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Time varying congestion pricing for multi-class and multi-mode transportation system with asymmetric cost functions
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作者 钟绍鹏 邓卫 《Journal of Southeast University(English Edition)》 EI CAS 2011年第1期77-82,共6页
This paper considers the problem of time varying congestion pricing to determine optimal time-varying tolls at peak periods for a queuing network with the interactions between buses and private cars.Through the combin... This paper considers the problem of time varying congestion pricing to determine optimal time-varying tolls at peak periods for a queuing network with the interactions between buses and private cars.Through the combined applications of the space-time expanded network(STEN) and the conventional network equilibrium modeling techniques,a multi-class,multi-mode and multi-criteria traffic network equilibrium model is developed.Travelers of different classes have distinctive value of times(VOTs),and travelers from the same class perceive their travel disutility or generalized costs on a route according to different weights of travel time and travel costs.Moreover,the symmetric cost function model is extended to deal with the interactions between buses and private cars.It is found that there exists a uniform(anonymous) link toll pattern which can drive a multi-class,multi-mode and multi-criteria user equilibrium flow pattern to a system optimum when the system's objective function is measured in terms of money.It is also found that the marginal cost pricing models with a symmetric travel cost function do not reflect the interactions between traffic flows of different road sections,and the obtained congestion pricing toll is smaller than the real value. 展开更多
关键词 time varying congestion pricing ASYMMETRIC MULTI-CLASS MULTI-MODE MULTI-CRITERIA
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IDENTIFICATION OF NONLINEAR TIME VARYING SYSTEM USING FEEDFORWARD NEURAL NETWORKS 被引量:2
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作者 王正欧 赵长海 《Transactions of Tianjin University》 EI CAS 2000年第1期8-13,共6页
As it is well known,it is difficult to identify a nonlinear time varying system using traditional identification approaches,especially under unknown nonlinear function.Neural networks have recently emerged as a succes... As it is well known,it is difficult to identify a nonlinear time varying system using traditional identification approaches,especially under unknown nonlinear function.Neural networks have recently emerged as a successful tool in the area of identification and control of time invariant nonlinear systems.However,it is still difficult to apply them to complicated time varying system identification.In this paper we present a learning algorithm for identification of the nonlinear time varying system using feedforward neural networks.The main idea of this approach is that we regard the weights of the network as a state of a time varying system,then use a Kalman filter to estimate the state.Thus the network implements nonlinear and time varying mapping.We derived both the global and local learning algorithms.Simulation results demonstrate the effectiveness of this approach. 展开更多
关键词 IDENTIFICATION nonlinear time varying system feedforward neural network Kalman filter Q and R matrices
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Novel delay-dependent stability analysis of Takagi-Sugeno fuzzy uncertain neural networks with time varying delays 被引量:1
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作者 M. Syed Ali 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第7期49-60,共12页
This paper presents the stability analysis for a class of neural networks with time varying delays that are represented by the Takagi^ugeno IT-S) model. The main results given here focus on the stability criteria usi... This paper presents the stability analysis for a class of neural networks with time varying delays that are represented by the Takagi^ugeno IT-S) model. The main results given here focus on the stability criteria using a new Lyapunov functional. New relaxed conditions and new linear matrix inequality-based designs are proposed that outperform the previous results found in the literature. Numerical examples are provided to show that the achieved conditions are less conservative than the existing ones in the literature. 展开更多
关键词 neutral neural networks linear matrix inequality Lyapunov stability time varying delays
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Delay dependent stability criteria for recurrent neural networks with time varying delays 被引量:1
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作者 Zhanshan WANG Huaguang ZHANG 《控制理论与应用(英文版)》 EI 2009年第1期9-13,共5页
This paper aims to present some delay-dependent global asymptotic stability criteria for recurrent neural networks with time varying delays. The obtained results have no restriction on the magnitude of derivative of t... This paper aims to present some delay-dependent global asymptotic stability criteria for recurrent neural networks with time varying delays. The obtained results have no restriction on the magnitude of derivative of time varying delay, and can be easily checked due to the form of linear matrix inequality. By comparison with some previous results, the obtained results are less conservative. A numerical example is utilized to demonstrate the effectiveness of the obtained results. 展开更多
关键词 Recurrent neural networks STABILITY time varying delay Linear matrix inequality
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ANN-Time Varying GARCH Model for Processes with Fixed and Random Periodicity 被引量:1
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作者 Elias K. Karuiru John Mwaniki Kihoro +1 位作者 Thomas Mageto Anthony Gichuhi Waititu 《Open Journal of Statistics》 2021年第5期673-689,共17页
