Publications of Eero Hyvönen

This paper presents first results of a new, ninth application perspective for the semantic portal WarSampo - Finnish WW2 on the Semantic Web, based on a database of ca. 4450 Finnish prisoners of war in the Soviet Union. Our key idea is to reassemble the life of each prisoner of war by using Linked Data, based on information about the person in different data sources. Using the enriched aggregated data, a biographical global home page for each prisoner of war can be created, that is more complete than information in individual data sources. The application perspective is targeted to researchers of military history, to study and analyze the data in order to form new research questions or hypotheses, as well as to public in the large looking for information e.g., about their relatives that were captured as prisoners of war. Employing the faceted search of the application perspective, prosopographical research on subgroups of prisoners is possible.

The vision behind the Semantic Wed is to build a global Web of Data (Giant Global Graph, GGG) for machines to use: based on this an interoperable and intelligent transnational WWW for humans can be created cost-efficiently. This keynote presentation for the DCMI 2001 conference addresses this grand challenge on a national level, as in practice much of the data available are often related to each other within national cultures, borders, organizations, and are represented using national languages, metadata models, vocabularies, and local conventions. This presentation overviews and discusses the vision and lessons learned in Finland on developing and deploying a cross-domain national ontology service infrastructure and Linked Open Data (LOD) publishing framework, extending the classic 5-star model to a 7-star model for better data re-usability (6. star) and quality (7. star). To test and demonstrate the infrastructure, a series of semantic portals and LOD services have been created using the Sampo model that has evolved gradually in 2002--2021 through lessons learned when developing and publishing the Sampo series of systems, including MuseumFinland (2004), HealthFinland (2009), CultureSampo (2009), BookSampo (2011), WarSampo (2015), BiographySampo (2018), NameSampo (2019), WarWictimSampo (2019), Mapping Manuscript Migrations (2020), AcademySampo (2021), as well as FindSampo, Law\-Sampo, and ParliamentSampo underway. These systems cover a wide range of application domains and have attracted up to millions of users on the Semantic Web depending on the application, suggesting feasibility of the proposed model. This work shows a shift of focus in research on semantic portals from data aggregation and exploration systems (1. generation systems) to systems supporting research with data analytic tools (2. generation systems), and finally to automatic knowledge discovery and Artificial Intelligence (3. generation systems).

This paper shows how named entity extraction and networkanalysis can be used to examine biographies individually and in groupsto aid historians in biographical and prosopographical research. For this purpose a reference network of 13 100 biographies in the collections ofthe Biographical Centre of the Finnish Literature Society was created, based on links between the biographies as well as automatically extracted named entities found in the texts. The data was published in a SPARQL endpoint as a Linked Data knowledge graph on top of which network analytic tools were created and analysis were done showing the usefulness of the approach in Digital Humanities. The reference graph has been utilized for network analysis to examine egocentric networks of individual persons as well as networks among groups of people in prosopography. The data and tools presented are in use since autumn 2018 in the semantic portal BiographySampo that has had tens of thousands of users.

Manuscripts are a crucial form of evidence for research into all aspects of premodern European history and culture, and there are numerous databases devoted to describing them in detail. This descriptive information, however, is typically available only in separate data silos based on incompatible data models and user interfaces. As a result, it has been difficult to study manuscripts comprehensively across these various platforms. To address this challenge, a team of manuscript scholars and computer scientists worked to create “Mapping Manuscript Migrations” (MMM), a semantic portal, and a Linked Open Data service. MMM stands as a successful proof of concept for integrating distinct manuscript datasets into a shared platform for research and discovery with the potential for future expansion. This paper will discuss the major products of the MMM project: a unified data model, a repeatable data transformation pipeline, a Linked Open Data knowledge graph, and a Semantic Web portal. It will also examine the crucial importance of an iterative process of multidisciplinary collaboration embedded throughout the project, enabling humanities researchers to shape the development of a digital platform and tools, while also enabling the same researchers to ask more sophisticated and comprehensive research questions of the aggregated data.

This paper presents a new knowledge-based approach for finding serendipitous semantic relations between resources in a knowledge graph. The idea is to characterize the notion of “interesting connection” in terms of generic ontological explanation patterns that are applied to an underlying linked data repository to instantiate connections. In this way, 1) semantically uninteresting connections can be ruled out effectively, and 2) natural language explanations about the connections can be created for the end-user. The idea has been implemented and tested based on a knowledge graph of biographical data extracted from the life stories of 13,144 prominent historical persons in Finland, enriched by data linking to collection databases of museums, libraries, and archives. The demonstrator is in use as part of the BiographySampo portal of interlinked biographies.

The Second World War (WW2) is arguably the most devastating catastrophe of human history, a topic of great interest to not only researchers but the general public. However, data about the Second World War is heterogeneous and distributed in various organizations and countries making it hard to utilize. In order to create aggregated global views of the war, a shared ontology and data infrastructure is needed to harmonize information in various data silos. This makes it possible to share data between publishers and application developers, to support data analysis in Digital Humanities research, and to develop data-driven intelligent applications. As a first step towards these goals, this article presents the WarSampo knowledge graph (KG), a shared semantic infrastructure, and a Linked Open Data (LOD) service for publishing data about WW2, with a focus on Finnish military history. The shared semantic infrastructure is based on the idea of representing war as a spatio-temporal sequence of events that soldiers, military units, and other actors participate in. The used metadata schema is an extension of CIDOC CRM, supplemented by various military historical domain ontologies. With an infrastructure containing shared ontologies, maintaining the interlinked data brings upon new challenges, as one change in an ontology can propagate across several datasets that use it. To support sustainability, a repeatable automatic data transformation and linking pipeline has been created for rebuilding the whole WarSampo KG from the individual source datasets. The WarSampo KG is hosted on a data service based on W3C Semantic Web standards and best practices, including content negotiation, SPARQL API, download, automatic documentation, and other services supporting the reuse of the data. The WarSampo KG, a part of the international LOD Cloud and totalling ca. 14 million triples, is in use in nine end-user application views of the WarSampo portal, which has had over 400 000 end users since its opening in 2015.

Semantic data integration from heterogeneous, distributed data silos enables Digital Humanities research and application development employing a larger, mutually enriched and interlinked knowledge graph. However, data integration is challenging, involving aligning the data models and reconciling the concepts and named entities, such as persons and places. This paper presents a record linkage process to reconcile person references in different military historical person registers with structured metadata. The information about persons is aggregated into a single knowledge graph. The process was applied to reconcile three person registers of the popular semantic portal WarSampo -- Finnish World War 2 on the Semantic Web . The registers contain detailed information about some 100,000 people and are individually maintained by domain experts. Thus, the integration process needs to be automatic and adaptable to changes in the registers. An evaluation of the record linkage results is promising and provides some insight into military person register reconciliation in general.

Governments publish legislation and case law widely in print and on the Web. Such legal information is provided for human consumption, but the information is usually not available as data for algorithmic analysis and applications to use. However, this would be beneficial in many use cases, such as building more intelligent juridical online services and conducting research into legislation and legal practice. To address these needs, this Chapter presents Semantic Finlex, a national in-use data resource and service for publishing Finnish legislation and related case law as Linked Open Data for legal applications to use. The system transforms and interlinks on a regular basis data from the legacy legal database Finlex of the Ministry of Justice into Linked Open Data, based on the European standards ECLI and ELI. The published data is hosted on the 7-star Linked Data Finland service and SPARQL endpoint with a variety of related services available that ease data re-use. Rich Internet Applications using SPARQL for data access are presented as application demonstrators of the data service. In addition, this Chapter presents methods and tools under development to automatically annotate legal texts and to anonymize case law documents prior to their publication on the Web. Anonymization is necessary due to issues of data protection and privacy, and annotation is needed for semantic search and interlinking the documents. The automated approaches could significantly speed up the process and minimize costs of publishing legal documents as Linked Open Data.

WarSampo Knowledge Graph includes harmonized data of different kinds concerning the Second World War in Finland, separated in different subgraphs representing events, actors, places, photographs, and other aspects and documentation of the war. The data covers the Winter War 1939-1940 against the Soviet attack, the Continuation War 1941-1944 where the occupied areas of the Winter War were temporarily regained, and the Lapland War 1944-1945, where the Finns pushed the German troops away from Lapland.

Historical datasets often impose the need to study groups of people based on occupation or social status. This paper presents first results in creating an ontology of historical Finnish occupations, AMMO, that enables selection of groups of people based on their occupation, occupational groups, or socioeconomic class. AMMO is linked to the international historical occupation classification HISCO and to a modern Finnish occupational classification for interoperability. AMMO will be used as a component in two semantic portals for Finnish war history.

This paper introduces AMMO Ontology of Finnish Historical Occupations. AMMO is based on thousands of occupation labels extracted from three Finnish military historical datasets of the early 20th century: the first consists of the ca. 40 000 war-related death records around the time of the Finnish Civil War (1914–1922); the second consists of the ca. 95 000 death records of Finnish soldiers in the Winter War and Continuation War (1939–1944); the third contains the ca. 4500 records of Finnish prisoners of war in the Soviet Union during the WW2. Our goal from a Digital Humanities perspective is to use AMMO to study military history and these datasets based on the occupation and social status of the soldiers. AMMO will also be used as a component for faceted search and semantic recommendation in two semantic portals for Finnish military history. AMMO is aligned with the international historical occupation classification HISCO and with a modern Finnish occupational classification for international and national interoperability. The ontology is published as Linked Open Data in an ontology service.

