Two Proof Methods For The Grafcet Language

: In this paper, we present two different methods to make proofs on the GRAFCET language. The first one is based on Transition Systems and the second one uses Polynomial Dynamical Systems. Theoretical and pratical aspects are presented. Key Words: Proof methods, GRAFCET, Transition Systems, Polynomial Dynamical Systems, Synchronous Methodology. 1. INTRODUCTION The proof of programs has become a new challenge for computer scientists. Indeed, it is no more sufficient to propose programming environments with nice ManMachine Interfaces and powerful tools, if the written programs can not be checked and formally proved. This requirement will be, in the next years, necessary in some particular fields such as aeronautics, industrial processes or real-time systems. Several proof tools over Transition Systems or Polynomial Dynamical Systems have been developped. We have applied some of its results to the programming language GRAFCET. After an overview of this language, we present two diff..

Many roads to flexibility. How large firms built autarchic regional production systems in France

This paper discusses the adjustment of large firms in France, in particular how they regionalized their production structures in the 1980s. Throughout the "Golden Age," large firms had geographically reorganized their activities: strategic planning remained in Paris, while the actual production was decentralized into the provinces, primarily to address cost and labour conflict issues. When the large firms faced a profitability crisis in the 1980s, and the traditional state-financed way out of the problems was no longer available, they saw in these proto-regional production systems a chance to become more competitive. They relied on the decentralization policies of the governments in the 1980s, and used the second-order effects of the new policies as a means to modernise their own operations