An adverbial approach for the formal specification of topological constraints involving regions with broad boundaries

Topological integrity constraints control the topological properties of spatial objects and the validity of their topological relationships in spatial databases. These constraints can be specified by using formal languages such as the spatial extension of the Object Constraint Language (OCL). Spatial OCL allows the expression of topological constraints involving crisp spatial objects. However, topological constraints involving spatial objects with vague shapes (e.g., regions with broad boundaries) are not supported by this language. Shape vagueness requires using appropriate topological operators (e.g., strongly Disjoint, fairly Meet) to specify valid relations between these objects; otherwise, the constraints cannot be respected. This paper addresses the problem of the lack of terminology to express topological constraints involving regions with broad boundaries. We propose an extension of Spatial OCL based on a geometric model for objects with vague shapes and an adverbial approach for topological relations between regions with broad boundaries. This extension of Spatial OCL is then tested on an agricultural database

An integrated view of data quality in Earth observation

Data quality is a difficult notion to define precisely, and different communities have different views and understandings of the subject. This causes confusion, a lack of harmonization of data across communities and omission of vital quality information. For some existing data infrastructures, data quality standards cannot address the problem adequately and cannot fulfil all user needs or cover all concepts of data quality. In this study, we discuss some philosophical issues on data quality. We identify actual user needs on data quality, review existing standards and specifications on data quality, and propose an integrated model for data quality in the field of Earth observation (EO). We also propose a practical mechanism for applying the integrated quality information model to a large number of datasets through metadata inheritance. While our data quality management approach is in the domain of EO, we believe that the ideas and methodologies for data quality management can be applied to wider domains and disciplines to facilitate quality-enabled scientific research

Gestion de masses de données temps réel au sein de bases de données capteurs

Les systèmes à base de capteurs sont de plus en plus fréquemment utilisés pour de nombreuses applications comme la gestion de flottes de véhicules, la surveillance de trafic ou encore la surveillance de phénomènes environnementaux ou urbains. Les données acquises pas ces capteurs sont localisées et datées. Elles sont employées dans des applications temps réel et temps différé très diverses gérant de grandes masses de données spatio-temporelles. L’objectif de cet article est de présenter la problématique, et de fournir quelques éléments de réponse aux problèmes scientifiques identifiés. Après la présentation des applications qui nous semblent pertinentes et exploitables, une liste des verrous scientifiques est exposée. Des éléments de réponse sont ensuite détaillés. Ces réflexions et travaux sont issus de membres des équipes de recherche collaborant au sein de l’axe : Réactivité, Mobilité et Temps Réel et du GT : Services Localisés du GDR Sigma.MOTS-CLÉS : Objets mobiles, objets agiles, gestion temps réel, base de données, indexation, métadonnées, suivi de mobilesABSTRACT. Systems based on sensor networks are more and more used from planet wide monitoring systems to tracking systems. Data captured by sensors have attributes concerning date and localisation. Data are used in various applications which are real time or time differed applications managing masses of spatio-temporal data. The objective of this article is to present the problems, and to provide some elements of solution to the identified scientific bolts. After the presentation of the applications which seem to us relevant, a list of the scientific problems is exposed. Brive solutions are then detailed. These reflexions and work result from members of teams of research collaborating within the axis: Reactivity, Mobilité et Temps Réel et du groupe de travail : Services Localisés of the research group sponsored by CNRS, named : GDR Sigma.KEYWORDS: Moving objects Agile objects, real time management, database, ,index, metadata, tracking system