This paper shows how faceted search on biographical data can be utilized as a flexible basis for filtering target groups of people and, in particular, how generic data analysis and visualization tools can then be applied for solving prosopographical research questions based on the filtered data. This idea is demonstrated and evaluated in practice by presenting two application case studies: 1) linked data extracted from a printed registry of over 10 000 alumni (1867–1992) of the prominent Finnish high school Norssi, and 2) a knowledge graph extracted from 13 000 short biographies of significant Finnish people (from 3rd century to present times) in the National Biography of Finland. In both cases, the data is enriched by linking their entities with several other external datasets.

Biographies make a promising application case of Linked Data: they can be used, e.g., as a basis for Digital Humanities research in prosopography and as a key data and linking resource in semantic Cultural Heritage (CH) portals. In both use cases, a semantic data model for harmonizing and interlinking heterogeneous data from different sources is needed. This paper presents such a data model, Bio CRM, with the following key ideas: 1) The model is a domain specific extension of CIDOC CRM, making it applicable to not only biographical data but to other CH data, too. 2) The model makes a distinction between enduring unary roles of actors, their enduring binary relationships, and perduing events, where the participants can take different roles modeled as a role concept hierarchy. 3) The model can be used as a basis for semantic data validation and enrichment by reasoning. 4) The enriched data conforming to Bio CRM is targeted to be used by SPARQL queries in a flexible ways using a hierarchy of roles in which participants can be involved in events.

This paper presents a series of projects where one of the main sources for toponomastic research in Finland, the corpora of place names in the Names Archive database of the Institute for the Languages of Finland, was digitized and how the resulting database was converted, enriched and published as Linked Open Data using a data processing pipeline. Utilizing the Linked Data infrastructure and various external data sources, a modern full-stack web application, NameSampo, was created in collaboration between toponomastic researchers and computer scientists for searching, analyzing, and visualizing digital toponomastic data sources.

Biografiasampo-järjestelmä käynnistää uuden aikakauden elämäkertakokoelmien julkaisemisessa ja käyttämisessä verkossa. Järjestelmän ydinaineistona on Kansallisbiografia ja muut Suomalaisen Kirjallisuuden Seuran (SKS) ja tieteellisten seurojen toimittamat pienoiselämäkerrat, yhteensä 13 100 elämäntarinaa, joita on kirjoittanut 900 suomalaista tutkijaa. Biografiasammon innovaationa on luoda kieliteknologian, tekoälyn ja semanttisen webin teknologioiden avulla elämäkertojen teksteistä ja niihin eri lähteissä liittyvistä tiedoista tietämysverkko (knowledge graph) ja kansallinen tietoinfrastruktuuri, joka koostuu miljoonista tietojen välisistä yhteyksistä. Tietämysverkko on julkaistu linkitetyn datan palvelussa, jonka varaan on toteutettu seitsemästä sovellusnäkymästä koostuva älykäs, kaikille avoin ja maksuton verkkopalvelu biografiasampo.fi kansalaisten ja digitaalisten ihmistieteiden tutkijoiden käytettäväksi.

Between 1500 and 1800, a revolution in postal communication allowed ordinary men and women to scatter letters across and beyond Europe. This exchange helped knit together what contemporaries called the respublica litteraria, Republic of Letters, a knowledge-based civil society, crucial to that era’s intellectual breakthroughs, and formative of many modern European values and institutions. To enable effective Digital Humanities research on the epistolary data distributed in different countries and collections, metadata about the letters have been aggregated, harmonised, and provided for the research community through the Early Modern Letters Online (EMLO) service. This paper discusses the idea and benefits of using Linked Data as a basis for the next digital framework of EMLO, and presents experiences of a first demonstrational implementation of such a system.

This paper presents the vision of publishing and utilizing textual biographies as Linked (Open) Data on the Semantic Web. As a case study, we publish the live stories of the National Biography of Finland, created by the Finnish Literature Society, as semantic, i.e., machine “understandable” metadata in a SPARQL endpoint using the Linked Data Finland (LDF.fi) service. On top of the data service various Digital Humanities applications are built. The applications include searching and studying individual personal histories as well as historical research of groups of persons using methods of prosopography. The biographical data is enriched by extracting events from unstructured and semi-structured texts, and by linking entities internally and to external data sources. A faceted semantic search engine is provided for filtering groups of people from the data for prosopographical research. An extension of the event-based CIDOC CRM ontology is used as the underlying data model, where lives are seen as chains of interlinked events populated from the data of the biographies and additional data sources, such as museum collections, library databases, and archives.

One of the great promises of Linked Data and the Semantic Web standards is to provide a shared data infrastructure into which more and more data can be imported and aligned, forming a sustainable, ever growing knowledge graph or linked data cloud, Web of Data. This paper studies and evaluates this idea in the context of the WarSampo Linked Data cloud, providing an infrastructure for data related to the Second World War in Finland. As a case study, a new database of prisoners of war with related contents is transformed into linked data and integrated into WarSampo. Lessons learned are discussed in relation to using traditional data publishing approaches.

War history of the Second World War (WW2), humankind’s largest disaster, is of great interest to both laymen and researchers. Most of us have ancestors and relatives who participated in the war, and in the worst case got killed. Researchers are eager to find out what actually happened then, and even more importantly why, so that future wars could perhaps be prevented. The darkest data of war history are casualty records—from such data we could perhaps learn most about the war. This paper presents a model and system for representing death records as linked data, so that 1) citizens could find out more easily what happened to their relatives during WW2 and 2) digital humanities (DH) researchers could (re)use the data easily for research.

Advanced automation is needed in future mobile networks to provide adequate service quality economically and with high reliability. In this paper, a system is presented that takes into account the network context, analyses uncertain information, and infers network configurations by means of probabilistic reasoning. The system introduced in this paper is an experimental platform integrating a mobile network simulator, a Markov Logic Network (MLN) model, and an OWL 2 ontology into a runtime environment that can be monitored via a Resource Description Framework (RDF) -based user interface. In this approach, the OWL ontology contains a semantic representation of the relevant concepts, and the MLN model evaluates elements of uncertain information. Experiments based on a prototype implementation demonstrate the value of semantic modelling and probabilistic reasoning in network status characterization, optimization, and visualization.

The CIDOC-CRM standard indicates that common events, actors, places and timeframes are important in linking together cultural material, and provides a framework for describing them. However, merely describing entities in this way in two datasets does not yet interlink them. To do that, the identities of instances still need to be either reconciled, or be based on a shared vocabulary. The WW1LOD dataset presented in this paper was created to facilitate both of these approaches for collections dealing with the First World War. For this purpose, the dataset includes events, places, agents, times, keywords, and themes related to the war, based on over ten different authoritative data sources from providers such as the Imperial War Museum. The content is harmonized into RDF, and published as a Linked Open Data service. While generally basing on CIDOC-CRM, some modeling choices used also deviate from it where our experience dictated such. In the article, these deviations are discussed in the hope that they may serve as examples where CIDOC-CRM itself may warrant further examination. As a demonstration of use, the dataset and online service have been used to create a contextual reader application that is able link together and pull in information related to WW1 from e.g. 1914–1918 Online, Wikipedia, WW1 Discovery, Europeana and the Digital Public Library of America.

This paper presents an application for studying the death records of WW2 casualties from a prosopograhical perspective, provided by the various local military cemeteries where the dead were buried. The idea is to provide the end user with a global visual map view on the places in which the casualties were buried as well as with a local historical perspective on what happened to the casualties that lay within a particular cemetery of a village or town. Plenty of data exists about the Second World War (WW2), but the data is typically archived in unconnected, isolated silos in different organizations. This makes it difficult to track down, visualize, and study information that is contained within multiple distinct datasets. In our work, this problem is solved using aggregated Linked Open Data provided by the WarSampo Data Service and SPARQL endpoint.

This paper describes the ontology model and published datasets of a digitized biographical person register. The applied ontology model is designed to represent people via their enduring roles and perduring lifetime events. The model is designed to support 1) prosopographical Digital Humanities research, 2) linking to resources in semantic Cultural Heritage portals, and 3) semantic data validation and enrichment by using SPARQL queries. The linked data approach enables to enrich a person s biography by interlinking it with space and time related biographical events, persons relating by social contacts or family relations, historical events, and personal achievements.

