共查询到20条相似文献,搜索用时 15 毫秒
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Aurélien Naldi Elisabeth RemyDenis Thieffry Claudine Chaouiya 《Theoretical computer science》2011,412(21):2207-2218
To cope with the increasing complexity of regulatory networks, we define a reduction method for multi-valued logical models.Starting with a detailed model, we use decision diagrams to compute reduced models by iteratively “removing” regulatory components. To keep a consistent dynamical behaviour, the logical rules associated with the targets of each removed node are actualised to account for the (indirect) effects of its regulators.This construction of reduced models preserves crucial dynamical properties of the original model, including stable states and more complex attractors. In this respect, the relationship between the attractor configuration of the original model and those of reduced models is formally established. We further analyse the issue of attractor reachability.Finally, we illustrate the flexibility and efficiency of the proposed reduction method by its application to a multi-valued model of the fly segment polarity network, which is involved in the control of segmentation during early embryogenesis. 相似文献
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Both the combination and sequential switching function, also called switching circuits, can be represented by the binary code with Boolean algebra and Finite State Machine (FSM). The basic elements of Petri net graph, such as place nodes, transition nodes, arcs, and tokens are used to frame the OR, NOT, and NOR logic function. Furthermore, to illustrate AND, and NAND switching function using the foregoing switching function, which is implemented by the Petri net graph. The main purpose of the paper is to prove ours hypothesis that the most logic function can be represented by the Petri net graph. Ultimately, our assumptions are complemented trustily. 相似文献
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Haas P.J. Shedler G.S. 《IEEE transactions on pattern analysis and machine intelligence》1989,15(4):381-393
In the context of discrete event simulation, the marking of a stochastic Petri net (SPN) corresponds to the state of the underlying stochastic process of the simulation and the firing of a transition corresponds to the occurrence of an event. A study is made of the modeling power of SPNs with timed and immediate transitions, showing that such Petri nets provide a general framework for simulation. The principle result is that for any (finite or) countable state GSMP (generalized semi-Markov process) there exists an SPN having a marking process that mimics the GSMP in the sense that the two processes (and their underlying general state-space Markov chains) have the same finite dimensional distributions 相似文献
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Dwyer M.B. Clarke L.A. 《IEEE transactions on pattern analysis and machine intelligence》1996,22(11):794-811
We explore a property-independent, coarsened, multilevel representation for supporting state reachability analysis for a number of different properties. This multilevel representation comprises a reachability graph derived from a highly optimized Petri net representation that is based on task interaction graphs and associated property-specific summary information. This highly optimized representation reduces the size of the reachability graph but may increase the cost of the analysis algorithm for some types of analyses. We explore this tradeoff. To this end, we have developed a framework for checking a variety of properties of concurrent programs using this optimized representation and present empirical results that compare the cost to an alternative Petri net representation. In addition, we present reduction techniques that can further improve the performance and yet still preserve analysis information. Although worst-case bounds for most concurrency analysis techniques are daunting, we demonstrate that the techniques that we propose significantly broaden the applicability of reachability analyses 相似文献
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为便于表示模糊空间Petri网的状态变迁规则,根据空间关联影响区域分布现实特点,提出了空间模糊Petri网中的状态关联影响规则、变迁关联影响规则和多阈值激活规则。依据模糊产生式规则的特点,详细描述了10种具体的推理规则和表示组件,并以实例加以说明。在此基础上,结合模糊空间Petri网的特点提出了动态推理过程算法,可以实现各种空间状态规则因子的转化。动态推理的过程不仅可以获取某种“结果”,而且可以挖掘基于空间位置关联的中间状态及引起中间状态变化的事件,可以有效地指导风险过程预测和控制。 相似文献
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提出一种在某些库所中带有标识的模糊Petri网模型来进行知识表示。为了获得更多的加权模糊产生式规则的信息,在知识表示的过程中考虑了权值,确定性因子,阈值等参数。这种模糊Petri网充分利用了Petri网的并行处理能力。随着带标识的模糊Petri网的运行,网中标识的变化可以标记加权模糊推理的运行。通过文中给出的基于相似性测度的计算方法可以更加高效地计算出多层加权模糊推理的推理结果。 相似文献
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Model checking based on Petri net unfoldings is an approach widely applied to cope with the state space explosion problem. In this paper, we propose a new condensed representation of a Petri net’s behaviour called merged processes, which copes well not only with concurrency, but also with other sources of state space explosion, viz sequences of choices and non-safeness. Moreover, this representation is sufficiently similar to the traditional unfoldings, so that a large body of results developed for the latter can be re-used. Experimental results indicate that the proposed representation of a Petri net’s behaviour alleviates the state space explosion problem to a significant degree and is suitable for model checking.V. Khomenko is a Royal Academy of Engineering/Epsrc Research Fellow supported by the RAEng/Epsrc grant EP/C53400X/1 (Davac).M. Koutny is supported by the EC IST grant 511599 (Rodin).W. Vogler is supported by the DFG-project STG-Dekomposition VO 615/7-1 相似文献
