Fundamental Study on Analysis and Synthesis of Discrete Event Systems
Project/Area Number  07680438 
Research Category 
GrantinAid for Scientific Research (C)

Section  一般 
Research Field 
情報システム学(含情報図書館学)

Research Institution  Toho University 
Principal Investigator 
NISHIMURA Yoshiyuki Toho University, Department of Science, Professor, 理学部, 教授 (70023075)

Project Fiscal Year 
1995 – 1996

Project Status 
Completed(Fiscal Year 1996)

Budget Amount *help 
¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1996 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1995 : ¥600,000 (Direct Cost : ¥600,000)

Keywords  discrete event system / Petri net / condition / event net / partial language / activity / net construction / stepwise refinement / 離散事象システム / ペトリネット / 条件 / 事象ネット / 半言語 / アクティビティ / ネットの合成 / 段階的詳細化 
Research Abstract 
In advance of the start of this research project, the author and his coworkers had defined the following condition/event net (C/E net) construction problem : given a partial language over a set of events as specification, construct a C/E net whose activity coincides with the specification. A variant of this is the problem to construct a C/E net which meets the specification using auxiliary events if necessary. The former and the latter problem will be called auxiliaryeventfree and auxiliaryeventintroduced problem, respectively. The author and his coworkers studied these problems and obtained several results including the fact that every solution of auxiliaryeventfree problem consists of atoms 'compatible' with the specification. Under these backgrounds the followings were obtained in this research project. 1. An algorithm for finding all atoms compatible with a given partial language was developed. 2. A method of finding the set of all solutions of auxiliaryeventfree C/E net construction problem was proposed. 3. A Petri net construction problem was defined as a generalization of auxiliaryeventintroduced C/E net construction problem and its solvability was discussed. 4. A new concept, hierarchical specification, was introduced for both auxiliaryeventfree and auxiliaryeventintroduced C/E net construction problems. It was shown that the concept permits stepwise refinement of construction processes. 5. A method to solve auxiliaryeventintroduced construction problems with finite specification was presented. A method for the same type of problems with periodical specification was also obtained.

Report
(4results)
Research Output
(10results)