Anticipation of ETX Metric to manage Mobility in Ad Hoc Wireless Networks

International audienceWhen a node is moving in a wireless network, the routing metrics associated to its wireless links may reflect link quality degrada- tions and help the routing process to adapt its routes. Unfortunately, an important delay between the metric estimation and its inclusion in the routing process makes this approach inefficient. In this paper, we intro- duce an algorithm that predicts metric values a few seconds in advance, in order to compensate the delay involved by the link quality measurement and their dissemination by the routing protocol. We consider classical metrics, in particular ETX (Expected Transmission Count) and ETT (Expected Transmission Time), but we combine their computations to our prediction algorithm. Extensive simulations show the route enhance- ment as the Packet Delivery Ratio (PDR) is close to 1 in presence of mobility

Metric Anticipation in Mobile Ad-Hoc Networks

International audienceIn this paper, we propose a new method for metric calculations. It aims to improve mobility management in wireless networks. The idea consists in anticipating metric values in order to compensate the delay generated by the measure of the link quality and the routing protocols. As an example, we consider the popular ETX (Expected Transmission Count) metric. We focus on ad-hoc networks, even if our approach could be used in other contexts. We show by simulations that our approach, when well parametrized, allows a Packet Delivery Ratio (PDR) close to 100% when nodes are moving

Poopćenje analitičkih izraza za pseudo -voigtovu funkciju koja se rabi u analizama difrakcijskih vrhova

Nous revisitons ici la théorie, utilisée en analyse des profils de raies de diffraction des rayons X et des neutrons, relative à la fonction de forme du pic dite de pseudo -Voigt (notée pV). Nous présentons une généralisation des expressions de la largeur intégrale et à mi-hauteur de la fonction pV, de la transformée de Fourier de cette fonction ainsi que du seuil du paramètre de mélange h. Nous incorporons nos résultats dans la procédure de fit, ce qui améliore les facteurs de précision.Razmatramo teoriju koja se primjenjuje u analizi linija difraktiranog rentgenskog zračenja i neutrona a odnosi se na tzv. pseudo-Voigtovu (skraćeno pV) funkciju za opis oblika vrha. Dajemo poopćenje analitičkog izraza za ukupnu širinu i širinu na pola visine vrha funkcije pV, Fourierovu transformaciju izraza, kao i prag parametra miješanja η. Primijenjujemo naš postupak za prilagodbu i postižemo poboljšanje točnosti

Poopćenje analitičkih izraza za pseudo -voigtovu funkciju koja se rabi u analizama difrakcijskih vrhova

Nous revisitons ici la théorie, utilisée en analyse des profils de raies de diffraction des rayons X et des neutrons, relative à la fonction de forme du pic dite de pseudo -Voigt (notée pV). Nous présentons une généralisation des expressions de la largeur intégrale et à mi-hauteur de la fonction pV, de la transformée de Fourier de cette fonction ainsi que du seuil du paramètre de mélange h. Nous incorporons nos résultats dans la procédure de fit, ce qui améliore les facteurs de précision.Razmatramo teoriju koja se primjenjuje u analizi linija difraktiranog rentgenskog zračenja i neutrona a odnosi se na tzv. pseudo-Voigtovu (skraćeno pV) funkciju za opis oblika vrha. Dajemo poopćenje analitičkog izraza za ukupnu širinu i širinu na pola visine vrha funkcije pV, Fourierovu transformaciju izraza, kao i prag parametra miješanja η. Primijenjujemo naš postupak za prilagodbu i postižemo poboljšanje točnosti

Mice Doubly-Deficient in Lysosomal Hexosaminidase A and Neuraminidase 4 Show Epileptic Crises and Rapid Neuronal Loss

Tay-Sachs disease is a severe lysosomal disorder caused by mutations in the HexA gene coding for the α-subunit of lysosomal β-hexosaminidase A, which converts GM2 to GM3 ganglioside. Hexa−/− mice, depleted of β-hexosaminidase A, remain asymptomatic to 1 year of age, because they catabolise GM2 ganglioside via a lysosomal sialidase into glycolipid GA2, which is further processed by β-hexosaminidase B to lactosyl-ceramide, thereby bypassing the β-hexosaminidase A defect. Since this bypass is not effective in humans, infantile Tay-Sachs disease is fatal in the first years of life. Previously, we identified a novel ganglioside metabolizing sialidase, Neu4, abundantly expressed in mouse brain neurons. Now we demonstrate that mice with targeted disruption of both Neu4 and Hexa genes (Neu4−/−;Hexa−/−) show epileptic seizures with 40% penetrance correlating with polyspike discharges on the cortical electrodes of the electroencephalogram. Single knockout Hexa−/− or Neu4−/− siblings do not show such symptoms. Further, double-knockout but not single-knockout mice have multiple degenerating neurons in the cortex and hippocampus and multiple layers of cortical neurons accumulating GM2 ganglioside. Together, our data suggest that the Neu4 block exacerbates the disease in Hexa−/− mice, indicating that Neu4 is a modifier gene in the mouse model of Tay-Sachs disease, reducing the disease severity through the metabolic bypass. However, while disease severity in the double mutant is increased, it is not profound suggesting that Neu4 is not the only sialidase contributing to the metabolic bypass in Hexa−/− mice

Etude rhéologique et bactéricide d'une pate dentifrice à base de siwak

110 p. : ill. ; 30 cmLe présent travail qui est dirigé par le prof.K.hammoudi est orienté vers la formulation d’une pate dentifrice à base de la poudre de siwak, la détermination de l’evaluation du potentiel irritant par application sur la membrane chorio-allantoïdienne de l’oeuf de poule, par HET-CAM test. Identification des différents groupes chimiques de la poudre de siwak (salvadora persica), la détermination de l’activité antibactérienne des pates dentifrices obtenus à base de la poudre de siwak à différents concentrations ainsi que les extraits de siwak. Détermination du comportement des pates dentifrices formulées par une étude rhéologiques. La détermination du potentiel irritant des pates dentifrices formulées a permis de nous montrer que la pate dentifrice est non irritante sur la membrane muqueuse a une concentratio

Difficultés d’intégration d’un quartier spontané dans une ville saharienne : le cas de Bni Ouskout à Adrar

The promotion in 1974 of the city of Adrar to the rank of chief town of wilaya has enabled it to become a real attraction of the populations thanks to its regional tertiary equipment level. Its role is reinforced by its strategic position as a border wilaya with Mali, which makes it a transitional or final target for the poor sub-Saharan populations. The oasis agglomeration consequently undergoes profound transformations. Its urban settlements are today composed of a great diversity of spatial entities whose characteristics depend, for some, on the urban policies initiated by the state at the time of their construction, while the others are the product of “spontaneous”, urbanization such as the neighborhood of Bni Ouskout. The latter has developed not far from the center of Adrar, the actors of its production being mainly made up of social groups from distant areas (Touaregs). It is a large “spontaneous” and “irregular” neighborhood, with socio-economic, morphological and relational components quite different from other neighborhoods in the city. It constitutes a socio-spatial margin which local authorities are struggling to restructure because of lack of cooperation of its inhabitants. The resistance shown by the inhabitants to the restructuring project is due to the fact that many of them would be forced to modify their practices, such as those related to their occasional residence and their “transit” situation, which would jeopardize the functioning of informal activities