SCHOOL OF COMPUTER SCIENCE Semantic Wiki for Travel and Holidays using OWL Project Initial Report COMP60990 Student Name: Joao Rafael Goncalves Student Number: 7387762 Supervisor(s): Prof. Alan Rector Dr. Robert Stevens Date: 27-Apr-2009 Table Of Contents Table Of Contents.................................................................................................2 1. Abstract..........................................................................................................3 2. Introduction...................................................................................................4 3. Background and related literature..............................................................6 3.1 Semantic Wiki approaches ......................................................................6 3.2 Wiki Architectures...................................................................................7 3.2.1 General structure of a Wiki ...................................................................... 7 3.2.2 General structure of a Semantic Wiki....................................................... 8 3.3 Types of Semantic Wikis.........................................................................8 3.4 Semantic Wiki implementations..............................................................9 3.4.1 Features Overview.................................................................................... 9 3.4.2 Semantic MediaWiki .............................................................................. 10 3.4.3 BOWiki................................................................................................... 11 3.4.4 IkeWiki ................................................................................................... 12 4. Research Methods .......................................................................................14 4.1 Project Overview ...................................................................................14 4.2 Objectives ..............................................................................................14 4.3 Project Plan............................................................................................16 4.4 Tools and methodologies.......................................................................17 4.4.1 Project stages .......................................................................................... 17 4.4.2 Tools ....................................................................................................... 17 4.4.3 Implementation....................................................................................... 18 4.4.4 Testing .................................................................................................... 18 4.4.5 Extensions............................................................................................... 19 4.5 Summary................................................................................................20 5. References ....................................................................................................21 6. Appendices...................................................................................................23 6.1 Appendix A – Wiki Matrix....................................................................23 2 1. Abstract This project aims at exploring the use of Semantic Wikis for authoring and reasoning over an OWL-DL ontology in a collaborative environment. A number of wiki implementations are here analysed and compared to determine their suitability for extending to this purpose. Semantic wikis allow users to add semantic annotations to wiki content. These annotations provide conceptual or individual information about a wiki page, and its relationships to other pages. The expressivity of annotations varies in most wikis, however this report focuses on OWL ontologies. Using an ontology provides the wiki with an underlying model of its domain’s knowledge, in this case ‘Travel and Holidays’. It is also useful to classify and verify the consistency of the data in the pages, which is done by means of a reasoner. Automated reasoners classify and infer whether new wiki entries are consistent with the knowledge base before storing them. The implementation proposed in this report consists of enhancing and adapting two semantic wikis to make better use of OWL and reasoning; IkeWiki and BOWiki . The wikis’ functionality will be tested in regards to adding and editing OWL individuals ( ABox ), as well as concepts ( TBox ). Depending on this, either one or both wikis will be adapted to use the Travel ontology, supplied by Dr. Robert Stevens. The ‘Travel wiki’ will subsequently be tested in a collaborative environment, where multiple users author wiki content. This is carried out as outlined in example pages, and also a video demonstration of wiki features. The project will draw conclusions on the usability of the wiki as a collaborative authoring tool for OWL ontologies. The ability to engineer the knowledge contained in an ontology from a semantic wiki brings the added benefits of online collaboration combined with a user-friendly web interface. Furthermore, querying and reasoning over an ontology add powerful capabilities that allow a more advanced and widespread use of wikis as support tools for authoring knowledge. 3 2. Introduction The purpose of this project is to develop a Semantic Wiki, based on a travel ontology provided by Dr. Robert Stevens, which makes extensive use of reasoning both about classes and individuals. The first part of the project, covered in this report, involves a survey of existing semantic media wiki projects and software, in order to make recommendations for the implementation in the subsequent part of the project. This second part of the project entails the installation and testing of a wiki implementation, so as to finally adapt it to make better use of OWL1 (Web Ontology Language) and reasoning. Over the initial phase of the project several wiki applications have been analysed and compared. The most relevant wiki applications to this project’s goal will be discussed in the Background section, more specifically these wikis should be reusable – so as to extend it to the ontology domain of the project – and provide advanced reasoning capabilities in OWL-DL. Furthermore, the intended wiki is meant to be intuitive and user-friendly, to the point that collaborative authoring of the knowledge base is as simple and straightforward as possible. If entering content in the wiki is made a complex task, then adherence to a particular style may not be always possible. So in terms of adding and editing entries, the best approach would be wizard or form-like interfaces, in order to facilitate what is likely to be the most stressful part of knowledge- authoring in wikis. The first notion of a wiki came to be implemented in 1995 by Ward Cunningham, with the launch of WikiWikiWeb 2. It was then defined as an intelligible piece of software that would provide a simple way to collaboratively describe, author, and collect information [1]. Wikipedia 3 is currently the most popular implementation of a wiki, consisting of a multitude of articles in several languages, and a large online community committed to its development. The notion of community-driven contributions is what defines a wiki as a collaborative authoring tool; its pages are written through contributions of not one but several people or organised groups worldwide. Wikipedia is based on the MediaWiki4 wiki engine, which comprises several features to support collaboration; such as recent changes in the wiki, revision history of pages, change tracking, and list of contributions by specific users. The knowledge contained in a wiki is typically represented in HTML 5 pages, comprised of natural-language text and hyperlinks. Having no embedded formal definition of itself or how it relates to other pages and resources, a wiki article has very little machine- readable information that one can re-use. The querying capability of a regular wiki is an example of this; searching pages in a wiki is done by entering article names (or approximations thereof). It is possible to search Wikipedia for the entry of ‘Athens’ or other city names, but unless such a page has been manually compiled it is not possible to query Wikipedia for a ‘list of all Greek cities’. So despite the amount of information gathered in a regular wiki, it is not structured in a way that allows for article retrieval in this complex way. 1 http://www.w3.org/TR/owl-features/ [accessed on 10/02/09] 2 http://c2.com/cgi/wiki [accessed on 19/03/09] 3 http://en.wikipedia.org/wiki/Main_Page [accessed on 05/02/09] 4 http://www.mediawiki.org/wiki/MediaWiki [accessed on 05/02/09] 5 http://www.w3.org/TR/html401/ [access on 17/02/09] 4 On this tone, a Semantic Wiki will be introduced as an extended version of a wiki, with technologies developed by the Semantic Web community, and providing the ability to describe resources in a formal language. The describing of resources, also known as annotating , consists of associating metadata (information about information) with resources in a wiki page. “By adding metadata to ordinary Wiki content, users get added benefits such as improved retrieval, information exchange, and knowledge reuse” [2]. So unlike a regular Wiki, it is possible to author more than just text and links; semantic wikis capture machine-readable information about the data in its pages, as well as the relations between them [3]. This way, the