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Search Results: 1 - 10 of 219 matches for " Yahia Lebbah "
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On Testing Constraint Programs
Nadjib Lazaar,Arnaud Gotlieb,Lebbah Yahia
Computer Science , 2010,
Abstract: The success of several constraint-based modeling languages such as OPL, ZINC, or COMET, appeals for better software engineering practices, particularly in the testing phase. This paper introduces a testing framework enabling automated test case generation for constraint programming. We propose a general framework of constraint program development which supposes that a first declarative and simple constraint model is available from the problem specifications analysis. Then, this model is refined using classical techniques such as constraint reformulation, surrogate and global constraint addition, or symmetry-breaking to form an improved constraint model that must be thoroughly tested before being used to address real-sized problems. We think that most of the faults are introduced in this refinement step and propose a process which takes the first declarative model as an oracle for detecting non-conformities. We derive practical test purposes from this process to generate automatically test data that exhibit non-conformities. We implemented this approach in a new tool called CPTEST that was used to automatically detect non-conformities on two classical benchmark programs, namely the Golomb rulers and the car-sequencing problem.
Revisiting the upper bounding process in a safe Branch and Bound algorithm
Alexandre Goldsztejn,Yahia Lebbah,Claude Michel,Michel Rueher
Mathematics , 2008,
Abstract: Finding feasible points for which the proof succeeds is a critical issue in safe Branch and Bound algorithms which handle continuous problems. In this paper, we introduce a new strategy to compute very accurate approximations of feasible points. This strategy takes advantage of the Newton method for under-constrained systems of equations and inequalities. More precisely, it exploits the optimal solution of a linear relaxation of the problem to compute efficiently a promising upper bound. First experiments on the Coconuts benchmarks demonstrate that this approach is very effective.
A global Constraint for mining Sequential Patterns with GAP constraint
Amina Kemmar,Samir Loudni,Yahia Lebbah,Patrice Boizumault,Thierry Charnois
Computer Science , 2015,
Abstract: Sequential pattern mining (SPM) under gap constraint is a challenging task. Many efficient specialized methods have been developed but they are all suffering from a lack of genericity. The Constraint Programming (CP) approaches are not so effective because of the size of their encodings. In[7], we have proposed the global constraint Prefix-Projection for SPM which remedies to this drawback. However, this global constraint cannot be directly extended to support gap constraint. In this paper, we propose the global constraint GAP-SEQ enabling to handle SPM with or without gap constraint. GAP-SEQ relies on the principle of right pattern extensions. Experiments show that our approach clearly outperforms both CP approaches and the state-of-the-art cSpade method on large datasets.
Prefix-Projection Global Constraint for Sequential Pattern Mining
Amina Kemmar,Samir Loudni,Yahia Lebbah,Patrice Boizumault,Thierry Charnois
Computer Science , 2015,
Abstract: Sequential pattern mining under constraints is a challenging data mining task. Many efficient ad hoc methods have been developed for mining sequential patterns, but they are all suffering from a lack of genericity. Recent works have investigated Constraint Programming (CP) methods, but they are not still effective because of their encoding. In this paper, we propose a global constraint based on the projected databases principle which remedies to this drawback. Experiments show that our approach clearly outperforms CP approaches and competes well with ad hoc methods on large datasets.
Assessment of Aquifer Vulnerability Based on GIS and ARCGIS Methods: A Case Study of the Sana’a Basin (Yemen)  [PDF]
Yahia Alwathaf, Bouabid El Mansouri
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.312094
Abstract: Groundwater is the main source of water in arid and semi-arid regions. Therefore, pollution of groundwater is a major issue because aquifers and the contained groundwater are inherently susceptible to contamination from wastewater and agricultural activities. Aquifer vulnerability has been assessed in the Sana’a basin using the DRASTIC method, based on a Geographic Information System (GIS). The DRASTIC model uses seven environmental parameters (Depth to water, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and hydraulic Conductivity) to characterize the hydrogeological setting and evaluate aquifer vulnerability. A regional scale aquifer vulnerability map of the basin was prepared using overlay analysis with the aid of GIS. A DRASTIC vulnerability map, verified by data of nitrate in groundwater, shows that the defined areas are compatible with land-use data. It is concluded that 6.4% of the basin area is highly vulnerable and urgent pollution-preventions measures should be taken for every kind of relevant activity within the whole basin.
