共查询到20条相似文献,搜索用时 31 毫秒
1.
The performance of a network subject to either state dependent or state independent flow control is investigated. In the state dependent case, the flow control policy is a function of the total number of packets for which the controller has not yet received an acknowledgment. In this case it is shown that the optimal flow control is a sliding window mechanism. The effect of the delayed feedback on the network performance as well as the size of the window are studied. The state independent optimal rate is also derived. The performance of the state dependent and state independent flow control policies are compared. Conditions for employing one of the two types of flow control policies for superior end-to-end network performance are discussed. All the results obtained are demonstrated using simple examples. 相似文献
2.
M. Pachter 《Journal of Optimization Theory and Applications》2009,140(2):301-314
The classical finite-dimensional linear-quadratic optimal control problem is revisited. A new linear-quadratic control problem
with linear state penalty terms but without quadratic state penalty terms, is introduced. An optimal control exists and the
closed-form optimal solution is given. It is remarkable that feedback action plays no role and state information does not
feature in the optimal control. The optimal cost function, rather than being quadratic, is linear in the initial state. 相似文献
3.
《Optimization》2012,61(2-3):231-247
In this paper, the Method of Orienting Curves for solving optimal control problems with state constraints, which was introduced by H. X. Phu in 1987, will be extended for a class of regular optimal control problems with one state and one control variable (with state constraints), where the state equation is linear in the control variable 相似文献
4.
Optimal control problem for the exploitation of oil is investigated. The optimal control problem under consideration in this paper is governed by weak coupled parabolic PDEs and involves with pointwise state and control constraints. The properties of solution of the state equations and the continuous dependence of state functions on control functions are investigated in a suitable function space; existence of optimal solution of the optimal control problem is also proved. 相似文献
5.
Peng Shi Eitan Altman Vladimir Gaitsgory 《Mathematical Methods of Operations Research》1998,47(2):289-315
We consider the problem of control for continuous time stochastic hybrid systems in finite time horizon. The systems considered are nonlinear: the state evolution is a nonlinear function of both the control and the state. The control parameters change at discrete times according to an underlying controlled Markov chain which has finite state and action spaces. The objective is to design a controller which would minimize an expected nonlinear cost of the state trajectory. We show using an averaging procedure, that the above minimization problem can be approximated by the solution of some deterministic optimal control problem. This paper generalizes our previous results obtained for systems whose state evolution is linear in the control.This work is supported by the Australian Research Council. All correspondence should be directed to the first author. 相似文献
6.
We study the superconvergence property of fully discrete finite element approximation for quadratic optimal control problems governed by semilinear parabolic equations with control constraints. The time discretization is based on difference methods, whereas the space discretization is done using finite element methods. The state and the adjoint state are approximated by piecewise linear functions and the control is approximated by piecewise constant functions. First, we define a fully discrete finite element approximation scheme for the semilinear parabolic control problem. Second, we derive the superconvergence properties for the control, the state and the adjoint state. Finally, we do some numerical experiments for illustrating our theoretical results. 相似文献
7.
We consider the problem of synthesizing state feedback control policies for condition/event (C/E) systems where the control signals can be both conditions, which enable and inhibit state transitions, and events, which force state transitions. To represent the causal structure of condition and event feedback, a new feedback composition is defined. An algorithm is presented for synthesizing state feedback policies that keep the state of the C/E system out of a given set of forbidden states. The problem formulation and solution is illustrated for a process control example. 相似文献
8.
简述了无应力状态控制法的基本理论,并且介绍了CR列式的基本原理.基于CR列式分析方法,分析了传统增量法和无应力状态控制法参考标架的不同,并在此基础上推导了无应力状态控制法的基本方程,得到的公式表明:采用CR列式分析方法来剖析无应力状态控制法的基本方程,是完全可行的,并且力学概念清晰.最后以实例分析了无应力状态控制法的运用. 相似文献
9.
In this paper finite element approximation of space fractional optimal
control problem with integral state constraint is investigated. First order optimal
condition and regularity of the control problem are discussed. A priori error estimates for control, state, adjoint state and lagrange multiplier are derived. The
nonlocal property of the fractional derivative results in a dense coefficient matrix of
the discrete state and adjoint state equation. To reduce the computational cost a fast
projection gradient algorithm is developed based on the Toeplitz structure of the coefficient matrix. Numerical experiments are carried out to illustrate the theoretical
findings. 相似文献
10.
