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1.
为了描述图标间的相互作用和它们的动态行为,作者提出了一个基于Perti网的图标编程系统。本文讨论了组成该系统各成分的功能,并设计了网络分析的生成算法。通过实例说明了系统工作过程和Petri网理论在可视化程序设计中的重要作用。  相似文献   

2.
为了描述图标间的相互作用和它们的动态行为,作者提出了一个基于Petri网的图标编程系统.本文讨论了组成该系统各成分的功能,并设计了网络分析图的生成算法.通过实例说明了系统工作过程和Petri网理论在可视化程序设计中的重要作用.  相似文献   

3.
Authorware是一种基于设计图标和流程线为结构的编程平台,它具有很好的可视化交互编程环境,由于它支持WIN-DOWS的ActiveX标准,具有动态链接功能,所以具有相当强大的多媒体创作功能。本文结合开发AutoCAD多媒体学习软件的体会,向大家介绍几个实用技巧。1利用文件属性的设置,制作直接在光盘上运行的多媒体程序。在Authorware中,可以用声音图标(SOUNDICON)、数字电影图标(Distalmovie)等引入外部的声音文件(WAV等)或数字电影文件(*陀G等),一旦5;入之后,AUm-orware会记录该9即文件的存储位置,程序运行时,将…  相似文献   

4.
夏榆滨  龚良波 《微计算机信息》2007,23(28):247-248,260
针对现有的构件模型的公共行为与业务行为的交织的问题,结合面向方面编程(AOP)的动态织入的动态代理技术,构造一种基于动态代理构件模型。该构件模型明确区分并定义了各种构件,并应用动态代理技术解耦了各类构件之间的相互调用,提高了系统的可维护性和扩展性。  相似文献   

5.
一、引言在当今的软件开发中,可视化的和基于软件构件的编程环境已经得到广泛的应用。在这里软件构件(SoftwareComponent)是指具有如下特征的软件对象:1.该对象具有一定的属性,可以在运行和设计时进行编辑;2该对象具有一定的方法,该对象具有的功能可以通过调用其方法得到实现;3.该对象会产生一定的事件,从而引发对事件的相应处理;4.该对象是可以二进制重用的;典型的软件构件是大家熟悉的JavaBean和ActiveX构件。由于大部分软件构件提供用于编辑其属性的GUI界面,故此很多的可视化编程环境都支持对软构件的使用。典型的环…  相似文献   

6.
CAR技术是面向构件的编程模型和编程规范。目前,现有的各种IDE工具并未对其提供开发支持,这就需要一个专门的构件开发平台。文章详细阐述了一个运行于Eclipse平台之上,基于这个通用平台架构的CAR构件的开发平台,重点介绍了这个平台的结构与特点。该平台具有很强的灵活性、可定制性与扩展性,可为基于CAR构件的动态编程提供支持。  相似文献   

7.
韩浩  茅兵  谢立 《计算机工程》2012,38(4):122-125
根据面向返回的编程(ROP)攻击及其变种的攻击原理,设计一个针对ROP攻击的动态运行时检测系统。该系统包括静态插桩和动态运行监控2个阶段。静态插桩为待检测程序装配分析代码,动态运行利用ret完整性检测、call完整性检测和jmp完整性检测方法分析程序的控制流和数据流,判断是否为ROP攻击。实验结果表明,该方法能完全检测出ROP恶意代码。  相似文献   

8.
面向方面编程与构件技术的结合是开发更加可复用、可扩展的软件的新方法,不同于传统的通过修改系统架构以及引入新的编程语言实现二者的结合。提出一种将文件划分为构件与方面,利用XML语言描述构件与方面的编织关系,结合构件客器技术与面向方面编程的方法实现构件与方面的运行时编织的方法。新的方法既可以简单方便地描述方面,又有效地扩展了现有系统,原有构件不需要任何改动,就可以直接实现同方面的编织,井确保比较高的运行效率。同时该方法在CAR上的软件工程实践也作了描述。  相似文献   

