Réné Tchinda

Estimation of mean wind energy available in far north Cameroon

Abstract From wind speed data recorded over 5 years (1991–1995), as observed in the main meteorological station, a synoptical station of the observation network of the National Meteorology Service located in the far north of Cameroon, an estimation of the wind energy available has been prepared. For this use, the wind speed frequencies during the period are considered. Possible applications of this energy for this station are discussed.

Wind energy in Adamaoua and North Cameroon provinces

Abstract From the wind speed data recorded over 9 (1990–1998) and 10 (1990–1999) years, as observed in the main meteorological stations, called synoptical stations, of the observation network of the National Meteorology Department, located in the Adamaoua and Northern Cameroon provinces, an estimation of the wind energy available has been made for each station. For this use, the wind speed frequencies in the period are considered. Daily, monthly and annual mean wind speeds and wind energy available were determined. The possible applications of this energy for each station are discussed.

Study of the C.P.C. collector thermal behaviour

In this paper, analyses of the heat exchanges in the C.P.C. collector, including axial heat transfer in the receiver, are presented. An explicit expression of the temperature of the heat transfer fluid as a function of the space co-ordinate in the flow direction and the time dependent solar intensity is developed. Then, the effect of various parameters, such as the inlet heat transfer fluid temperature and the mass flow rate, on the dynamic behaviour of the collector is studied. The predicted results were also compared with experiments.

Heat and mass transfer processes in a solar still with an indirect evaporator-condenser

Abstract The thermal performances of a solar still of a new type are analysed. The still is made of a flat plate heater coupled with an evaporator–condenser recently studied by the same authors (Njomo D, Tchinda R, Kaptouom E. J. Solar Energy Engng., Trans. ASME 1996;118(3):177). The theoretical solar still productivity is in reasonably good agreement with the experimental distillation yields, reported in the literature for heat exchange fluxes less than 1 kW/m 2 usually encountered in solar stills.

Automatic recognition of human parasite cysts on microscopic stools images using principal component analysis and Probabilistic Neural Network

Parasites live in a host and get its food from or at the expensive of that host. Cysts represent a form of resistance and spread of parasites. The manual diagnosis of microscopic stools images is time-consuming and depends on the human expert. In this paper, we propose an automatic recognition system that can be used to identify various intestinal parasite cysts from their microscopic digital images. We employ image pixel feature to train the probabilistic neural networks (PNN). Probabilistic neural networks are suitable for classification problems. The main novelty is the use of features vectors extracted directly from the image pixel. For this goal, microscopic images are previously segmented to separate the parasite image from the background. The extracted parasite is then resized to 12x12 image features vector. For dimensionality reduction, the principal component analysis basis projection has been used. 12x12 extracted features were orthogonalized into two principal components variables that consist the input vector of the PNN. The PNN is trained using 540 microscopic images of the parasite. The proposed approach was tested successfully on 540 samples of protozoan cysts obtained from 9 kinds of intestinal parasites. - See more at: http://thesai.org/Publications/ViewPaper?Volume=4&Issue=9&Code=ijarai&SerialNo=6#sthash.S5fRMF9g.dpuf

ECOP Criterion for Irreversible Three-Heat-Source Absorption Refrigerators

© 2012 Ngouateu Wouagfack and Tchinda, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ECOP Criterion for Irreversible Three-Heat-Source Absorption Refrigerators

Edge detection of intestinal parasites in stool microscopic images using multi-scale wavelet transform

Biomedical image processing is experiencing a significant progress with many applications. However, automatic recognition of microscopic pathogens from their images remains a challenge that will allow clinical laboratories to increase both the speed of tests and the reliability of diagnoses. We present an algorithm for edge detection of parasites in microscopic images of stools, using the multi-scale wavelet transform. This method is an evolution of the Canny–Mallat detector which gives the possibility to vary the frequency of the analysis in order to find the outlines of the most significant edges. The various contours obtained are chained across the scales from the coarsest to the finest. Using this algorithm, we were able to correctly represent the contours of the features of parasites found in microscopic images. The results obtained were compared with those produced by classical edge detectors on the same images. It comes out from both subjective and objective quantitative performances evaluation that our detector, better than all others, can clearly mark the outlines of the structures of the pathogen on an image of stools.

ANALYSIS OF INTEREST POINTS OF CURVELET COEFFICIENTS CONTRIBUTIONS OF MICROSCOPIC IMAGES AND IMPROVEMENT OF EDGES

This paper focuses on improved edge model based on Curvelet coefficients analysis. Curvelet transform is a powerful tool for multiresolution representation of object with anisotropic edge. Curvelet coefficients contributions have been analyzed using Scale Invariant Feature Transform (SIFT), commonly used to study local structure in images. The permutation of Curvelet coefficients from original image and edges image obtained from gradient operator is used to improve original edges. Experimental results show that this method brings out details on edges when the decomposition scale increases.