Eetu Mäkelä

This paper presents the national level cross-domain ontology and ontology service infrastructure ONKI used in Finland. The novelty of ONKI is based on two ideas. First, the core ontologies are developed collaboratively by experts transforming thesauri into mutually aligned lightweight ontologies, based on a large top ontology that is extended by various domain specific ontologies. Second, the National Ontology Service ONKI has been implemented for publishing ontologies cost-efficiently as ready to use services. ONKI provides legacy and other applications with ready to use functionalities for using ontologies on the HTML level by Ajax and semantic widgets. ONKI has been used in various applications for creating mash-up applications in a way analogous to using Google Maps, but in our case external applications are mashed-up with ontology support for indexing and information retrieval.

Many tasks on the semantic web require the user to choose concepts from a limited vocabulary e.g. for describing an indexed resource or for use in semantic search. Semantic autocompletion interfaces offer an efficient way for concept selection. However, these interfaces usually do not expose the semantic context of the matched concepts, thereby making it hard to know if a matched concept is the right one, as well as hiding possibly more appropriate choices. Ontology browsers, on the other hand, show context but do not allow quick discovery or embedding into other applications. To lessen these problems, we present an interface combining semantic autocompletion with in-place ontological context navigation. Because required context differs between ontologies, the implementation was designed to make it easy to add different contexts and visualizations. To test the applicability of our idea and implementation the, system was tested on three ontologies with different requirements and structure.

This paper presents the semantic portal CULTURESAMPO---Finnish Culture on the Semantic Web . The portal provides memory organizations and other cultural content publishers with a national, shared semantic publication channel for heteroge- nous cultural contents. The content comes from over ten organizations and is annotated using various ontologies of the FinnONTO infrastructure. For the end-user, intel- ligent semantic search, recommendation, and visualization services for accessing and learning about cultural heritage are provided.

In this paper, we argue for a need to shift focus in semantic search from the items themselves to using them as lenses to wider topics. A system for doing this in the cultural heritage domain is presented, duplicating on the web the way exhibitions in the real world are organized. An interface for specifying such exhibitions is presented, combining a general narrative pattern with semantic autocompletion and the novel concept of domain-centric view-based search. This also solves a number of problems view-based search has previously encountered in the cultural heritage domain. Presented also are multiple visualizations for the exhibition, supporting the user in making sense of the data and in doing exploratory search.

This paper shortly presents an automatic exhibition generation interface that turns the focus of semantic search from search items to the concepts they are annotated with.

Semantic autocompletion interfaces offer an efficient way for concept selection useful in both search and annotation applications. However, these interfaces usually do not expose the semantic context of the matched concepts, thereby making it hard to know if a matched concept is the right one, as well as hiding possibly more appropriate choices. To lessen these problems, we present an in-place ontological context navigation interface to be used with semantic autocompletion.

In current Semantic Web view-based search systems views are formed by selecting properties and enumerating all their values as selections. This approach breaks down with multiple content types, such as in the cultural heritage domain, because the number of differing properties, and therefore views becomes unmanageable. We propose a novel solution termed Domain-Centric View-Based Search, in which views are created based on common property ranges and domain ontologies.

A lot of functionality is needed when an application, such as a museum cataloguing system, is extended with semantic capabilities, for example ontological indexing functionality or multi-facet search. To avoid duplicate work and to enable easy and cost-efficient integration of information systems with the Semantic Web, we propose a web widget approach. Here, data sources are combined with functionality into readyto-use software components that allow adding semantic functionality to systems with just a few lines of code. As a proof of the concept, we present a collection of general semantic web widgets and case applications that use them, such as the ontology server ONKI, the annotation editor SAHA and the culture portal CultureSampo.

Producing semantic metadata requires efficient methods, e.g., concept finding, for accessing and using ontologies. To add such functionalities to metadata applications such as cataloging systems in museums, we propose a \emphmash-up approach where ready-to-use user interface components for using specific ontologies are made available to be integrated into applications. As a proof-of-concept, we present the \emphOntology Service ONKI wich implements semantic autocompletion concept search and concept browsing for ontologies as shared mash-up components.

An event-based approach is presented for annotating events and narrative structures underlying texts and stories semantically. The idea is applied to using the Finnish national epic Kalevala for accessing related cultural contents, such as artifacts, paintings etc. in a semantic portal.

This article presents the vision and results of creating the basis for a national semantic web content infrastructure in Finland in 2003-2007. The main elements of the infrastructure are shared and open metadata schemas, core ontologies, and public ontology services. Several practical applications testing and demonstrating the usefulness of the infrastructure are overviewed in the fields of eCulture, eHealth, eGovernment, eLearning, and eCommerce.

