Résumé : Le présent rapport est constitué de six parties. Dans la 1ère partie, nous donnons quelques généralités introductives sur la mangrove, et plus spécifiquement sur la mangrove de Nouvelle-Calédonie, ainsi que sur notre site d’étude. La 2nde partie est consacrée à l’évaluation de la biodiversité végétale ainsi qu’à la caractérisation de la structure de la formation de mangrove étudiée. La 3ème partie est consacrée à l’étude de la géochimie des sédiments de mangrove, cette section est divisée en 2 sous-parties, l’une concernant les formes azotées, l’autre concernant le carbone et les métaux lourds. La 4ème partie concerne l’étude des assemblages meïobenthiques, qui réagissent fortement à des perturbations de type organique. La 5ème partie est dédiée à la crevetticulture et à l’inventaire de solutions de gestion des effluents. Cette partie comprend quatre sections. La 1ère section a pour vocation de présenter les caractéristiques de la filière crevettière de Nouvelle-Calédonie. La 2nde section donne les caractéristiques des effluents crevettiers. La 3ème section est le résultat des recherches bibliographiques sur les moyens de gestion des effluents. Enfin la 4ème section est une discussion de faisabilité sur ces moyens de gestion. La 6ème partie de ce rapport, intègre les aspects sociologiques des connaissances et des perceptions des éleveurs à propos de la mangrove et des effluents. Dans la synthèse générale de ce rapport, nous proposerons dans un premier temps des conclusions à propos de la géochimie des sédiments des sédiments de mangrove et des différents facteurs forçants. Dans un second temps, nous serons amenés à prendre en compte les résultats de l’étude sociologique dans le but de mener une réflexion sur les différents moyens de gestion des effluents applicables en Nouvelle-Calédonie.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/00198/30917/29288.pdf
http://archimer.ifremer.fr/doc/00198/30917/

Éditeur(s) : HAL CCSD
Résumé : The convex feasibility problem (CFP) is to find a member of the intersection of finitely many closed convex sets in Euclidean space. When the intersection is empty, one can minimize a proximity function to obtain an approximate solution to the problem. The split feasibility problem (SFP) and the split equality problem (SEP) are generalizations of the CFP. The approximate SFP (ASFP) and approximate SEP (ASEP) involve finding only approximate solutions to the SFP and SEP, respectively. We present here the SSEA, a simultaneous iterative algorithm for solving the ASEP. When this algorithm is applied to the ASFP it resembles closely, but is not equivalent to, the CQ algorithm. The SSEA involves orthogonal projection onto the given closed convex sets. The relaxed SSEA (RSSEA) is an easily implementable variant of the SSEA that uses orthogonal projection onto half-spaces at each step to solve the SEP. The perturbed version of the SSEA (PSSEA) is similar to the RSSEA, but uses orthogonal projection onto a sequence of epi-convergent closed convex sets.
https://hal.univ-antilles.fr/hal-00776640

Droits : info:eu-repo/semantics/OpenAccess
hal-00776640
https://hal.univ-antilles.fr/hal-00776640
https://hal.univ-antilles.fr/hal-00776640/document
https://hal.univ-antilles.fr/hal-00776640/file/CBAM10.pdf

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This article is devoted to the presentation of a multilevel method using finite differences that is well adapted for solving Stokes and Navier-Stokes problems in primitive variables. We use Uzawa type algorithms to solve the saddle point problems arising from spatial discretization by staggered grids and a semi-explicit temporal scheme. By means of a new change of basis operator, the two-dimensional velocity and pressure fields of an M.A.C mesh are gathered in a hierarchical order, into several grids preserving the M.A.C property on each of them. These new hierarchical unknowns, called Staggered Incremental Unknowns (SIU), allow us to develop techniques which reduce the cost of the resolution of either Stokes or generalized Stokes problems. An experimental estimation of the condition number of the inner matrix is given, and justifies the preconditioning effect of the staggered incremental unknowns.
ISSN: 0168-9274

hal-00770268
https://hal.univ-antilles.fr/hal-00770268
DOI : 10.1016/S0168-9274(99)00044-6

