EASEA: specification and execution of evolutionary algorithms on GPGPU

EASEA is a framework designed to help non-expert programmers to optimize their problems by evolutionary computation. It allows to generate code targeted for standard CPU architectures, GPGPU-equipped machines as well as distributed memory clusters. In this paper, EASEA is presented by its underlying algorithms and by some example problems. Achievable speedups are also shown onto different NVIDIA GPGPUs cards for different optimization algorithm families.     

Contribution to the prediction of performances of the hough transform

Exact predictions of the performances of the Hough detection of straight lines in two-dimensional images are presented for rectangular and circular retinas, in Cartesian and normal parameterization, in the case of noisy signals. Detection of circles, under the same assumptions, is discussed. The limits of adaptive quantization to reduce intrinsic noise are presented, and it is shown that a signal processing approach is especially convenient to measure the performances of a detector based on the Hough transform.     

Indexing and querying segmented web pages: the BlockWeb Model

We present in this paper a model for indexing and querying web pages, based on the hierarchical decomposition of pages into blocks. Splitting up a page into blocks has several advantages in terms of page design, indexing and querying such as (i) blocks of a page most similar to a query may be returned instead of the page as a whole (ii) the importance of a block can be taken into account, as well as (iii) the permeability of the blocks to neighbor blocks: a block b is said to be permeable to a block b?? in the same page if b?? content (text, image, etc.) can be (partially) inherited by b upon indexing. An engine implementing this model is described including: the transformation of web pages into blocks hierarchies, the definition of a dedicated language to express indexing rules and the storage of indexed blocks into an XML repository. The model is assessed on a dataset of electronic news, and a dataset drawn from web pages of the ImagEval campaign where it improves by 16% the mean average precision of the baseline.     

On the corrosion resistance of the submerged arc welded titanium in concentrated hydrochloric acid 8 N

The corrosion behaviour of the submerged arc welded T-35 in concentrated 8 N HCl has been investigated. The weld metal is characterized by a martensite type structure, a hardness superior by 60 HV and an oxygen content about two and a half times higher than the base metal. In order to underline the part played by oxygen and structural transformations intervening during the welding operation, an analysis of the anodic current-potential curves by a reaction model involving four determining steps has been carried out. It has been shown that the two reaction rates which determine the passivation and the passivity of the metal depend on the oxygen content as well as the metallurgical structure. In the active dissolution range, whereas one of the two determining rates depends on the oxygen content, the other one is controlled by the metallurgical structure of the metal.     

Influence of H2/NH3 mixtures on the composition of SiCNYO and SiCNAl(O) nanopowders

We performed pyrolysis of SiCNAlH and SiCNYOH nanopowder precursors under a reactive atmosphere (Ar/NH₃/H₂) with various compositions of ammonia (NH₃) and dihydrogen (H₂) to diminish C content, which is deleterious for thermal stability and sintering of the powders. This paper continues a previous work on the fabrication of an Si₃N₄/SiC composite without free C by studying the effect of H₂ on the C/N atomic ratio of the powder. We studied the influence of the nature of the gaseous mixture (Ar/NH₃/H₂) on the powder composition. Elemental analysis showed that the introduction of H₂ in the pyrolysis atmosphere limited the decomposition of NH₃ and allowed for control of the C/N ratio. This behaviour can be explained by the structural evolution observed by ²⁹Si NMR spectrometry but also by Fourier transform infrared and Raman spectroscopy. An Si₃N₄/SiC composite, with traces of free C, was obtained after post-pyrolysis heat treatment of the powders synthesized with 10 wt.% of H₂ and 25 wt.% NH₃.     

Depth and depth–color coding using shape-adaptive wavelets

We present a novel depth and depth–color codec aimed at free-viewpoint 3D-TV. The proposed codec uses a shape-adaptive wavelet transform and an explicit encoding of the locations of major depth edges. Unlike the standard wavelet transform, the shape-adaptive transform generates small wavelet coefficients along depth edges, which greatly reduces the bits required to represent the data. The wavelet transform is implemented by shape-adaptive lifting, which enables fast computations and perfect reconstruction. We derive a simple extension of typical boundary extrapolation methods for lifting schemes to obtain as many vanishing moments near boundaries as away from them. We also develop a novel rate-constrained edge detection algorithm, which integrates the idea of significance bitplanes into the Canny edge detector. Together with a simple chain code, it provides an efficient way to extract and encode edges. Experimental results on synthetic and real data confirm the effectiveness of the proposed codec, with PSNR gains of more than 5 dB for depth images and significantly better visual quality for synthesized novel view images.     

Effect of 15-deoxyspergualine on antigen-specific lymphocyte activation measured by CD69 expression

The sarcosine oxidase from Bacillus sp. NS-129 has been crystallized by vapor diffusion using ammonium sulfate as precipitant. The tetragonal crystals have P4(1)2(1)2 (or P4(3)2(1)2) symmetry with a = b = 177.0 and c = 72.6 A. The crystals probably contain two sarcosine oxidase molecules per asymmetric unit and diffract to at least 2.7 A resolution.     

Neurochemical and electrophysiological evidence for the existence of a functional gamma-hydroxybutyrate system in NCB-20 neurons

Clonal neurohybridoma NCB-20 cells express a valproate-insensitive succinic semialdehyde reductase activity that transforms succinic semialdehyde into gamma-hydroxybutyrate. This activity (1.14+/-0.16 nmol/min/mg protein) was similar to the lowest activity existing in adult rat brain. [3H]gamma-Hydroxybutyrate labels a homogeneous population of sites on NCB-20 cell membranes (Kd=250+/-44.4nM, Bmax=180+/-16.2fmol/mg protein) that apparently represents specific gamma-hydroxybutyrate binding sites characterized previously on brain cell membranes. Finally, an Na+-dependent uptake of [3H]gamma-hydroxybutyrate was expressed in NCB-20 cells with a Km of 35+21.1 microM and a Vmax of 80+/-14.2 pmol/min/mg protein. A three-day treatment with 1 mM dibutyryl-cyclic-AMP induced a three-fold increase in the cellular succinic semialdehyde reductase activity. In parallel, a K+-evoked release of [3H]gamma-hydroxybutyrate occurred. This release was Ca2+ dependent and was not present in undifferentiated cells. Cyclic-AMP treatment induced a decrease of [3H]gamma-hydroxybutyrate binding sites, which could be due to spontaneous gamma-hydroxybutyrate release. Patch-clamp experiments carried out on differentiated NCB-20 cells revealed the presence of Ca2+ conductances which were partially inhibited by 50 microM gamma-hydroxybutyrate. This gamma-hydroxybutyrate-induced effect was blocked by the gamma-hydroxybutyrate receptor antagonist NCS-382, but not by the GABA(B) antagonist CGP-55845. These results demonstrate the presence of an active gamma-hydroxybutyratergic system in NCB-20 cells which possesses the ability to release gamma-hydroxybutyrate. These cells express specific gamma-hydroxybutyrate receptors which modulate Ca2+ currents independently of GABA(B) receptors.