David Parker
Senior Lecturer, University of Birmingham
[DFK+14] Klaus Draeger, Vojtěch Forejt, Marta Kwiatkowska, David Parker and Mateusz Ujma. Permissive Controller Synthesis for Probabilistic Systems. In Proc. 20th International Conference on Tools and Algorithms for the Construction and Analysis of Systems (TACAS'14), volume 8413 of LNCS, pages 531-546, Springer. April 2014. [pdf] [bib] [Presents permissive controller synthesis techniques for stochastic games, implemented in an extension of PRISM.]
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Notes: An extended version of this paper can be found in [DFK+14b]. The original publication is available at www.springerlink.com.
Abstract. We propose novel controller synthesis techniques for probabilistic systems modelled using stochastic two-player games: one player acts as a controller, the second represents its environment, and probability is used to capture uncertainty arising due to, for example, unreliable sensors or faulty system components. Our aim is to generate robust controllers that are resilient to unexpected system changes at runtime, and flexible enough to be adapted if additional constraints need to be imposed. We develop a permissive controller synthesis framework, which generates multi-strategies for the controller, offering a choice of control actions to take at each time step. We formalise the notion of permissiveness using penalties, which are incurred each time a possible control action is blocked by a multi-strategy. Permissive controller synthesis aims to generate a multi-strategy that minimises these penalties, whilst guaranteeing the satisfaction of a specified system property. We establish several key results about the optimality of multi-strategies and the complexity of synthesising them. Then, we develop methods to perform permissive controller synthesis using mixed integer linear programming and illustrate their effectiveness on a selection of case studies.