Éditeur(s) : HAL CCSD
Résumé : International audience
To solve general variational inequalities considered in Robinson [9], we propose a generalized version of an algorithm introduced by Bermudez and Moreno [3]. Our results extend, improve and develop some known results in this field.
Advanced Modeling and Optimization

hal-00783892
https://hal.univ-antilles.fr/hal-00783892

Éditeur(s) : HAL CCSD
Résumé : The midpoint method was previously used in the solving of equations and in this work, the aim is to adapt the theory to the set-valued analysis in order to approach solutions of generalized equations of the form 0_inf(x)+F(x). In particular, we show the existence and convergence fo sequences provided the second order derivative of the function f satisfies a Hölder condition, or a center-Hölder condition.
GDR MOA
Sainte-Anne, Guadeloupe

hal-00757686
https://hal.archives-ouvertes.fr/hal-00757686

Éditeur(s) : HAL CCSD
Résumé : International audience
We deal with a perturbed version of a Hummel-Seebeck type method to approximate a solution of variational inclusions of the form : 0 ∈ Φ(z) + F(z) where Φ is a single-valued function twice continuously Fréchet differentiable and F is a set-valued map from Rn to the closed subsets of Rn. This framework is convenient to treat in a unified way standard sequential quadratic programming, its stabilized version, sequential quadratically constrained quadratic programming, and linearly constrained Lagrangian methods (see [1]). We obtain, thanks to some semistability and another property (which is close to the hemistability) of the solution z ̄ of the previous inclusion, the local existence of a sequence that is superquadratically or cubically convergent.
ISSN: 2518-3680

hal-01630560
https://hal.archives-ouvertes.fr/hal-01630560
DOI : 10.22606

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
In this paper, the generalized Stokes problem αu−νΔu+∇p=f, ∇u=0, is considered, where ν denotes the kinematic viscosity, α is a positive parameter proportional to the inverse of the time-step, and the source term f gathers the external forcing, the nonlinear term, and the explicit part of the linear term. The system is derived from a time discretization for the Navier-Stokes equation governing the motion of a two-dimensional incompressible fluid. A domain decomposition numerical method is developed for solving the system. The original domain is divided into several nonoverlapping subdomains, and in each subdomain the concerned equations are discretized by certain finite element methods. A new feature of the method is that the pressure p is required to be piecewise linear rather than piecewise constant, so that the nonphysical oscillations in the solution using piecewise linear pressure are eliminated. However, a difficulty in using piecewise linear pressure is that the Stokes problem in each subdomain involves Dirichlet boundary conditions on pressure at the interface, which is not a real Stokes problem. To avoid the difficulty, a modification is proposed which removes the continuity conditions on the pressure across the interface. In this way, the Stokes problem in each subdomain has only Dirichlet boundary conditions on the velocity. Formulations and discussions for both the methods are presented, which shows that the modified method is simpler than the original one. Numerical experiments are displayed to show the efficiency of the methods, especially that the modified method has the same accuracy as the original one.
ISSN: 0749-159X

hal-00730200
https://hal.archives-ouvertes.fr/hal-00730200

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
We mainly study a system of two coupled nonlinear Schrödinger equations where one equation includes gain and the other one includes losses. This model constitutes a generalization of the model of pulse propagation in bire-fringent optical fibers. We answered partially to a question of some authors in [8], that in the Manakov case, the solution stays in L 2 (0, T ; H 1), that means that the solution can not blow up in finite time. More precisely, the bound that is provided in this paper does not seem to be optimal but different than those that has been given from a previous study [8]. Thanks to the way we treat the a priori estimate, we obtain a sharp bound in L 2 (0, T ; H 1), which would be difficult to reach from the study of other authors [8]. The result is illustrated by numerical results which have been obtained with a finite element solver well adapted for that purpose.
ISSN: 0022-2526

