An automatic subdigraph renovation plan for failure recovery of composite semantic Web services

A Web service-based system never fulfills a user’s goal unless a failure recovery approach exists. It is inevitable that several Web services may either perish or fail before or during transactions. The completion of a composite process relies on the smooth execution of all constituent Web services. A mediator acts as an intermediary between providers and consumers to monitor the execution of these services. If a service fails, the mediator has to recover the whole composite process or else jeopardize achieving the intended goals. The atomic replacement of a perished Web service usually does not apply because the process of locating a matched Web service is unreliable. Even the system cannot depend on the replacement of the dead service with a composite service. In this paper, we propose an automatic renovation plan for failure recovery of composite semantic services based on an approach of subdigraph replacement. A replacement subdigraph is posed in lieu of an original subdigraph, which includes the failed service. The replacement is done in two separate phases, offline and online, to make the recovery faster. The offline phase foresees all possible subdigraphs, pre-calculates them, and ranks several possible replacements. The online phase compensates the unwanted effects and executes the replacement subdigraph in lieu of the original subdigraph. We have evaluated our approach during an experiment and have found that we could recover more than half of the simulated failures. These achievements show a significant improvement compared to current approaches.     

Response-time analysis of composite Web services

Web services let programs submit requests to other programs over the Internet via open protocols and standards. Many traditional Web sites, including popular search engines like Google and large online bookstores are boosting their traffic through Web service APIs. A single Internet application can invoke many different Web services - for example, the metasearch engine WebSifter uses several online ontologies to refine a user's request into a more meaningful query and then submits that query to various search engines in parallel. We call such applications composite Web services. Many important challenges stem from the quality-of-service issues in composite Web services. We address the impact of slow services on the overall response time of a transaction that uses several Web services in parallel.     

Enabling commerce on the Internet

For several years, electronic commerce has been a much-touted goal for the Internet. Not long ago, the Internet was used primarily for research, with access limited mainly to the university and research communities. But network service providers and commercial online services have opened it to a much larger user community. Many companies have set up corporate Web pages, and we have started to see credit cards and other monetary instruments used to place orders over the network. The Internet is increasingly becoming a venue for conducting the commerce previously carried out by other means, and for offering new commercial online services     

Improving availability and performance with application-specific data replication

The emerging edge services architecture promises to improve the availability and performance of Web services by replicating servers at geographically distributed sites. A key challenge in such systems is data replication and consistency, so that edge server code can manipulate shared data without suffering the availability and performance penalties that would be incurred by accessing a traditional centralized database. This work explores using a distributed object architecture to build an edge service data replication system for an e-commerce application, the TPC-W benchmark, which simulates an online bookstore. We take advantage of application-specific semantics to design distributed objects that each manages a specific subset of shared information using simple and effective consistency models. Our experimental results show that by slightly relaxing consistency within individual distributed objects, our application realizes both high availability and excellent performance. For example, in one experiment, we find that our object-based edge server system provides five times better response time over a traditional centralized cluster architecture and a factor of nine improvement over an edge service system that distributes code but retains a centralized database.     

Web服务组合的可靠性动态评估模型*

为了合理、高效、动态地评估Web服务组合的可靠性,为服务请求者提供高质量的组合服务,提出了一个Web服务组合的可靠性动态评估模型。该模型对服务提供者发布至UDDI注册中心的Web服务进行语义预先处理,根据语义Web服务间的逻辑组合关系,基于预推理技术构造Web服务的自动组合框架,提出了Web服务的自动组合算法,建立Web服务组合方案的路径结构;利用随机Petri网对满足服务请求者需求的服务组合路径结构进行可靠性建模,结合在线获取的Web服务可靠性信息,对Web服务组合的可靠性进行动态评估。实验示例结果分析表明,提出的模型能确保Web服务组合方案的有效性和提高服务组合的效率,对Web服务组合的可靠性评估具有较强动态性和灵活适应性。     

Managing Information for Effective Business Partner Relationships

Partner Relationship Management (PRM) is an information strategy that employs a set of applications focused on directly impacting an enterprise and its business partners' sales and services. Web services employ a distributed computing architecture that consists of many different computers that communicate over the Internet to form one system. the communication standards and protocols used in Web services are universally accepted. These Web services can be requested by client applications: Web based, windows, or mobile devices. This article presents an overview of PRM and Web services, and discusses the potential for improving partner relationship processes through the use of Web services.     

A methodological approach for designing and evaluating intelligent applications for digital collections

The rapid evolution of Internet services has led to a constantly increasing number of Web sites and to an increase in the available information. The main challenge is to support Web users in order to facilitate navigation through Web sites and to improve searching among the extremely large Web repository, such as digital libraries, online product catalogues, or other generic information sources. The complexity of today's services could be lowered by means of proactive support or advice from the system. The proactiveness could be achieved using dialoguing agents that exploit user profiles to provide personal recommendations. In this paper, we will present a general methodology to cover the entire process of designing advanced solutions for online services. The methodology has been adopted to elicit user requirements for the system developed in the COGITO project, and to evaluate the performance of the final prototype.     

Web services: e-commerce partner integration

Online retailers have used a succession of technologies to showcase their products and services on the Web. That experience gives them a greater insight into what it is that the latest technology, Web services, can offer them. This article gives a brief survey of the evolution of evolving e-commerce technologies, explaining what each offered and could not offer to retailers. It then describes how Amazon's investment in its e-commerce services (ECS) gives Amazon partners access to common online retailing functionalities. These researchers also present the partner integration framework they developed to help retailers define what services they need in an online retail system.     

XML-based specification for Web services document security

The Internet and related technologies have seen tremendous growth in distributed applications such as medicine, education, e-commerce, and digital libraries. As demand increases for online content and integrated, automated services, various applications employ Web services technology for document exchange among data repositories. Web services provide a mechanism to expose data and functionality using standard protocols, and hence to integrate many features that enhance Web applications. XML, a well-established text format, is playing an increasingly important role in supporting Web services. XML separates data from style and format definition and allows uniform representation, interchange, sharing, and dissemination of information content over the Internet. XML and Web services provide a simplified application integration framework that drives demand for models that support secure information interchange. Providing document security in XML-based Web services requires access control models that offer specific capabilities. Our XML-based access control specification language addresses a new set of challenges that traditional security models do not address.     

A bio-inspired emergent system for intelligent Web service composition and management

Some important mechanisms in neuroendocrine-immune (NEI) system are inspired to design a decentralized, evolutionary, scalable, and adaptive system for Web service composition and management. We first abstract a novel intelligent network model inspired from the NEI system. Based on this model, we then propose a method for Web service emergence by designing a bio-entity as an autonomous agent to represent Web service. As such, automatic composition and dynamic management of Web services can be achieved. Also, we build its computation platform which allows the bio-entities to cooperate over Web services and exploits capabilities of their partners. Finally, the simulation results on the platform show that Web service emergence can be achieved through self-organizing, cooperating, and compositing. The proposed method provides a novel solution for intelligent composition and management of Web services.