compressible navier stokes equations with degenerate viscosity coefficient and vacuum in this paper we consider the compressible navier stokes equations for isentropic flow of finite total mass when the initial density is either of compact or infinite support the viscosity coefficient is assumed to be a power function of the density so that the cauchy problem is well posed new global existence results are established when the density function connects to the vacuum states continuously for this some new a priori estimates are obtained to take care of the degeneracy of the viscosity coefficient at vacuum we will also give a non global existence theorem of regular solutions when the initial data are of compact support in eulerian coordinates which implies singularity forms at the interface separating the gas and vacuum

mini max integral sliding mode control for multimodel linear uncertain systems an original linear time varying system with matched and unmatched disturbances and uncertainties is replaced by a finite set of dynamic models such that each one describes a particular uncertain case including exact realizations of possible dynamic equations as well as external unmatched bounded disturbances such a tradeoff between an original uncertain linear time varying dynamic system and a corresponding higher order multimodel system containing only matched uncertainties leads to a linear multi model system with known unmatched bounded disturbances and unknown matched disturbances as well each model from a given finite set is characterized by a quadratic performance index the developed minimax integral sliding mode control strategy gives an optimal minimax linear quadratic lq control with additional integral sliding mode term the design of this controller is reduced to a solution of an equivalent mini max lq problem that corresponds to the weighted performance indices with weights from a finite dimensional simplex the additional integral sliding mode controller part completely dismisses the influence of matched uncertainties from the initial time instant two numerical examples illustrate this study

robust discrete time chattering free sliding mode control a new control algorithm based on discrete time variable structure systems theory is proposed the basic feature of this algorithm is that trajectories reach the sliding manifold in finite time without chattering apart from stability the robustness of the algorithm with respect to parameter uncertainties as well as external disturbances is considered it is demonstrated that the robustness is improved by decreasing the sampling period the theory is illustrated on a dc servo position system

adaptive sliding mode control in discrete time systems abstract discrete time sliding mode control is considered the case of known parameters is first analyzed leading to a new definition of the so called equivalent control as the piecewise constant control that reduces to zero in finite time the distance of the system state from the sliding manifold in the presence of bounded parametric uncertainties an adaptive control scheme that guarantees the asymptotic satisfaction of the same control objective is presented the main feature of this approach is the reduction of the order of the relevant error equation and the possibility of dealing with the nonmatched uncertainties introduced by the sampling process

sliding mode control of a discrete system abstract conventional sliding mode control designed on the basis of a continuous system is known to be robust to the plant uncertainties a realized digital system however not only yields chattering but also may become unstable by a long sampling interval this paper presents a stable discrete sliding mode control insensitive to the choice of sampling interval and not yielding chattering the control system is designed on the basis of a discrete lyapunov function and a sufficient condition of the control gain to make the system stable is given contrary to the continuous case the derived switching plane of the control law is different from the sliding mode and in its neighborhood the control law is given by the linear state feedback simulations show the effectiveness of the proposed method

optimal integral sliding mode control scheme based on pseudospectral method for robotic manipulators for a multi input multi output nonlinear system an optimal integral sliding mode control scheme based on pseudospectral method is proposed in this paper and the controller is applied on rigid robotic manipulators with constraints first a general form of integral sliding mode is designed with the aim of restraining disturbance then pseudospectral method is adopted to deal with constrained optimal control problem in consideration of the benefits of both methods an optimal integral sliding mode controller is given which is based on the combination of integral sliding mode and pseudospectral method the stability analysis shows that the controller can guarantee stability of robotic manipulator system simulations show the effectiveness of proposed method

linear quadratic regulation for linear time varying systems with multiple input delays this paper studies the classic linear quadratic regulation lqr problem for both continuous time and discrete time systems with multiple input delays for discrete time systems the lqr problem for systems with single input delay has been studied in existing literature whereas a solution to the multiple input delay case is not known to our knowledge for continuous time systems with multiple input delays the lqr problem has been tackled via an infinite dimensional system theory approach and a frequency time domain approach the objective of the present paper is to give an explicit solution to the lqr problem via a simple and intuitive approach the main contributions of the paper include a fundamental result of duality between the lqr problem for systems with multiple input delays and a smoothing problem for an associated backward stochastic system the duality allows us to obtain a solution to the lqr problem via standard projection in linear space the lqr controller is simply constructed by the solution of one backward riccati difference for the discrete time case or differential for the continuous time case equation of the same order as the plant ignoring the delays

