Jaroslav Fogel

A Survey of Verification Techniques for Solving the State Explosion Problem

Abstract There exists number of formal methods for modelling the finite state transition systems to this time. After the model development, the verification of the model’s properties is a promising step to the development of the correct model. The verification techniques are usually based on the reachability graph analysis, and for the large composite models they lead to the so called „state explosion problem“. In the paper, the various known verification techniques that address this problem are discussed.

An Object-Oriented Specification of a Control Logic for An FMS

Abstract The paper concerns with the application of object-oriented modelling to the development of real-time control software for FMS. Object- oriented model integrates the features of object-oriented database, features of real-time system and features of artificial intelligence aspects. The goal is to develop intelligent decision making logic for automatic creation of the control actions in both the standard and the nonstandard (error) situations. The knowledge is represented by the rules and the constraints. Three type of rules are described in the paper: process rules (create the dynamic model of the devices), production plan rules (define the production sequence of the technological operations), and expert knowledge rules (create reasoning model for solving the fault situations). The cooperation among these rules is also discussed in the paper.

Time Extension of Hierarchical State Machines

Abstract We present the time extension of the hierarchical state machines with real-time constructs as clocks, timed guards, and invariants. For timed hierarchical state machines we propose the compositional semantics of traces ensuring that the semantics of the model can be determined from the semantics of its components. Such semantics is proposed with the goal of its successive utilization in the design and verification of the model. At the end of the paper, we discussed the verification problem, and its decomposition to sub-problems with lower complexity as the consequence of the compositional semantics and component refinement using the rules of assume-guarantee reasoning.

Job Shop Scheduling Problem in Multi-Part Production System

Abstract The topic of the paper is the scheduling problem of jobs in multi-machine multi-part manufacturing systems. In the paper the approach to the creation of the scheduling algorithm using the multi-agent rules is described. In the simulation phase, graphical representation of the scheduling problem by the statecharts model is used to detect the conflict situations.

A Statecharts Approach to the Modelling of Discrete Manufacturing Systems

Abstract The paper shows a novel approach to the modelling of the production cells of discrete manufacturing by asynchronous version of a statecharts formalism. For the proposed model, the functional specification of the model based on the specification language of temporal logic is presented. The specified behaviours are translated into the syntax of statecharts as guarded constraints on the transitions firing. The proposed approach is demonstrated on an illustrative example of the working cell.

A Model Based Approach to the Supervisory Control of FMS

Abstract A model based approach to the supervisory control of FMS is presented in the paper. The proposed model comprises both the structural and the behavioural specification of the manufacturing system. The statecharts visual formalism is proposed for the structural specification, and temporal logic operators are proposed for the behavioural specification. The behavioural specification is translated into the statecharts syntax as the guarded constraints on the transition firing. The closed-loop control consists of monitoring module, controller module, synchronization block, and mentioned model of the system. The control decisions of the controller module are given according to the nominal path, and the actual state configuration of the model.

An Approach to Object-Oriented Modelling and Control of a Deds

Abstract The paper refers to the description of an object-oriented approach to the formalisation of parallel DEDS modelling tools. The goal of the presented approach is to develop a modelling framework that enables the modular and hierarchical construction of complex DEDS with the structured view of the underlying state space. The basic notions are defined, e.g., the state classes, the dynamic model of the objects and the operation of the parallel composition. The parallel composition of the objects’ models express the dynamic relations between objects of different classes in dependence on theirs states and occurred events. The method of the analysis of the model concerning to the reachability of the given configuration is also discussed. This point will be the further step of the research activity. At the end, a simple example and its program realisation in the C++ language is given.