Éditeur(s) : HAL CCSD IOP Publishing
Résumé : International audience
Based on the very recent work by Censor and Segal (2009 J. Convex Anal. 16 587-600) and inspired by Xu (2006 Inverse Problems 22 2021-34) and Yang (2004 Inverse Problems 20 1261-6), we investigate an algorithm for solving the split common fixed-point problem for the class of demicontractive operators in a Hilbert space. Our results improve and/or develop previously discussed feasibility problems and related algorithms. It is worth mentioning that the convex feasibility formalism is at the core of the modeling of many inverse problems and has been used to model significant real-world problems, for instance, in sensor networks, in radiation therapy treatment planning, in computerized tomography and data compression, see Censor et al (2006 Phys. Med. Biol. 51 2353-65) and Combettes (1996 Adv. Imaging Electron. Phys. 95 155-270) and references therein.
ISSN: 0266-5611

hal-00778174
https://hal.univ-antilles.fr/hal-00778174
DOI : 10.1088/0266-5611/26/5/055007

Éditeur(s) : HAL CCSD
Résumé : International audience
Panamerican Mathematical Journal

hal-00814853
https://hal.univ-antilles.fr/hal-00814853

Éditeur(s) : HAL CCSD Yokohama
Résumé : International audience
We make use of the viscosity technique to develop a convergent method for approximating a common element of the set of fixed points of a demicontractive operator and the set of solutions of a monotone equilibrium problem. The proposed algorithm is obtained by coupling a modified hybrid steepest descent method with the extragradient algorithm. Under mild conditions, the strong convergence of the sequences generated by the algorithm is obtained. Using this result we obtain two corollaries which improve or develop several corresponding results in this field.
Journal of Nonlinear and Convex Analysis

hal-00779988
https://hal.univ-antilles.fr/hal-00779988

Éditeur(s) : HAL CCSD
Résumé : International audience
J. Convex Anal.

hal-00695362
https://hal.archives-ouvertes.fr/hal-00695362

Éditeur(s) : HAL CCSD Wiley
Résumé : Proper estimates of decomposition are essential for tropical forests, given their key role in the global carbon (C) cycle. However, the current paradigm for litter decomposition is insufficient to account for recent observations and may limit model predictions for highly diverse tropical ecosystems. In light of recent findings from a nutrient-poor Amazonian rainforest, we revisit the commonly held views that: litter traits are a mere legacy of live leaf traits; nitrogen (N) and lignin are the key litter traits controlling decomposition; and favourable climatic conditions result in rapid decomposition in tropical forests. Substantial interspecific variation in litter phosphorus (P) was found to be unrelated to variation in green leaves. Litter nutrients explained no variation in decomposition, which instead was controlled primarily by nonlignin litter C compounds at low concentrations with important soil fauna effects. Despite near-optimal climatic conditions, tropical litter decomposition proceeded more slowly than in a climatically less favourable temperate forest. We suggest that slow decomposition in the studied rainforest results from a syndrome of poor litter C quality beyond a simple lignin control, enforcing energy starvation of decomposers. We hypothesize that the litter trait syndrome in nutrient-poor tropical rainforests may have evolved to increase plant access to limiting nutrients via mycorrhizal associations.
ISSN: 0028-646X

hal-01032400
https://hal.archives-ouvertes.fr/hal-01032400
DOI : 10.1111/j.1469-8137.2010.03483.x

Éditeur(s) : HAL CCSD De Gruyter
Résumé : International audience
The data available in the literature concerning wood cutting forces permit to build models or to simulate the main wood machining processes (milling, sawing, peeling etc.). This approach contributes to a better understanding of formation of wood surfaces and chips and the data may be helpful to optimize cutting geometry, reduce tool wear, improve tool material, and to size tool-machines. The models may also be useful for industrial application in two ways: (1) providing data to optimise the settings for a given operation (batch approach) and (2) building predictive models that could be the basis of an online control systems for the machining processes (interactive approach). A prerequisite for this is that numerous machining tests on different wood materials are performed based on experiences with different kind of tools and experimental devices. With potential industrial applications in focus, the emphasis of this review was on the wood peeling process, which is a very demanding special case of wood cutting. Though not so many industrial machines are equipped with expensive force sensors, there is a lot of high quality information available about cutting forces which may be useful to improve the scientific or technologic knowledge in wood machining. Alternative parameters, such as vibration or sound measurements, appear to be promising substitutes in the praxis, particularly to feed online control systems of any wood cutting process.
ISSN: 0018-3830

