Laboratoire Of Mathematiques Appliquees

Saint-Brieuc, France

Laboratoire Of Mathematiques Appliquees

Saint-Brieuc, France
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Abid W.,University of Carthage | Yafia R.,University Ibn Zohr | Aziz-Alaoui M.A.,Laboratoire Of Mathematiques Appliquees | Bouhafa H.,University of Carthage | Abichou A.,University of Carthage
Journal of Applied Nonlinear Dynamics | Year: 2016

This paper is devoted to the study of a three species ecosystem model consisting of a prey, a predator and a top predator. This model is given by a reaction diffusion system defined on a circular spatial domain and incorporates the Holling type II and a modified Leslie-Gower functional response. The aim of this paper is to investigate theoretically and numerically the asymptotic behavior of the interior equilibrium of the model. The conditions of boundedness, existence of a positively invariant and attracting set are proved. Sufficient conditions of local/global stability of the positive steady state are established. In the end, we present a numerical evidence of time evolution of the pattern formation. © 2016. L&H Scientific Publishing, LLC.

Abid W.,University of Carthage | Yafia R.,University Ibn Zohr | Aziz-Alaoui M.A.,Laboratoire Of Mathematiques Appliquees | Bouhafa H.,University of Carthage | Abichou A.,University of Carthage
Discontinuity, Nonlinearity, and Complexity | Year: 2016

In this paper, a finite difference method for a non-linear reaction diffusion equation defined on a circular domain is presented. A simple second-order finite difference treatment of polar coordinate singularity for Laplacian operator, the centered difference approximations, the treatments for Neumann boundary problems are used to discretize this equation. By using this method, numerical solutions can be computed. In the end, we give two applications of reaction diffusion predator-prey models with modified Leslie-Gower and Holling type II functional responses. ©2016 L&H Scientific Publishing.

Causse M.,French National Institute for Agricultural Research | Friguet C.,Laboratoire Of Mathematiques Appliquees | Coiret C.,Laboratoire Of Mathematiques Appliquees | LePicier M.,Laboratoire Of Mathematiques Appliquees | And 6 more authors.
Journal of Food Science | Year: 2010

Abstract: Although tomato flavor has not been a major goal for breeders, nowadays it becomes important as it is a subject of consumer complaint. A better knowledge of tomato consumer preferences, at the European level, should provide the basis for improvement of fruit quality and for market segmentation. In the framework of a large European project, 806 consumers from 3 countries, The Netherlands, France, and Italy, were presented with a set of 16 varieties representing the diversity of fresh tomato offer in order to evaluate their preferences. In parallel, sensory profiles were constructed by expert panels in each country. Preference maps were then constructed in each country revealing the structure of consumer preferences and allowing identification of the most important characteristics. Then a global analysis revealed that preferences were quite homogeneous across countries. This study identified the overall flavor and firmness as the most important traits for improving tomato fruit quality. It showed that consumer preferences from different European countries, with different cultures and food practices, are segmented following similar patterns when projected onto a common referential plan. Moreover, the results clearly showed that diversification of taste and texture is required to satisfy all consumers' expectations as some consumers preferred firm tomatoes, while others preferred melting ones and were more or less demanding in terms of sweetness and flavor intensity. Detailed comparisons also showed the importance of the fruit appearance in consumer preference.Practical Application: The consumer preferences for fresh market tomato were studied in 3 European countries. The main descriptors for further breeding for consumer satisfaction were identified. Four clusters of consumers were identified in the overall analysis, the 3 countries contributing the same way to each cluster. The impact of appearance in the preferences was also underlined. Journal compilation © 2010 Institute of Food Technologists® No claim to original government works.

Yafia R.,University Ibn Zohr | Aziz-Alaoui M.A.,Laboratoire Of Mathematiques Appliquees | Tridane A.,United Arab Emirates University | Rihan F.,United Arab Emirates University
MATEC Web of Conferences | Year: 2014

In this paper, we consider a model describing the dynamics of Hematopoietic Stem Cells (HSC) disease with chemotherapy. The model is given by a system of three ordinary differential equations with discrete delay. Its dynamics are studied in term of local stability of the possible steady states for the case without drug intervention term. We prove the existence of periodic oscillations for each case when the delay passes trough a critical values. In the end, we illustrate our results by some numerical simulations. © 2014 published by EDP Sciences.

D'Olivo P.,Polytechnic of Milan | Del Curto B.,Polytechnic of Milan | Faucheu J.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Lafon D.,Ecole des Mines d'Ales | And 3 more authors.
Proceedings of the International Conference on Engineering Design, ICED | Year: 2013

The analysis of users' experience is indispensable in order to catch the subjectivity. For this reason the industrial designer needs to take into account these new qualitative properties, and translate them in a concrete way during the creative process. Firstly the sensory information acquired need to be coached by the material experience. The user is able to construct his relation with the product primarily interfacing himself with the skin of the object by touch and sight, and after that explore its functionality. The work aims to improve the development of emotional and feeling investigation by the use of an holistic approach that take into account all the product's aspects. To realise this investigation has been chosen to apply the technique offered by Sensory Metrology discipline and two methods derived from the Classical Sensory Evaluation. In this paper the test experiences done in order to read users' subjectivity have been described. The different proofs have been structured in three different moments. Results have shown the possibility to use the sensorial sphere as a constructive matter to achieve user's affection to the products always from an holistic point of view. © 2013 The Design Society.

Vanaret C.,Laboratoire Of Mathematiques Appliquees | Vanaret C.,CNRS Toulouse Institute in Information Technology | Gotteland J.-B.,Laboratoire Of Mathematiques Appliquees | Gotteland J.-B.,CNRS Toulouse Institute in Information Technology | And 3 more authors.
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

Evolutionary Algorithms (EA) usually carry out an efficient exploration of the search-space, but get often trapped in local minima and do not prove the optimality of the solution. Interval-based techniques, on the other hand, yield a numerical proof of optimality of the solution. However, they may fail to converge within a reasonable time due to their exponential complexity and their inability to quickly compute a good approximation of the global minimum. The contribution of this paper is a hybrid algorithm called Charibde in which a particular EA, Differential Evolution, cooperates with a branch and bound algorithm endowed with interval propagation techniques. It prevents premature convergence toward local optima and is highly competitive with both deterministic and stochastic existing approaches. We demonstrate its efficiency on a benchmark of highly multimodal problems, for which we provide previously unknown global minima and certification of optimality. © Springer International Publishing Switzerland 2014.

Marechal L.,Laboratoire Of Mathematiques Appliquees | Perez J.,Laboratoire Of Mathematiques Appliquees
Monthly Notices of the Royal Astronomical Society | Year: 2010

This paper is devoted to radial orbit instability in the context of self-gravitating dynamical systems. We present this instability in the new frame of dissipation-induced instability theory. This allows us to obtain a rather simple proof based on energetics arguments and to clarify the associated physical mechanism. © 2010 The Authors. Journal compilation © 2010 RAS.

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