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Dissertations / Theses on the topic 'Discrete-time systems'
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Jerbi, Ali. "Adaptive control of time-varying discrete-time systems." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/15743.
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Walker, Daniel James. "Robust control of discrete time systems." Thesis, Imperial College London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321140.
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El-Bialy, Ahmed Mohamed. "Control of multiplicative discrete-time systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=case1055262732.
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Haddleton, Steven W. "Steady-state performance of discrete linear time-invariant systems /." Online version of thesis, 1994. http://hdl.handle.net/1850/11795.
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Lawford, Mark Stephen. "Model reduction of discrete real-time systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ27988.pdf.
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Dan-Isa, Ado. "Discrete-time design for computer controlled systems." Thesis, University of Sussex, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283145.
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Zhao, Yong 1980. "Discrete-time observers for inertial navigation systems." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17956.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (p. 65-66).
In this thesis, we derive an exact deterministic nonlinear observer to compute the continuous-time states of inertial navigation system based on partial discrete measurements, the so-called strapdown problem. Nonlinear contraction theory is used as the main analysis tool. The hierarchical structure of the system physics is sytematically exploited and the use of nonlinear measurements, such as distances to time-varying reference points, is discussed. Effects of bounded errors on model and measurements are quantified, and can be used for active measurement selection. Work on vehicle state computation is carried out by using a similar observer design method. Finally, the approach is used to compute the head orientation of a simulated planar hopping robot, where the information provided by the observer is used for head stabilization and obstacle jump.
by Yong Zhao.
S.M.
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Dale, Wilbur Nolan. "Stabilization and robust stability of discrete-time, time- varying systems /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487694389393404.
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Riffer, Jennifer Lynn. "Time-optimal control of discrete-time systems with known waveform disturbances." [Milwaukee, Wis.] : e-Publications@Marquette, 2009. http://epublications.marquette.edu/theses_open/18.
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Iglesias, Pablo Alberto. "Robust and adaptive control for discrete-time systems." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386123.
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Field, Christopher Michael. "On the quantization of integrable discrete-time systems." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417895.
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Barth, Eric J. "Approximating infinite horizon discrete-time optimal control using CMAC networks." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/19464.
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Hayakawa, Yoshikazu, and Tomohiko Jimbo. "Floquet Transformations for Discrete-time Systems: Equivalence between periodic systems and time-invariant ones." IEEE, 2008. http://hdl.handle.net/2237/12125.
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Gupta, Amit. "Model reduction and simulation of complex dynamic systems /." Online version of thesis, 1990. http://hdl.handle.net/1850/11265.
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Hayakawa, Yoshikazu, and Tomohiko Jimbo. "Transformability from discrete-time periodic non-homogeneous systems to time-invariant ones." IEEE, 2009. http://hdl.handle.net/2237/13935.
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Jamak, Anes. "Stabilization of Discrete-time Systems With Bounded Control Inputs." Thesis, University of Waterloo, 2000. http://hdl.handle.net/10012/765.
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In this paper we examine the stabilization of LTI discrete-time systems with control input constraints in the form of saturation nonlinearities. This kind of constraint is usually introduced to simulate the effect of actuator limitations. Since global controllability can not be assumed in the presence of constrained control, the controllable regions and their characterizations are analyzed first. We present an efficient algorithm for finding controllable regions in terms of their boundary hyperplanes (inequality constraints). A previously open question about the exact number of irredundant boundary hyperplanes is also resolved here. The main result of this research is a time-optimal nonlinear controller which stabilizes the system on its controllable region. We give analgorithm for on-line computation of control which is also implementable for high-order systems. Simulation results show superior response even in the presence of disturbances.
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Lu, Jianqiu. "Stabilization of hybrid systems by discrete-time feedback controls." Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=30379.
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Hybrid stochastic differential equations (SDEs) (also known as SDEs with Markovian switching) have been used to model many practical systems where they may experience abrupt changes in their structure and parameters. One of the important issues in the study of hybrid systems is the automatic control, with consequent emphasis being placed on the asymptotic analysis of stability. One classical topic in this field is the problem of stabilization. The stability of hybrid systems by feedback control based on continuous-time observations has been studied extensively in the past decades. Recently, Mao [52] initiates the study on the mean-square exponential stabilization of continuous-time hybrid stochastic differential equations by feedback controls based on discrete-time state observations. Mao [52] also obtains an upperbound on the duration between two consecutive state observations. However, it is due to the general technique used there that the bound on is not very sharp. In this thesis, we will consider a couple of important classes of hybrid SDEs. Making full use of their special features, we will be able to establish a better bound on. Our new theory enables us to observe the system state less frequently (so costless) but still to be able to design the feedback control based on the discrete-timestate observations to stabilize the given hybrid SDEs in the sense of mean-square exponential stability. Moreover, we will be able to establish a better bound on making use of Lyapunov functionals. By this method, we will not only discuss the stabilization in the sense of exponential stability but also in other sense of H1 stability or asymptotic stability as well. We will not only consider the mean square stability but also the almost sure stability. It is easy to observe that the feedback control there still depends on the continuous-time observations of the mode. However, it usually costs to identify the current mode of the system in practice. So we can further improve the control to reduce the control cost by identifying the mode at discrete times when we make observations for the state. Therefore, we will also design such a type of feedback control based on the discrete-time observations of both state and mode to stabilize the given hybrid stochastic differential equations (SDEs) in the sense of mean-square exponential stability in this thesis. Similarly, we can extend our discussion to the stabilization of continuous-time hybrid stochastic differential equations by feedback controls based on not only discrete-time state observations but also discrete-time mode observations by Lyapunov method. At last, we will investigate stability of Stochastic differential delay equations with Markovian switching by feedback control based on discrete-time State and mode observations by using Lyapunov functional. Hence, we will get the upperbound on the duration between two consecutive state and mode observations.