9.
针对7×24小时运行的系统,不能停止系统运行进行更新或维护的问题,根据OSGi( Open Service Gateway Initiative)框架的特点,在分析已有的服务动态更新方法基础上,克服已有策略不能保证服务更新前后的相互一致性和服务状态的一致性,以及更新策略实现过程中的编程模型不佳问题,提出基于发布/订阅模型的服务动态更新策略.以静止状态理论为依据,利用Petri网形式化描述服务动态更新过程,从理论上验证该策略的有效性;同时,以Event Admin Service作为策略的实现工具,具有良好的编程模型,从而实现OSGi平台上的动态演化,实验结果表明该策略具有可行性.  相似文献   

10.
无级电话网动态路由策略的研究   总被引:1,自引:0,他引:1  
无级电话网的动态路由技术能有效降低呼损、提高接通率。本文针对所开发的一个集中式、全局优化无级电话网动态路由策略选择系统进行综述;详细分析了求解路由方案的四种算法;介绍了该系统的实现、运行情况和话务模拟结果;该系统在广东省长话网得到了良好的应用。  相似文献   

11.
A framework for icon management which is quite object-oriented is proposed, and an iconic programming system named HI-VISUAL is presented on the basis of the framework. In the framework, icons represent real objects or concepts already established in a target application environment, whereas icons representing functions are not provided. A function is represented by a combination of two different icons. Each icon can take an active or a passive role against the other. The role sharing is determined dynamically, depending on the environment in which the icons are activated. Programming in HI-VISUAL and implementation issues of the system prototype, now in operation in a laboratory environment, are extensively discussed  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.
The formal semantics of a prototyping language for hard real-time systems, PSDL, is given. PSDL provides a data flow notation augmented by application-orientation timing and control constraints to describe a system as a hierarchy of networks of processing units communicating via data streams. The semantics of PSDL are defined in terms of algebraic high-level Petri nets. This formalism combines algebraic specifications of abstract data types with process and concurrency concepts of Petri nets. Its data abstraction facilities are used to define the meaning of PSDL data types, while high-level Petri nets serve to model the casual and timing behavior of a system. The net model exposes potential concurrency of computation and makes all synchronization needs implied by timing and control constraints explicit and precise. Time is treated as state of clocks, and clocks are modeled as ordinary system components. The net semantics provides the basis for applying analysis techniques and semantic tools available for high-level Petri nets  相似文献   

14.
C4ISR系统是一个规模庞大、层次分明的离散动态系统。文章提出了一种面向C4ISR系统的UML和Petri网结合的建模分析方法。该方法采用从上到下的层次分析方法。用扩展的UML模型对系统组织结构和系统的静态特征进行描述,用扩展的Petri网模型描述和分析系统动态特性,通过相应的规则将Petri网模型转化成状态图和序列图。新方法可以对系统要求进行验证,同时还可以编程实现。最后通过该方法,对一个C4ISR系统进行了建模分析。  相似文献   

15.
Accurate and timely information sharing among multiple participants is one of the crucial factors for collaboration in crisis management. The icon-based map was frequently applied as an effective means for crisis interaction and collaboration. However, former studies only regarded the icons as supplementary visualization components during the whole crisis collaboration process. In this paper, the concept of a structured-icon-relied interactive method was proposed to directly integrate all kinds of crisis and coordination information through icons on the crisis map. Moreover, structured icons are supposed to explicitly show the correlation among crisis information and to improve the interactive experience of information search. The effectiveness of this interactive method was verified by a controlled experiment with three sub-tasks for simulated crisis rescue. The results of the experiment showed that the design of the crisis map based on structured icons had a positive impact on collaborative decision-making and crisis interaction. The dynamic characteristics of the structured icon could represent the temporal and spatial attributes of crisis information and enhance users’ crisis coordination ability. The study aims to enrich the theory of crisis information visualization and interaction based on structured iconic representation. In practice, this research could optimize the design of a crisis collaboration system based on the icon as well as the interaction between people, crisis information, and collaborative system, which in turn provides accurate and timely rescue decisions.  相似文献   

