Deploying ontologies in software design

In this thesis we will be concerned with the relation between ontologies and software design. Ontologies are studied in the arti cial intelligence community as a means to explicitly represent standardised domain knowledge in order to enable knowledge sharing and reuse. We deploy ontologies in software design with emphasis on a traditional software engineering theme: error detection. In particular, we identify a type of error that is often di cult to detect: conceptual errors. These are related to the description of the domain whom which the system will operate. They require subjective knowledge about correct forms of domain description to detect them. Ontologies provide these forms of domain description and we are interested in applying them and verify their correctness(chapter 1). After presenting an in depth analysis of the eld of ontologies and software testing as conceived and implemented by the software engineering and arti cial intelligence communities(chapter 2), we discuss an approach which enabled us to deploy ontologies in the early phases of software development(i.e., speci cations) in order to detect conceptual errors(chapter 3). This is based on the provision of ontological axioms which are used to verify conformance of speci cation constructs to the underpinning ontology. To facilitate the integration of ontology with applications that adopt it we developed an architecture and built tools to implement this form of conceptual error check(chapter 4). We apply and evaluate the architecture in a variety of contexts to identify potential uses(chapter 5). An implication of this method for deploying ontologies to reason about the correctness of applications is to raise our trust in the given ontologies. However, when the ontologies themselves are erroneous we might fail to reveal pernicious discrepancies. To cope with this problem we extended the architecture to a multi-layer form(chapter 4) which gives us the ability to check the ontologies themselves for correctness. We apply this multi-layer architecture to capture errors found in a complex ontologies lattice(chapter 6). We further elaborate on the weaknesses in ontology evaluation methods and employ a technique stemming from software engineering, that of experience management, to facilitate ontology testing and deployment(chapter 7). The work presented in this thesis aims to improve practice in ontology use and identify areas to which ontologies could be of bene ts other than the advocated ones of knowledge sharing and reuse(chapter 8). ii Acknowledgements I should start with the most signi cant acknowledgement which goes to my excellent supervisors David Robertson and Austin Tate. Their guidance and support was a second-to-none experience for me. David in particular has devoted a good deal of time to help me materialise the promising ideas and separate them from the less promising ones. His guidance and encouragement helped me go through the most arduous phases of my research. His countless questions and comments helped me convey my ideas in a more coherent manner. Austin's sense of direction and general understanding of how things t together in the big picture of science has always been an inspiration for me. I should also thank my thesis examiners John Lee and Enrico Motta. They gave me the pleasure to enjoy a thought-provoking VIVA. A successful research project is never carried out in complete isolation. My membership in the Software Systems and Processes(SSP) research group in Edinburgh was a great apprenticeship for me. It has been a continuous source of inspiration and i enjoyed working along with bright people who have also been very good friends. Steve Polyak, Renaud Lecoeuche, Edjard Mota, Alberto Castro, Stefan Daume, Jessica Chen-Burger, Virginia Biris-Brilhante, Daniela Carbogim, Jo~ ao Cavalcanti, Chris Lin, Josef Leung, Wamberto Vasconcelos are all past and present incarnations of this magni cent group. In particular, Steve's and Virginia's common interests in the world of ontologies was an endless source of fruitful discussions, Renaud's ideas on requirements engineering helped me formulate early ideas, Stefan and Jo~ao shared visions with me for the Internet era, Daniela and Virginia provided much feedback in the computational logic realm. One of the great experiences being member of the SSP group is probably its unparallelled family feeling. I made great friendships with most of my colleagues for the years to come which are di cult to forget. I will especially remember Daniela's permanent smile and amazingly good mood which was an oasis during those endless and murky winter days in Edinburgh. I have also bene ted from being a member of the Department of Arti cial Intelligence(AI) in Edinburgh. It is probably the best research centre in Europe and among the best in the world for AI. The countless seminars and talks that i attended is only a small fraction of the excellent facilities provided. I should also mention that the Department is located in one of the most beautiful cities in the world: Edinburgh is a stunning city. Thanks to other members of the infamous E17 \PhDs room" in South Bridge for their friendship and support throughout the duration of the project: Daqing He, Hua Cheng, Gerhard Wickler, Hasan Kamal, Finlay Smith, Sonia Schulenburg, Elias Biris to mention just a few. I enjoyed presenting parts of this thesis in conferences, workshops and i had the pleasure to give invited talks and participate in a panel discussion. I thank all those colleagues with whom i enjoyed discussions and collaboration over the last three years: Tim Menzies, Klaus-Dieter Altho , Enrico Motta, Dieter Fensel, Frank van Harmelen, Richard Benjamins, Derek Sleeman, Alun Preece, Mike Uschold were all supportive with their constructive criticism and insight. This research was supported by a European Commission's Marie Curie Research Feliii lowship under the programme Training and Mobility of Researchers. Their nancial support made this project materialise. Finally i would like to thank all my personal friends and my family back in Athens, Greece who have been marvellously supportive and patient all those years: Spyros, Leonidas, Nikos, Alexis, Dimitris, Vivi, and Pavlin. I am especially indebted to my family Thodoris, Nina and Tassos who made me feel like i had never left home. iv Declaration I hereby declare that I composed this thesis entirely myself and that it describes my own research. Yannis Kalfoglou Edinburgh June 13, 2000 v