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Hall, Charles Edward. "Formulation and minimality of nonlinear discrete time control systems /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487266011222429.
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Rotstein, Hector P. Sideris Athanasios. "Constrained HP [infinity]-optimization for discrete-time control systems /." Diss., Pasadena, Calif. : California Institute of Technology, 1993. http://resolver.caltech.edu/CaltechETD:etd-11282007-130457.
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Göl, Ebru Aydin. "Formal verification and controller synthesis for discrete-time systems." Thesis, Boston University, 2014. https://hdl.handle.net/2144/10934.
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Thesis (Ph.D.)--Boston UniversityTemporal logics, such as Computation Tree Logic (CTL) and Linear Temporal Logic (LTL), are customarily used to specify the correctness of computer programs and digital circuits modeled as finite-state transition systems. In recent years, due to their expressivity and resemblance to natural language, temporal logics gained increasing popularity as specification languages for more realistic system models, such as dynamical systems. Most of the work approaching the problem of verifying and controlling non-trivial dynamical systems from rich specifications are centered on the concept of abstraction. This dissertation proposes theoretical frameworks and computational tools for the verification and control of continuous-state discrete-time systems from temporal logic specifications. The focus of this dissertation is on three particular classes of discrete-time systems, with widespread use in several areas: linear, switched linear, and piecewise affine systems. For switched linear systems, the existence of equivalent finite models is shown under stability constraints. Efficient algorithms to compute such finite models are developed. Moreover, algorithms for solving verification and synthesis problems from formulae of a particular fragment of LTL are designed, and are applied to equivalent finite models of stable switched linear systems. For linear and piecewise affine systems, a novel language-guided procedure to design control strategies from temporal logic specifications is developed. The language-guided procedure combines the abstraction and temporal logic control of the finite model, and restricts the search for control strategies in such a way that the satisfaction of the specifications is guaranteed at all times. Furthermore, this procedure generates a characterization of all satisfying system trajectories in the form of sequences of polytopic sets, which allows synthesizing optimal control strategies from temporal logic specifications. In particular, a model predictive control (MPC) approach for optimal control of piecewise affine systems from temporal logic specifications is proposed. The MPC controller minimizes a cost over the trajectories of the system, while guaranteeing correctness with respect to a temporal logic formula. As an application, a computational framework for formal verification of synthetic gene networks from given experimental data is presented.
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Lahijanian, Morteza M. "Formal verification and control of discrete-time stochastic systems." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12804.
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Thesis (Ph.D.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.This thesis establishes theoretical and computational frameworks for formal verification and control synthesis for discrete-time stochastic systems. Given a temporal logic specification, the system is analyzed to determine the probability that the specification is achieved, and an input law is automatically generated to maximize this probability. The approach consists of three main steps: constructing an abstraction of the stochastic system as a finite Markov model, mapping the given specification onto this abstraction, and finding a control policy to maximize the probability of satisfying the specification. The framework uses Probabilistic Computation Tree Logic (PCTL) as the specification language. The verification and synthesis algorithms are inspired by the field of probabilistic model checking. In abstraction, a method for the computation of the exact transition probability bounds between the regions of interest in the domain of the stochastic system is first developed. These bounds are then used to construct an Interval-valued Markov Chain (IMC) or a Bounded-parameter Markov Decision Process (BMDP) abstraction for the system. Then, a representative transition probability is used to construct an approximating Markov chain (MC) for the stochastic system. The exact bound of the approximation error and an explicit expression for its grovvth over time are derived. To achieve a desired error value, an adaptive refinement algorithm that takes advantage of the linear dynamics of the system is employed. To verify the properties of the continuous domain stochastic system against a finite-time PCTL specification, IMC and BMDP verification algorithms are designed. These algorithms have low computational complexity and are inspired by the MC model checking algorithms. The low computational complexity is achieved by over approximating the probabilities of satisfaction. To increase the precision of the method, two adaptive refinement procedures are proposed. Furthermore, a method of generating the control strategy that maximizes the probability of satisfaction of a PCTL specification for Markov Decision Processes (MDPs) is developed. Through a similar method, a formal synthesis framework is constructed for continuous domain stochastic systems by utilizing their BMDP abstractions. These methodologies are then applied in robotics applications as a means of automatically deploying a mobile robot subject to noisy sensors and actuators from PCTL specifications. This technique is demonstrated through simulation and experimental case studies of deployment of a robot in an indoor environment. The contributions of the thesis include verification and synthesis frameworks for discrete time stochastic linear systems, abstraction schemes for stochastic systems to MCs, IMCs, and BMDPs, model checking algorithms with low computational complexity for IMCs and BMDPs against finite-time PCTL formulas, synthesis algorithms for Markov Decision Processes (MDPs) from PCTL formulas, and a computational framework for automatic deployment of a mobile robot from PCTL specifications. The approaches were validated by simulations and experiments. The algorithms and techniques in this thesis help to make discrete-time stochastic systems a more useful and effective class of models for analysis and control of real world systems.