Statistical Studies of the Physicochemical Analytic Results of a Series of Synthetic Calcium Hydroxyapatite Containing Carbonate and Sodium  [PDF]
Faouzia Rockh B. Hadj Yahia, Ismail Khattech
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.55042
Abstract: The objective of this study is to present a simple method of statistical calculation that allowed us to determine the relationship between the different data obtained from the characterization of the synthetic carbonated apatites containing sodium, in order to find the fundamental substitution mechanism(s) for incorporation of Na+ and CO32- and to establish the general formula. For that, a series of hydroxyapatites containing carbonate and sodium (Na-CO3HAps) has been obtained by the precipitation method. All the compounds were characterized by infrared spectra (IR), powder X-ray diffraction (PXRD) and elemental analysis. The statistical treatment of the experiment result allows us to determine the relationship between one variable and the change in the other and to found the fundamental substitution mechanism(s) for incorporation of Na+ and CO32- . Analysis of variance (ANOVA) allows us to test the models proposed.
Synthesis and Analysis of Some Bis-Heterocyclic Compounds Containing Sulphur
Yahia Nasser Mabkhoot
Molecules , 2009, DOI: 10.3390/molecules14051904
Abstract: A facile and convenient synthesis of a series of bisheterocycles 7a,b 10, 12 and 13a,b containing a thieno[2,3-b]thiophene base unit via the versatile, hitherto unreported 3-[3,4-dimethyl-5-(3-nitrilopropanoyl)thieno[2,3-b]thiophen-2-yl]-3-oxopropanenitrile (4) is described.
Synthesis and Chemical Characterisation of New Bis-Thieno [2,3-b]thiophene Derivatives
Yahia Nasser Mabkhoot
Molecules , 2010, DOI: 10.3390/molecules15053329
Abstract: Using 3-methyl-4-phenylthieno[2,3-b]thiophene-2,5-dicarbohydrazide as synthon a series of new bis-heterocycles incorporating the thieno[2,3-b]thiophene nucleus was prepared and characterized.
Nonlinear wavelet regression function estimator for censored dependent data
D Yahia, F Benatia
Afrika Statistika , 2012,
Abstract: Let (Y;C;X) be a vector of random variables where Y; C and X are, respectively, the interest variable, a right censoring and a covariable (predictor). In this paper, we introduce a new nonlinear wavelet-based estimator of the regression function in the right censorship model. An asymptotic expression for the mean integrated squared error of the estimator is obtained to both continuous and discontinuous curves. It is assumed that the lifetime observations form a stationary ..mixing sequence. Resume. Soit (Y;C;X) un vecteur de variables aleatoires ou Y;C et X sont, respectivement, la variable d'inter^et, une censure a droite et une covariable (predicteur). Dans cet article, nous introduisons un nouveau estimateur de la fonction de regression base sur les ondelettes non lineaire dans le modele de la censure a droite. Une expression asymptotique de l'erreur quadratique moyenne integree de l'estimateur est obtenue pour les deux courbes continues et discontinues. On suppose que les observations de la duree de vie forment une suite α-melangeante.
Influence of the Urbanization on the Risk of Flooding by Runoff
Benabdesselam Tamara,Hammar Yahia
Online Journal of Earth Sciences , 2012,
Abstract: The urbanization is a recent enough phenomenon so much in the industrialized countries that in the developing countries. One of the most visible consequences of the urbanization is the impermeabilisation of soils, which influences considerably on the features of the hydrological response of the watershed and was often bets forward to explain the urban flooding by runoff. In this study, we used like model of simulation, the non-distributed one of linear reservoir, to determine the influence of the urbanization on hydrological response of the watershed. The obtained results show that in case of the urbanization, the lag time of the considered watershed is a lot shorter and also the peak flow increases considerably.
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