This paper presents a model for representing historical military personnel and army units, based on large datasets about World War II in Finland. The model is in use in WarSampo data service and semantic portal, which has had tens of thousands of distinct visitors. A key challenge is how to represent ontological changes, since the ranks and units of military personnel, as well as the names and structures of army units change rapidly in wars. This leads to serious problems in both search as well as data linking due to ambiguity and homonymy of names. In our solution, actors are represented in terms of the events they participated in, which facilitates disambiguation of personnel and units in different spatio-temporal contexts. The linked data in the WarSampo Linked Open Data cloud and service has ca. 9 million triples, including actor datasets of ca. 100 000 soldiers and ca. 16 100 army units. To test the model in practice, an application for semantic search and recommending based on data linking was created, where the spatio-temporal life stories of individual soldiers can be reassembled dynamically by linking data from different datasets. An evaluation is presented showing promising results in terms of linking precision.

The article overviews the system WarSampo – Finnish World War 2 on the Semantic Web, the winner of the LODLAM Challenge 2017 Open Data Prize on June 29 in Venice, Italy.

This paper presents the idea to enrich printed biographical person registers with linked data related to events that took place after the register was published. By transforming printed historical documents into structured data, semantic search to written texts can be provided for the reader. Even more importantly, life stories of historical persons can be extended based on data linking by extracting semantic structures from printed texts, and by combining this data with external datasets and data services. Such linking provides an enriched context for prosopographical research on people in the register, as well as an enhanced reading experience for anyone interested in reading the biographies. As a concrete case study, a register 1867–1992 of over 10 000 alumni of the prominent Finnish high school “Norssi” was transformed into RDF, was enriched by data linking, was published as a linked data service, and is provided to end users via a faceted search engine and browser for studying lives of historical persons and for prosopographical research.

This paper presents an automatic annotation tool AATOS for providing documents with semantic annotations. The tool links entities found from the texts to ontologies defined by the user. The application is highly configurable and can be used with different natural language Finnish texts. The application was developed as a part of WarSampo and Semantic Finlex projects and tested using Kansa Taisteli magazine articles and consolidated Finnish legislation of Semantic Finlex. The quality of the automatic annotation was evaluated by measuring precision and recall against existing manual annotations. The results showed that the quality of the input text, as well as the selection and configuration of the ontologies impacted the results.

This paper discusses the challenges of applying named entity linking in a rich, complex domain – specifically, the linking of 1) military units, 2) places and 3) people in the context of rich Second World War data. Multiple sub-scenarios are discussed in detail through concrete evaluations, analyzing the problems faced, and the solutions developed. A key contribution of this work is to highlight the heterogeneity of problems and approaches needed even inside a single domain, depending on both the source data as well as the target authority.

A major challenge in publishing linked Cultural Heritage (CH) collections on the web is interoperability. This is due to the heterogeneity of CH contents and the distributed content creation model where publishers focus on their own data with little consideration on the others’ data. As a solution approach, the “Sampo” model is presented based on using domain independent modeling standards, on a model for aligning metadata models, and on sharing domain ontologies for populating the matadata models. The harmonized data is published for machines as a linked data service, to be used by applications for human users. To illustrate and evaluate the model, three online systems on the Web, Culture- Sampo, BookSampo, and WarSampo are presented.

Data about wars is typically heterogeneous, distributed in the data silos of the fighting parties, multilingual, and often controversial depending on the political point of view. It is therefore hard for the historians to get a global picture of what has actually happened, to whom, where, when, and how. We argue that Semantic Web and Linked Data technologies are a very promising approach for modeling, harmonizing, and aggregating data about war history. Our goal is to make it possible, for both historians and laymen, to study history in a contextualized way where linked datasets enrich each other. The paper presents the in-use WarSampo 1 system, where massive collections of heterogeneous data about the (Finnish) history of the Second World War are harmonized using an event-based approach, and provided as a Linked Open Data service for applications to use. As a use case, a semantic portal WarSampo providing six different perspectives to the war based on events is presented.

CORE is a contextual reader application intended to improve user close reading experience, particularly with regard to material in an unfamiliar domain. CORE works by utilizing Linked Data reference vocabularies and datasets to identify entities in any PDF file or web page. For each discovered entity, pertinent information such as short descriptions, pictures, or maps are sourced and presented on a mouse-over, to allow users to familiarize themselves with any unfamiliar concepts, places, etc in the texts they are reading. If further information is needed, an entity can be clicked to open a full context pane, which supports deeper contextualization (also visually, e.g. by displaying interactive timelines or maps). Here, CORE also facilitates serendipitous discovery of further related knowledge, by being able to bring in and suggest related resources from various repositories. Clicking on any such resource loads it into the contextual reader for endless further browsing.

War history of the Second World War (WW2), humankind s largest disaster, is of great interest to both laymen and researchers. Most of us have ancestors and relatives who participated in the war, and in the worst case got killed. Researchers are eager to find out what actually happened then, and even more importantly why, so that future wars could perhaps be prevented. The darkest data of war history are casualty records---from such data we could perhaps learn most about the war. This paper presents a model and system for representing death records as linked data, so that 1) citizens could find out more easily what happened to their relatives during WW2 and 2) digital humanities (DH) researchers could (re)use the data easily for research.

This paper presents a new Linked Open Data brokering service model HIPLA for using and maintaining historical place gazetteers and maps based on distributed SPARQL endpoints. The model introduces several novelties: First, the service facilitates collaborative maintenance of geo-ontologies and maps in real time as a side effect of annotating contents in legacy cataloging systems. The idea is to support a collaborative ecosystem of curators that creates and maintains data about historical places and maps in a sustainable way. Second, in order to foster understanding of historical places, the places can be provided on both modern and historical maps, and with additional contextual Linked Data attached. Third, since data about historical places is typically maintained by different authorities and in different countries, the service can be used and extended in a federated fashion, by including new distributed SPARQL endpoints (or other web services with a suitable API) into the system. To test and demonstrate the model, we created the first prototype implementation Hipla.fi of the HIPLA model. Hipla.fi is based on four Finnish datasets in SPARQL endpoints totaling some 840,000 geocoded places on 450 historical maps from two atlas series aligned on modern maps, and on the Getty Thesaurus of Geographic Names (TGN) SPARQL endpoint in the US. As a first application, a part of the Hipla.fi data service has been applied in creating a 5 million triple semantic portal of historical Second World War data with tens of thousands of end users.

The faceted search paradigm is widely used in web applications, and there are various tools available for implementing it on the server side. In contrast, this paper presents an HTML based component tool on the client side that can be plugged on virtually any public SPARQL endpoint on the web, using only SPARQL API for data retrieval. To test and demonstrate the idea and the tool, application of the tool in a large in-use semantic portal is presented.

This paper presents the WarSampo system for publishing collections of heterogeneous, distributed data about the Second World War on the Semantic Web. WarSampo is based on harmonizing massive datasets using event-based modeling, which makes it possible to enrich datasets semantically with each others’ contents. WarSampo has two components: First, a Linked Open Data (LOD) service WarSampo Data for Digital Humanities (DH) research and for creating applications related to war history. Second, a semanticWarSampo Portal has been created to test and demonstrate the usability of the data service. The WarSampo Portal allows both historians and laymen to study war history and destinies of their family members in the war from different interlinked perspectives. Published in November 2015, theWarSampo Portal had some 20,000 distinct visitors during the first three days, showing that the public has a great interest in this kind of applications.

This paper initiates and fosters work on publishing Linked Open Data about the Second World War. It is argued that the heterogeneous, distributed data about the international world war history makes a promising use case for semantic technologies. We hope that by making war data openly available we can learn from the past and promote peace.

This paper introduces the idea of applying crowdsourcing to evolving ontology services; the goal is to facilitate collaborative maintenance of ontologies in real time as a side effect of annotating contents in legacy cataloging systems. The idea is being implemented in the use case of creating and managing a national level gazetteer of historical places in Finland.

Current mobile tourist guide systems are developed and used in separate data silos: each system and vendor tends to use its own proprietary, closed formats for representing tours and point of interest (POI) content. As a result, tour data cannot be enriched from other providers’ tour and POI repositories, or from other external data sources — even when such data were publicly available by, e.g., cities willing to promote tourism. This paper argues, that an open shared RDF-based tour vocabulary is needed to address these problems, and introduces such a model, TourRDF, extending the earlier TourML schema into the era of Linked Data. As a test and an evaluation of the approach, a case study based on data about the Unesco World Heritage site Suomenlinna fortress is presented.

This paper argues, by presenting a case study and a demonstration on the web, that biographies make a promising application case of Linked Data: the reading experience can be enhanced by enriching the biographies with additional life time events, by proving the user with a spatio-temporal context for reading, and by linking the text to additional contents in related datasets.

The Finnish Ontology Library Service ONKI was published as a living laboratory prototype for public use in 2008. Its idea is to support content indexers and ontology developers via a browser interface and machine APIs. ONKI has been well-accepted, but being a prototype maintained by the ending research project FinnONTO (2003–2012), a more sustainable service was needed, supported by permanent governmental funding. To achieve this, ONKI was deployed and is being further developed by the National Library of Finland into a new national vocabulary service Finto. We discuss challenges in the deployment of ONKI into Finto and lessons learned during the transition process.

