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Reliability Analysis of Correlated Competitive and Dependent Components Considering Random Isolation Times
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作者 Shuo Cai Tingyu Luo +3 位作者 Fei Yu Pradip Kumar Sharma Weizheng Wang Lairong Yin 《Computers, Materials & Continua》 SCIE EI 2023年第9期2763-2777,共15页
In the Internet of Things(IoT)system,relay communication is widely used to solve the problem of energy loss in long-distance transmission and improve transmission efficiency.In Body Sensor Network(BSN)systems,biosenso... In the Internet of Things(IoT)system,relay communication is widely used to solve the problem of energy loss in long-distance transmission and improve transmission efficiency.In Body Sensor Network(BSN)systems,biosensors communicate with receiving devices through relay nodes to improve their limited energy efficiency.When the relay node fails,the biosensor can communicate directly with the receiving device by releasing more transmitting power.However,if the remaining battery power of the biosensor is insufficient to enable it to communicate directly with the receiving device,the biosensor will be isolated by the system.Therefore,a new combinatorial analysis method is proposed to analyze the influence of random isolation time(RIT)on system reliability,and the competition relationship between biosensor isolation and propagation failure is considered.This approach inherits the advantages of common combinatorial algorithms and provides a new approach to effectively address the impact of RIT on system reliability in IoT systems,which are affected by competing failures.Finally,the method is applied to the BSN system,and the effect of RIT on the system reliability is analyzed in detail. 展开更多
关键词 BSN Internet of Things reliability analysis random isolation time
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Evaluation of Freeway Travel Time Variability and Reliability under Adverse Weather with TRANSMIT Data 被引量:3
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《Journal of Civil Engineering and Architecture》 2012年第1期1-11,共11页
Traffic congestion has caused many detrimental effects including higher fuel consumption, more vehicle emissions, increased accidents, as well as greater tension due to uncertain travel time. In addition to delay, the... Traffic congestion has caused many detrimental effects including higher fuel consumption, more vehicle emissions, increased accidents, as well as greater tension due to uncertain travel time. In addition to delay, the variability and reliability of travel time has been of concern to motorists on their daily travel, especially during peak periods. The objective of this study is to examine freeway travel time variability and reliability under different traffic and weather conditions with the use of TRANSMIT data collected by roadside readers deployed on a 40-mile segment of the Interstate Highway 1-287 in New Jersey. Travel time variability and reliability measures including mean travel time, the 95th percentile travel time, travel time index, buffer index, and planning time index under recurring and non-recurring congestion (adverse weather) are investigated. It was found that the standard deviation of travel time increased, due to the weather condition varying from dry to rain and to snow, while the buffer index increased from 29% to 45% and to 94%. 展开更多
关键词 Travel time VARIABILITY reliability TRANSMIT ITS traveler information.
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Time-variant fragility analysis of the bridge system considering time-varying dependence among typical component seismic demands 被引量:6
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作者 Song Shuai Qian Yongjiu +2 位作者 Liu Jing Xie Xiaorui Wu Gang 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2019年第2期363-377,共15页
This paper presents a copula technique to develop time-variant seismic fragility curves for corroded bridges at the system level and considers the realistic time-varying dependence among component seismic demands. Bas... This paper presents a copula technique to develop time-variant seismic fragility curves for corroded bridges at the system level and considers the realistic time-varying dependence among component seismic demands. Based on material deterioration mechanisms and incremental dynamic analysis, the time-evolving seismic demands of components were obtained in the form of marginal probability distributions. The time-varying dependences among bridge components were then captured with the best fitting copula function, which was selected from the commonly used copula classes by the empirical distribution based analysis method. The system time-variant fragility curves at different damage states were developed and the effects of time-varying dependences among components on the bridge system fragility were investigated. The results indicate the time-varying dependence among components significantly affects the time-variant fragility of the bridge system. The copula technique captures the nonlinear dependence among component seismic demands accurately and easily by separating the marginal distributions and the dependence among them. 展开更多