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Milonidis, E. "Finite settling time stabilization for linear multivariable time-invariant discrete-time systems : an algebraic approach." Thesis, City University London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259928.
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Lee, Keh-ning. "Discrete-time adaptive control of a class of nonlinear systems /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487267024997294.
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Wang, Chao, and 王超. "Statistical inference for some discrete-valued time series." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48329514.
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Some problems of' statistical inference for discrete-valued time series are investigated in this study. New statistical theories and methods are developed which may aid us in gaining more insight into the understanding of discrete-valued time series data.
The first part is concerned with the measurement of the serial dependence of binary time series. In early studies the classical autocorrelation function was used, which, however, may not be an effective and informative means of revealing the dependence feature of a binary time series. Recently, the autopersistence function has been proposed as an alternative to the autocorrelation function for binary time series. The theoretical autopersistence functions and their sample analogues, the autopersistence graphs, are studied within a binary autoregressive model. Some properties of the autopcrsistencc functions and the asymptotic properties of the autopersistence graphs are discussed, justifying that the antopersistence graphs can be used to assess the dependence feature.
Besides binary time series, intcger-vall1ed time series arc perhaps the most commonly seen discrete-valued time series. A generalization of the Poisson autoregression model for non-negative integer-valued time series is proposed by imposing an additional threshold structure on the latent mean process of the Poisson autoregression. The geometric ergodicity of the threshold Poisson autoregression with perburbations in the latent mean process and the stochastic stability of the threshold Poisson autoregression are obtained. The maximum likelihood estimator for the parameters is discussed and the conditions for its consistency and asymptotic normally are given as well.
Furthermore, there is an increasing need for models of integer-valued time series which can accommodate series with negative observations and dependence structure more complicated than that of an autoregression or a moving average. In this regard, an integer-valued autoregressive moving average process induced by the so-called signed thinning operator is proposed. The first-order model is studied in detail. The conditions for the existence of stationary solution and the existence of finite moments are discussed under general assumptions. Under some further assumptions about the signed thinning operators and the distribution of the innovation, a moment-based estimator for the parameters is proposed, whose consistency and asymptotic normality are also proved. The problem of conducting one-step-ahead forecast is also considered based on hidden Markov chain theory.
Simulation studies arc conducted to demonstrate the validity of the theories and methods established above. Real data analysis such as the annual counts of major earthquakes data are also presented to show their potential usefulness in applications.published_or_final_version
Statistics and Actuarial Science
Doctoral
Doctor of Philosophy
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El-Shafey, Mohamed Hassan. "Linear continuous-time system identification and state observer design by modal analysis." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/28666.
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A new approach to the identification problem of linear continuous-time time-invariant systems from input-output measurements is presented. Both parametric and nonparametric system models are considered. The new approach is based on the use of continuous-time functions, the modal functions, defined in terms of the system output, the output derivatives and the state variables under the assumption that the order n of the observable system is known a priori. The modal functions are obtained by linear filtering operations of the system output, the output derivatives
and the state variables so that the modal functions are independent of the system instantaneous state. In this case, the modal functions are linear functions of the input exponential modes, and they contain none of the system exponential modes unlike the system general response which contains modes from both the system
and the input. The filters parameters, the modal parameters are estimated using linear regression techniques.
The modal functions and the modal parameters of the output and its derivatives
are used to identify parametric input-output and state models of the system. The coefficients of the system characteristic polynomial are obtained by solving n algebraic equations formed from the estimates of the modal parameters. Estimates
of the parameters associated with the system zeros are obtained by solving another set of linear algebraic equation. The system frequency response and step response are estimated using the output modal function. The impulse response is obtained by filtering the estimated step response using the output first derivative modal parameters.
A new method is presented to obtain the system poles as the eigenvalues of a data matrix formed from the system free response. The coefficients of the system characteristic polynomial are obtained from the data matrix through a simple recursive
equation. This method has some important advantages over the well known Prony's method.
The state modal functions are used to obtain a minimum-time observer that gives the continuous-time system state as a direct function of input-output samples in n sampling intervals.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Smith, Ian David. "A unifying framework for model reduction by least-squares Padé approximation." Thesis, Abertay University, 1998. https://rke.abertay.ac.uk/en/studentTheses/825b9932-2bf7-4ad1-a0c7-d658b44e235a.