The idea of Linked Data is to aggregate, harmonize, integrate, enrich, and publish data for re-use on the Web in a cost-efficient way using Semantic Web technologies. We concern two major hindrances for re-using Linked Data: It is often difficult for a re-user to 1) understand the characteristics of the dataset and 2) evaluate the quality the data for the intended purpose. This paper introduces the “Linked Data Finland” platform LDF.fi addressing these issues. We extend the famous 5-star model of Tim Berners-Lee, with the sixth star for providing the dataset with a schema that explains the dataset, and the seventh star for validating the data against the schema. LDF.fi also automates data publishing and provides data curation tools. The first prototype of the platform is available on the web as a service, hosting tens of datasets and supporting several applications.

SPARQL SAHA is a linked data editor and browser that can be used as a service, targeting any available SPARQL endpoint. Besides being available as a web service, the primary differentiating features of the tool are its configurability to match the underlying data, and the fact that the usability of its user interface has been verified by dozens of non-experts using the tool in multiple multi-year projects.

This paper presents first results of a use case of Linked Data for eScience, where 0.5 million rows of bird migration observations over 30 years time span are linked with 0.1 million rows of related weather observations and a bird species ontology. Using the enriched linked data biology researchers at the Finnish Museum of Natural History will be able to investigate temporal changes in bird biodiversity and how weather conditions affect bird migration. To support data exploration, the data is published in a SPARQL endpoint service using the RDF Data Cube model, on which semantic search and visualization tools are built.

Using online primary sources is both rewarding and challenging for users. Improving subject access is essential as these sources become increasingly important in educational curricula. A user needs assessment with humanities users showed improving findability and context for historical subjects were major needs. Linked Data can help by linking related concepts in the sources using specialized vocabularies, enriching them with outside resources, and enabling semantic services that empower users. This article discusses a project to enhance subject access in an online World War I collection by deep linking historical data on the civilian experience in occupied Belgium and France.

The BookSampo dataset provides information as linked data on fiction literature published in Finland going back to the 15th century, along with rich descriptions of both their content and context. The dataset contains data on nearly 400,000 subjects, including literary works, authors, book covers, reviews, awards, images, and movies, over 3 million triples in total. The data has been applied as the basis of the BookSampo portal in public use in Finland, and is aligned with the cross-domain cultural heritage contents and ontologies of CultureSampo, another in-use semantic portal. The data has been used to answer complex questions, such as what topics should one write about, if one wants to get a literary award (based on statistics). The metadata was transformed into RDF from legacy library databases, then enriched manually by dozens of librarians in a Web 2.0 fashion in Finnish public libraries, and is constantly updated at a rate of some new 90,000 triples monthly.

The idea of opening data on the Web as Linked Data (LD) is widely adopted in areas such as public government, science, libraries, and cultural heritage. The key idea is to harmonize, integrate, enrich, and re-use existing data repositories in a cost-efficient way via standard APIs in novel applications. This paper concerns two major hindrances for re-using LD: It is often difficult for a re-user to understand the 1) characteristics of the dataset and 2) evaluate the quality of the data for her intended purpose. This paper introduces the “Linked Data Finland” publishing platform LDF.fi addressing these issues. In order to enhance and promote reusability, we propose extending the famous 5-star model of Tim Berners-Lee into a 7-star model: The sixth star requires that the dataset is defined and explained in terms of explicit schemas. Explicit schemas make it possible to explain the re-user the intended characteristics of the data by, e.g., documentation about the schemas, and how the schemas (vocabularies) are actually used in the given dataset. The seventh star is given, if the data has also been validated w.r.t. the schema specifications. The results of the validation may be a human readable document and/or a machine readable reprentation regarding the quality issues found in the data. This paper reports about work in progress, but the first prototype of the platform is already operational on the web as a service http://ldf.fi.

Juridical information is important to organizations and individuals alike and is linked to from all walks of life. The Finnish government has published the Finlex Data Bank for searching and browsing legislation documents. However, the data there is not yet open, is based on a traditional XML schema, and does not conform to new semantic metadata standards. There are many difficulties in maintaining and using the site in, e.g., data harvesting, interoperability, querying, and linking that could be mitigated by the Semantic Web technologies. This paper presents an approach and a project—including first results—for publishing and using Finnish legislation as a 5-star Linked Open Data service.

We present an ontology for managing the scientific and common names of birds. The ontology is based on the TaxMeOn meta-ontology model for biological names. The ontology is in use as an ontology service and it has been applied in a bird watching system.

University data is typically stored in separate data silos even though the data is implicitly richly related together. Such data has a large and diverse user base, including faculty members, students, industrial partners, alumnis, collaborating universities, and media. In this paper, we demonstrate two tools for understanding and using the contents of linked university data. The first tool, Visualization Playground (VISU), supports querying and visualizing the data for example for illustrating emerging trends in universities (e.g., about publications) and for com- paring differences. The second tool, Vocabulary Visualizer (V^2), demon- strates the usage of vocabularies in the Linked University Data Cloud. It reveals what kinds of data different universities have published, and what terms are used to describe the contents. Such analysis is a basis for facilitating design of Linked Data applications across university data boundaries.

Animals and plants are referred to using scientific or common names depending on the expertise of an audience or a source of data. The names change in time and therefore their usage as identifiers as such is problematic. We present a solution for managing and using plant names as an ontology. The ontology is based on the TaxMeOn meta-ontology for biological names. In order to refer to organisms unambiguously and publish information as Linked Data on the web, the names are given URIs. The ontology is developed collaboratively and it supports the approval process and temporal tracking of the common names. We introduce an ontology service of plant names for end-users and provide user interfaces and APIs for integrating the ontology into applications.

Observational data about species of public interest, such as birds and butterflies, is often created and collected by volunteered citizen scientists, and used by professionals for managing biodiversity. The education and skills of the citizens participating in the work varies a lot, and the process of making observations is typically not systematic but rather ad hoc. As a result, the quality of the observational data in repositories, such as the Global Biodiversity Information Facility GBIF Data Portal, is often not good, hampering its utilization severely. This paper presents an approach for enhancing data quality in a citizen science setting, and presents a mobile tool BirdWatch for citizen observers, mitigating difficulties in producing high quality Linked Data for biodiversity management.

Semantic and context knowledge have been envisioned as an appropriate solution for addressing the content heterogeneity and information overload in mobile Web information access, but few have explored their full potential inmobile scenarios, where information objects refer to their physical counterparts, and retrieval is context-aware and personalized for users. We present SMARTMUSEUM, a mobile ubiquitous recommender system for the Web of Data, and its application to information needs of tourists in context-aware, on-site access to cultural heritage. The SMARTMUSEUM system utilizes Semantic Web languages as the form of data representation. Ontologies are used to bridge the semantic gap between heterogeneous content descriptions, sensor inputs, and user profiles. The system makes use of an information retrieval framework where in context data and search result clustering are used in recommendation of suitable content for mobileusers. Results from laboratory experiments demonstrate that ontology-based reasoning, query expansion, search result clustering, and context knowledge lead to significant improvement in recommendation performance. The results from field trials show that the usability of the system meets users’ expectations in real-world use. The results indicate that semantic content representation and retrieval can significantly improve the performance of mobile recommender systems in knowledge-rich domains.

Ontology repositories, such as NCBO Bioportal, ONKI and Cupboard, help finding and using ontologies on the Semantic Web. However, currently each ontology repository constitutes a separate island with its own user interface, APIs, users, ontology languages and set of ontologies. Because there is not a universal way to access all ontology repositories, doing global search, browsing, and inference over all available ontology repositories turns out to be technically difficult and is generally not done. Ontologies are not reused as much as they could and hence the full potential of ontologies is not achieved. To address the problem, we propose the Normalized Ontology Repository (NOR) approach to make the ontology repositories universally accessible while maintaining their unique functionalities and strengths. The SKOS language is used as the lowest common denominator for presenting the ontologies. In addition, a simple API for searching and accessing the ontologies is defined. As a proof-of-concept evaluation, we present three case implementations to demonstrate the NOR approach: 1) the distributed architecture of the ONKI repository, 2) the metasearch for ONKI and NCBO Bioportal, and 3) publishing informal ontological concept collections as NOR end-points, demonstrated with the semantic portal CultureSampo and the metadata editor SAHA.

Academic users often find work with online primary sources both rewarding and challenging. Improving subject access in these sources is essential as digital collections propagate and work with primary sources becomes increasingly important in humanities curricula. A user needs assessment was conducted with humanities users at the University of Colorado Boulder to facilitate engagement with these sources. Two of the major user needs identified were improving findability and context, particularly for historical subjects. Linked Data can help meet these needs by linking related concepts in the sources using a specialized vocabulary, enriching them with outside resources, and enabling semantically rich services that empower users. This paper discusses a project the authors undertook to enhance subject access in CU’s WWI Collection Online by deep linking historical data on the civilian experience in occupied Belgium. This work is intended to lead to a richer understanding of forces shaping the WWI period.

