362 research outputs found
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Determinants Socio-Economiques de lâadoption des Modes de Vente de la Noix dâanacarde dans les Communes de Djougou, Tchaourou et Glazoue au Benin
Le souci de la sĂ©curisation du revenu amĂšne les exploitants producteurs dâanacarde du BĂ©nin Ă multiplier les modes de commercialisation (vente individuelle, vente groupĂ©e et vente mixte). Lâobjectif de cet article est de ressortir les indicateurs socio-Ă©conomiques qui orientent le choix du mode de vente de la noix dâanacarde par les producteurs des Communes de Djougou, Tchaourou et GlazouĂ©. LâApproche mĂ©thodologique est basĂ©e sur un questionnaire semi-structurĂ© adressĂ© Ă 383 exploitants producteurs dâanacarde, sĂ©lectionnĂ©s de maniĂšre alĂ©atoire simple dans les Communes de Tchaourou, Djougou et GlazouĂ©. Cet Ă©chantillon est rĂ©parti en trois (03) sousunitĂ©s dâobservation : 222 exploitants adoptant la vente individuelle, 100 exploitants adoptant la vente groupĂ©e et 61 exploitants adoptant la combinaison des deux modes prĂ©cĂ©dents selon la formule dâĂ©chantillonnage de Dagnelie. Lâanalyse a Ă©tĂ© rĂ©alisĂ© au moyen dâune rĂ©gression logistique ayant permis de ressortir les facteurs discriminant le choix des modes de vente. Les rĂ©sultats issus des analyses ont montrĂ© que lâĂ©chantillon considĂ©rĂ© est dominĂ© par les hommes (84,6%) nâayant aucun niveau dâinstruction (62,4%), pratiquant lâagriculture comme Ă©tant la principale activitĂ© (82,2%). La vente individuelle est pratiquĂ©e par 58% des exploitants de lâĂ©chantillon. Ce mode rĂ©munĂšre Ă un prix variant de 350 Ă 900 F CFA/Kg, sachant que 1 Euro Ă©quivaut Ă 655,957 F CFA. Elle est plus adoptĂ©e par des petits exploitants, les femmes exploitantes et les hommes exploitants plus ĂągĂ©s (>50 ans) par son caractĂšre de paiement au comptant et rapide. La vente groupĂ©e (26,1%) se pratique par des grands exploitants qui sont membres des groupements coopĂ©ratifs, bĂ©nĂ©ficiant des formations et nĂ©gociant un prix de vente relativement plus intĂ©ressant (entre 450 et 1000 F CFA/Kg). Ce mode est plus observĂ© dans la Commune de Tchaourou, berceau des premiĂšres expĂ©riences de la vente groupĂ©e au BĂ©nin. Par contre, la vente mixte est moins adoptĂ©e (15,9%) par les exploitants. Elle est plus adoptĂ©e par des mĂ©nages de taille relativement Ă©levĂ©e (>9 individus) et permet Ă ses adoptants de rĂ©pondre aux besoins urgents qui leurs sont prĂ©sentĂ©s. La vente groupĂ©e constitue parmi les trois modes celui qui rĂ©munĂšre plus les exploitants du fait de son prix Ă©levĂ© au kilogramme. Elle permet aux exploitants dâavoir accĂšs Ă des formations de renforcement de capacitĂ© et des subventions matĂ©rielles et financiĂšres.
