Éditeur(s) : HAL CCSD Wiley
Résumé : A standardized rapid inventory method providing information on both tree species diversity and aboveground carbon stocks in tropical forests will be an important tool for evaluating efforts to conserve biodiversity and to estimate the carbon emissions that result from deforestation and degradation (REDD). Herein, we contrast five common plot methods differing in shape, size, and effort requirements to estimate tree diversity and aboveground tree biomass (AGB). We simulated the methods across six Neotropical forest sites that represent a broad gradient in forest structure, tree species richness, and floristic composition, and we assessed the relative performance of methods by evaluating the bias and precision of their estimates of AGB and tree diversity. For a given sample of forest area, a several small' (<1ha) sampling strategy led to a smaller coefficient of variation (CV) in the estimate of AGB than a few large' one. The effort (person-days) required to achieve an accurate AGB estimate (<10% CV), however, was greater for the smallest plots (0.1ha) than for a compromise approach using 0.5ha modified Gentry plots, which proved to be the most efficient method to estimate AGB across all forest types. Gentry plots were also the most efficient at providing accurate estimates of tree diversity (<10% CV of Hill number). We recommend the use of the 0.5ha modified Gentry plot method in future rapid inventories, and we discuss a set of criteria that should inform any choice of inventory method.
ISSN: 0006-3606

hal-01032408
https://hal.archives-ouvertes.fr/hal-01032408
DOI : 10.1111/btp.12006

Éditeur(s) : HAL CCSD Oxford University Press (OUP): Policy P - Oxford Open Option A Oxford University Press (OUP)
Résumé : International audience
It is well known that sedimentary rocks having same porosity can have very different pore size distribution. The pore distribution determines many characteristics of the rock, among which its transport properties are often the most useful. Multifractal analysis is a powerful tool that is increasingly used to characterize the pore space. In this study, we performed multifractal analysis of pore distribution on simulated sedimentary rocks using the relaxed bidisperse ballistic deposition model (RBBDM). The RBBDM can generate a 3-D structure of sedimentary rocks of variable porosity by tuning the fraction p of particles of two different sizes. We also performed multifractal analysis on two samples of real sedimentary rock to compare with the simulation studies. One sample, an oolitic limestone is of high porosity (40 per cent) while the other is a reefal carbonate of low porosity, around 7 per cent. 2-D sections of X-ray microtomographs of the real rocks were stacked sequentially to reconstruct the real rock specimens. Both samples show multifractal character. The results from analysis of real rock agree quite well with the simulated structure of low porosity. The simulated rock of high porosity showed a weak multifractal nature though the real rock sample of similar porosity was found to be strongly multifractal. We propose a ‘structure parameter’ ξ which is a function of porosity and the generalized dimensions, and controls the transport properties of the rock.
ISSN: 0956-540X

hal-01174142
https://hal.archives-ouvertes.fr/hal-01174142
DOI : 10.1093/gji/ggu417

Éditeur(s) : HAL CCSD
Résumé : International audience
Structure and evolution of networks have been areas of growing interest in recent years, especially with the emergence of Social Network Analysis (SNA) and its application in numerous fields. Researches on diffusion are focusing on network modeling for studying spreading phenomena. While the impact of network properties on spreading is now widely studied, involvement of network dynamicity is very little known. In this paper, we address the epidemiology context and study the consequences of network evolutions on spread of diseases. Experiments are conducted by comparing incidence curves obtained by evolution strategies applied on two generated and two real networks. Results are then analyzed by investigating network properties and discussed in order to explain how network evolution influences the spread. We present the MIDEN framework, an approach to measure impact of basic changes in network structure, and DynSpread, a 2D simulation tool designed to replay infections scenarios on evolving networks.
Database and Expert Systems Applications - 22nd International Conference, DEXA 2011, Toulouse, France, August 29 - September 2, 2011, Proceedings, Part II
Toulouse, France

hal-00614925
https://hal.archives-ouvertes.fr/hal-00614925
DOI : 10.1007/978-3-642-23091-2_49

