Esko Ikkala

Named Entity Linking in a Complex Domain: Case Second World War History

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 interlinked 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.

AATOS – A Configurable Tool for Automatic Annotation

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 the WarSampo (http://seco.cs.aalto.fi/projects/sotasampo/en/) and Semantic Finlex (http://seco.cs.aalto.fi/projects/lawlod/en/) 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.

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.

Modeling and Using an Actor Ontology of Second World War Military Units and Personnel

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.

TourRDF: Representing, Enriching, and Publishing Curated Tours Based on Linked Data

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.