strong solutions of the navier stokes equations for isentropic compressible fluids we study strong solutions of the isentropic compressible navier stokes equations in a domain r3 we first prove the local existence of unique strong solutions provided that the initial data 0 and u0 satisfy a natural compatibility condition the important point in this paper is that we allow the initial vacuum the initial density may vanish in an open subset of we then prove a new uniqueness result and stability result our results are valid for unbounded domains as well as bounded ones

global solution to the compressible isothermal multipolar fluid abstract the global existence of weak solutions of the initial boundary value problem in bounded domains to the system of partial differential equations for viscous compressible isothermal bipolar and multipolar fluids is proved some other properties as cavitation regularity up to the strong solution and uniqueness are discussed

generalization of gao s reaching law for higher relative degree sliding variables in this paper a generalized discrete time reaching law for sliding variables with arbitrary relative degree is proposed the reaching law is based on gao s strategy and ensures higher order switching type sliding motion which is a novel concept in the field of discrete time plants the controller synthesis process is simplified by performing a specific system state transformation it is demonstrated that the width of the layer to which the representative point of the system is driven decreases as the relative degree of the sliding variable gets bigger it has further been proven that achieving a narrower quasi sliding mode band width is reflected in reduced state error finally the reaching phase elimination for variables with arbitrary relative degree is considered this is obtained by implementing a time varying sliding surface in a finite number of initial time instants uniform ultimate boundedness of all state variables is guaranteed

robust h sub spl infin control for uncertain discrete time delay fuzzy systems via output feedback controllers this work investigates the problem of robust output feedback h sub spl infin control for a class of uncertain discrete time fuzzy systems with time delays the state space takagi sugeno fuzzy model with time delays and norm bounded parameter uncertainties is adopted the purpose is the design of a full order fuzzy dynamic output feedback controller which ensures the robust asymptotic stability of the closed loop system and guarantees an h sub spl infin norm bound constraint on disturbance attenuation for all admissible uncertainties in terms of linear matrix inequalities lmis a sufficient condition for the solvability of this problem is presented explicit expressions of a desired output feedback controller are proposed when the given lmis are feasible the effectiveness and the applicability of the proposed design approach are demonstrated by applying this to the problem of robust h sub spl infin control for a class of uncertain nonlinear discrete delay systems

on the strong solutions of one dimensional navier stokes poisson equations for compressible non newtonian fluids we study the strong solutions of 1d navier stokes poisson equations for compressible non newtonian fluids in bounded intervals the model is raised from the viscous isentropic gas flow under considering an external force and the non newtonian gravitational force term by using the iterative method we prove the local existence and uniqueness of strong solutions based on some compatibility condition the main condition is that the initial density vacuum is allowed

clairvoyant and adaptive signal detection in non gaussian clutter a data dependent threshold interpretation this paper addresses the problem of signal detection in correlated non gaussian clutter modeled as a spherically invariant random process the optimum strategy to detect a constant signal with either known or unknown complex amplitude embedded in correlated gaussian clutter is given by comparing the whitening matched filter output with a fixed threshold when the clutter is non gaussian the performance of the matched filter sensibly degrades the optimum strategy is the classical whitening matched filter output compared with a data dependent threshold this interpretation provides a deeper insight into the structure of the optimum detector and allows us to single out a family of suboptimum detectors based on a polynomial approximation of the data dependent threshold they are easy to implement and have performance that is really close to the optimal the adaptive implementation of the polynomial detectors is also investigated and their performance is analyzed by means of monte carlo simulation for various clutter scenarios

congestion control as a stochastic control problem with action delays we consider the design of explicit rate based congestion control for high speed communication networks and show that this can be formulated as a stochastic control problem where the controls of different users enter the system dynamics with different delays we discuss the existence derivation and the structure of the optimal controller as well as of suboptimal controllers of the certainty equivalent type a terminology that is precisely defined in the paper for the specific context of the congestion control problem considered we consider in particular two certainty equivalent controllers which are easy to implement and show that they are stabilizing i e they lead to bounded infinite horizon average cost and stable queue dynamics further these controllers perform well in simulations