Concern for income security is leading cashew nut farmers in Benin to multiply their marketing methods (individual sales, group sales and mixed sales). The objective of this article is to highlight the socio-economic indicators that guide the choice of cashew nut sales by producers in the municipalities of Djougou, Tchaourou and Glazoue. The Methodological Approach is based on a semi-structured questionnaire addressed to 383 cashew nut producers, selected in a simple random manner in the municipalities of Tchaourou, Djougou and Glazoue. This sample is divided into three (03) observation sub-units: 222 farmers adopting individual sale, 100 farmers adopting group sale and 61 farmers adopting the combination of the two previous modes according to the Dagnelie sampling formula. The analysis was carried out by means of a logistic regression that revealed the factors that discriminate the choice of sales methods. The results of the analyses showed that the sample considered is dominated by men (84,6%) with no education (62,4%), practising agriculture as the main activity (82,2%). Individual selling is practiced by 58% of the sampled farmers. This mode remunerates at a price ranging from 350 to 900 F CFA/Kg, knowing that 1 Euro is equivalent to 655,957 F CFA. It is more adopted by smallholders, women farmers and older male farmers (>50 years old) due to its cash and rapid payment nature. Grouped sales (26,1%) are practiced by large farmers who are members of cooperative groups, benefiting from training and negotiating a relatively more attractive selling price (between 450 and 1000 F CFA/Kg). This mode is more observed in the municipality of Tchaourou, the cradle of the first experiences of group sales in Benin. On the other hand, mixed selling is less adopted (15,9%) by farmers. It is more adopted by relatively large households (>9 individuals) and allows its adopters to meet the urgent needs presented to them. Among the three methods, grouped sales are the one that pays farmers the most because of its high price per kilogram. It allows farmers to have access to capacity building training and material and financial subsidies
Action publique et gouvernance des institutions publiques de recherche en Afrique centrale : cas du Centre national de la recherche scientifique et technologique (CENAREST) au Gabon
En dĂ©pit de quelques efforts gouvernementaux, le pilotage du CENAREST et du secteur de la recherche scientifique au Gabon ne semble guĂšre rĂ©pondre aux attentes, aussi bien des acteurs gouvernementaux quâĂ celles des citoyens gabonais. La rĂ©currence des interpellations des autoritĂ©s, la place accordĂ©e Ă la recherche scientifique et son statut de levier du dĂ©veloppement du pays semblent ne pas sâaccompagner des actes incitatifs et des mesures favorisant lâamorce dâune gestion rassurante et efficiente de ce secteur public et des activitĂ©s de recherche. Le dessein poursuivi par cette recherche doctorale est de produire un modĂšle explicatif permettant de comprendre lâaction publique et les vellĂ©itĂ©s de rĂ©sistance au changement des autoritĂ©s institutionnelles et gouvernementales face au constat des dysfonctionnements dressĂ©s, de maniĂšre rĂ©currente, aussi bien par les partenaires internationaux que par la partie gabonaise. Ce travail de recherche a ainsi permis de prĂ©senter, Ă partir de la construction dâun rĂ©fĂ©rentiel inspirĂ© de Muller, les valeurs, les images, les normes et les algorithmes issus de 16 rĂ©cits de pratique dâacteurs du CENAREST et du secteur de la recherche au Gabon. Cette recherche de type qualitatif sâinscrit dans le domaine de lâanalyse cognitive des politiques publiques, parfois appelĂ©es sociologie politique de lâaction publique. En plus de lâanalyse des politiques sectorielles de Muller et de lâanalyse documentaire, elle bĂ©nĂ©ficie du croisement de lâapproche biographique de Bertaux. Lâanalyse cognitive des donnĂ©es montre aussi, dâune part, comment ce travail a facilitĂ© la comprĂ©hension du rĂŽle, de la place, des contextes dâexĂ©cution et des dispositifs de la recherche scientifique et technologique au Gabon et dans la CommunautĂ© Ă©conomique et monĂ©taire de lâAfrique centrale (CEMAC). Dâautre part, il est juste dâadmettre que le Gabon nâest pas encore une sociĂ©tĂ© moderne ou complexe (Muller, 1985, 2005). La recherche montre parfaitement que lâabsence, aussi bien de processus global de la sectorisation que de la politique sectorielle de la recherche scientifique et technologique, est tributaire du caractĂšre balbutiant et embryonnaire de la sociĂ©tĂ© gabonaise. Le