一类混杂系统的广义Petri网模型

提出一种含有变形连续时不变系统状态方程的广义Ｐｅｔｒｉ网，并用它为一类混杂系统建模：宏观为Ｐｅｔｒｉ网；微观为变形的线性时不变状态方程．同时研究了所提出的混合状态的演变规则、运行轨迹和状态方程．     

一类混杂系统的建模与分析

提出一种广义Ｐｅｔｒｉ网，改进原有线性连续时不变ＳＩＳＯ系统的状态方程，并用它为一类混杂系统建模。同时提出一种混合状态，研究了该状态的演变规则、运行轨迹和状态方程。     

针对一般线性约束的Petri网控制器设计方法

针对基于Petri网离散事件系统关于标识向量和Parikh向量的不等式约束反馈控制器设计问题,提出一种新的控制器设计方法.该方法首先利用Petri网的状态方程把关于标识向量和Parikh向量的不等式约束转变成关于Parikh向量的不等式约束,然后基于Petri网库所是关于Parikh向量的不等式约束的观点构造控制器.最后将该方法与Iordache和Moody提出的方法作比较,实验结果显示该方法更简单、有效.     

基于改进的网重写系统途径的可重构制造单元故障恢复

提出了一种用于可重构制造单元故障恢复的策略与方法, 允许故障发生时, 通过对用于正常操作控制的Petri网形式的监督控制器进行局部、临时性的修改, 实现故障的恢复. 首先, 提出改进的网重写系统, 可用于动态改变Petri网模型结构. 然后,提出了基于改进的网重写系统的故障恢复方法, 其中改进的网重写系统用于操作、引导Petri网监督控制器由错误状态进入正确状态. 故障恢复后监督控制器的结构与期望属性维持不变. 最后, 以实例演示了该故障恢复方法的应用, 证实了方法的有效性.     

基于约束优化的Petri网可达性分析

Petri网的可达性判定问题是进行Petri网分析的基础。通过分析目前求解Petri网可达问题的判定方法和基于约束程序的Petri网可达问题判定方法,提出一种基于约束优化的Petri网可达问题判定方法,该方法是在状态方程法的基础上,利用约束程序寻求可行解,再利用优化求最优解,从而减少问题搜索的分支,达到减少状态方程的解空间的目的。最后通过实例的求解验证算法能够提高判定效率。     

一种面向故障诊断的模糊Petri网

运用Petri网进行故障诊断推理时,常存在一种故障对应着多种原因的可能,推理结论不能区分并列原因间的相对可能性,且不能体现人工经验.针对这一问题,定义了一种面向故障诊断的模糊Petri网,运用基于状态方程的推理方法,将人工经验用模糊值表示并参与推理运算,以相应库所对应的模糊信息值来衡量库所对应事件的可信度,从而可以实现区分并列事件间的相对可能性.通过某控制系统故障诊断实例,验证了所定义的模糊Petri网和状态方程及其诊断算法的正确性和有效性.     

报文审批系统的赋时着色PN建模

报文审批系统(RAS)是一种典型的离散事件动态系统,适合用Petri网技术对其进行分析.考虑到传统Petri网具有一些固有的缺陷,文中基于高级Petri网--赋时着色Petri网(TCP-Net)理论,对RAS进行了分析,构造了RAS的赋时着色Petri网模型,给出了颜色转移函数.并且为了使用户能直观地了解当前报文的审批情况,还给出了流程跟踪算法.最终结果可以看出与传统Petri网模型相比,TCP-Net模型的复杂度已大大降低,并且结构简单清晰.     