BookSampo is a joint project between the Finnish public libraries and semantic web researchers, to improve fiction literature search and recommendation. In the project, dozens of librarians around Finland have used a collaborative web-based metadata editor to input diverse knowledge about fiction literature into a shared database. Particularly, the project has sought to improve access by indexing not only bibliographical information about the books, but focusing on the content and context of the works. In order to do this, the database employs advanced techniques such as functional, content-centered indexing, ontological vocabularies and the networked data model of linked open data. To demonstrate the functionality this makes possible, the fiction literature portal http://www.kirjasampo.fi/ was created. This portal uses the knowledge created in the project to offer advanced semantic search and recommendation based on the database created. In addition, web services exposing direct access to the data have been used for example in culture hack events to answer more complex questions, such as where in Finland are the most crimes committed in fiction literature.

Events are an essential component of cultural heritage (CH) Linked Data (LD): they link actors, places, times, objects, and other events into larger narrative structures, providing a rich basis for semantic searching, recommending, analysis, and visualization of CH data. This paper argues that shared vocabularies (gazetteers, ontologies) of events, such as the “Battle of Normandy” or “Crucifixion of Jesus”, are necessary to facilitate the aggregation and linking of heterogeneous content from various collections. For example, biographies, histories, photos, and paintings often reference or depict events. A set of general requirements for an event gazetteer is presented, based on the needs of publishing, aggregating, and reusing cultural heritage content as Linked Data. After this, a metadata model addressing the presented requirements for representing historical events is outlined. The model is being applied in a case study aimed at developing an event ontology for World War I (WWI). Our goals from an end-user perspective are twofold: 1) Facilitate event-based cataloging for curators in memory organizations; 2) Utilize semantic event descriptions and narrative event structures in end-user applications for searching and linking documents and other content about WWI, and for structuring and visualizing them.

Museums and archives collect and store documentation of processes of intangible cultural heritage (ICH), such as craftsmanship skills, acts, and events recorded in videos, audio tapes, manuscripts, photos, and transcriptions. Such recordings are typically catalogued in an object-centric way as documents, using schemas such as Dublin Core. Also in event-centric models the focus has been on tangible cultural heritage. In this article we point out the importance of cataloguing not only the documentation object or related events, but the actual cultural process, such as a craftsmanship skill. Using special process-centric metadata for ICH, one can search for information about the elements and parts of intangible processes, not only documentation objects. Furthermore, process descriptions can be linked to related tangible and intangible objects in collections and Linked Data repositories on the web, facilitating rich and detailed semantic recommendations to end-users. To test and evaluate this idea, we created a metadata model for representing cultural processes, and applied it to the video documentation of traditional shoemaking with visualization and real time semantic recommendations on the CultureSampo portal.

TravelSampo [1] is a prototype system, by which museums are able to create interactively audio guide tours inside museums and outside in the open air. The system includes a web-based editor by which a curator can describe objects in an exhibition, or in the open air, using a set of shared ontologies published in the National Ontology Service ONKI (http://onki.fi/), and upload related audio descriptions, text, and images. Each exhibit object is given an identifier and a geo-location. When the end-user is near the object, either in a museum or in the open air, information related to the object can be given to her based on the object identifier or GPS location. A major novelty of TravelSampo lies in its ability to associate the object metadata automatically with millions of semantically related pieces of information available though the Linked Data cloud (http://linkedata.org/) and the CultureSampo system (http://www.kulttuurisampo.fi/). For example, a painting can be linked, based on the underlying ontologies and metadata, with the biography of the painter in Wikipedia or in the National Biography, with other paintings of the artist in the collections of other museums, with photos and books about the artist, and so on. This gives the end-user a richer experience than is possible with traditional audio guide systems. For the museums, TravelSampo offers a cost-efficient and dynamic way of creating information rich audio guide programs, and re-using and linking each others collections through linked data, leading to a win-win situation. The paper presents and discusses the underlying ideas of TravelSampo and our experiences in developing the systems especially from the content publishers’, i.e. the museums’ viewpoint. [1] E. Mäkelä, J. Väätäinen, R. Alitalo, O. Suominen, E. Hyvönen: Discovering Places of Interest through Direct and Indirect Associations in Heterogeneous Sources - The TravelSampo System. Terra Cognita 2011: Foundations, Technologies and Applications of the Geospatial Web, CEUR Workshop Proceedings, Vol-798, 2011. http://ceur-ws.org/Vol-798/proceedings.pdf

Ontologiat ovat keskeinen osa semanttista webiä: ne toimivat yhteisinä jaettuina käsitteistöinä, joiden avulla tietokoneet voivat käsitellä tietoa älykkäämmin. Jotta eri toimijat voivat hyödyntää yhteisiä käsitteistöjä sovelluksissaan, ontologiat on julkaistava heidän käyttöönsä. Yksinkertaisimmillaan ontologiat voidaan julkaista tiedostomuodossa. Tällöin jokainen toimija joutuu toteuttamaan itse toiminnallisuuksia ontologioiden hyödyntämiseen. Koska osa toiminnallisuuksista on yleisiä, useissa järjestelmissä toistuvia, niiden toteuttaminen valmiina palveluina on mielekästä. Palveluita voidaan tarjota ihmiskäyttäjille käyttöliittymäkomponentteina sekä ohjelmalliseen käyttöön rajapintoina, joita käyttämällä toiminnallisuudet voidaan integroida asiakasjärjestelmiin. Tässä artikkelissa kuvataan ontologioiden käyttäjäryhmien tarpeita sekä ontologiapalveluiden toteutuksia. Yleisten ontologioiden käyttämiseen liittyvien toiminnallisuuksien tarjoamiseksi esitetään ontologiapalvelu ONKI, joka on osa Suomalaiset semanttisen webin ontologiat -hankesarjassa (FinnONTO, 2003–2012) kehitettyä ontologiainfrastruktuuria. Artikkeli perustuu Jouni Tuomisen pro gradu -työhön, jolle Tietojenkäsittelytieteen Seura ry myönsi lukuvuoden 2009–2010 pro gradu -palkinnon. Tutkimustyöhön ovat osallistuneet myös Kim Viljanen ja Eero Hyvönen.

This paper presents the CultureSampo system for publishing heterogeneous linked data as a service. Discussed are the problems of converting legacy data into linked data, as well as the challenge of making the massively heterogeneous yet interlinked cultural heritage content interoperable on a semantic level. Novel user interface concepts for then utilizing the content are also presented. In the approach described, the data is published not only for human use, but also as intelligent services for other computer systems that can then provide interfaces of their own for the linked data. As a concrete use case of using CultureSampo as a service, the BookSampo system for publishing Finnish fiction literature on the semantic web is presented.

Linked data related to places has a potential to offer a vastly superior collection of information to base search and recommendation functionality on in eTourism visit planning as well as location-aware mobile applications. Particularly, through linked data, besided places interesting in themselves, it is possible to discover places interesting only through association, such as being the venue for a concert by an artist with an interesting genre. However, in order to harness this collective data source, challenges relating to data heterogeneity, quality, scale, and indexing and querying complexity must be resolved. In this paper, the TravelSampo visit planning and mobile application is presented, which tackles these issues. Using the system, queries describing both simple and complex interests can be run over some 17 million places of interest from over 20 vastly heterogeneous sources.

Manufacturing companies face the challenge of maintaining documentation and knowledge about their projects and products, scattered in heterogenous, distributed databases, represented in different formats and languages, and hosted in mutually incompatible systems. At the same time, the knowledge needs to be accessed on a global level from different perspectives and user groups, such as project planners, designers, and maintenance personnel. This paper presents a case study, based on real datasets of a major international diesel engine and power plant manufacturer, where these problems are addressed simultaneuosly by harmonizing the datasets from different sources using RDF, and by linking them together into a global repository using shared resources. Based on the global RDF store, services for both human and machine users, such as a faceted search engine and a SPARQL end-point, can be provided to support access from different perspectives to the company knowledge base.

BookSampo is a semantic portal in use, covering metadata about practically all Finnish fiction literature of Finnish public libraries on a work level. The system introduces a variety of semantic web novelties deployed into practise: The underlying data model is based on the emerging functional, content-centered metadata indexing paradigm using RDF. Linked Data (LD) principles are used for mapping the metadata with tens of interlinked ontologies in the national FinnONTO ontology infrastructure. The contents are also linked with the large LD metadata repository of related cultural heritage content of CultureSampo. BookSampo is actually based on using CultureSampo as a semantic web service, demonstrating the idea of re-using semantic content from multiple perspectives without the need for modifications. Most of the content has been transformed automatically from existing databases, with the help of ontologies derived from thesauri in use in Finland, but in addtion tens of volunteered librarians have participated in a Web 2.0 fashion in annotating and correcting the metadata, especially regarding older litarature. For this purpose, semantic web editing tools and public ONKI ontology services were created and used. The paper focuses on lessons learned in the process of creating the semantic web basis of BookSampo.

We present a comprehensive system for producing interoperable metadata for Linked Open datasets and governmental datasets published in various formats.

Linked Open Aalto is a research project aiming at developing a semantic web approach for creating and publishing interlinked educational, research, and managerial contents produced at different communities, schools, departments, research groups, and persons in Aalto. By using semantic Linked (Open) Data principles, technologies, and open datasets available, Aalto contents can be interlinked with related teaching and research materials in Finland and internationally. By aggregating and combining local contents from separate incompatible data silos and systems, the end-user can be provided with a global, cross-disciplinary perspective to knowledge produced in Aalto and other universities. For example, a web page describing a course can be interlinked automatically with related research results, publications, projects, Wikipedia pages, research groups, researchers, internationally available video lectures, open course materials, events in Aalto, conferences, blog discussions, and so on.

