Conservatoire national des arts et métiers

About: Conservatoire national des arts et métiers is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Context (language use). The organization has 3573 authors who have published 7127 publications receiving 141430 citations. The organization is also known as: CNAM & Conservatoire des arts et métiers.

Semantic interactive image retrieval combining visual and conceptual content description

Abstract: We address the challenge of semantic gap reduction for image retrieval through an improved support vector machines (SVM)-based active relevance feedback framework, together with a hybrid visual and conceptual content representation and retrieval. We introduce a new feature vector based on projecting the keywords associated to an image on a set of "key concepts" with the help of an external lexical database. We then put forward two improvements of SVM-based relevance feedback method. First, to optimize the transfer of information between the user and the system, we introduce a new active learning selection criterion that minimizes redundancy between the candidate images shown to the user. Second, as most image classes span a wide range of scales in the description space, we argue that the insensitivity of the SVM to the scale of the data is desirable in this context and we show how to obtain it by using specific kernel functions. Experimental evaluations show that the joint use of the new concept-based feature vector and the visual features with our relevance feedback scheme can significantly improve the quality of the results.

Highly active poly(3-hexylthiophene) nanostructures for photocatalysis under solar light

Abstract: Conjugated polymer nanostructures have recently emerged as a new class of very active photocatalysts under solar light. Poly(3-hexylthiophene) (P3HT) is one of the commonly used conjugated polymers for photovoltaics applications. P3HT nanostructures synthesized in soft templates provided by hexagonal mesophases show high photocatalytic activity for degradation of pollutants under both UV and visible light. These photocatalysts are very stable even after repeated cycling. Addition of scavengers and mechanistic studies show that O2 − is the main radical responsible for degradation of phenol taken as a model pollutant. P3HT nanostructures can be easily deposited on flat supports such as quartz for photocatalytic applications avoiding a separation step by centrifugation. Most interestingly, the photocatalytic activity of these P3HT nanostructures is highly enhanced when they are supported on a solid surface opening new perspectives in photocatalytic reactors and self-cleaning surfaces.

Non-Darcian forced convection analysis in an annulus partially filled with a porous material

Abstract: Numerical solutions are presented for fully developed forced convection in concentric annuli partially filled with a porous medium The porous medium is attached at the inner cylinder, which is maintained at uniform heat flux or at uniform wall temperature while the outer cylinder is adiabatic The Brinkman-Forchheimer-extended Darcy model was used to model the flow inside the porous medium The dependence of the fluid flow and heat transfer on several parameters of the problem is thoroughly documented The inertia coefficient at which the inertial effects reduce the flow rate by 5% is determined as a function of the Darcy number for various thicknesses of the porous substrate It is also shown that a critical thickness at which the value of the Nusselt number reaches a minimum does not exist if the effective thermal conductivity of the fluid-saturated porous medium is much higher than the fluid conductivity