Browsing Περιοδικά, εφημερίδες by Author "Γεργατσούλης, Μανώλης"

Now showing items 21-30 of 30

    • A semantic mapping of VRA Core 4.0 to the CIDOC conceptual reference model 

      Γεργατσούλης, Μανώλης; Γαϊτάνου, Πανωραία; Gergatsoulis, Manolis; Gaitanou, Panorea (2011)
      In the recent decades, we have witnessed a tremendous proliferation of metadata schemas, particularly in the cultural heritage domain. As a consequence, there is a growing need to integrate these schemas to solve a number ...

    • Storing multidimensional XML documents in relational databases 

      Γεργατσούλης, Μανώλης; Φουστέρης, Νικόλαος; Σταύρακας, Γιάννης; Gergatsoulis, Manolis; Fousteris, Nikolaos; Stavrakas, Yannis (2007)
      The problem of storing and querying XML data using relational databases has been considered a lot and many techniques have been developed. MXML is an extension of XML suitable for representing data that assume different ...

    • Temporal disjunctive logic programming 

      Γεργατσούλης, Μανώλης; Ροντογιάννης, Παναγιώτης; Παναγιωτόπουλος, Θέμης; Gergatsoulis, Manolis; Rondogiannis, Panos; Panayiotopoulos, Themis (2001)
      In this paper we introduce the logic programming language Disjunctive Chronolog which combines the programming paradigms of temporal and disjunctive logic programming. Disjunctive Chronolog is capable of expressing dynamic ...

    • Temporal stratification tests for linear and branching-time deductive databases 

      Γεργατσούλης, Μανώλης; Ροντογιάννης, Παναγιώτης; Νομικός, Χρίστος; Gergatsoulis, Manolis; Rondogiannis, Panos; Nomikos, Christos (2005)
      We consider the problem of extending temporal deductive databases with stratified negation. We argue that the classical stratification test for deductive databases is too restrictive when one shifts attention to the temporal ...

    • A transformation technique for datalog programs based on non-deterministic constructs 

      Γεργατσούλης, Μανώλης; Ροντογιάννης, Παναγιώτης; Ποτίκας, Πέτρος; Gergatsoulis, Manolis; Rondogiannis, Panos; Potikas, Petros (2001)
      Recently, a novel transformation technique for Datalog programs, called the branching-time transformation, was introduced by the authors. In this paper we propose a significant extension of the branching-time transformation ...

    • Unfold/fold transformations for disjunctive logic programs 

      Γεργατσούλης, Μανώλης; Ροντογιάννης, Παναγιώτης; Gergatsoulis, Manolis; Rondogiannis, Panos (1997)
      Unfold/fold transformation rules for disjunctive logic programs are proposed in this paper. Our transformation rules preserve the meaning of the programs.

    • Union rewritings for XPath fragments 

      Γεργατσούλης, Μανώλης; Αφράτη, Φώτο; Damigos, M.; Gergatsoulis, Manolis; Afrati, Foto (2011)
      In this paper, we study the problem of finding an equivalent rewriting of an XPath query using multiple views, and we show that the union operator may be required in order to find such a rewriting. In particular, focusing ...

    • Updating multidimensional XML documents 

      Γεργατσούλης, Μανώλης; Gergatsoulis, Manolis (2008)
      Purpose-In a wide spectrum of applications, it is desirable to manipulate semistructured information that may present variations according to different circumstances. Multidimensional XML (MXML) is an extension of XML ...

    • A value-propagating transformation technique for Datalog programs based on non-deterministic constructs 

      Γεργατσούλης, Μανώλης; Ροντογιάννης, Παναγιώτης; Ποτίκας, Πέτρος; Gergatsoulis, Manolis; Rondogiannis, Panos; Potikas, Petros (2006)
      The branching-time transformation is a recent technique for optimizing Chain Datalog programs. In this paper we propose a significant extension of the branching-time transformation which we believe opens up a promising new ...

    • View selection for real conjunctive queries 

      Αφράτη, Φώτο; Γεργατσούλης, Μανώλης; Παυλάκη, Βάσια; Chirkova, Rada; Afrati, Foto; Gergatsoulis, Manolis; Pavlaki, Vassia (2007)
      Given a query workload, a database and a set of constraints, the view-selection problem is to select views to materialize so that the constraints are satisfied and the views can be used to compute the queries in the workload ...