project, an adaptive PID control system, fuzzy logiccontroller, and MPC control for the mean arterial pressurecontrol have been designed. For clinical trials, thedeveloped control systems have been implemented andclinical testing is being carried out. Research work has alsobeen carried out in the neuronal control of leg movementsfor patients with spinal injury with the aim to developcomputer control models for the planar multi-joint legmovements based on the currently accepted theories andhypothesis in biological motor control and controlengineering.

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The Electroencephalogram (EEG) is a record of electricalfluctuations induced at the scalp due to activities of neuronsin the brain. It is recognized that the EEG changes as thebrain engages in various activities. EEG research seeksmostly to understand the dynamic processes in the brainthat are the basis of physical and mental behavior.Researchers are studying possible characteristics andchanges in the EEG associated with different mental (i.e.cognitive and motor) tasks and design efficient neuralclassifiers which can recognize various mental tasks fromthe EEG signals. The potential application is in the area ofBrain Computer Interface.

Members of the group are also researching methods toimprove the quality of medical imaging. A concern withthe use of Computerized Tomography (CT) imaging is theamount of X-ray doses during scanning. With the objectiveof reducing X-ray exposure, new image reconstructionalgorithms for spiral CT and for local CT with reducedartifacts and computational load and improved imagequality have been developed. On the reduction of specklesin ultrasound imaging, both theoretical and experimentalinvestigations have been carried out. In contrast to theexisting algorithms which process ultrasound envelopeimages and have difficulties in separating the tissueinformation from speckles, the novel approach proposedapplies multidimensional and optimal deconvolution andmultiresolution decomposition techniques to radiofrequency echo signal processing for speckles separationand reduction.

Experimental Ultrasound Signals

Modeling and Control of Planar Multi-joint Leg Movements

Modeling of the Tumor Microvasculature

Asst Prof Koh Tong SanProgram [email protected]

Staff Members

Asst Prof Mao Kezhi Assoc Prof Zhu Kuanyi Assoc Prof Zhang Cishen

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Prof Soh Yeng Chai Assoc Prof Wong Jia Yiing,Patricia

Assoc Prof Song Qing Assoc Prof ParamasivanSaratchandran

Ongoing Research Projects

Project Title Principal Investigator Funding

In-Vivo Assessment of Neo-Angiogenesis and Microcirculatory Koh Tong San BMRC ($158.5k)Characteristics of Breast Carcinoma using DynamicContrast-Enhanced Magnetic Resonance Imaging withCorrelations to Histopathology

Research Projects Completed in 2004


Development of Algorithms for High-Performance Digital Zhang Cishen NTU ($96.83k)Image Processing with Applications to Medical Imaging

Design of computerized drug delivery control system Zhu Kuanyi NTU ($55.8k)

Selected Publications in 2004

1. D.G. Zhang, K.Y. Zhu, and H. Zheng, “Model the leg cyclingmovements with neural oscillator”, Proc. IEEE InternationalConference on Systems, Man and Cybernetics, Holland, Oct. 2004.

2. D.G. Zhang, and K.Y. Zhu, “A structured neural network controlsystem for FES cycling”, Proc. 9th Annual Conference of InternationalFES Society, U.K., Sept. 2004.

3. D.G. Zhang, and K.Y. Zhu, “Simulation study of FES-Assisted standingup with neural network control”, Proc. 26th Annual InternationalConference of the IEEE Engineering in Medicine and Biology Society,U.S.A., Sept. 2004.

4. D.L.H. Cheong, T.C.C. Lim, and T.S. Koh, “Dynamic contrast-enhanced CT imaging of intracranial meningioma: a comparison ofdistributed and compartmental tracer-kinetic models – initial results”,accepted, Radiology, 2004.

5. W. Cao, and Y.C. Soh, “Nonlinear multi-rate current state estimation:Convergence analysis and application to biological systems”,Computers and Chemical Engineering, Vol. 24, pp. 1623-1633, 2004.

6. K.C. Veluvolu, Y.C. Soh, and W. Cao, “Discrete-Time Sliding ModeObserver Design for a Class of Uncertain Nonlinear Systems withApplication to Bioprocess”, Proc. 8th International Conference onControl, Automation, Robotics and Vision, ICARCV’04, China, 2004.

7. X.N. Diao, and K.Z. Mao, “Clustering based watershed segmentationfor two-dimensional gel electrophoresis image”, Proc. FirstInternational BioEngineering Conference, Singapore, Sept. 2004.

8. A.Z. Cao, and Q. Song, “Breast mass segmentation on digitalmammograms by a combined deterministic annealing method”, Proc.IEEE International Symposium on Biomedical Imaging: From Nanoto Macro, USA, April 2004.

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COMPUTATIONAL NANO-ELECTRONICS

Objective

The objective of this research programme is to establish acoordinated research effort in computationalnanoelectronics among the local universities and researchinstitutes/centres. The main objectives are to develop anddeploy the infrastructure in computational nanoelectronicsfor the local/global researchers and industries, and toprovide education and manpower training in the emergingfield of nanoscale device modeling. The efforts on nano-computation and atomic modeling will drive new conceptsthat help turn the promise of nanoscience into newnanotechnologies.