state feedback control of continuous time t s fuzzy systems via switched fuzzy controllers this paper studies the problem of state feedback control of continuous time t s fuzzy systems switched fuzzy controllers are exploited in the control design which are switched based on the values of membership functions and the control scheme is an extension of the parallel distributed compensation pdc scheme sufficient conditions for designing switched state feedback controllers are obtained with meeting an h norm bound requirement and quadratic d stability constraints it is shown that the new control design method provides less conservative results than the corresponding ones via the parallel distributed compensation pdc scheme a numerical example is given to illustrate the effectiveness of the proposed method

non linear discrete variable structure systems in quasi sliding mode abstract the problem of inducing convergent quasi sliding regimes on smooth state space surfaces of non linear single input single output discrete time controlled systems is addressed in full generality a suitable extension of the notion of relative degree is used in establishing the most salient features of quasi sliding motions in non linearly controlled systems several examples are given

static output feedback controller design for fuzzy systems an ilmi approach this paper examines the problem of static output feedback control of a takagi sugeno ts fuzzy system the existence of a static output feedback control law is given in terms of the solvability of bilinear matrix inequalities an iterative algorithm based on the linear matrix inequality is proposed to compute the static output feedback gain to reduce the conservatism of the design the structural information of the membership function of the fuzzy rules is incorporated numerical examples are used to illustrate the validity of the methods

existence and uniqueness of solutions for a class of non newtonian fluids with vacuum and damping abstract in this paper we proved local existence and uniqueness of solutions for a class of non newtonian fluids with vacuum and damping in one dimensional bounded intervals the main difficulty is due to the strong nonlinearity of the system and initial vacuum

robust h sub spl infin control for fuzzy systems with frobenius norm bounded uncertainties in this paper we investigate the problem of robust h sub spl infin performance and stabilization for a class of uncertain fuzzy systems with frobenius norm bounded parameter uncertainties in all system matrices both continuous and discrete time uncertain fuzzy systems are considered under a unified treatment called bounded real lemma for fuzzy systems unlike the bounded real lemma in the linear theory of robust h sub spl infin control where necessary and sufficient conditions were obtained only sufficient condition based on lyapunov method is shown furthermore connection between robust h sub spl infin problems involving uncertainty and standard uncertainty free h sub spl infin problems is established via matrix algebra as for controller synthesis a state feedback fuzzy control law is designed via relaxed linear matrix inequality lmi formulations

bootstrap based detection of signals with unknown parameters in unspecified correlated interference a detection scheme that uses estimators for signal frequency amplitude and phase to detect signals in correlated interference is proposed the scheme does not require training data but uses the bootstrap to estimate the distribution of the test statistic under the null hypothesis directly from the received data simulation results are provided that confirm the detector performance for correlated gaussian and non gaussian interference and the consistency of the estimators the detector asymptotically maintains the preset level of false alarm and a detection rate of 100 is achievable at 5 db signal to noise ratio snr for sample sizes as small as 500 data points the case where the arrival time of the signal is unknown is also treated simulation results showing the performance of the detector when it is suitably extended to handle this case are given

brief paper zoh discretization effect on single input sliding mode control systems with matched uncertainties in this paper discretization behaviors of equivalent control based sliding mode control systems with matched uncertainties are studied upper bounds for system steady states are established some inherent dynamical periodic properties of the systems subject to matched constant and periodic uncertainties are explored simulations are presented to verify the theoretical results

h sub spl infin output feedback control of discrete time fuzzy systems with application to chaos control this paper presents an observer based h sub spl infin output feedback synthesis method for discrete time fuzzy dynamic systems based on a piecewise lyapunov function the basic idea of the approach is to design an observer based piecewise linear output feedback control law to guarantee the global stability with h sub spl infin performance of the resulting closed loop fuzzy control systems it is shown that the controller parameters can be obtained by solving a set of linear matrix inequalities lmis that are numerically feasible with commercially available software application to control chaotic systems is given to illustrate the effectiveness and advantages of the proposed method

on the discrete time integral sliding mode control a new discrete time integral sliding mode control dismc scheme is proposed for sampled data systems the new control scheme is characterized by a discrete time integral sliding manifold which inherits the desired properties of the continuous time integral sliding manifold such as full order sliding manifold with pole assignment and elimination of the reaching phase in particular comparing with existing discrete time sliding mode control the new scheme is able to achieve more precise tracking performance it will be shown in this work that the new control scheme achieves o t2 steady state error for state regulation with the widely adopted delay based disturbance estimation another desirable feature is the proposed dismc prevents the generation of overlarge control actions due to deadbeat response which is usually inevitable due to the existence of poles at the origin for a reduced order sliding manifold designed for sampled data systems both the theoretical analysis and illustrative example demonstrate the validity of the proposed scheme

