This paper introduces a prospective study of the potential of spatio-temporal graphs (ST-graphs) and knowledge graphs (K-graphs) for the modelling of geographical phenomena. While the integration of time within GIS has long been a domain of major interest, alternative modelling and data manipulation approaches derived from graph and knowledge-based principles provide many opportunities for many application domains. We first survey graph principles and how they have been applied to GIS and a few representative domains to date. A comprehensive analysis of the principles behind K-graphs, respective data representation and manipulation capabilities is discussed. The perspectives offered by a close integration of ST-graphs and K-graphs are explored. The whole approach is illustrated and discussed in the context of maritime transportation.
Pervasive Environments offer new opportunities for users to dynamically access resources and services based on information characterizing their situation (context), generally assuming that this information is correct and trustworthy. In this scenario, the Quality of Context information (QoC) plays an important role for improving context-based adaptation processes and for ensuring the correct behavior of context-aware applications and services. Some research attempts have been done for modeling and measuring the quality of raw context information sensed from the environment. However, so far no attention has been paid to the quality evaluation of derived and inferred context information. This paper describes an approach for modeling and measuring quality of raw, inferred, and derived context information based on the following points of view: privacy, security, precision, completeness, and resolution. We propose a context management framework that support QoC in their various layers, protecting and providing QoC-enriched context information of users to context-aware applications and services.
23 August 2011 in International Journal of Geographical Information Science
The full integration of time dimensions in GIS still represents a research challenge. A number of systems provide ways to visualise harmonised timestamped geographical data onto maps, with interpolated curves representing how these data have changed over time. However, these systems frequently mask the concerns linked to changes in territorial organisations and the harmonisation of data. In fact, the development of a territory should be considered in connection with its neighbourhood, governance and genealogy relationships. This article focuses on the difficulties linked with the ‘change of support problem’, which can arise when conducting spatio-temporal analysis of data. First, we present a data model handling the changing relationships between territories. Then, we illustrate how this model can be instantiated using examples that have taken place in Europe. We show how the model can address questions such as that of change blindness. Finally, we explain how hierarchical and genealogical relationships can be used inside an interactive cartographic tool for spatio-temporal analysis. It provides various views of the same phenomena at multiple scales, through an approach that takes into account the changes in territorial organisation.
The continuous evolution of computer capacities, as well as the emergence of the X3D standard has recently boosted the 3D domain. Even if efficient tools that support the designer's work exist, little attention is paid to the reuse of 3D models. Associating some semantics with 3D contents is an important issue for reusing such contents or pieces of content. In this paper, we address this issue by using a generic semantic annotation model for 3D, called 3DSEAM [Bilasco et al. 2005b] (3D SEmantics Annotation Model). 3DSEAM aims at indexing 3D contents considering visual, geometric and semantic aspects. A generic 3D Annotation Framework (called 3DAF) is proposed in order to manage the semantic annotations of 3D objects. 3DAF is instantiated using an MPEG-7-based architecture. An extension of MPEG-7 that addresses 3D content is used. [Bilasco et al. 2005a].