语义Web在Web服务中的应用

在分析了现有的Web服务标准和语义Web的基础上，介绍了一种把二者结合起来的语义Web服务（SwS）。它可以实现在不需要人的参与下，Web服务的自动发现、自动调用和自动组合。对于语义Web服务的开发有3种方法，文中重点介绍了实现SWS的一种基于本体的面向代理的OWL—S开发方法。     

自动组合服务框架的研究和设计

自动的服务组合指的是自动化整个工作流构造过程.它包括自动的服务发现和服务选择,保证语义和数据类型的一致性.在分析现今一些框架的功能和不足的基础上,提出了一种在SOA(Service-oriented Architecture)架构下使用语义Web技术的自动服务组合框架.该框架的主要目标就是支持基于语义描述的Web服务的发现、选择和组合.     

基于情景演算的Web服务语义描述

Web服务是WWW发展的一个重要的趋势,Web服务的相关问题得到了广泛的研究和应用,Web服务的自动组合是其中一个热点。要实现Web服务的自动组合,必须对Web服务的语义进行形式化的描述。情景演算是一种形式化的建模和规划方法,利用情景演算对Web服务进行描述,能使自动组合结果更加快速和准确。在分析情景演算特点的基础上,使用情景演算对一个基于Web服务的会议行程安排系统进行了Web服务语义描述。     

整合Agent与语义Web服务

目前的语义web服务方法和标准提供了很多由Agent平台操纵的基础设施,这有利于Agent与语义web服务的结合。本文分析了语义web服务与Agent之间的关系,提出Agent的主要角色是用来封装用户的意图,协调用户的目标,并最终调用web服务.我们利用当前的Agent技术与语义web服务技术,设计出自己的平台,整合了Agent BDI模型与语义Web服务。     

一种P2P环境中基于语义的Web服务组合方法

Web服务组合研究是Web服务领域一个研究热点。本文利用0WL-S语言对Web服务进行描述,提高Web服务的机器可理解性,并利用语义信息进行Web服务组合操作。文中提出一个在JXTA环境中实现Web服务组合的模型,在其上实现了一个基于语义的Web服务组合方法,并通过一个简单的实例说明语义Web服务组合的具体过程。     

基于Agent技术的语义Web服务发现研究

随着Web服务量的急剧增长,传统的基于UDDI的服务发现机制已经很难满足用户的需求,其根本原因是其缺乏语义信息.为了提高Web服务发现的质量,提出了一种基于Agent技术的语义Web服务发现模型(ASWS matchmaker),该模型对所搜索内容进行语义描述并通过Agent对Web服务进行智能搜索,从而发现用户感兴趣的服务.最后,给出了该模型用于Web服务的一个实例,实例表明该模型不仅提高了Web服务发现的准确率,还能够更好地满足用户的个性化需求.     

基于领域本体和OWL-S的Web服务组合方法

针对Web服务普遍存在服务描述的语义异构问题,提出基于领域本体和OWL-S的语义Web服务组合方法。该方法采用本体概念实现Web服务的语义标注,在OWL-S语言基础上,通过定制组合过程,实现语义Web服务的组合。实例采用Protégé及OWL-S Editor工具,结果证明领域本体和OWL-S能够实现优势互补。     

基于图规划的语义Web服务自动组合方法

由于单个的Web服务功能有限,难以满足日益增长和不断变化的用户需求.如何根据服务请求者的特定需求进行服务的自动组合来满足用户的需要,就成为了一个迫切需要解决的问题.提出了一种基于图规划的语义Web服务自动组合方法,该方法在建立前驱与后继执行关系知识库的基础上,利用图规划的前向扩张思想和图规划解搜索思想,可实现从服务库中自动地找到满足用户需求的服务组合方案.该方法综合考虑了服务语义和服务组合的效率等因素,在保证Web服务组合质量的前提下,可根据服务请求实现服务的自动组合.最后用仿真实验从服务组合的成功率、效率和组合解质量三方面验证了该方法的有效性和可行性.     

基于Agent的语义web服务发现模型研究

Web服务发现是Web服务系统架构的重要部分,现有的主流Web服务发现方法采用基于UDDI框架的服务匹配。针对现有服务发现模型缺乏对语义信息的支持和发现精确程度不高的问题,本文在讨论Agent技术与语义Web服务技术的基础上,提出了一个基于Agent的语义Web服务发现模型,使服务发现的过程更加智能,也提高了服务发现的精确度,并设计了一个原型系统来验证所提出的服务发现方法的可行性。     

P2P环境下基于语义的Web服务组合研究

利用OWL-S语言描述Web服务,在组合操作中加入语义信息,实现了Web服务组合的自动化。为了提高Web服务的搜索速度,采用Chord路由算法。构建了一个P2P环境下基于Chord网络的Web服务组合模型,在其上实现了基于语义的Web服务组合,最后通过实例给出了语义Web服务自动组合过程。     

METEOR-S WSDI: A Scalable P2P Infrastructure of Registries for Semantic Publication and Discovery of Web Services

