scholarly journals The Expected Total Cost Criterion for Markov Decision Processes under Constraints

2013 ◽  
Vol 45 (3) ◽  
pp. 837-859 ◽  
Author(s):  
François Dufour ◽  
A. B. Piunovskiy
Keyword(s):  
Markov Decision Processes ◽  
Optimal Solution ◽  
Decision Processes ◽  
Linear Program ◽  
Programming Approach ◽  
Stationary Policy ◽  
Total Cost ◽  
Optimal Value ◽  
Markov Decision ◽  
Expected Total Cost

In this work, we study discrete-time Markov decision processes (MDPs) with constraints when all the objectives have the same form of expected total cost over the infinite time horizon. Our objective is to analyze this problem by using the linear programming approach. Under some technical hypotheses, it is shown that if there exists an optimal solution for the associated linear program then there exists a randomized stationary policy which is optimal for the MDP, and that the optimal value of the linear program coincides with the optimal value of the constrained control problem. A second important result states that the set of randomized stationary policies provides a sufficient set for solving this MDP. It is important to note that, in contrast with the classical results of the literature, we do not assume the MDP to be transient or absorbing. More importantly, we do not impose the cost functions to be nonnegative or to be bounded below. Several examples are presented to illustrate our results.

scholarly journals The Expected Total Cost Criterion for Markov Decision Processes under Constraints

2013 ◽  
Vol 45 (03) ◽  
pp. 837-859 ◽  
Author(s):  
François Dufour ◽  
A. B. Piunovskiy
Keyword(s):  
Markov Decision Processes ◽  
Optimal Solution ◽  
Decision Processes ◽  
Linear Program ◽  
Programming Approach ◽  
Stationary Policy ◽  
Total Cost ◽  
Optimal Value ◽  
Markov Decision ◽  
Expected Total Cost

In this work, we study discrete-time Markov decision processes (MDPs) with constraints when all the objectives have the same form of expected total cost over the infinite time horizon. Our objective is to analyze this problem by using the linear programming approach. Under some technical hypotheses, it is shown that if there exists an optimal solution for the associated linear program then there exists a randomized stationary policy which is optimal for the MDP, and that the optimal value of the linear program coincides with the optimal value of the constrained control problem. A second important result states that the set of randomized stationary policies provides a sufficient set for solving this MDP. It is important to note that, in contrast with the classical results of the literature, we do not assume the MDP to be transient or absorbing. More importantly, we do not impose the cost functions to be nonnegative or to be bounded below. Several examples are presented to illustrate our results.

scholarly journals The Expected Total Cost Criterion for Markov Decision Processes under Constraints: A Convex Analytic Approach

2012 ◽  
Vol 44 (3) ◽  
pp. 774-793 ◽  
Author(s):  
François Dufour ◽  
M. Horiguchi ◽  
A. B. Piunovskiy
Keyword(s):  
Optimal Control ◽  
Markov Decision Processes ◽  
Optimal Solution ◽  
Decision Processes ◽  
Linear Program ◽  
Occupation Measure ◽  
Stationary Policy ◽  
Total Cost ◽  
Markov Decision ◽  
Expected Total Cost

This paper deals with discrete-time Markov decision processes (MDPs) under constraints where all the objectives have the same form of expected total cost over the infinite time horizon. The existence of an optimal control policy is discussed by using the convex analytic approach. We work under the assumptions that the state and action spaces are general Borel spaces, and that the model is nonnegative, semicontinuous, and there exists an admissible solution with finite cost for the associated linear program. It is worth noting that, in contrast to the classical results in the literature, our hypotheses do not require the MDP to be transient or absorbing. Our first result ensures the existence of an optimal solution to the linear program given by an occupation measure of the process generated by a randomized stationary policy. Moreover, it is shown that this randomized stationary policy provides an optimal solution to this Markov control problem. As a consequence, these results imply that the set of randomized stationary policies is a sufficient set for this optimal control problem. Finally, our last main result states that all optimal solutions of the linear program coincide on a special set with an optimal occupation measure generated by a randomized stationary policy. Several examples are presented to illustrate some theoretical issues and the possible applications of the results developed in the paper.