Financial Time Series Forecasting is an important tool to support both individual and organizational decisions. Periodic phenomena are very popular in econometrics. Many models have been built aiding capture of these ... Financial Time Series Forecasting is an important tool to support both individual and organizational decisions. Periodic phenomena are very popular in econometrics. Many models have been built aiding capture of these periodic trends as a way of enhancing forecasting of future events as well as guiding business and social activities. The nature of real-world systems </span><span style="font-family:Verdana;">is</span><span style="font-family:Verdana;"> characterized by many uncertain fluctuations which makes prediction difficult. In situations when randomness is mixed with periodicity, prediction is even much harder. We therefore constructed an ANN Time Varying Garch model with both linear and non-linear attributes and specific for processes with fixed and random periodicity. To eliminate the need for time series linear component filtering</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> we incorporated the use of Artificial Neural Networks (ANN) and constructed Time Varying GARCH model on its disturbances. We developed the estimation procedure of the ANN time varying GARCH model parameters using non parametric techniques. 展开更多
关键词 Fixed Periodicity Random Periodicity Artificial Neural Network time varying GARCH
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LMS-LIKE ESTIMATION FOR TIME VARYING PARAMETERS
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作者 陈翰馥 郭雷 张纪峰 《Acta Mathematica Scientia》 SCIE CSCD 1991年第3期327-340,共14页
An LMS-like algorithm is applied for estimating the time-varying parameter theta-n in the linear model y(n) = phi-n-tau-theta-n + upsilon-n, which is general in the sense that none of the probabilistic properties such... An LMS-like algorithm is applied for estimating the time-varying parameter theta-n in the linear model y(n) = phi-n-tau-theta-n + upsilon-n, which is general in the sense that none of the probabilistic properties such as stationarity, Markov property, independence and ergodicity is imposed on any of the processes {y(n)}, {phi-n}, {theta-n} and {upsilon-n}. It is shown that the alpha-th moment of the estimation error is of order of the alpha-th moment of the observation noise and the parameter variation w(n) change in equivalence theta-n - theta-n-1. 展开更多
关键词 LMS-LIKE ESTIMATION FOR time varying PARAMETERS der Zhang ACTA 石蕊 少司
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Stabilizing controller design for nonlinear fractional order systems with time varying delays
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作者 AZIZI Abdollah FOROUZANFAR Mehdi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第3期681-689,共9页
To deal with stabilizing of nonlinear affine fractional order systems subject to time varying delays,two methods for finding an appropriate pseudo state feedback controller are discussed.In the first method,using the ... To deal with stabilizing of nonlinear affine fractional order systems subject to time varying delays,two methods for finding an appropriate pseudo state feedback controller are discussed.In the first method,using the Mittag-Lefler function,Laplace transform and Gronwall inequality,a linear stabilizing controller is derived,which uses the fractional order of the delayed system and the upper bound of system nonlinear functions.In the second method,at first a sufficient stability condition for the delayed system is given in the form of a simple linear matrix inequality(LMI)which can easily be solved.Then,on the basis of this result,a stabilizing pseudo-state feedback controller is designed in which the controller gain matrix is easily computed by solving an LMI in terms of delay bounds.Simulation results show the effectiveness of the proposed methods. 展开更多
关键词 fractional order nonlinear system time varying delay state feedback control linear matrix inequality(LMI) stabilizing
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ANN-Time Varying GARCH Model: Simulations and Application in Modelling Temperature for Weather Derivatives
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作者 Elias K. Karuiru John Mwaniki Kihoro +1 位作者 Thomas Mageto Anthony Gichuhi Waititu 《Open Journal of Statistics》 2022年第3期433-441,共9页
In economics and finance, minimising errors while building an abstract representation of financial assets plays a critical role due to its application in areas such as risk management, decision making and option prici... In economics and finance, minimising errors while building an abstract representation of financial assets plays a critical role due to its application in areas such as risk management, decision making and option pricing. Despite the many methods developed to handle this problem, modelling processes with fixed and random periodicity still remains a major challenge. Such methods include Artificial Neural networks (ANN), Fuzzy Inference system (FIS), GARCH models and their hybrids. This study seeks to extend literature of hybrid ANN-Time Varying GARCH model through simulations and application in modelling weather derivatives. The study models daily temperature of Kenya using ANN-Time Varying GARCH (1, 1), Time Lagged Feedforward neural network (TLNN) and periodic GARCH family models. Mean square error (MSE) and coefficient of determination R<sup>2</sup> were used to determine performance of the models under study. Results obtained show that the ANN-Time Varying GARCH model gives the best results. 展开更多
关键词 Artificial Neural Network time varying GARCH Weather Derivatives TEMPERATURE
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Equilibrium Control Theory and Direct Method of Feedback Linearization for Nonlinear Time Varying Systems 被引量:1
