Semantic Web Technologies Trends and Research in Ontology-based Systems

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1 Semantic Web Technologies Trends and Research in Ontology-based Systems John Davies BT, UK Rudi Studer University of Karlsruhe, Germany Paul Warren BT, UK

3 Semantic Web Technologies

5 Semantic Web Technologies Trends and Research in Ontology-based Systems John Davies BT, UK Rudi Studer University of Karlsruhe, Germany Paul Warren BT, UK

6 Copyright # 2006 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, England Telephone (þ44) (for orders and customer service enquiries): cs-books@wiley.co.uk Visit our Home Page on All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the permission in writing of the Publisher. Requests to the Publisher should be addressed to the Permissions Department, John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England, or ed to permreq@wiley.co.uk, or faxed to (þ44) This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the Publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Other Wiley Editorial Offices John Wiley & Sons Inc., 111 River Street, Hoboken, NJ 07030, USA Jossey-Bass, 989 Market Street, San Francisco, CA , USA Wiley-VCH Verlag GmbH, Boschstr. 12, D Weinheim, Germany John Wiley & Sons Australia Ltd, 42 McDougall Street, Milton, Queensland 4064, Australia John Wiley & Sons (Asia) Pte Ltd, 2 Clementi Loop #02-01, Jin Xing Distripark, Singapore John Wiley & Sons Canada Ltd, 22 Worcester Road, Etobicoke, Ontario, Canada M9W 1L1 Library of Congress Cataloging-in-Publication Data Davies, J. (N. John) Semantic Web technologies : trends and research in ontology-based systems / John Davies, Rudi Studer, Paul Warren. p. cm. Includes bibliographical references and index. ISBN-13: (cloth : alk. paper) ISBN-10: (cloth : alk. paper) 1. Semantic Web. I. Studer, Rudi. II. Warren, Paul. III. Title: Trends and research in ontology-based systems. IV. Title. TK D dc British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN-13: ISBN-10: Typeset in 10/11.5 pt Palatino by Thomson Press (India) Ltd, New Delhi, India Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire This book is printed on acid-free paper responsibly manufactured from sustainable forestry in which at least two trees are planted for each one used for paper production.

7 Contents Foreword xi 1. Introduction Semantic Web Technologies The Goal of the Semantic Web Ontologies and Ontology Languages Creating and Managing Ontologies Using Ontologies Applications Developing the Semantic Web 8 References 8 2. Knowledge Discovery for Ontology Construction Introduction Knowledge Discovery Ontology Definition Methodology for Semi-automatic Ontology Construction Ontology Learning Scenarios Using Knowledge Discovery for Ontology Learning Unsupervised Learning Semi-Supervised, Supervised, and Active Learning Stream Mining and Web Mining Focused Crawling Data Visualization Related Work on Ontology Construction Discussion and Conclusion 24 Acknowledgments 24 References Semantic Annotation and Human Language Technology Introduction Information Extraction: A Brief Introduction 31

8 vi CONTENTS Five Types of IE Entities Mentions Descriptions Relations Events Semantic Annotation What is Ontology-Based Information Extraction Applying Traditional IE in Semantic Web Applications AeroDAML Amilcare MnM S-Cream Discussion Ontology-based IE Magpie Pankow SemTag Kim KIM Front-ends Deterministic Ontology Authoring using Controlled Language IE Conclusion 48 References Ontology Evolution Introduction Ontology Evolution: State-of-the-art Change Capturing Change Representation Semantics of Change Change Propagation Change Implementation Change Validation Logical Architecture Data-driven Ontology Changes Incremental Ontology Learning Usage-driven Ontology Changes Usage-driven Hierarchy Pruning Conclusion 68 References Reasoning With Inconsistent Ontologies: Framework, Prototype, and Experiment Introduction Brief Survey of Approaches to Reasoning with Inconsistency Paraconsistent Logics 73

9 CONTENTS vii Ontology Diagnosis Belief Revision Synthesis Brief Survey of Causes for Inconsistency in the Semantic Web Inconsistency by Mis-representation of Default Inconsistency Caused by Polysemy Inconsistency through Migration from Another Formalism Inconsistency Caused by Multiple Sources Reasoning with Inconsistent Ontologies Inconsistency Detection Formal Definitions Selection Functions Strategies for Selection Functions Syntactic Relevance-Based Selection Functions Prototype of Pion Implementation Experiments and Evaluation Future Experiments Discussion and Conclusions 91 Acknowledgment 92 References Ontology Mediation, Merging, and Aligning Introduction Approaches in Ontology Mediation Ontology Mismatches Ontology Mapping Ontology Alignment Ontology Merging Mapping and Querying Disparate Knowledge Bases Mapping Language A (Semi-)Automatic Process for Ontology Alignment OntoMap: an Ontology Mapping Tool Summary 111 References Ontologies for Knowledge Management Introduction Ontology Usage Scenario Terminology Data Qualia Sorts of Data Ontologies as RDBMS Schema Topic-ontologies Versus Schema-ontologies Proton Ontology Design Rationales 126

