基于语义的Web服务发现核心技术研究

在研究Web服务本体描述语言OWL S缺乏对服务质量的明确刻画的基础上,引入服务质量本体QoSOn对OWL S规范进行扩展。其次,提出了“两阶段”匹配模型,该算法首先经过基于服务分类的匹配剔除不相关的服务,然后引入服务相似度来度量候选广告服务和请求服务之间的相似程度;候选服务和请求服务之间的相似度是通过OWL S Profile的功能相似度和QoSOn本体的服务质量相似度两个方面进行综合评估的。最后,通过对比实验证明了该匹配算法的可行性和有效性。     

Wukong: A cloud-oriented file service for mobile Internet devices

Along with the rapid growth of heterogeneous cloud services and network technologies, an increasing number of mobile devices use cloud storage services to enlarge their capacity and share data in our daily lives. We commonly use cloud service client-side software in a straightforward fashion. However, when more devices and users participate in heterogeneous services, the difficulty of managing these services efficiently and conveniently increases. In this paper, we report a novel cloud-oriented file service, Wukong, which provides a user-friendly and highly available facilitative data access method for mobile devices in cloud settings. Wukong supports mobile applications, which may access local files only, transparently accessing cloud services with a relatively high performance. To the best of our knowledge, Wukong is the first file service that supports heterogeneous cloud services for mobile devices by using the innovative storage abstraction layer. We have implemented a prototype with several plugins and evaluated it in a systematic way. We find that this easily operable file service has a high usability and extensibility. It costs about 50 to 150 lines of code to implement a new backend service support plugin. Wukong achieves an acceptable throughput of 179.11 kB/s in an ADSL environment and 80.68 kB/s under a countryside EVDO 3G network with negligible overhead.     

基于WSMO服务质量的语义Web服务发现框架

当前对Web服务进行语义描述最流行的两个框架是OWL-S和WSMO,但它们主要都是从服务功能的角度对服务进行描述,缺乏对服务质量的明确刻画,导致服务请求者难以得到最佳服务.针对此问题,对WSMO规范进行了扩展,定义了一个服务质量(QoS)的元模型--WSMO-QoS,给出了QoS的本体词汇.在此基础上提出了基于QoS的语义Web服务发现框架,并给出一个从基本描述、IOPE、QoS三个层次实现服务匹配的算法.最后,实验结果验证了该服务匹配算法的有效性.     

WSB: a broker‐centric framework for quality‐driven web service discovery

Web service interfaces can be discovered through several means, including service registries, search engines, service portals, and peer‐to‐peer networks. But discovering Web services in such heterogeneous environments is becoming a challenging task and raises several concerns, such as performance, reliability, and robustness. In this paper, we introduce the Web Service Broker (WSB) framework that provides a universal access point for discovering Web services. WSB uses a crawler to collect the plurality of Web services disseminated throughout the Web, continuously monitor the behavior of Web services in delivering the expected functionality, and enable clients to articulate service queries tailored to their needs. The framework features ranking algorithms we have developed which are capable of ranking services according to Quality of Web Service parameters. WSB can be seamlessly integrated into the existing service‐oriented architectures. Copyright © 2010 John Wiley & Sons, Ltd.     

Contextual patterns in mobile service usage

Mobile services differ from other services because of their temporal and spatial attributes. Mobile services additionally differ from each other in their value-added to the end-user. Some services—such as emailing and voice—are more business oriented. On the other hand, various free-time oriented services are provided in new smartphones, such as imaging and music playback. The present paper studies how mobile services are used in different contexts. For this, the paper develops a specialized algorithm that can be used with handset-based usage data acquired straight from end-users in an established panel study process. Educated guesses can be drawn on the user context based on the developed algorithm. In the present exercise usage contexts were divided into home, office and “on the move”. The algorithm is used with exemplary data from Finland and the UK covering 324 consumers in 2006. More than 70% of contextual use cases are correctly classified based on raw data. According to exemplary results particularly multimedia services are used “on the move”, whereas legacy mobile services experience more evenly distributed usage across all contexts. The algorithm that identifies context based on raw data provides a new angle to mobile end-user research. In the future, the accuracy of the algorithm will be improved with the integration of seamless cell-id logging and GPS data.     