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作者 王庆林 陈悦 《Journal of Beijing Institute of Technology》 EI CAS 1999年第3期306-311,共6页
Aim To present a simple and effective method for the design of nonlinear and time varying control system. Methods A new concept of dynamic equilibrium of a system and its stability were presented first. It was poin... Aim To present a simple and effective method for the design of nonlinear and time varying control system. Methods A new concept of dynamic equilibrium of a system and its stability were presented first. It was pointed out that what is controlled directly by the input of a control system is the system's dynamic equilibrium rather than the states. Based on it, a new feedback linearization method for nonlinear system based on the Lyapunov direct method was given. Simulation studies were also carried out. Results The example and simulation show that by use of the method, the controller design becomes very simple and the control effect is quite satisfying. Conclusion The new method unifies the stabilizing problem(regulating problem) with the tracking problem. It is a very simple and effective method for the design of nonlinear and time varying control system. 展开更多
关键词 dynamic equilibrium feedback linearization nonlinear system time varying system stability
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Detection of time varying pitch in tonal languages: an approach based on ensemble empirical mode decomposition 被引量:5
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作者 Hong HONG Xiao-hua ZHU +2 位作者 Wei-min SU Run-tong GENG Xin-long WANG 《Journal of Zhejiang University-Science C(Computers and Electronics)》 SCIE EI 2012年第2期139-145,共7页
A method based on ensemble empirical mode decomposition (EEMD) is proposed for accurately detecting the time varying pitch of speech in tonal languages. Unlike frame-, event-, or subspace-based pitch detectors, the ti... A method based on ensemble empirical mode decomposition (EEMD) is proposed for accurately detecting the time varying pitch of speech in tonal languages. Unlike frame-, event-, or subspace-based pitch detectors, the time varying information of pitch within the short duration, which is of crucial importance in speech processing of tonal languages, can be accurately extracted. The Chinese Linguistic Data Consortium (CLDC) database for Mandarin Chinese was employed as standard speech data for the evaluation of the effectiveness of the method. It is shown that the proposed method provides more accurate and reliable results, particularly in estimating the tones of non-monotonically varying pitches like the third one in Mandarin Chinese. Also, it is shown that the new method has strong resistance to noise disturbance. 展开更多
关键词 Ensemble empirical mode decomposition time varying pitch Tonal language Noise restraint
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Parametric modeling of hypersonic ballistic data based on time varying auto-regressive model 被引量:3
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作者 HU YuDong LI JunLong +2 位作者 ZHANG Zhao JING WuXing GAO ChangSheng 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2020年第8期1396-1405,共10页
For describing target motion in hypersonic vehicle defense,a parametric analyzing and modeling method on ballistic data is proposed based on time varying auto-regressive method.Ballistic data are regarded as non-stati... For describing target motion in hypersonic vehicle defense,a parametric analyzing and modeling method on ballistic data is proposed based on time varying auto-regressive method.Ballistic data are regarded as non-stationary random signal,where the hidden internal law is studied.Firstly,ballistic data are decomposed into smooth linear trend signal and non-stationary periodic skip signal with ensemble empirical mode decomposition method to avoid mutual interference between different modal data.Secondly,the linear trend signal and the periodic skip signal are modeled separately.The linear trend signal is approximated by power function regressive estimator and the periodic skip signal is modeled based on time varying auto-regressive method.In order to determine optimal model orders,a novel method is presented based on information theoretic criteria and the criteria of minimizing the mean absolute error.Finally,the consistency test is conducted by investigating the time-frequency spectrum characteristics and statistical properties of outputs of the parametric model established above and dynamics model under the same initial condition.Simulation results demonstrate that the parametric model established by the proposed method shares a high consistency with the original dynamics model. 展开更多
关键词 hypersonic vehicle parametric modeling ballistic data decomposition time varying auto-regressive periods drift
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Control Schemes for Passive Teleoperation Systems over Wide Area Communication Networks with Time Varying Delay 被引量:1
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作者 Shafiqul Islam Xiaoping P.Liu +2 位作者 Abdulmotaleb El Saddik Lakmal Seneviratne Jorge Dias 《International Journal of Automation and computing》 EI CSCD 2014年第1期100-108,共9页
In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and... In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and velocity signals of the master and slave manipulators.Nonlinear adaptive control terms are employed locally to cope with uncertain parameters associated with the gravity loading vector of the master and slave manipulators.Lyapunov-Krasovskii function is employed for three methods to establish asymptotic tracking property of the closed loop teleoperation systems.The stability analysis is derived for both symmetrical and unsymmetrical time varying delays in the forward and backward communication channel that connects the local and remote sites.Finally,evaluation results are presented to illustrate the efectiveness of the proposed design for real-time applications. 展开更多
