Semantic Web Services (eBook)

Rudi Studer is Full Professor in Applied Informatics at the University of Karlsruhe, Germany. His research interests include knowledge management, Semantic Web technologies and applications, ontology management, data and text mining, service-oriented architectures, peer-to-peer systems, and Semantic Grid. Rudi Studer is also director in the research department Information Process Engineering at the FZI Research Center for Information Technologies at the University of Karlsruhe and one of the presidents of the FZI Research Center as well as co-founder of the spin-off company ontoprise GmbH that develops semantic applications. He is engaged in various national and international cooperation projects being funded by e.g. Deutsche Forschungsgemeinschaft (DFG), the European Commission, the German Ministry of Education and Research, and industry. He is president of the Semantic Web Science Association and Editor-in-chief of the journal Web Semantics: Science, Services, and Agents on the World Wide Web.

Contents 5
Introduction 7
Part I Web Services Technology 19
1 Towards Service-Oriented Architectures 21
2 Architecture and Standardisation of Web Services 31
Part II Semantic Web Technology 56
3 Knowledge Representation and Ontologies 57
4 Ontology Development 113
5 Semantic Annotation of Resources in the Semantic Web 141
Part III Semantic Web Services 163
6 Goals and Vision 165
7 Description 185
8 Discovery 217
9 Composition 251
10 Mediation 293
Part IV Tools and Use Cases 316
11 Tools for Semantic Web Services 317
12 Ontology-Based Change Management in an eGovernment Application Scenario 345
13 An eGovernment Case Study 371
14 An eHealth Case Study 387
Glossary 409
Index 411

1 Towards Service-Oriented Architectures (p. 15)

Stefan Fischer and Christian Werner
Institute for Telematics, University of Lübeck
Summary.
This chapter is meant as a motivation of why and how Web Services have evolved. Starting from the increasing need for integration of IT solutions, we argue that Web Services have something to offer, especially for the important fields of Business-to-Business (B2B) and Enterprise Application Integration (EAI). However, this is only the beginning of a new road, leading to the radically new software technology of Service-Oriented Architectures (SOA).

1.1 Integration: The New Challenge

This book is about SemanticWeb Services, and before we can talk about the new and fascinating "semantics" part, it will be helpful to consider the foundations, namely to look at the Web Service technology itself. Web Services themselves are a relatively new phenomenon and have been under development for only slightly more than five years.

During this time, they have gained a lot of attention and have also already gone through their hype phase. Meanwhile, they are accepted as one of the most important technologies when talking about application integration. In this context, they have been brought together with many other buzzwords that have been coming up in recent years.

1.1.1 The Need for Integration

First, Web Services have been considered as a new kind of middleware, taking their place between application and network. Here, they are in competition with other similar approaches such as CORBA, Java RMI, OSF DCE, etc. One can very well argue that Web Services have an excellent chance to become the dominating middleware, due to their extensive support of Internet technologies – one of the most important and relatively rarely mentioned being the use of URIs/URLs as addressing scheme – and the massive support by IT industry, resulting, for instance, in an excellent tool chain support throughout the software life cycle.

Second, Web Services have been chosen as one of the base technologies in grid computing, another major recent buzzword. A computing or storage grid works just like a water or electrical grid – just press a button and the grid delivers as much water or power as you need. In IT terms, you just plug in your terminal and get as much storage capacity or computing power as you need.

The resources will be provided by the grid, which consists of some cooperation software and lots of more or less powerful computers. As a user, you do not see the computers, you just see the grid (or the plug) and its services. And grid services are provided as Web Services, so that is where they come into the game. Whenever your grid application makes use of one of the grid’s services, it calls a Web Service.

Third and final example, Web Services are the basic component in most SOA approaches. SOA means Service-Oriented Architecture, and it is the latest hype in enterprise application software architecture design. SOA will most likely become one of the most important technologies within the next few years.