dĂ©ficit prononcĂ© des secteurs, assez bien articulĂ©s et dynamiques, justifie consĂ©quemment la carence des mĂ©diateurs du changement social au Gabon. Mots clĂ©s : Politique publique, recherche scientifique, gouvernance, secteur, acteur.Despite some efforts deployed by the government, the management of the CENAREST and the sector of scientific research in Gabon do not seem to meet expectations of the government actors and Gabonese citizens. Even if authorities often intervened, that emphasis was put on scientific research and that it is known to be a great lever for the country development, it does not seem to be accompanied by incentives acts and measures promoting a reassuring and efficient management of the public sector and research activities. The purpose of this doctoral research is to produce an explanatory model for understanding public action and resistance toward change shown by the institutional and governmental authorities, despite the malfunctions that were observed by international partners as well as the Gabon party. This research has allowed to show â with a framework inspired by Muller â values, images, standards and algorithms present within 16 stories narrating the practices of actors evolving in the CENAREST and the research sector in Gabon. This qualitative research is in the field of cognitive analysis of public policies, sometimes called political sociology of public action. In addition to the analysis of sectoral policies by Muller and the literature review, it benefits from the crossing of the biographical approach elaborated by Bertaux. The cognitive analysis of the data also shows, on one hand, how this work has contributed to the understanding of role, position and execution contexts as well as mechanisms of scientific and technological research in Gabon and the Economic and Monetary Community of Central Africa (CEMAC). On the other hand, it is fair to admit that Gabon is not a modern or complex society yet (Muller, 1985, 2005). Research shows perfectly that the absence, of both overall process of segmentation and the sectoral policy of scientific and technological research, depends on stammering and embryonic character of Gabonese society. The deficit observed in those areas, which are fairly well articulated and dynamic, explains the lack of mediators of social change in Gabon. Keywords: Public policy, scientific research, governance, sector, actor
Airfoil Tip Leakage Aeroacoustics Predictions using a Lattice Boltzmann Based Method
International audienceThe noise produced by rotating systems such as fans and turbo machines is of growing importance in the academic and engineering communities. The prediction and understanding of the physical mechanisms associated with noise generation are required in order to develop innovative solutions able to efficiently reduce radiated acoustics levels. The flow-induced noise generation mechanisms related to rotating devices are various and complex, and one of them is related to the blade tip flow. The tip flow noise, or tip leakage noise, is particularly important for free-tip configurations, for which the tip flow induced by the pressure gradient between the suction and pressure sides can be particularly intense. The experimental investigation of this mechanism is practically challenging. Consequently, a simplified non-rotating representative configuration has been proposed, and has been previously investigated experimentally. In this paper, transient, compressible, and time-explicit Computational Fluid Dynamics/Computational Aero-Acoustics (CFD/CAA) simulations of an airfoil tip leakage flow for this simplified geometry are performed using a Lattice Boltzmann Method (LBM) based approach. The studied configuration is a NACA 5510 airfoil profile at high Reynolds number flow conditions, for which a variable size gap is introduced between the airfoil and one of the end plates, modeling the tip gap encountered in free-tip fans. First, the simulation results are compared with experimental results to validate the numerical approach. Further investigation of the numerical results underlines the connection between the tip vortex structures and noise radiation, including a parametric study on the Angle of Attack (AoA) and the tip gap width
LA RETICENCE AU SPONSORING DES CLUBS DE FOOTBALL PROFESSIONNEL PAR LES ENTREPRISES AU CAMEROUN