基于扩展Petri网的文本分类模型

在扩展Petri网基础上提出了一种新的文本分类模型。基本思想是利用定性映射方法扩展Petri网系统,利用状态方程进行推理,使文本分类更接近于人类思维判断过程,并给出了分类算法。     

基于精炼操作的Petri网建模及其分析方法

针对复杂系统的Petri网建模及其分析问题,定义了Petri网的精炼操作及其相关的Petri网模型.基于序列投影,建立精炼Petri网与原网、子网间的动态行为关联关系,并分析了该精炼操作的相关动态性质,得到一组性质保持判据.最后,基于该方法实现了一个顺序资源共享系统的应用案例的建模及其分析.所提出的方法不仅为复杂系统的Petri建模提供了新的思路,而且有助于复杂Petri网模型的分析和验证.     

离散制造装配系统的活性控制

首次研究离散制造装配系统的活性控制问题.建立了系统的工件加工过程Petri网 模型.通过对系统Petri网模型的结构分析,提出了导致系统死锁的两类元素结构及活性特 征.对一类离散制造装配系统提出了避免死锁的Petri网控制器,这类控制器容易实现,对系 统的限制小,而且使得受控系统仍具Petri网模型.对一般离散制造装配系统提出了保证系统 活性的控制策略.     

A synthesis technique of general petri nets

The general Petri net (GPN) is useful for modeling flexible manufacturing systems with multiple robots and workstations [15] and for parallel programs [8]. A problem of using reachability analysis for analyzing Petri nets (PN) is the large number of states generated. Most of the existing synthesis techniques do not deal with GPN. Koh et al.[15] invented a synthesis technique for GPN. We propose to improve their achievement by adding the simple Arc-ratio rules to Yaw's knitting technique [37, 38, 39] based on the notion of structure relationship together with new path generations, which mark the most distinct feature compared with other approaches. The synthesis rules and procedures of how to update the temporal matrix and structure synchronic distance are presented. The Arc-ratio rules for GPN are also presented. One can successfully synthesize complicated Petri nets using these rules. An example to synthesize a Petri net in [15] is illustrated. The correctness of each synthesis rule with an appropriate Arc-ratio rule for GPN is proved.     

Cross-paradigm analysis of autonomous agent architecture

Autonomous agent architectures are design methodologies—collections of knowledge and strategies which are applied to the problem of creating situated intelligence. This article attempts to integrate this knowledge across several architectural traditions, paying particular attention to features which have tended to be selected under the pressure of extensive use in real-world systems. We determine that the following strategies provide significant assistance in the design of autonomous intelligent agents: (i) modularity, which simplifies both design and control; (ii) hierarchically organized action selection, which focusses attention and provides prioritization when different modules conflict; and (iii) parallel environment monitoring which allows a system to be responsive and opportunistic by allowing attention to shift and priorities to be re-evaluated. We offer a review of four architectural paradigms: behaviour-based AI; two- and three-layered systems; belief, desire and intention architectures (particularly PRS); and Soar/ACT-R. By documenting trends within each of these communities towards establishing the components above, we argue that this convergent evolution is strong evidence for the components' utility. We then use this information to recommend specific strategies for researchers working under each paradigm to further exploit the knowledge and experience of the field as a whole.     

Fractals and Quasi-Affine Transformations

In the continuum , contracting affine transformations have a unique fixed point. It is well known that this property is not preserved by dicretization and that the dynamics of discretized functions are very complicated. Discrete geometry allows us to start a theory for these dynamics and to illustrate some of their features by pictures. These pictures, rendered by a simple algorithm, reveal a very large spectrum of fractal structures, from the simplest to the intricatest.     

实时离散事件系统的动态反馈控制

本文研究了一类含确定性状态时间的实时离散事件系统的动态反馈控制问题.基于一定 语言的实时可控性的概念,证明了对给定实时离散事件系统G,存在完备监控器φ使L(φ/ Gr)=K的充分必要条件是K是闭及实时可控的,并得到了有关实时监控问题解存在的充要 条件.     