Semantic web technologies have introduced the idea of annotating content in terms of concepts taken from ontologies. Since concepts are defined in terms of properties and relations to other concepts, descriptions grow up into larger RDF graphs that can be used as a basis for data integration and intelligent information retrieval. Since ontologies do not typically contain all the possible concepts needed for annotation, it is usually necessary to offer the annotator the possibility to introduce new free keywords or tags in addition to the predefined ontology concepts. The problem then is that free keywords/tags do not have ontological connections to the rest of the RDF graph, unless such relations are defined by the annotator.We present a process for integrating free keywords into the ontological framework, and a practical tool implementation of it, discussing the challenges and possibilities introduced by the system. We also describe a case study performed for the Finnish Defence Forces, where the tool is used for creating a faceted semantic search portal featuring the free keywords and the ontological concepts at the same time.

We consider ontology evolution in a system of light-weight Linked Data ontologies, aligned with each other to form a larger ontology system. When one ontology changes, the human editor must keep track of the actual changes and of the modifications needed in the related ontologies in order to keep the system consistent. This paper presents an analysis tool MUTU, by which such changes and their potential effects on other ontologies can be found. Such an analysis is useful for the ontology editors for understanding the differences between ontology versions, and for updating linked ontologies when changes occurred in other components of an ontology system.

The number of open datasets available on the web is increasing rapidly with the rise of the Linked Open Data (LOD) cloud and various governmental efforts for releasing public data in different formats, not only in RDF. The aim in releasing open datasets is for developers to use them in innovative applications, but the datasets need to be found first and metadata available is often minimal, heterogeneous, and distributed making the search for the right dataset often problematic. To address the problem, we present DataFinland, a semantic portal featuring a distributed content creation model and tools for annotating and publishing metadata about LOD and non-RDF datasets on the web. The metadata schema for DataFinland is based on a modified version of the voiD vocabulary for describing linked RDF datasets, and annotations are done using an online metadata editor SAHA connected to ONKI ontology services providing a controlled set of annotation concepts. The content is published instantly on an integrated faceted search and browsing engine HAKO for human users, and as a SPARQL endpoint and a source file for machines. As a proof of concept, the system has been applied to LOD and Finnish governmental datasets.

Ontologies and vocabularies are a key resource for creating interoperable metadata on the Semantic Web. To make finding and using ontologies easier, the idea of Ontology Repositories has been introduced with current implementations including e.g. the NCBO Bioportal, ONKI and Cupboard. There is a genuine need for different kinds of Ontology Repositories, each focusing on different kinds specific user-needs, different ontologies and different organizational requirements which cannot be addressed by a single general implementation. However, at the moment each Ontology Repository is a separate island with its own user interfaces and APIs. They also use varying ontology languages such as OWL, SKOS, and RDF Schema. Due to this, global search, browsing, and inference over the repositories is difficult and generally not done which means that, for example, finding and reusing existing ontologies becomes difficult. To address the problems, we have developed a loosely coupled Network of Ontology Repositories (NOR) architecture that makes the repositories globally interoperable while maintaining their unique functionalities and strengths. To participate in the network, each ontology repository is required to implement a shared API. As a proof-of-concept evaluation, we present three case implementations demonstrating different aspects of the NOR approach: 1) internal distributed architecture of ONKI, 2) global search of ONKI and NCBO Bioportal, 3) publishing non-ontological concept collections as NOR endpoints, demonstrated with the semantic portal CultureSampo and the metadata editor SAHA.

Biodiversity management requires the usage of heterogeneous biological information from multiple sources. Indexing, aggregating, and finding such information is based on names and taxonomic knowledge of organisms. However, taxonomies change in time due to new scientific findings, opinions of authorities, and changes in our conception about life forms. Furthermore, organism names and their meaning change in time, different authorities use different scientific names for the same taxon in different times, and various vernacular names are in use in different languages. This makes data integration and information retrieval difficult without detailed biological information. This paper introduces a meta-ontology for managing the names and taxonomies of organisms, and presents three applications for it: 1) publishing biological species lists as ontology services (ca. 20 taxonomies including more than 80,000 names), 2) collaborative management of the vernacular names of vascular plants (ca. 26,000 taxa), and 3) management of individual scientific name changes based on research results, covering a group of beetles. The applications are based on the databases of the Finnish Museum of Natural History and are used in a living lab environment on the web.

Structured semantic metadata about unstructured web documents can be created using automatic subject indexing methods, avoiding laborious manual indexing. A succesful automatic subject indexing tool for the web should work with texts in multiple languages and be independent of the domain of discourse of the documents and controlled vocabularies. However, analyzing text written in a highly inflected language requires word form normalization that goes beyond rule-based stemming algorithms. We have tested the state-of-the art automatic indexing tool Maui on Finnish texts using three stemming and lemmatization algorithms and tested it with documents and vocabularies of different domains. Both of the lemmatization algorithms we tested performed significantly better than a rule-based stemmer, and the subject indexing quality was found to be comparable to that of human indexers.

People frequently need to find knowledge related to places when they plan a leisure trip, when they are executing that plan in a certain place, or when they want to virtually explore a place they have visited in the past. In this chapter we present and discuss a set of methods for searching and browsing spatiotemporally referenced knowledge related to cultural objects, e.g. artifacts, photographs and visiting sites. These methods have been implemented in the semantic cultural heritage portal CULTURESAMPO that offers map-based interfaces for a user to explore hundreds of thousands of content objects and points of interest in Finland. Our goal is to develop and demonstrate novel ways to help the user 1) to decide where to go for a trip, and 2) to learn more about the neighborhoods and points of interest during the visit.

Ontologies and vocabularies are a key resource for creating interoperable metadata on the Semantic Web. To make the finding and using ontologies easier, the idea of Ontology Repositories have been introduced with current implementations including e.g. the NCBO Bioportal, ONKI and Cupboard. However, at the moment each ontology repository is a separate island with its own user interfaces and APIs. They also use varying ontology languages such as OWL, SKOS, RDF Schema and others. Due to this, global search, browsing, and inference over the repositories is difficult and generally not done. At the same time, there is a genuine need for different kinds of Ontology Repositories, each focusing on different kinds specific user-needs, different ontologies and different organizational requirements which can not be addressed by a single global implementation. Since there are benefits of having interoperability among the repositories, we have developed a loosely coupled Network of Ontology Repository (NOR) architecture that makes the repositories globally interoperable while maintaining their unique functionalities and strengths. To participate in the network, each ontology repository is required to implement a shared API. As a proof-of-concept, we present a global metasearch prototype for searching simultaneously hundreds of ontologies in the ONKI and NCBO Bioportal repositories.

Ontology repository systems are used for publishing and sharing ontologies and vocabularies for content indexing, information retrieval, content integration, and other purposes. However, interlinking these distributed repositories to provide global search and browsing over the repositories has not been made. In the spirit of Linked Open Data, we propose creating a network of Linked Open Ontology Services (LOOS) consisting of ontology repositories that publish their content using a shared API. To test the approach, we have defined an HTTP API and present a proof-of-concept implementation consisting of three client applications that are used for accessing a LOOS network of over 50 ontology servers, part of the Ontology Library Service ONKI.

Finding ontologies and concepts from a collection of ontologies is a recurring task in many use cases, such as content indexing, searching, and ontology developing. To facilitate this, efficient search and browsing methods are needed. This paper introduces ONKI2, an ontology browser providing a user interface for a repository of ontologies. The system provides a multi-facet search facility for finding an ontology. Finding concepts is supported by autocompletion-based text search that can be refined with additional restrictions. ONKI2 is in use in the Finnish Ontology Library Service ONKI for a collection of 79 ontologies and vocabularies.

Ontology repository systems are used for publishing and sharing ontologies. However, currently the repositories form separate islands of ontologies, which hinders the user from finding and utilizing the most suitable ontological concepts and ontologies on a global level. In contrast, this paper presents the idea of creating a network of Linked Open Ontology Services (LOOS) based on a set of ontology services that publish their content via a shared API. This facilitates global search and browsing over all ontologies in the network. LOOS has been implemented in the National Finnish Ontology Service ONKI serving currently 79 ontologies.

Publishing information about upcoming events such as concerts and discussion group meetings in a structured format allows the event information to be aggregated, filtered and delivered to potential participants. Making automatic personalized recommendations about events requires structured metadata such as machine-understandable locations and semantic descriptions about the topic and audience of the event. We present a survey of the state of current semantic representation formats for events, including iCalendar and its RDFa and microformat representations, and show that their support for expressing rich structured metadata is limited. We have also tested how well different tools support and understand the formats. Based on the surveys we have implemented a rich event information schema for a health-oriented activity portal and developed an aggregation and validation tool for gathering and processing event information.

