Now showing 1 - 4 of 4
  • Publication
    Adaptive management of multigranular spatio-temporal object attributes
    In applications involving spatio-temporal modelling, granularities of data may have to adapt according to the evolving semantics and significance of data. In this paper we define ST2 ODMGe, a multigranular spatio-temporal model supporting evolutions, which encompass the dynamic adaptation of attribute granularities, and the deletion of attribute values. Evolutions are specified as Event - Condition - Action rules and are executed at run-time. The event, the condition, and the action may refer to a period of time and a geographical area. The evolution may also be constrained by the attribute values. The ability of dynamically evolving the object attributes results in a more flexible management of multigranular spatio-temporal data but it requires revisiting the notion of object consistency with respect to class definitions and access to multigranular object values. Both issues are formally investigated in the paper.
    Scopus© Citations 3  510
  • Publication
    Multi-granular spatio-temporal object models : concepts and research directions
    The capability of representing spatio-temporal objects is fundamental when analysing and monitoring the changes in the spatial configuration of a geographical area over a period of time. An important requirement when managing spatio-temporal objects is the support for multiple granularities. In this paper we discuss how the modelling constructs of object data models can be extended for representing and querying multi-granular spatio-temporal objects. In particular, we describe object-oriented formalizations for granularities, granules, and multi-granular values, exploring the issues of value conversions. Furthermore, we formally define an object-oriented multi-granular query language, and discuss the dynamic adapting of multi-granular data. Finally, we illustrate the current open research issues of multi-granular spatio-temporal data handling.
    Scopus© Citations 12  1040
  • Publication
    Multigranular spatio-temporal models : implementation challenges
    (Association for Computing Machinery (ACM), 2008-11-07) ; ;
    Multiple granularities provide an essential support for extracting significant knowledge from spatio-temporal datasets at different levels of details. They enable to zoom-in and zoom-out spatio-temporal datasets, thus enhancing the data modelling flexibility and improving the analysis of information. In this paper we investigate the implementation issues arising when a data model and a query language are enriched with spatio-temporal multigranularity. We introduce appropriate representations for space and time dimensions, granularities, granules, and multi-granular values. Finally, we discuss how multigranular spatio-temporal conversions affect data usability and how such important property may be guaranteed.
    Scopus© Citations 5  451
  • Publication
    Querying Multigranular Spatio-temporal Objects
    The integrated management of both spatial and temporal components of information is crucial in order to extract significant knowledge from datasets concerning phenomena of interest to a large variety of applications. Moreover, multigranularity, i.e., the capability of representing information at different levels of detail, enhances the data modelling flexibility and improves the analysis of information, enabling to zoom-in and zoom-out spatio-temporal datasets. Relying on an existing multigranular spatio-temporal extension of the ODMG data model, in this paper we describe the design of a multigranular spatio-temporal query language. We extend OQL value comparison and object navigation in order to access spatio-temporal objects with attribute values defined at different levels of detail.
      560Scopus© Citations 7