Abstract
Web services are paving the way for a new type of business applications. This can be noticed from the large number of standards and initiatives related to Web services (Margaria, 2007; Papazoglou et al., 2007; Yu et al., 2008), which tackle a variety of issues such as security, fault tolerance, and substitution. These issues hinder the automatic composition of Web services. Composition handles the situation of a user’s request that cannot be satisfied by any single, available Web service, whereas a composite Web service obtained by combining available Web services may be used. Despite the tremendous capabilities that empower Web services, they still lack some capabilities that would propel them to a higher level of adoption by the IT community and make them compete with other integration middleware like CORBA and .Net. As a result, Web services adoption could be slowed down if some issues such as the complexity of their discovery are not properly addressed (Langdom, 2003). For this particular issue of discovery, we examine in this chapter the use of social networks (Ethier, visited in 2008; Wasserman and Glaskiewics, 1994). Such networks permit to establish between people relationships of different types like friendship, kinship, and conflict. These relationships are dynamic and, hence, adjusted over time depending on different factors like outcomes of previous interaction experiences, and natures of partners dealt with. Replacing people with Web services is doable since Web services constantly engage in different types of interaction sessions with users and peers as well
TopBrief Literature Review
Social networks have been used in different domains ranging from social sciences to artificial intelligence and e-business. According to Ethier, “the study of social networks is important since it helps us to better understand how and why we interact with each other, as well as how technology can alter this interaction. The field of social network theory has grown considerably during the past few years as advanced computing technology has opened the door for new research” (Ethier, visited in 2008).
Key Terms in this Chapter
Universal Description, Discovery, and Integration: UDDI specifications define how Web services should be published and discovered by providers and users, respectively. At the conceptual level, information provided in an UDDI registry consists of three components. First, white pages include address, contact, and known identifiers of Web services. Second, yellow pages include industrial categories based on standardized taxonomies. Finally, green pages include the technical information that a provider would like to offer on its Web services. At the business level, an UDDI registry can be used for checking whether a given provider has particular Web services, finding companies in a certain industry with a given type of Web service, and locating information about how a provider has exposed a Web service.
Electronic Business Using eXtensible Markup Language. ebXML: A family of XML-based standards sponsored by OASIS and UN/CEFACT whose mission is to provide an open, XML-based infrastructure that enables the global use of electronic business information in an interoperable, secure, and consistent manner by all trading partners (http://en.wikipedia.org/wiki/EbXML).
Composite Web Service: Composition targets users’ requests that cannot be satisfied by any single, available Web service, whereas a composite Web service obtained by combining available Web services may be used. Several specification languages to compose Web services exist for example WS-BPEL (de facto standard), WSCDL, and XLANG. A composite Web service could be built either proactively or reactively. The former is an off-line process that gathers available component Web services in-advance to form a composite Web service. This one is pre-compiled and ready for execution upon users’ requests. The latter creates a composite Web service on-the-fly upon users’ requests. Because of the on-the fly property, a dedicated module is in charge of identifying the needed component Web services, making them collaborate, tracking their execution, and resolving their conflicts if they arise.
Web Service: It is “a software application identified by a URI, whose interfaces and binding are capable of being defined, described, and discovered by XML artifacts, and supports direct interactions with other software applications using XML-based messages via Internet-based applications’’ (W3C). A Web service implements a functionality (e.g., BookOrder and WeatherForecast) that users and other peers invoke by submitting appropriate messages to this Web service. The life cycle of a Web service could be summarized with five stages namely description, publication, discovery, invocation, and composition. Briefly, providers describe their Web services and publish them on dedicated registries. Potential consumers (i.e., requesters) interact with these registries to discover relevant Web services, so they could invoke them. In case the discovery fails, i.e., requests cannot be satisfied by any single Web service, the available Web services may be composed to satisfy the consumer’s request.
Recommender systems: They are designed to help users tackle the problem of information overload. They could be built upon three representative techniques namely content-based, collaborative-filtering, and hybrid.