the cfar adaptive subspace detector is a scale invariant glrt the constant false alarm rate cfar matched subspace detector cfar msd is the uniformly most powerful invariant test and the generalized likelihood ratio test glrt for detecting a target signal in noise whose covariance structure is known but whose level is unknown previously the cfar adaptive subspace detector cfar asd or adaptive coherence estimator ace was proposed for detecting a target signal in noise whose covariance structure and level are both unknown and whose covariance structure is estimated with a sample covariance matrix based on training data we show here that the cfar asd is glrt when the test measurement is not constrained to have the same noise level as the training data as a consequence this glrt is invariant to a more general scaling condition on the test and training data than the well known glrt of kelly 1986

existence and uniqueness of solutions for a class of non newtonian fluids with singularity and vacuum abstract the aims of this paper are to discuss existence and uniqueness of local solutions for a class of non newtonian fluids with singularity and vacuum in one dimensional bounded intervals there are two important points in this paper one is that we allow the initial vacuum another one is that the viscosity term of momentum equation is with singularity and fully nonlinearity

technical communique further studies on lmi based relaxed stabilization conditions for nonlinear systems in takagi sugeno s form this paper further studies stabilization of nonlinear systems represented by a takagi sugeno t s discrete fuzzy model by extending a nonquadratic lyapunov function and applying a nonparallel distributed compensation non pdc law a new stabilization conclusion is presented that is a generalization of some previous results in the literature the new conclusion under a special situation is also suitable for a pdc law which presents to be more relaxed than some existing results an example is provided to demonstrate the effectiveness of the new conclusions

fuzzy regulators and fuzzy observers relaxed stability conditions and lmi based designs this paper presents new relaxed stability conditions and lmi linear matrix inequality based designs for both continuous and discrete fuzzy control systems they are applied to design problems of fuzzy regulators and fuzzy observers first takagi and sugeno s fuzzy models and some stability results are recalled to design fuzzy regulators and fuzzy observers nonlinear systems are represented by takagi sugeno s ts fuzzy models the concept of parallel distributed compensation is employed to design fuzzy regulators and fuzzy observers from the ts fuzzy models new stability conditions are obtained by relaxing the stability conditions derived in previous papers lmi based design procedures for fuzzy regulators and fuzzy observers are constructed using the parallel distributed compensation and the relaxed stability conditions other lmi s with respect to decay rate and constraints on control input and output are also derived and utilized in the design procedures design examples for nonlinear systems demonstrate the utility of the relaxed stability conditions and the lmi based design procedures

reaching law for dsmc systems with relative degree 2 switching variable abstractthis paper presents the first attempt to design a reaching law based discrete time sliding mode controller with a relative degree 2 switching variable the current value of this variable is only affected by the control signal and disturbance generated two time instants ago it is demonstrated that the new reaching law based strategy offers a smaller quasi sliding mode band width when compared to a similar control scheme with relative degree 1 switching variable this in turn leads to reduced system output error in the control system proposed in the paper

existence regularity and decay rate of solutions of non newtonian flow the existence and the regularity of young measure valued solutions to non newtonian flows are considered furthermore the uniqueness of solutions and their asymptotic behavior are given

approaches to quadratic stability conditions and h sub spl infin control designs for t s fuzzy systems in this paper the problems of quadratic stability conditions and h sub spl infin control designs for takagi sugeno t s fuzzy systems have been studied first a new quadratic stability condition which is more simple than that in a previous paper has been proposed second two new sufficient conditions in the terms of linear matrix inequalities lmis which guarantee the existence of the state feedback h sub spl infin control for the t s fuzzy systems have been proposed the conditions are not only simple but also consider the interactions among the fuzzy subsystems finally based on the lmis the h sub spl infin controller designing methods for the t s fuzzy systems have been given

robust load frequency control for uncertain nonlinear power systems a fuzzy logic approach a new robust load frequency control lfc methodology is proposed for controlling uncertain nonlinear power systems critical nonlinearity in the power system the valve position limit on the governor and the parametric uncertainty are concerned the takagi sugeno fuzzy model of the power system under consideration is first constructed to design the robust fuzzy model based lfc sufficient conditions for the robust asymptotic convergence of the frequency deviation are then provided in terms of linear matrix inequalities boundedness of the other system variables is also studied to ensure justifiable grounds for use of the proposed lfc method simulation results convincingly validate the effectiveness of the novel lfc design scheme and the theoretical discussions which give a positive answer to the quality control of the electric energy