The Computational Nano-Electronics Group (CNEG) is aninterdisciplinary group with a computational commonality.The CNEG current research is focusing on three areas:• LDPC : Low-dimensional physics and chemistry• NMNO : Nano-materials and nano-optoelectronics• NTND : Nano-technology and nano-devicesFor more details, please visit our website:http://www.ntu.edu.sg/eee/eee6/CNEI/


The activities of the group include the following:• Intense beam-nanostructure interaction• Transport in nanoscaled structure & quantum dots• Semiconductor nanocrystals for novel applications• Band structures of quantum wells and quantum dots• SiC device design, simulation, fabrication &

characterization• Nanosolid: functional materials design &

characterization• Photonic bandgap materials – ZnO thin film UV lasers• Nanoscale CMOS technology/device modeling

The research into interaction of electron beam and opticallight in nano-scale structures involves both numerical andanalytical derivation of the quantum scaling of Child-Langmuir law in the nanometer regime. This research willbe highlighted in an upcoming issue of X-Window, anewsletter published by the Applied Physics Division fromLos Alamos National Laboratory. Recently a universal multi-dimensional Child-Langmuir law was also completed forclassical, relativistic and quantum regime.

The nanosolid metrology research aims for functionalmaterials design & characterization to refine the “bondorder-length-strength” correlation mechanism forcontrollable growth of nanosolid with designed properties

for device applications. The research has resulted in 8 highimpact-factor (>3) papers with more than 50 citation hitssince Jan 2004.

Empirical Pseudopotential Method (EPM) has been used tocalculate band structure parameters of ZnO and MgO. Theband structure, form factor, electron and hole effectivemasses are obtained, from which the band structure andoptical properties of ZnO/ZnMgO QW can be investigatedusing 6-band and 8-band k∑p method. Our GaN and AlNband diagrams calculated by EPM have been requested tobe published in “Handbook on Physical Properties ofSemiconductors – III-V Compound”, Kluwer, 2004 by SadaoAdachi. Our GaN related papers have been cited over 110times so far.

Both experiments and modeling are carried out toinvestigate the mechanisms of DC and AC negative biastemperature instability (NBTI) for various sub-100nmtechnology generations. Si nanocrystals embedded in SiO2

Simulation of high current field emission from carbon nanotubes.

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films are synthesized and Si nanocrystal-based Er-dopedlight-emitting devices are fabricated with a CMOS-compatible process. Optical and optoelectronic propertiesare also investigated. We have observed some novelmemory effects such as capacitance/conductancemodulation and capacitance/current switching in MOSdevice structures containing Si nanocrystals. We areexploring the possibility of the application of the discoveriesin few-electrons (or even single-electron) memory devices.

The research in next-generation CMOS compact modelinghas received recognition with funding from SemiconductorResearch Corp (SRC), the world premier university fundingagency, with support from Chartered. The project is directedtowards the development of a predictive compact modelthat has minimum parameters and measurement data

requirement, a methodology to correlate compact modelparameters to process variations, and a framework forpredicting next generation CMOS technologies.

In addition to the respective research activities, CNEGmembers are actively involved in various collaborations,including invited visits to Los Alamos National Laboratoryand collaboration in the Thematic Strategic ResearchProgramme (TSRP) on Nanomanufacturing (with IME). TheGroup and its members are also active in inviting outsidespeakers, in organizing international workshops includingthe 4th Workshop and IEEE EDS Mini-colloquium onNAnometer CMOS Technology (WIMNACT-Singapore) andthe 3rd Workshop on Compact Modeling (WCM) in Boston,as well as in various organizing committees in internationalconferences.

Staff Members

Assoc Prof Zhou XingProgram Director

[email protected]

Asst Prof Ang Lay Kee,Ricky

Assoc Prof Au Yeung TinCheung

Assoc Prof Chen Tupei Asst Prof Fan Weijun

Assoc Prof Rusli Assoc Prof Sun Changqing Assoc Prof Yu Siu Fung Dr Gao FeiResearch Fellow

Dr Valeri LigatchevResearch Fellow

Dr Shangguan WangzuoResearch Fellow

Mr Xia JinghuaResearch Associate

Mr Chiah Siau BenProject Officer

Mr Liu YangProject Officer

Mr See Guan HueiProject Officer

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Development of Core Competence in Silicon Carbide Rusli A*STAR ($744,810)Technologies for High Temperature, High Power and HighFrequency Electronic Devices and Systems

Quantum Confined Zinc Oxide Thin Film for UV Lasers Yu Siu Fung A*STAR ($344,040)Applications

Technology-Based Predictive Compact Model Development Zhou Xing SRC (US$140k)for Next Generation CMOS

Multi-Level Modeling of Nanometer CMOS ULSI Systems Zhou Xing RGM ($200k)



Modeling of Broadband Compact Vacuum Power Devices and Ang Lay Kee, Ricky NTU ($78k)Vacuum Nano-electronics

Nanofabrication of magnetic thin films for high-density data Sun Chang Qing NTU ($66k)storage applications

MEng and PhD Theses Completed in 2004

Project Title Degree Student Supervisor(s)

Atomic modeling of negative bias temperature instability in PhD Tan Shyue Seng Chen Tupeiultra-thin gate dielectrics

Characterization of silicon nanocrystals embedded in SiO2 matrix PhD Liu Yang Chen Tupei

