Camossi, Elena

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Camossi, Elena
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Camossi, Elena

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  • Publication
    Spatio-temporal multi-granularity : modelling and implementation challenges
    (University College Dublin. School of Computer Science and Informatics, 2009-08)
    Camossi, Elena 
    ;
    Bertolotto, Michela 
    ;
    Bertino, Elisa 
    Multiple spatial and temporal granularities are essential to extract significant knowledge from datasets at different levels of detail: they enable to zoom-in and zoom-out a dataset, enhancing the data modelling flexibility and being instrumental to boost the analysis of information. Implementing granularities poses several interesting problems. Specifically, in this paper we analyse the issues involved by enhancing a data model and a query language with spatio-temporal multi-granularity, and we figure out efficacious solutions to address all of them. In our exposition, we investigate proper representations for the spatial and the temporal domains; then we conceive an appropriate design for granules and granularities, and for multi-granular values. In particular, mutual relationships among granularities and how they affect granularities design is discussed according to their influence on data access and considering the application of multi-granular conversions. Afterwards, we dedicated to the design of multi-granular spatio-temporal conversions, discussing the multiple ways in which they affect data usability and envisaging how the design of a multi-granular model and query language may guarantee such an fundamental property, reducing uncertainty on the represented values, combining concepts like topologically consistent transformation, probability distributions, invertibility and quasi-invertibility properties. In our discussion, we are influenced on our previous work on multi-granularity. Especially, we expose some of the considerations that guided the design of a multi-granular spatio-temporal model we already proposed as extension of the ODMG data model. In this paper, we describe also some relevant details of a demonstrative object-oriented prototype realized on top of ObjectStore PSE Proj, and of an object-relational prototype realized on top of ORACLE. Both prototypes, even exploiting different characteristics of the underlying data models, prove the effectiveness of the proposed design solutions.
      830
  • Publication
    Attribute refinement in a multigranular temporal object data model
    (Purdue University. Center for Education and Research in Information Assurance and Security, 2009-06)
    Bertino, Elisa 
    ;
    Camossi, Elena 
    ;
    Guerrini, Giovanna 
    Temporal granularities are the unit of measure for temporal data, thus a multigranular temporal object model allows to store temporal data at different levels of detail, according to the needs of the application domain. In this paper we investigate how the integration of multiple temporal granularities in an object-oriented data model impacts on the inheritance hierarchy. In the paper we specifically address issues related to attribute refinement, and the consequences on object substitutability. This entails the development of suitable instruments for converting temporal values from a granularity to another.
      196
  • Publication
    Contexts as explicit parameterization of ontology driven methods
    (Consiglio Nazionale delle Ricerche. Istituto di Matematica Applicata e Tecnologie Informatiche, 2007)
    Albertoni, Riccardo 
    ;
    Camossi, Elena 
    ;
    De Martino, Monica 
    ;
    Giannini, Franca 
    ;
    Monti, Marina 
    In the recent Computer Science literature, contexts have been proposed mainly to formalize context dependent background knowledge. In this paper we discuss the importance of the application of contexts as explicit parametrization of methods exploiting the knowledge encoded in ontologies. We propose a context formalization suitable to improve the flexibility of ontology driven methods like semantic similarity and granularity. Herein, we detail in particular the context parametrization for semantic granularity. The user scenario pertaining to the exploitation of a repository for industrial design product models is discussed to illustrate the proposed formalization.
      198
  • Publication
    Adaptive management of multigranular spatio-temporal object attributes
    (Purdue University. Center for Education and Research in Information Assurance and Security, 2009-04-08)
    Camossi, Elena 
    ;
    Bertino, Elisa 
    ;
    Guerrini, Giovanna 
    ;
    Bertolotto, Michela 
    In applications involving spatio-temporal modelling, granularities of data may have to adapt according to the evolving semantics and significance of data. To address such a problem, 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 performed at run-time. The event, the condition and the action may refer to a period of time and a geographical area. Periodic evolutions may be specified, referring to both transaction and valid time dimensions. The evolution may also be constrained by the attribute values. Evolutions greatly enhance flexibility in multigranular spatio-temporal data handling but require revisiting the notion of object consistency with respect to class definitions and access to multigranular object values.
      368