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Fofana, Fatoumata. "Application des méthodes mixtes dans le cadre de la recherche sur les résultats des interventions de santé : utilisation du schéma mixte par conversion de données qualitatives". Nantes, 2015. http://archive.bu.univ-nantes.fr/pollux/show.action?id=a5b2a8a2-e8ab-4305-b823-1eed68edbbc0.
Pełny tekst źródłaThe objective of the thesis was to explore whether mixed methods research, combining qualitative and quantitative methods, can constitute a pertinent approach in outcomes research. A specific methodology was followed: a conversion mixed design, consisting in using quantitative techniques on quantititized data, initially qualitative. The use of a conversion mixed design was illustrated on two qualitative studies, focusing particularly on the saturation question, which is a central notion in qualitative patient-reported outcomes research. The present thesis showed that mixed methods can address the challenges in outcomes research appropriately
Cartron, Emmanuelle. "Quelle place pour la décision médicale partagée en contexte de transplantation rénale ? : une recherche par méthodes mixtes sur l’expérience vécue par les patients". Thesis, Nantes, 2020. http://www.theses.fr/2020NANT1018.
Pełny tekst źródłaAlthough kidney transplantation provides a significant benefit over dialysis, question regarding the eligibility for transplantation, the impact of replacement treatment on their lives, make the mode of renal replacement therapy a difficult decision. Therefore, Health Authority suggests shared decision-making to help patients make timely treatment modality decision. Little is known about how patient perceive their participation in the shared decision-making process. This research aims to explore the experience of patients and the factors that influence them in decision-making situations, as well as to evaluate the impact of this experience on their future. This research is based on a mixed methods research (QUANTI > quali). It combines an interpretive phenomenological analysis and an observational study design to measure decisional conflict perceived by patients on the waiting list and to explore the factors that influence decision regret, quality of life and adherence among transplant recipients. This study reports that the experience of waiting list was identified as a necessary step in their pathway. They experienced as an implicit decision that shapes patients' attitudes towards other decisions and influences their ability to cope with the uncertainty of living with chronic kidney disease. The challenge of considering all stages of shared medical decision making is major in the context of kidney transplantation to support patient participation decision
Tchapnga, Takoudjou Rodrigue. "Méthodes de modélisation et d'optimisation par recherche à voisinages variables pour le problème de collecte et de livraison avec transbordement". Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0052/document.
Pełny tekst źródłaThe thesis is conducted under the ANR project PRODIGE and it is focused on seeking strategies allowing the optimization of transport in general and road freight transport in particular. The transportation problem support for this study is the pickup and delivery problem with transshipment.This problem generalizes several classical transportation problems.Transshipment is used as optimization and flexibility leverage. To study and solve this problem, analyzes are performed along three axes :the first objective concerns the development of an analytical model, more accurately a mathematical model with mixed variables. This model allows providing optimal solution to the decision maker, but has the disadvantage of requiring a time resolution that grows exponentially with the size of the problem. This limitation is overcome by the second line of the study that solves the transportation problem studied by an approximate optimization method while ensuring satisfactory solutions. The method used is a mataheuristic broadly followed the variables neighborhoods research principles. In the third objective, the overall results obtained in the thesis are tested in real transport situation via the PRODIGE project
Brouzes, Chloé. "Quelles stratégies pour améliorer le régime alimentaire de jeunes femmes égyptiennes en milieu urbain ? Analyse des déséquilibres et identification de stratégies nutritionnelles par méthodes mixtes". Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASB002.
Pełny tekst źródłaEgyptian women are a typical yet rarely studied example of population undergoing a nutrition transition, touched by a high prevalence of overweight (88% in urban areas) and iron deficiency (50%). This situation suggests that their dietary intakes, which are so far poorly assessed and not well known, should be rebalanced. Diet modeling is a mathematical tool which helps to identify dietary changes improving nutritional intakes, taking into consideration several parameters of the local food environment. Yet, the acceptability of the nutritional strategies modeled is hardly predictable. This research thesis enabled to quantify the dietary intakes of young Egyptian women living in urban areas and to model strategies to improve nutritional intakes. The acceptability of the “theoretically optimal” solutions was then discussed with the population studied using qualitative surveys. The use of mixed methodologies (quantitative and then qualitative approaches) enabled to analyze in detail the local situation and to identify changes in dietary practices and in the fortified food offer. This approach seems promising to identify realistic and acceptable solutions to contribute solving local nutritional issues
Cadwallader, Jean-Sébastien. "TCA-MG : Prise en charge des patients atteints de troubles des conduites alimentaires par les médecins généralistes français". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS015/document.