Optical and dielectric properties of nanosolid silicon PhD Pan Likun Sun Chang Qing

Size and nitrogen catalytic effects on the Magnetic Properties of PhD Zhong Weihua Sun Chang QingFe thin films

Workshops

Name(s) of Instructor(s) Title of Workshop Workshop Conducted for

Yang Cary, Kuo James, Workshop and IEEE EDS Mini-colloquium on IEEE Rel/CPMT/ED SingaporeLiou Juin, Cheng Yuhua, Nanometer CMOS Technology ChapterZhou Xing

Seminars

Name(s) of Speaker(s) Title of Seminar Affiliation

Ang Lay Kee Unified Three-Dimensional Child-Langmuir Law EEE

Sun Chang Qing O, N, C Chemistry Nanosolid Physics and EEENanometrology

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Seminars


Liou Juin Characterization and Simulation of Reliability of University of Central FloridaMOS Devices and ICs

Bera Lakshmi Strained-Si MOSFETS and High-K Gate Dielectrics for IMEAdvanced CMOS Applications

Pelloie Luc SOI CMOS Technologies: An Overview SOISIC

Sarkar Chandan Gate Oxide Degradation in MOS Devices Under High Jadavpur University, IndiaField Stress – Breakdown Issues and the Model

Voldman Steven ESD and Latchup in RF CMOS and RF BiCMOS Silicon IBMGermanium Technology

Lundstrom Mark The Transistor: from Lilienfeld to Landauer Purdue University, USA

Zhou Xing Unified Regional Approach to Consistent and NTUSymmetric DC/AC Modeling of Deep-SubmicronMOSFETs

Yu Zhiping Quantum Mechanical Carrier Transport and Nano-scale Institute of Microelectronics,MOS Modeling Tsinghua University

Xia Jian-Bai Electronic Structure and Optical Property of Institute of Semiconductors,Semiconductor Nanocrystallites Chinese Academy of Sciences

Benistant Francis Overview of Technology-Computer-Aided-Design PDF Solutions(TCAD) Simulations

Arora Vijay Quantum Engineering of Nanoelectronic Devices Wilkes University, USA


1. L.K. Ang, Y.Y. Lau, and T.J.T. Kwan, “Simple derivation of quantumscaling in Child-Langmuir law”, IEEE Trans. Plasma Sci.., Vol. 32,pp.410, 2004.

2. L.K. Ang, and W.S. Koh, “3D Model of Child-Langmuir Law”, Proc.31th IEEE International Conference on Plasma Science, 2004.

3. W.S. Koh, and L.K. Ang, “Simulation of high current field emissionfrom vertically well-aligned metallic carbon nanotubes”, accepted,International Journal of Nanoscience, Aug. 2004.

4. S.S. Tan, T.P. Chen, J.M. Soon, K.P. Loh, C.H. Ang, and L. Chan.“Atomic modeling of nitrogen neighboring effect on negative biastemperature instability of pMOSFETs”, IEEE Electron Device Lett.,Vol. 25, No. 7, pp.504-506, July 2004.

5. T.P. Chen, Y. Liu, M.S. Tse, S. Fung, and D. Gui, “Optical-ConstantsProfiling of SiO2 Thin Films Containing Si Nanocrystals”, J. Appl.Phys. Vol. 95, No. 12, pp.8481-8483, June 2004.

6. Y. Liu, T.P. Chen, C.Y. Ng, M.S. Tse, S. Fung, Y.C. Liu, S. Li, and P.Zhao, “Influence of charge trapping in Si nanocrystals embeddedthroughout the gate oxide in MOS structures on I-V and C-Vcharacteristics”, Electrochemical and Solid-State Lett., Vol. 7 , No.7, pp. G134-G137, April 2004.

7. W.J. Fan, and J.B. Xia, “Energy band and effective mass parametersof wurtzite ZnO”, Proc. International Conference Optics & Photonicsin Technology Frontier, July 2004.

8. C.H. Gao, H.Y. Ong, W.J. Fan , and S.F. Yoon, “Analysis of opticalgain and threshold current density of 980 nm InGaAs/GaAscompressively strained quantum well lasers”, ComputationalMaterials Science, Vol. 30, pp.296-302, 2004.

9. M.R. Wang, Rusli, J.L. Xie, N. Babu, K. Rakesh, C. Y. Li, “Study ofoxygen influences on carbon doped silicon oxide low k thin filmsdeposited by plasma enhanced chemical vapor deposition”, J. Appl.Phys., Vol. 95, No. 13, 2004.

10. M.R. Wang, Rusli, M.B. Yu, N. Babu, K. Rakesh, and C.Y. Li, “Lowdielectric constant films prepared by plasma enhanced chemicalvapor deposition from trimethylsilane”, accepted, Thin Solid Films,2004.

11. C.L. Zhu, Rusli, C.C. Tin, S.F. Yoon, and J. Ahn, “Drain-Induced BarrierLowering Effect and Its Dependence on the Channel Doping in 4H-SiC MESFETs”, Proc. 7th International Conference on Solid-State andIntegrated-Circuit Technology, 2004.

12. C.Q. Sun, C. Li, S. Li, and B.K. Tay, “Breaking limit of atomic distancein the monatomic chain”, Phys. Rev. B 67, pp.245402, 2004.

