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Language of Preference Formulae
Nedbal, Radim
There is a need for handling preferences in relational query languages that arises naturally in real-world applications dealing with possible choices generated by the current state of the world captured in the relational data model. To address this problem, we propose a fully declarative language for encoding preferences conditional on the current state of the world represented as a relation database instance. Being based purely on the qualitative type of information about the preference model, the language is intuitive and leads to a exible approach for specifying the most desirable choices of autonomous systems that act on behalf of their designers. Throughout the paper, we use an example of a control support system for a bank surveillance to motivate the need for our framework and to illustrate it.
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Ontologický přístup k integraci geografických dat
Linková, Zdeňka ; Nedbal, Radim
A key point in modern automated data processing is metadata semantics representation. Employing Semantic Web existing features - ontologies - is a promising option. Ontologies open a novel approach to knowledge representation. The paper presents a GIS (Geographic Information System) domain application illustrating ontological approach to data integration and data processing automation in the specific system. This VirGIS system is an integration system that works with spatio-temporal data. We start our study with developing the data representation based on common Semantic Web techniques and build a VirGIS ontology.
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Obecný relační datový model s preferencemi
Nedbal, Radim
The aim of the paper is to present a novel, general approach to preference modelling in the framework of the relational data model. To allow nonmonotonic operations, the preferences are defined between sets of relational instances. The aim is the generalization of the relational algebra that is as minimal as possible, in the sense that the formal fundamentlas of the relational data model are preserved. At the same time, the extended model should be formal enough to provide a sound basis for the investigation of other new preference constructors and operations and for new possible applications.
Plný tet:  PDF
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Relační model dat s uspořádáním
Nedbal, Radim
The paper proposes to extend the classical relational data model by the notion of preference realized through a partial ordering on the set of relation instances. The extension involves not only data representation but also data manipulation.
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