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Modeling and formal verification of embedded systems based on a Petri net representation 总被引:2,自引:0,他引:2
In this paper we concentrate on aspects related to modeling and formal verification of embedded systems. First, we define a formal model of computation for embedded systems based on Petri nets that can capture important features of such systems and allows their representation at different levels of granularity. Our modeling formalism has a well-defined semantics so that it supports a precise representation of the system, the use of formal methods to verify its correctness, and the automation of different tasks along the design process. Second, we propose an approach to the problem of formal verification of embedded systems represented in our modeling formalism. We make use of model checking to prove whether certain properties, expressed as temporal logic formulas, hold with respect to the system model. We introduce a systematic procedure to translate our model into timed automata so that it is possible to use available model checking tools. We propose two strategies for improving the verification efficiency, the first by applying correctness-preserving transformations and the second by exploring the degree of parallelism characteristic to the system. Some examples, including a realistic industrial case, demonstrate the efficiency of our approach on practical applications. 相似文献
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This article combines Bayes’ theorem with flows of probabilities, flows of evidences (likelihoods), and fundamental concepts
for learning Bayesian networks as biological models from data. There is a huge amount of biological applications of Bayesian
networks. For example in the fields of protein modeling, pathway modeling, gene expression analysis, DNA sequence analysis,
protein–protein interaction, or protein–DNA interaction. Usually, the Bayesian networks have to be learned (statistically
constructed) from array data. Then they are considered as an executable and analyzable model of the data source. To improve
that, this work introduces a Petri net representation for the propagation of probabilities and likelihoods in Bayesian networks.
The reason for doing so is to exploit the structural and dynamic properties of Petri nets for increasing the transparency
of propagation processes. Consequently the novel Petri nets are called “probability propagation nets”. By means of examples
it is shown that the understanding of the Bayesian propagation algorithm is improved. This is of particular importance for
an exact visualization of biological systems by Bayesian networks. 相似文献
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In this paper, we develop a general technique for truncating Petri net unfoldings, parameterized according to the level of information about the original unfolding one wants to preserve. Moreover, we propose a new notion of completeness of a truncated unfolding. A key aspect of our approach is an algorithm-independent notion of cut-off events, used to truncate a Petri net unfolding. Such a notion is based on a cutting context and results in the unique canonical prefix of the unfolding. Canonical prefixes are complete in the new, stronger sense, and we provide necessary and sufficient conditions for its finiteness, as well as upper bounds on its size in certain cases. A surprising result is that after suitable generalization, the standard unfolding algorithm presented in [8], and the parallel unfolding algorithm proposed in [12], despite being non-deterministic, generate the canonical prefix. This gives an alternative correctness proof for the former algorithm, and a new (much simpler) proof for the latter one.Received: 29 April 2003, Published online: 2 September 2003 相似文献
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Petri net is a powerful tool for system analysis and design. Several techniques have been developed for the analysis of Petri nets, such as reachability trees, matrix equations and reachability graphs. This article presents a novel approach to constructing a reachability graph, and discusses the application of the reachability graph to Petri nets analysis. 相似文献
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A generalized fuzzy Petri net model 总被引:14,自引:0,他引:14
The paper proposes a new model of Petri nets based on the use of logic based neurons. In contrast to the existing generalizations, this approach is aimed at neural-type modeling of the entire concept with a full exploitation of the learning capabilities of the processing units being used there. The places and transitions of the net are represented by OR and AND-type and DOMINANCE neurons, respectively. A correspondence between this model and the previous two-valued counterpart is also revealed. The learning aspects associated with the nets are investigated 相似文献
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面向对象Petri网建模技术综述 总被引:1,自引:0,他引:1
阐述了面向对象技术和Petri网的结合方式,提出了面向对象Petri网的建模过程,给出其详细的建模步骤和流程图,讨论了面向对象Petri网的动态特性分析方法,分析和总结了OOPN,OOCPN、OOAPN以及OOTPN的研究现状和各自建模的利弊,最后对面向对象Petri网的相关技术和发展趋势进行了综述与展望. 相似文献