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Analysis of trajectory data is the key to a growing number of applications aiming at global understanding and management of complex phenomena that involve moving objects (e.g. worldwide courier distribution, city traffic management, bird migration monitoring). Current DBMS support for such data is limited to the ability to store and query raw movement (i.e.(More)
Nowadays, many applications need data modeling facilities for the description of complex objects with spatial and/or temporal facilities. Responses to such requirements may be found in Geographic Information Systems (GIS), in some DBMS, or in the research literature. However, most of existing models cover only partly the requirements (they address either(More)
This paper presents a semantic foundation of temporal conceptual models used to design temporal information systems. We consider a modeling language able to express both times-tamping and evolution constraints. We conduct a deeper investigation on evolution constraints, eventually devising a model-theoretic semantics for a full-fledged model with both(More)
With the large-scale adoption of GPS equipped mobile sensing devices, positional data generated by moving objects (e.g., vehicles, people, animals) are being easily collected. Such data are typically modeled as streams of spatio-temporal (x,y,t) points, called <i>trajectories</i>. In recent years trajectory management research has progressed significantly(More)
1. ABSTRACT Although many temporal models have been proposed in the literature, there is still need for a conceptual model capturing the essential semantics of time-varying information that is free of implementation concerns. This paper first discusses important criteria to be considered when assessing the " conceptual " quality of a temporal model. Then,(More)
abstract: The classic evolutionary hypothesis of ecological opportunity proposes that both heterogeneity of resources and freedom from enemies promote phenotypic divergence as a response to increased niche availability. Although phenotypic divergence and spe-ciation have often been inferred to be the primary consequences of the release from competition or(More)
Thanks to the development of the federated systems approach on the one hand and the emphasis on user involvement in database design on the other, the interest in schema integration techniques is significantly increasing. Theories, methods and sometime tools have been proposed. Conflict resolution is the key issue. Different perceptions by schema designers(More)