关键词 system FRAGILITY CHLORIDE corrosion time-varying DEPENDENCE COPULA function probabilistic seismic demand
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Sample-data Decentralized Reliable H∞ Hyperbolic Control for Uncertain Fuzzy Large-scale Systems with Time-varying Delay 被引量:2
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作者 LIU Xin-Rui ZHANG Hua-Guang 《自动化学报》 EI CSCD 北大核心 2009年第12期1534-1540,共7页
这份报纸学习样品数据的问题为有变化时间的延期的不明确的连续时间的模糊大规模系统的可靠 H 夸张控制。第一,模糊夸张模型( FHM )被用来为某些复杂大规模系统建立模型,然后根据 Lyapunov 指导方法和大规模系统的分散的控制理论,线... 这份报纸学习样品数据的问题为有变化时间的延期的不明确的连续时间的模糊大规模系统的可靠 H 夸张控制。第一,模糊夸张模型( FHM )被用来为某些复杂大规模系统建立模型,然后根据 Lyapunov 指导方法和大规模系统的分散的控制理论,线性 matrixine 质量( LMI )基于条件 arederived toguarantee H 性能不仅当所有控制部件正在操作很好时,而且面对一些可能的致动器失败。而且,致动器的精确失败参数没被要求,并且要求仅仅是失败参数的更低、上面的界限。条件依赖于时间延期的上面的界限,并且不依赖于变化时间的延期的衍生物。因此,获得的结果是不太保守的。最后,二个例子被提供说明设计过程和它的有效性。 展开更多
关键词 模糊双曲模型 线性矩阵不等式 分散控制理论 执行器
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RELIABILITY ANALYSIS FOR A REPAIRABLE PARALLEL SYSTEM WITH TIME-VARYING FAILURE RATES 被引量:1
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作者 TangShengdao WangFengquan 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2005年第1期85-90,共6页
To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,... To solve a real problem:how to calculate the reliability of a system with time-varying failure rates in industry systems,this paper studies a model for the load-sharing parallel system with time-varying failure rates,and obtains calculating formulas of reliability and availability of the system by solving differential equations.In this paper,the failure rates are expressed in polynomial configuration.The constant,linear and Weibull failure rate are in their special form.The polynomial failure rates provide flexibility in modeling the practical time-varying failure rates. 展开更多
关键词 time-varying failure rates repairable parallel system Markov chain reliability and availability of system load-sharing.
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GENERAL DECAY FOR A VISCOELASTIC EQUATION OF VARIABLE COEFFICIENTS WITH A TIME-VARYING DELAY IN THE BOUNDARY FEEDBACK AND ACOUSTIC BOUNDARY CONDITIONS 被引量:3
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作者 Vamna BOUKHATEM Benyattou BENABDERRAHMANE 《Acta Mathematica Scientia》 SCIE CSCD 2017年第5期1453-1471,共19页
A variable coefficient viscoelastic equation with a time-varying delay in the boundary feedback and acoustic boundary conditions and nonlinear source term is considered.Under suitable assumptions, general decay result... A variable coefficient viscoelastic equation with a time-varying delay in the boundary feedback and acoustic boundary conditions and nonlinear source term is considered.Under suitable assumptions, general decay results of the energy are established via suitable Lyapunov functionals and some properties of the convex functions. Our result is obtained without imposing any restrictive growth assumption on the damping term and the elements of the matrix A and the kernel function g. 展开更多
关键词 acoustic boundary conditions general decay time-varying delay variable coefficients viscoelastic equation
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Adaptive Variable Structure Control of MIMO Nonlinear Systems with Time-varying Delays and Unknown Dead-zones 被引量:7
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作者 Tian-Ping Zhang Cai-Ying Zhou Qing Zhu 《International Journal of Automation and computing》 EI 2009年第2期124-136,共13页
In this paper, adaptive variable structure neural control is presented for a class of uncertain multi-input multi-output (MIMO) nonlinear systems with state time-varying delays and unknown nonlinear dead-zones. The ... In this paper, adaptive variable structure neural control is presented for a class of uncertain multi-input multi-output (MIMO) nonlinear systems with state time-varying delays and unknown nonlinear dead-zones. The unknown time-varying delay uncer- tainties are compensated for using appropriate Lyapunov-Krasovskii functionals in the design. The approach removes the assumption of linear function outside the deadband without necessarily constructing a dead-zone inverse as an added contribution. By utilizing the integral-type Lyapunov function and introducing an adaptive compensation term for the upper bound of the residual and optimal approximation error as well as the dead-zone disturbance, the closed-loop control system is proved to be semi-globally uniformly ultimately bounded. In addition, a modified adaptive control algorithm is given in order to avoid the high-frequency chattering phenomenon. Simulation results demonstrate the effectiveness of the approach. 展开更多
关键词 Adaptive control neural networks (NNs) variable structure control DEAD-ZONE nonlinear time-varying delay systems.