Éditeur(s) : Ecole Nationale Supérieure Agronomique de Rennes
Résumé : Long-line fishing has been growing on the island of La Réunion since the beginning of the 1990s. The target species is the swordfish (Xiphias gladius), fished mainly in the tropical waters surrounding the island between longitudes 45 degree E and 60 degree E, and latitudes 17 degree S and 27 degree S. From 1998 to 2000, a finalised research programme enabled the collection of precise data concerning the lines' positions and the parameters of the fishing efforts: 3,602 nettings were thus informed by the catches (in numbers of individuals caught) and 12 descriptive variables of the effort. In parallel with this collection effort, satellite maps that described the ocean's landscape of this region of the Indian Ocean exploited by La Réunion's fisheries were made available to sailors and scientists. Extractions from these environmental variables were made at the fishing lines' positions, which allowed us to propose 20 variables describing the environmental conditions of swordfish catches applied to the nettings. In an early part of this study, after a descriptive analysis and a first selection of the variables, we used several GAM (Generalised Additive Models) to model the respective effects of effort and environmental variables on the variability of swordfish catches. We thus highlighted the predominance of factors linked to fishermen (fishing effort) on oceanographic factors in the explanation of this variability. Following these results, a summary on the biology and ecology of the swordfish was proposed in order to draw up hypotheses on the characteristics of this species' population in the Indian Ocean. The aspects linked to the individual behaviour and movements of the population were particularly highlighted. In a latter part of this study and in order to complete the empirical approach by an exploratory constructivist approach, we proposed a modelling tool in order to simulate the possible movements of individuals within the oceanic landscape described by the available satellite maps. After reading in the literature about the various forms of modelling the movements of the large pelagics, we developed an original computer modelling architecture of the multi-agent type that made it possible to manipulate in a dynamic way the satellite maps (and derived products), the individual movements of "animats" whose behaviours were based on this environmental information, and agents that clarify the process of long-line fishing in a geographical way. The computer model that was implemented (MUFINS, for MUlti-Fish INdian ocean Simulator) was next used by calibrating the behaviour of the animats on the real data originally from the analysis of commercial catches proposed in the first part, using robust techniques based on fuzzy logic. The results of the simulations were compared, on the one hand, with the large-scale hypotheses of movement proposed in the first part, and, on the other hand, to swordfish catches both real and corrected for the effect of the fishing effort modelled by the GAM models. Even if the results of these simulations in this study do not allow for proposing convincing interpretations of the underlying processes, the MUFINS tool showed its ability to address questions associated with the swordfish's behaviour in the tropical oceanic landscape and to the effects of scale transfers between the individual level and the collective level. We now envisage its use in a more operational framework, as an interface for dialogue between fishermen and scientists with a goal of sustainable management of the resource.
La peche palangriere s'est developpee a l'ile de La Reunion depuis le debut des annees 1990. L'espece cible est l'espadon (Xiphias gladius), principalement exploite dans les eaux tropicales autour de l'ile entre les longitudes 45 degree E et 60 degree E, et les latitudes 17 degree S et 27 degree S. De 1998 a 2000, un programme de recherche finalisee a permis de collecter des informations precises concernant les positions des lignes et les parametres de l'effort de peche : 3602 filages sont ainsi renseignes par les captures (en nombre d'individus captures) et 12 variables descriptives de l'effort. En parallele de cet effort de collecte, des cartes satellitales ont pu etre mises a la disposition des marins et des scientifiques, decrivant le paysage oceanique de cette region de l'ocean Indien exploitee par la pecherie reunionnaise. Des extractions de ces variables environnementales ont ete effectuees aux positions des lignes de peche, nous permettant de proposer 20 variables descriptives des conditions environnementales de captures d'espadon appliquees aux filages. Dans une premiere partie de ce travail, apres une analyse descriptive et une premiere selection des variables, on a modelise par plusieurs modeles GAM (Generalized Additive Models) les effets respectifs des variables d'effort et des variables environnementales sur la variabilite des captures d'espadon. On a ainsi mis en evidence la predominance des facteurs lies aux pecheurs (effort de peche) sur les facteurs oceanographiques dans le caractere explicatif de cette variabilite. A la suite de ces resultats, une synthese sur la biologie et l'ecologie de l'espadon a ete proposee afin de degager des hypotheses sur les caracteristiques de la population de cette espece dans l'ocean Indien. Les aspects lies au comportement individuel et aux deplacements de la population ont ete particulierement mis en evidence. Dans une deuxieme partie de ce travail et afin de completer l'approche empirique par une approche constructiviste exploratoire, nous avons propose un outil de modelisation afin de simuler les deplacements possibles d'individus au sein du paysage oceanique decrit par les cartes satellitales disponibles. Apres avoir passe en revue dans la litterature les differentes formes de modelisation des deplacements des grands, pelagiques, nous avons developpe une architecture originale de modelisation informatique de type multi-agents permettant de manipuler de maniere dynamique les cartes satellitales (et les produits derives), les mouvements individuels < d'animats >, dont les comportements sont bases sur cette information environnementale, et des agents qui explicitent le processus de capture palangriere de maniere geographique. Le modele informatique ainsi implemente (MUFINS, pour MUlti-Fish INdian ocean Simulator) a ensuite ete utilise en calibrant les comportements des animats sur les donnees reelles issues de l'analyse des captures commerciales proposee en premiere partie, a partir de techniques robustes basee sur la logique floue. Les resultats des simulations ont ete confrontes d'une part aux hypotheses de deplacement a grande echelle proposees en premiere partie, et d'autre part aux captures d'espadon reelles et corrigees de l'effet de l'effort de peche modelise par les modeles GAM. Meme si les resultats de simulations presentes dans ce travail ne permettent pas de proposer d'interpretations convaincantes des processus sous-jacents, l'outil MUFINS a demontre son aptitude a aborder les questions liees au comportement de l'espadon dans le paysage oceanique tropical et aux effets des transferts d'echelle entre le niveau individuel et le niveau collectif. On envisage desormais son utilisation dans un cadre plus operationnel, comme interface de dialogue entre les pecheurs et les scientifiques a des fins de gestion durable de la ressource.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2005/these-2592.pdf
http://archimer.ifremer.fr/doc/00000/2592/

