Model abstraction of nondeterministic finite state automata in supervisor synthesis

Blockingness is one of the major obstacles that need to be overcome in the Ramadge-Wonham supervisory synthesis paradigm, especially for systems of industrial size. Owing to the high computational complexity, synthesizing a nonblocking supervisor for a large scale system is never easy, if still possible. In this paper we attempt to solve this synthesis problem by using abstractions. We first introduce a new abstraction operation, which preserves the nonblocking property. Then we describe how to synthesize supervisors by using abstractions of relevant automata so that the high computational complexity associated with the synchronous product described in the Ramadge-Wonham supervisory control theory (SCT) may be avoided

Model abstraction of nondeterministic finite state automata in supervisor synthesis

Blockingness is one of the major obstacles that need to be overcome in the Ramadge-Wonham supervisory synthesis paradigm, especially for systems of industrial size. Owing to the high computational complexity, synthesizing a nonblocking supervisor for a large scale system is never easy, if still possible. In this paper we attempt to solve this synthesis problem by using abstractions. We first introduce a new abstraction operation, which preserves the nonblocking property. Then we describe how to synthesize supervisors by using abstractions of relevant automata so that the high computational complexity associated with the synchronous product described in the Ramadge-Wonham supervisory control theory (SCT) may be avoided

An algorithm for weak synthesis observation equivalence for compositional supervisor synthesis

This paper proposes an algorithm to simplify automata in such a way that compositional synthesis results are preserved in every possible context. It relaxes some requirements of synthesis observation equivalence from previous work, so that better abstractions can be obtained. The paper describes the algorithm, adapted from known bisimulation equivalence algorithms, for the improved abstraction method. The algorithm has been implemented in the DES software tool Supremica and has been used to compute modular supervisors for several large benchmark examples. It successfully computes modular supervisors for systems with more than 1012 reachable states

Parallelle processen, machines en netwerken

Tegenwoordig zijn wij omgeven door inrichtingen met ingebedde computers (embedded systemen). De inrichting zorgt voor de uitvoering van de bewerkingsprocessen, de computers zorgen ervoor dat de processen volgens een gedefinieerde specificatie verlopen. In het college belicht professor Rooda het traditionele ontwerpen. Door de komst van de microprocessor is het mogelijk om andere ontwerpmethoden te hanteren om zo tot een kwalitatief betere en tevens snellere realisatie van industriële systemen te komen. Professor Rooda introduceert een formalisme dat geschikt is voor het ontwerpen, het analyseren, het realiseren en het besturen van dergelijke systemen. Hij zal vervolgens uiteenzetten hoe de besturing, met behulp van de modellen van de machine en van de modellen van de bijbehorende besturingseisen, automatisch gegenereerd kan worden. Hij zal hier met een industriële casus nader op ingaan. Daarna behandelt professor Rooda een aggregatiemethode voor het berekenen van de doorzet en de productdoorlooptijd in (stochastische) netwerken. Tot slot passeren netwerken met zogenaamde schakelende machines de revue

Compositional and Abstraction-Based Approach for Synthesis of Edit Functions for Opacity Enforcement

This paper develops a novel compositional and abstraction-based approach to synthesize edit functions for opacity enforcement in modular discrete event systems. Edit functions alter the output of the system by erasing or inserting events in order to obfuscate the outside intruder, whose goal is to infer the secrets of the system from its observation. We synthesize edit functions to solve the opacity enforcement problem in a modular setting, which significantly reduces the computational complexity compared with the monolithic approach. Two abstraction methods called opaque observation equivalence and opaque bisimulation are first employed to abstract the individual components of the modular system and their observers. Subsequently, we propose a method to transform the synthesis of edit functions to the calculation of modular supremal nonblocking supervisors. We show that the edit functions synthesized in this manner correctly solve the opacity enforcement problem

Model abstraction of nondeterministic finite-state automata in supervisor synthesis

Blockingness is one of the major obstacles that need to be overcome in the Ramadge-Wonham supervisory synthesis paradigm, especially for large systems. In this paper we propose an abstraction technique to overcome this difficulty. We first provide details of this abstraction technique, then describe how it can be applied to a supervisor synthesis problem, where plant models are nondeterministic but specifications and supervisors are deterministic. We show that a nonblocking supervisor for an abstraction of a plant under a specification is guaranteed to be a nonblocking supervisor of the original plant under the same specification. The reverse statement is also true, if we impose an additional constraint in the choice of the alphabet of abstraction, i.e. every event, which is either observable or labels a transition to a marker state, is contained in the alphabet of abstraction

Model abstraction of nondeterministic finite-state automata in supervisor synthesis Citation for published version (APA): Model Abstraction of Nondeterministic Finite-State Automata in Supervisor Synthesis

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