Combining Faceted Search with Data-analytic Visualizations on Top of a SPARQL Endpoint

This paper discusses practical experiences on creating data-analytic visualizations in a browser, on top of a SPARQL endpoint based on the results of faceted search. Four use cases related to Digital Humanities research in proposography are discussed where the SPARQL Faceter tool was used and extended in different ways. The Faceter tool allows the user to select a group of people with shared properties, e.g., people with the same place of birth, gender, profession, or employer. The filtered data can then be visualized, e.g., as column charts, with business graphics, sankey diagrams, or on a map. The use cases examine the potential of visualization as well as automated knowledge discovery in Digital Humanities research.Peer reviewe

Maintaining a Linked Data Cloud and Data Service for Second World War History

One of the great promises of Linked Data is to provide a shared data infrastructure into which new data can be imported and aligned with, forming a sustainable, ever growing Linked Data Cloud (LDC). This paper studies and evaluates this idea in the context of the WarSampo LDC that provides a data infrastructure for Second World War related ontologies and data in Finland, including several mutually linked graphs, totaling ca 12 million triples. Two data integration case studies are presented, where the original WarSampo LDC and the related semantic portal were first extended by a dataset of hundreds of war cemeteries and thousands of photographs of them, and then by another dataset of over 4450 Finnish prisoners of war. As a conclusion, lessons learned are explicated, based on hands-on experience in maintaining the WarSampo LDC in a production environment.Peer reviewe

WarVictimSampo 1914–1922: a National War Memorial on the Semantic Web for Digital Humanities Research and Applications

AcceptedThis article presents the semantic portal and Linked Open Data service WARVICTIMSAMPO 1914-1922 about the war victims, battles, and prisoner camps in the Finnish Civil and other wars in 1914-1922. The system is based on a database of the National Archives of Finland and additional related data created, compiled, and linked during the project. The system contains detailed information about some 40,000 deaths extracted from several data sources and data about over 1,000 battles of the Civil War. A key novelty of WARVICTIMSAMPO 1914-1922 is the integration of ready-to-use Digital Humanities visualizations and data analysis tooling with semantic faceted search and data exploration, which allows, e.g., studying data about wider prosopographical groups in addition to individual war victims. The article focuses on demonstrating how the tools of the portal, as well as the underlying SPARQL endpoint openly available on the Web, can be used to explore and analyze war history in flexible and visual ways. WARVICTIMSAMPO 1914-1922 is a new member in the series of "Sampo" model-based semantic portals. The portal is in use and has had 23,000 users, including both war historians and the general public seeking information about their deceased relatives.Peer reviewe

Prosopographical Views to Finnish WW2 Casualties Through Cemeteries and Linked Open Data

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.Peer reviewe

Semantic Systems. In the Era of Knowledge Graphs

This open access book constitutes the refereed proceedings of the 16th International Conference on Semantic Systems, SEMANTiCS 2020, held in Amsterdam, The Netherlands, in September 2020. The conference was held virtually due to the COVID-19 pandemic