Éditeur(s) : Oxford Univ Press
Résumé : Spatio-seasonal explicit simulation models can predict the impact of spatial management measures on marine fish populations and fishing activities. As fisheries are complex systems, fisheries simulation models are often complex, with many uncertain parameters. Here, the methodology is provided to deliver fishery diagnostics within an uncertainty context using a complex simulation tool. A sensitivity analysis of the model is performed on model outputs using partial least-squares to identify the most sensitive parameters. The impact of several management measures is then simulated using a statistical simulation design taking into account the uncertainty of the selected sensitive parameters. This approach was applied to the Bay of Biscay anchovy stock using the ISIS-Fish (Integration of Spatial Information for Simulation of Fisheries) model to assess the impact of imposing marine protected areas (MPAs) conditionally on parameter uncertainty. The diagnostic appeared to be highly sensitive to the mortality of larvae and juveniles, growth, and reproduction. The uncertainty of the values of these parameters did not permit any of the simulated MPA designs to be proposed. However, according to anchovy catch and biomass, the simulations allowed the low impact of closure duration to be shown and underscored the utility of protecting such key processes as spawning.
Ices Journal Of Marine Science (1054-3139) (Oxford Univ Press), 2010-07 , Vol. 67 , N. 5 , P. 1063-1075

Droits : 2010 ICES/CIEM. Oxford journals
http://archimer.ifremer.fr/doc/00011/12234/9281.pdf
DOI:10.1093/icesjms/fsq002
http://archimer.ifremer.fr/doc/00011/12234/

Éditeur(s) : Blackwell science
Résumé : This paper deals with the design of modelling tools suitable for investigating the consequences of alternative policies on the dynamics of resources and fisheries, such as the evaluation of marine protected areas (MPA). We first review the numerous models that have been developed for this purpose, and compare them from several standpoints: population modelling, exploitation modelling and management measure modelling. We then present a generic fisheries simulation model, Integration of Spatial Information for FISHeries simulation (ISIS-Fish). This spatially explicit model allows quantitative policy screening for fisheries with mixed-species harvests. It may be used to investigate the effects of combined management scenarios including a variety of policies: total allowable catch (TAC), licenses, gear restrictions, MPA, etc. Fisher's response to management may be accounted for by means of decision rules conditioned on population and exploitation parameters. An application to a simple example illustrates the relevance of this kind of tool for policy screening, particularly in the case of mixed fisheries. Finally, the reviewed models and ISIS-Fish are discussed and confronted in the light of the underlying assumptions and model objectives. In the light of this discussion, we identify desirable features for fisheries simulation models aimed at policy evaluation, and particularly MPA evaluation.
Fish and Fisheries (1467-2960) (Blackwell science), 2005-12 , Vol. 6 , N. 4 , P. 307-349

Droits : 2005 Blackwell Publishing, Inc
http://archimer.ifremer.fr/doc/2005/publication-1031.pdf
DOI:10.1111/j.1467-2979.2005.00199.x
http://archimer.ifremer.fr/doc/00000/1031/

Éditeur(s) : HAL CCSD InTech
Résumé : Available from: http://www.intechopen.com/books/evaporation-condensation-and-heat-transfer/heat-transfer-in-buildings-application-to-solar-air-collector-and-trombe-wall-design
International audience
The aim of this paper is to briefly recall heat transfer modes and explain their integration within a software dedicated to building simulation (CODYRUN). Detailed elements of the validation of this software are presented and two applications are finally discussed. One concerns the modeling of a flat plate air collector and the second focuses on the modeling of Trombe solar walls. In each case, detailed modeling of heat transfer allows precise understanding of thermal and energetic behavior of the studied structures. Recent decades have seen a proliferation of tools for building thermal simulation. These applications cover a wide spectrum from very simplified steady state models to dynamic simulation ones, including computational fluid dynamics modules (Clarke, 2001). These tools are widely available in design offices and engineering firms. They are often used for the design of HVAC systems and still subject to detailed research, particularly with respect to the integration of new fields (specific insulation materials, lighting, pollutants transport, etc.). Available from: http://www.intechopen.com/books/evaporation-condensation-and-heat-transfer/heat-transfer-in-buildings-application-to-solar-air-collector-and-trombe-wall-design
Evaporation, condensation and heat transfer

