DESIDOC Journal of Library & Information Technology, Vol. 28, No. 3, May 2008, pp. 47-55 © 2008, DESIDOC 47 Received on 26 April 2007; Revised on 21 May 2007 Semantic Web Services: A Study of Existing Technologies, Tools and Projects Biswanath Dutta Documentation Research and Training Centre Indian Statistical Institute, Bangalore-560 059 E-mail: bisu@drtc.isibang.ac.in ABSTRACT Semantic web service (SWS) is an extension of the web service with an explicit representation of meanings. It promises to increase the level of automation and has ability to integrate and reuse diverse information resources relevant to a given situation in a cost-effective way. It has the potentiality to change the way knowledge and business services are consumed and provided on the web. This paper presents state- of-the-art of current enabling SWS technologies. Discusses about the exiting important initiatives for SWS approaches and gives a comparative study between two important SWS approaches. It also discusses about some of the established tools and projects on different facets of SWS. Keywords: Semantic web, web services, SWS, SWS technologies, OWL-S, WSMO. 1. INTRODUCTION Web is a large, disjointed reservoir of information composed of unsystematically interrelated repositories associated with particular domains and enterprises. It was designed for human interpretation and use. The stored information in it is not semantically rich, which would facilitate its retrieval automatically or semi-automatically. To address this deficiency of the web, in the last few years two revolutionary concepts have emerged; one is web service and the other is semantic web. The web service technology is a uniform technology that allows uniform and universal access via Web standards to software components residing on various platforms and written in different programming languages. These are well-defined, reusable, software components that perform specific, encapsulated tasks via standarised web oriented mechanism. But the major drawbacks of the web service technologies are their inability to automatic discovery and composition; human intervention and effort is required which make them unusuable in the complex business environment. The current standard technologies for web services (e.g. WSDL) provide only syntactical description of their functionalities, without any definition about what the syntactic definition might mean. Semantic web technology has drawn a considerable attention of the researchers in the field of distributed information systems, artificial intelligence, and so on. Researchers are taking interest to make use of semantic web technology as a central component of their software constructions. As mentioned in the previous paragraph that the web services are lacking the semantic description, the semantic web researchers have proposed to augment web services with a semantic description of their functionality in order to facilitate their discovery and integration. This technology, combination of web services with semantic web technology, is referred as semantic web services (SWS). 1 SWS is, therefore, an extension of web service with an explicit representation of meanings. SWS