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Time-Variant Reliability Analysis of FPSO Hull Girder Considering Corrosion Based on Statistics 被引量:2
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作者 张道坤 唐文勇 张圣坤 《China Ocean Engineering》 SCIE EI 2007年第2期197-205,共9页
FPSO is a kind of important exploitation platform used in ocean oil and gas industry, which has the unique character of mooring at outsea for a long time. Since it can not be inspected and maintained thoronghly at doc... FPSO is a kind of important exploitation platform used in ocean oil and gas industry, which has the unique character of mooring at outsea for a long time. Since it can not be inspected and maintained thoronghly at dock like other kinds of ships, the reliability of FPSO hull girder during the whole service should be focused. Based on latest corrosion database and rational corrosion model, the ultimate strength of one FPSO is calculated under the conditions of slight, moderate and severe corrosion. The results not only provide the reliabihty under different corrosion conditions, but also do well for further inspection and maintenance research. The results provide necessary foundation for deciding inspection intervals and maintenance measure, which has practical sense to improve the general safety level of ocean engineering. 展开更多
关键词 FPSO CORROSION time-variant reliability analysis
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Partial Time-Varying Coefficient Regression and Autoregressive Mixed Model
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作者 Hui Li Zhiqiang Cao 《Open Journal of Statistics》 2023年第4期514-533,共20页
Regression and autoregressive mixed models are classical models used to analyze the relationship between time series response variable and other covariates. The coefficients in traditional regression and autoregressiv... Regression and autoregressive mixed models are classical models used to analyze the relationship between time series response variable and other covariates. The coefficients in traditional regression and autoregressive mixed models are constants. However, for complicated data, the coefficients of covariates may change with time. In this article, we propose a kind of partial time-varying coefficient regression and autoregressive mixed model and obtain the local weighted least-square estimators of coefficient functions by the local polynomial technique. The asymptotic normality properties of estimators are derived under regularity conditions, and simulation studies are conducted to empirically examine the finite-sample performances of the proposed estimators. Finally, we use real data about Lake Shasta inflow to illustrate the application of the proposed model. 展开更多
关键词 Regression and Autoregressive time Series Partial time-varying Coefficient Local Polynomial
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Partial Time-Varying Coefficient Regression and Autoregressive Mixed Model
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作者 Hui Li Zhiqiang Cao 《Open Journal of Endocrine and Metabolic Diseases》 2023年第4期514-533,共20页
Regression and autoregressive mixed models are classical models used to analyze the relationship between time series response variable and other covariates. The coefficients in traditional regression and autoregressiv... Regression and autoregressive mixed models are classical models used to analyze the relationship between time series response variable and other covariates. The coefficients in traditional regression and autoregressive mixed models are constants. However, for complicated data, the coefficients of covariates may change with time. In this article, we propose a kind of partial time-varying coefficient regression and autoregressive mixed model and obtain the local weighted least-square estimators of coefficient functions by the local polynomial technique. The asymptotic normality properties of estimators are derived under regularity conditions, and simulation studies are conducted to empirically examine the finite-sample performances of the proposed estimators. Finally, we use real data about Lake Shasta inflow to illustrate the application of the proposed model. 展开更多
关键词 Regression and Autoregressive time Series Partial time-varying Coefficient Local Polynomial
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The time and frequency system of the Tianma 65 m radio telescope
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作者 Lingling Wang Qinghui Liu Yong Cai 《Astronomical Techniques and Instruments》 CSCD 2024年第5期260-266,共7页
A time and frequency system is a critical component of Very Long Baseline Interferometry(VLBI)stations,providing stable and reliable standards that directly impact data processing quality.At the Tianma 65 m radio tele... A time and frequency system is a critical component of Very Long Baseline Interferometry(VLBI)stations,providing stable and reliable standards that directly impact data processing quality.At the Tianma 65 m radio telescope(TMRT),this system has been meticulously designed to ensure long-term reliability and high performance.It incorporates high-performance hydrogen atomic clocks,high-precision time standards,automatic signal switching,and robust system software.This comprehensive approach has enabled the system to achieve long-term reliable operation,successfully supporting both major national engineering tasks and daily scientific observations.The effectiveness of the system is evidenced by its consistent delivery of the precision and stability required for radio astronomy.This article provides an in-depth exploration of the design and operation of the time and frequency system at the Tianma 65 m telescope,examining various aspects of its architecture,implementation,and performance.By sharing these insights,we aim to contribute knowledge that could benefit similar systems at other VLBI stations,greatly advancing radio astronomy infrastructure. 展开更多