Droits : http://creativecommons.org/licenses/by/
hal-01270459
https://hal.archives-ouvertes.fr/hal-01270459
https://hal.archives-ouvertes.fr/hal-01270459/document
https://hal.archives-ouvertes.fr/hal-01270459/file/paperver2.pdf

Résumé : Cette thèse a pour objet l'étude de la contrôlabilité à zéro de systèmes d'équations aux dérivées partielles paraboliques, que l'on rencontre en physique, chimie ou en biologie. En chimie ou en biologie, ces systèmes modélisent l'évolution au cours du temps d'une concentration chimique ou de la densité d'une population (de bactéries, de cellules). Le but de la contrôlabilité à zéro est d'amener la solution du système à l'état nul à un temps donné T, en agissant sur le système à l'aide d'un contrôle. Nous recherchons donc un contrôle, de norme minimale, tel que la solution associée y vérifie y(T)=O dans le domaine Omega considéré. Les problèmes de contrôlabilité à zéro considérés dans cette thèse sont de trois types. Dans un premier temps, nous nous intéressons à la contrôlabilité à zéro avec un nombre fini de contraintes sur la dérivée normale de l'état, pour l'équation de la chaleur semi-linéaire. Puis, nous analysons la contrôlabilité simultanée à zéro avec contrainte sur le contrôle, pour un système linéaire de deux équations paraboliques couplées. Notre dernière étude concerne la contrôlabilité à zéro d'un système non linéaire de deux équations paraboliques couplées. Nous abordons ces problèmes de contrôlabilité principalement à l'aide d'inégalités de Carleman. En effet, l'étude des problèmes de contrôlabilité à zéro, et plus généralement de contrôlabilité exacte, peut se ramener à l'établissement d'inégalités d'observabilité pour le problème adjoint, conséquences d'inégalités de Carleman. Nous construisons le contrôle optimal en utilisant la méthode variationnelle et nous le caractérisons par un système d'optimalité
This thesis is devoted to the study of the null controllability of systems of parabolic partial differential equations, which we meet in physics, chemistry or in biology. In chemistry or in biology, the se systems model the evolution in time of a chemical concentration or the density of a population (of bacteria, cells). The aim of nu Il controllability is to lead the solution of the system to zero in a given time T, by acting on the system with a control. Thus we are looking for a control, of minimal norm, such as the associated solution y satisfies y(T)=O in the domain Omega under concern. We consider three types of null controllability problems in this thesis. At first, we are interested in the null controllability with afinite number of constraints on the normal derivative of the state, for the serni-Iinear heat equation. Then, we analyze the simultaneous null controllability with constraint on the control, for a linear system of two coupled parabolic equations. Our last study deals with the null controllability ofa non linear system oftwo coupled parabolic equations. We approach these controllability problems mainly by means of Carleman's inequalities. Indeed, the study of null controllability problems, and more generally exact controllability problems, is equivalent to obtain observability inequalities for the adjoint problem, consequences of Carleman's inequalities. We build the optimal controlusing the variationnal method and we characterize it by an optimality system

http://www.theses.fr/2013AGUY0609/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The main purpose of this paper is to propose a deterministic mathematical model with control variable which describes the spatiotemporal spread of emph{Salmonella} within a laying flock. This model assume an indirect transmission of the disease within the flock through the bacteria density in the environment. We provide a mathematical analyze of the null controllability of the model: we begin to construct a family of solutions to the linear null-controllability problem using the the Carleman inequality. Then, by a generalized Leray-Shauder fixed point theorem, we show that one can bring the system to rest at final time T.
ISSN: 0307-904X

Droits : info:eu-repo/semantics/OpenAccess
hal-01683267
https://hal.univ-antilles.fr/hal-01683267
https://hal.univ-antilles.fr/hal-01683267/document
https://hal.univ-antilles.fr/hal-01683267/file/APM-S-13-02490-1.pdf