13. C.Q. Sun, “Surface and Nanosolid Core-level Shift: Impact of AtomicCoordination Number Imperfection”, Phys. Rev. B 69, pp.045105,2004.

14. C.Q. Sun, W.H. Zhong, S. Li, and B.K. Tay, “Coordination imperfectionsuppressed phase stability of ferromagnetic, ferroelectric, andsuperconductive nanosolids”, J. Phys. Chem. B108, pp.1080-4, 2004.

15. X. Zhou, S.B. Chiah, and K.Y. Lim, “A compact deep-submicronMOSFET gds model including hot-electron and thermoelectric effects”,accepted, Solid-State Electron., 2004.

16. S.B. Chiah, X. Zhou, K.Y. Lim, L. Chan, and S. Chu, “Source-DrainSymmetry in Unified Regional MOSFET Model”, IEEE Electron DeviceLett., Vol. 25, No. 5, pp.311-313, May 2004.

17. X. Zhou, S.B. Chiah, K. Chandrasekaran, K.Y. Lim, L. Chan, and S.Chu, “Unified Regional Approach to Consistent and Symmetric DC/AC Modeling of Deep-Submicron MOSFETs”, invited paper, Proc.7th International Conference on Modeling and Simulation ofMicrosystems, USA, Mar. 2004.

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COMPUTATIONAL ELECTROMAGNETICS (CEM)

Objective

This Research Programme aims to develop and applyefficient and accurate numerical techniques and tools forpredicting complex electromagnetic phenomena inengineering.

A fundamental understanding of these phenomena is criticalin the design and analysis of microwave, optoelectronic,microelectronic, and nanoelectronic devices for a very widerange of applications.

Highlights of Research Activities.The CEM programme encompasses both numericaltechniques and applications for the development ofelectromagnetic analysis and design tools as well asfundamental study of electromagnetic phenomena.

Our research activities include development andapplication of various numerical techniques, such asmethod of moments (MoM), finite element method (FEM),boundary element method (BEM), finite difference timedomain (FDTD) method, mode-expansion method (MEM),dyadic Green’s functions (DGF), and Ray Tracing method.Engineering applications cover a diversified area includingantennas, microwave filters, electromagnetic bandgapstructures, frequency selected surface, photonic crystalfibres, microwave / optical packaging, microwave imaging,electromagnetic compatibility, radio wave propagation,prediction of mobile phone radiation and effect in humanbody.

NTU-IHPC MoUThe Institute of High Performance Computing (IHPC) andNanyang Technological University (NTU), signed an MOUin 2002 to establish a joint Programme for Electromagnetics(PEM) to embark on research in computationalelectromagnetics.

During the first stage of three years, PEM will focus on threeprojects: (1) evolutionary computation for electromagnetics;(2) electromagnetic modeling of broadband packages foroptical communications; and (3) investigating on-wafercoupling and cross-talk effects of CMOS RF ICs.

Singapore Millennium Foundation AwardA notable delightful event is that Dr Tong Ming Sze receivedthe Singapore Millennium Foundation (SMF) ResearchFellowship Award from Singapore Technologies. His award-winning project is “Applications of Pseudo-Spectral TimeDomain (PSTD) Method for Studies of Periodical Structuresin Microwave and Optoelectronics.

Electromagnetic Modeling of Broad-Band Packages for OpticalCommunications. The graph shows magnetic field distribution in asymmetric package at 49GHz.

Finite element simulation of dielectric waveguides. The graph shows aleaky mode in a integrated optical waveguide.

Simulation nanoscale materials in dynamic electromagnetic field. Theupper graph shows the charged particle and the nanotube, and the lowergraphs show both wireframe and space filled version of final structureafter impact process.

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Assoc Prof Lu YilongProgram [email protected]

Staff Members

Assoc Prof Lee Ching Kwang Assoc Prof Ma Jian Guo Assoc Prof Shen Zhongxiang

Assoc Prof Tan Soon Yim Assoc Prof Zhu Lei Asst Prof Lee Yee Hui Asst Prof Tan Eng Leong

Adjunct Assoc Prof Li ErPing

Dr Cheng MinResearch Fellow

Dr Li KaiResearch Fellow

Dr Tong Ming SzeResearch Fellow

Mr Wang QuanxinResearch Associate

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Evolutional Computation for Electromagnetics Lu Yilong IHPC/NTU ($320k)

Investigating The On-Wafer Coupling and Cross-Talk Effects Ma Jian-Guo IHPC/NTU ($320k)of CMOS RF ICs

Electromagnetic Modeling of Broad-band Packages for Optical Shen Zhongxiang IHPC/NTU ($320k)Communications

Development of a Low-cost Effective RCS Reduction Technique Shen Zhongxiang DSTA($200k)



Applications of Pseudo-Spectral Time Domain (PSTD) Tong Ming Sze SMF ($120k)Method for Studies of Periodical Structures in Microwave andOptoelectronics

MEng and PhD Theses Completed in 2004

Project Title Degree Student Supervisor(s)

Modelling and Optimization of Photonic Crystal Fibres MEng Wang Yifei Lu Yilong

Novel design of planar printed antennas with enhanced MEng Fu Rong Zhu Leiperformance

Miniaturized planar RF integrated filters with good MEng Shi Huamin Zhu Leiharmonic suppression

Printed periodic waveguide structures: full-wave PhD Kshetrimayum Zhu Leicharacterization, guided-wave characteristics and applications Rakhesh Singh


1. C. Feng, and Z. Shen, “Shielding effectiveness of a metallic enclosurewith multiple apertures”, Microwave and Optical Technology Letters,vol.43, no.5, Dec. 2004.

