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Abstrakty
Answers to queries in terms of abstract objects are defined in the logical framework of first order predicate calculus. A partial algebraic characterisation of the supremum and of the infimum of abstract answers is given in an extended Relational Algebra of the Cylindric Algebra kind. Then, the form of queries is restricted in order to be able to compute answers without the cylindrification operator. For these restricted queries we give a technique to compute an upper bound and a lower bound of abstract answers using only the operators of the standard Relational Algebra.
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Tom
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1--15
Opis fizyczny
Bibliogr. 11 poz.
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autor
- ONERA Toulouse, France, Robert.Demolombe@cert.fr
Bibliografia
- [1] Demolombe, R.: Syntactical Characterization of a Subset of Domain Independent Formulas, Journal of ACM, 1982.
- [2] Demolombe, R.: Abstract objects to represent large answers to queries in a concise form, Advances in Soft Computing. Flexible Query Answering Systems (H. Larsen, J. Kacprzyk, S. Zadrozny, T. Andreasen, H. Christiansen, Eds.), Physica-Verlag, 2001.
- [3] Ellman, T.: Approximation and Abstraction Techniques for Generating Concise Answers to Database Queries, Proc. of AAAI Spring Symposium, 1995.
- [4] Green, J., Horne, N., Orlowska, E., Siemens, P.: A rough set model of information retrieval, Fundamenta Informaticae, 28, 1996, 273-296.
- [5] Imielinski, T.: Domain abstraction and limited reasoning, Proc. of the 10th IJCAI, 1987.
- [6] Imielinski, T., Lipski, W.: The Relational model of data and cylindric algebras, Technical Report 446, Institue of Computer Science, Polish Academy of Science, 1981.
- [7] Nicolas, J.-M.: Logic for improving integrity checking in Relational Data Bases, Acta Informatica, Vol 18(Num 3), 1982.
- [8] Paola, R. A. D.: The recursive unsolvability of the decision problem for the class of Definite Formulas, Journal of ACM, 16(2), 1969.
- [9] Pawlak, Z.: Rough sets: theoretical aspects of reasoning about data, Kluwer, 1991.
- [10] Reiter, R.: Towards a logical reconstruction of relational database theory, in: On Conceptual Modelling: Perspectives from Artificial Intelligence, Databases and Programming Languages, Springer Verlag, 1983.
- [11] Ullman, J. D.: Principles of Database Systems, Computer Science Press, 1980
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BUS2-0004-0141