Visualizing and Navigating Large Multimodal Semantic Webs Weng Onn Kow and Dickson Lukose (Artificial Intelligence Centre, MIMOS Berhad, Malaysia {kwonn | dickson.lukose}@mimos.my) Abstract: A graph is the most common method of visualizing a semantic web. However, when dealing with large and complex semantic webs, existing systems face challenges such as slow loading times and too much information being displayed on the screen. This paper introduces a Multimodal Semantic Browser (MMSB) that allows users to visualize and navigate through semantic webs with millions of triples. In addition, the Browser also recognizes the type of content that the user has selected and chooses the best modality and application to display that content in addition to a graph display. Keywords: Ontology Visualization, Graph Layout, Service Oriented Architecture, Semantic Web Categories: H.5, I.2.4 1 Introduction Many current applications of the Resource Description Framework (RDF) [RDF] and Semantic Web technologies are as a way to represent knowledge so that computers can ‘understand’ and manipulate knowledge for intelligent reasoning. In his survey paper on the deployment of the Semantic Web technologies, Cardoso found that 69.9% of the participants used ontologies to share common understanding of the structure of information, so that models can be understood by humans and computers [Cardoso 07]. However, the trade-off of modeling knowledge this way is that the knowledge base developed becomes too complex for a human to visualize and comprehend. A graph is a popular and elegant way of visualizing an RDF triple. By showing all triples of a concept in a specific format, we have a good method for displaying everything in the knowledge base about that concept in a single screen. Navigating from one concept to another is usually done by selecting one of the nodes linked to the main or focus concept. This new node then becomes the focus and all the triples belonging to it is displayed. According to Katifori [Katifori], displaying information this way is called the focus + context method. This method of visualization is used in, TGVizTab [TGVizTab], a popular plug-in for Protégé [Protégé], and the RKB Explorer [Glaser] developed by the University of Southampton. The main advantage of using such a visualization method is that it keeps things in a small and manageable display regardless of the size of the knowledge base. Other ways of visualizing a knowledge base as categorized by Katifori are: Proceedings of I-KNOW 2010 1-3 September 2010, Graz, Austria 175