In this paper, we are interested in the control of a particular class of Concurrent Discrete Event Systems defined by a collection of components that interact with each other. We investigate the computation of the supremal controllable language contained in the one of the specification. We do not adopt the decentralized approach. Instead, we have chosen to perform the control on some approximations of the plant derived from the behavior of each component. The behavior of these approximations is restricted so that they respect a new language property for discrete event systems called partial controllability condition that depends on the specification. It is shown that, under some assumptions, the intersection of these “controlled approximations” corresponds to the supremal controllable language contained in the specification with respect to the plant. This computation is performed without having to build the whole plant, hence avoiding the state space explosion induced by the concurrent nature of the plant.

In this paper, the supervisory control of a class of Discrete Event Systems is investigated. Discrete event systems are modeled either by a collection of Finite State Machines that behave asynchronously or by a Hierarchical Finite State Machine. The basic problem of interest is to ensure the invariance of a set of particular configurations in the system. When the system is modeled as asynchronous FSMs, we provide algorithms that, based on a particular decomposition of the set of forbidden configurations, solve the control problem locally (i.e. on each component without computing the whole system) and produce a global supervisor ensuring the desired property. We then provide sufficient conditions under which the obtained controlled system is non-blocking. This kind of objectives may be useful to perform dynamic interactions between different parts of a system. Finally, we apply these results to the case of

We describe the extension of a reactive programming language with a behavioral contract construct. It is dedicated to the programming of reactive control of applications in embedded systems, and involves principles of the supervisory control of discrete event systems. Our contribution is in a language approach where modular discrete controller synthesis (DCS) is integrated, and it is concretized in the encapsulation of DCS into a compilation process. From transition system specifications of possible behaviors, DCS automatically produces controllers that make the controlled system satisfy the property given as objective. Our language features and compiling technique provide correctness-by-construction in that sense, and enhance reliability and verifiability. Our application domain is adaptive and reconfigurable systems: closed-loop adaptation mechanisms enable flexible execution of functionalities

In this paper, we are interested in the control of a particular class of Concurrent Discrete Event Systems defined by a collection of components that interact with each other. We investigate the computation of the supremal controllable language contained in the one of the specification. We do not adopt the decentralized approach. Instead, we have chosen to perform the control on some approximations of the plant derived from the behavior of each component. The behavior of these approximations is restricted so that they respect a new language property for discrete event systems called partial controllability condition that depends on the specification. It is shown that, under some assumptions, the intersection of these "controlled approximations" corresponds to the supremal controllable language contained in the specification with respect to the plant. This computation is performed without having to build the whole plant, hence avoiding the state space explosion induced by the concurrent nature of the plant.

Abstract — It is well known that the nonblocking supervisory control problem is NP-hard, subject in particular to state space explosion that is exponential in the number of system components. In this paper we propose to manage complexity by organizing the system as a State Tree Structure (STS). STS are an adaptation of state charts to supervisory control theory. Based on STS we present an efficient recursive algorithm that can perform nonblocking supervisory control design (in reasonable time and memory) for systems of state size 10 24 and higher.

Hierarchical Interface-based Supervisory Control (HISC) decomposes a discreteevent system (DES) into a high-level subsystem which communicates with n ≥ 1 low-level subsystems, through separate interfaces which restrict the interaction of the subsystems. It provides a set of local conditions that can be used to verify global conditions such as nonblocking and controllability. As each clause of the definition can be verified using a single subsystem, the complete system model never needs to be stored in memory, offering potentially significant savings in computational resources. Currently, a designer must create the supervisors for a HISC system himself, and then verify that they satisfy the HISC conditions. In this thesis, we develop a synthesis method that respects the HISC hierarchical structure. We replace the supervisor for each level by a corresponding specification DES. We then do a per level synthesis to construct for each level a maximally permissive supervisor that satisfies the corresponding HISC conditions. We define

Abstract — This paper studies the nonblocking check used in supervisory control of discrete event systems and its limitations. Different examples with different liveness requirements are discussed. It is shown that the standard nonblocking check can be used to specify most requirements of interest, but that it lacks expressive power in a few cases. A generalised nonblocking check is proposed to overcome the weakness, and its relationship to standard nonblocking is explored. Results suggest that generalised nonblocking, while having the same useful properties with respect to synthesis and compositional verification, can provide for more concise problem representations in some cases. I.

Abstract — This paper proposes a compositional approach to verify the generalised nonblocking property of discrete-event systems. Generalised nonblocking is introduced in [1] to overcome weaknesses of the standard nonblocking check in discreteevent systems and increase the scope of liveness properties that can be handled. This paper addresses the question of how generalised nonblocking can be verified efficiently. The explicit construction of the complete state space is avoided by first composing and simplifying individual components in ways that preserve generalised nonblocking. The paper extends and generalises previous results about compositional verification of standard nonblocking and lists a new set of computationally feasible abstraction rules for standard and generalised nonblocking. I.

We study distributed control design for discrete-event systems (DES) in the framework of supervisory control theory. Our DES comprise multiple agents, acting independently except for specifications on ‘global ’ behavior. The central problem investigated is how to synthesize ‘local ’ controllers for individual agents such that the resultant controlled behavior is identical with that achieved by global supervision. The investigation is carried out with both language- and state-based models. In the language-based setting, a supervisor localization algorithm is developed that solves the problem in a top-down fashion: first, compute a global supervisor, then decompose it into local controllers. For large-scale DES where a global supervisor might not be feasibly computable owing to state explosion, a decomposition-aggregation solution procedure is established. In the state-based setting, specifically that of ‘state tree structures ’ (STS), a counterpart supervisor localization algorithm is developed having potential to exploit the known efficiency of STS for large-DES control design. ii Acknowledgements It is my great honour and pleasure to study under the supervision of Professor W.M.

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