一种基于Petri网的网络服务兼容性分析方法

针对目前基于网络服务业务过程执行语言(BPEL)的网络服务合成方法缺乏网络服务的兼容性分析机制,不能保证基于网络服务技术的业务过程正确执行的问题,建立了一种能从形式化的角度描述网络服务的接口交互情况的基于Petri网的多元工作流组合网模型,提出了一种能更快地获得网络服务可用性结果的网络服务兼容性判断算法.最后,提出了基于该算法的原型系统架构.     

基于广义随机Petri网GSPN的系统安全性研究

针对基于广义随机Petri网GSPN的动态系统安全性建模与分析方法进行了系统研究。基于Petri网、GSPN模型的基本原理，提出了关键状态搜索算法，并进行了安全性仿真分析．将广义随机Petri网的扩展模型应用于安全性分析领域，丰富了动态系统安全性问题的研究手段。     

基于Petri网的包装物流系统建模仿真与优化

采用离散事件动态系统理论和Petri网建模技术,研究包装物流系统建模、仿真与优化,描述和分析系统要素及逻辑序列.以纸箱包装物流系统为例进行建模、仿真,优化分析,获得了该系统的优化模型.结果表明,这种研究方法可行有效.     

高级Petri网及FMS的动态建模和仿真

给出了一种柔性制造系统模型，它能模仿和跟踪车间中散件调度计划的执行过程。模型由一类新的高级Ｐｅｔｒｉ网组成，它定义了着色令牌，时化变迁和谓词变迁，抽象了物理对象的主要属性和它们间的基本关联。通过数据库描述令牌属性，规则库描述变迁，构成了一种结构紧凑，信息丰富，可反映多个工作进程的高级Ｐｅｔｒｉ网模型。     

基于完成端口的网络服务应用程序开发

由于互联网的普及,在线人数也越来越多,这就提高对服务器端应用程序性能的要求。因此,讲述windows平台上高性能网络服务应用程序的开发方法。     

基于IPRAN承载网的LTE基站部署优化方法

结合LTE技术的特点,对基于IPRAN承载网的LTE基站部署优化方法进行了分析和探讨,希望可以为LTE业务的部署提供相应的参考依据。     

一种实现无扰切换的功能块系统及其着色Petri网建模

提出了基于着色Petri网（CP网）的功能块集成模型。这模型采用模块化、面向对象的建模思想,分别以一个CP网来描述不同的功能块,在每个CP网内部定义了内部变量和外部消息。当利用功能构造控制系统时,相应地把代表它们的CP网集成在一起,并且通过消息传递,协调功能块之间的作用关系,共同完成控制系统的功能。     

FMS统一建模技术与方法

针对ＦＭＳ的组成结构及控制特点，提出了一种层次递阶的统一建模方法。以面向对象建模技术和方法为主线，通过消息传递驱动机制使各层递阶模型有机集成为统一的整体，并与实际系统中各个层次及其关系相对应，从而准确，方便地描术字ＦＭＳ的规划设计、调度控制、运行及仿真等各个过程。     

Windows XP支持的网络服务研究

微软公司发布的一款视窗操作系统Windows XP提供很多功能。主要研究Windows XP提供的常用网络服务功能。     

浅谈网络服务的安全性与开放性

网络服务作为Internet的上层建筑,提供给用户多样的服务。本文对网络服务的驱动力及存在基础、网络服务的创建、网络服务的性能安全、网络服务的开放性等进行了介绍分析。     

A model based approach to assess the performance of production systems in degraded mode

Nowadays production systems are asked to perform their activities in a high uncertainty environment and to guarantee their performance in this environment. Therefore, they are asked to master risks that are part of their daily activities, to maintain the performance which is considered as their key success factor. Risks may cause serious effects that threaten the production systems and degrade their performance. Nevertheless, we cannot estimate the degradation that a risk may cause to system performance, since risk analysis methods found in the literature do not allow simulating the behaviour of the system in degraded mode. In order to help production systems to assess their performance in risk situations, we propose in this paper a model-based approach that enables assessing the performance of production systems in degraded mode. Our approach is based on function, interaction, structure (FIS) modelling framework that enables modelling complex system and its failures. The resulting model is converted into an executable simulation model based on a new class of Petri Nets (PNs) called predicate-transition, prioritised, synchronous (PTPS) PN. The obtained simulation model is then executed in order to obtain performance indicators in degraded mode. This tool is used during the system design, in order to study the impact of risks on the designed production system performance. It is also used to study an existing production system in order to analyse and optimise its behaviour in degraded mode. In this article, we present our tool and apply it to a special case of production systems which is a hospital sterilisation system.     

一种提供用户偏好选择的Web服务组合方法

分析了用户对于组合的Web服务的一些软性的偏好,对这些偏好的表达和基于这些偏好的Web服务组合进行了研究,提出了一种提供用户偏好选择的Web服务组合方法.该方法利用模糊约束来表达用户的偏好,将用户的偏好和满意程度转化成为模糊约束满足问题,进而使用分支定界法对层次化任务网络(HTN)进行分解.实验结果表明,用户的满意程度有显著的提高.     