Lâobjectif de notre recherche est dâexaminer le pheÌnomeÌne de reÌticence des entreprises face au sponsoring des clubs de football professionnel. Pour atteindre cet objectif, nous avons adopteÌ pour la meÌthodologie qualitative qui a consisteÌ aÌ mener des entretiens aupreÌs des entreprises par secteur dâactiviteÌ et des clubs de football professionnel, par zone geÌographique. ApreÌs cette eÌtape, nous avons analyseÌ et interpreÌteÌ les donneÌes issues des entretiens. Cette deÌmarche nous a permis de comprendre en profondeur la pratique du sponsoring sportif, les veÌritables raisons qui justifient la reÌticence des entreprises face aÌ sponsoriser les clubs de football professionnel dans notre contexte dâeÌtude et leurs attentes vis-aÌ-vis de ces clubs afin de les sponsoriser. Il sâagit ici de lier le reÌel perçu par les acteurs au pheÌnomeÌne aÌ eÌtudier. AÌ lâissue des reÌsultats obtenus, il ressort que la reÌticence des entreprises aÌ sponsoriser les clubs de football professionnel sâexpliquent par plusieurs facteurs lieÌs aux entreprises, aux clubs et aÌ lâenvironnement. Aussi, la theÌorie de lâaction raisonneÌe nous a permis de comprendre en profondeur ledit pheÌnomeÌne et de formuler des recommandations qui vont favoriseront de manieÌre deÌfinitive et efficace le sponsoring de ces clubs par les entreprises
Designs and Implementations in Neural Network-based Video Coding
The past decade has witnessed the huge success of deep learning in well-known
artificial intelligence applications such as face recognition, autonomous
driving, and large language model like ChatGPT. Recently, the application of
deep learning has been extended to a much wider range, with neural
network-based video coding being one of them. Neural network-based video coding
can be performed at two different levels: embedding neural network-based
(NN-based) coding tools into a classical video compression framework or
building the entire compression framework upon neural networks. This paper
elaborates some of the recent exploration efforts of JVET (Joint Video Experts
Team of ITU-T SG 16 WP 3 and ISO/IEC JTC 1/SC29) in the name of neural
network-based video coding (NNVC), falling in the former category.
Specifically, this paper discusses two major NN-based video coding
technologies, i.e. neural network-based intra prediction and neural
network-based in-loop filtering, which have been investigated for several
meeting cycles in JVET and finally adopted into the reference software of NNVC.
Extensive experiments on top of the NNVC have been conducted to evaluate the
effectiveness of the proposed techniques. Compared with VTM-11.0_nnvc, the
proposed NN-based coding tools in NNVC-4.0 could achieve {11.94%, 21.86%,
22.59%}, {9.18%, 19.76%, 20.92%}, and {10.63%, 21.56%, 23.02%} BD-rate
reductions on average for {Y, Cb, Cr} under random-access, low-delay, and
all-intra configurations respectively
Airfoil Tip Leakage Aeroacoustics Predictions using a Lattice Boltzmann Based Method
The noise produced by rotating systems such as fans and turbo machines is of growing importance in the academic and engineering communities. The prediction and understanding of the physical mechanisms associated with noise generation are required in order to develop innovative solutions able to efficiently reduce radiated acoustics levels. The flow-induced noise generation mechanisms related to rotating devices are various and complex, and one of them is related to the blade tip flow. The tip flow noise, or tip leakage noise, is particularly important for free-tip configurations, for which the tip flow induced by the pressure gradient between the suction and pressure sides can be particularly intense. The experimental investigation of this mechanism is practically challenging. Consequently, a simplified non-rotating representative configuration has been proposed, and has been previously investigated experimentally. In this paper, transient, compressible, and time-explicit Computational Fluid Dynamics/Computational Aero-Acoustics (CFD/CAA) simulations of an airfoil tip leakage flow for this simplified geometry are performed using a Lattice Boltzmann Method (LBM) based approach. The studied configuration is a NACA 5510 airfoil profile at high Reynolds number flow conditions, for which a variable size gap is introduced between the airfoil and one of the end plates, modeling the tip gap encountered in free-tip fans. First, the simulation results are compared with experimental results to validate the numerical approach. Further investigation of the numerical results underlines the connection between the tip vortex structures and noise radiation, including a parametric study on the Angle of Attack (AoA) and the tip gap width
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