Droits : info:eu-repo/semantics/OpenAccess
ISBN : 978-953-307-583-9
hal-00767482
https://hal.archives-ouvertes.fr/hal-00767482
https://hal.archives-ouvertes.fr/hal-00767482/document
https://hal.archives-ouvertes.fr/hal-00767482/file/InTecSubmitted.pdf

Éditeur(s) : HAL CCSD
Résumé : 16 p.
National audience
The objective of this paper is to present an approach for experimenting territorial prospective analysis based on spatial modelling. This approach is carried out in the framework of the DESCARTES project which aims at developing a spatial simulation tool to support the design and analysis of different scenarios for land-use allocation in Reunion Island in terms of environmental services. The spatial modelling tool is composed of two complementary applications: (i) the Ocelet modelling language and its land dynamics simulation environment, and (ii) the Margouill@ platform. The first demonstrator, a model of farm land consumption by urbanization, was developed and presented during workshops in order to test the role of the spatial simulation tool in support of a collaborative innovation process among stakeholders, and to foster new research on social learning, spatial simulation of environmental services, and scale change issues.
L'objectif de cet article est de présenter une démarche de construction d'un exercice de prospective territoriale basé sur un outil de modélisation spatiale. Cette démarche est mise en œuvre dans le cadre du projet ANR DESCARTES dont l'objectif est de construire un outil de simulation cartographique pour analyser différents scénarios d'affectation de l'usage des sols à l'Ile de La Réunion, en termes de services environnementaux. La plateforme de simulation cartographique est composée de deux applications complémentaires (i) le langage de modélisation Ocelet et son environnement de simulation de paysages dynamiques, et (ii) la plateforme Margouill@. Le développement puis la présentation, en atelier, d'un premier démonstrateur sur la consommation des terres agricoles par l'urbanisation a permis de tester l'outil cartographique comme support d'un processus d'innovation collective entre les parties prenantes, et d'ouvrir de nouveaux champs de recherche sur l'analyse de la démarche par les apprentissages, la spatialisation et la simulation prospective des services écosystémiques, et la prise en compte du changement d'échelle.
Acte de la Conférence Internationale de Géomatique et d'Analyse Spatiale
Brest, France

cirad-00850243
http://hal.cirad.fr/cirad-00850243
http://hal.cirad.fr/cirad-00850243/document
http://hal.cirad.fr/cirad-00850243/file/SAGEO-Brest2013-version_finale.pdf

Éditeur(s) : HAL CCSD Geological Society of America
Résumé : International audience
Lakes are major depositional systems for which the related depositional processes have long been considered relatively simple. Breaking this statement, this study presents a detailed analysis of deposits in Lake Saint-Jean, the third largest natural lake in Québec. In addition to postglacial deltaic and coastal depositional systems fringing the lake, current-controlled features such as a large subaqueous prograding wedge and three sediment drifts have been identifi ed in its central portion based on two-dimensional (2-D) acoustic high-resolution subbottom profiles. The large subaqueous prograding wedge is a 4-km-long and up to 15-m-thick heterolithic shelf-like construction in the southeastern part of the lake. The three sediment drifts are 0.1–0.5-km-long and 2–5-mthick mud mounds distributed on the lake floor in the central portion of the lake. Diatom analyses and radiocarbon dating show that the development of these current-controlled features occurred during the lacustrine phase, after the disconnection with the postglacial marine Laflamme Gulf at 8.5 cal. k.y. B.P. Depositional facies show evidence of recurrent bottom-current activity. Related deposits alternate with pelagic sedimentation stages characterized by the settling of mud and biogenic accumulations. We investigated the origin of bottom currents using a numerical simulation (SYMPHONIE, an oceanographic model), with the aim of modeling wind-induced lake-scale water circulation. Simulations suggest that the subaqueous prograding wedge and the three sediment drifts result from wind-induced bottom currents generated by storm events having wind speed greater than 10 m s–1. Such strong winds are able to significantly affect sedimentation in the central portion of Lake Saint-Jean. Theresulting wind-induced sedimentary features were integrated into a refi ned lacustrine depositional model that summarizes the evolution of a group of water bodies referred to as “wind-driven water bodies.” This study applies a new tool for lake strata characterization and highlights the potential diffi cultyin differentiating them from marine deposits in the geological record.
ISSN: 0016-7606

insu-01184724
https://hal-insu.archives-ouvertes.fr/insu-01184724
DOI : 10.1130/B31145.1

