Search results for "Logic in computer science"
showing 10 items of 129 documents
Negative results in the theory of games with lexicographic utilities
2003
When players may have lexicographic utilities, there are: (i) extensive games having a non-empty set of equilibria but empty sets of sequentially rational, sequential and perfect equilibria (ii) normal form games having a non-empty set of equilibria but an empty set of proper equilibria and no stable set of equilibria and (iii) two extensive games having the same normal form representation and disjoint sets of sequential equilibria.
Reasoning with Vague Spatial Information from Upper Mesopotamia (2000BC)
2015
International audience; Concepts such as near, far, south of, etc., are by its own nature vague. However, they are quite common in human language. In the case of historical records, these concepts are often the only source of information regarding the position of ancient places whose exact location has been lost. In our research, we use digitized written records from Upper Mesopotamia (2000BC) from the HIGEOMES project. Our goal is to provide better understanding of the location of places, based on the analysis of spatial statements. In our approach, we analyse cardinal statements between places with known location. Using this information we construct a probabilistic function representing t…
Extending SPARQL with Temporal Logic
2009
The data integration and sharing activities carried on in the framework of the Semantic Web lead to large knowledge bases that must be queried, analyzed, and exploited efficiently. Many of the knowledge representation languages of the Semantic Web, starting with RDF, are based on directed, labeled graphs, which can be also manipulated using graph algorithms and tools coming from other domains. In this paper, we propose an analysis approach of RDF graphs by reusing the verification technology developed for concurrent systems. To this purpose, we define a translation from the SPARQL query language into XTL, a general-purpose graph manipulation language implemented in the CADP verification too…
FOWLA, A Federated Architecture for Ontologies.
2015
International audience; The progress of information and communication technologies has greatly increased the quantity of data to process. Thus, managing data heterogeneity is a problem nowadays. In the 1980s, the concept of a Federated Database Architecture (FDBA) was introduced as a collection of components to unite loosely coupled federation. Semantic web technologies mitigate the data heterogeneity problem, however due to the data structure heterogeneity the integration of several ontologies is still a complex task. For tackling this problem, we propose a loosely coupled federated ontology architecture (FOWLA). Our approach allows the coexistence of various ontologies sharing common data…
Representing and Reasoning for Spatiotemporal Ontology Integration
2004
International audience; The World-Wide Web hosts many autonomous and heterogeneous information sources. In the near future each source may be described by its own ontology. The distributed nature of ontology development will lead to a large number of local ontologies covering overlapping domains. Ontology integration will then become an essential capability for effective interoperability and information sharing. Integration is known to be a hard problem, whose complexity increases particularly in the presence of spatiotemporal information. Space and time entail additional problems such as the heterogeneity of granularity used in representing spatial and temporal features. Spatio-temporal ob…
Some Computational Aspects of DISTANCE-SAT
2007
In many AI fields, one must face the problem of finding a solution that is as close as possible to a given configuration. This paper addresses this problem in a propositional framework. We introduce the decision problem distance-sat, which consists in determining whether a propositional formula admits a model that disagrees with a given partial interpretation on at most d variables. The complexity of distance-sat and of several restrictions of it are identified. Two algorithms based on the well-known Davis/Logemann/Loveland search procedure for the satisfiability problem sat are presented so as to solve distance-sat for CNF formulas. Their computational behaviors are compared with the ones …
How to Enrich Description Logics with Fuzziness
2017
International audience; The paper describes the relation between fuzzy and non-fuzzy description logics. It gives an overview about current research in these areas and describes the difference between tasks for description logics and fuzzy logics. The paper also deals with the transformation properties of description logics to fuzzy logics and backwards. While the process of transformation from a description logic to a fuzzy logic is a trivial inclusion, the other way of reducing information from fuzzy logic to description logic is a difficult task, that will be topic of future work.
Continuum : un modèle spatio-temporel et sémantique pour la découverte de phénomènes dynamiques au sein d’environnements géospatiaux
2015
There is a need for decision-makers to be provided with both an overview of existing knowledge, and information which is as complete and up-to-date as possible on changes in certain features of the biosphere. Another objective is to bring together all the many attempts which have been made over the years at various levels (international, Community, national and regional) to obtain more information on the environment and the way it is changing. As a result, remote sensing tools monitor large amount of land cover informations enabling study of dynamic processes. However the size of the dataset require new tools to identify pattern and extract knowledge. We propose a model to discover knowledg…
Multi-Domain Retrieval of Geospatial Data Sources Implementing a Semantic Catalogue
2015
International audience; Nowadays, the expertise of a user plays an important role in the search and retrieval in the information systems that usually combines general and specialized knowledge in the construction of queries. In addition, most of the queries systems are currently restricted on specific domains. Tackling these issues, we propose a methodology that implements a semantic catalogue in order to provide a smart queries system for retrieving data sources on the web by means of the extension of the user expertise. We propose the combination of a query expansion method, and the use of similarity measures and controlled vocabularies. Thus, it allows the system to recommend data source…
Multidimensional Land Cover Change Analysis using Vector Change and Land Cover Taxonomies
2015
International audience; Around the world, land cover changes occur due to natural and anthropogenic factors. In many cases, the consequences of anthropogenic interventions are unexpected. In order for scientists and policy makers to identify land cover change processes of interest, it is necessary suitable tools for early and efficient analysis of land cover data. In our research, we present a data model that makes use of semantic web technologies to manage a hierarchical structure of land cover types. Using this approach, it is possible to manage the land cover information at different levels of abstraction. In our research, we use a Change Vector Analysis approach to represent the land co…