Samppa Saarela

MuseumFinland-Finnish museums on the semantic web

This article presents the semantic portal MuseumFinland for publishing heterogeneous museum collections on the Semantic Web. It is shown how museums with their semantically rich and interrelated collection content can create a large, consolidated semantic collection portal together on the web. By sharing a set of ontologies, it is possible to make collections semantically interoperable, and provide the museum visitors with intelligent content-based search and browsing services to the global collection base. The architecture underlying MuseumFinland separates generic search and browsing services from the underlying application dependent schemas and metadata by a layer of logical rules. As a result, the portal creation framework and software developed has been applied successfully to other domains as well. MuseumFinland got the Semantic Web Challence Award (second prize) in 2004.

Application of Ontology Techniques to View-Based Semantic Search and Browsing

We show how the benefits of the view-based search method, developed within the information retrieval community, can be extended with ontology-based search, developed within the Semantic Web community, and with semantic recommendations. As a proof of the concept, we have implemented an ontology- and view-based search engine and recommendation system Ontogator for RDF(S) repositories. Ontogator is innovative in two ways. Firstly, the RDFS-based ontologies used for annotating metadata are used in the user interface to facilitate view-based information retrieval. The views provide the user with an overview of the repository contents and a vocabulary for expressing search queries. Secondly, a semantic browsing function is provided by a recommender system. This system enriches instance level metadata by ontologies and provides the user with links to semantically related relevant resources. The semantic linkage is specified in terms of logical rules. To illustrate and discuss the ideas, a deployed application of Ontogator to a photo repository of the Helsinki University Museum is presented.

Ontoviews: a tool for creating semantic web portals

This paper presents a semantic web portal tool OntoViews for publishing RDF content on the web. OntoViews provides the portal designer with a content-based search engine server, Ontogator, and a link recommendation system server, Ontodella. The user interface is created by combining these servers with the Apache Cocoon framework. From the end-users viewpoint, the key idea of OntoViews is to combine the multi-facet search paradigm, developed within the information retrieval research community, with semantic web RDFS ontologies, and extend the search service with a semantic browsing facility based on ontological reasoning. Onto Views is presented from the viewpoints of the end-user, architecture, and implementation. The implementation described is modular, easily modified and extended, and provides a good practical basis for creating semantic portals on the web. As a proof of concept, application of Onto Views to a deployed semantic web portal is discussed.

Ontogator — a semantic view-based search engine service for web applications

View-based search provides a promising paradigm for formulating complex semantic queries and representing results on the Semantic Web. A challenge for the application of the paradigm is the complexity of providing view-based search services through application programming interfaces (API) and web services. This paper presents a solution on how semantic view-based search can be provided efficiently through an API or as web service to external applications. The approach has been implemented as the open source tool Ontogator, that has been applied successfully in several practical semantic portals on the web.