European museums and other cultural institutions host rich collections that have ability to attract EU citizens and tourists. Cultural objects, e.g. paintings, in these collections are related in many ways and in many cases they refer to same underlying concepts, people and places. The Cultural Heritage Knowledge Exchange Platform, SMARTMUSEUM requires that these collections are interoperable over cultural and language barriers, and provides a mobile publication channel for collections.

Providing citizens with reliable, up-to-date and individually relevant health information on the web is done by governmental, non-governmental, business and other organizations. Currently the information is published with little co-ordination and co-operation between the publishers. For publishers, this means duplicated work and costs due to publishing same information twice on many websites. Also maintaining links between websites requires work. From the citizens point of view, finding content is difficult due to e.g. differences in layman’s vocabularies compared to medical terminology and difficulties in aggregating information from several sites. To solve these problems, we propose as a solution a national scale semantic publishing system HealthFinland which consists of a 1) a centralized content infrastructure of health ontologies and services with tools, 2) a distributed semantic content creation channel based on several health organizations, and 3) an intelligent semantic portal aggregating and presenting the contents from intuitive and health promoting end-user perspectives for human users as well as for other web sites and portals.

Historical texts are an important component of cultural heritage, and are being digitized and published on the web in various portals for the researhers and the public. However, searching and linking them with related contents is challenging due the non-structured text form, digitization errors, and the differences and variations between old and modern language, including historical names (e.g. places), used for querying. This paper addresses these issues by presenting an approach and a system for publishing old texts on the semantic web. As a case study, an existing historical newspaper archive on the web is considered. In our model, semantic metadata is added to the text using automated concept extraction methods. Search is implemented with semantic techniques, by creating a multi-faceted search interface for the text materials. Problems due to OCR errors and spelling variants are addressed with a fuzzy string matching algorithm trying to guess corresponding words in a lexicon, and giving suggestions for corrected words forms. References between texts in the library as well as links between the library and external knowledge sources are formed by using shared ontologies for semantic annotations.

Authors and documents with identical titles are common in the digital library environment. In order to manage identities correctly, authority control is used by library and information scientists for disam- biguating and cross-referencing entity names. We argue that the benefits of traditional authority control can be enhanced by using techniques and technologies of the Semantic Web, leading to simpler management of multiple languages, better linkability of resources, simpler reuse of au- thority registries in applications, and less work in indexing. To demon- strate our propositions, we have created a prototype of an ontology server and service called ONKI People that is used in two ways: First, it is a centralized authority service providing human end-users with efficient and easy to use authority finding and disambiguation services based on faceted semantic search and visualizations. The services are available on- line also as AJAX and Web Services API for machines to use. Second, the underlying RDF triple store can be used as a content resource in ap- plications such as semantic cultural heritage portals. The paper discusses and demonstrates both use cases in a real life setting.

This paper presents a semantic recommender method and a system for a personalized access to digital cultural heritage through context-aware user pro- filing. Given annotation knowledge-bases, explicit background knowledge in the form of ontologies, a user model capturing the user’s behavior and context, the system produces recommendations. Ontology-based user profiling can be used to reduce cold-start, sparsity and over-specialization problems. In addition, we present a recommendation retrieval method that is based on the vector space model and uses indices that enable fast and scalable implementation of the system.

The Semantic Web extends traditional web documents, i.e. the Web of Pages, with conceptual structures based on ontologies and metadata, i.e. the Web of Data. This paper presents a hybrid document search approach combining the benefits of the traditional text search of literal documents and the semantic search based on their underlying conceptual structures. The approach is based on document expansion, where documents are automatically annotated with not only the concepts explicitly present in a given document, but also with the ontologically related concepts using smaller weights. Our test results using the CLEF Test Suite suggest that document expansion alone achieves better recall than text search at the expense of precision. As a solution, a method of combining document expansion with text search is presented in which better recall was obtained without sacrificing precision. This approach seems promising when integrating unstructured, textual content with the Semantic Web of Data.

In this paper we present an ontology-based query expansion widget which utilizes the ontologies published in the ONKI Ontology Service. The widget can be integrated into a web page, e.g. a search system of a museum catalogue, enhancing the page by providing a query expansion functionality. We have tested the system with general, domain-specific and spatio-temporal ontologies.

CULTURESAMPO is an application demonstration of a national level publication system of cultural heritage contents on the Web, based on ideas and technologies of the Semantic (Web and) Web 2.0. On the semantic side, the system presents new solutions to interoperability problems of dealing with multiple ontologies of different domains, and to problems of integrating multiple metadata schemas and cross-domain content into a homogeneous semantic portal. A novelty of the system is to use semantic models based on events and narrative process descriptions for modeling and visualizing cultural phenomena, and for semantic recommendations. On the Web 2.0 side, CULTURESAMPO proposes and demonstrates a content creation process for collaborative, distributed ontology and content development including different memory organizations and citizens. The system provides the cultural heritage contents to end-users in a new way through multiple (nine) thematic perspectives, based on semantic visualizations. Furthermore, CULTURESAMPO services are available for external web-applications to use through semantic AJAX widgets.

Semantic web techniques can be used to relate two things together. However, usually this relation is not accompanied with a measure that would tell how interesting the relation is. Data mining tradition provides interestingness measures; it is natural to try and fit semantic web and data mining traditions together. In this paper we use support and confidence values provided by association rule mining as interestingness measures for relations. The presented method is tailored to location ontologies in order to find out what interesting mutual relations two places have based on annotations in the cultural heritage domain. The method also uses ontology-based reasoning to group places together. We present tests of running the method against a set of over 60,000 annotations in order to find out cultural heritage connections between places.

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.

This paper discusses problems of creating and using ontology library services in production use. One approach to a solution is presented with an online implementation--the Finnish Ontology Library Service ONKI--that is in pilot use on a national level in Finland. ONKI contributes to previous research on ontology libraries in many ways: First, mashup and web service support with various tools is provided for cost-efficient utilization of ontologies in indexing and search applications. Second, services covering the different phases of the ontology life cycle are provided. Third, the services are provided and used in real world applications on a national scale. Fourth, the ontology framework is being developed by a collaborative effort by organizations representing different application domains, such as health, culture, and business.

We present an overview of CultureSampo, an ambitious system for creating a collective semantic memory of the cultural heritage of a nation on the Semantic Web 2.0, combining ideas underlying the Semantic Web and the Web 2.0. The system addresses the semantic web challenge of aggregating highly heterogeneous, cross-domain cultural heritage collections and other contents into a semantically rich intelligent system for human and machine users. At the same time, CultureSampo is an approach to solve the social and practical Web 2.0 challenge of organizing the underlying collaborative ontology development and content creation work of memory organizations and citizens. This paper focuses on CultureSampo’s search, recommendation, and visualization services for the end-users. The key idea here is to access cultural heritage on the Semantic Web through nine “thematic perspectives”, such as places on the maps, the social network of cultural persons, timelines, and narrative texts, e.g. biographies and literary works.

This paper presents an overview of the SemanticWeb 2.0 application CultureSampo, an ambitious system for creating a collective semantic memory of the cultural heritage of a nation on the Semantic Web 2.0, combining ideas underlying the Semantic Web and the Web 2.0. The system addresses the semantic web challenge of aggregating highly heterogeneous, cross-domain cultural heritage content into a semantically rich intelligent system for human and machine users. At the same time, CultureSampo is an approach to solve the social and practical Web 2.0 challenge of organizing the underlying collaborative ontology development and content creation work of memory organizations and citizens.

Ontologies aim to capture knowledge about things and their relationships. Publishing ontologies on the Semantic Web enables people and organizations to use shared ontologies in annotating e.g. photographs, videos, music, and other types of cultural objects. Search engines also use relationships provided by ontologies in semantic search, e.g. for query expansion or for view-based search. However, building ontologies is a time-consuming process, and it should be helped by automatic finding of interesting, possible relationships. Finding the correct concept for annotation purposes is helped by subsumption and partonomy hierarchies and associative relationships. In this paper we show how an analysis of co-occurrences of concepts in annotations can be used to provide interesting relationships for enriching ontological structures. We use association rule mining techniques and test the idea using a set of annotations of cultural objects in CULTURESAMPO portal and the Finnish General Upper Ontology YSO. The results are visualized in the ONKI SKOS browser to give an additional layer on top of the original relationships of the YSO ontology. An analysis shows that best ranked relationships should also be included in the ontology as subclassof or associative relationships.

This paper presents solutions and lessons learned in FinnONTO project carried out in Finland in 2003–2007. The paper focuses on three aspects of interoperability of digital collections. First, transforming thesauri to ontologies. Second, publishing ontologies for the use of indexers and content providers. Third, ontology based methods for improving end user access to digital collections.  The first aspect is analysed through case studies done with Finnish thesauri. The second is discussed by presenting the ONKI ontology server. The last aspect is demonstrated in the scope of the semantic portal CultureSampo for publishing cultural heritrage on the Semantic Web.