2. X. Shan, and Z. Shen, “Transverse slot antenna array in the broad-wall of an H-plane dielectric-filled rectangular waveguide”, IEEETrans. on Antennas and Propagation, Vol. 52, no.4, pp.1030-1038,April 2004.

3. C.C. Leong, and Z. Shen, “Subharmonic injection-locking balancedoscillator”, Microwave and Optical Technology Letters, Vol.41, No.4,pp.306-309, May 2004.

4. L. Jiang, and S.Y. Tan “A Simple Analytical Path Loss Model for UrbanCellular Communication Systems”, JEMWA, Vol. 18, No. 8, page1017-1032, 2004.

5. Y.J. Wang, W.J. Koh, and C.K. Lee, “Coupling Cross Section andShielding effectiveness Measurements on a coaxial Cable by BothMode-Tuned Reverberation Chamber and GTEM CellMethodologies”, Progress In Electromagnetics Research, PIER 47,Chapter 4, pp. 61-73. 2004.

6. Y.J. Wang, and C.K. Lee, “Compact and Broadband with MicrostripPatch Antenna for 3G IMT-2000 Handsets Applying Styrofoam andShorting-Posts”, Progress In Electromagnetics Research, PIER 47:Chapter 5, pp. 75-85, 2004.

7. M.S. Tong, M. Cheng, Y.L. Lu, Y.C. Chen, and V. Krozer, “Analysis ofphotonic band-gap (PBG) structures using an FDTD method”,Microwave and Optical Technology Letters, Vol. 41, No. 3, pp.173-177, May 2004.

8. M.S. Tong, Y.L. Lu, Y.C. Chen, M.W. Yang, Q.S. Cao, and V Krozer,“Design and Analysis of Planar Printed Microwave and PBG Filtersusing an FDTD Method”, Microelectronics Journal, Vol. 35, No. 9,pp.777-781, Sep. 2004.

9. W. Wang, Y.L. Lu, and J.S Fu, “Arbitrary planar microwave filter designby the FEM-GA approach”, Microwave and Optical TechnologyLetters, Vol. 41, No. 4, pp. 276-279, May 2004.

10. E. L. Tan, “Rollett-Based Single-Parameter Criteria for UnconditionalStability of Linear Two-Ports”, IEE Proceedings - Microwaves, Antennasand Propagation, Vol. 151, No. 4, pp.299-302, 2004.

11. E.L. Tan, “Reduced Conditions for the Constitutive Parameters of LossyBi-anisotropic media”, Microwave and Optical Technology Letters,Vol. 41, No. 2, pp. 133-135, 2004.

12. E.L. Tan, “Simple Derivation and Proof of Geometrical StabilityCriteria for Linear Two-Ports”, Microwave and Optical TechnologyLetters, Vol. 40, No. 1, pp.81-83, 2004.

13. K. Wu, L. Zhu, and R. Vahldieck, “Microwave Passive Components”,in Electrical Engineer’s Handbook, Academic Press & IEEE Press, Aug.2004.

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14. L. Zhu, and W. Menzel, “Broad-band microstrip-to-CPW transitionvia frequency-dependent electromagnetic coupling”, IEEE TransMicrowave Theory and Techniques, Vol.52, No. 5, pp.1517-1522,May 2004.

15. R.S. Kshetrimayum, and L. Zhu, “Hybrid MoM-immitance approachfor full-wave characterization of printed strips and slots in layeredwaveguide and its applications”, IEICE Trans Electronics, Vol.E87-C,No.5, pp.700-707, May 2004.

16. S. Sun, and L. Zhu, “Unified equivalent circuit model of finite-groundmicrostrip line open-end discontinuities using MoM-SOC technique”,IEICE Trans Electronics, Vol.E87-C, No.5, pp.828-831, May 2004.

17. Y.H. Lee, B.J. Cahill, S.J. Porter, and A.C. Marvin, “A novelevolutionary learning technique for multi-objective array antennaoptimization”, Journal of Electromagnetic Waves and Applications,Vol. 48, June 2004.

18. X.J. Zhang, A.Q. Liu, Y.H. Lee, and A. Alphones, “Near field andsurface field analysis of thin wire antenna in the presence ofconducting cube”, Progress in Electromagnetics Research, Vol. 45,March 2004.

CONTROL OF NETWORKS

Objective

In order to better understand the complexities of networkedsystems, and to develop techniques for improving theperformance of these systems, there is a need for gooddynamic models for networks to allow real-time control ofnetwork performance. Currently, most of the models usedfor network research are static, and they are not appropriatefor real-time control and optimization. With the dynamicmodels, we can effect real-time configuration of networkparameters in response to changing traffic loads andoperating conditions. In another aspect, networks can beconsidered as interconnected systems and there are greatopportunities to apply various system theories andoptimization techniques to analyze and improve theperformance of these networks. One of the main objectivesof this research programme is to develop practical dynamicmodels for networks that are suitable for real-timeapplications. The other objective is to develop and applynew system theories that will enhance the performance ofnetworks. The areas of research will involve dynamicresource allocation for multi-platform cellular networks,modeling and control of optical communication systemsand networked control systems.