基于GPN径向基神经网络的边缘检测方法

在基于神经网络的边缘检测模型中,大部分模型的检测效率不高,检测效果也有待提升.本文受人眼视觉系统特性的启发,提出了一种新的基于GPN （Gaussian Positive-Negative）径向基神经网络的边缘检测方法.首先,本文构造了一种新型的基于GPN径向基神经网络,将图像中经高斯滤波预处理后的每个像素点作为GPN径向基神经网络的中心点,并将其输入神经网络;然后,在每层之间使用卷积神经网络的部分特性进行处理,经过扩展层和隐层计算后输出结果;最后根据输出结果利用轮廓跟踪的方法将边缘提取出来.本文在检测效果以及效率这2个方面进行了相应的数值实验.针对合成图像以及部分灰度不均匀图像,相较于脉冲耦合神经网络模型、遗传神经网络模型以及卷积神经网络模型,本文模型在效率上得到了提升,且边缘的连通性更好.实验结果表明,本文提出的基于GPN径向基神经网络的边缘检测方法是一种新的、有效的边缘检测方法,比传统的神经网络边缘检测方法效率更高,且在检测效果上也有所提升.     

Reference ontologies to support the development of global production network systems

In competitive and time sensitive market places, organisations are tasked with providing product lifecycle management (PLM) approaches to achieve and maintain competitive advantage, react to change and understand the balance of possible options when making decisions on complex multi-faceted problems, global production networks (GPN) is one such domain in which this applies. When designing and configuring GPN to develop, manufacture and deliver product–service provision, information requirements that affect decision making become more complex. The application of reference ontologies to a domain and its related information requirements can enhance and accelerate the development of new product-service systems with a view towards the seamless interchange of information or interoperability between systems and domains.This paper presents (i) preliminary results for the capture and modelling of end-user information, (ii) an initial higher level reference core ontology for the development of reference ontologies and (iii) the formal logical modelling of Level 1 of the FLEXINET reference ontology using a Common Logic based approach.     

Learning the demand function in a repeated Cournot oligopoly game

In this article, single product Cournot oligopolies are considered, where the demand and cost functions are linear. While cost functions are completely known by all firms, they only partially know the demand function, as they misspecify the slope. At any stage of the repeated oligopoly game firms update the slope of their subjective demand functions on the basis of the discrepancy they observe between the expected price, computed according to believed demand, and the price they actually observe. This adjustment process has a unique steady state, where any subjective demand function coincides with the true demand function. If such steady state is stable, then the true slope of the demand function can be learned by all oligopolists, even if they start from misspecified initial guesses. Sufficient conditions for the stability of the steady state are given for n-firms oligopolies. In the particular case of a duopoly, an exact delimitation of the stability region in the parameters’ space is given, and with the help of numerical simulations, the size and the shape of the basins of attraction is analysed, as well as the kinds of attracting sets that characterise the long-run dynamics of the learning process when the steady state is unstable.     

On the existence of periodic solutions in time-invariant fractional order systems

Periodic solutions and their existence are one of the most important subjects in dynamical systems. Fractional order systems like integer ones are no exception to this rule. Tavazoei and Haeri (2009) have shown that a time-invariant fractional order system does not have any periodic solution. In this article, this claim has been investigated and it is shown that although in any finite interval of time the solutions do not show any periodic behavior, when the steady state responses of fractional order systems are considered, periodic orbits can be detected.     

A generalized prime-number-based matrix strategy for efficient iconic indexing of symbolic pictures

In this paper, we propose an efficient iconic indexing strategy called generalized prime-number-based matrix (GPN Matrix) for symbolic pictures, in which each spatial relationship between any two objects is represented as a product of some prime numbers from a set of 12 prime numbers and is recorded in a matrix. In the proposed strategy, we classify 169 spatial relationships between two objects in 2D space into five spatial categories, and define a generalized category rule (based on module operations) for each of those five spatial categories. As compared to the prime-number-based matrix (PN Matrix) strategy (Chang and Yang, 1997), in which each spatial relationship between any two objects is represented as a product of some prime numbers from a set of 17 prime numbers, the GPN Matrix strategy has a smaller storage space requirement than the PN Matrix strategy, which also improves the query processing time.