Amroune A.,ila University |
Davvaz B.,University of Yazd
Iranian Journal of Fuzzy Systems | Year: 2011
The starting point of this paper is given by Priestley's papers, where a theory of representation of distributive lattices is presented. The purpose of this paper is to develop a representation theory of fuzzy distributive lattices in the finite case. In this way, some results of Priestley's papers are extended. In the main theorem, we show that the category of finite fuzzy Priestley spaces is equivalent to the dual of the category of finite fuzzy distributive lattices. Several examples are also presented.
Mezahi F.Z.,University of Mentouri Constantine |
Mezahi F.Z.,ila University |
Oudadesse H.,University of Rennes 1 |
Harabi A.,University of Mentouri Constantine |
Le Gal Y.,University of Rennes 1
International Journal of Applied Ceramic Technology | Year: 2012
In this study, the ability to form bone-like apatite on surface of both pure natural hydroxapatite (N-HA) and natural hydroxyapatite containing 5 wt% of ZrO 2 or TiO 2 or Al 2O 3, sintered at 1300°C for 2 h and soaked in the simulated body fluid for different times, was studied. It has been found that the presence of β-tricalcium phosphate in N-HA + 5 wt% ZrO 2 or TiO 2 has promoted the precipitation of bone-like apatite in the Zr or Ti poorest regions. By contrast, the presence of 5 wt% of Al 2O 3 did not induce any apatite precipitation on N-HA sample surfaces. © 2012 American Ceramic Society.
Mezahi F.-Z.,University of Mentouri Constantine |
Mezahi F.-Z.,ila University |
Girot A.L.-.,CNRS Chemistry Institute of Rennes |
Oudadesse H.,CNRS Chemistry Institute of Rennes |
Harabi A.,University of Mentouri Constantine
Journal of Non-Crystalline Solids | Year: 2013
A new composition of bioactive glass, in the quaternary system SiO 2-CaO-Na2O-P2O5, was synthesized using melting and sol-gel routes. The prepared glass, 52S4: (wt.%) 52% SiO 2-30% CaO-14% Na2O-4% P2O5, was soaked in Simulated Body Fluid (SBF) in order to evaluate the kinetic reactivity of this glass versus the synthesis mode. The obtained results have shown that 52S4 is a bioactive glass if it is prepared either by melting or sol-gel methods. The bone-like apatite was formed at the glass surface prepared by sol-gel route after 2 h. However, the formation of this apatite was delayed to 1 day when the glass was prepared by melting method. In addition, this apatite was crystallized, after 30 days soaking in SBF, only if the glass is prepared by melting route. The glass prepared by sol-gel method was more resorbable and leads to silica gel formation up on amorphous apatite layers at any time. So, this silica gel inhibited the crystallization of amorphous apatite. © 2012 Elsevier B.V.
Chemachema M.,ila University |
Belarbi K.,University of Mentouri Constantine
International Journal of Modelling, Identification and Control | Year: 2010
In this paper, a neural network (NN) direct adaptive control algorithm is presented for a class of uncertain SISO non-linear systems. In the proposed approach there is no sign constraint on the system control gain and/or on its derivative as done in the literature. The NN approximates an ideal controller in feedback linearisation form based on an estimate of the control error signal used in the adaptive laws derivation. An estimated value of the control error is provided by a fuzzy inference system composed of a set of rules determined heuristically from information related to the history of the output tracking error. Lyapunov direct method is then used to prove the global exponential boundedness of all the signals involved in the closed loop and hence the stability of the system. Simulation results demonstrate the effectiveness of the proposed approach. Copyright © 2010 Inderscience Enterprises Ltd.
Terki N.,University Mohamed Khider of Biskra |
Saigaa D.,ila University |
Cheriet L.,University Mohamed Khider of Biskra |
Doghmane N.,Annaba University
Journal of Signal Processing Systems | Year: 2013
In this paper, we introduce an algorithm for motion estimation. It combines complex wavelet decomposition and a fast motion estimation method based on affine model. The principle of wavelet transform is to decompose hierarchically the input image into a series of successively lower resolution reference images and detail images which contain the information needed to be reconstructed back to the next higher resolution level. The motion estimation determines the velocity field between two successive images. This phase can be extracted from this measure descriptive information of the sequence. Motion Estimation (ME) is an important part of any video compression system, since it can achieve significant compression by exploiting the temporal redundancy existing in a video sequence. This paper described a method from calculating the optical flow of an image sequence based on complex wavelet transform. It consists to project the optical flow vectors on a basis of complex-valued wavelets. Thus, we add an additional assumption on the shape of the velocity field that we want to find, which is the affinity of the optical flow. The two-dimensional affine motion model is used to formulate the optical flow problem by coarse resolution simultaneously coarse-and-fine, beside the traditional approach by coarse-to-fine, to avoid the error propagation during the decomposition of coarse level to fine level. This method opens the way for a quick and low-cost computing optical flow. © 2012 Springer Science+Business Media New York.