关键词 TELEOPERATION TELEROBOTICS Lyapunov-Krasovskii functional time varying delay passive systems
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A blind separation method of overlapped multi-components based on time varying AR model 被引量:1
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作者 CAI QuanWei WEI Ping XlAO XianCi 《Science in China(Series F)》 2008年第1期81-92,共12页
A method utilizing single channel recordings to blindly separate the multicomponents overlapped in time and frequency domains is proposed in this paper. Based on the time varying AR model, the instantaneous frequency ... A method utilizing single channel recordings to blindly separate the multicomponents overlapped in time and frequency domains is proposed in this paper. Based on the time varying AR model, the instantaneous frequency and amplitude of each signal component are estimated respectively, thus the signal component separation is achieved. By using prolate spheroidal sequence as basis functions to expand the time varying parameters of the AR model, the method turns the problem of linear time varying parameters estimation to a linear time invariant parameter estimation problem, then the parameters are estimated by a recursive algorithm. The computation of this method is simple, and no prior knowledge of the signals is needed. Simulation results demonstrate validity and excellent performance of this method. 展开更多
关键词 time varying AR model time and frequency domains overlap single channel multi-components separation recursive algorithm
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STABILITY OF TIME VARYING SINGULAR DIFFERENTIAL SYSTEMS WITH DELAY 被引量:1
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作者 Zhang Hai1,2, Jiang Wei1 (1. School of Mathematical Sciences, Anhui University, Hefei 230039 2. School of Math. and Computation Sci., Anqing Teachers College, Anqing 246011, Anhui) 《Annals of Differential Equations》 2008年第4期484-489,共6页
In this paper, stability of time varying singular differential systems with delay is considered. Based on variation formula and Gronwall-Bellman integral inequality, we obtain the exponential estimation of the solutio... In this paper, stability of time varying singular differential systems with delay is considered. Based on variation formula and Gronwall-Bellman integral inequality, we obtain the exponential estimation of the solution and the sufficient conditions under which the considered system is stable and exponentially asymptotically stable. These results will be very useful to further research on Roust stability and control design of uncertain singular control systems with delay. 展开更多
关键词 singular differential systems with delay time varying exponential estimation STABILITY
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PGOPO Approach to Design Linear Servomechanism of Time-Varying Systems with Time-Delay
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作者 吴斌 程鹏 钟宜生 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2001年第2期88-93,共6页
Based on a new linear, continuous and bounded operator (PGOPO), a more effective approach and optimal control algorithm than by the block-pulse functions and Walsh functions to design the linear servomechanism of time... Based on a new linear, continuous and bounded operator (PGOPO), a more effective approach and optimal control algorithm than by the block-pulse functions and Walsh functions to design the linear servomechanism of time-varying systems with time-delay is proposed in the paper. By means of the operator, the differential equation is transferred to a more explicit algebraic form which is much easier than the numerical integration of nonlinear TPBVP derived from Pantryagin's maximum principle method. Furthermore, the method is established strictly based on the theory of convergence in the mean square and it is convenient and simple in computation. So the method can be applied to industry control and aeronautics and astronautics field which is frequently mixed with time varying and time delay. Some illustrative numerical examples are interpreted to support the technique. 展开更多
关键词 ALGORITHMS Convergence of numerical methods Differential equations Mathematical operators POLYNOMIALS time varying systems Walsh transforms
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Generalization of integral inequalities and (c_1,c_1) stability of neutral differential equations with time-varying delays
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作者 Shuli Guo Lina Han 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第2期347-360,共14页
A uniform stability analysis is developed for a type of neutral delays differential equations which depend on more general nonlinear integral inequalities. Many original investigations and results are obtained. Firstl... A uniform stability analysis is developed for a type of neutral delays differential equations which depend on more general nonlinear integral inequalities. Many original investigations and results are obtained. Firstly, generations of two integral nonlinear inequalities are presented, which are very effective in dealing with the complicated integro-differential inequalities whose variable exponents are greater than zero. Compared with existed integral inequalities, those proposed here can be applied to more complicated differential equations, such as time-varying delay neutral differential equations. Secondly, the notions of (ω, Ω) uniform stable and (ω, Ω) uniform asymptotically stable, especially (c1, c1) uniform stable and (c1, c1) uniform asymptotically stable, are presented. Sufficient conditions on about (c1, c1) uniform stable and (c1, c1) uniform asymptotically stable of time-varying delay neutral differential equations are established by the proposed integral inequalities. Finally, a complex numerical example is presented to illustrate the main results effectively. The above work allows to provide further applications on the proposed stability analysis and control system design for different nonlinear systems. © 2017 Beijing Institute of Aerospace Information. 展开更多
