Web Services合成方案向BPEL4WS的自动转换

合成方案自动转换为BPEL4WS模块是Web Services实时动态语义合成系统SASO的核心组成部分。该文使用DAG作为Web Services合成方案的表示方法;在此基础上提出了WTOP自动转换算法,通过运行时代码动态生成的方法,实现从DAG到BPEL4WS的自动转换。     

QoS驱动的Web Services方案相关合成

现有的Web Services合成算法较少关注Services的多标准,且较少考虑方案相关的思想.即使有算法考虑到上述问题,但为了体现方案相关,把全部的方案进行穷举后再进行对比,因此工作量繁杂.将QoS方法引入Web Services合成,对方法进行改进,从而在QoS的计算中体现方案相关.通过向量表示Services的代价,然后相应地改进迪捷斯特拉算法,逐步更新代价向量并计算QoS值进行路径选择.实验证明,该算法能在较好的时间复杂度内得到用户满意的合成方案, 在用户给定输出数量较大时,优势更为明显.     

Web Services动态合成技术的研究

为了提高Web Services合成的效率,减少用户查询时过多的人工干预,提出了一个Web Services最佳路径动态合成框架.在该框架下以产生式的形式建模,构建一个适合于最佳路径算法的DAG图,以参数级本体解决合成过程中的语义冲突问题,并通过最佳路径算法进行合成.通过分析比较,该框架特别适合于对同样的用户输入和Web Services进行多次合成以生成相同的或者不同的输出,同时也避免了回溯和对合成方案的优化.     

Web Services集成技术

本文首先介绍了Web Services的基本概念和应用背景,在此基础上分析当前使用的Web Services合成的意义。然后阐述基本的Web Services合成方式及其介绍在Web服务中消除语义的方法,重点研究了动态服务合成过程和语义分析方法,最后对于Web Services的集成应用进行了展望。     

基于目标距离评估的启发式Web Services组合算法

随着可用Web Services数量的快速增长,如何根据用户的需求来自动组合Web Services,生成满足用户需求的组合业务,成为一项亟待解决的课题.提出了一种基于用户需求目标距离评估的启发式算法,通过该算法,动态调用Web Services来自动生成满足用户所需目标的Web Service组合,同时,该算法还能够根据Web Services组合经验,对以后的Web Services组合方案进行调整.实验结果表明:该算法能够很好地适应网络上Web Services的不稳定情况,与同类算法进行性能比较,也显示出基于目标距离评估的算法具有较好的性能.     

Web Services安全性方案及实现

该文主要探讨了Web Services的安全性问题以及解决方案。简要介绍了Web Services安全技术,提出了实现Web Services安全性的具体实现方案:包括利用用户名/密码来设定访问权限;对客户端IP地址进行过滤;以及使用加密数据传输方式来实现Web Services的安全。     

一种有QoS保障的Web服务组合方法

随着可用Web Services数量的快速增长，如何根据用户的需求来自动组合Web Services，生成满足用户需求的组合业务，成为一项亟待解决的课题。提出了一种基于QoS的启发式算法，通过该算法，动态调用Web Services来自动生成满足用户所需目标的Web Service组合．同时，该算法还能够根据Web Services组合经验，对以后的Web Services组合方案进行调整。实验结果表明：该算法能够很好地适应网络上Web Services的不确定情况，与同类算法进行性能比较，也显示出较好的性能。     

在Web Services动态合成中的最佳路径算法

为实现Web Services动态、自动的合成,以减少合成过程中过多的人工干预,提出了一个基于A*算法的最佳路径算法.该算法通过对核心的估值函数的设计,启发式地对Web Services进行选择合成,从而能够将最适当的服务配置到合成的结果当中去.分析比较结果表明,该算法能够合成出最适当的服务并且服务合成的时耗较少.     