10 viii CONTENTS Basic Structure Scope, Coverage, Compliance The Architecture of Proton Topics in Proton Proton Knowledge Management Module Conclusion 135 References Semantic Information Access Introduction Knowledge Access and the Semantic WEB Limitations of Current Search Technology Role of Semantic Technology Searching XML Searching RDF Exploiting Domain-specific Knowledge Searching for Semantic Web Resources Semantic Browsing Natural Language Generation from Ontologies Generation from Taxonomies Generation of Interactive Information Sheets Ontology Verbalisers Ontogeneration Ontosum and Miakt Summary Generators Device Independence: Information Anywhere Issues in Device Independence Device Independence Architectures and Technologies DIWAF SEKTAgent Concluding Remarks 166 References Ontology Engineering Methodologies Introduction The Methodology Focus Definition of Methodology for Ontologies Methodology Documentation Evaluation Past and Current Research Methodologies Ontology Engineering Tools Discussion and Open Issues Diligent Methodology Process Argumentation Support 183

11 CONTENTS ix 9.5. First Lessons Learned Conclusion and Next Steps 186 References Semantic Web Services Approaches and Perspectives Semantic Web Services A Short Overview The WSMO Approach The Conceptual Model The Web Services Modeling Ontology (WSMO) The Language The Web Service Modeling Language (WSML) The Execution Environment The Web Service Modeling Execution Environment (WSMX) The OWL-S Approach OWL-S Service Profiles OWL-S Service Models The SWSF Approach The Semantic Web Services Ontology (SWSO) The Semantic Web Services Language (SWSL) The IRS-III Approach Principles Underlying IRS-III The IRS-III Architecture Extension to WSMO The WSDL-S Approach Aims and Principles Semantic Annotations Semantic Web Services Grounding: The Link Between SWS and Existing Web Services Standards General Grounding Uses and Issues Data Grounding Behavioural Grounding Conclusions and Outlook 232 References Applying Semantic Technology to a Digital Library Introduction Digital Libraries: The State-of-the-art Working Libraries Challenges The Research Environment A Case Study: The BT Digital Library The Starting Point Enhancing the Library with Semantic Technology The Users View Implementing Semantic Technology in a Digital Library Ontology Engineering 250

12 x CONTENTS BT Digital Library End-user Applications The BT Digital Library Architecture Deployment View of the BT Digital Library Future Directions 255 References Semantic Web: A Legal Case Study Introduction Profile of the Users Ontologies for Legal Knowledge Legal Ontologies: State of the Art Ontologies of Professional Knowledge: OPJK Benefits of Semantic Technology and Methodology Architecture Iuriservice Prototype Conclusions 278 References A Semantic Service-Oriented Architecture for the Telecommunications Industry Introduction Introduction to Service-oriented Architectures A Semantic Service-orientated architecture Semantic Mediation Data Mediation Process Mediation Standards and Ontologies in Telecommunications etom SID Adding Semantics Case Study Broadband Diagnostics The B2B Gateway Architecture Semantic B2B Integration Prototype Prototype Implementation Conclusion 298 References Conclusion and Outlook Management of Networked Ontologies Engineering of Networked Ontologies Contextualizing Ontologies Cross Media Resources Social Semantic Desktop Applications 307 Index 309

13 Foreword Semantically Enabled Knowledge Technologies Toward a New Kind of Web Information technology has a surprising way of changing our culture radically often in ways unimaginable to the inventors. When Gutenberg developed moveable type in the middle of the fifteenth century, his primary goal was to develop a mechanism to speed the printing of Bibles. Gutenberg probably never thought of his technology in terms of the general dissemination of human knowledge via printed media. He never planned explicitly for printing presses to democratize the ownership of knowledge and to take away the monopoly on the control of information that had been held previously by the Church which initially lacked Gutenberg s technology, but which had at its disposal the vast numbers of dedicated personnel needed to store, copy, and distribute books in a totally manual fashion. Gutenberg sought a better way to produce Bibles, and as a result changed fundamentally the control of knowledge in Western society. Within a few years, anyone who owned a printing press could distribute knowledge widely to anyone willing to read it. In the late twentieth century, Berners-Lee had the goal of providing rapid, electronic access to the online technical reports and other documents created by the world s high-energy physics laboratories. He sought to make it easier for physicists to access their arcane, distributed literature from a range of research centers scattered about the world. In the process, Berners-Lee laid the foundation for the World Wide Web. In 1989, Berners-Lee could only begin imagine how his proposal to link technical reports via hypertext might someday change fundamentally essential aspects of human communication and social interaction. It was not his intention to revolutionize communication of information for e-commerce, for geographic reasoning, for government services, or for any of the myriad Web-based applications that we now take for granted.