Pełny tekst źródłaBackground : People suffering from eating disorders (ED) may have a better prognosis if they benefit from early management for their disease. GPs are often quoted in international guidelines as the main actors of screening and early management of ED patients. Prevalence studies in a primary care setting however find few ED patients and sometimes none. No study in GP has been done in France. Depressive disorders are often related as a comorbidity of ED. Aim: to study the GP role of ED patients management. 1) To evaluate the efficacy of systematic screening of ED patients conducted by GPs on prognosis and recovery. 2) To describe the characteristics of ED patients followed by their GPs and study the temporality between depression management and ED management. 3) To describe GPs and patients' views of the role of GPs management of ED patients. Methods 1)Systematic review according to PRISMA statement 2)Cohort study in a French GP setting of ED patients with analysis of different follow up groups comparing ED patients with depression to ED patients without depression. 3)Qualitative study of ED patients comparing GPs and patients' views selected in the cohort study, with a grounded theory approach and a phenomenological approach, double coding of semi directive interviews. Results : the systematic review found no evidence of efficacy of systematic screening of ED patients by GPs. The literature is too heterogeneous and contains mainly opinion papers in primary care. 1310 patients (out of 350,000) had at least one consultation for ED by GPs in the French database between 1994 and 2007. 80 % were women, mean age of 35.19 years. Only 39 % benefited from a follow up for ED. 67.1 % were taken in charge for the first time. 32.3 % of ED patients had at least one consultation for depression, 62.41 % for the first time. ED patients with depression were older, followed longer for ED then the others. One fifth of patients had at least one prescription of antidepressants during their follow up period, half of them had anxiolytics. Depression management did not precede ED management. In the qualitative study, 24 GPs and 8 patients described the management as difficult and long. The key to a good management depended on trust, with a patient willing to talk about her disease; overcoming shame and denial, and a GP ready to listen, overcoming his helplessness feeling.Discussion : it was the first study about this subject in France, using complementary methods. Management points are to be defined in primary care. Depression and ED are cofactors and should be managed in a global approach. This approach will have to take into account signs found in those two syndroms: low self esteem, negative body image, abuse background, pscyhiatric diseases in family (depression and ED) in first degree relatives
Benhizia, Faten. "OPTIMISATION DU PLAN DE TRANSPORT PAR PLANIFICATION INTEGREE DES RESSOURCES". Thesis, Saint-Etienne, EMSE, 2012. http://www.theses.fr/2012EMSE0668/document.
Pełny tekst źródłaThe planning of railway production at the french national railways (sncf) is currently based on a mainly sequential process in which the design of railway timetabling widely conditioning design planning of railway equipment (rolling stock), then one of the train drivers (driver rosters). this strategy of sequential planning of railway resources massively adopted for practical and scientific reasons (expertise, complexity of the railway system, etc.). however, this strategy generates solutions which can be more expensive and less robust to uncertainties, because decisions taken at any given stage can significantly reduce the overall feasible solutions of the following steps.given this situation and the strong interaction between these heterogeneous and very expensive resources, the thesis deals with the feasibility and inputs of a process where these critical resources could be planned and optimized in an integrated way. the thesis focuses on the feasibility study, prototyping and validation of an integrated approach for planning rolling stocks and drivers, so as to improve the efficiency of the overall transportation plan, increase sncf competitiveness and enhance the quality of its services. we propose a mixed integer linear programming formulation of the rolling stock/ train drivers integrated planning problem. in this mathematical model, each planning sub-problem is formalized and coupling constraints are further introduced to model the interdependencies of these two resources when they are simultaneously used for train production. in this heuristic, the solution of the lagrangian dual and the calculation of feasible solutions are performed by calling two proprietary software modules available at sncf for planning rolling stocks and train drivers. the heuristic is tested experimentally with real data from the ter bretagne region, and several evolutions are introduced in the models and algorithms so as to improve their performances.validation tests on of real data sets at an industrial scale are encouraging and, when compared to a traditional (sequential) approach, show gain of up to 4% for train drivers used
Jamjoom, Bushra. "The determinants of employee engagement on intention to quit in family owned businesses in Saudi Arabia". Electronic Thesis or Diss., Strasbourg, 2018. http://www.theses.fr/2018STRAB015.