16.
Petri网是一种具有动态特性的建模工具,模糊Petri网是Petri网的一个重要分支,可以有效处理具有不精确的、不确定的复杂因素的系统模型问题。本文在模糊动态Petri网的定义和运行规则基础上,研究了具有死锁和陷阱结构的模糊Petri网系统,通过配置不同的初始标识,分析其动态运行特性,并给出算例分析。  相似文献   

17.
徐淑琳  周广瑞  岳昊 《计算机工程》2021,47(4):285-290,297
为获得制造系统初始化时的最小资源以实现最优资源分配,利用标注Petri网对系统进行建模,并研究标注Petri网的最小初始标识估计问题。给定一个标注Petri网,在不可观测变迁组成无环子网的情况下,基于动态规划提出一种新的最小初始标识估计算法。在观察到给定的标注序列后,放宽不可观测变迁发生个数的限制,并根据该算法构建节点的演化过程。当出现相同的发生数向量时,仅保留当前极小的初始标识估计,并通过节点的演化过程对极小初始标识估计的托肯总数进行对比。为验证算法的有效性,给出一个制造系统的标注Petri网模型实例,最终得到的最小初始标识为[1000]T,且对应的变迁发生序列为t1t3t4t6,满足给定标注Petri网的结构要求。实验结果表明,与传统基于动态规划的算法相比,该算法获得的最小初始标识估计具有更小的托肯总数。  相似文献   

18.
基于Petri网的工作流模型   总被引:7,自引:4,他引:7  
Petri网是一种很有效的模型描述语言,不仅能描述系统的结构特性,同时还能描述其动态特性,尤其适用于描述含有并行成分的系统,而工作流技术作为实现企业过程集成的有效手段,广泛用于各种场合。在简要介绍了Petri网和工作流基本知识的基础上,指出了基于Petri网的工作流模型的优点,讨论了将工作流模型转化为Petri网模型的基本原则,并且提出了一种扩展的Petri网模型作为一种工作流建模的工具,最后对基于Petri网的工作流模型进行了总结。  相似文献   

19.
Identification of Petri Nets from Knowledge of Their Language   总被引:1,自引:0,他引:1  
In this paper we deal with the problem of identifying a Petri net system, given a finite language generated by it. First we consider the problem of identifying a free labeled Petri net system, i.e., all transition labels are distinct. The set of transitions and the number of places is assumed to be known, while the net structure and the initial marking are computed solving an integer programming problem. Then we extend this approach in several ways introducing additional information about the model (structural constraints, conservative components, stationary sequences) or about its initial marking. We also treat the problem of synthesizing a bounded net system starting from an automaton that generates its language. Finally, we show how the approach can also be generalized to the case of labeled Petri nets, where two or more transitions may share the same label. In particular, in this case we impose that the resulting net system is deterministic. In both cases the identification problem can still be solved via an integer programming problem.
Carla SeatzuEmail:
  相似文献   

20.
We report on an iconic interface that implements a restricted subset of SQL commands for querying a database. Database queries and the query language's tokens (verbs, adjectives, etc.) are represented by icons. To construct a query, the user composes structured iconic expressions according to the grammar of the iconic language. The language and grammar include rules for iconic construction (Quadral Composite Icons and Serial Composite Icons). In brief, the user visually queries the database by issuing structured iconic queries composed in a systematic manner. The paper describes the syntactic and semantic principles behind structured iconic expressions and the way that these principles have been implemented in an iconic interface. User evaluation is informally reported, and the role of metaphor in the design and interpretation of icons is discussed.  相似文献   

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