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Boriskin A.V.,Ukrainian Academy of Sciences | Boriskin A.V.,University Europeenne Of Bretagne | Vorobyov A.,University of Rennes 1 | Sauleau R.,University of Rennes 1
European Microwave Week 2010, EuMW2010: Connecting the World, Conference Proceedings - European Microwave Conference, EuMC 2010 | Year: 2010

The paper describes a procedure for designing two-shell circularly-layered dielectric lens antennas (DLA) with radiation characteristics compatible with conventional multi-layer uniformly-layered Luneburg lens (LL) antennas. It is demonstrated that a two-shell lens with the favorable collimating capabilities can be designed using standard low-permittivity materials provided the proper selection of shells thickness. Analysis is performed in the 2-D formulation using the exact Mie-type series approach. The outlined recommendations are then validated on the example of two-shell spherical DLAs excited by a horn antenna modelled using commercial software. © 2010 EuMA. Source

Abraham M.,Telecom Bretagne | Abraham M.,University Europeenne Of Bretagne | Abraham M.,University of Paris Pantheon Sorbonne
Proceedings of the 24th International Florida Artificial Intelligence Research Society, FLAIRS - 24 | Year: 2011

This paper presents a discussion about assistive and augmentative natural language processing designed for certain disabled persons unable to communicate. Several approaches have been proposed, according to abilities of the writer. Here we distinguish two cases in the writer's capacities: the writer knows alphabetic writing, or (s)he does not know it. In the first case, the idea is to assist the writer by completing the words or the group of words which are initially written. In the second case, pictograms are used instead of characters, but it must be decided if these pictograms represent concepts or words in a new writing system. If the pictograms represent concepts, the produced text may not correspond exactly to the wishes of the writer; whereas when the pictograms represent words, the writer has to change his (her) mental approach to write the words that (s)he has chosen in another way. Copyright © 2011, Association for the Advancement of Artificial Intelligence. All rights reserved. Source

Amphawan K.,Chulalongkorn University | Surarerks A.,Chulalongkorn University | Lenca P.,Telecom Bretagne | Lenca P.,University Europeenne Of Bretagne
3rd International Conference on Knowledge Discovery and Data Mining, WKDD 2010 | Year: 2010

Temporal periodicity of itemset appearance can be regarded as an important criterion for measuring the interestingness of itemsets in several application. A frequent itemset can be said periodic-frequent in a database if it appears at a regular interval given by the user. In this paper, we propose a concept of the approximate periodicity of each itemset. Moreover, a new tree-based data structure, called ITL-tree (Interval Transaction-ids List tree), is proposed. Our tree structure maintains an approximation of the occurrence information in a highly compact manner for the periodicfrequent itemsets mining. A pattern-growth mining is used to generate all of periodic-frequent itemsets by a bottomup traversal of the ITL-tree for user-given periodicity and support thresholds. The performance study shows that our data structure is very efficient for mining periodic-frequent itemsets with approximate periodicity results. © 2010 IEEE. Source

Favier L.,National Graduate School of Chemistry, Rennes | Favier L.,University Europeenne Of Bretagne | Simion A.I.,University of Bacau | Rusu L.,University of Bacau | And 4 more authors.
Environmental Engineering and Management Journal | Year: 2015

The present work systematically investigates the photocatalytic degradation of carbamazepine (CBZ), an organic compound, known as refractory to the conventional wastewater treatment by the titanium dioxide PC 500 catalyst. The effects of some fundamental operating parameters in heterogeneous photocatalysis were investigated in this work in order to determine the main ones affecting the degradation kinetics. The obtained results clearly showed that the removal rate of the target compound is strongly influenced by the initial concentration of the pollutant. The degradation reaction rate increases when the concentration of CBZ decreases due to a lower OH·/CBZ ratio. On the other hand, it was shown that during the first 30 minutes the reaction of photocatalytic degradation follows a first order kinetic and also that when the incident light flux increases, the photocatalytic degradation process is accelerated due to the increases of the catalyst excitation probability with sufficient photon energy. A relatively high CBZ removal yield (of about 87%) was obtained for an initial pollutant concentration of 2 mg/L and an irradiation time of 150 min. A total organic carbon (TOC) reduction of about 74% was observed confirming the mineralization of the parent compound under UV light conditions. As expected, it was observed that the effect of TiO2 concentration on the degradation kinetics was significant confirming the positive influence of the increased number of TiO2 active sites on the process. Finally, the Langmuir-Hinshelwood (L-H) model was successfully used to fit the experimental results and the L-H model constants were also calculated. Source

Le Gall B.,University Europeenne Of Bretagne | Daoud M.A.,CNRS Institute of Earth Sciences | Maury R.C.,University Europeenne Of Bretagne | Rolet J.,University Europeenne Of Bretagne | And 2 more authors.
Journal of Structural Geology | Year: 2010

The Ali Sabieh Range, SE Afar, is an antiform involving Mesozoic sedimentary rocks and synrift volcanics. Previous studies have postulated a tectonic origin for this structure, in either a contractional or extensional regime. New stratigraphic, mapping and structural data demonstrate that large-scale doming took place at an early stage of rifting, in response to a mafic laccolithic intrusion dated between 28 and 20 Ma from new K-Ar age determinations. Our 'laccolith' model is chiefly supported by: (i) the geometry of the intrusion roof, (ii) the recognition of roof pendants in its axial part, and (iii) the mapping relationships between the intrusion, the associated dyke-sill network, and the upper volcanic/volcaniclastic sequences. The laccolith is assumed to have inflated with time, and to have upwardly bent its sedimentary roof rocks. From the architecture of the ~1 km-thick Mesozoic overburden sequences, ca. 2 km of roof lifting are assumed to have occurred, probably in association with reactivated transverse discontinuities. Computed paleostress tensors indicate that the minimum principal stress axis is consistently horizontal and oriented E-W, with a dominance of extensional versus strike-slip regimes. The Ali Sabieh laccolith is the first regional-scale magma-driven antiform structure reported so far in the Afro-Arabian rift system. © 2010 Elsevier Ltd. Source

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