共查询到19条相似文献,搜索用时 578 毫秒
1.
2.
Petri网有严格的数学定义,具有描述分布式通信计算系统的能力.通过分析网格系统的特点,高度抽象网格系统概念,基于Petri网原理,构造网格系统的库所和变迁,用有色Petri网系统给出网格系统的形式化定叉,并对相关概念进行了讨论. 相似文献
3.
Petri网是计算机异步成分之间进行通信的理论基础.Petri网的应用涉及计算机学科的各个领域.文中运用Petri网工具来对工作流技术进行了详细的分析与描述,并用一个例子来说明如何使用Petri网来描述工作流的各种同步关系以及流向,最后,文章还给出了一个由功能模型、数据/信息模型、组织模型、资源模型组成的工作流复合模型. 相似文献
4.
针对Petri网理论与方法在服务计算中的应用,从Web服务执行的角度,在定义Web服务组合的Petri网的基础上,给出Web服务组合的Petri网的自动生成方法.首先对Web服务的Petri网描述,通过利用Web服务的输入、输出等元素的本体定义为Petri网中相应库所元素添加语义标签,得到Web服务的Petri网的PNML(Petri net Markup Language)+OWL(Ontology Web Language)描述,其中PNML部分描述Petri网的网结构,OWL部分描述Petri网中各库所元素的语义标记;进一步,在已得到Web服务组合中各子Web服务之间输入/输出关联元素的基础上,确定各子Web服务的Petri网之间的可融合库所,通过执行可融合库所之间的库所融合操作,将各子Web服务的Petri网合并得到Web服务组合的Petri网,为Petri网相关理论与方法在服务计算中得到实际应用提供了必要的前提. 相似文献
5.
6.
利用时间约束Petri网进行项目绩效分析 总被引:1,自引:0,他引:1
时间Petri网(Time Petri Net)以及时延Petri网(Timed Petri Net)通过将时间约束引入到变迁中,广泛运用于任务调度以及性能分析,但是对于项目绩效分析所要求的关键路径、最短工期、成本分析等问题却无法有效解决.提出一种新的时间约束Petri网:将时间约束引入到库所中,在全局时钟的基础上,同时赋予Petri网的库所以延迟时间域和持续时间域两种时间约束,并且为T→P流关系的权函数赋予有色资源属性.给出时间约束Petri网的形式化定义,定义了变迁的发生规则,并引入状态类来计算状态的成本空间,给出状态类的计算方法.最后结合一个实例说明了利用时间约束Petri网进行项目的绩效分析的可行性.并用双色甘特图对时间约束Petri网的可达标识进行表述. 相似文献
7.
8.
为了优化火电厂管控信息系统,提出了基于时序Petri网的火电厂管控信息系统模型研究.首先提出了时序Petri网的分层建模方法,并给出了时序Petri网对复杂系统的建模步骤;其次,建立了整个火电厂管控信息系统的时序Petri网模型;再次,为了更好地分析和优化Petri网模型,对其进行了简化;最后,证明了简化后的时序Petri网大大减少了库所和变迁的数量并保持了原网的功能性. 相似文献
9.
10.
11.
基于有色网的多Agent计划建模 总被引:1,自引:0,他引:1
有色网能够描述资源和操作的具体语义。首先,由于计划中的操作和状态的个数的有限性,与有色网的元素个数有限性约束完全一致。另外,计划中的动作与有色网中的变迁语义类似,以及计划中的操作和状态和有色网中的库所语义非常类似。因此,有色网应用到计划的形式化中,有其独特的优势。本文根据约定的前提条件,计划建模从操作、状态和交互3个方面来具体实现,并给出了建模方法。计划的规范描述、有效性验证以及计划的模拟都可以直接应用经典Petri网或有色网的理论技术。 相似文献
12.
Multi-level multi-agent systems (MASs) with dynamic structure are widely used in solving important applied problems in telecommunication, transportation, social, and other systems. Therefore, ensuring correct behavior of such systems is an actual and important task. One of the most error-prone stages of system development in the framework of model-oriented approach is the implementation stage, in the course of which a program code is constructed based on the model developed. This paper presents an algorithm for automated translation of MAS models represented as nested Petri nets into systems of distributed components. Nested Petri nets are the extension of Petri nets in the framework of the nets-within-nets approach, which assumes that tokens in a Petri net may themselves be Petri nets, possess autonomous behavior, and interact with other tokens of the net. This makes it possible to model MASs with dynamic structure in a natural way. The translation presented in this paper preserves distribution level and important behavioral properties (safety, liveness, and conditional liveness) of the original model and ensures fairness of the target system execution. The use of such translation makes it possible to automate construction of distributed MASs by models of nested Petri nets. As a test example, translation of nested Petri nets into systems of distributed components was implemented on the basis of the EJB component technology. 相似文献
13.
14.
基于工作流网的实时协同系统模拟技术 总被引:10,自引:0,他引:10
基于Petri网和工作流的概念,提出一种实时协同系统的形式化模拟与分析技术——逻辑工作流网,逻辑工作流网是抑制弧Petri网和高级Petri网的抽象和扩展,其变迁的输入/输出受逻辑表达式的约束,它与一般工作流网相比,能够在一定程度上缓解状态空间爆炸问题,且便于系统设计人员掌握和使用,该文分析了逻辑工作流网的若干性质及组合网的性质继承问题,并以网上企业销售系统为例,说明逻辑工作流网在实时协同系统模拟分析中的应用。 相似文献
15.
16.
The various kinds of access decision dependencies within a predicate-based model of database protection are classified according to cost of enforcement. Petri nets and some useful extensions are described. Extended Petri nets are used to model the flow of messages and data during protection enforcement within MULTISAFE, a multimodule system architecture for secure database management. The model demonstrates that some of the stated criteria for security are met within MULTISAFE. Of particular interest is the modeling of data dependent access conditions with predicates at Petri net transitions. Tokens in the net carry the intermodule messages of MULTISAFE. Login, authorization, and database requests are traced through the model as examples. The evaluation of complex access condition predicates is described for the enforcement process. Queues of data and queues of access condition predicates are cycled through the net so that each data record is checked against each predicate. Petri nets are shown to be a useful modeling tool for database security. 相似文献
17.
Model and control holonic manufacturing systems based on fusion of contract nets and Petri nets 总被引:1,自引:0,他引:1
Fu-Shiung Hsieh Author Vitae 《Automatica》2004,40(1):51-57
Holonic manufacturing systems (HMS) can be modeled as multi-agent systems to which contract net protocol can be effectively and robustly applied. However, the lack of analysis capability of contract nets makes it difficult to avoid undesirable states such as deadlocks in HMS. This paper presents a framework to model and control HMS based on fusion of Petri net and multi-agent system theory. The main results include: (1) a multi-agent model and a collaboration process to form commitment graphs in HMS based on contract net protocol, (2) a procedure to convert commitment graph to collaborative Petri net (CPN), and (3) feasible conditions and collaborative algorithms to award contracts in HMS based on CPNs. 相似文献
18.