lq control for ito type stochastic systems with input delays this paper considers the linear quadratic lq control problem for the ito type stochastic system with input delays due to simultaneous appearances of diffusion terms dependent on the state and the control as well as delays in the dynamic system the problem is very involved and remains to be solved we not only provide the solvable condition of the problem but also the explicit expression of the causal and adapted controller for a kind of lq problems all of these are based on a stochastic riccati equation the key technique is to pursue the explicit cost value of the lq problem by fbsde and derive the analytical controller via the interplay between the original problem and its equivalent abstract description

stability analysis and design of takagi sugeno fuzzy systems this work presents stable composite control criteria for multivariable takagi sugeno t s fuzzy systems on the basis of the linear matrix inequality lmi control strategy and parametric optimization the composite fuzzy control algorithms are derived unlike earlier studies of fuzzy control systems on an lmi framework this investigation develops a supervisory control approach such that a fuzzy controller can be synthesized more efficiently moreover a robust control scheme is applied to the t s fuzzy model with parametric uncertainties the sufficient conditions are deduced in the form of reduced lmis and adaptive tuning rules finally numeric simulations are given to validate the proposed approach

local existence of strong solution for a class of compressible non newtonian fluids with non newtonian potential the aim of this paper is to discuss the existence and uniqueness of local solutions for a class of isentropic compressible non newtonian fluids with non newtonian potential in one dimensional bounded intervals the first difficult point in this paper is that we allow the initial vacuum another one is that the viscosity term and newtonian potential term are fully nonlinear that is the viscosity term adopts the o a ladyzhenskaya model p 2 the potential term employs the q laplace form 1

solutions to a class of linear quadratic gaussian lqg stochastic team problems with nonclassical information abstract we consider a stochastic dynamic team problem with two controllers and nonclassical information which can be viewed as the transmission of a garbled version of a gaussian message over a number of noisy channels under a fidelity criterion we show that the optimum solution under a quadratic loss functional consists of linearly transforming the garbled message to a certain optimum power level p and then optimally decoding it by using a linear transformation at the receiving end the power level p is determined by the solution of a fifth order algebraic equation the paper also discusses an extension of this result to the case when the channel noise is correlated with the input random variable and shows that for the single channel case the optimum solution is again linear

h sub spl infin design with pole placement constraints an lmi approach this paper addresses the design of state or output feedback h sub spl infin controllers that satisfy additional constraints on the closed loop pole location sufficient conditions for feasibility are derived for a general class of convex regions of the complex plane these conditions are expressed in terms of linear matrix inequalities lmis and the authors formulation is therefore numerically tractable via lmi optimization in the state feedback case mixed h sub 2 h sub spl infin synthesis with regional pole placement is also discussed finally the validity and applicability of this approach are illustrated by a benchmark example

analysis and design of integral sliding manifolds for systems with unmatched perturbations the robustness properties of integral sliding mode controllers are studied this note shows how to select the projection matrix in such a way that the euclidean norm of the resulting perturbation is minimal it is also shown that when the minimum is attained the resulting perturbation is not amplified this selection is particularly useful if integral sliding mode control is to be combined with other methods to further robustify against unmatched perturbations h sub spl infin is taken as a special case simulations support the general analysis and show the effectiveness of this particular combination

matched subspace detectors we formulate a general class of problems for detecting subspace signals in subspace interference and broadband noise we derive the generalized likelihood ratio glr for each problem in the class we then establish the invariances for the glr and argue that these are the natural invariances for the problem in each case the glr is a maximal invariant statistic and the distribution of the maximal invariant statistic is monotone this means that the glr test glrt is the uniformly most powerful invariant detector we illustrate the utility of this finding by solving a number of problems for detecting subspace signals in subspace interference and broadband noise in each case we give the distribution for the detector and compute performance curves

analytical solutions to a class of non newtonian fluids with free boundaries we study analytical solutions to a class of non newtonian fluids with free boundaries for suitable non newtonian fluids we construct a class of analytical solutions in r with both continuous density condition and the stress free condition across the free boundaries separating the fluid from vacuum such solutions exhibit interesting new information such as the formation of vacuum as time tends to infinitely and explicit regularities and large time decay estimates of the velocity field