scholarly journals The Expected Total Cost Criterion for Markov Decision Processes under Constraints: A Convex Analytic Approach

2012 ◽  
Vol 44 (03) ◽  
pp. 774-793 ◽  
Author(s):  
François Dufour ◽  
M. Horiguchi ◽  
A. B. Piunovskiy
Keyword(s):  
Optimal Control ◽  
Markov Decision Processes ◽  
Optimal Solution ◽  
Decision Processes ◽  
Linear Program ◽  
Occupation Measure ◽  
Stationary Policy ◽  
Total Cost ◽  
Markov Decision ◽  
Expected Total Cost

This paper deals with discrete-time Markov decision processes (MDPs) under constraints where all the objectives have the same form of expected total cost over the infinite time horizon. The existence of an optimal control policy is discussed by using the convex analytic approach. We work under the assumptions that the state and action spaces are general Borel spaces, and that the model is nonnegative, semicontinuous, and there exists an admissible solution with finite cost for the associated linear program. It is worth noting that, in contrast to the classical results in the literature, our hypotheses do not require the MDP to be transient or absorbing. Our first result ensures the existence of an optimal solution to the linear program given by an occupation measure of the process generated by a randomized stationary policy. Moreover, it is shown that this randomized stationary policy provides an optimal solution to this Markov control problem. As a consequence, these results imply that the set of randomized stationary policies is a sufficient set for this optimal control problem. Finally, our last main result states that all optimal solutions of the linear program coincide on a special set with an optimal occupation measure generated by a randomized stationary policy. Several examples are presented to illustrate some theoretical issues and the possible applications of the results developed in the paper.

scholarly journals The Linear Programming Approach to Reach-Avoid Problems for Markov Decision Processes

2017 ◽  
Vol 60 ◽  
pp. 263-285 ◽  
Author(s):  
Nikolaos Kariotoglou ◽  
Maryam Kamgarpour ◽  
Tyler H. Summers ◽  
John Lygeros
Keyword(s):  
Markov Decision Processes ◽  
Dimensional Space ◽  
Decision Processes ◽  
Linear Program ◽  
Control Synthesis ◽  
Programming Approach ◽  
Finite Dimensional Space ◽  
Infinite Dimensional ◽  
Finite Dimensional ◽  
Markov Decision

One of the most fundamental problems in Markov decision processes is analysis and control synthesis for safety and reachability specifications. We consider the stochastic reach-avoid problem, in which the objective is to synthesize a control policy to maximize the probability of reaching a target set at a given time, while staying in a safe set at all prior times. We characterize the solution to this problem through an infinite dimensional linear program. We then develop a tractable approximation to the infinite dimensional linear program through finite dimensional approximations of the decision space and constraints. For a large class of Markov decision processes modeled by Gaussian mixtures kernels we show that through a proper selection of the finite dimensional space, one can further reduce the computational complexity of the resulting linear program. We validate the proposed method and analyze its potential with numerical case studies.

scholarly journals Temporal concatenation for Markov decision processes

2021 ◽  
pp. 1-28
Author(s):  
Ruiyang Song ◽  
Kuang Xu
Keyword(s):  
Markov Decision Processes ◽  
Large Scale ◽  
Optimal Solution ◽  
Upper Bounds ◽  
Black Box ◽  
Decision Processes ◽  
Optimal Solutions ◽  
Wide Range ◽  
Markov Decision ◽  
Speed Up

We propose and analyze a temporal concatenation heuristic for solving large-scale finite-horizon Markov decision processes (MDP), which divides the MDP into smaller sub-problems along the time horizon and generates an overall solution by simply concatenating the optimal solutions from these sub-problems. As a “black box” architecture, temporal concatenation works with a wide range of existing MDP algorithms. Our main results characterize the regret of temporal concatenation compared to the optimal solution. We provide upper bounds for general MDP instances, as well as a family of MDP instances in which the upper bounds are shown to be tight. Together, our results demonstrate temporal concatenation's potential of substantial speed-up at the expense of some performance degradation.

scholarly journals New discount and average optimality conditions for continuous-time Markov decision processes