动态Web Services的约束满足优化技术研究

Web Services合成是Web Services技术的重要方面,能够按要求提供选择新的服务。本文首先提出了Web Services服务约束的分类描述,进而分析了Web Services服务合成中如何按照服务约束指导服务选择,进而选择合适的服务集来满足客户的要求。该方法把动态Web Services合成转化为约束满足问题。     

基于Web Services技术的电子商务集成研究

针对当前电子商务发展的现状,探讨了如何将Web Services技术应用于电子商务中。Web Services是一种面向服务的体系结构。具有松散耦合、互操作性、普遍性、易于使用和行业支持等特点。文中基于Web Services的特点,在现有网络资源的基础上．提出了一个基于Web Services的电子商务集成方案。     

Quality-of-service oriented web service composition algorithm and planning architecture

In the next few decades, it is expected that web services will proliferate, many web services will offer the same services, and the clients will demand more value added and informative services rather than those offered by single, isolated web services. As the result, the problem of synthesizing web services of high quality will be raised as a prominent issue. The clients will face the trouble of choosing or creating composition plans, among numerous possible plans, that satisfy their quality-of-service (QoS) requirements. Typical QoS properties associated with a web service are the execution cost and time, availability, successful execution rate, reputation, and usage frequency. In engineering perspective, generating the composition plan that fulfills a client’s QoS requirement is a time-consuming optimization problem. To resolve the problem in a timely manner, we propose a constraint satisfaction based web service composition algorithm that combines tabu search and simulated annealing meta-heuristics. As an implementation framework of the algorithm, we suggest a QoS-oriented web service composition planning architecture. The architecture maintains expert made composition schemas in a service category and assists the client as pure user to choose the one he/she wants to use. The main modules of the architecture are composition broker and execution plan optimizer. With the aid of the UDDI server, the composition broker discovers candidate outsourced web services for each atomic process of the selected schema and gathers QoS information on the web services. After that, the execution plan optimizer runs the web service composition algorithm in order to generate a QoS-oriented composition plan. The performance of the algorithm was tested in a simulated environment.     

A monolithic approach to automated composition of semantic web services with the Event Calculus

In this paper, a web service composition and execution framework is presented for semantically -annotated web services. A monolithic approach to automated web service composition and execution problem is chosen, which provides some benefits by separating composition and execution phases. An AI planning method using a logical formalism, namely Abductive Event Calculus, is chosen for the composition phase. This formalism allows one to generate a narrative of actions and temporal orderings using abductive planning techniques given a goal. The functional properties of services, namely input/output/precondition/effects (IOPE) are taken into consideration in the composition phase and non-functional properties, namely Quality of Service (QoS) parameters are used in selecting the most appropriate solution to be executed. The repository of OWL-S semantic web services are translated to the Event Calculus axioms and the resulting plans found by the Abductive Event Calculus Planner are converted to graphs. These graphs can be sorted according to a score calculated using the defined quality of service parameters of the atomic services in the composition to determine the optimal solution. The selected graph is converted to an OWL-S file which is executed consequently.     

一种基于CBR和多Agent的Web服务个性化组合

客户的满意度是衡量Web服务组合的重要指标之一。为解决Web服务组合中客户满意度的缺失问题,提出一种基于CBR(Case-based Reasoning)和多Agent的个性化的Web服务组合算法。在给出Web服务客户满意度属性的定义基础之上,建立了属性偏好的权重向量求解模型,并通过多目标规划寻找服务组合的最优解,从而实现了Web服务组合的个性化。原型系统表明了其可行性。     

基于有限状态自动机的Web服务组合

Web服务是Web上的特殊软件资源,可以被应用系统发现和调用.如何根据用户的需求(目标服务)来组合Web服务是研究中需要解决的重要问题.通过使用有限状态自动机,服务组成的社区中的状态和操作可以使用有限状态自动机来模拟,这样可以表示服务操作的内部和外部概要.结合确定性动态命题逻辑,可以根据已有的Web服务,解决目标服务的可组合问题,产生组合计划.同时讨论了算法的复杂性.     

