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Bakhtouchi A.,Ecole Nationale Superieure dInformatique ESi
Recent Patents on Computer Science | Year: 2015

With the development of new technologies of information and communication, more and more data sources are available. The diversity, distribution and heterogeneity of these sources make their access a real issue. Data integration systems allow a unified and transparent access to heterogeneous data sources giving the illusion to user that he is accessing only one source. A query over the global schema of a data integration system is rewritten into the union of sub-queries over sources. But obviously, not all sources contain necessary answer to the posed query and querying such sources is a loss of time. To optimize queries on an integration system, we propose in this patent paper, to associate (annotate) to each numeric or enumerated property, the domain of values of this property in the source. We group together and merge domains into subdomains. A set of sources is assigned to each sub-domain. We store these sub-domains and linked sources (annotations) at the mediator. Consequently, a query having a predicate on one of these annotated properties will be checked before sending to a source. If the source does not contain instances that satisfy the predicate, this source is removed from the concerned sources. Our patent proposition is evaluated on a set of generated databases and the experimental results show a clear improvement in the queries execution time. © 2015 Bentham Science Publishers.

Bakhtouchi A.,Ecole Nationale Superieure dInformatique ESi | Bellatreche L.,CNRS Laboratory of Computer Science and Automatic Control Systems | Jean S.,CNRS Laboratory of Computer Science and Automatic Control Systems | Ait-Ameur Y.,CNRS Toulouse Institute in Information Technology
International Journal of Web and Grid Services | Year: 2012

Providing automatic integration solutions is the key to the success of applications managing massive amounts of data. Two main problems stand out in the major studies: i the management of the source heterogeneity ii the reconciliation of query results. To tackle the first problem, formal ontologies are used to explicit the semantic of data. The reconciliation problem consists in deciding whether different identifiers refer to the same instance. Two main trends emerge in the reconciliation process: i the assumption that different source entities representing the same concept have the same key - a strong hypothesis that violates the autonomy of sources. ii The use of statistical methods that identify affinities between concepts - not suitable for sensitive-applications. In this paper, we propose a methodology integrating sources referencing shared domain ontology enriched with functional dependencies (FD). The presence of FD gives more autonomy to sources when choosing their primary keys and allows deriving a reconciliation key for a given query. The methodology is then validated using LUBM. Copyright © 2012 Inderscience Enterprises Ltd.

Belguechi R.,Ecole Nationale Superieure dInformatique ESi | Lacharme P.,National Engineering School of Caen | Rosenberger C.,National Engineering School of Caen
International Journal of Information Technology and Management | Year: 2012

We address in this paper the problem of privacy in the current architecture in electronic passports for the storage and transmission of biometric data such as fingerprints. The current architecture provides a good protection of biometric personal data but brute force attack could be used in the near future using cloud computing. We propose a new solution combining cryptographic protocols and cancellable biometrics to solve this problem. The biocode of an individual is protected by cryptographic keys exchanged by the PACE protocol. We put into obviousness the benefit of the proposed solution in terms of security and privacy. Copyright © 2011 Inderscience Enterprises Ltd.

Temglit N.,Ecole Nationale Superieure dInformatique ESi | Nacer M.A.,University of Science and Technology Houari Boumediene
2012 IEEE Conference on Open Systems, ICOS 2012 | Year: 2012

As more web services can be used over the Internet, the need to find and combine dynamically efficient services to fulfill a given goal becomes an important and challenging task. To this end, we are interested particularly in dynamic approaches for web service composition. In contrast to the static ones, a composition of services is called dynamic if participant services are selected and composed on the fly based on the needs formulated by the user and the availability of published services. We propose in this work, a flow-graph based system for service composition and composite service discovery to satisfy a functional need of a given query. The idea is to model all the possible connections between published services as Output-Input semantic matching. These established connections are stored in a graph called precedence graph in order to retrieve dynamically, all possible plans that could answer a given query. © 2012 IEEE.

Issad M.,Algerian Center de Developpement des Techniques Avancees | Anane M.,Ecole Nationale Superieure dInformatique ESi | Anane N.,Algerian Center de Developpement des Techniques Avancees
International Journal of High Performance Systems Architecture | Year: 2011

In this paper, the algorithm and the hardware implementation of radix-2 Montgomery modular multiplication (MMM) are presented. The operation's performances depend on the radix and the modulus size. The MMM with big modulus requires a large area for its implementation. The objective of this work is to realise an optimised intellectual property (IP) to perform this operation with a reduced area, independent of the modulus size, dedicated to low rate cryptographic applications. Our architecture uses a fixed data path size w to compute the MMM of two n-bits operands, with n w. To store these operands, we use embedded memory blocks (SelectRam), instead of long registers to overcome the routing complexity which is a timing consumer. The arithmetic unit (AU) is optimised at the low level (CLB), resulting in high performances AU. The proposed architecture is suitable to hybrid cryptosystem where both the symmetric and asymmetric cryptographies are used. © 2011 Inderscience Enterprises Ltd.

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