The highlight for the year is the recognition from TheInternational Society for Optical Engineering forOutstanding Achievement in the Photonics InnovationVillage Competition held in conjunction with PhotonicsEurope 2004 in Strasbourg, France. The project on three-port all-fiber optical interleaver won the First Prize as thebest overall project, beating 16 other finalists from France,Germany, USA, Italy, Belgium, Poland, Ireland and Finland.The three-port all-fiber interleaver is designed through thesystem theoretic approach and is realized by cascadingthree 3 x 3 directional fiber couplers. An interleaver/de-interleaver works like an optical router that allows existingDWDM filters designed for operations with wide channelspacing to be extended to system designs with narrowchannel spacing in the range of 50GHz or even less.

Basically, interleavers/de-interleavers can be scaled tomatch whatever channel combination or routing that mightbe needed. The designed multi-port interleaver canefficiently increase the channel counts with fewer stagesof interleavers and provide more flexibility for optical signalmultiplexing. The all-fiber structure has an extremely lowinsertion loss. In addition to the novel structure, a systematicfilter design approach is developed to design the interleaverquantitatively with desirable specifications such as flat-toppassband/stopband, and passband isolation.

In other optical instrumentation and communication systemresearch activities, the main focus has been on exploringthe use of optical technologies for all-opticalcommunication network and precision measurement. Interms of network hierarchy, the study will be carried on attwo layers. First, optical crossing connection (OXC)technologies will be studied at the component layer.Second, the optical CDMA technology will be investigatedat the system layer. In the study of components, fiber-basedoptical components are targeted. They include tunablefilters, optical interleavers, EDFA gain equalizers, dispersioncompensators, optical switches, and optical add/dropmultiplexers. In this regards, a minimax method fordesigning the F3T (Fourier Filter Flat-top) interleaver isdemonstrated. Given a passband range, the proposedminimax method can produce an F3T interleaver with aspecified bandwidth, minimal insertion loss and higher

Presenting the Award-winning Project to EU Press

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isolation. In comparison with current interleaver design,the design parameters and the performance of theinterleaver are obtained analytically. The other achievementis the realization of multi-wavelength tunable laser. Thistunable laser is achieved by making use of feedback, thebasic concept of system theory. Using the developed opticalinterleavering technology, a dedicated feedback loop isdesigned in the ring laser to generate lasing beams atspecified wavelengths. A recent project is on optical systemsfor precision measurement, where the group has obtaineda cooperative research project from SIMTech to work onthe development of enabling technologies for nanoscalemeasrements by using near field fiber.

With the exponential growth of wireless network servicesin recent years, the key challenge of meeting the increasingdemand lies in the efficient use of the spectrum. Currently,cellular networks are operated in the open loop withnetwork parameters tuned by the network vendors once ina while to cater for changes in demand. This is because theavailable models are static flow models which are notsuitable for analysis and synthesis of real-time traffic controlrules. One of the key contributions made by the group isthe development of dynamical flow models for cellularnetworks to allow close-loop controllers to be designed totune the network parameters in real-time.

Another interesting result is the development of correctioncodes for high-speed digital data transmission over amultidimensional space. So far, the result for correcting asingle error has been developed. However, for practicalapplications, good error correction codes formultidimensional signals that can correct and detect morethan one error are required and this is an ongoing researchfocus of the group.

SLED Light Source

Assoc Prof Soh CheongBoon

Program [email protected]

Staff Members

Assoc Prof Erry Gunawan Assoc Prof Low Kay Soon Prof Soh Yeng Chai

Assoc Prof Soong Boon Hee Assoc Prof Wen Changyun Adj Asst Prof Zhang Ying

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Enabling Technologies for Nanoscale Measurements by near Zhang Ying SIMTech ($581k)Field Fiber Optics Soh Yeng Chai

System Theoretic Approach to Optical Filter Design for Precision Soh Yeng Chai RGM ($248k)Measurements



Multi-wavelength Modulation Technologies for Nano-scale Zhang Ying SIMTech ($459k)Measurement by Fiber Interferometry and Near-field Fiber Optics Soh Yeng Chai


1. Q.J. Wang, Y. Zhang, and Y.C. Soh, “Design of Spectrum EqualizationFilter for SLED Light Source”, Optics Communications, Vol.229,No.1-6, pp.223-231, 2004.

2. Q.J. Wang, Y. Zhang, and Y.C. Soh, “All-fiber 3x3 Interleaver Designwith Flat-Top Passband”, IEEE Photonics Technology Letters, Vol. 16,No.1, pp.168-170, 2004.

3. T. Liu, Y.C. Soh, Q.J. Wang, Y. Zhang, and Z. P. Fang, “ChannelWavelength Selectable Single/dual-wavelength Erbium-doped FiberRing-laser”, SPIE Journal of Optical Engineering, Vol.43, No. 1,pp.209-213, 2004.

