The paper “Linked Data and Visualization: Two Sides of the Transparency Coin” by Auriol Degbelo has been accepted for presentation at the upcoming UrbanGIS Workshop on Smart Cities and Urban Analytics.

Abstract: Transparency is an important element of smart cities, and ongoing work is exploring the use of available open data to maximize it. This position paper argues that Linked Data and visualization play similar roles, for different agents, in this context. Linked Data increases transparency for machines, while visualization increases transparency for humans. The work also proposes a quantitative approach to the evaluation of visualization insights which rests on two premises: (i) visualizations could be modelled as a set of statements made by authors at some point in time, and (ii) statements made by experts could be used as ground truth while evaluating how much insights are effectively conveyed by visualizations on the Web. Drawing on the linked data rating scheme of Tim Berners-Lee, the paper proposes a five-stars rating scheme for visualizations on the Web. The ideas suggested are relevant to the development of techniques to automatically assess the transparency level of existing visualizations on the Web.

The paper “Feature-centric ranking algorithms for georeferenced video search” (Authors: Holger Fritze, Auriol Degbelo, Tobias Brüggentisch and Christian Kray) has been accepted for presentation at the upcoming ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems!

Abstract: While it is commonplace to retrieve photos showing a particular feature (e.g. through tools such as Google Pictures or Bing Images), spatial approaches for retrieving videos showing a particular feature (e.g. a building) have yet to be established. This article proposes five ranking algorithms to query georeferenced videos for a specific feature based on the videos’ spatio-temporal metadata. 12 relevance criteria for feature-centric video ranking were compiled from a focus group discussion. From these, four criteria have been selected for implementation: “Feature Depiction”, “Feature Illumination”, “Feature Visibility Duration”, and “Distance to Feature”. These criteria were implemented in five algorithms and evaluated regarding efficiency and user perceived plausibility. The evaluation suggests that the “Feature Visibility Duration” of the video’s viewshed with the queried feature geometry offers a good trade-off between computationally performant and cognitive plausible ranking. The obtained results are relevant to user-centered approaches for interacting with georeferenced videos.

The paper “A Snapshot of Ontology Evaluation Criteria and Strategies” by Auriol Degbelo has been accepted for presentation at the 13th International Conference on Semantic Systems.

Abstract: Ontologies are key to information retrieval, semantic integration of datasets, and semantic similarity analyses. Evaluating ontologies (especially defining what constitutes a “good” or “better” ontology) is therefore of central importance for the Semantic Web community. Various criteria have been introduced in the literature to evaluate ontologies, and this article classifies them according to their relevance to the design or the implementation phase of ontology development. In addition, the article compiles strategies for ontology evaluation based on ontologies published until 2017 in two outlets: the Semantic Web Journal, and the Journal of Web Semantics. Gaps and opportunities for future research on ontology evaluation are exposed towards the end of the paper.