H. X. Phu 《Journal of Optimization Theory and Applications》1989,62(3):489-513
A method of region analysis is developed for solving a class of optimal control problems with one state and one control variable, including state and control constraints. The performance index is strictly convex with respect to the control variable, while this variable appears only linearly in the state equation. The convexity or linearity assumption of the performance index or the state equation with respect to the state variable is not required.The author would like to express his sincere gratitude to Prof. R. Klötzler, Prof. E. Zeidler, Prof. H. Schumann, Prof. J. Focke, and other colleagues of the Department of Mathematics, Karl Marx University, Leipzig, GDR, for their support during his stay in Leipzig. 相似文献
11.
The numerical approximation to a parabolic control problem with control and state constraints is studied in this paper. We use standard piecewise linear and continuous finite elements for the space discretization of the state, while the dG(0) method is used for time discretization. A priori error estimates for control and state are obtained by an improved maximum error estimate for the corresponding discretized state equation. Numerical experiments are provided which support our theoretical results. 相似文献
12.
Yousong Luo 《Applied Mathematics and Optimization》2010,61(3):337-351
In this paper we derive a necessary optimality condition for a local optimal solution of some control problems. These optimal
control problems are governed by a semi-linear Vettsel boundary value problem of a linear elliptic equation. The control is
applied to the state equation via the boundary and a functional of the control together with the solution of the state equation
under such a control will be minimized. A constraint on the solution of the state equation is also considered. 相似文献
13.
A method for finding the optimal control of linear singular systems with a quadratic cost functional using piecewise linear polynomial functions is discussed. The state variable, state rate, and the control vector are expanded in piecewise linear polynomial functions with unknown coefficients. The relation between the coefficients of the state rate with state variable is provided and the necessary condition of optimality is derived as a linear system of algebraic equations in terms of the unknown coefficients of the state and control vectors. A numerical example is included to demonstrate the validity and the applicability of the technique. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
14.
Numerical analysis for the approximation of optimal control problems with pointwise observations
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Lili Chang Wei Gong Ningning Yan 《Mathematical Methods in the Applied Sciences》2015,38(18):4502-4520
In this paper, we study the numerical methods for optimal control problems governed by elliptic PDEs with pointwise observations of the state. The first order optimality conditions as well as regularities of the solutions are derived. The optimal control and adjoint state have low regularities due to the pointwise observations. For the finite dimensional approximation, we use the standard conforming piecewise linear finite elements to approximate the state and adjoint state variables, whereas variational discretization is applied to the discretization of the control. A priori and a posteriori error estimates for the optimal control, the state and adjoint state are obtained. Numerical experiments are also provided to confirm our theoretical results. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
15.
16.
The problem of optimal control of nonlinear control and state constrained control problems, where the state constraint may involve differential operators and the cost functionals may be nonsmooth, is studied. For this class of problems, necessary optimality conditions using techniques from infinite dimensional optimization theory adapted to the framework of control problems are derived. It is shown that the underlying structure admits a considerable relaxation of the classical constraint qualifications. The theory then is applied to examples of various nonlinear elliptic equations and state constraints. 相似文献
17.
We study the approximation of control problems governed by elliptic partial differential equations with pointwise state constraints. For a finite dimensional approximation of the control set and for suitable perturbations of the state constraints, we prove that the corresponding sequence of discrete control problems converges to a relaxed problem. A similar analysis is carried out for problems in which the state equation is discretized by a finite element method. 相似文献
18.
In this paper, a chemostat model with variable yield and impulsive state feedback control is considered. We obtain sufficient conditions of the globally asymptotical stability of the system without impulsive state feedback control. We also obtain that the system with impulsive state feedback control has periodic solution of order one. Sufficient conditions for existence and stability of periodic solution of order one are given. In some cases, it is possible that the system exists periodic solution of order two. Our results show that the control measure is effective and reliable. 相似文献
19.
In this paper, an optimal control problem for the stationary Navier-Stokes equations in the presence of state constraints is investigated. Existence of optimal solutions is proved and first order necessary conditions are derived. The regularity of the adjoint state and the state constraint multiplier is also studied. Lipschitz stability of the optimal control, state and adjoint variables with respect to perturbations is proved and a second order sufficient optimality condition for the case of pointwise state constraints is stated. 相似文献