A combined approach to solve the redundancy optimization problem for multi-state systems under repair policies

This paper combines universal moment generating function technique with stochastic Petri nets to solve the redundancy optimization problem for multi-state systems under repair policies. Redundant elements are included in order to achieve a desirable level of production availability. The elements of the system are characterized by their cost, performance and availability. These elements are chosen from a list of products available on the market. The number of repair teams is less than the number of reparable elements, and a repair policy specifies the maintenance priorities between the system elements. A heuristic is proposed to determine the minimal cost system configuration under availability constraints. This heuristic, first applies universal moment generating function technique to evaluate the system availability, assuming unlimited maintenance resources. Once a preliminary solution is found by the optimization algorithm, stochastic Petri nets are used to model different repair policies, and to find the best system configuration (architecture and number of repairmen) in terms of global performance (availability and cost). This combined procedure is applied to a reference example.     

基于动态描述逻辑的Web自动化服务组合

研究了动态描述逻辑(DDL)在Web服务组合中的应用。基于目标规划以及动态描述逻辑给出了Web服务组合算法。该算法考虑了客户的个人偏好,扩大了Web服务的应用范围。它使用DDL进行Web服务组合刻画,因为DDL将具有相似功能的服务划为一个动作集合,因而能够实现对语义Web中的动态知识和静态知识的统一描述,克服描述逻辑缺乏对动态知识描述的不足。该算法能够利用目标规划给出主体的动作执行序列,以有效实现Web服务的自动组合。最后通过具体实例验证了该算法的可行性。     

A network approach to parametric design integration

This article presents a method for the integration of multiple computing processes used in design and design assessment for a parametric design problem. The method is based on a representation in which the processes are regarded as performing transformations between model states representing attributes of the designed artefact. A classification of attributes and of transformations is presented. The sequences of transformations and model states are modelled using Petri nets, and these models are used as a basis for the development of a computer-based controller that manages the interprocess interaction. The controller directs the concurrent and sequential operation of a number of computing processes operating on different workstations in a network. These processes include geometric modelling and a variety of design analysis actions that exchange data with each other in the optimum design of parametric parts. The example of an automotive crankshaft design is given.     

Web services in the retail industry

It is a well-known fact that the retail industry always works on razorthin margins and the key to survival lies in optimization of resources both in space and time dimensions as well as maximization of customer satisfaction. Access to timely and even real-time information to a wide variety of channel and trading partners, sales personnel, line managers, store managers etc. is the key to achieving this. Web services technology holds out a lot of promise for the retail industry in this respect. It is a platform-neutral, easy to deploy set of standards for achieving business data and process integration, without going for proprietary point to point connections. It promises to connect the information providers and information consumers across a wide variety of platforms, devices and on an on-demand basis. Being based on service-oriented architecture (SOA) principles it can also form the enabling service interface layer for other emerging technologies like BAM, BPM, mobile and RFID. In this paper, we attempt to understand information-flow needs in the retail industry and also suggest a roadmap approach by which the retail enterprise could exploit the potential of web services at minimal risk.     

广域网分布式爬虫中的Agent协同与Web划分研究

针对广域网环境下分布式Web爬虫的Agent协同和Web划分两个核心问题进行深入研究,提出了基于顾问服务的分布式Web爬虫系统模型,给出了详细的系统设计方案及Agent协同算法框架,并通过推导证明了顾问服务参与Agent协同能够使分布式爬虫系统承受相对较小的网络负载。提出了分布式Web爬虫Web划分的概念,围绕Web划分单元选取及Web划分策略,对Web划分的分类和实现进行了详细的讨论,并通过实验对多种Web划分方法进行了对比和评价,验证了广域网系统相对于局域网系统的优势,并发现运营商互连因素对爬虫系统性能的影响大于地理位置因素的影响。     

基于阶层式语义范例推理的服务组合方法研究

为了解决自动服务组合过程中的知识表示和知识积累问题和提高服务组合的可重用性、准确性并减少服务组合的代价,提出了一种基于阶层式语义范例推理的自动服务组合方法。该方法先通过设计适当的语义服务范例描述语言来描述不同类型的服务范例,然后构造阶层式的服务范例,在此基础上通过服务范例的相似度测量与选择机制获取满足用户需求的组合服务逻辑集成或引用,实现服务组合。通过与其他服务组合方法的对比实验与定性分析证明,基于语义范例推理的服务组合方法是可行和有效的。     

A coloured Petri net-based hybrid heuristic search approach to simultaneous scheduling of machines and automated guided vehicles

To achieve a significant improvement in the overall performance of a flexible manufacturing system, the scheduling process must consider the interdependencies that exist between the machining and transport systems. However, most works have addressed the scheduling problem as two independent decision making problems, assuming sufficient capacity in the transport system. In this paper, we study the simultaneous scheduling (SS) problem of machines and automated guided vehicles using a timed coloured Petri net (TCPN) approach under two performance objectives; makespan and exit time of the last job. The modelling approach allows the evaluation of all the feasible vehicle assignments as opposed to the traditional dispatching rules and demonstrates the benefits of vehicle-controlled assignments over machine-controlled for certain production scenarios. In contrast with the hierarchical decomposition technique of existing approaches, TCPN is capable of describing the dynamics and evaluating the performance of the SS problem in a single model. Based on TCPN modelling, SS is performed using a hybrid heuristic search algorithm to find optimal or near-optimal schedules by searching through the reachability graph of the TCPN with heuristic functions. Large-sized instances are solved in relatively short computation times, which were a priori unsolvable with conventional search algorithms. The algorithm’s performance is evaluated on a benchmark of 82 test problems. Experimental results indicate that the proposed algorithm performs better than the conventional ones and compares favourably with other approaches.