共查询到20条相似文献,搜索用时 250 毫秒
1.
扩展有限递归进程模型上海交通大学自控系黄典伟,吴智铭主要讨论离散事件动态系统的建模问题。由K.Inan和P.Varaiya提出的有限递归进程(FRP)是描述并发离散事件动态系统的有力工具,但该FRP中没有定义对数据变量的操作和条件转移算子。本文将FR... 相似文献
2.
SDL语言动态语义模型的研究 总被引:1,自引:0,他引:1
介绍了SDL系统规范,基于通信扩展有限状态机CEFSM的SDL进程。系统最重要的属性是行为,动态语义模型用元进程描述系统可观察的行为。研究了ITUZ.100建议附件F中元进程的划分,提出一种新的元进程定义,并举例描述了SDL系统的动态语义模型。 相似文献
3.
混合动态系统起因于离散事件系统用于监控连续状态系统的行。本文用抽象语言方法描述连续状态系统,研究状态离散事件系统描述的一致性。基于输入输出观点简要地 讨论了离散控制器综合。 相似文献
4.
5.
6.
本文讨论无环向图和皮特利网描述的一类离散事件动态系统的特征值的求解方法,对事件延迟系统,给出了频域的特征矩阵M(z)的特征值求法,并由之提出一个新的求取闭环无环向图描述的离散系统特征值的方法。 相似文献
7.
8.
9.
离散时间Petri网是一种系统模拟和分析的有效工具,它可以结合图形和分析描述评估离散事件系统的动态执行.基于T—S模糊模型,提出用于描述离散时间Petri网的模糊模型,讨论该模型适应于TtPNs的情况,用以推广文章结论,并且给出用于TtPNs的线性模糊控制规则.同时,文章还给出TtPNs聚合的结论. 相似文献
10.
一、引言许多排队系统和生产系统可以看作是离散事件系统。它们的特点是系统的动态变化过程是用事件或活动来描述的,事件的变化仅在离散而且是随机的时刻发生。这一类系统有别于连续采样时间系统,通常称为离散事件动态系统(Discrete Event Dynamic Systems)。这类系统传统的分析方法是以随机服务理论为基础的。实际上,对一个复杂的离散事件系统很少用解析方法进行分析,主要困难在于很难甚至根本无法得到系统的解析解,而且还要求实 相似文献
11.
Real-time discrete event systems are discrete event systems with timing constraints, and can be modeled by timed automata.
The latter are convenient for modeling real-time discrete event systems. However, due to their infinite state space, timed
automata are not suitable for studying real-time discrete event systems. On the other hand, finite state automata, as the
name suggests, are convenient for modeling and studying non-real time discrete event systems. To take into account the advantages
of finite state automata, an approach for studying real-time discrete event systems is to transform, by abstraction, the timed
automata modeling them into finite state automata which describe the same behaviors. Then, studies are performed on the finite
state automata model by adapting methods designed for non real-time discrete event systems. In this paper, we present a method
for transforming timed automata into special finite state automata called Set-Exp automata. The method, called SetExp, models the passing of time as real events in two types: Set events which correspond to resets with programming of clocks, and Exp events which correspond to the expiration of clocks. These events allow to express the timing constraints as events order
constraints. SetExp limits the state space explosion problem in comparison to other transformation methods of timed automata, notably when the
magnitude of the constants used to express the timing constraints are high. Moreover, SetExp is suitable, for example, in supervisory control and conformance testing of real-time discrete event systems. 相似文献
12.
《Simulation Practice and Theory》1998,6(4):413-422
This paper is aiming at discussing modeling problems of hybrid event dynamic systems, which consist of continuous, discrete and inference-decision event dynamic systems. The event is the fundamental element of all kinds of event dynamic systems mentioned above. The very important meaning of the hybrid event dynamic system is that the large scale, complex and especially comprehensive systems could be abstracted as a hybrid event dynamic system, whose concept and theory are convenient for studying and analyzing them. Therefore, this paper discusses the problems about event, continuous, discrete, inference-decision and hybrid event dynamic systems and its modeling. 相似文献
13.
We introduce a new architecture for the design of a tool for modeling and simulation of continuous and hybrid systems. The environment includes a compiler based on Modelica, a modular and a causal standard specification language for physical systems modeling (the tool supports models composed using certain component classes defined in the Modelica Standard Library, and the instantiation, parameterization and connection of these MSL components are described using a subset of Modelica). Models are defined in Modelica and are translated into DEVS models. DEVS theory (originally defined for modeling and simulation of discrete event systems) was extended in order to permit defining these of models. The different steps in the compiling process are show, including how to model these dynamic systems under the discrete event abstraction, including examples of model simulation with their execution results. 相似文献
14.