Service Composition and Execution Plan Generation of Composite Semantic WEB Services Using Abductive Event Calculus

Web Service composition is indispensable, as a single web service cannot satisfy the complex functional requirement of a user. The two key challenges of semantic web service composition are the discovery of the most relevant atomic services from the composite semantic web services and by no means we can assure the execution of the composed atomic services in a proper order. In this work, these two challenges are addressed, and a novel architecture is proposed for atomic service discovery, composition and automatic plan generation for the proper execution of its candidate services. The proposed architecture takes the advantage of abductive event calculus that uses abductive theorem prover to generate a plan for the proper order of execution of the atomic services. The research has found that the plan generated by the proposed architecture is sound and complete.     

基于扩展语义接口的Web服务动态组合方法

自动地根据用户请求进行服务的动态组合是目前Web服务领域的关键问题.针对该问题,提出了一种基于本体的服 务动态组合方法,设计并实现了一个服务动态组合原型.首先Web服务按照一定规则被抽象为本体模型,然后通过分析所 构造服务的模型来实现服务的匹配,最后利用BPEL4ws对匹配生成的服务组合序列来进行自动的组合.实验结果表明,该 方法细化了服务接口的语义,并且在发现结果上有更高的准确性.     

Hybrid Metaheuristics Web Service Composition Model for QoS Aware Services

Recent advancements in cloud computing (CC) technologies signified that several distinct web services are presently developed and exist at the cloud data centre. Currently, web service composition gains maximum attention among researchers due to its significance in real-time applications. Quality of Service (QoS) aware service composition concerned regarding the election of candidate services with the maximization of the whole QoS. But these models have failed to handle the uncertainties of QoS. The resulting QoS of composite service identified by the clients become unstable and subject to risks of failing composition by end-users. On the other hand, trip planning is an essential technique in supporting digital map services. It aims to determine a set of location based services (LBS) which cover all client intended activities quantified in the query. But the available web service composition solutions do not consider the complicated spatio-temporal features. For resolving this issue, this study develops a new hybridization of the firefly optimization algorithm with fuzzy logic based web service composition model (F3L-WSCM) in a cloud environment for location awareness. The presented F3L-WSCM model involves a discovery module which enables the client to provide a query related to trip planning such as flight booking, hotels, car rentals, etc. At the next stage, the firefly algorithm is applied to generate composition plans to minimize the number of composition plans. Followed by, the fuzzy subtractive clustering (FSC) will select the best composition plan from the available composite plans. Besides, the presented F3L-WSCM model involves four input QoS parameters namely service cost, service availability, service response time, and user rating. An extensive experimental analysis takes place on CloudSim tool and exhibit the superior performance of the presented F3L-WSCM model in terms of accuracy, execution time, and efficiency.     

基于QoS多目标优化的Web服务组合方法

为了确保在服务组合中获得Pareto最优解集,把服务组合建模为多个服务质量属性同时优化的多目标优化问题,提出了一种依据服务质量属性类型的通用预处理方法,采用多个信息素表和单个启发式信息表的多目标蚁群算法,蚂蚁随机选择一种信息素表建构可行解,每个蚁群周期完成后所有信息素都会蒸发,但每个优化函数只有一个最优解获得信息素增加,经过多过蚁群周期后即可解获得最优解集.实验结果表明,该方法可为Web服务组合提供一种很好的优化方案,具有很高的准确率.     

基于服务组合的GIS应用模型集成方法研究

针对当前GIS应用模型集成过程中存在的数据和功能冗余、模型难以复用等问题,指出基于Web服务组合技术在GIS应用模型集成中的优势,提出了一种GIS应用模型驱动的服务组合方法,并详细阐述了模型分解、服务组合流程、服务选取及实现技术等,为扩展GIS的应用功能提供了一种可行的解决方案。最后,以震害应急指挥过程为例表明了该方法能有效提高模型集成的灵活性和复用性,有较高的应用价值。