共查询到19条相似文献,搜索用时 437 毫秒
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针对柔性制造系统FMS(Flexible manufacturing system)建模特点,提出了UML-OOPN集成建模方法。该方法是用UML(the Unified Modeling Language)建立柔性制造系统FMS(Flexible manufacturing system)模型,然后将该模型映射为面向对象Petri网OOPN(Object-Oriented Petri Nets)网模型,通过Petri网模型的分析和仿真,其结果可用于修正和改进模型设计。 相似文献
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时间约束Petri网的可调度性分析研究 总被引:3,自引:0,他引:3
1 引言时间约束Petri网(Timing Constraint PetriNets,TCPN’s)是具有广义时间约束的Petri网,它综合了时间Petri网)(Time Petri Nets)和赋时Petri网(Timed Petri Nets)的共同特点,具有经典Petri网的理论基础和额外的时间约束能力。在实时系统建模中,它可对其它与时间有关的Petri网所不能描述的冲突结构进行建模和分析。TCPN’s使用弱触发规则,即:使能的变迁可触发也可不触发,完全由调度者决 相似文献
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为提高软件即服务(SaaS)应用中资源的访问效率,提出支持SaaS服务重要特征的负载均衡策略。首先,结合SaaS服务的多租户和高度可伸缩两大特性,提出一种基于租户请求分流、在局部和全局两个层次伸缩的负载均衡策略;其次,对所提出负载均衡策略用Petri网进行建模并仿真;最后,将提出的负载均衡策略与轮询(RR)、随机和改进的最小连接(ILCS)负载均衡算法在总体响应时间和总吞吐量两方面进行比较。实验结果表明:在请求速率达到500请求/秒后,所提策略的总体响应时间和总吞吐量趋于稳定并优于另外三种算法。 相似文献
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密码协议是安全共享网络资源的机制和规范,是构建网络安全环境的基石,其安全性对整个网络环境的安全起着至关重要的作用。提出了采用Colored Petri Nets(CPN,着色Petri网)分析密码协议的新方法。采用新方法对TMN协议的多次并发会话通信进行形式化建模,模型依据会话配置和会话顺序进行功能单元划分,采用on-the-fly方法生成攻击路径。采用状态空间搜索技术,发现了该协议的多次并发会话不安全状态,并获得了新的攻击模式。 相似文献
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随着SaaS(Software as a Service,即SaaS)应用交付平台租户数目及信息数据量呈几何曲线性增长,平台数据管理正处于由单数据节点往云中多数据节点转变的必然阶段,本文以软件即服务应用交付平台中多租户云数据管理为目标,对SaaS平台数据模型、云中放置策略、租户索引等进行了深入研究,提出一种SaaS平台多租户虚拟化方式及高效映射转换的数据分层模型,通过租户无关的应用数据模型为开发商屏蔽多租户云数据管理技术细节,通过租户逻辑模型支持租户按需定制数据模式以及各业务系统数据之间的共享关系,通过逻辑存储模型为平台运营商屏蔽了云中数据节点伸缩技术,解决了SaaS应用生命周期云数据管理技术瓶颈问题. 相似文献
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潘峰 《计算机应用与软件》2015,(3):7-10,30
针对软件动态行为复杂难以建模,且可靠性难以评估的问题,提出一种基于随机有色Petri网SCPN(Stochastic Colored Petri Net)的软件可靠性建模与分析方法。在建立软件可靠性分析的元结构模型的基础上,分别建立软件可靠性分析的串联结构模型和并联结构模型,有效地描述了软件的静态结构和动态行为。以某工厂采购系统为目标系统,以Time NET4.0为平台,建立其基于SCPN的软件可靠性分析模型,仿真验证了所提方法的正确性和有效性。该方法可以为软件可靠性的早期评估提供理论指导。 相似文献
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Petri网是一种应用非常广泛的建模工具。首先给出了基本Petri网的概念,在此基础上对多种Petri网进行了广泛的研究,包括时间因素Petri网、有色Petri网、面向对象Petri网、模糊Petri网及受控Petri网,并针对每种Petri网的特点和应用范围进行了讨论,提出了Petri网当前发展的方向和急需解决的热点问题。 相似文献
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Mohamed A. Ameedeen Behzad Bordbar Rachid Anane 《Journal of Computer and System Sciences》2011,77(2):332-347
Among the factors that contribute to the inherent complexity of the software development process is the gap between the design and the formal analysis domains. Software design is often considered a human oriented task while the analysis phase draws on formal representation and mathematical foundations. An example of this dichotomy is the use of UML for the software design phase and Petri Nets for the analysis; a separation of concerns that leads to the creation of heterogeneous models. Although UML is widely accepted as a language that can be used to model the structural and behavioural aspects of a system, its lack of mathematical foundations is seen as a serious impediment to rigorous analysis. Petri Nets on the other hand have a strong mathematical basis that are well suited for formal analysis; they lack however the appeal and the ease-of-use of UML. A pressing concern for software developers is how to bridge the gap between these domains and allow for model