4. J.Y. Pan, C.B. Soh, and E. Gunawan, “Reduced-complexity iterativemultiuser detection for DS-CDMA”, accepted, Wireless PersonalCommunications, 2004.

5. X.D. Dong, C.B. Soh, and E. Gunawan, “On codes from cyclotomicfields for multidimensional signals”, accepted, IMA Journal ofMathematical Control and Information, 2004.

6. C. Cao, L. Xie, S. Xie, and H. Zhang, “A robust channel estimator forDS-CDMA systems under multipath fading channels,” Proc. IEEEGlobalcom, USA, 2004.

7. S.W. Kok, Y. Zhang, C. Wen, and Y.C. Soh, “Dual detection for opticalcode division multiple access”, accepted, Optical Engineering Letters,2004.

8. S.W. Kok, Y. Zhang, C. Wen, and Y.C. Soh, “Performance comparisonbetween 2D correlation and chip-level receivers for OCDMA”, Proc.47th IEEE International Midwest Symposium on Circuits and Systems,Japan, July 2004.

MODELING, OPTIMIZATION AND CONTROL TECHNIQUES

Objectives

Under this programme, general methods will be developedto model and control complex systems as well as to optimizethe operation of such systems. This research programmefocuses on exploring both the fundamental and appliedaspects of such methods.


The main activities under this programme are Modelingand Design of Active Auto-focus Systems with Applicationin Image Processing, Switching Systems andMultidimensional Systems as well as practical applicationsof fundamental theory developed.

1. Modeling and Design of Active Auto-focus Systems withApplication in Image Processing:

This involves the development of three enablingtechnologies for in-situ 3D inspection. Firstly, an adaptive

auto-focusing technology is established. It distinguishesitself from existing similar technologies in that it employsauto-focusing measure explicitly. Thus, accurate focusinginformation can be extracted. This in turn ensures that the3D measurements using focusing can attain high accuracy.In addition, auto-focusing is carried out by an adaptiveclose-loop control. Therefore, noises produced duringimaging and uncertainties due to modeling of the imagingsystem can be greatly suppressed. Secondly, blur-invariantrecognition methodology is developed to identify on-the-flying objects from their images captured during theirmotion. The developed methods are robust to the blurcaused by motion. Thirdly, line-scan phase-shifting schemesare proposed to measure the 3D profiles of the on-the-flyingobjects in the presence of phase-shifting errors caused bycalibration, the asynchronous motion-and-imaging and/oraccumulated motion errors. Systematic phase measurementformulae are obtained explicitly. In comparison to theexisting phase-shifting algorithms, the developed phase-shifting measurement approach not only reduces thefluctuations but also removes the biases in the phase

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measurement. They also exhibit robust performance in thepresence of random phase errors and nonlinear phase-errors. Therefore, the precision of 3D profiles measurementsof on-the-flying objects is guaranteed. As a platform todemonstrate the obtained technologies, a line-scanningimaging system is built. The imaging system adopts aminimal-mechanical-complexity design consisting of a line-scanning camera, a conveyer, and a line color projectorwhich is designed dedicatedly to project RBG Phase-shiftedline gratings. The image system developed with Visual C++provides various functions for motion control and line-scanimaging. The PID based visual-servo function is provided.In addition, a phase-shifting simulator is also included,which is conveniently used to simulate various kinds ofphase-shifting errors including nonlinear errors and randomerrors.

2. Switched and Impulsive Systems

A switched and impulsive system is a collection of finitecontinuous variable systems (CVSs) along with a discreteevent system (DES) governing the impulsive “switching”among them. There are indeed many switched andimpulsive systems that occur either naturally or by designin the fields of control, communication, computer andsignal processes. Some examples are switched/serversystems, switched flow network, Chua’s circuit, computerdisk drives, intelligent vehicle/highway systems, mobilerobots of Hilare type, an Internet router, a scalable videocoding system, a chaotic-based secure communicationsystem and so on. Indeed, switched and impulsive systemshave numerous applications in fields like mechanicalsystems, automotive industry, aircraft, air traffic control,network control, chaotic-based secure communication,quality of service in the Internet, and video coding. Activitiesin this area include analysis, design and applications ofsuch systems.

3. Multidimensional Systems

Multi-dimensional systems are systems whose input andoutput signals are functions of more than one variable.Multidimensional and 2-D systems exist in many practicalapplications, e.g. sound, seismic, underwater signalpropagation, image data processing and transmission, visualrecognition of robotic systems and medical and biologicalinformation and image processing. In this area, weinvestigate methods and algorithms for analysis offundamental properties and for processing, filtering,optimization and control of multidimensional signals,images and systems. Applications of our methods andalgorithms include medical image processing, active noisecancellation and multirate filter banks.