relaxed stability and stabilization conditions for a t s fuzzy discrete system it is known that the stability condition of a t s fuzzy discrete system depends on the existence of the common matrix p which satisfies all lyapunov inequalities in general the common matrix p can be found by means of linear matrix inequalities lmi method however if the number of rules of a fuzzy system is large the common matrix p may not exist or may not be found even using lmi therefore in this paper the state space is divided into several subregions and the local common matrix p j for each subregion j is found then the number of lyapunov inequalities to be satisfied by the corresponding local common matrix p j becomes much fewer such that the stability condition of the fuzzy system is more relaxed the similar derivation is also extended to solve the stabilization problem of the t s fuzzy discrete system with parallel distributed compensation

h2 guaranteed cost fuzzy control design for discrete time nonlinear systems with parameter uncertainty this paper presents a design method of h 2 guaranteed cost gc fuzzy controllers for discrete time nonlinear systems with parameter uncertainties the takagi and sugeno t s fuzzy model with parameter uncertainties is employed to represent an uncertain discrete time nonlinear system a sufficient condition for the existence of h 2 gc fuzzy controllers is presented in terms of linear matrix inequalities lmis the resulting fuzzy controllers not only guarantee that the closed loop fuzzy system is quadratically stable but also provide a guaranteed cost on the h 2 performance index furthermore an optimal h 2 gc fuzzy controller in the sense of minimizing a bound on the guaranteed cost is provided by means of an lmi optimization procedure finally it is also demonstrated through numerical simulations on the backing up control of a truck trailer that the proposed design method is effective

blowup of smooth solutions to the compressible navier stokes equation with compact density we present a sufficient condition on the blowup of smooth solutions to the compressible navier stokes equations in arbitrary space dimensions with initial density of compact support as an immediate application it is shown that any smooth solutions to the compressible navier stokes equations for polytropic fluids in the absence of heat conduction will blow up in finite time as long as the initial densities have compact support and an upper bound which depends only on the initial data on the blowup time follows from our elementary analysis immediately another implication is that there is no global small decay in time or even bounded in the case that all the viscosity coefficients are positive smooth solutions to the compressible navier stokes equations for polytropic fluids no matter how small the initial data are as long as the initial density is of compact support this is in contrast to the classical theory of global existence of small solutions to the same system with initial data being a small perturbation of a constant state that is not a vacuum the blowup of smooth solutions to the compressible euler system with initial density and velocity of compact support is a simple consequence of our argument 1998 john wiley sons inc

a strong solution for a class of compressible full non newtonian models abstract the aim of this paper is to discuss the existence and uniqueness of a local solution for a class of isentropic compressible full non newtonian models in one dimensional bounded intervals the first important point in this paper is that we allow the initial vacuum another one is that the viscosity term and the newtonian potential term are fully nonlinear

lyapunov stability and performance analysis of the implicit discrete sliding mode control discrete time sliding mode controllers with an implicit discretization of the signum function are considered with a proper choice of the equivalent part of the control the resulting controller is shown to be lyapunov stable with finite time convergence of the sliding variable to 0 the convergence of the control input as the sampling period goes to 0 to the continuous time one is shown the robustness with respect to matching perturbations is also investigated the discretization performance in terms of the error order is studied for different discretizations of the equivalent part of the input numerical and experimental results illustrate and support the analysis

bipolar isothermal non newtonian compressible fluids the existence and uniqueness of a solution to isothermal non newtonian bipolar fluid is proved we consider a special case where the stress tensor is expressed in the form of potentials depending oneijand eij xk the second part is devoted to the problem of the stability of the rest state it is proved that the perturbations of velocity and density tend to zero in appropriate norms along a chosen time sequence moreover we obtain the asymptotic stability of the rest state under the assumption of the regularity of the potential forces

h_ infty control of discrete time systems with multiple input delays this paper is concerned with the finite horizon hinfin full information control for discrete time systems with multiple control and exogenous input delays we first establish a duality between the hinfin full information control and the h2 smoothing of a stochastic backward system in krein space like the duality between the linear quadratic regulation lqr of linear systems without delays and the kalman filtering the established duality allows us to address complicated multiple input delay problems in a simple way indeed by applying innovation analysis and standard projection in krein space in this paper we derive conditions under which the hinfin full information control is solvable an explicit controller is constructed in terms of two standard riccati difference equations of the same order as the original plant ignoring the delays as special cases solutions to the hinfin state feedback control problem for systems with delays only in control inputs and the hinfin control with preview are obtained an example is given to demonstrate the effectiveness of the proposed hinfin control design