关键词 Control system stability Differential equations Nonlinear equations time delay time varying control systems
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Robust pre-specified time synchronization of chaotic systems by employing time-varying switching surfaces in the sliding mode control scheme
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作者 Alireza Khanzadeh Mahdi Pourgholi 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第8期86-93,共8页
In the conventional chaos synchronization methods, the time at which two chaotic systems are synchronized, is usually unknown and depends on initial conditions. In this work based on Lyapunov stability theory a slidin... In the conventional chaos synchronization methods, the time at which two chaotic systems are synchronized, is usually unknown and depends on initial conditions. In this work based on Lyapunov stability theory a sliding mode controller with time-varying switching surfaces is proposed to achieve chaos synchronization at a pre-specified time for the first time. The proposed controller is able to synchronize chaotic systems precisely at any time when we want. Moreover, by choosing the time-varying switching surfaces in a way that the reaching phase is eliminated, the synchronization becomes robust to uncertainties and exogenous disturbances. Simulation results are presented to show the effectiveness of the proposed method of stabilizing and synchronizing chaotic systems with complete robustness to uncertainty and disturbances exactly at a pre-specified time. 展开更多
关键词 chaos synchronization finite time synchronization sliding mode controller time varying switching surfaces
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Novel criteria for exponential synchronization of inner time-varying complex networks with coupling delay
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作者 张群娇 赵军产 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第4期145-150,共6页
This paper mainly investigates the exponential synchronization of an inner time-varying complex network with coupling delay. Firstly, the synchronization of complex networks is decoupled into the stability of the corr... This paper mainly investigates the exponential synchronization of an inner time-varying complex network with coupling delay. Firstly, the synchronization of complex networks is decoupled into the stability of the corresponding dynamical systems. Based on the Lyapunov function theory, some sufficient conditions to guarantee its stability with any given convergence rate are derived, thus the synchronization of the networks is achieved. Finally, the results are illustrated by a simple time-varying network model with a coupling delay. All involved numerical simulations verify the correctness of the theoretical analysis. 展开更多
关键词 exponential synchronization time varying complex network coupling delay
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Dynamic Stability Analysis of Linear Time-varying Systems via an Extended Modal Identification Approach 被引量:2
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作者 Zhisai MA Li LIU +3 位作者 Sida ZHOU Frank NAETS Ward HEYLEN Wim DESMET 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第2期459-471,共13页
The problem of linear time-varying(LTV) system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system mo... The problem of linear time-varying(LTV) system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system modal analysis under the "frozen-time" assumption are not able to determine the dynamic stability of LTV systems. Time-dependent state space representations of LTV systems are first introduced, and the corresponding modal analysis theories are subsequently presented via a stabilitypreserving state transformation. The time-varying modes of LTV systems are extended in terms of uniqueness, and are further interpreted to determine the system's stability. An extended modal identification is proposed to estimate the time-varying modes, consisting of the estimation of the state transition matrix via a subspace-based method and the extraction of the time-varying modes by the QR decomposition. The proposed approach is numerically validated by three numerical cases, and is experimentally validated by a coupled moving-mass simply supported beam exper- imental case. The proposed approach is capable of accurately estimating the time-varying modes, and provides anew way to determine the dynamic stability of LTV systems by using the estimated time-varying modes. 展开更多
关键词 Linear time·varying systems · Extended modal identification · Dynamic stability analysis · time·varying modes
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Universal Adaptive Observerfor Nonlinear Time varying Deterministic Systems
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作者 周东华 金以慧 《Tsinghua Science and Technology》 SCIE EI CAS 1999年第4期1597-1601,共5页
Designing adaptive observers for MIMO nonlinear time varying deterministic systems is an open problem .Inthis papera novelsolutiontothis problem is given byuse ofa “strongtrackingfilter(STF)”.First,the STFis outl... Designing adaptive observers for MIMO nonlinear time varying deterministic systems is an open problem .Inthis papera novelsolutiontothis problem is given byuse ofa “strongtrackingfilter(STF)”.First,the STFis outlined,then sometechnicalpoints ofview to usethe STFas an adaptive observer are discussed .Finally, two typicalexamples are presentedtoillustrate the effectiveness ofthe proposed approach. 展开更多
关键词 nonlinearsystem time varying system strongtrackingfilter adaptive observer
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