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A thorough review of the literature on the model reduction of linear, time-invariant, dynamical systems in both the frequency and time domains is presented. Particular attention is paid to the least-squares extension of the classical method of Padé approximation. An account is given of the development of apparently different approaches of least-squares parameter- matching Padé model reduction applied to continuous-time and discrete-time systems. These approaches are shown to be related via a unifying theory. From the formulation it is possible to show several interesting features of the least-squares approach which lead to a fuller understanding of exactly how the reduced model approximates the full system. An error index is derived in the general continuous-time case and it is shown that a range of system parameter preservation options are available. Using the theory developed in the continuous-time case a non-uniqueness property of the method is proven. An ‘optimal’ least-squares method based on the approach and the introduction of weighting for the system parameters are both investigated. The unifying theory is extended to the discrete-time case where an important new stability preservation property is proved and is shown to provide the basis for a new least- squares Padé method. This method uses transformations between the z- and 5-planes to guarantee stable reduced order models approximating stable high order continuous-time systems. The application of least-squares Padé approximation is further extended to the multivariable case with particular attention given to the factors affecting the levels of order reduction achieved. Appropriate numerical examples are used to illustrate the main points of the thesis and graphs of the impulse and step responses are used throughout to visually highlight the accuracy of approximation.
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Kebede, Dawit. "An effective discontinuity handling method for hybrid continuous-time/discrete-time systems simulation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0008/MQ29998.pdf.
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Eliiyi, Ugur. "Discrete-time Stochastic Analysis Of Land Combat." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/759472/index.pdf.
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In this study, we present the implementation and experimental analysis of a modeling approach for analyzing tactical level land combat to generate information for weapon and ammunition planning. The discrete-time stochastic model (DSM), which can handle small and moderately large force levels, is based on single shot kill probabilities. Forces are assumed to be heterogeneous on both sides, and both directed and area fire types are modeled by means of combinatorial analysis. DSM considers overkills and can handle noncombat loss and engagement processes, discrete reinforcements, force combinations and divisions. In addition to experimenting with DSM, we estimate attrition rate coefficients used in Lanchester combat models, such that the two models will yield similar figures for force levels throughout the combat.
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Wan, Jian. "Computationally reliable approaches of contractive MPC for discrete-time systems." Doctoral thesis, Universitat de Girona, 2007. http://hdl.handle.net/10803/7740.
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La tesis pretende explorar acercamientos computacionalmente confiables y eficientes de contractivo MPC para sistemas de tiempo discreto. Dos tipos de contractivo MPC han sido estudiados: MPC con coacción contractiva obligatoria y MPC con una secuencia contractiva de conjuntos controlables. Las técnicas basadas en optimización convexa y análisis de intervalos son aplicadas para tratar MPC contractivo lineal y no lineal, respectivamente. El análisis de intervalos clásicos es ampliado a zonotopes en la geometría para diseñar un conjunto invariante de control terminal para el modo dual de MPC. También es ampliado a intervalos modales para tener en cuenta la modalidad al calcula de conjuntos controlables robustos con una interpretación semántica clara. Los instrumentos de optimización convexa y análisis de intervalos han sido combinados para mejorar la eficacia de contractive MPC para varias clases de sistemas de tiempo discreto inciertos no lineales limitados. Finalmente, los dos tipos dirigidos de contractivo MPC han sido aplicados para controlar un Torneo de Fútbol de Copa Mundial de Micro Robot (MiroSot) y un Tanque-Reactor de Mezcla Continua (CSTR), respectivamente.The thesis aims to explore computationally reliable and efficient approaches of contractive MPC for discrete-time systems. Two types of contractive MPC have been studied: MPC with compulsory contractive constraint and MPC with a contractive sequence of controllable sets. Techniques based on convex optimization and interval analysis are applied to deal with linear and nonlinear contractive MPC, respectively. Classical interval analysis is extended to zonotopes in geometry for designing a terminal control invariant set in the dual-mode approach of MPC. It is also extended to modal intervals in modality for computing robust controllable sets with a clear semantic interpretation. The tools of convex optimization and interval analysis have been combined further to improve the efficiency of contractive MPC for various kinds of constrained nonlinear uncertain discrete-time systems. Finally, the addressed two types of contractive MPC have been applied to control a Micro Robot World Cup Soccer Tournament (MiroSot) robot and a Continuous Stirred-Tank Reactor (CSTR), respectively.
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Navarro, López Eva Maria. "Dissipativity and passivity-related properties in nonlinear discrete-time systems." Doctoral thesis, Universitat Politècnica de Catalunya, 2002. http://hdl.handle.net/10803/5938.
