Spammers e-mail in bulk using automatic e-mail-sending programs. Spammers must first obtain e-mail addresses and sources for e-mail addresses include joining mailing lists to gather addresses from the mailing list software, purchasing mail lists from other spammers on CD-ROM (which can contain millions of addresses), and spambots (or harvesters) which scan Internet newsgroups and Web pages for e-mail addresses.
Published in Chapter:
Semantic Web Services
Juan Manuel Adán-Coello (Pontifícia Universidade Católica de Campinas, Brazil)
Copyright: © 2009
|Pages: 6
DOI: 10.4018/978-1-60566-014-1.ch174
Abstract
Service-oriented computing (SOC) is a new computing paradigm that uses services as building blocks to accelerate the development of distributed applications in heterogeneous computer environments. SOC promises a world of cooperating services where application components are combined with little effort into a network of loosely coupled services for creating flexible and dynamic business processes that can cover many organizations and computing platforms (Chesbrough & Spohrer, 2006; Papazoglou & Georgakopoulos, 2003). From a technical point of view, the efforts to offer services have focused on the development of standards and the creation of the infrastructure necessary to describe, discover, and access services using the Web. This type of service is usually called a Web service. The availability of an abundant number of Web services defines a platform for distributed computing in which information and services are supplied on demand, and new services can be created (composed) using available services. Nevertheless, the composition of Web services involves three fundamental problems (Sycara, Paolucci, Ankolekar, & Srinivasan, 2003): 1. To elaborate a plan that describes how Web services interact, how the functionally they offer can be integrated to provide a solution to the considered problem. 2. To discover Web services that accomplish the tasks required by the plan. 3. To manage the interaction of the chosen services. Problems 2 and 3 are of responsibility of the infrastructure that supports the composition of services, while the first problem is of responsibility of the (software) agents that use the infrastructure. The discovery and interaction of Web services poses two main challenges to the infrastructure: 1. How to represent Web services capabilities and how to recognize the similarities between service capabilities and the required functionalities. 2. How to specify the information a Web service requires and provides, the interaction protocol, and the low-level mechanisms required to service invocation.