Éditeur(s) : HAL CCSD
Résumé : International audience
EmailPrintRequest PermissionsThe emergence of new communication means such as online newspapers and exchange and sharing websites allow us to go further in the understanding of diffusion phenomena. Indeed, these public discussion areas are now firmly established in our societies and are known to be strong sensors of both human behaviors and collective feelings. In this paper we focus on diffusion phenomena that occur on Twitter and we propose a set of measures that aims to characterize globally and locally the processes. Our objective is to identify what are the conditions in which a person decides to forward the information. Our measures have been used to study two events occurred in January 2015: the presentation of Microsoft HoloLens, a new augmented reality headset, and the political election in Greece. The results obtained show a strong heterogeneity in the individual behaviours involved in the diffusion process. Our approach has been implemented into a graphical tool which is able to conduct real time analysis on any kind of topics occurring on Twitter.
IEEE International Conference on Research Challenges in Information Science (RCIS)
Athens, Greece

hal-01312382
https://hal.univ-antilles.fr/hal-01312382
DOI : 10.1109/RCIS.2015.7128894

Éditeur(s) : Actes de la 8ème Conférence de l'IIFET (Marrakech, juillet 1996)
Résumé : In the framework of French-Brazil co-operation, the French Institute of research for exploitation of the sea (IFREMER), the State of Bahia and the company Littoral Sul Maricultura have developed a new technique for shrimp farming (Penaeus vannamei) using floating cages. After trials carried out during three years, this technique turns out very interesting from several viewpoints. The growth speed and the survival rate are very good, the negative effects on the environmental quality are weak and local fishermen have proved eager to adopt this technique as a part-time activity. In the same time, a technico-economic analysis, using a computerised simulation tool, as well as a market analysis in the State of Bahia have been carried out in order to assess the feasibility of such a project and to help research and development decisions. Despite low first investment and good biological results, the ex-farm production cost of shrimps weighing 15 g is as high as 4,5 US$ per kilo. This price is due to the low productivity of the labour and to the cost of nets which have a short life-time. It is possible to consider this activity as profitable on the market of Salvador de Bahia. Nevertheless, the question is how to face the international competition, which is particularly strong in the case of tropical shrimps. The conditions allowing enterprises to develop a strategy based on product quality and environmentally friendliness are reviewed. [NOT CONTROLLED OCR]
Dans le cadre de la coopération Franco-Brésilienne, l'IFREMER, l'Etat de Bahia et la société Littoral Sul Maricultura ont développé une nouvelle technique d'élevage de crevettes pénéides (Penaeus vannamei) en utilisant des cages flottantes. Après trois années de mise au point, cette technique s'est avérée intéressante sur plusieurs aspects. La vitesse de croissance et le taux de survie sont très satisfaisants, les effets négatifs sur la qualité du milieu naturel sont faibles et les pêcheurs locaux ont accueilli favorablement cette nouvelle pratique en complément de leur activité traditionnelle. Parallèlement, une analyse technico-économique utilisant un outil de simulation informatique ainsi qu'une analyse du marché de la crevette dans l'état de Bahia ont été conduites afin d'évaluer la faisabilité d'un tel projet et d'orienter les actions de recherche et développement. En dépit d'investissements initiaux plus faibles que dans les élevages en bassins et de bonnes performances zootechniques, le coût de production de crevettes de 15 g atteint 4,7 US$ par kilo. Dans les conditions de marché de l'Etat de Bahia, la rentabilité d'un projet d'élevage de crevettes en cage serait assurée, mais la faible productivité du travail et le coût de remplacement des filets ne permettent pas d'avoir des coûts de production aussi bas que dans les élevages en bassins. C'est pourquoi la question se pose de la possibilité pour ce type de production innovante d'affronter une concurrence internationale très forte comme dans le cas des crevettes tropicales. En particulier, les conditions dans lesquelles les entreprises peuvent développer une stratégie de compétitivité basée sur la qualité de leurs produits et sur le respect de l'environnement sont analysées. [OCR NON CONTRÔLE]

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1996/acte-4071.pdf
http://archimer.ifremer.fr/doc/00000/4071/