2010 ◽  
Vol 42 (04) ◽  
pp. 953-985 ◽  
Author(s):  
Xianping Guo ◽  
Liuer Ye
Keyword(s):  
Markov Decision Processes ◽  
Continuous Time ◽  
Average Cost ◽  
Nonnegative Solution ◽  
Decision Processes ◽  
Stationary Policy ◽  
Discounted Cost ◽  
Markov Decision ◽  
Optimal Stationary Policy ◽  
Bounded Below

This paper deals with continuous-time Markov decision processes in Polish spaces, under the discounted and average cost criteria. All underlying Markov processes are determined by given transition rates which are allowed to be unbounded, and the costs are assumed to be bounded below. By introducing an occupation measure of a randomized Markov policy and analyzing properties of occupation measures, we first show that the family of all randomized stationary policies is ‘sufficient’ within the class of all randomized Markov policies. Then, under the semicontinuity and compactness conditions, we prove the existence of a discounted cost optimal stationary policy by providing a value iteration technique. Moreover, by developing a new average cost, minimum nonnegative solution method, we prove the existence of an average cost optimal stationary policy under some reasonably mild conditions. Finally, we use some examples to illustrate applications of our results. Except that the costs are assumed to be bounded below, the conditions for the existence of discounted cost (or average cost) optimal policies are much weaker than those in the previous literature, and the minimum nonnegative solution approach is new.

scholarly journals New discount and average optimality conditions for continuous-time Markov decision processes

2010 ◽  
Vol 42 (4) ◽  
pp. 953-985 ◽  
Author(s):  
Xianping Guo ◽  
Liuer Ye
Keyword(s):  
Markov Decision Processes ◽  
Continuous Time ◽  
Average Cost ◽  
Nonnegative Solution ◽  
Decision Processes ◽  
Stationary Policy ◽  
Discounted Cost ◽  
Markov Decision ◽  
Optimal Stationary Policy ◽  
Bounded Below

This paper deals with continuous-time Markov decision processes in Polish spaces, under the discounted and average cost criteria. All underlying Markov processes are determined by given transition rates which are allowed to be unbounded, and the costs are assumed to be bounded below. By introducing an occupation measure of a randomized Markov policy and analyzing properties of occupation measures, we first show that the family of all randomized stationary policies is ‘sufficient’ within the class of all randomized Markov policies. Then, under the semicontinuity and compactness conditions, we prove the existence of a discounted cost optimal stationary policy by providing a value iteration technique. Moreover, by developing a new average cost, minimum nonnegative solution method, we prove the existence of an average cost optimal stationary policy under some reasonably mild conditions. Finally, we use some examples to illustrate applications of our results. Except that the costs are assumed to be bounded below, the conditions for the existence of discounted cost (or average cost) optimal policies are much weaker than those in the previous literature, and the minimum nonnegative solution approach is new.

scholarly journals Average optimality for Markov decision processes in borel spaces: a new condition and approach

2006 ◽  
Vol 43 (02) ◽  
pp. 318-334
Author(s):  
Xianping Guo ◽  
Quanxin Zhu
Keyword(s):  
Markov Decision Processes ◽  
Discrete Time ◽  
Existence Of Solutions ◽  
Sufficient Conditions ◽  
Decision Processes ◽  
Stationary Policy ◽  
Markov Decision ◽  
Optimal Stationary Policy ◽  
Optimality Inequality ◽  
Action Spaces

In this paper we study discrete-time Markov decision processes with Borel state and action spaces. The criterion is to minimize average expected costs, and the costs may have neither upper nor lower bounds. We first provide two average optimality inequalities of opposing directions and give conditions for the existence of solutions to them. Then, using the two inequalities, we ensure the existence of an average optimal (deterministic) stationary policy under additional continuity-compactness assumptions. Our conditions are slightly weaker than those in the previous literature. Also, some new sufficient conditions for the existence of an average optimal stationary policy are imposed on the primitive data of the model. Moreover, our approach is slightly different from the well-known ‘optimality inequality approach’ widely used in Markov decision processes. Finally, we illustrate our results in two examples.

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