Masked prioritized synchronization for interaction and control of discrete event systems 总被引:1,自引:0,他引:1
Extends the formalism of prioritized synchronous composition (PSC), proposed by Heymann for modeling interaction (and control) of discrete event systems, to permit system interaction with their environment via interface masks. This leads to the notion of masked prioritized synchronous composition (MPSC), which we formally define, MPSC can be used to model interaction of systems at single as well as multiple interfaces. We show that MPSC can alternatively be computed by "unmasking" the PSC of "masked" systems, thereby establishing a link between MPSC and PSC. We next prove that MPSC is associative and thus suitable for modeling and analysis of supervisory control of discrete event systems. Finally, we use MPSC of a discrete event plant and a supervisor for controlling the plant behavior and show (constructively) that under the absence of "driven" events, controllability together with normality of the given specification serve as conditions for the existence of a supervisor. This extends the results on supervisory control, which permits control and observation masks to be associated with the plant only. 相似文献
15.
Due to its ability to support temporal issues of systems, discrete event simulation is widely applicable to real-time system
design. This paper presents a methodology for the modeling and simulation of time-constrained message routing policies for
hypercube interconnected real-time systems. The methodology is based on a framework called the DEVS (discrete event systems
specification) formalism which supports modular and hierarchical specification of discrete event models. Within the methodology,
we first develop DEVS specification for models for hypercube computers and experimental frames to measure the performance
of alternative message routing policies. We then implement such specification in DEVSIM++, a C++-based modeling/simulation
environment that implements the DEVS formalism. Simulations of various message routing policies are performed, and the performances
of such policies are compared. 相似文献
16.
研究了网络遥操作系统的半张量积建模问题.网络遥操作系统中存在人机交互以及大时延事件,这使得系统中既有离散事件动态又有连续动态,当系统的离散事件动态与底层连续动态相互作用耦合强烈时,系统的性能、行为分析变得更为复杂.本文通过引入半张量积给出了一种新的半张量积混杂建模方法,它把一类特定事件系统建模为布尔系统,通过半张量积方法得到类似于离散动态系统的方程.它将系统中离散事件和连续动态相互耦合的地方表达为半张量积的形式,最后经过扩张简化得到完整统一的系统数学模型,它将有利于进一步分析、计算.本文给出的半张量积建模方法和步骤具有一定的通用性和一般性.此外本文还对基于半张量积的混杂网络遥操作系统模型进行了基于事件控制和时间控制的仿真.仿真结果表明,半张量积建模方法完全可信、可行,基于事件控制的方法在网络遥操作控制中明显优于基于时间控制的方法. 相似文献
17.
18.
Ahmet Zengin Author Vitae 《Information Sciences》2011,181(5):1028-1043
Scalability in simulation tools is one of the most important traits to measure performance of software. The reason is that today’s Internet is the main instance of a large-scale and highly complex system. Simulation of Internet-scale network systems has to be supported by any simulation tool. Despite this fact, many network simulators lacks support for building large models. In this work, in order to propose a new approach for scalability issue in network simulation tools, a network simulator is developed based on behavior of honeybees and high performance DEVS, modular and hierarchical system theoretic approach. A biologically-inspired discrete event modeling approach is described for studying networks’ scalability and performance traits. Since natural systems can offer important concepts for modeling network systems, key adaptive and emergent attributes of honeybees and their societal properties are incorporated into a set of simulation models that are developed using the discrete event system specification approach. Large-scale network models are simulated and evaluated to show the benefits of nature-inspired network models. 相似文献
19.
This paper introduces condition/event (C/E) systems as a class of continuous-time discrete event dynamic systems (DEDS) with two types of discrete-valued input and output signals:condition signals andevent signals. In applications such as discrete control, C/E systems provide an intuitive continuous-time modeling framework amenable to block diagram representation. In this paper we consider C/E systems with discrete state realizations, and study the relationship between continuous-time C/E systems and untimed models of their sequential inputoutput behavior called C/E languages. We show that C/E systems with discrete state realizations are necessarilytime-change invariant (Theorem 3.1), which means the ensemble of admissible continuous-time input-output behaviors is completely characterized by the C/E language for the system (Theorem 4.1). It is also shown that deterministic C/E systems with discrete state realizations are necessarily discrete-time (clocked) systems (Corollary 3.1), and that finite discrete state realizations exist for a C/E system only if its related C/E language has a finite state generator (Theorem 4.2). Finally, we develop equivalent discrete-state realizations for C/E systems resulting from cascade and feedback interconnections. The paper concludes with a discussion of several directions for future research.Please direct correspondence concerning this paper to B.H. Krogh at the above address. 相似文献
20.
Ptolemy是一个广泛应用于信息物理融合系统的建模和仿真工具包,主要通过仿真的方式保证所建模型的正确性.形式化方法是保证系统正确性的重要方法之一.本文提出了一种基于形式模型转换的方法来验证离散事件模型的正确性.离散事件模型根据不同事件的时间戳触发组件,时间自动机模型能够表达这个特征,因此选用Uppaal作为验证工具.首先定义了离散事件模型的形式语义,其次设计了一组从离散事件模型到时间自动机的映射规则.然后在Ptolemy环境中实现了一个插件,可以自动将离散事件模型转换为时间自动机模型,并通过调用Uppaal验证内核完成验证.最后以一个交通信号灯控制系统为例进行了成功的转换和验证,实验结果证实了该方法能够验证Ptolemy离散事件模型的正确性. 相似文献