Éditeur(s) : Elsevier
Résumé : In order to provide reliable scientific advice and support for fisheries management, it is necessary to evaluate the biological and economic sustainability of complex fisheries, such as multi-species multi-fleet fisheries. Existing policy-screening modelling tools are not fully suitable in this purpose due to either an over-simplified description of population dynamics, or due to the lack of consideration of economic aspects. In this paper, we present a package that enables quantitative bioeconomic assessment of management scenarios. Population dynamics is described through spatially- and seasonally-explicit models. Exploitation dynamics is characterized by several fishing activities with specific spatial and seasonal features, and practiced by several kinds of vessels with specific technical characteristics. Exploitation costs and revenues are considered at several levels: the fishing trip, the fishing unit (vessel and crew), and the vessel owner. The model is generic and can be used for different types of fisheries. A database is attached to the software for the storage and updating of information for each fishery. This includes the specification of model dimensions and of the parameters describing populations and exploitation. Several model assumptions regarding either population or exploitation may be adapted to suit a specific fishery. Both policies and corresponding fishers' response may be interactively specified through JAVA (TM) scripts. This version of ISIS-Fish allows for the calculation of biological and economic consequences of a range of policies, including conventional ones like catch and effort controls, and alternative policies such as marine protected areas. To facilitate policy-screening in a high-dimension parameter space, the software includes features, like interfaces for sensitivity analysis and simulation queues. (C) 2009 Elsevier B.V. All rights reserved.
Ecological Modelling (0304-3800) (Elsevier), 2009-04 , Vol. 220 , N. 7 , P. 1013-1033

Droits : 2009 Elsevier B.V. All rights reserved.
http://archimer.ifremer.fr/doc/2009/publication-6782.pdf
DOI:10.1016/j.ecolmodel.2009.01.007
http://archimer.ifremer.fr/doc/00000/6782/

Éditeur(s) : HAL CCSD Optical Society of America
Résumé : International audience
We present a theoretical simulation of the sarcomeric SHG intensity pattern (SHG-IP) that takes into account myofibrillar misalignment that is experimentally observed in SHG images of proteolysed muscles. The model predicts that myofibrillar displacement results in the conversion from one peak (1P) to two peaks (2P) sarcomeric SHG-IP in agreement with experimental results. This study suggests that sarcomeric SHG-IP is a powerful tool for mapping spatial myofibrillar displacement and its related excitation-contraction disruption that could occur during muscle physiological adaptation and disease.
ISSN: 1094-4087

hal-00820260
https://hal.archives-ouvertes.fr/hal-00820260
https://hal.archives-ouvertes.fr/hal-00820260/document
https://hal.archives-ouvertes.fr/hal-00820260/file/Studysur the_effect-accepted.pdf
DOI : 10.1364/OE.21.011404

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Experimentally Assisted Molecular Modelling (EAMM) is an original approach for predicting the structure of organic micro-crystals and deducing their habit in the presence of various solvents and additives. It is applied here in the case of n-octylamino-nitrobenzoxadiazole (nOA-NBD), a fluorescent compound. This general approach is first of all described and validated by its blind application to three known and closely-related crystals. Then, the whole process is applied to predict the molecular crystal generated by n-octylamino-NBD, including the molecule conformation, its structure (cell parameters, molecular packing, X-ray powder diagrams) and its theoretical plus actual habits in the presence of a solvent (p-xylene) and two additives (acetic acid and n-dodecane). The conformation of the predicted molecule is validated by comparison with two similar molecules embedded in observable crystals. Then, the choice between two proposed structures (with the same energy and two equiprobable packings) is based on the comparison between experimental and re-computed X-ray powder diffraction diagrams, and also on the interpretation of an actual TEM image in the light of the proposed cell parameters. This choice is confirmed by the comparison between the vapour-grown face development (proposed by the BFDH or the attachment energy models) and the actual face development in a pure solvent. Finally, the actual habit deduced from comparing the crystal attachment energy with the adsorption energy of solvent or additive molecules is validated by SEM images of NBD micro-crystals in presence of the solvent alone or in presence of both additives. In conclusion, the EAMM approach appears to be a decisive tool for quickly simulating structural and habit properties of the molecular crystals, accessible or not by experimentation. Thus, a numerical selection of molecules becomes possible in view of deriving organic materials with predetermined properties, such as the fluorescence properties of the compound considered in the present study.
ISSN: 0022-0248

hal-00857894
https://hal.archives-ouvertes.fr/hal-00857894
DOI : 10.1016/j.jcrysgro.2011.07.035