global strong solutions of a class of non newtonian fluids with small initial energy abstract in this paper we are concerned with an initial boundary value problem for a class of non newtonian fluids the viscosity term of momentum equation possesses singularity and nonlinearity and the initial vacuum is allowed the main feature which distinguishes this paper from other related works lies in the fact that we study the global strong solution of the compressible non newtonian fluids with singularity and vacuum in one dimensional bounded intervals and show that there exists a unique global in time strong solution to the problem while the initial energy is small

integral sliding mode controller design for congestion problem in atm networks a new integral sliding mode control strategy for high speed networks operating in asynchronous transfer mode atm is derived to cope with the congestion problem in network flow control the novelty of the proposed design solution stem from allowing high speed networks to have simultaneously acting multiple time varying input delays uncertainties and time varying perturbations a delay dependent condition is derived via the linear matrix inequality approach that guarantees both the asymptotic stability and a prescribed h performance level of the closed loop system in sliding mode dynamics when perturbations of available bit rate bandwidth occur these new results are obtained with no restriction on the derivative of the time varying delays hence are less conservative than the existing ones this control scheme does achieve both of the main goals in atm network traffic namely convergence of the queue length to the desired steady state status and the weighted fairness condition the application to bench

global classical solution to a one dimensional compressible non newtonian fluid with large initial data and vacuum abstract because of the stronger nonlinearity and degeneracies of the density due to the momentum equation and appearance of vacuum there are few results until now about global existence of classical solution to a compressible non newtonian fluid in this paper the global in time existence and uniqueness of classical solution to the initial boundary value problem is established for a one dimensional compressible non newtonian fluid with large initial data and vacuum our analysis is based on some delicate energy estimates together with the iterate method being used ingeniously

asymptotic solutions to weakly coupled stochastic teams with nonclassical information the authors develop a new iterative approach toward the solution of a class of two agent dynamic stochastic teams with nonclassical information when the coupling between the agents is weak either through the state dynamics or through the information channel in each case the weak coupling is characterized in terms of a small perturbation parameter when this parameter value say in is set equal to zero the original fairly complex dynamic team with a nonclassical information pattern is decomposed into or converted to relatively simple stochastic control or team problems the solution of which makes up the zeroth order approximation in a function space to the team optical solution of the original problem the fact that the zeroth order solution approximates the optimal cost up to at least o in is shown it is also shown that approximations of all orders can be obtained by solving a sequence of stochastic control and or simpler team problems

lmi based relaxed nonquadratic stabilization conditions for nonlinear systems in the takagi sugeno s form this paper presents the stabilization analysis for a class of nonlinear systems that are represented by a takagi and sugeno ts discrete fuzzy model takagi and sugeno ieee trans systems man cybern 15 1 1985 116 the main result given here concerns their stabilization using new control laws and new nonquadratic lyapunov functions new relaxed conditions and linear matrix inequality based design are proposed that allow outperforming previous results found in the literature two examples are also provided to demonstrate the efficiency of the approaches

an observer based approach to controlling time delay chaotic systems via takagi sugeno fuzzy model this study presents a fuzzy model based control criterion for time delay chaotic systems with uncertainty the takagi sugeno t s fuzzy model is adopted for representing a chaotic system possessing a time delay a unified approach for designing a fuzzy observer which integrates parallel distributed compensation with an adaptive updating method is first discussed an observer based fuzzy control scheme is then developed to deal with stabilization and tracking problems based on lyapunov stability analysis sufficient conditions that ensure robust control performance of time delay chaotic systems are derived these conditions are represented in terms of linear matrix inequalities and adaptive updating laws finally the proposed approach is validated through numerical synchronization stabilization and model tracking control simulations

rate based flow controllers for communication networks in the presence of uncertain time varying multiple time delays an h based robust controller is designed for a rate feedback flow control problem in single bottleneck communication networks the controller guarantees stability robustness to uncertain time varying multiple time delays in different channels it also brings the queue length at the bottleneck node to the desired steady state value asymptotically and satisfies a weighted fairness condition lower bounds for stability margins for uncertainty in the time delays and for the rate of change of the time delays are derived a number of simulations are included to demonstrate the time domain performance of the controller trade offs between robustness and time domain performance are also discussed