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The aim of this study is the approximation of a solution x* of a ganeralized equation 0 in f(x)+F(x) in Banach spaces, where f is a single-valued function whose second order Frechet derivative satisfies an Hölder condition and F stands for a set-valed map with closed graph. Using a fixed point theorem and the Aubin property of F, we show the existence and the superquadratic convergence of a sequence derived from a midpoint method.
ISSN: 0167-8019

hal-00642118
https://hal.archives-ouvertes.fr/hal-00642118

Éditeur(s) : HAL CCSD Tsing Hua University
Résumé : International audience
This paper deals with variational inclusions of the form : $0in varphi(z)+F(z)$ where $varphi$ is a single-valued function admitting a second order Fréchet derivative and $F$ is a set-valued map from $R^q$ to the closed subsets of $R^q$. In order to approximate a solution $bar z$ of the previous inclusion, we use an iterative scheme based on a multipoint method. We obtain, thanks to some semistability properties of $bar z$, local superquadratic or cubic convergent sequences
ISSN: 1607-2510

hal-00728816
https://hal.archives-ouvertes.fr/hal-00728816

Éditeur(s) : HAL CCSD
Résumé : International audience
The author proposes a generalized proximal method for solving an equilibrium problem which consists in finding x 2 K such that F(x, y) 0, for all y 2 K, where K is a nonempty, convex and closed set of a real Hilbert space X, and F:K ×K !Ris a given bifunction with F(x, x) = 0 for all x 2 K. The weak convergence of the sequence generated by the method is proved under the assumptions of monotonicity and convexity, with respect to the second argument y (for every fixed x 2 K), of the bifunction F. Replacing the assumption of monotonicity with the one of strong monotonicity on F, a strong convergence result is obtained. A second strong convergence theorem is proved under the hypotheses of monotonicity and a new assumption of "co-Lipschitz continuity at 0" of the operator F. Applications to convex optimization, to the problem of finding a zero of a maximal monotone operator and to Nash equilibria problems are provided.
Journal of Natural Geometry