Web services are the new paradigm for distributed computing. They have much to offer towards interoperability of applications and integration of large scale distributed systems. To make Web services accessible to users, service providers use Web service registries to publish them. Current infrastructure of registries requires replication of all Web service publications in all Universal Business Registries. Large growth in number of Web services as well as the growth in the number of registries would make this replication impractical. In addition, the current Web service discovery mechanism is inefficient, as it does not support discovery based on the capabilities of the services, leading to a lot of irrelevant matches. Semantic discovery or matching of services is a promising approach to address this challenge. In this paper, we present a scalable, high performance environment for Web service publication and discovery among multiple registries. This work uses an ontology-based approach to organize registries into domains, enabling domain based classification of all Web services. Each of these registries supports semantic publication and discovery of Web services. We believe that the semantic approach suggested in this paper will significantly improve Web service publication and discovery involving a large number of registries. This paper describes the implementation and architecture of the METEOR-S Web Service Discovery Infrastructure, which leverages peer-to-peer computing as a scalable solution.     

基于语义的QoS感知Web服务发现机制

随着提供相同功能的Web服务数量的日益增多,服务质量(Quality of Service,QoS)成为用户选择Web服务的重要考虑因素.目前,通过对服务QoS属性在语法层匹配来提供Web服务选取的机制不能很好地满足复杂QoS属性匹配的要求.研究了基于用户QoS需求偏好,将用户需求的QoS与候选服务的QoS进行语义比较,结合约束规划(Constraint Programming)方法,在语义层匹配Web服务的QoS属性,选取满足匹配要求的服务,最后对满足QoS属性值约束的候选服务进行优化选择处理,获取最终匹配的候选服务.     

Putting Web Services in Context

When considering the full range of Web service-related activities, it becomes clear that dealing with context is a major challenge, requiring greater expressiveness, reasoning capabilities, and architectural components than are provided by the current widely accepted building blocks of the Web services stack. This paper presents an informal overview of concepts, requirements and challenges for handling contextual knowledge in connection with Web services, and briefly discusses several interesting projects in this area of research.     

Agent技术在Web服务中的应用探讨

Web服务是一组采用面向服务的体系架构的基于标准的Web协议的软件构件,而Agent是一种在某个环境中自主行动以实现其设计目标的智能化软件实体.Web服务与多Agent系统(MAS,Multi-Agent System)在架构、范例和技术方法等方面具有很大的相似性.Web服务的可信性是未来计算机软件发展关键的问题,实现Web服务在分布式环境下的协同式测试具有一定的挑战性.本文在探讨Web服务与Agent技术的共性的基础上,分析并总结了Agent技术在Web服务中的应用.针对Web服务测试的开放性、协同性、动态性和不确定性等特点,结合Agent系统的自主性、反应性、适应性和社会性,本文提出了一种基于MAS的Web服务测试框架(MAST,Multi-Agent-based Service Testing),并对其关键技术进行了探讨.     

Learning domain ontologies for semantic Web service descriptions

High quality domain ontologies are essential for successful employment of semantic Web services. However, their acquisition is difficult and costly, thus hampering the development of this field. In this paper we report on the first stage of research that aims to develop (semi-)automatic ontology learning tools in the context of Web services that can support domain experts in the ontology building task. The goal of this first stage was to get a better understanding of the problem at hand and to determine which techniques might be feasible to use. To this end, we developed a framework for (semi-)automatic ontology learning from textual sources attached to Web services. The framework exploits the fact that these sources are expressed in a specific sublanguage, making them amenable to automatic analysis. We implement two methods in this framework, which differ in the complexity of the employed linguistic analysis. We evaluate the methods in two different domains, verifying the quality of the extracted ontologies against high quality hand-built ontologies of these domains.

Our evaluation lead to a set of valuable conclusions on which further work can be based. First, it appears that our method, while tailored for the Web services context, might be applicable across different domains. Second, we concluded that deeper linguistic analysis is likely to lead to better results. Finally, the evaluation metrics indicate that good results can be achieved using only relatively simple, off the shelf techniques. Indeed, the novelty of our work is not in the used natural language processing methods but rather in the way they are put together in a generic framework specialized for the context of Web services.     

IRS-III: A broker-based approach to semantic Web services

A factor limiting the take up of Web services is that all tasks associated with the creation of an application, for example, finding, composing, and resolving mismatches between Web services have to be carried out by a software developer. Semantic Web services is a combination of semantic Web and Web service technologies that promise to alleviate these problems. In this paper we describe IRS-III, a framework for creating and executing semantic Web services, which takes a semantic broker-based approach to mediating between service requesters and service providers. We describe the overall approach and the components of IRS-III from an ontological and architectural viewpoint. We then illustrate our approach through an application in the eGovernment domain.     

数据汇聚与发布服务在水环境实时监控系统中的应用

以“苏州市古城区水环境实时监控系统”为背景,基于智能Agent和Web服务的思想,提出了一类数据汇聚与发布服务的模型并予以实现。数据汇聚子模块收集来自不同单位、不同地点、不同监测仪及采用不同测试方法所得到的数据,主要解决数据格式不一致及同一监测项多数据源的融合等问题;数据发布子模块为不同权限的用户提供不同程度、不同形式的数据共享。所实现的数据汇聚与发布服务具有良好的可扩展性和互操作性,适用于大规模的水环境分布式应用。