TODE : A Dot Net Based Tool for Ontology Development and Editing

Transcription

1 TODE : A Dot Net Based Tool for Ontology Development and Editing Noman Islam 1, Muhammad Shahab Siddiqui 2, Zubair A. Shaikh 3 Center for Research in Ubiquitous Computing National University of Computer and Emerging Sciences Karachi, Pakistan 1 noman.islam@nu.edu.pk; 2 shahab.siddiqui@ieee.org; 3 zubair.shaikh@nu.edu.pk; Abstract Semantic Web is an initiative towards transforming the current world-wide-web such that contents over the web can be understood and processed by machines. Ontology is one of the vital components of semantic web. It provides the vocabulary of a particular domain so that web contents can be easily comprehend by machines. Over the years, a number of tools like Protégé, WebODE and Ontolingua have emerged that assist ontology developers in the creation of ontologies. Most of these tools have been developed in open source languages while Dot Net community is slow to react. The developers of open source languages are actively working on creation of supporting tools like reasoners, consistency checkers and visualizers. Due to the unavailability of any Dot Net based ontology editing tool, we don t see similar type of activity in Dot Net community. We believe that a Dot Net based ontology editor can work as a catalyst and will trigger further development of supporting software in Dot Net environment. In this paper, we have proposed a Dot Net based tool for ontology development and editing called TODE. The tool provides a simplified, W3C compliant, web based environment for ontology creation. Keywords: TODE, Ontology Editor, Dot Net based tool, Semantic Web, Profile Ontology I. INTRODUCTION The term Semantic Web has been coined by Tim Berners-Lee[1]. It is a vision that extends the capabilities of internet such that contents and resources over the web have precise meaning. Due to the meaning associated with web objects, machines will be able to understand the stuff over the web. Semantic Web is not a single technology and it comprises of a number of components including ontology languages (RDF/RDFS[2], OWL[3], etc.), editing tools (Protégé[4], Ontolingua[5], etc.) and standards (WSMO[6], OWL-S[7] etc.). Ontology plays an important part in realization of semantic web. It is a collection of concepts, attributes, relationships and axioms. Many tools have emerged over the year which helps in ontology creation and maintenance. Ontology editor assists the ontology developer by providing a number of facilities like a friendly user interface for ontology creation, a collaborative environment where multiple users can work together and support for reasoning and inferencing etc. Ontology editor also provides facility to import and export ontology in languages like RDF, DAML, OWL and OIL. In addition, some ontology editors support well defined methodology for ontology creation. For example, WebODE[8] is a well-known web based ontology editor that supports an ontology development methodology called Methontology[9] for ontology development. Despite the availability of a large number of ontology editing tools, it is observed that no tool is developed in Dot Net Environment. The availability of a tool in Dot Net Environment gives rise to development of supporting tools, visualizers, plug-ins, reasoning and inferencing tools. Due to un-availability of Dot Net based ontology editing tool, the Dot Net community is quiescent in this active area of research, while the open source community is very active in this area. For example, Protégé is a Java based tool, which has been extended further through a large number of plug-ins like tools for Natural Language Processing, reasoning and project management[10]. Realizing this demand, we developed TODE (Tool for Ontology Development and Editing), which is a Dot Net based ontology editor. In next sections, we will discuss our proposed ontology editing tool. First, related work in this area will be discussed and then we will move towards the discussion of its architecture. We will also discuss the implementation details. Finally, the paper will be concluded with future directions. II. RELATED WROK Over the last few years, a number of ontology editing tools have emerged that assists the ontology developers towards the development of ontology by providing a user friendly environment for ontology creation and management. These tools make the job easier for ontology developers by providing a well-defined methodology for ontology creation, support for reasoning, inferencing, visualization and collaboration etc. [11],[12],[13] and [14] has provided a comparison of these ontology editing tools. Protégé[4] is a well known and probably the most stable, desktop based ontology editing tool developed by Stanford University. It provides support for RDF(S) and OWL. In addition, the tool can be easily extended via its plug-in feature. Hence, ontology reasoners like Pellet can be attached with this tool. OntoEdit[15] developed by Ontoprise, is a multilingual ontology editor. It has the support for RDF(S) and DAML+OIL. In addition, the tool provides a well defined methodology for ontology creation. Isa Viz[16] is a desktop based ontology editor that provides visual graph based interface for ontology creation based on RDF models. Ontolingua[5] is a ontology tool developed by Stanford University that supports a number of ontology languages like