关键词 time and frequency system Hydrogen atomic clock reliability
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Methods for Reliability Assessment under Irregular Time-Varying-Stress Degradation Testing
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作者 刘天宇 孙权 +1 位作者 潘正强 冯静 《Journal of Donghua University(English Edition)》 EI CAS 2014年第6期793-795,共3页
Degradation tests are often used to assess the reliability of products with long failure-time or few test units. Much of the previous work on reliability assessment methods has focused on constant-stress degradation t... Degradation tests are often used to assess the reliability of products with long failure-time or few test units. Much of the previous work on reliability assessment methods has focused on constant-stress degradation test( CSDT) and accelerated degradation test( ADT), mainly under the constant, step or progressive stresses. However,in actual testing environments,some stresses are difficult to control and vary with time irregularly,which are quite different from the three stresses mentioned above. In this paper a new approach was presented for reliability assessment with degradation data under irregular time-varying-stress( ITVS).Firstly,the conventional degradation path modeling method was improved by taking into account the influences of the variable stress on the degradation variable. Then,an example was conducted to show the effectiveness of our improved model. 展开更多
关键词 reliability assessment irregular time-varying-stress(ITVS) degradation test degradation path modeling
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A Simulation Study on Comparing General Class of Semiparametric Transformation Models for Survival Outcome with Time-Varying Coefficients and Covariates
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作者 Yemane Hailu Fissuh Tsegay Giday Woldu +1 位作者 Idriss Abdelmajid Idriss Ahmed Abebe Zewdie Kebebe 《Open Journal of Statistics》 2019年第2期169-180,共12页
The consideration of the time-varying covariate and time-varying coefficient effect in survival models are plausible and robust techniques. Such kind of analysis can be carried out with a general class of semiparametr... The consideration of the time-varying covariate and time-varying coefficient effect in survival models are plausible and robust techniques. Such kind of analysis can be carried out with a general class of semiparametric transformation models. The aim of this article is to develop modified estimating equations under semiparametric transformation models of survival time with time-varying coefficient effect and time-varying continuous covariates. For this, it is important to organize the data in a counting process style and transform the time with standard transformation classes which shall be applied in this article. In the situation when the effect of coefficient and covariates change over time, the widely used maximum likelihood estimation method becomes more complex and burdensome in estimating consistent estimates. To overcome this problem, alternatively, the modified estimating equations were applied to estimate the unknown parameters and unspecified monotone transformation functions. The estimating equations were modified to incorporate the time-varying effect in both coefficient and covariates. The performance of the proposed methods is tested through a simulation study. To sum up the study, the effect of possibly time-varying covariates and time-varying coefficients was evaluated in some special cases of semiparametric transformation models. Finally, the results have shown that the role of the time-varying covariate in the semiparametric transformation models was plausible and credible. 展开更多
关键词 Estimating Equation SEMIPARAMETRIC Transformation Models time-TO-EVENT Outcomes time-varying COEFFICIENTS time-varying COVARIATE
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Sufficient conditions of the various stabilities of the linear time-varying delayed differential equations
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作者 Lijun Pei 《Theoretical & Applied Mechanics Letters》 CAS 2013年第6期59-61,共3页
