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 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.

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.

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.

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.

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.

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 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.

Linkitetty data mahdollistaa erillisten aineistojen yhdistämisen, mistä syntyvä kokonaisuus mahdollistaa aineistojen tietojen paremman ymmärtämisen. Aineistojen välisten linkkien avulla voidaan päätellä uutta tietoa helpommin kuin tarkastelemalla aineistoja erikseen. Tutkielmassa käsitellään sotahistoriallisten aineistojen mallintamista ja julkaisua linkitettynä avoimena datana sekä aineistojen automaattista rikastamista muiden aineistojen avulla. Työn tavoitteena oli selvittää miten tällaisia aineistoja kannattaa mallintaa linkitettynä datana, miten niitä kannattaa yhdistää muihin aineistoihin, mitä lisäarvoa tästä saadaan ja miten aineistot kannattaa visualisoida. Aineistoina käytettiin tietokirjoista digitoituja tapahtumia sekä Sotamuseon SA-kuvapalvelun valokuvien metatietoja. Aineistot mallinnettiin käyttäen CIDOC CRM -standardia ja niitä rikastettiin linkittämällä niiden sisältämiä resursseja automaattisesti henkilö-, joukko-osasto- ja paikkaontologioiden avulla. CIDOC CRM:n määrittämä tapahtumakeskeinen mallinnustapa mahdollistaa aineistojen yhteentoimivuuden paitsi toistensa myös muiden historiallisten aineistojen kanssa. Automaattiseen rikastamiseen liittyi monia haasteita, sillä viittaukset toisiin aineistoihin oli poimittava suurelta osin tekstimuotoisista kuvauksista, jolloin ongelmaksi nousee nimettyjen entiteettien kuten henkilöiden ja paikkojen tunnistaminen ja yksilöinti tekstistä. Työssä käsitellään kyseisiä haasteita, esitellään käytetyt ratkaisut ja arvioidaan näiden toimivuutta. Aineistoja visualisoimaan toteutettiin myös JavaScript-sovellukset. Aineistot ja sovellukset on julkaistu osana Sotasampo-portaalia, joka muodostaa yhteenlinkitetyn kokonaisuuden erilaisista aineistoista liittyen toiseen maailmansotaan Suomessa. Portaali palvelee paitsi Suomen historiasta ja sodissa taistelleiden omaistensa liikkeistä kiinnostuneita kansalaisia, myös historian tutkijoita tarjoamalla aineistot vapaasti kyseltävässä rakenteisessa muodossa.

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.

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.

Keywords are used in many document databases to improve search. The process of assigning keywords from controlled vocabularies to a document is called subject indexing. If the controlled vocabulary used for indexing is an ontology, with semantic relations and descriptions of concepts, the process is also called semantic annotation. In this thesis an automatic annotation tool was created to provide the documents with semantic annotations. The application links entities found from the texts to ontologies defined by the user. The application is highly configurable and can be used with different Finnish texts. The application was developed as a part of WarSampo and Semantic Finlex projects and tested using Kansa Taisteli magazine articles and consolidated legislation of Finnish legislation. 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.

Toimijaontologia mallintaa henkilöitä ja henkilöryhmiä linkitetyssä avoimessa datassa. Toimijaontologiamallin tarkoitus on mahdollistaa eri lähteiden aineistojen kokoaminen yhteen ja sen julkaisu yhdenmukaisessa formaatissa, jotta tietoa voidaan hyödyntää niin digitaalisten ihmistieteiden tutkimuksessa kuin tarjoamalla käyttöliittymiä aineiston selaamiseen visuaalisessa muodossa. Laadittu ontologia noudattaa toimija–tapahtuma-mallia. Siinä toimija mallinnetaan häneen liittyvien elämäkerrallisten tapahtumien summana. Ratkaisujen perustana käytettiin CIDOC CRM -standardia, millä haluttiin taata mallin helppo laajennettavuus sekä noudattaa kulttuurihistorialliselle datalle yhdenmukaista julkaisukäytäntöä. Työ on tehty osana laajempaa Sotasampo-projektia, johon kerättiin kattava tietokanta toisen maailmansodan aikaista aineistoa Suomen osalta. Oma osuuteni tässä työssä oli toimijaontologiamallin laatiminen sekä sen populointi sotilashenkilöillä ja -osastoilla. Aineisto on julkaistu avoimena datana (http://www.ldf.fi/dataset/warsa) ja on selattavissa Sotasampo-portaalissa (http://www.sotasampo.fi).

Historiallinen paikkatieto on keskeisessä asemassa muistiorganisaatioiden kokoelmien hallinnassa ja hyödyntämisessä sekä digitaalisten ihmistieteiden tutkimuksessa. Paikkatiedon käsitteleminen muissa kuin erikoistuneissa paikkatietojärjestelmissä sekä paikkatiedon ajallinen ulottuvuus tuovat mukanaan lukuisia haasteita, joihin linkitetyn datan teknologiat ovat tarjonneet lupaavia ratkaisuja. Tässä työssä esitellään kulttuurialan organisaatioiden tarpeeseen kehitetty uusi linkitetyn datan teknologioihin perustuva historiallisten paikkojen ja karttojen palvelumalli, HIPLA. HIPLA-palvelumallin tavoitteena on tarjota yhteinen näkymä eri organisaatioiden hallinnoimaan paikkatietoon ja mahdollistaa hajautettujen paikkatietoaineistojen yhteisöllinen täydentäminen, haku ja selailu sekä nykyisillä että historiallisilla kartoilla. Lisäksi työssä toteutettiin HIPLA-palvelumallin etuja havainnollistava prototyyppisovellus Hipla.fi, jota pilotoitiin osana talvi- ja jatkosodan aineistoja linkitettynä avoimena datana julkaisevaa Sotasampo-projektia. Pilotoinnin tuloksena syntyi talvi- ja jatkosodan paikkaontologia, joka tarjoaa työkalun sotiin liittyvien aineistojen automaattiselle linkitykselle ja aineistojen maantieteelliselle visualisoimiselle.

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.

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.

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 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.