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El propósito de la presente tesis es el estudio de la disipatividad en sistemas no lineales discretos. Dicho trabajo de investigación presenta nuevas contribuciones en la teoría de control no lineal discreto basado en disipatividad y en el estudio de las propiedades de sistemas disipativos no lineales. Los resultados conseguidos se dividen en tres objetivos principales:1. La caracterización de sistemas disipativos múltiple entrada múltiple salida (MIMO) no lineales discretos de estructura general, lo que también se conoce como condiciones de Kalman-Yakubovich-Popov (KYP). Las condiciones de KYP ya existentes se extienden a una clase de sistemas disipativos discretos no lineales MIMO que son no afines en el control. La clase de sistemas disipativos estudiada se denomina disipatividad QSS. También se proporcionan condiciones necesarias y suficientes para la caracterización de sistemas conservativos QSS discretos no afines en el control.
2. El problema de disipatividad por realimentación en sistemas no lineales discretos. Se proponen dos formas de abordar dicho problema:
2.1. El problema de la disipatividad por realimentación a través de la relación fundamental de la disipatividad. Se da solución al problema de la disipatividad por realimentación para sistemas única entrada única salida (UEUS) discretos no lineales no afines en el control, mediante cuatro metodologías basadas en la igualdad fundamental de la disipatividad. Se proponen condiciones suficientes bajo las cuales la disipatividad por realimentación es posible.
2.2. El problema de pasivización mediante las propiedades del grado relativo y la dinámica cero del sistema no pasivo original. El problema de transformarción de un sistema no pasivo a uno que lo es se resuelve mediante realimentación de estado para una clase de sistemas MIMO no lineales discretos afines en el control, usando las propiedades del grado relativo y la dinámica cero del sistema no pasivo original. Se puede considerar como una extensión al caso pasivo de los resultados ya existentes, referentes al problema de transformar un sistema que no es conservativo a uno que lo es mediante realimentación de estado.
3. El problema de estabilización basado en disipatividad en sistemas no lineales discretos. El método de Moldeo de Energía e Inyección de Amortiguamiento (MEIA) se extiende a sistemas generales no lineales discretos UEUS, además de analizar algunas de las propiedades de estabilidad de una clase de sistemas disipativos y de sistemas que se pueden transformar a disipativos por realimentación. También, se establecen condiciones suficientes bajo las cuales dichos sistemas son estabilizables.
Otros objetivos secundarios han sido alcanzados, como son: el estudio del grado relativo y la dinámica cero de sistemas pasivos no lineales discretos, algunas conclusiones acerca de la conservación de la pasividad bajo la interconexión por retroalimentación negativa y la interconexión paralela, algunas notas acerca de la conservación y pérdida de la disipatividad y pasividad con el muestreo, además, las propiedades en el dominio de la frecuencia de los sistemas disipativos se usan y se relacionan con algunos de los criterios de estabilidad basados en la respuesta en frecuencia más importantes. También, los métodos de control basados en disipatividad diseñados se aplican al problema de regulación de un modelo discreto con interpretación física: un convertidor buck, para el que se mejora la respuesta en lazo abierto.
El hecho de haber tratado sistemas discretos generales nos ha permitido dar una serie de resultados para sistemas no lineales continuos no afines en el control. Dos problemas se han propuesto, principalmente: el estudio de la disipatividad por realimentación para sistemas no lineales no afines UEUS y el uso de los resultados de disipatividad por realimentación, con el fin de extender al caso no lineal no afín UEUS el método de estabilización de MEIA.
This dissertation is devoted to dissipativity-related concepts in the nonlinear discrete-time setting, and presents several new contributions which are not covered by the existing nonlinear discrete-time dissipativity-based control theory and the study of the properties of nonlinear discrete-time dissipative systems.
The study of dissipativity given in this dissertation is concentrated in the state-space or internal description representation of systems. The results achieved are classified into three main goals or problems to solve, such as:
1. The characterization of dissipative multiple-input multiple-output (MIMO) nonlinear discrete-time systems of general form, what is regarded as Kalman-Yakubovich-Popov (KYP) conditions. The KYP conditions existing in the literature are extended to a class of nonlinear MIMO dissipative discrete-time systems which are non-affine in the control input. The class of dissipativity characterized is regarded as QSS-dissipativity. Necessary and sufficient conditions for the characterization of QSS-lossless discrete-time systems which are non-affine in the control input are also given.
2. The feedback dissipativity problem in the nonlinear discrete-time setting. Two approaches are proposed to deal with this topic:
2.1. The feedback dissipativity problem through the fundamental dissipativity inequality. The feedback dissipativity problem is solved for single-input single-output (SISO) nonlinear discrete-time non-affine-in-the-control-input systems by means of four methodologies based on the fundamental dissipativity equality. Sufficient conditions under which feedback dissipativity is possible are proposed.
2.2. The feedback passivity problem through the properties of the relative degree and zero dynamics of the non-passive system. The problem of rendering a system passive via state feedback is solved for a class of MIMO nonlinear discrete-time systems which are affine in the control input using the properties of the relative degree and the zero dynamics of the non-passive system. It is an extension to the passivity case of the results reported in the literature for the losslessness feedback problem.
