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SENSOR SELECTION FOR RANDOM FIELD ESTIMATION IN WIRELESS SENSOR NETWORKS

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Journal of Systems Science & Complexity 2012年第1期25卷 46-59页

作者： Yang WENG Lihua XIE Wendong XIAO College of Mathematics Sichuan University school of electrical and electronic engineering Nanyang Technological University school of Automation and electrical engineering University of Science and Technology Beijing

This paper studies the sensor selection problem for random field estimation in wireless sensor networks. The authors first prove that selecting a set of I sensors that minimize the estimation error under the D-optimal criterion is NP-complete. The authors propose an iterative algorithm to pursue a suboptimal solution. Furthermore, in order to improve the bandwidth and energy efficiency of the wireless sensor networks, the authors propose a best linear unbiased estimator for a Gaussian random field with quantized measurements and study the corresponding sensor selection problem. In the case of unknown covariance matrix, the authors propose an estimator for the covariance matrix using measurements and also analyze the sensitivity of this estimator. Simulation results show the good performance of the proposed algorithms.

关键词： BLUE covarianee matrix exchange algorithm NP-completeness quantization random field sensor selection.

Service-based Reliability Analysis of Integrated Electricity-heat Systems Considering Thermal Dynamics

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Journal of Modern Power Systems and Clean Energy 2023年第4期11卷 1176-1190页

作者： Xunhu Yin Minglei Bao Yi Ding Chengjin Ye Peng Wang Lalit Goel College of electrical engineering Zhejiang UniversityHangzhou 310027China electrical and electronic engineering school Nanyang Technological UniversitySingapore 639798

The essential task of integrated electricity-heat systems(IEHSs)is to provide customers with reliable electric and heating *** the perspective of customers,it is reasonable to analyze the reliabilities of IEHSs based on the ability to provide energy services with a reasonable assurance of continuity and quality,which are termed as service-based *** to the thermal inertia existing in IEHSs,the heating service performances can present slow dynamic characteristics,which has a great impact on the service satisfaction of *** neglect of such thermal dynamics will bring about inaccurate service-based reliability measurement,which can lead to the inefficient dispatch decisions of system ***,it is necessary to provide a tool which can analyze the servicebased reliabilities of IEHSs considering the impacts of thermal *** paper firstly models the energy service performance of IEHSs in contingency ***,the nodal energy supplies are obtained from the optimal power and heat flow model under both variable hydraulic and thermal conditions,in which the transmission-side thermal dynamics are *** this basis,the energy service performances for customers are further determined with the formulation of demandside thermal ***,a service-based reliability analysis framework for the IEHSs is proposed utilizing the timesequential Monte Carlo simulation(TSMCS)technique with the embedded decomposition ***,the indices for quantifying service-based reliabilities are defined based on the traditional reliability indices,where dynamic service performances and service satisfactions of customers are both *** simulations are carried out with a test system to validate the effectiveness of the proposed framework.

关键词： Energy service integrated electricity-heat system reliability thermal dynamics

Nash equilibrium seeking with prescribed performance

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Control Theory and Technology 2023年第3期21卷 437-447页

作者： Chao Sun Guoqiang Hu Continental-NTU Corporate Lab Nanyang Technological University639798 NanyangSingapore school of electrical and electronic engineering Nanyang Technological University639798 NanyangSingapore

In this work,we study a Nash equilibrium(NE)seeking problem for strongly monotone non-cooperative games with prescribed *** general NE seeking algorithms,the proposed prescribed-performance NE seeking laws ensure that the convergence error evolves within a predefined ***,the settling time,convergence rate,and maximum overshoot of the algorithm can be ***,we develop a second-order Newton-like algorithm that can guarantee prescribed performance and asymptotically converge to the NE of the ***,we develop a first-order gradient-based *** remove some restrictions on this first-order algorithm,we propose two discontinuous dynamical system-based algorithms using tools from non-smooth analysis and adaptive *** study the special case in optimization ***,we investigate the robustness of the *** can be proven that the proposed algorithms can guarantee asymptotic convergence to the Nash equilibrium with prescribed performance in the presence of bounded ***,we consider a second-order dynamical system *** simulation results verify the effectiveness and efficiency of the algorithms,in terms of their convergence rate and disturbance rejection ability.

关键词： Nash equilibrium seeking Non-cooperative games Prescribed performance Disturbance rejection

Photonic MEMS tunable laser sources

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The Journal of China Universities of Posts and Telecommunications 2009年第3期16卷 1-3页

作者： LIU Ai-qun school of electrical and electronic engineering Nanyang Technological University 50 Nanyang Avenue 639798 Singapore

This article covers laser configurations, design and experiments of photonic microelectromechanical systems （MEMS） tunable laser sources. Three different types of MEMS tunable lasers such as MEMS coupled-cavity lasers, injection-locked laser systems and dual-wavelength tunable lasers are demonstrated as examples of natural synergy of MEMS with photonics. The expansion and penetration of the MEMS technology to silicon optoelectronic creates on-chip optical systems at an unprecedented scale of integration. While producing better integration with robustness and compactness, MEMS improves the functionalities and specifications of laser chips. Additionally, MEMS tunable lasers are featured with small size, high tuning speed, wide tuning range and CMOS compatible integration, which broaden their applications to many fields.