hal-00773194
https://hal.univ-antilles.fr/hal-00773194

Résumé : Selon les théories classiques du pouvoir, les relations asymétriques favorisent généralement l’acteur le plus puissant en termes de ressources. Toutefois, la partie la plus puissante au niveau de la force et des ressources ne gagne pas toujours dans les négociations. Cela dépend de plusieurs facteurs et notamment des tactiques de négociation de la partie la plus faible. Notre thèse vise justement à analyser un certain nombre de stratégies de négociations que peuvent mener les parties les plus faibles pour obtenir des gains. Afin d’illustrer nos propos, nous avons choisi l’exemple donné par un certain nombre de pays en voie de développement (PVD) pour contester le brevet sur le vivant contenu dans l’Accord sur les aspects des droits de la propriété intellectuelle (ADPIC). Notre objectif a été de comprendre les principales stratégies qu’ils ont employées pour remettre en question cette norme et la rééquilibrer. Afin de réaliser ce travail, nous nous sommes servis du concept d’hégémonie de Gramsci et de cadre emprunté à la littérature des mouvements sociaux. Cela nous a permis de poser l’hypothèse selon laquelle l’Accord sur les ADPIC constitue une norme hégémonique qui avantage essentiellement quelques pays développés et des entreprises internationales. Cependant, cette domination se cache derrière un discours universel et positif visant à susciter une forte adhésion. Ainsi, dans un tel cas de figure, les PVD ne peuvent pas espérer la remettre en question sans un changement de perception. Il faut donc que les règles perçues comme justes et immuables soient cadrées comme injustes et mutables, pour que les pays décident de les contester. Nous avons alors testé cette hypothèse à travers une analyse de contenu du discours officiel des PVD à l’Organisation mondiale du commerce. Ce travail nous a permis d’observer que le cadrage est un instrument important pour lutter contre l’hégémonie d’une norme. En effet, il offre la faculté de montrer que le brevet sur le vivant, loin de présenter que des avantages, est aussi une source de problèmes auxquels il faut apporter des solutions. Le cadre constitue aussi un bon moyen pour élaborer des propositions normatives alternatives. Toutefois, nous avons constaté que cette stratégie est insuffisante pour traduire les propositions des PVD en normes contraignantes. Afin d’obtenir certains changements normatifs, l’élaboration de coalitions s’avère particulièrement pertinente pour les PVD. De même, nous avons noté que les PVD qui demandent des changements normatifs quand la structure des opportunités politiques est ouverte ont plus de chance d’obtenir satisfaction de leurs revendications. La présente thèse nous offre ainsi un portrait général de stratégies de négociation et démontre que sous certaines conditions les parties les plus faibles peuvent obtenir certains gains dans une négociation asymétrique.
According to the classical theories of power, asymmetrical relations generally favor the most powerful actor in terms of resources. However, the most powerful in terms of strength and resources part does not always win in negotiations. This depends on several factors, including negotiation tactics of the weaker party. Our thesis aims to analyze different type of negotiation strategies that weaker parties can use to obtain some benefit. To illustrate this point, we chose the example set by a number of developing countries (DV) to challenge the patenting of life contained in the Agreement on Trade-Related Aspects of Intellectual Property Rights (TRIPS). Our goal was to understand the key strategies they have used to question this norm and rebalance it. To make this work, we used the concept of hegemony conceptualized by Gramsci and the concept of framework borrowed from the literature of social movements. This tool has allowed us to make the assumption that TRIPS is a hegemonic norm that mainly benefit to few developed countries and international companies. However, this domination is hidden by the norms thanks to universal and positive discourse which help to generate strong adhesion. Thus, in such a case, developing countries can’t expect to challenge this norm without a change of perception. It is therefore necessary that the rules perceived as fair and immutable are framed as unjust and mutable, so that countries decide to challenge it. We then tested this hypothesis through a content analysis of the DC’s official discourse at the World Trade Organization. This work has allowed us to observe that the framing is an important tool in the fight against the norm’s hegemony. Indeed, it offers the possibility to show that the patenting of life, far from presenting just a source of benefits, is also a source of problems that need solutions. The frame is also a good way to develop alternative normative propositions. However, we found that this strategy is insufficient to translate DC’s proposals into binding norms. In order to obtain changes in the agreement, building coalitions is particularly relevant for DC. Furthermore, we noted that DC which require regulatory changes when the structure of political opportunities is opened are more likely to obtain what they want. This thesis offers us a general picture of negotiations strategies and reveal that under certain conditions the weaker parties can get some gains in an asymmetrical negotiation.

http://www.theses.fr/2013AGUY0642/document

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The aim of this paper is twofold. First, it is to extend the sensitivity analysis framework, developed recently for variational inequalities, to mixed equilibrium problems. The second is to propose iterative methods for solving this kind of problems. In the process, we establish an equivalence between an extended version of Wiener-Hopf equations and the given problems relying on a generalization of the Yosida approximation notion. Our results generalize results obtained for optimization, variational inequalities, complementarity problems, and problems of Nash equilibria.
ISSN: 0898-1221

hal-00779234
https://hal.univ-antilles.fr/hal-00779234
DOI : 10.1016/S0898-1221(02)00218-3

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
This article is concerned with a generalization of the hybrid steepest descent method from variational inequalities to the multivalued case. This will be reached by replacing the multivalued operator by its Yosida approximate, which is always Lipschitz continuous. It is worth mentioning that the hybrid steepest descent method is an algorithmic solution to variational inequality problems over the fixed point set of certain nonexpansive mappings and has remarkable applicability to the constrained nonlinear inverse problems like image recovery and MIMO communication systems
ISSN: 0163-0563

hal-00776641
https://hal.univ-antilles.fr/hal-00776641
DOI : 10.1080/01630563.2011.619676

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
With the help of differential algebras of(C,Ep)-type, we construct an algebra of generalized functions which allows us to solve a Gourmet problem with irregular data. For this problem, we perform a qualitative study when the data are Dirac functions.
ISSN: 1065-2469

hal-01545673
https://hal.archives-ouvertes.fr/hal-01545673