Due to the appearance and the study of the ornithopter and flexible-wing micro air vehicles, etc., the time-varying systems become more and more important and ubiquitous in the study of the mechanics. In this letter, ... Due to the appearance and the study of the ornithopter and flexible-wing micro air vehicles, etc., the time-varying systems become more and more important and ubiquitous in the study of the mechanics. In this letter, the sufficient conditions of the uniform asymptotic stability are first presented for the delayed time-varying linear differential equations with any time delay by employing the Dini derivative, Lozinskii measure and the generalized scalar Halanay delayed differential inequality. They are especially based on the estimation of the arbitrary solutions but not the fundamental solution matrix since their solutions' space is infinite-dimensional. Then some sufficient conditions of the stability, asymptotic stability and uniform asymptotic stability of the delayed time-varying linear system with a sufficiently small time delay are reported by employing Taylor expansion and Dini derivative. It implies that these stabilities can be guaranteed by the Lozinskii measure of the matrix composing of the time delay and the coefficient matrices of the system. 展开更多
关键词 sufficient conditions STABILITY uniform asymptotic stability time delay time-varying linearsystem
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Invariant operator theory for the single-photon energy in time-varying media
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作者 Choi Jeong-Ryeol 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第1期56-60,共5页
After the birth of quantum mechanics, the notion in physics that the frequency of light is the only factor that determines the energy of a single photon has played a fundamental role. However, under the assumption tha... After the birth of quantum mechanics, the notion in physics that the frequency of light is the only factor that determines the energy of a single photon has played a fundamental role. However, under the assumption that the theory of Lewis-Riesenfeld invariants is applicable in quantum optics, it is shown in the present work that this widely accepted notion is valid only for light described by a time-independent Hamiltonian, i.e., for light in media satisfying the conditions, ε(t) = ε(0), u(t) = u(0), and σ(t) = 0 simultaneously. The use of the Lewis Riesenfeld invariant operator method in quantum optics leads to a marvelous result: the energy of a single photon propagating through time-varying linear media exhibits nontrivial time dependence without a change of frequency. 展开更多
关键词 single-photon energy invariant operator theory time-varying media
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Properties of Time-Varying Causality Tests in the Presence of Multivariate Stochastic Volatility
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作者 Daiki Maki 《Open Journal of Statistics》 2016年第5期777-788,共13页
This paper compares the statistical properties of time-varying causality tests when errors of variables have multivariate stochastic volatility (SV). The time-varying causal-ity tests in this paper are based on a logi... This paper compares the statistical properties of time-varying causality tests when errors of variables have multivariate stochastic volatility (SV). The time-varying causal-ity tests in this paper are based on a logistic smooth transition autoregressive model. The compared time-varying causality tests include asymptotic tests, heteroskedasticity-robust tests, and tests using wild bootstrap. Our simulation results show that asymptotic tests and heteroskedasticity-robust counterparts have size distortions under multivariate SV, whereas tests using wild bootstrap have better size properties regardless of type of error. In particular, the time-varying causality test with first-order Taylor approximation using wild bootstrap has better statistical properties. 展开更多
关键词 time-varying Causality Tests Wild Bootstrap Multivariate Stochastic Volatility
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Bus transit travel time reliability evaluation based on automatic vehicle location data 被引量:4
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作者 严亚丹 过秀成 +2 位作者 李岩 孔哲 何明 《Journal of Southeast University(English Edition)》 EI CAS 2012年第1期100-105,共6页
In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed a... In order to provide important parameters for schedule designing, decision-making bases for transit operation management and references for passengers traveling by bus, bus transit travel time reliability is analyzed and evaluated based on automatic vehicle location (AVL) data. Based on the statistical analysis of the bus transit travel time, six indices including the coefficient of variance, the width of travel time distribution, the mean commercial speed, the congestion frequency, the planning time index and the buffer time index are proposed. Moreover, a framework for evaluating bus transit travel time reliability is constructed. Finally, a case study on a certain bus route in Suzhou is conducted. Results show that the proposed evaluation index system is simple and intuitive, and it can effectively reflect the efficiency and stability of bus operations. And a distinguishing feature of bus transit travel time reliability is the temporal pattern. It varies across different time periods. 展开更多
关键词 bus transit travel time reliability evaluation andanalysis automatic vehicle location data statistical analysis
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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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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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