Overall Structure of Line-Scanning Imaging System

Motion Control System in the Line-Scanning Imaging System

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Assoc Prof Wen ChangyunProgram Director

[email protected]

Staff Members

Assoc Prof Lee Peng Hin Adj Asst Prof Li Zhengguo Assoc Prof Lin Zhiping

Assoc Prof Ling Keck Voon Assoc Prof Low Kay Soon Assoc Prof Lu Yilong Prof Soh Yeng Chai

Assoc Prof Wong Jia Ying,Patricia

Prof Xie Lihua Assoc Prof Zhang Cishen Adj Asst Prof Zhang Ying



Active Vision and Its Application in Industrial Inspection Wen Changyun NTU ($123.6k)



Active Anisotropic Diffusion Technologies in Image Processing Zhang Ying SIMTech($160k)Wen Changyun

180180

Seminars


Wen Changyun Design of Adaptive Auto-Focus Systems with EEE, NTUApplication in Image Processing

Wen Changyun Kalman Filter and Its Applications in Estimation and EEE, NTUTracking of Moving Objects – Part 1

Wen Changyun Kalman Filter and Its Applications in Estimation and EEE, NTUTracking of Moving Objects – Part 2

Soh Yeng Chai Chao-based Secure Communications – Synchronization EEE, NTUand Security

Soh Yeng Chai A Nonlinear Sliding Mode Observer Design for a Class EEE, NTUof Nonlinear Uncertain Systems


1. P.H. Lee, and Y.C. Soh, “Simultaneous H_infinity stabilization”,International Journal of Control, Vol 77, No 2, pp 111-117, Jan.2004.

2. Z. Lin, L. Xu, and Q. Wu, “Applications of Grobner bases to signaland image processing: a survey”, accepted, Linear AlgebraApplications, 2004.

3. L. Xu, Q. Wu, Z. Lin, and Y. Anazawa, “A mu approach to robuststability analysis of nD discrete systems” Multidimensional Systemsand Signal Processing, Vol. 15, No. 3, pp. 277-293, 2004.

4. W. Paszke, J. Lam, K. Galkowski, S. Xu, and Z. Lin, “Robust stabilityand stabilization of 2D discrete state-delayed systems”,Systems and Control Letters, Vol. 51, pp. 277-291, Netherlands,2004.

5. K.S. Low, and M.T. Keck, “A high performance precision machine”,Proc. IEEE Conference on Robotics, Automation and Mechatronics,Singapore, Dec. 2004.

6. K.S. Low, and T.Z. Wong, “Optimisation of a hard disk drive servosystem using multiobjective genetic algorithm” , Proc. IEEEConference on Cybernetics and Intelligent Systems, Singapore, Dec.2004.

7. Z.G. Li, Y.C. Soh, and C.Y. Wen, “Switched and Impulsive Systems-Analysis, Design and Applications”, Springer-Verlag, 2004.

8. K. Li, Y.C. Soh, and Z.G. Li, “Synchronization of Lorenz Systems viaImpulsive Control and Sporadic Coupling”, accepted, Int. J. ofBifurcation and Chaos, U.S.A., 2004.

9. K. Li, Y.C. Soh, and Z.G. Li, “Two-stage impulsive control for thesynchronization of chaotic systems”, Proc. 12th InternationalWorkshop on Nonlinear Dynamics of Electronic Systems, Portugal,2004.

10. J. Zhou, C. Wen, and Y. Zhang, “Adaptive backstepping control of aclass of uncertain nonlinear systems with unknown backlash-likehysteresis”, accepted, IEEE Trans. Automatic Control, 2004.

11. J. Zhou, C. Wen, and Y. Zhang, “Adaptive backstepping control of aclass of MIMO systems”, Proc. 2004 IEEE International Symposiumon Intelligent Control (ISIC), Taiwan, Sept. 2004.

12. P.J.Y. Wong, and Y.C. Soh, “Triple fixed-sign solutions in modellinga system with Hermite boundary conditions”, accepted, Archives ofInequalities, USA, 2004.

13. J. Henderson, and P.J.Y. Wong, “On multiple fixed-sign solutions ofa discrete system with Hermite boundary condition”, Journal ofMathematical Analysis and Applications, USA, Vol. 297, pp. 87 –110, 2004.

14. R.P. Agarwal, D. O’ Regan, and P.J.Y. Wong, “Eigenvalues of a systemof Fredholm integral equations”, Mathematical and ComputerModelling, U.K., Vol.39, pp. 1113 – 1150, 2004.

15. L. Lu, L. Xie, and W.J. Cai, “H2 controller design for networked controlsystems”, Asian Journal of Control, Vol. 6, No.1, 2004.

16. H. Zhang, D. Zhang, and L. Xie, “An innovation approach to H-infinity prediction with application to systems with delayedmeasurements,” accepted, Automatica, 2004.

17. K. Li, Y.C. Soh, and C. Zhang, “A frequency aliasing approach tochaos-based cryptosystems”, accepted, IEEE Transactions on Circuitsand Systems-I, 2004.

18. T. Chu, and C. Zhang, “Qualitative analysis of discrete competitive-cooperative neural networks”, accepted, Differential Equations andDynamical Systems, 2004.

19. C. Zhang, and Y. Zheng, “A polynomial approach to discrete timenonlinear system controllability”, International Journal of Control,Vol. 77, pp. 491-497, 2004.

20. H. Bi, Y. Zhang, K.V. Ling, and C. Wen, “A Class of 4+1-phasealgorithms with error compensation”, Applied Optics, Vol.43, No.21, pp. 4199-4207, 2004.

21. Y. Liu, Z.G. Li, and Y.C. Soh, “Motion compensated temporal filteringwith optimal temporal distance between each motion compensationpair”, Proc. ICIP 2004, Singapore, 2004.

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