We present ONKI ontology server, a mash-up approach for integrating ontology library services with semantic web applications. The idea of ONKI is to provide applications with ready-to-use ontology service functionalities, such as semantic autocompletion, browsing, and annotation support, at the user interface level using AJAX mash-up technologies. The system is being integrated with various semantic web applications.

This paper analyses folksonomies, an emergent web 2.0 technology. Folksonomies are found to be primarily a social dynamic phenomenon, and several key tensions are hypothesised that keep the folksonomy community vibrant. Strengths and weaknesses of folksonomies are analyzed w.r.t applicability to browsing and search, and suggestions are given on how to alleviate search problems by bringing in additional semantics into folksonomies, while trying to avoid upsetting the delicate social balances discovered.

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.

Content in semantic web portals is often projected along application specific navigational taxonomies and linked semantically. This paper presents a logic-based method and a server ONTODELLA for these tasks. We argue that logic rules between the content layer and the application layer add flexibility and better architectural separation of content and functionality. The system has been implemented and applied succesfully in several semantic portals.

This paper generalizes the idea of traditional syntactic text autocompletion onto the semantic level. The idea is to autocomplete typed text into ontological categories instead of words in a vocabulary. The idea has been implemented and its application for semantic indexing and content-based information retrieval in multi-facet search is proposed. Four operational semantic portals on the web using the implementation are presented as application cases.

This thesis explores the possibilities of using the view-based search paradigm to create intelligent search interfaces on the Semantic Web. After surveying several current semantic search techniques, the view-based search paradigm is explained, and argued to fit in a valuable niche in the field. To test the argument, OntoViews, a semantic view-based search portal creation tool was designed and implemented, and eight portals with five vastly different user interfaces were built using it. Based on the results of these experiments, this thesis argues that the paradigm, particularly as implemented in the OntoViews tool provides a strong, extensible and flexible base on which to built semantic search applications. The particular problems faced in applying view-based search for semantic interfaces are noted, along with explanations on how they were solved in the OntoViews architecture. Finally, directions and ideas for future research are presented for both the paradigm and the implementation architecture, respectively.

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.

This paper surveys the research field of semantic search, i.e. search utilizing semantic techniques or search of formally annotated semantic content. The survey identifies and discusses various prevalent research directions in se- mantic search, as well as extracts common methodology used in them.

A prototype semantic yellow page service portal is described. Our idea is to represent service offerings as events and processes in terms of ontologies. Based on versatile semantic descriptions, users can be provided with a flexible view-based search engine enhanced with semantic text autocompletion.

This paper argues for using the multi-facet search paradigm as a basis in information retrieval on the Semantic Web. To support the argument, two user interfaces for extant semantic web portals based on the concept of viewhierarchies are presented. The interfaces described reveal and contrast how the view-based paradigm can be applied to support both browsing and searching strategies in information retrieval in applications using different domain and annotation ontologies. New semantics-based user interface elements complementing the basic paradigm are also discussed.

This paper describes the ongoing work of IWebS (Intelligent Web Services) project, which studies the possibilities of the Semantic Web technology in creating a yellow page directory service for end-users. We propose an ontology-based mechanism for both advertising and finding the services. The essential parts of the system are ontologies for describing and storing service advertisements, a semantic service finder for the enduser, and a semantic service annotation editor for service providers.

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-user s 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. ONTOVIEWS is presented from the view points 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 ONTOVIEWS to a deployed semantic web portal is discussed.

Museum collections contain large amounts of data and semantically rich, mutually interrelated metadata in heterogeneous databases. The publication of museum collections on the web is therefore a very promising application domain for semantic web techniques. We present a semantic web portal called MUSEUMFINLAND - Finnish Museums on the Semantic Web , that contains some 4,000 cultural artifacts from the collections of three museums using three different database schemas and database systems. The system is based on seven RDF(S) ontologies consisting of some 10,000 classes and individuals.

This paper presents a deployed semantic web application in the cultural domain: the semantic portal MUSEUMFINLAND. It is a demonstration of a community portal and a publication channel by which heterogeneous collection database contents of different museums can be published on the Semantic Web. By semantic web techniques, 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.

This paper presents a semantic portal, MuseumFinland, for publishing heterogeneous museum collections on the Semantic Web. The application is presented from the viewpoints of the end-user and the museums providing the contents. By semantic Web techniques, it is possible to make collections semantically interoperable and provide museum visitors with intelligent content-based search and browsing services to the global collection base. By using the MuseumFinland approach, the museums with their semantically rich and interrelated collection content can create consolidated semantic collection portals together on the Web.

This paper presents the semantic portal MUSEUMFINLAND for publishing 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 semantic web techniques, it is possible to make collections semantically interoparable and provide the museum visitors with inntelligent content-based search and browsing services to the global collection base.