COSY: Language Definition for Modeling and Simulation of Mixed Continuous and Discrete Processes

Introduction

At that time, there existed no simulation language that would lend itself to a clean and complete description of such processes. First attempts to designing such a tool had been reported by Fahrland and Golden in the early seventies. However, these language designs had never been completed.

As part of my PhD dissertation, I first developed a Fortran-based library of subroutines, called GASP-V, that made it possible to simulate correctly and efficiently mixed continuous and discrete processes. GASP-V was used successfully by several research groups in projects of theirs.

The aim of COSY was to simplify the modeling environment. A preprocessor should be developed that would preprocess COSY programs into GASP-V. However, I didn't have the necessary resources to develop that preprocessor by myself.

Only in the early eighties, a slimmed-down version of COSY was implemented by the British Ministry of Defence under the name MODSIM.

Although MODSIM was developed further in later years, I lost interest in this development, since in the mean time, the Dymola/Modelica modeling environment had become available as a more flexible alternative.

Historical Development

• In 1977, COSY was designed as a modeling frontend to the simulation software GASP-V. Although no preprocessor for COSY was available yet, the language definition was fully tested and debugged by means of a general-purpose parser program that had also been developed as part of my PhD dissertation.

• In 1982, Nigel Baker of the British Ministry of Defence began to implement a subset of the COSY simulation language definition under the name MODSIM. A first version of MODSIM was made available in 1984.

Most Important Publications

1. Cellier, F.E. (1979), Combined Continuous/Discrete System Simulation by Use of Digital Computers: Techniques and Tools, Swiss Federal Institute of Technology, ETH Zürich, Switzerland.

2. Cellier, F.E. and A.P. Bongulielmi (1979), The COSY Simulation Language, Proc. 9^th IMACS Congress on Simulation of Systems, Sorrento, Italy, pp.271-281.

3. Cellier, F.E. (1986), Combined Continuous/Discrete Simulation - Applications, Techniques and Tools, Proc. Winter Simulation Conference, Washington, DC, pp.24-33.

Sponsors

• ETH Zürich
• British Ministry of Defence

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