Concurrent modeling language (CML) for discrete process modeling, simulation and control

Abstract

Modern manufacturing systems can be viewed as distributed concurrent discrete processes, using extensive communication internally and with the environment. The concurrency and reactive nature of the system make it difficult to model and analyze correctly. This paper presents a genuine high level and concurrent modeling language, CML, that can be used for modeling and control of manufacturing processes. In addition, it can be used for simulation and analysis of the system's operation. The CML language is based on fiat concurrent prolog which is a declarative concurrent logic programming language, therefore, highly expressive, and theoretically sound.

Reactive Scheduling in Real Time Production Control

“…For constructing valid models of manufacturing processes by the design and simulation of the real-time discrete controlj scheduling logic, the models should represent the discrete event evolution of the system and its admissible trajectories. Discrete event systems can be further dichotomised [12] in many ways: sequential systems versus concurrent ones, deterministic versus nondeterministic systems, synchronous versus asynchronous systems, etc. However, a more important classification is reactive versus transformational systems [69].…”

“…Modelling reactive systems is inherently difficult: there is no simple transformation that can represent the system. The reactive system is usually hierarchical, and its components are concurrently and asynchronously active, like operating manufacturing systems [12]. The communication among the components is a crucial part of the model, and the variety of states that the system can have is very large.…”

“…CML language is reactive in the sense [12] that system components are represented as computational processes that alive concurrently, each reacting to its inputs. During the model operation all the activities are executed in parallel, thus generating a reactive model of a system.…”

“…The concurrency and reactive nature of the system make it difficult to model and analyse correctly. CML, as described in [12], is a high level and concurrent modelling language for the simulation modelling and control of manufacturing processes, particularly useful for simulation and analysis of the manufacturing system operation. The CML language is based on Aat concurrent Prolog, which is a declarative concurrent logic programming language, therefore, highly expressive and theoretically sound.…”