In this system paper we describe metaphactory, a platform for building knowledge graph management applications. The metaphactory platform aims at supporting different categories of knowledge graph users within the organization by realizing relevant services for knowledge graph data management tasks, providing a rich and customizable user interface, and enabling rapid building of use case-specific applications. The paper discusses how the platform architecture design built on open standards enables its reusability in various application domains and use cases as well as facilitates integration of the knowledge graph with other parts of the organizational data and software infrastructure. We highlight the capabilities of the platform by describing its usage in four different knowledge graph application domains and share the lessons learnt from the practical experience of building knowledge graph applications in the enterprise context.

Abstract. Georeferencing and semantic annotations improve the findability of geoinformation because they exploit relationships to existing data and hence facilitate queries. Unlike georeferencing, which grounds location information in reference points on the earth's surface, semantic annotations often lack relations to entities of shared experience. We suggest an approach to semantically reference geoinformation based on underlying observations, relating data to observable entities and actions. After discussing an ontology for an observer's domain of experience, we demonstrate our approach through two use cases. First, we show how to distinguish geosensors based on observed properties and abstracting from technical implementations. Second, we show how to complement annotations of volunteered geographic information with observed affordances.

Semantic similarity measurement has been an active research area in GIScience and the Semantic Web for many years. However, implementations of these measures were largely missing, not publicly available, or tailored to specific application needs. To foster the application of similarity reasoning in information retrieval, ontology engineering, and spatial decision support, we implemented the SIM-DL semantic similarity server as well as a plug-in for the popular Protégé ontology editor. While SIM-DL has been successfully applied to several application areas, the implemented similarity theory was largely structural, could not handle concept and instance similarity within the same framework, and was based on a Protégé version and DIG interface that have been re-engineered over the last years. This paper introduces a new version, called SIM-DLA, engineered from scratch to addresses these shortcomings. It is based on our new similarity theory, can handle inter-instance and interconcept similarity using the same functions and alignments, and is available for the new Protégé version 4.1.

No abstract

Abstract. Most datasets on the Linked Data Web impose a static view on the represented entities and relations between them, neglecting temporal aspects of the reality they represent. In this paper, we address the representation of resources in their spatial, temporal and thematic context. We review the controversial proposals for the representation of time-dependent relations on the Linked Data Web. We argue that representing and using such relations is made hard through the direct encoding of inadequate conceptualizations, rather than through inherent limitations of the representation language RDF. Using the example of researcher life lines extracted from curricula vitae, we show how to model sequences of activities in terms of events. We build upon the event participation pattern from the DOLCE Ultralite+DnS Ontology and show how places and social roles that people play during their careers relate to events. Furthermore, we demonstrate how scientific achievements can be related to events in a career trajectory by means of temporal reasoning.

No abstract

No abstract

No abstract