Pełny tekst źródłaFamily Owned Businesses (FOB) are at the forefront of the Saudi private sector and account for at least 90 percent, representing 51 percent of the total employment in the nation, hence contributing an income of 232.5 billion Saudi Riyals to the economy. The fortitude of these private enterprises has made family-run businesses one of the major backbones of the Saudi economy. Unfortunately, the Saudi Arabian private sector is observing relatively high labor turnover rates. This, in turn, has negatively impacted business performance, causing loss of knowledge, drops in productivity levels, and reduction of the chance for organizational survival. Therefore, retention and motivation of employees are major concerns for employers and talent management is becoming a key activity. In this context, learning how to engage employees and build loyalty to the organization is likely to be crucial for future success in the Saudi marketplace. The purpose of this Exploratory Sequential Mixed Methods thesis was, first, to identify key determinants of employee engagement within FOBs in Saudi Arabia. Secondly, it intended to test the predictability of the concept of employee engagement quantitatively. Thirdly, it tested the impact of employee engagement on intention to quit for Saudis and non-Saudis in FOBs in Saudi Arabia. The first objective was achieved by semi-structured interviews of full-time employees working for FOBs in Saudi Arabia (N = 28). The second and third objectives were achieved through a survey questionnaire that was developed from twelve pre-tested instruments and was comprised of 84 questions (N = 151). Path analysis, multi-group, and structural equation modeling (SEM) analysis were used along with bootstrapping to examine the variables of interest and mediation effects. Results suggested that a combination of the antecedent variables of this study (i.e., meaningfulness, communication openness, reward, and career growth) predicted employees’ engagement in Saudi FOBs. However, engagement antecedents did not predict engagement for Saudi and non-Saudi employees correspondingly. Meaningfulness, job fit, coworker’s relationship, rewards, and career growth predicted engagement for the Saudi employees. On the other hand, communication openness, and career growth predicted engagement for the non-Saudi/expatriate employeesIn addition, employee engagement had a significant impact on intention to quit for the non-Saudi employees, while it did not have an impact on the Saudi employees in FOBs in Saudi Arabia. Finally, results of the mediation test suggested that employee engagement partially mediated meaningfulness and career growth and intention, and fully mediated communication openness and rewards
Prevost, Guillaume. "Modélisation d'écosystèmes multi-niveaux par des systèmes mixtes". Le Havre, 2005. http://www.theses.fr/2005LEHA0053.
Pełny tekst źródłaWe present in that document a meta-model of aquatic ecosystem which is multi-scale and uses hybrid approaches. Ecosystems are complex systems. Therefore, the model is made to give a performant description of multi-level interactions occuring in them. Thus, we propose a multi-scale and multi-level meta-model designed as an holarchy and embodying different approaches (equationnal, individual-based,. . . . ). Moreover, we present an ontology of the meta-model which help users understand and use that one. The methodology to apply the meta-model on a concrete problem using the ontology is shown. Finally, a plateform allowing using to compute their model as far as those ones respect the meta-model assumptions is described. Then, we introduce technics to detect, reify and handle emerging systems during the simulations. Those technics are based on the analysis of the interaction network of predator-preys simulation
Kermad, Chafik. "Segmentation d'image: recherche d'une mise en oeuvre automatique par coopération de méthodes". Phd thesis, Université Rennes 1, 1997. http://tel.archives-ouvertes.fr/tel-00008781.
Pełny tekst źródłaLaffly, Dominique. "Évolutions et potentiels de l'espace comtois : recherche de méthodes par la télédétection". Besançon, 1995. http://www.theses.fr/1995BESA1003.