hal-00876003
https://hal.archives-ouvertes.fr/hal-00876003
https://hal.archives-ouvertes.fr/hal-00876003/document
https://hal.archives-ouvertes.fr/hal-00876003/file/LABOMAP_Holzforschung_2009_denaud.pdf
ENSAM : http://hdl.handle.net/10985/7419

Éditeur(s) : Elsevier
Résumé : In the Gulf of Gabes (Tunisia, Eastern Mediterranean sea), the grooved carpet shell Ruditapes decussatus has been seen to contain persistent levels of gymnodimine (GYM) for several years. The present experimental work represents the first attempt to assess detoxification kinetics of fast-acting toxins (FAT) in marine molluscs fed specific diets of non-toxic algae (Isochrysis galbana). To find an optimal detoxification method, two experiments were performed in which clams were first fed the toxic dinoflagellate Karenia selliformis to artificially contaminate them with GYM, thus simulating the effect of natural toxic episodes. As a second step, the same clams were fed a non-toxic algae, I. galbana. to speed up the detoxification process. Changes in toxin content over the whole experiment were assessed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis. The first results revealed (i) faster detoxification rates in digestive gland (DG) when clams were fed on L galbana compared with a starved control (no food) and (ii) a typical detoxification pattern, i.e. a rapid drop in toxin content within the first days followed by a secondary slower decrease. GYM levels could be reduced approximately to less than 5% within 7-8 days in clams fed I. galbana, according to the initial toxin levels of 1400 and 9400 mu g GYM/kg of DG, respectively. At the end of the second experiment, DSP mouse bioassay was negative when GYM was less than 100 mu g/kg DG. (C) 2009 Elsevier B.V. All rights reserved.
Harmful Algae (1568-9883) (Elsevier), 2010-02 , Vol. 9 , N. 2 , P. 200-207

Droits : 2010 Elsevier Ltd All rights reserved.
http://archimer.ifremer.fr/doc/2010/publication-7488.pdf
DOI:10.1016/j.hal.2009.10.002
http://archimer.ifremer.fr/doc/00000/7488/

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The aim of this work is to propose viscosity approximation methods which amounts to selecting a particular fixed-point of a given nonexpansive self-mapping.
Journal of Mathematical Analysis and applications

hal-00776600
https://hal.univ-antilles.fr/hal-00776600
DOI : 10.1006/jmaa.1999.6615

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 1862-4472

hal-01361488
https://hal.archives-ouvertes.fr/hal-01361488
DOI : 10.1007/s11590-016-1079-4

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Given a pair of Banach spaces X and Y such that one is the dual of the other, we study the relationships between generic Fréchet differentiability of convex continuous functions on Y (Asplund property), generic existence of linear perturbations for lower semicontinuous functions on X to have a strong minimum (Stegall variational principle), and dentability of bounded subsets of X (Radon-Nikodým Property).
ISSN: 0927-6947

hal-00694604
https://hal.archives-ouvertes.fr/hal-00694604

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Two splitting procedures for solving equilibrium problems involving the sum of two bifunctions are proposed and their convergence is established under mild assumptions.
Journal of Mathematical Analysis and applications

hal-00779982
https://hal.univ-antilles.fr/hal-00779982
DOI : 10.1016/j.jmaa.2009.06.005