关键词： photonic MEMS tunable laser photonics silicon optoelectronics

Virtual sensing for gearbox condition monitoring based on kernel factor analysis

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Petroleum Science 2017年第3期14卷 539-548页

作者： Jin-Jiang Wang Ying-Hao Zheng Lai-Bin Zhang Li-Xiang Duan Rui Zhao school of Mechanical and Transportation engineering China University of Petroleum school of electrical and electronic engineering Nanyang Technological University

Vibration and oil debris analysis are widely used in gearbox condition monitoring as the typical indirect and direct sensing techniques. However, they have their own advantages and disadvantages. To better utilize the sensing information and overcome its shortcomings, this paper presents a virtual sensing technique based on artificial intelligence by fusing low-cost online vibration measurements to derive a gearbox condition indictor, and its performance is comparable to the costly offline oil debris measurements. Firstly, the representative features are extracted from the noisy vibration measurements to characterize the gearbox degradation conditions. However, the extracted features of high dimensionality present nonlinearity and uncertainty in the machinery degradation process. A new nonlinear feature selection and fusion method,named kernel factor analysis, is proposed to mitigate the aforementioned challenge. Then the virtual sensing model is constructed by incorporating the fused vibration features and offline oil debris measurements based on support vector regression. The developed virtual sensing technique is experimentally evaluated in spiral bevel gear wear tests,and the results show that the developed kernel factor analysis method outperforms the state-of-the-art featureselection techniques in terms of virtual sensing model accuracy.

关键词： Gearbox condition monitoring Virtualsensing Feature selection and fusion

Design to reduce electromagnetic vibration in integral-slot SPM machine considering force modulation effect

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Science China(technological Sciences) 2022年第8期65卷 1867-1877页

作者： ZHU ShengDao ZHAO WenXiang JI JingHua LIU GuoHai LEE Christopher H.T. school of electrical and Information engineering Jiangsu UniversityZhenjiang 212013China school of electrical and electronic engineering Nanyang Technological UniversitySingapore 639798Singapore

In this paper, two different designs, with dummy slots and bread-loaf magnets techniques, are presented to reduce the electromagnetic vibration in integral-slot surface-mounted permanent-magnet(SPM) machines. Firstly, the stator slotting effect on the magnetic field modulation and radial force modulation is investigated. It reveals the amplitude of the modulated magnetic field and modulated radial force is greatly affected by the slot opening effect, while the spatial order is closely associated with the slot numbers. Subsequently, the dummy slots and bread-loaf magnets design are developed for a 36-slot/12-pole integral-slot SPM machine to reduce the electromagnetic vibration. Finally, two SPM machines, with conventional and bread-loaf magnets,are manufactured. Experimental tests are carried out to validate the theoretical analyses.

关键词： surface-mounted permanent-magnet machine slot opening width dummy slots bread-loaf magnets vibration reduction

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Game-theoretic multi-agent motion planning in a mixed environment

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Control Theory and Technology 2024年第3期22卷 379-393页

作者： Xiaoxue Zhang Lihua Xie school of electrical and electronic engineering Nanyang Technological UniversitySingapore City 639798Singapore

The motion planning problem for multi-agent systems becomes particularly challenging when humans or human-controlled robots are present in a mixed *** address this challenge,this paper presents an interaction-aware motion planning approach based on game theory in a receding-horizon manner Leveraging the framework provided by dynamic potential games for handling the interactions among agents,this approach formulates the multi-agent motion planning problem as a differential potential game,highlighting the effectiveness of constrained potential games in facilitating interactive motion planning among ***,online learning techniques are incorporated to dynamically learn the unknown preferences and models of humans or human-controlled robots through the analysis of observed *** evaluate the effectiveness of the proposed approach,numerical simulations are conducted,demonstrating its capability to generate interactive trajectories for all agents,including humans and human-controlled agents,operating within the mixed *** simulation results illustrate the effectiveness of the proposed approach in handling the complexities of multi-agent motion planning in real-world scenarios.

关键词： Motion planning Differential potential game Multi-agent systems Constrained potential game

PEAK COVARIANCE STABILITY OF A RANDOM RICCATI EQUATION ARISING FROM KALMAN FILTERING WITH OBSERVATION LOSSES

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Journal of Systems Science & Complexity 2007年第2期20卷 262-272页

作者： Li XIE Lihua XIE school of electrical and electronic engineering Nanyang Technological University Nanyang Avenue 639798 Singapore

We consider the stability of a random Riccati equation with a Markovian binary jump coefficient. More specifically, we are concerned with the boundedness of the solution of a random Riccati difference equation arising from Kalman filtering with measurement losses. A sufficient condition for the peak covariance stability is obtained which has a simpler form and is shown to be less conservative in some cases than a very recent result in existing literature. Furthermore, we show that a known sufficient condition is also necessary when the observability index equals one.

关键词： Kalman filtering observation losses Random Riccati equations stability stopping time

Improvement of polling and scheduling scheme for real-time transmission with HCCA of IEEE 802.11p protocol

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The Journal of China Universities of Posts and Telecommunications 2013年第3期20卷 60-66页

作者： ZHANG Bing MA Mao-de LIU Chun-feng SHU Yan-tai school of Computer Science and Technology Tianjin University school of electrical and electronic engineering Nanyang Technological University

This paper addresses the issue of real-time data transmission in vehicles to roadside （V2R） environment by the hybrid coordination function （HCF） of controlled channel access （HCCA） specified by the IEEE 802.1 lp standard. HCCA is one of the medium access mechanisms in the IEEE 802.11 standard, and uses the polling scheme similar to the point coordination function （PCF） to provide reliable quality of service （QoS）, which may cause resource overshooting and high time consuming. This paper tries to improve the performance of the HCCA polling scheme and designs new data transmission scheduling scheme. The simulation results of the proposal are compared with those of the standard strategy. Simulation results demonstrate that the improved HCCA has lower delay, loss rate, and higher throughput than those of the standard one.

关键词： IEEE 802.1 lp HCCA V2R polling scheduling