3. The dissipativity-based stabilization problem in nonlinear discrete-time systems. The dissipativity-based controller design methodology of the Energy Shaping and Damping Injection (ESDI) is extended to general nonlinear SISO discrete-time systems, in addition to, the analysis of some stability properties of a class of dissipative and feedback dissipative SISO nonlinear discrete-time systems. Furthermore, sufficient conditions under which a class of feedback dissipative systems is stabilizable are proposed.
Other secondary goals in the dissipativity properties exploration in discrete-time systems are achieved, mainly: the study of the relative degree and zero dynamics of passive nonlinear discrete-time systems, some conclusions about passivity preservation under feedback and parallel interconnections, some notes on the non-preservation and preservation of dissipativity, and its special case of passivity, under sampling, in addition, dissipativity frequency-domain properties have been used and related to some of the most important frequency-based feedback stability criteria. Furthermore, the feedback dissipativity and dissipativity-based control results are applied to solve the regulation problem in a discrete-time model with physical interpretation: the DC-to-DC buck converter, whose open-loop response is improved by means of the use of some of the stabilization methods proposed.
The fact of treating general discrete-time systems has allowed us to extend some dissipativity-related definitions to the case of continuous-time nonlinear non-affine-in-the-input systems. Two main problems are presented, namely: the study of the feedback dissipativity problem for nonlinear non-affine SISO systems based upon the fundamental dissipativity equality, and the use of the feedback dissipativity results in order to extend the ESDI controller design method to the case of non-affine SISO nonlinear systems.
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Schleyer, Marc. "Discrete time analysis of batch processes in material flow systems." Karlsruhe : Univ.-Verl. Karlsruhe, 2007. http://www.uvka.de/univerlag/volltexte/2007/243/.
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Rakovic, Sasa. "Robust control of constrained discrete time systems : characterization and implementation." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420961.
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Ouaknine, Joel. "Discrete analysis of continuous behaviour in real-time concurrent systems." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365293.
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Vogts, Holger [Verfasser], and St [Akademischer Betreuer] Süllow. "Discrete Time Quantum Lattice Systems / Holger Vogts ; Betreuer: St. Süllow." Braunschweig : Technische Universität Braunschweig, 2009. http://d-nb.info/1175829870/34.
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Govindaswamy, Srinath. "Output sampling based sliding mode control for discrete time systems." Thesis, University of Kent, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.591931.
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This thesis concerns the development of output-based sliding mode control schemes for discrete time, linear time invariant systems. Unlike most of the work given in the literature in this area, the work is concemed with the development of static output feedback based discrete time sliding mode control schemes for non-minimum phase, non-square systems with arbitrary relative degree and which include unmatched uncertainties. The key concept of extended outputs in discrete time will be introduced. It will be shown that by identifying a minimal set of present and past outputs an augmented system can be obtained which permits the design of a sliding manifold based upon output information only, which renders the sliding manifold stable. Any transmission zeros of the augmented plant will also be shown to be among the transmission zeros of the original plant. It will also be shown that if the extended outputs chosen span the state zero directions of an invariant zero of the system, then the invariant zero disappears from the augmented system. Linear matrix inequalities are then used for sliding surface design. For non-minimum phase, non-square systems with unmatched uncertainties, it will be shown that in some cases the extended outputs can be chosen such that the effect of the disturbance on the sliding surface can be nullified. If this is possible, a procedure to obtain a Lyapunov matrix, which simultaneously satisfies a Riccati inequality and a structural constraint and which is used to formulate the control law that satisfies the reachability condition has been given. For the general case, where the sliding surface is a function of the disturbance, a control law will be chosen such that the effect of the disturbance on the augmented outputs and the sliding manifold will be minimized. Another key contribution of this work is the use of extended outputs for reconfigurable control under sensor loss. The reconfigurable control methodology presented in this work is in discrete time and is a static output feedback based control scheme, unlike most of the reconfigurable control schemes given in the literature which require an estimator and which are continuous time based schemes. Suitable examples, which include multiple sensor failures and a benchmark problem taken from the literature which represents the lateral dynamics of the F-14 aircraft, have been chosen to show the effectiveness of the proposed control design methodologies. - L Abstract T his thesis concerns the development of out put-based sliding mode control schemes for discrete time, linear time invariant systems. Unlike most of the work given in the literature in this area, the work is concerned with the development of static output feedback based discrete time sliding mode control schemes for non-minimum phase, non-square systems with arbitrary relative degree and which include unmatched uncertainties. The' key concept of extended outputs in discrete time will be introduced. It will be shown that by identifying a minimal set of present and past outputs an augmented system can be obtained which permits the design of a sliding manifold based upon output information only, which renders the sliding manifold stable. Any transmission zeros of the augmented plant will also be sho,wn to be among the transmission zeros of the original plant. It will also be shown that- if the extended outputs chosen span the state zero directions of an invariant zero of the system, then the invariant zero disappears from the augment.ed system. Linear matrix inequalities are then used for sliding surface design. For nonminimurn phase, non-square systems with unmatched uncertainties, it will be shown that in some cases the extended outputs can be chosen such ,that the effect of the disturbance on the sliding surface can be nullified. If this is possible, a procedure to obtain a Lyapunov matrix, which simultaneously satisfies a Riccati inequality and a structural constraint and which is used to formulate the control law t hat satisfies the reachability condit ion has been given. For the general case, where the sliding surface is a function of the disturbance, a control law will be chosen such that the effect of the disturbance on the augmented outputs and the sliding manifold will be minimized. Another key contribution of t his work is the use of extended outputs for reconfigurable control under sensor loss. The reconfigura~le control methodology presented in this work is in discrete time and is a static output feedback based control scheme, unlike most of t he reconfigurable control schemes given in the literature which require an estimator and which are continuous time based schemes. Suitable examples, which include multiple sensor failures and a benchmark problem taken from the literature which represents the lateral dynamics of the F-14 aircraft have been chosen to show the effectiveness of the proposed control design methodologies.