2 TABLE I. A COMPARISON OF ONTOLOGY EDITING TOOLS Tools Free Open Dot Net Import Export Source and Web Languages Languages Based Protégé RDF, OWL RDF, OWL, FLogic, CLIPS Inferencing Reasoning Tools OntoEdit DAML + DAML + OIL, (Free) OIL, RDFS RDFS Differential Ontology Editor (DOE) RDFS, OWL DAML+OIL, OIL, RDFS, OWL IsaViz RDF/XML, RDF/XML, N- N-Triples Triples Ontolingua DAML+OIL, DAML+OIL, KIF,CLIPS KIF, CLIPS Altova N-triples, N-triples, Semantic Works OWL, RDF and RDFS OWL, RDF and RDFS WebODE RDF(S), CLIPS, DAML+OIL, DAML+OIL, UML, OWL UML, OWL TopBraid RDBMS, OWL,RDF, Composer OWL, RDF XML Morla RDF, OWL RDF,OWL Hozo RDF, OWL (subset) OWL, RDF TODE RDF, OWL- Lite, N-3, RDBMS, N-Triple, RDF, OWL- Lite, N-Triple, N-3, RDBMS DAML and RDF(S). Altova Semantic Works[17] is a commercial ontology editing tool that provides support for OWL and RDF and also has visual features like syntactic and semantic error checking and context sensitive help. WebODE[8] proposed by University of Madrid, is a web based tool that provides a multi-user collaborative environment for ontology creation and editing. Topbraid Composer[18], developed by Top Quadrant is an enterprise level modeling software for ontology creation. The tool is fully compliant with W3C recommendations. OBO-Edit[19] proposed by Berkeley University, provides an easy to use ontology editing feature along with a built-in-reasoner and search tool. The tool is optimized for biological ontology formats. Hozo[20] developed by Osaka University is a multilingual ontology editor that provides distributed development of ontologies and also provides tool for ontology exploration i.e. Conceptual Map Generation. Table 1 provides a comparative study of some of the most popular ontology editing tool. We can easily conclude that most of the ontology editing tools has been developed in languages like C/C++ or Java. None of the existing tools have been developed in C#. In addition most of these tools are desktop based like Protégé, Altova Semantic Works. Ontolingua though is developed for web-based environment but provides a difficult multi-page interface for ontology creation. Realizing the issues associated with currently available ontology editors, we proposed TODE (Tool for Ontology Development and Editing). It is a Dot Net based, W3C compliant, web based ontology editor that provides a simplified and simple interface for ontology creation. It is based on AJAX hence it is very efficient and can work for low-bandwidth clients. MOBILE Figure 1. Architecture of TODE III. TODE - A DOT NET BASED TOOL FOR ONTOLOGY DEVELOPMENT AND EDITING Fig 1 shows the generalized architecture of TODE (Tool for Ontology Development and Editing). TODE is designed based on Model View Controller Architecture, which is suitable for further extension for other clients without making significant changes in business logic. The View Component is responsible for handling all the presentation logic. At the presentation layer, there can be different types of clients i.e. Windows Presentation Foundation (WPF) Application, Java Applet, J2ME Application etc. The controller s job is to manage the interaction between the model and view. All client requests will be received by controller that forwards its requests to Model, which contains the business logic. The business logic component handles all the necessary tasks required for ontology creation and maintenance. Fig 2 shows the web-interface of TODE. TODE provides an easy-to-use interface for modeling any domain knowledge through the use of hierarchy of classes, their attributes, relationships and instances. Ontologies can be created easily through a well-defined methodology that can be exported further to a number of languages like RDF, OWL-Lite, N- Triple, N-3, RDBMS etc. To simplify the ontology creation, a one-tabbed, AJAX based and consistent web interface is provided for ontology creation. This is in contrast to existing ontology development tools that provides a multi-tabbed or multi-page interface for ontology creation. To develop a simplified web-based interface, we have followed all the Human Computer Interaction (HCI) recommendations of W3C that are required for developing a user friendly web site. IV. MODEL Ontology storage / retrieval Notifies the view about changes in model VIEW DESKTOP Clients WEB Presentation of ontologies based on the capability of client Interaction with model and controller IMPLEMENTATION DETAILS CONTROLLER Application Behavior Interaction with model and view The implementation aspect of this project requires addressing several important issues. The available ontology API in Dot Net environment is OWL-Dot Net API which is not matured enough. To handle this issue, we selected JENA