interoperability and the integration of different toolsets across them, and thus reduce the complexity of the software development process. The aim of this paper is to present a Model Driven Development (MDD) model transformation which supports a seamless transition between UML and Petri Nets. This is achieved by model interoperability from UML Sequence Diagrams to Petri Nets and supported by tool integration. The model transformation framework allows a software system to be designed in terms of UML Sequence Diagrams and subjected to formal analysis by taking advantage of the strong mathematical framework of Petri Nets. The behaviour of a Personal Area Network will be used to illustrate the proposed approach and to highlight model interoperability and tool integration through the design, the transformation and the analysis phases. 相似文献
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In this paper,the Extended Strong,Asymmetric Choice NetsⅡ(ESACNⅡ),a subclass of Asymmetric Choice Nets(ACN) including Extended Free Choice Nets(EFCN) and Strong Asymmetric Choice Nets Ⅱ(SACNⅡ),is presented.A necessary and sufficient condition for liveress of ESACNⅡis proposed.Moreover,a criterion is introduced,which is necessary and sufficient for judgement of liveness and boundedness of ESACNⅡ,Meanwhile a polynomial time algoirithm is given to decide liveness and boundedness for ESACNⅡ. 相似文献
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基于Time Petri Nets的实时系统资源冲突检测 总被引:2,自引:1,他引:1
Time Petri Nets在实时系统的建模和性能分析中得到广泛应用,而冲突是Petri网及其扩展模型的重要行为,解决冲突是正确分析模型动态行为的关键.目前随机Petri网、混合Petri网和区间速率连续Petri网的冲突检测方法由于没有考虑到时间约束因此无法在TPN网中使用.时间约束的引入使得Time Petri Nets模型的使能和触发语义比Petri网模型的语义复杂,冲突检测变得更加困难.为了计算冲突发生的时间和概率,首先根据时间约束,给出了变迁持续使能时延迟区间的计算方法,并证明了该方法的合理性和完备性;然后在此基础上定义并证明了Time Petri Nets模型中不冲突的检测方法;并提出了Time Petri Nets模型的冲突检测方法,给出了冲突时间区间和变迁实施概率的计算方法;最后通过实例验证说明了该方法的正确性和有效性. 相似文献
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统一建模型语言(UML)已经成为软件系统的分析与设计的标准工具,但由它扩充而成的代理统一建模型语言(AUML)还没变成一个标准,目前的AUML规格说明还有很多的局限性,还不能胜任多代理系统的开发.Petri网是仿真、验证软件系统执行的正确性与有效性的形式化工具.本文主要分析当前AUML规格说明和Petri网概念.找出它们之间的结合点,提出用Petri网扩充AUML的方法.将其应用于多代理系统的开发,就能实施之前运用Petri网进行系统的正确性与有效性验证. 相似文献
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The aim of this paper is to develop a unified approach for deriving complexity results for problems concerning conflict-free
Petri nets. To do so, we first define a class of formulas for paths in Petri nets. We then show that answering the satisfiability
problem for conflict-free Petri nets is tantamount to solving a system of linear inequalities (which is known to be in P).
Since a wide spectrum of Petri net problems (including various fairness-related problems) can be reduced to the satisfiability
problem in a straightforward manner, our approach offers an umbrella under which many Petri net problems for conflict-free
Petri nets can be shown to be solvable in polynomial time. As a side-product, our analysis provides evidence as to why detecting
unboundedness for conflict-free Petri nets is easier (provided P ≠ NP) than for normal and sinkless Petri nets (which are
two classes that properly contain conflict-free Petri nets).
A preliminary version was presented at the 14th International Conference on Application and Theory of Petri Nets, Chicago,
IL, USA, June 1993. 相似文献