| 摘要: |
| 提出了时间Petri 网的混合语义模型,通过在变迁及其非冲突变迁集的最小上界处设置强制实施点,排除冲突变迁对变迁可实施性的影响,达到既能扩大模型调度范围又可保证任务调度时限性的目的,以解决现有语义模型在调度分析上的缺陷.进一步证明了混合语义模型的图灵等价性及标识可达性问题的不可判定性,然后界定了3 种语义模型的时间语言接受能力.最后提出了状态类分析方法,用于模型的可调度性分析和时间计算,并以一个柔性制造系统为例,比较和验证了3 种语义模型的调度分析能力. |
| 关键词: 时间Petri 网 混合语义 图灵等价性 不可判定性 调度分析 |
| DOI：10.3724/SP.J.1001.2011.04018 |
| 分类号: |
| 基金项目:国家自然科学基金(60803032, 60975049); 教育部新世纪优秀人才计划(NCET-10-0598); 上海市重点基础研究项目基金(09JC1414200); 上海市“曙光计划”; 上海市青年科技启明星计划(09QA1405900); 武汉大学软件工程国家重点实验室开放基金项目 |
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| Time Petri Net Model with Mixed Semantics |
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PAN Li1,2, DING Zhi-Jun2,3, GUO Guan-Qi1
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1.School of Information and Communication Engineering, Hu’nan Institute of Science and Technology, Yueyang 414006, China;2.Department of Computer Science and Technology, Tongji University, Shanghai 200092, China;3.State Key Laboratory of Software Engineering, Wuhan University, Wuhan 430072, China
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| Abstract: |
| This paper presents a time Petri net (TPN) model with mixed semantics that efficiently addresses the schedulability analysis problem of the existing semantics models. The proposed model associates each firable transition with a mandatory firing point that is set to the least upper bound of the transition and its non-conflicting transitions. This treatment not only eliminates the effect of conflicting transitions on the transition friability and extends the scheduling scope of the TPN model, but also ensures the time limit of the task scheduling. To determine the expressiveness of the mixed model, the study proves that the mixed semantics model has the power of Turing machines and its marking reachability problem is undecidable. The timed expressiveness of three semantics models with respect to timed language acceptance is also compared. A state class approach is then proposed for the scheduling analysis of the mixed model. Finally, a flexible manufacturing system is used as an example to compare the scheduling ability of three semantics models. |
| Key words: time Petri net mixed semantics turing equivalence undecidability schedulability analysis |