基于历史用户QoS感知的Web服务发现方法

目前的Web服务发现方法,由于没有充分利用用户情境信息,导致在服务发现时间和结果准确率方面存在不足。首先对包括当前用户在内的情境相似的用户进行了聚类,缩小了服务发现的范围;然后,在此基础上利用当前用户偏好信息及情境相似的历史用户感知到的候选服务的QoS数据,给出了一种基于历史用户QoS感知的Web服务发现方法,包括候选服务的QoS数据获取和综合权重计算;最后,结合实验并与其他Web服务发现方法进行比较,证明了该方法在服务发现结果的准确率和时间效率方面均有了一定的提升。     

基于QoS的语义Web服务发现研究

将QoS引入到语义Web服务中,分析了QoS本体的描述方法、Web服务的发现方法和语义Web服务发现方法,建立了一个通用的QoS模型,模型中的参数属性基本能描述QoS的衡量标准。提出了基于QoS语义Web服务发现框架,第一步通过功能来发现Web服务,第二步通过建立的QoS模型来评价发现的Web服务集合,找到QoS最佳的Web服务。最后通过实例建立了语义功能本体和QoS本体。     

语义Web和Web服务标准集成的研究

首先提出基于本体的增强Web服务描述能力的方法,即将语义添加到Web服务的标准WSDL和UDDI中。然后,提出一种基于语义的Web服务发现算法。基于语义的Web服务发现过程比原有的基于服务属性的服务发现过程更为准确和有效。     

A semantic service discovery approach for ubiquitous computing

Services in the ubiquitous computing are heterogeneous in nature. To be pervasive, these services should be defined in terms of their functionality and capabilities rather than the meaningless Universally Unique IDentifiers (UUIDs) or types of services. With that, clients can access the proper service based on semantic requests, rather then a pre-configured profile. In this paper, we study the requirements for semantic query to be feasible in service discovery processes. Current discovery protocols and the concept of semantics are brought together to construct a framework to realize the semantic service discovery for ubiquitous computing. Many issues are discussed in relation to service discovery topologies, ontology languages, and semantic query languages.     

基于多本体的语义Web服务发现研究

随着大量Web服务的出现,迫切需要高效的服务发现方法。语义Web服务将Web服务和语义相结合,充分利用语义增强Web服务。现有的语义Web服务发现研究中,大多采用同一本体描述服务需求方和提供方的知识。而现实世界里,很多时候服务需求方和服务提供方采用了不同的本体。针对多本体下的语义Web服务发现问题,给出了一种新的计算不同本体概念相似性的算法,提出了基于多本体的语义Web服务发现方法。实验结果表明了该方法的有效性。     

一种分布式Web服务发现方法

Web服务发现系统由一个或多个服务注册器连接组成一定的系统拓扑来存储和维护服务信息,服务注册器的连接拓扑直接关系到Web服务发现系统的可扩展性。采用层次模型在数据层定义统一的动态元组模型来解决各种数据源和数据模型的异构性,在抽象层定制统一的发布和查询API实现统一的访问方式,在网络层构造一种全新的双层结构保证整个系统的可扩展性、灵活性和鲁棒性,设计实现了一种分布式Web服务发现方法。给出了适应双层拓扑结构的两阶段查找算法,并对算法的时间、空间和消息复杂性进行了分析。实验结果表明,该Web服务发现方法具有明显的自组织特性和良好的可扩展性,适应Web服务自主,动态变化和强分布特点,同时两阶段查找算法具有较好的服务查找能力。     

