367 research outputs found
L’impact des externalités de réseau sur le processus de décision du consommateur.
Le concept des externalités de réseau est largement utilisé par les économistes. Il est cependant lié aux seuls produits dits de réseau. En marketing, ce concept dépasse le cadre des produits de réseau pour s’appliquer à d’autres catégories de produits. La dominance du réseau dans l’économie actuelle, nous oblige à s’intéresser à l’impact des externalités sur le comportement du consommateur. Cette présente contribution vise ainsi à examiner les conséquences de la présence des externalités sur les diverses étapes du processus de décision du consommateur.comportement du consommateur; externalités de réseau;
DEEP CONVOLUTIONAL NEURAL NETWORK USING A NEW DATASET FOR BERBER LANGUAGE
Currently, Handwritten Character Recognition (HCR) technology has become an interesting and immensely useful technology. It has been explored with highperformance in many languages. However, a few HCR systems are proposed for the Amazigh (Berber) language. Furthermore, the validation of any Amazighhandwritten recognition system remains a major challenge due to no availability of a robust Amazigh database. To address this problem, we first created two new datasets for Tifinagh and Amazigh Latin characters, by extending the well-known EMNIST database with the Amazigh alphabet. And then, we have proposed a handwritten character recognition system, which is based on a deep convolutional neural network to validate the created datasets. The proposed CNN has been trained and tested on our created datasets, and the experimental tests show that it achieves satisfactory results in terms of accuracy and recognition efficiency
Measuring Qualities for OSGi Component-Based Applications
International audienceComponent-based software engineering (CBSE) begins to reach a certain level of maturity. Indeed, for the development of complex applications the use of component paradigm has become common. Therefore, the evaluation of the quality of these applications becomes necessary. In this context, the use of metrics is considered very important. Several metrics specific to component-based applications have been proposed. However, any of these metrics gained the consensus of the CBSE community and mainly there is no proposed tool to support them. As a large part of frameworks for component-based application development is based on object-oriented technology, we propose to use some object-oriented (OO) metrics to evaluate component-based applications produced with this kind of framework. Indeed, these metrics became a standard in OO community. So, they are well-defined, well-known and empirically validated. To identify which object-oriented metrics are useful for the evaluation of component-based applications, we have conducted an experimental study on 10 OSGi applications. This study also gives us the opportunity to discuss on the respect by OSGi developers of some properties pointed out by the literatur
Comparative Histological Study on the Algerian Thymus Ciliatus at Different Phenological Stages
The aim of the current study was to compare the histological observations of stems, leaves, and different secretory structures of Thymus ciliatus at three phenological stages. The anatomical observations of stems, leaves, and glandular trichomes were carried out by light microscopy. The results showed that phenological stages do not affect significantly the anatomical, whereas there was a significant increase in secretory trichomes. The glandular trichomes are distributed on the surface of the stems and the leaves. There are only two distinct types of secretory trichomes, Peltate consisting of a basal cell, a stalk cell, and an 8-celled head type, which are distributed more diffusely on the leaf than on the stem, while capitate trichomes were present only on the surface stem samples. Accumulation of essential oils varies according to the seasons with high sizes of trichomes secretory at the flowering period
ESA PetriNet: Petri net Based Tool for Reliability Analysis
International audienceThis paper describes the critical (feared) scenarios derivation tool ESA PetriNet (Extraction Scenarios Algorithm from Petri Net) available from : http://www.laas.fr/ESA. ESA PetriNet allows to derive scenarios leading to critical (feared) situation in embedded systems. The system model is given by a Petri net. To derive critical scenarios and to avoid the state space explosion, the solution is to use directly the Petri net model. Linear logic (which does not appears in this paper)offers a theoretical framework to interpret the Petri net model and to extract the scenarios. ESA PetriNet provides all minimal scenarios which contain strictly necessary and sufficient events to reach a specified state. ESA PetriNet can be used with classical Petri net modelling or in its objects oriented version
Software Architecture Constraints as Customizable, Reusable and Composable Entities
International audienceOne of the major advantages of component-based software engineering is the ability for developers to reuse and assemble software entities to build complex software. Whereas decomposition of software into components has been and is largely addressed for what concerns the business (functional) part of applications, this is not yet the case for what concerns their documentation (non-functional) part. In this pa- per, we propose a new and original solution to express component-based software non-functional documentation, and we will focus more espe- cially on architecture constraints, which formalize parts of architecture decisions, as executable, customizable, reusable and composable build- ing blocks represented by components. Component-based applications using business and constraint components can be modeled with CLACS, a dedicated ADL which is also introduced in the paper. Architecture constraints can be executed at design-time within CLACS. CLACS is implemented as a plugin in the Eclipse IDE
CROSS-TALK BETWEEN RAL AND RAC PATHWAYS IN THE CONTROL OF CELL MIGRATION
SUMMARY (English)
Very little is known about the coordination and the integration among the different regulators of the motility process. This work deals with two migration-regulatory pathways: the Rac1/WRC (Wave Regulatory Complex) pathway that drives the formation of the actin polymerization network at the front of motile cells; and RalB/exocyst pathway for which the molecular mechanisms underlying its implication in cell motility were still largely unknown at the beginning of this thesis. Rac1 and RalB are small GTPases of the Rho and Ras family, respectively. WRC and exocyst complexes are their direct effectors.