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Perreira, Das Chagas Thiago. "Stabilization of periodic orbits in discrete and continuous-time systems." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00852424.
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The main problem evaluated in this manuscript is the stabilization of periodic orbits of non-linear dynamical systems by use of feedback control. The goal of the control methods proposed in this work is to achieve a stable periodic oscillation. These control methods are applied to systems that present unstable periodic orbits in the state space, and the latter are the orbits to be stabilized.The methods proposed here are such that the resulting stable oscillation is obtained with low control effort, and the control signal is designed to converge to zero when the trajectory tends to the stabilized orbit. Local stability of the periodic orbits is analyzed by studying the stability of some linear time-periodic systems, using the Floquet stability theory. These linear systems are obtained by linearizing the trajectories in the vicinity of the periodic orbits.The control methods used for stabilization of periodic orbits here are the proportional feedback control, the delayed feedback control and the prediction-based feedback control. These methods are applied to discrete and continuous-time systems with the necessary modifications. The main contributions of the thesis are related to these methods, proposing an alternative control gain design, a new control law and related results.
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Perel, Ron Yitzhak 1975. "Learning control for a class of discrete-time, nonlinear systems." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/46684.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1999.Includes bibliographical references (p. 132-134).
Over the last few decades, control theory has developed to the level where reliable methods exist to achieve satisfactory performance on even the largest and most complex of dynamical systems. The application of these control methods, though, often require extensive modelling and design effort. Recent techniques to alleviate the strain on modellers use various schemes which allow a particular system to learn about itself by measuring and storing a large, arbitrary collection of data in compact structures such as neural networks, and then using the data to augment a controller. Although many such techniques have demonstrated their capabilities in simulation, performance guarantees are rare. This thesis proposes an alternate learning technique, where a controller, based on minimal initial knowledge of system dynamics, acquires a prescribed data set on which a new controller, with guaranteed performance improvements, is based.
by Ron Yitzhak Perel.
S.M.
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Rao, V. A. P. "Markov chain Monte Carlo for continuous-time discrete-state systems." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1349490/.
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A variety of phenomena are best described using dynamical models which operate on a discrete state space and in continuous time. Examples include Markov (and semi-Markov) jump processes, continuous-time Bayesian networks, renewal processes and other point processes. These continuous-time, discrete-state models are ideal building blocks for Bayesian models in fields such as systems biology, genetics, chemistry, computing networks, human-computer interactions etc. However, a challenge towards their more widespread use is the computational burden of posterior inference; this typically involves approximations like time discretization and can be computationally intensive. In this thesis, we describe a new class of Markov chain Monte Carlo methods that allow efficient computation while still being exact. The core idea is an auxiliary variable Gibbs sampler that alternately resamples a random discretization of time given the state-trajectory of the system, and then samples a new trajectory given this discretization. We introduce this idea by relating it to a classical idea called uniformization, and use it to develop algorithms that outperform the state-of-the-art for models based on the Markov jump process. We then extend the scope of these samplers to a wider class of models such as nonstationary renewal processes, and semi-Markov jump processes. By developing a more general framework beyond uniformization, we remedy various limitations of the original algorithms, allowing us to develop MCMC samplers for systems with infinite state spaces, unbounded rates, as well as systems indexed by more general continuous spaces than time.
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Chagas, Thiago Pereira das. "Stabilization of periodic orbits in discrete and continuous-time systems." Instituto Tecnológico de Aeronáutica, 2013. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2770.
Full textAbstract:
The main problem evaluated in this manuscript is the stabilization of periodic orbits of non-linear dynamical systems by use of feedback control. The goal of the control methods proposed in this work is to achieve a stable periodic oscillation. These control methods are applied to systems that present unstable periodic orbits in the state space, and the latter are the orbits to be stabilized. The methods proposed here are such that the resulting stable oscillation is obtained with low control effort, and the control signal is designed to converge to zero when the trajectory tends to the stabilized orbit. Local stability of the periodic orbits is analyzed by studying the stability of some linear time-periodic systems, using the Floquet stability theory. These linear systems are obtained by linearizing the trajectories in the vicinity of the periodic orbits. The control methods used for stabilization of periodic orbits here are the proportional feedback control, the delayed feedback control and the prediction-based feedback control. These methods are applied to discrete and continuous-time systems with the necessary modifications. The main contributions of the thesis are related to these methods, proposing an alternative control gain design, a new control law and related results.