14 xii FOREWORD Our society changed irreversibly, however, when Berners-Lee invented HTML and HTTP. The World Wide Web provides a dazzling array of information services designed for use by people and has become an ingrained part of our lives. There is another Web coming, however, where online information will be accessed by intelligent agents that will be able to reason about that information and communicate their conclusions in ways that we can only begin to dream about. This Semantic Web represents the next stage in the evolution of communication of human knowledge. Like Gutenberg, the developers of this new technology have no way of envisioning the ultimate ramifications of their work. They are, however, united by the conviction that creating the ability to capture knowledge in machine understandable form, to publish that knowledge online, to develop agents that can integrate that knowledge and reason about it, and to communicate the results both to people and to other agents, will do nothing short of revolutionize the way people disseminate and utilize information. The European Union has long maintained a vision for the advent of the "information society," supporting several large consortia of academic and industrial groups dedicated to the development of infrastructure for the Semantic Web. One of these consortia has had the goal of developing Semantically Enabled Knowledge Technologies (SEKT; bringing together fundamental research, work to build novel software components and tools, and demonstration projects that can serve as reference implementations for future developers. The SEKT project has brought together some of Europe s leading contributors to the development of knowledge technologies, data-mining systems, and technologies for processing natural language. SEKT researchers have sought to lay the groundwork for scalable, semiautomatic tools for the creation of ontologies that capture the concepts and relationships among concepts that structure application domains; for the population of ontologies with content knowledge; and for the maintenance and evolution of these knowledge resources over time. The use of ontologies (and of procedural middleware and Web services that can operate on ontologies) emerges as the fundamental basis for creating intelligence on the Web, and provides a unifying framework for all the work produced by the SEKT investigators. This volume presents a review and synopsis of current methods for engineering the Semantic Web while also documenting some of the early achievements of the SEKT project. The chapters of this book provide overviews not only of key aspects of Semantic Web technologies, but also of prototype applications that offer a glimpse of how the Semantic Web will begin to take form in practice. Thus, while many of the chapters deal with specific technologies such as those for Semantic Web services, metadata extraction, ontology alignment, and ontology engineering, the

15 FOREWORD xiii case studies provide examples of how these technologies can come together to solve real-world problems using Semantic Web techniques. In recent years, many observers have begun to ask hard questions about what the Semantic Web community has achieved and what it can promise. The prospect of Web-based intelligence is so alluring that the scientific community justifiably is seeking clarity regarding the current state of the technology and what functionality is really on the horizon. In this regard, the work of the SEKT consortium provides an excellent perspective on contemporary research on Semantic Web infrastructure and applications. It also offers a glimpse of the kinds of knowledge-based resources that, in a few years time, we may begin to take for granted just as we do current-generation text-based Web browsers and resources. At this point, there is no way to discern whether the Semantic Web will affect our culture in a way that can ever begin to approximate the changes that have resulted from the invention of print media or of the World Wide Web as we currently know it. Indeed, there is no guarantee that many of the daunting problems facing Semantic Web researchers will be solved anytime soon. If there is anything of which we can be sure, however, it is that even the SEKT researchers cannot imagine all the ways in which future workers will tinker with Semantic Web technologies to engineer, access, manage, and reason with heterogeneous, distributed knowledge stores. Research on the Semantic Web is helping us to appreciate the enormous possibilities of amassing human knowledge online, and there is justifiable excitement and anticipation in thinking about what that achievement might mean someday for nearly every aspect of our society. Mark A. Musen Stanford, California, USA January 2, 2006

Semantic Web Technologies Trends and Research in Ontology-based Systems

Semantic Web Technologies Trends and Research in Ontology-based Systems John Davies BT, UK Rudi Studer University of Karlsruhe, Germany Paul Warren BT, UK John Wiley & Sons, Ltd Contents Foreword xi 1.