3 Classes Properties Instances Content Pane that loads different pages of editor Download Ontology in different formats Figure 2. Web Interface of TODE library[21]. It provides a comprehensive set of Java classes that can be used for ontology creation, manipulation, reasoning, inferencing and support for ontology languages like RDF and OWL. Since, JENA is developed in Java; it can t be directly used in Dot Net and we need to convert JENA code into Dot Net code. The IKVM Conversion Utility[22] solves this problem by providing a console based environment for converting any Java class to Dot Net library. All business logic has been implemented in Visual C# and MS SQL Server has been used as a backend database for maintaining ontology repositories. ASP.NET and AJAX was selected for the development of view component of TODE. Telerik Tree Control[23] was also selected to further simplify the presentation of the application. Figure 3. TODE Ontology Development Process V. CREATING A PROFILE ONTOLOGY IN TODE Fig 3 shows the process of ontology development to be used in TODE. In this section, we are going to discuss how to create ontology in TODE, using a case study of Profile ontology[24], which was previously created in Protégé. The profile ontology models concepts and attributes related to a user A. Metadata Specification The first step in the creation of the ontology is to define the metadata related to ontology. Fig 4a shows how to provide metadata specification in TODE. TODE requires the ontology developer to specify ontology name, its URI and short description of the ontology. B. Scope Determination The next step in ontology creation is to identify the scope of ontology, which can be identified by considering following questions: What is the domain of ontology? For what purpose ontology will be used? Who is going to use this ontology? In case of Profile ontology, we need to consider if: Ontology is limited to employees only or any kind of user can use it What transactions a user is performing? Whether Financial and educational transactions are included or not Should the ontology cover all other aspects of a user? Once the scope of the problem is identified, it can be written in few lines. In case of profile, we can write the following statement: Users have explicit and implicit profiles for their identification, preferences, transactions, socio-economic and interaction characteristics to be handled properly.

4 a) Meta Data Specification b) Creating Concepts c) Adding Data Type Property d) Specifying Details of Data Type Properties e) Creating Instances Figure 4. Creating an Ontology in TODE C. Conceptualization The next step is to identify the concepts of ontology. The conceptualization begins with identification of nouns from the statement of scope written in previous step. These nouns serve as concepts for ontology. Furthermore, generalization and specialization of concepts are done. In profile example, we can identify following concepts from our scope: Explicit Profile, Implicit Profile, Identification Profile, Transaction Profile, Preference Profile, Socio-economic Profile, Interaction Profile, etc. The concepts of Explicit and Implicit Profiles in the profile ontology[24], can be generalized by identifying subclasses of Identification, Transaction, Preference, Socioeconomic and Interaction Profiles, which can be seen in Fig 4b. D. Define Properties In the next step, object properties among the concepts are identified. For example, in the profile ontology[24], we can identify an object property between user and profile. Also, attributes of the concepts are identified. These concepts become the data type properties. In our profile ontology, we can identify name as an attribute of identification profile, bank details for Transactions, etc. Fig 4c and 4d shows, how data type properties are specified in TODE in the data type property section. E. Create Instances In this step, the instances of the concepts are identified and created. Fig 4e shows how this will be done in TODE. VI. CONCLUSION We have developed a Dot Net based ontology editing tool TODE. The tool provides the facility to ontology developers to create ontologies in a simplified way using a well defined methodology and an easy-to-use GUI. The proposed tool is expected to incite further research and development. For example, the Dot Net community can extend this tool further by developing plug-ins, reasoners etc. fro this tool. Since, the application is designed based on