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
ISSN: 1385-1292

hal-00606656
https://hal.archives-ouvertes.fr/hal-00606656

Éditeur(s) : HAL CCSD PubMed
Résumé : International audience
The aim of this study was to measure the heart rate (HR) response of eight elite water polo players during the four 7-min quarters of the game and to check for relationships with the physiological parameters of performance ( ·VO2max, Th1vent, Th2vent). Each athlete performed a ·VO2max treadmill test and played a water polo game wearing a heart rate monitor. The game fatigue index was calculated as the ratio of the fourth-quarter HR to the first-quarter HR: HR4/HR1. The results showed a slight decrease in fourth-quarter HR compared with the first quarter, with the mean four-quarter HR equal to 79.9 ± 4.2% of HRmax. Stepwise multiple regression analysis showed ·VO2max to be the main explanatory factor of game intensity, i.e. game HR expressed in %HRreserve (R=0.88, P<0.01). We observed that higher aerobic capacity resulted in higher game intensity. We also observed a decrease in the playing intensity in the fourth quarter compared with the first, likely due to very high game involvement. We concluded that high aerobic capacity seems necessary to ensure high game intensity in water polo. This suggests that coaches should encourage their athletes to reach a minimum level of ·VO2max and that HR monitoring could be of great interest in the control of water polo training sessions.
ISSN: 0860-021X

hal-01158208
https://hal.univ-antilles.fr/hal-01158208
DOI : 10.5604/20831862.1083277

Éditeur(s) : HAL CCSD University of Szeged, Bolyai Institute
Résumé : International audience
We consider the semilinear heat equation in a boundeddomain of R^m. We prove the null controllability of the systemwith a finite number of constraints on the normal derivative, whenthe control acts on a bounded subset of the domain. First, weshow that the problem can be transformed into a null controllabilityproblem with constraint on the control, for a linear system.Then, we use an appropriate observability inequality to solve thelinearized problem. Finally, we prove the main result by means ofa fixed-point method.
ISSN: 1417-3875

hal-01679144
https://hal.archives-ouvertes.fr/hal-01679144
DOI : 10.14232/ejqtde.2012.1.95

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
ISSN: 0362-546X

hal-00780893
https://hal.univ-antilles.fr/hal-00780893

Éditeur(s) : HAL CCSD Heldermann
Résumé : International audience
We study extended notions for sums of monotone operators and for precompositions of monotone operators with continuous linear mappings. First, we establish some new properties related to the notion of extended sum recently proposed by Revalski and Théra, among them the monotonicity of this sum provided the operators involved are maximal monotone. Then, we show that the equivalence which exists between usual sums and compositions remains valid also for the extended operations. This allows us to obtain some known and new results for extended compositions via the corresponding properties of extended sums.
Journal of Convex Analysis

hal-00698807
https://hal.archives-ouvertes.fr/hal-00698807

Éditeur(s) : HAL CCSD School of Communications and Informatics
Résumé : International audience
An approximate procedure for solving equilibrium problems is proposed and its convergence is established under natural conditions. The result obtained in this paper includes, as a special case, some known results in convex minimization and monotone inclusion fields.
ISSN: 1443-5756

hal-00780881
https://hal.univ-antilles.fr/hal-00780881

Éditeur(s) : HAL CCSD
Résumé : International audience
Relying on an idea of T. Pennanen, we use a localized version of maximal hypomonotonicity, and prove that it is enough to guarantee the local convergence of the Tikhonov regularization. In the process, we revisit this method which together with the help of the analysis developed by T. Pennanen allows us to obtain the desired result.
Mathematical Inequalities and Apllications

hal-00779258
https://hal.univ-antilles.fr/hal-00779258

Éditeur(s) : HAL CCSD
Résumé : International audience
Computers & Mathematics with Applications

hal-01683259
https://hal.univ-antilles.fr/hal-01683259
DOI : 10.1016/j.camwa.2011.03.025

Éditeur(s) : HAL CCSD School of Communications and Informatics
Résumé : International audience
The hybrid proximal point algorithm introduced by Solodov and Svaiter allowing significant relaxation of the tolerance requirements imposed on the solution of proximal subproblems will be combined with the inertial method introduced by Alvarez and Attouch which incorporates second order information to achieve faster convergence. The weak convergence of the resulting method will be investigated for finding zeroes of a maximal monotone operator in a Hilbert space.
ISSN: 1443-5756

hal-00780745
https://hal.univ-antilles.fr/hal-00780745
https://hal.univ-antilles.fr/hal-00780745/document
https://hal.univ-antilles.fr/hal-00780745/file/170_03_www.pdf