Éditeur(s) : HAL CCSD
Résumé : To understand the effect of inherited lithospheric structures on the continental plates deformation process, we have developed a multi scale model that explicitly takes into account an anisotropic viscosity due to the Crystal Preferred Orientation (CPO) of olivine in the mantle by coupling a viscoplastic self-consistent simulation of the deformation at the polycrystalline aggregate to a 3D Finite Element code. Using this tool, we calculate the mechanical behavior of a continental lithosphere submitted to extension for various initial structures. The first set of experiments investigates the deformation of a plate with a homogeneous initial olivine CPO. Results show that the macroscopic anisotropy is strongly dependent on the initial orientation of the olivine CPO relative to the solicitation and to its evolution. The second set of experiments aims to analyze the deformation of a continental plate containing pre-existing lithospheric scale shear zones. These multi-domain models show that the olivine mechanical anisotropy may induce the reactivation of pre-existing lithospheric scale shear zones in a plate submitted to rifting. In both cases, the results shows that the macroscopic mechanic anisotropy induced by the evolution of olivine CPO in the upper mantle is a key parameter to understand the deformation of the continental plates and to explain the observed reactivation of inherited structure from past tectonics events
Afin de comprendre l'effet des structures préexistantes sur la déformation des plaques continentales, nous avons développé une méthode de modélisation mécanique multi-échelle utilisant une viscosité anisotrope induite par les Orientations Préférentielles du Réseau (OPR) des cristaux d'olivine présents dans le manteau. Cette méthode en couple le calcul viscoplastique autocohérent de la déformation d'un agrégat d'olivine à un code éléments finis 3D. Elle a été utilisée pour le calcul du comportement mécanique d'une plaque continentale soumise à une extension. Une première série d'expériences numériques sur l'extension de plaque lithosphérique présentant des OPR initiales d'olivine homogènes a permis de montrer que l'anisotropie mécanique macroscopique est fortement dépendante de l'orientation initiale de l'OPR. La seconde série de simulations analyse l'extension d'une plaque continentale présentant une zone présentant des OPR d'olivine héritées d'un événement tectonique précédant. Les résultats de ces calculs multi-domaines que l'anisotropie mécanique de l'olivine peut expliquer la réactivation des zones de cisaillement héritées lors du rifting. Les résultats obtenus dans les deux séries de modèles montrent que l'anisotropie mécanique macroscopique induite par l'évolution des OPR d'olivine dans le manteau supérieur est un paramètre clé pour la compréhension de la déformation des plaques continentales et pour expliquer la réactivation observée de structures tectoniques, tels que les grands décrochements, lors des épisodes tectoniques ultérieurs.
https://tel.archives-ouvertes.fr/tel-00369463

tel-00369463
https://tel.archives-ouvertes.fr/tel-00369463
https://tel.archives-ouvertes.fr/tel-00369463/document
https://tel.archives-ouvertes.fr/tel-00369463/file/KnollThese09.pdf

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) : University of Tasmania, Université de Bretagne Occidentale
Résumé : Empirical evidence and the theoretical literature both point to stock sustainability and the protection of marine biodiversity as important fisheries management issues. Decision-support tools are increasingly required to operationalize the ecosystem-based approach to fisheries management. These tools need to integrate (i) ecological and socio-economic drivers of changes in fisheries and ecosystems; (ii) complex dynamics; (iii) deal with various sources of uncertainty; and (iv) incorporate multiple, rather than single objectives. The stochastic co-viability approach addresses the trade-offs associated with balancing ecological, economic and social objectives throughout time, and takes into account the complexity and uncertainty of the dynamic interactions which characterize exploited ecosystems and biodiversity. This thesis proposes an application of this co-viability approach to the sustainable management of mixed fisheries, using two contrasting case studies: the French Bay of Biscay (BoB) demersal mixed fishery and the Australian Northern Prawn Fishery (NPF). Both fisheries entail direct and indirect impacts on mixed species communities while also generating large economic returns. Their sustainability is therefore a major societal concern. A dynamic bio-economic modelling approach is used to capture the key biological and economic processes governing these fisheries, combining age- (BoB) or size- (NPF) structured models of multiple species with recruitment uncertainty, and multiple fleets (BoB) or fishing strategies (NPF). Economic uncertainties relating to input and output prices are also considered. The bioeconomic models are used to investigate how the fisheries can operate within a set of constraints relating to the preservation of Spawning Stock Biomasses (BoB) or Spawning Stock Size Indices (NPF) of a set of key target species, maintenance of the economic profitability of various fleets (BoB) or the fishery as a whole (NPF), and limitation of fishing impacts on the broader biodiversity (NPF), under a range of alternative scenarios and management strategies. Results suggest that under a status quo strategy both fisheries can be considered as biologically sustainable, while socio-economically (and ecologically in the NPF case) at risk. Despite very different management contexts and objectives, viable management strategies suggest a reduction in the number of vessels in both cases. The BoB simulations allow comparison of the trade-offs associated with different allocations of this decrease across fleets. Notably, co-viability management strategies entail a more equitable allocation of effort reductions compared to strategies aiming at maximizing economic yield. In the NPF, species catch diversification strategies are shown to perform well in controlling the levels of economic risk, by contrast with more specialized fishing strategies. Furthermore analyses emphasize the importance to the fishing industry of balancing global economic performance with inter-annual economic variability. Promising future developments based on this research involve the incorporation of a broader set of objectives including social dimensions, as well as the integration of ecological interactions, to better address the needs of ecosystem-based approaches to the sustainable harvesting of marine biodiversity.
L’objectif général de la thèse est de modéliser les principaux processus biologiques et économiques régissant des pêcheries multi-espèces et multi-flottilles afin de proposer des stratégies viables pour la gestion durable de ces pêcheries mixtes, dans un contexte stochastique et multiobjectif. Plus spécifiquement, cette thèse utilise des analyses de co-viabilité stochastique pour étudier les arbitrages entre des objectifs contradictoires de gestion (conservation, et viabilité économique et sociale) des pêcheries mixtes. Deux pêcheries mixtes sont analysées dans cette thèse: la pêcherie française mixte démersale du golfe de Gascogne et la pêcherie crevettière australienne du Nord (NPF). Ces deux pêcheries sont multi-espèces, et utilisent des stratégies multiples de pêche, induisant des impacts directs et indirects sur les écosystèmes. Cette thèse propose une application de la co-viabilité stochastique à ces deux cas, en prenant en compte leur histoire, leur contexte socio-politique et les différences dans les stratégies et objectifs de gestion. Les résultats suggèrent que le status quo peut être considéré comme une stratégie biologiquement durable mais socio économiquement à risque dans les deux pêcheries (ainsi qu’à risque écologique dans le cas de la pêcherie australienne). Les simulations réalisées pour le golfe de Gascogne permettent de comparer les arbitrages associés à différentes réductions de capacités par flottille et de montrer qu’il existe des solutions de gestion permettant la co-viabilité du système (viabilité biologique des différentes espèces considérées et viabilité socio-économique des flottilles) contrairement à des stratégies de gestion mono-spécifiques ou basées sur la maximisation de la rente. Dans la pêcherie crevettière australienne, l’analyse montre que les stratégies de diversification permettent de limiter le risque économique contrairement aux stratégies plus spécialisées.