S-Club: an overlay-based efficient service discovery mechanism in CROWN Grid

Information service plays a key role in grid system, handles resource discovery and management process. Employing existing information service architectures suffers from poor scalability, long search response time, and large traffic overhead. In this paper, we propose a service club mechanism, called S-Club, for efficient service discovery. In S-Club, an overlay based on existing Grid Information Service (GIS) mesh network of CROWN is built, so that GISs are organized as service clubs. Each club serves for a certain type of service while each GIS may join one or more clubs. S-Club is adopted in our CROWN Grid and the performance of S-Club is evaluated by comprehensive simulations. The results show that S-Club scheme significantly improves search performance and outperforms existing approaches. Chunming Hu is a research staff in the Institute of Advanced Computing Technology at the School of Computer Science and Engineering, Beihang University, Beijing, China. He received his B.E. and M.E. in Department of Computer Science and Engineering in Beihang University. He received the Ph.D. degree in School of Computer Science and Engineering of Beihang University, Beijing, China, 2005. His research interests include peer-to-peer and grid computing; distributed systems and software architectures. Yanmin Zhu is a Ph.D. candidate in the Department of Computer Science, Hong Kong University of Science and Technology. He received his B.S. degree in computer science from Xi’an Jiaotong University, Xi’an, China, in 2002. His research interests include grid computing, peer-to-peer networking, pervasive computing and sensor networks. He is a member of the IEEE and the IEEE Computer Society. Jinpeng Huai is a Professor and Vice President of Beihang University. He serves on the Steering Committee for Advanced Computing Technology Subject, the National High-Tech Program (863) as Chief Scientist. He is a member of the Consulting Committee of the Central Government’s Information Office, and Chairman of the Expert Committee in both the National e-Government Engineering Taskforce and the National e-Government Standard office. Dr. Huai and his colleagues are leading the key projects in e-Science of the National Science Foundation of China (NSFC) and Sino-UK. He has authored over 100 papers. His research interests include middleware, peer-to-peer (P2P), grid computing, trustworthiness and security. Yunhao Liu received his B.S. degree in Automation Department from Tsinghua University, China, in 1995, and an M.A. degree in Beijing Foreign Studies University, China, in 1997, and an M.S. and a Ph.D. degree in computer science and engineering at Michigan State University in 2003 and 2004, respectively. He is now an assistant professor in the Department of Computer Science and Engineering at Hong Kong University of Science and Technology. His research interests include peer-to-peer computing, pervasive computing, distributed systems, network security, grid computing, and high-speed networking. He is a senior member of the IEEE Computer Society. Lionel M. Ni is chair professor and head of the Computer Science and Engineering Department at Hong Kong University of Science and Technology. Lionel M. Ni received the Ph.D. degree in electrical and computer engineering from Purdue University, West Lafayette, Indiana, in 1980. He was a professor of computer science and engineering at Michigan State University from 1981 to 2003, where he received the Distinguished Faculty Award in 1994. His research interests include parallel architectures, distributed systems, high-speed networks, and pervasive computing. A fellow of the IEEE and the IEEE Computer Society, he has chaired many professional conferences and has received a number of awards for authoring outstanding papers.     

A location model for smart environments

This paper presents a location model for location-aware and user-aware services in smart environments. It can be dynamically organized like a tree based on geographical containment, such as that in a user–room–floor–building hierarchy and each node in the tree can be constructed as an executable software component. The model is unique in existing approaches because it enables location-aware services to be managed without any database servers, it can be managed by multiple computers, and it can provide a unified view of the locations of not only physical entities and spaces, including users and objects, but also computing devices and services. A prototype implementation of this approach was constructed on a Java-based mobile agent system. This paper presents the rationale, design, implementation, and applications of the prototype system.     

基于语义规则的Web服务发现方法

语义Web服务发现问题研究的核心内容是服务描述与对应的服务发现方法。服务描述分为服务请求描述与服务发布描述,但目前的服务发现方法,并未将请求描述与发布描述分开,以比对服务请求描述与服务发布描述中对应部分作为匹配依据,导致服务请求描述构建困难以及发现结果不够理想。提出以语义规则刻画服务请求描述,以本体构建服务发布描述,进行有效的以语义规则驱动的Web服务发现。对语义规则添加影响因子使得服务匹配精度可以通过匹配度来度量,并按照给定的调节系数来决定最终匹配是否成功。最后以OWL-S TC V2测试服务集合进行了对比实验,证实该方法有效地提高了查全率与查准率高,特别是Top-k查准率。     

基于本体的Web服务发现算法研究

随着Web服务数目的增长,基于关键字的发现机制已不能满足Web服务的需要。引入领域本体概念,提出一种基于领域本体的Web服务发现匹配算法WSDA。该算法采用Web服务本体描述语言（OWL-S）描述Web服务,采用改进的基于几何距离的语义匹配方法,将概念关系图映射到数据库中,方便了Web服务间相似度的计算和比较。通过实验验证算法的可行性和有效性。     

Service discovery in mobile ad hoc networks: A field theoretic approach

Service discovery in mobile ad hoc networks is challenging because of the absence of any central intelligence in the network. Traditional solutions as used in the Internet are hence not well suited for mobile ad hoc networks. In this paper, we present a novel decentralized service discovery mechanism for ad hoc networks. The basic idea is to distribute information about available services to the network neighborhood. We achieve this by using the analogy of an electrostatic field: A service is modelled by a (positive) point charge, and service request packets are seen as (negative) test charges which are attracted by the service instances. In our approach, we map the physical model to a mobile ad hoc network in a way where each network element calculates a potential value and routes service requests towards the neighbor with the highest potential, hence towards a service instance. Our approach allows for differentiation of service instances based on their capacity. We define the required protocols and methods which we implemented in a network simulator. Using extensive simulations, we evaluate the performance and robustness of the mechanisms. The results indicate good performance and convergence even in highly mobile environments. We believe that this technique can and should be further exploited, e.g., as a routing protocol in mobile ad hoc networks.     

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。