5 MVC architecture; the mobile based client for TODE can be developed and easily be plugged into TODE application. As a proof-of-concept, we show step-by-step development of our already developed profile ontology for Community Algorithm. ACKNOWLEDGEMENT We would like to thank Higher Education Commission, Pakistan for the support of this research work. We would also like to acknowledge Syed Haris Izhar, Mubasshir Ismail and Muhammad Kalim from National University of Computer and Emerging Sciences, Karachi for their participation in the implementation part of this research. REFERENCES [1] T. Berners-Lee, "Semantic Web road map," W3C Draft September 1998 [2] G. Klyne, J.J. Carroll, and B. McBride, "Resource Description Framework (RDF): Concepts and Abstract Syntax," W3C recommendation, 2004 [3] D.L. McGuinness and F. van Harmelen, "OWL Web Ontology language overview, W3C recommendation," World Wide Web Consortium, 2004 [4] N.F. Noy, M. Crubezy, R.W. Fergerson, H. Knublauch, S.W. Tu, J. Vendetti, and M.A. Musen, "Protege-2000: An open-source Ontology-development and Knowledge- Acquisition Environment," in AMIA Annu Symp, 2003, pp. 953 [5] A. Farquhar, R. Fikes, and J. Rice, "The Ontolingua Server: A tool for Collaborative Ontology construction," International Journal of Human-Computers Studies, vol(6), 1997, pp [6] J. Domingue, D. Roman, and M. Stollberg, "Web Service Modeling Ontology (WSMO)- an Ontology for Semantic Web Services," in W3C Workshop on Frameworks for Semantics in Web Services, Innsbruck, Austria, June 9-10, 2005 [7] D. Martin, M. Paolucci, S. McIlraith, M. Burstein, D. McDermott, D. McGuinness, B. Parsia, T. Payne, M. Sabou, and M. Solanki, "Bringing semantics to web services: The OWL-S approach," Lecture Notes in Computer Science, 2005, pp [8] J.C. Arpírez, O. Corcho, M. Fernández-López, and A. Gómez-Pérez, "WebODE: A Scalable Workbench for Ontological Engineering," in the First International Conference on Knowledge Capture (K-CAP), ACM, 2001, pp [9] M. Fernandez-Lopez, A. Gomez-Perez, and N. Juristo, "Methontology: from Ontological art towards Ontological Engineering," in AAAI97 Spring Symposium Series on Ontological Engineering, Stanford, USA, 1997, pp [10] Protege Plugin Library," [last accessed on March 5, 2010]; Available from: n_library. [11] L. Casely-Hayford, "A Comparative Analysis of Methodologies, Tools and Languages used for building Ontologies". 2005, CCLRC ESC [12] L. Casely-Hayford, "Environments, Methodologies and Languages for supporting Users in building a Chemical Ontology", in Faculty of Life Sciences. 2005, University of Manchester [13] O. Corcho, M. Fernández-López, and A. Gómez-Pérez, "Methodologies, Tools and Languages for building Ontologies. Where is their meeting point?," Data & Knowledge Engineering, vol(1), 2003, pp [14] A. Gomez-Perez, J. Angele, M. Fernandez-Lopez, V. Christophides, A. Stutt, and Y. Sure, "A survey on Ontology Tools", 2002, Universidad Politecnia de Madrid [15] Y. Sure, M. Erdmann, and R. Studer, "OntoEdit: Collaborative Engineering of Ontologies," in Towards the Semantic Web: Ontology-driven Knowledge Management, 2002 [16] E. Pietriga, "Isaviz: a visual environment for browsing and authoring RDF models," in Eleventh International World Wide Web Conference, 2002 [17] S.W. Altova, "Visual Semantic Web design tool for RDF and OWL", 2006 [18] T. Composer, "TOPBRAID COMPOSER 2007 Features and getting Started Guide Version 1.0", created by TopQuadrant, US, 2007 [19] J. Day-Richter, M.A. Harris, and M. Haendel, "OBO- Edit an ontology editor for biologists," Bioinformatics, vol(16), 2007, pp [20] K. Kozaki, Y. Kitamura, M. Ikeda, and R. Mizoguchi, "Hozo: An Environment for Building/Using Ontologies Based on a Fundamental Consideration of "Role" and "Relationship"," in 13th International Conference Knowledge Engineering and Knowledge Management, Spain, October 1-4, 2002, pp [21] B. McBride, "Jena: A Semantic Web toolkit," IEEE Internet Computing, 2002, pp [22] J. Frijters, "IKVM, an implementation of Java for Mono and the.net Framework," 2004 [last accessed on March 5, 2010]; Available from: [23] Rad TreeView for ASP.NET AJAX," [last accessed on March 5, 2010]; Available from: [24] M.S. Siddiqui, Z.A. Shaikh, and A.R. Memon, "Towards the development of Community Ontology," in 12th IEEE International Multi-topic Conference (INMIC), Bahria University, Karachi, Pakistan, December 2008, pp