Droits : UBO, Univ. Tasmania
http://archimer.ifremer.fr/doc/00206/31731/30134.pdf
http://archimer.ifremer.fr/doc/00206/31731/

Éditeur(s) : HAL CCSD
Résumé : International audience
After defining the High Performance Pre- Computing --referred as HPPC-- concept, the aim of the present study is to develop a prototype whether to approve or not the benefits of this concept. Our application case tries to answer the geophysical issue of coastal flooding. This is an example of an alert system based on the HPPC architecture, thus on pre-computed scenarios. The prototype provides the scientists with an ergonomic and on-demand tool allowing the run of scenarios of any implemented numerical models. These runs are available through a web application which submits the corresponding jobs on the remote french public cluster of HPC@LR. In this study we simulate the waves propagation over a Mediterranean grid using the wave model WaveWatch III⃝R . A reference simulation using usual conditions is approximated using the k-NN algorithm over 12, 98 and then 980 pre-computed scenarios. This simple experiment demonstrates how useful the pre-computing of scenarios is for alert systems as far as enough and relevant scenarios are pre-computed. This is the reason why searches continue in each critical points of the HPPC architecture such as the design of experiment, the approximation of the results by meta-models and the research of the closest scenarios in this big data context.
4th International Conference on Knowledge and Systems Engineering
Danang, Vietnam

lirmm-00736797
https://hal-lirmm.ccsd.cnrs.fr/lirmm-00736797
https://hal-lirmm.ccsd.cnrs.fr/lirmm-00736797/document
https://hal-lirmm.ccsd.cnrs.fr/lirmm-00736797/file/PID2396685.pdf
DOI : 10.1109/KSE.2012.36

Éditeur(s) : HAL CCSD De Gruyter
Résumé : COST Action E35 : Fracture mechanics and micromechanics of wood and wood composites with regard to wood machining
The data available in the literature concerning wood cutting forces permits 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 optimise 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 system 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 a focus on potential industrial applications, the emphasis of this review was on the wood peeling process, which is a very demanding special case of wood cutting. Although 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 technological 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-01032121
https://hal.archives-ouvertes.fr/hal-01032121
DOI : 10.1515/HF.2009.014

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In this paper, we present an original and formal framework, the D2SNet model designed to combine both the social network evolution and the diffusion dynamics among individuals. We have conducted experiments on three social networks that show identical characteristics as real social networks. A formal definition of the model is provided and we describe its implementation in a simulation tool. We represent human behaviors and information dissemination strategies by standard and synthetic scheme. In a first step, we study the impact of network growing strategies only and we highlight important parameters such as the evolution speed and mainly the kind of strategies that favour or not the spread. Then we study a more complete evolution strategy that involves link creation and deletion. We provide a deep analysis on the impact of each parameter such as evolution speed, creation and deletion probabilities and dynamic human behaviors on the diffusion amplitude and coverage. Our study gives a novel and useful insight in the diffusion process in a dynamic context.
ISSN: 0747-5632

hal-00786164
https://hal.archives-ouvertes.fr/hal-00786164
DOI : 10.1016/j.chb.2012.06.004