Abstract. This paper presents the vision and results of creating a national level cross-domain ontology and ontology service infrastructure in Finland. The novelty of the infrastructure is based on two ideas. First, a system of open source core ontologies is being developed by transforming thesauri into mutually aligned lightweight ontologies, including a large top ontology that is extended by various domain specific ontologies. Second, the ONKI Ontology Server framework for publishing ontologies as ready to use services has been designed and implemented. ONKI provides legacy and other applications with ready to use functionalities for using ontologies on the HTML level by Ajax and semantic widgets. The idea is to use ONKI for creating mash-up applications in a way analogous to using Google or Yahoo Maps, but in our case external applications are mashed-up with ontology support. 1 A National Ontology Infrastructure The ambitious goal of the National Semantic Web Ontology project (FinnONTO 2003–2007) 1 [1] is to develop a semantic web infrastructure on a national level in Finland. The consortium behind the initiative—37 companies and public organizations—represents a wide spectrum of functions of the society, including libraries, health organizations, cultural institutions, government, media, and education. The project has produced a variety of scientific results, specifications, services, demonstrations, and applications: 1. Metadata standards. Nationally adapted standards for representing metadata in various application fields have been created, e.g. JHS 158 2 and [2]. 2. Core ontologies. Several core ontologies 3 have been developed in order to initiate ontology development processes in Finland.

This paper presents a method for making metadata conforming to heterogeneous schemas semantically interoperable. The idea is to make the knowledge embedded in the schema structures interoperable and explicit by transforming the schemas into a shared, event-based representation of knowledge about the real world. This enables and simplifies accurate reasoning services such as cross-domain semantic search, browsing, and recommending. A case study of transforming three different schemas and datasets is presented. An implemented knowledge-based recommender system utilizing the results in the semantic portal CULTURESAMPO was found useful in a preliminary user study.

Abstract. Vocabularies are the building blocks of the Semantic Web providing shared terminological resources for content indexing, information retrieval, data exchange, and content integration. Most semantic web applications in practical use are based on lightweight ontologies and, more recently, on the Simple Knowledge Organization System (SKOS) data model being standardized by W3C. Easy and cost-efficient publication, integration, and utilization methods of vocabulary services are therefore highly important for the proliferation of the Semantic Web. This paper presents the ONKI SKOS Server for these tasks. Using ONKI SKOS, a SKOS vocabulary or a lightweight ontology can be published on the web as ready-to-use services in a matter of minutes. The services include not only a browser for human usage, but also Web Service and AJAX interfaces for concept finding, selecting and transporting resources from the ONKI SKOS Server to connected systems. Code generation services for AJAX and Web Service APIs are provided automatically, too. ONKI SKOS services are also used for semantic query expansion in information retrieval tasks. The idea of publishing ontologies as services is analogous to Google Maps. In our case, however, vocabulary services are provided and mashed-up in applications. ONKI SKOS was published in the beginning of 2008 and is to our knowledge the first generic SKOS server of its kind. The system has been used to publish and utilize some 60 vocabularies and ontologies in the National Finnish Ontology Service ONKI www.yso.fi. 1

Content annotations in semantic cultural heritage portals commonly make spatiotemporal references to historical regions and places using names whose meanings are different in different times. For example, historical administrational regions such as countries, municipalities, and cities have been renamed, merged together, split into parts, and annexed or moved to and from other regions. Even if the names of the regions remain the same (e.g., “Germany”), the underlying regions and their relationships to other regions may change (e.g., the regional borders of “Germany ” at different times). As a result, representing and finding the right ontological meanings for historical geographical names on the semantic web creates severe problems both when annotating contents and during information retrieval. This paper presents a model for representing the meaning of changing geospatial resources. Our aim is to enable precise annotation with temporal geospatial resources and to enable semantic search and browsing using related names from other historical time periods. A simple model and metadata schema is presented for representing and maintaining geospatial changes from which an explicit time series of temporal part-of ontologies can be created automatically. The model has been applied successfully to represent the complete change history of municipalities in Finland during 1865–2007. The resulting ontology time series is used in the semantic cultural heritage portal CULTURESAMPO to support faceted semantic search of contents and to visualize historical regions on overlaying maps originating from different historical eras.

The Semantic Web is based on using ontologies for enabling semantically disambiguated data exchange between distributed systems on the web. This requires efficient means for publishing ontologies on the web to ensure the availability, sharing and acceptance of the ontologies. Support services are needed for utilizing ontologies easily and costeffectively in applications and legacy systems lacking ontology support. To address these vital needs, this paper presents the ONKI ontology service which provides ready-to-use “mash-up ” functionalities, such as semantic disambiguation, concept finding and concept fetching as readyto-use web widgets for adding ontology support to e.g. HTML forms using JavaScript. Two implementations of the ONKI Server are presented: ONKI-SKOS for ontologies presented in the Simple Knowledge Organization System (SKOS) language and ONKI-Geo for geographical ontologies with a map interface. The presented ONKI systems are operational on the web, used in the National Finnish Ontology Service. They

This paper shows how semantic web techniques can be applied to solving problems of distributed content creation, discovery, linking, aggregation, and reuse in health information portals, both from end-users ’ and content publishers’ viewpoints. As a case study, the national semantic health portal HEALTH-FINLAND is presented. It provides citizens with intelligent searching and browsing services to reliable and up-to-date health information created by various health organizations in Finland. The system is based on a shared semantic metadata schema, ontologies, and ontology services. The content includes metadata about thousands of web documents such as web pages, articles, reports, campaign information, news, services, and other information related to health.

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. 1 A Semantic Content Infrastructure The Semantic Web 1 is based on a metadata layer that describes the contents and services on the web in a machine “understandable ” way based on ontologies [5, 34]. The idea from the application viewpoint is simple: if the machine understands the contents and services it is dealing with, then better interoperability of web systems can be obtained and intelligent services provided to the end-users. This papers argues that a conceptual “semantic content infrastructure ” is needed for the semantic web, in the same way as roads are needed for traffic and transportation, power plants and electrical networks are needed for energy supply, or GSM standards and networks are needed for mobile phones and wireless communication. A solid, commonly shared infrastructure would make it much easier and cheaper for public organizations and companies to create interoperable, intelligent services on the coming semantic web. In our view, the infrastructure should be open source and its central components be maintained by the public sector in order to guarantee wide usage and interoperability across different application domains and user communities. 1

Abstract—Cultural heritage is by nature strongly interlinked, e.g. thematically and historically, but at the same time distributed in heterogeneous collections of different memory organizations at different locations. In order to provide the end-users with aggregated homogeneous views to distributed heterogeneous contents, semantic portals have been created successfully based on metadata and shared (or aligned) ontologies. This paper discusses two problems encountered in such a distributed semantic content creation environment. First, during the content creation work, how could a publisher start using shared ontologies in legacy cataloguing and annotation systems that do not support ontologies. Second, during content publication, how could a publisher re-use the aggregated content in its own legacy publication system, e.g., on the ordinary web pages of a museum or in a collection browser. As a solution, we present the ONKI Ontology Server for adding shared ontological annotation functionalities to legacy cataloguing systems in a practical, cost-efficient and lightweight way. For distributed publishing of the aggregated semantic portal services, we introduce the lightweight mash-up web widget components called “floatlets”. A major idea behind both the ONKI functionalities and floatlets is that they can be easily integrated with legacy systems on the user interface level, in the same spirit as e.g. Google Maps. I.

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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 the semantic portal “CultureSampo—Finnish Culture on the Semantic Web”.