In searching for connections between the exocyst and migration regulators, we found that two subunits of the exocyst, Exo70 and Sec6, interact directly in vitro with two subunits of the WRC, Abi and Cyfip, respectively. Moreover, we found that exocyst subunits can interact in vitro with the whole fully-assembled WRC complex. We also showed that these two complexes associate in vivo. Functionally, the exocyst was required for WRC complex positioning at the front of migrating cells.
On the other hand, we also found that two other subunits of the exocyst, Sec8 and Exo84, interact with SH3BP1 (a RhoGAP protein) by two-hybrid assay and by co-immunoprecipitation. SH3BP1 localizes at the leading edge and this localization is dependent on the exocyst. Interestingly, in vivo, the RalB/exocyst/SH3BP1 pathway specifically targets Rac1, and not Cdc42. By a combination of approaches we concluded that SH3BP1 is required to inactivate Rac1 at the front.
In our model we propose that RalB/exocyst regulates cell migration by driving to the leading edge two key signaling elements of the Rac1 pathway: its effector WRC, that stimulates actin filament nucleation, and its negative regulator SH3BP1, a GAP promoting Rac1 inactivation and GDP/GTP cycling. In conclusion, this work provides novel molecular and functional links between polarized exocytosis and actin dynamics during cell motility
Application des techniques d’oxydation avancée pour la dépollution des effluents organiques dans les eaux de rejets industriels : cas des savonneries
Within the framework of the destruction of refractory organics contained in a complex aqueous matrix, the advanced oxidation processes appear to be a first class technology. So this survey is dedicated to the sonolysis and the photolysis of two organics, namely the naphthol blue black (an acid azo-dye, hydrophilic, noted NBB) and the nonylphenol (a detergent, hydrophobic et volatile, noted NP), single or in competition. High frequency (278 kHz) ultrasound is found to be efficient. NBB decolorization is effective within 180 min and its mineralization reaches 23% while NP is degraded for 120 min. Different parameters were studied, such as ultrasound power, substrate concentration, pH, inorganic ions (bicarbonate and phosphate), and competition. In the NBB/NP mixture, NBB has no influence on the NP degradation whereas NP has a strong effect on the NBB decolorization. Nevertheless, the presence of bicarbonate ions in the mixture reduces the negative effect of NP, thanks to the formation of carbonates radicals. Direct photolysis is the topic of the second part of this study, so as to make a comparison of these two oxidative techniques. It was emphasizes that sonolysis is most adapted for the treatment of more concentrated pollutant, because of the intense production of HO• radicals. Moreover sonolysis is relevant when inorganic ions are present in the mixture, in order to minimize the competition between organics. Then the efficiency of different AOP was tested for the two target pollutants; results can be organized according the following: UV < UV/H2O2 < Fe2+/H2O2 < UV/Fe2+/H2O2.Dans le cadre de l'élimination de composés réfractaires contenu dans une matrice complexe, les procédés d'oxydation avancée s'avèrent être une technologie de choix. Cette étude est donc consacrée à la sonolyse et à la photolyse de deux xénobiotiques organiques, le naphthol blue black (un colorant hydrophile, noté NBB) et le nonylphénol (un détergent, hydrophobe et volatil, noté NP), seuls ou en compétition. L'efficacité de la technique ultrasonore de haute fréquence (278 kHz) a été testée sur les molécules cibles et leur mélange. La décoloration du NBB est effective après 180 min de traitement et s'accompagne d'une minéralisation de 23% alors que le NP se dégrade après 120 min. L'effet des paramètres a été étudié, tels que la puissance ultrasonore, la concentration du substrat, le pH, les ions inorganiques (bicarbonates et phosphates) et la compétition. Ainsi dans le mélange, la présence du NBB n'a pas d'influence sur la disparition sur NP tandis que la décoloration du NBB est affectée par la présence du NP. Cependant, la présence des ions bicarbonates dans le mélange permet par l'intermédiaire des radicaux carbonates de contrebalancer l'effet inhibiteur du NP. L'utilisation de la photolyse directe a fait l'objet de la deuxième partie de ce travail, ce qui a permis de faire une étude comparative des deux techniques. Il a été montré que la sonochimie, fort de sa capacité à produire abondamment les radicaux HO•, est plus adaptée au traitement des effluents relativement plus concentrés. De plus, la sonochimie permet de mettre en valeur les ions inorganiques, constituants naturels de l'eau pour minimiser l'effet inhibiteur de la matrice. Ensuite, l'efficacité de certains Procédés d'Oxydation Avancée (POA) sur l'élimination des xénobiotiques sus-mentionnés a été testée et les résultats obtenus ont donné lieu à l'ordre suivant : UV < UV/H2O2 < Fe2+/H2O2 < UV/Fe2+/H2O2
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