Kulttuurisampo kokoaa suomalaisen kulttuurin palapeliä aivan uudella tavalla, kirjoittavat Eero Hyvönen ja Suvi Kettula

Artikkelissa luodaan katsaus kansallisessa Suomalaiset semanttisen webin ontologiat hankkeessa FinnONTO 2003-2007 ja FinnONTO 2.0 2008-2010 kehitettyihin paikkaontologioihin SUO (Suomalainen paikkaontologia) ja SAPO (Suomen ajallinen paikkaontologia), näiden julkaisemiseen AJAX-palveluina Kansallisessa ontologiapalvelussa ONKI, sekä paikkaontologioiden avulla Kulttuurisampo-portaaliin kehitettyihin palveluhin.

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.

This paper presents the Semantic Web 2.0 application CULTURESAMPO, an ambitious system of creating a collective semantic memory of the cultural heritage of a nation on the Semantic Web 2.0, combining ideas underlying the Semantic Web and the Web 2.0. The system addresses the semantic challenge of aggregating highly heterogeneous, cross-domain cultural heritage into a semantically rich intelligent system for human and machine users. At the same time, CULTURESAMPO is an approach to solve the social and practical Web 2.0 challenge of organizing the underlying collaborative ontology development and content creation work of memory organizations and citizens.

Thesauri and other controlled vocabularies act as building blocks of the Semantic Web by providing shared terminology for facilitating information retrieval, data exchange and integration. Representation and publishing methods are needed for utilizing thesauri efficiently, e.g., in content indexing and searching. W3C has provided the Simple Knowledge Organization System (SKOS) data model for expressing concept schemes, such as thesauri. A standard representation format for thesauri eliminates the need for implementing thesaurus specific rules or applications for processing them. However, there do not exist general tools which provide out of the box support for publishing and utilizing SKOS vocabularies in applications, without needing to implement application specific user interfaces for end users. For solving this problem the ONKI-SKOS server is presented.

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.

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 cost-effectively 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 ready-to-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 have been successfully used in several pilot applications.

Geographic place names are semantically often highly ambiguous. For example, there are 491 places in Finland sharing the same name ”Isosaari” (great island) that are instances of several geographical classes, such as Island, Forest, Peninsula, Inhabited area, etc. Referencing unambiguously to a particular ”Isosaari”, either when annotating content or during information retrieval, can be quite problematic and requires usage of advanced search methods and maps for semantic disambiguation. Historical places introduce even more challenges, since historical metadata commonly make spatiotemporal references to historical regions and places using names whose meanings are non-existing or different in different times. This paper presents how these problems have been addressed in a large Finnish place ontology SUO and a historical geo-ontology SAPO. A location ontology server ONKI-Geo has been created for publishing the ontologies and utilizing them as mashup services. To demonstrate the usability of our ontologies, two case applications in the cultural heritage domain are presented.

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 coverage 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 representing the complete change history of municipalities in Finland during 1865–2007, and the resulting ontology time series is used in the semantic cultural heritage portal CULTURESAMPO to support faceted semantic search of contents and to visualizing historical regions on overlaying maps originating from different historical eras.

This article presents the vision and results of creating a national level cross-domain ontology service infrastructure in Finland in the FinnONTO project. 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 top ontology of 20,000 concepts 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 user interface level as 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. The ontology framework presented is operational on the web and is being used in creating the application demonstrations.

In this paper we examine 1) the scope of geo-ontologies used especially for the purposes of information retrieval on the Web, 2) the core geographical concepts and their mutual relations, and 3) the properties the concepts have. Furthermore, we present the Finnish geo-ontology (Suomalainen paikkaontologia, SUO) and discuss the theories and principles that have governed the development process, as well as the limitations and requirements the use of geographical dictionaries as an instance data source have imposed to the content and the structure of SUO.

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.

We argue that an ontology of historical events is needed in semantic portals for cultural heritage due to three reasons. First, ontological identifiers (URIs) of events, such as the World War II or coronation of Napoleon, are needed in order to make collection metadata mutually interoperable in terms of related events---in the vein as identifiers are needed for identifying artifact types, persons, and geolocations when annotating collection items. Second, events are of central importance in creating semantic links between cultural contents in applications such as recommendation systems. Third, historical events are important as content items of their own, forming the backbone of chronological histories.

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.

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.

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.

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 \CS\ was found useful in a preliminary user study.

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.

The Semantic Web is based on using shared ontologies for enabling semantically disambiguated data exchange between distributed systems on the web. This requires, from the ontology publisher s viewpoint, efficient means for publishing ontologies on the web to ensure the availability and acceptance of the ontologies. From the ontology user s viewpoint, support services are needed for utilizing ontologies easily and cost-effectively in the users own systems that are typically legacy systems without ontology support. This paper presents the ONKI ontology server for addressing these vital needs. For the publisher, ONKI provides a server and a Simple Knowledge Organization (SKOS) compatible light-weight ontology browser with ready-made web interfaces for making ontologies available both for human and machine users. For external legacy and other applications, ONKI provides centralized ontology services for semantic disambiguation, concept finding, and concept fetching. A major contribution of ONKI is to provide these services as ready-to-use functionalities for creating mash-up applications very cost-efficiently. Two prototypes of the system---ONKI-SKOS for all kinds of ontologies and ONKI-Geo for geographical ontologies with a map mash-up interface---are operational on the web and are currently being successfully used in several pilot applications.

Geographic place names are widely used but are semantically often highly ambiguous. For example, there are 491 places in Finland sharing the same name Isosaari (great island) that are instances of several geographical classes, such as Island, Forest, Peninsula, Inhabited area, etc. Referencing unambiguously to a particular Isosaari , either when annotating content or during information retrieval, can be quite problematic and requires usage of advanced search methods and maps for semantic disambiguation. This paper presents an ontology server, ONKI-Paikka, for solving the place finding and place name disambiguation problem. In ONKI-Paikka, places can be found by a faceted search engine, combined with semantic autocompletion and a map service for constraining search and for visualizing results. The service can be connected to legacy applications cost-effectively by using Ajax-technology in the same spirit as Google Maps that is used in ONKI-Paikka as a subservice.

This paper concerns the idea of publishing heterogenous cultural content on the Semantic Web. By heterogenous content we mean metadata describing potentially any kind of cultural objects, including artifacts, photos, paintings, videos, folklore, cultural sites, cultural process descriptions, biographies, history etc. The metadata schemas used are different and the metadata may be represented at different levels of semantic granularity. This work is an extension to previous research on semantic cultural portals, such as MuseumFinland, that are usually based on a shared homogeneous schema, such as Dublin Core, and focus on content of similar kinds, such as artifacts. Our experiences suggest that a semantically richer event-based knowledge representation scheme than traditional metadata schemas is needed in order to support reasoning when performing semantic search and browsing. The new key idea is to transform different forms of metadata into event-based knowledge about the entities and events that take place in the world or in fiction. This approach facilitates semantic interoperability and reasoning about the world and stories at the same time, which enables implementation of intelligent services for the end-user. These ideas are addressed by presenting the vision and solution approaches taken in two prototype implementations of a new kind of cross-domain semantic cultural portal “CULTURESAMPO—Finnish Culture on the Semantic Web”.

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 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 \HF\ 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 paper presents a system for searching semantic relations between web resources, in our case significant persons of art history. The system is based on the Union List of Artists Names (ULAN) metadata of some 120,000 persons and organizations.

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.

Creation of rich, ontology-based metadata is one of the major challenges in developing the Semantic Web. Emerging applications utilizing semantic web techniques, such as semantic portals, cannot be realized if there are no proper tools to provide metadata for them. This paper discusses how to make provision of metadata easier and cost-effective by an annotation framework comprising of annotation editor combined with shared ontology services. We have developed an annotation system supporting distributed collaboration in creating annotations, and hiding the complexity of the annotation schema and the domain ontologies from the annotators. Our system adapts flexibly to different metadata schemas, which makes it suitable for different applications. Support for using ontologies is based on ontology services, such as concept searching and browsing, concept URI fetching, semantic autocompletion and linguistic concept extraction. The system is being tested in various practical semantic portal projects.

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.

This paper concerns the idea of publishing heterogenous cultural content on the Semantic Web. By heterogenous content we mean metadata describing potentially any kind of cultural objects, including artifacts, photos, paintings, videos, folklore, cultural sites, cultural process descriptions, biographies, history etc. The metadata schemas used are different and the metadata may be represented at different levels of semantic granularity. This work is an extension to previous research on semantic cultural portals, such as MuseumFinland, that are usually based on a shared homogeneous schema, such as Dublin Core, and focus on content of similar kinds, such as artifacts. Our experiences suggest that a semantically richer event-based knowledge representation scheme than traditional metadata schemas is needed in order to support reasoning when performing semantic search and browsing. The new key idea is to transform different forms of metadata into event-based knowledge about the entities and events that take place in the world or in fiction. This approach facilitates semantic interoperability and reasoning about the world and stories at the same time, which enables implementation of intelligent services for the end-user. These ideas are addressed by presenting the vision and solution approaches taken in two prototype implementations of a new kind of cross-domain semantic cultural portal “CULTURESAMPO—Finnish Culture on the Semantic 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 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 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.

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 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.

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 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.

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.

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.