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Takaba, Kiyotsugu. "Studies on H∞ Filtering Problems For Linear Discrete-Time Systems." Kyoto University, 1996. http://hdl.handle.net/2433/77827.
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Barth, Eric J. "Approximating discrete-time optimal control using a neural network." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/19009.
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Yankov, Y. Daniel. "Discrete event system modeling of demand responsive transportation systems operating in real time." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002466.
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Yankov, Daniel Y. "Discrete Event System Modeling Of Demand Responsive Transportation Systems Operating In Real Time." Scholar Commons, 2008. https://scholarcommons.usf.edu/etd/575.
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Demand responsive transportation is a variable route service of passengers or freight from specific origin(s) to destination(s) in response to the request of users. Operational planning of DRT system encompasses the methods to provide efficient service to the passengers and to the system operators. These methods cover the assignments of vehicles to transportation requests and vehicle routings under various constraints such as environmental conditions, traffic and service limitations. Advances in the information and communication technologies, such as the Internet, mobile communication devices, GIS, GPS, Intelligent Transportation Systems have led to a significantly complex and highly dynamical decision making environment. Recent approaches to DRT operational planning are based on "closed information loop" to achieve a higher level of automation, increased flexibility and efficiency.
Intelligent and effective use of the available information in such a complex decision making environment requires the application of formal modeling and control approaches, which are robust, modular and computationally efficient. In this study, DRT systems are modeled as Discrete Event Systems using Finite Automata formalism and DRT real time control is addressed using Supervisory Control Theory. Two application scenarios are considered; the first is based on air-charter service and illustrates uncontrolled system model and operational specification synthesis. The automatic synthesis of centralized and modular supervisors is demonstrated. The second scenario is a mission critical application based on emergency evacuation problem. Decentralized supervisory control architecture suitable for accommodating the real-time contingencies is presented.
Conditions for parallel computation of local supervisors are specified and the computational advantages of alternative supervisory control architectures are discussed. Discrete event system modeling and supervisory control theory are well established and powerful mathematical tools. In this dissertation, they are shown to be suitable for expressing the modeling and control requirements of complex and dynamic applications in DRT. The modeling and control approaches described herein, coupled with the mature body of research literature in Discrete Event Systems and Supervisory Control Theory, facilitate logical analysis of these complex systems and provide the necessary framework for development of intelligent decision making tools for real time operational planning and control in a broad range of DRT applications.
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Jeong, Daehwa. "Analysis and design of a discrete time repetitive control system /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/7079.
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Unwala, Ishaq Hasanali. "Pipelined processor modeling with finite homogeneous discrete-time Markov chain /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Jayaraman, Gangadhar. "Computational schemes for exact linearization of discrete-time systems using a geometric approach." Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1058542922.
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Brat, Guillaume Philippe. "A (max,+) algebra for non-stationary and non-deterministic periodic discrete event systems /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Tsai, Jya-Jang. "Toward automatic parallelization of discrete event simulation programs." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/8302.
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Göeggel, Mathias Christian. "Closed-form solutions to discrete-time portfolio optimization problems." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2010. http://scholarsmine.mst.edu/thesis/pdf/Goeggel_09007dcc807a9b0b.pdf.
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Thesis (M.S.)--Missouri University of Science and Technology, 2010.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed June 7, 2010) Includes bibliographical references (p. 75).
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Lynch, Elizabeth Whitaker. "Hardware acceleration for conservative parallel discrete event simulation on multi-core systems." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39506.
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Multi-core architectures are becoming more common and core counts continue to increase. There are six- and eight-core chips currently in production, such as Intel Gulftown, and many-core chips with dozens of cores, such as the Intel Teraflops 80-core chip, are projected in the next five years. However, adding more cores often does not improve the performance of applications. It would be desirable to take advantage of the multi-core environment to speed up parallel discrete event simulation. The current bottleneck for many parallel simulations is time synchronization. This is especially true for simulations of wireless networks and on-chip networks, which have low lookahead. Message passing is also a common simulation bottleneck. In order to address the issue of time synchronization, we have designed hardware at a functional level that performs the time synchronization for parallel discrete event simulation asynchronously and in just a few clock cycles, eliminating the need for global communication with message passing or lock contention for shared memory. This hardware, the Global Synchronization Unit, consists of 3 register files, each the size of the number of cores, and is accessed using 5 new atomic instructions. In order to reduce the simulation overhead from message passing, we have also designed two independent pieces of hardware at a functional level, the Atomic Shared Heap and Atomic Message Passing, which can be used to perform lock-free, zero-copy message passing on a multi-core system. The impact of these specialized hardware units on the performance of parallel discrete event simulation is assessed and compared to traditional shared-memory techniques.