Pełny tekst źródłaRemote sensing is a privilegied tool of the earth observation with the image's coverage, repetitivity of datas acquisition, the pixel's spectral and spatial resolution. We present in a first time an abstract of the most important radiometric and geometric operations with originals datas. After that, we developpe an example of comparison between may 1975 (mss datas) and july 1988 (tm datas) on the franche-comte area. Two ways are selected. The first one consists of a global observation of the evolution with the help of hierarchical step of spatial agregation. The second one concerns local landscpte modification and we propose a new method fonded on spatial resampling of datas and multiple factorial correspondances analysis. In a third part, we propose an other approach of remote sensing with an ecological problem about the area of "grand tetras" (tetrao urogallus). We developpe a texture filter to recognise the areas on a spot panchromatic image. The analyse needs more information and we use at the end a gis to combine datas about vegetable's physionomy and composition (spot p and xs), topographic model and a representation of human's pressure with an empiric model of noise diffusion
Kassou, Ismaïl. "Amélioration d'ordonnancements par des méthodes de voisinage". Rouen, 1992. http://www.theses.fr/1992ROUES025.
Pełny tekst źródłaZaourar, Sofia. "Optimisation convexe non-différentiable et méthodes de décomposition en recherche opérationnelle". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENM099.
Pełny tekst źródłaDecomposition methods are an application of the divide and conquer principle to large-scale optimization. Their idea is to decompose a given optimization problem into a sequence of easier subproblems. Although successful for many applications, these methods still present challenges. In this thesis, we propose methodological and algorithmic improvements of decomposition methods and illustrate them on several operations research problems. Our approach heavily relies on convex analysis and nonsmooth optimization. In constraint decomposition (or Lagrangian relaxation) applied to short-term electricity generation management, even the subproblems are too difficult to solve exactly. When solved approximately though, the obtained prices show an unstable noisy behaviour. We present a simple way to improve the structure of the prices by penalizing their noisy behaviour, in particular using a total variation regularization. We illustrate the consistency of our regularization on real-life problems from EDF. We then consider variable decomposition (or Benders decomposition), that can have a very slow convergence. With a nonsmooth optimization point of view on this method, we address the instability of Benders cutting-planes algorithm. We present an algorithmic stabilization inspired by bundle methods for convex optimization. The acceleration provided by this stabilization is illustrated on network design andhub location problems. We also study more general convex nonsmooth problems whose objective function is expensive to evaluate. This situation typically arises in decomposition methods. We show that it often exists extra information about the problem, cheap but with unknown accuracy, that is not used by the algorithms. We propose a way to incorporate this coarseinformation into classical nonsmooth optimization algorithms and apply it successfully to two-stage stochastic problems.Finally, we introduce a decomposition strategy for the machine reassignment problem. This decomposition leads to a new variant of vector bin packing problems, where the bins have variable sizes. We propose fast and efficient heuristics for this problem that improve on state of the art results of vector bin packing problems. An adaptation of these heuristics is also able to generate feasible solutions for Google instances of the machine reassignment problem
Genty, Éric. "Synthèse par méthodes conventionnelles ou non d'oxydes mixtes par voie hydrotalcite : Application pour l'oxydation des COV et du CO". Thesis, Littoral, 2014. http://www.theses.fr/2014DUNK0412.
Pełny tekst źródłaCatalytic oxidation is one of the promising technologies to reduce VOC emissions. The objective of this work was to develop active, selective and stable catalyst for the destruction of VOC. In order to find an alternative to the use of noble metals based catalysts, this research has been focused on the synthesis of materials based on transition metal oxides. The various mixed oxides were characterized by different physico-chemical techniques including XRD, Thermal Analysis, H2-TPR, TEM, XPS...Initially, a study on the preparation of mixed oxides derived from hydrotalcite-like precursors was conducted. Thus, it was shown that the mixed oxide containing cobalt and aluminum exhibited interesting for catalytic activity for the toluene aznd carbon monoxide total oxidation. To improve this mixed oxide, a study of the influence of non-conventional methods for the preparation of the precursor was performed. The microwave and ultrasound have been used in these syntheses. The various mixed oxides thus prepared were tested in the oxidation reactions of CO and toluene. In this application, a beneficial effectvof the use of microwaves in the synthesis was observed. Thirdly, a study of the incorporation of cerium in the hydrotalcite structure was conducted. Mixed oxides of CoAlCe show interest for the total oxidation of toluene catalytic activity. Moreover, a relationship between the reductibility and the catalytic activity has been demonstrated. A comparison of the best catalysts of this study and catalysts of noble metals business was discussed. The kinetic study of the complete oxidation of toluene showed that in the case of mixed oxides CoAlCe and CoAl, a mechanism of March Van Krevelen type described the reaction
Giraud, Moreau Laurence. "Optimisation des systèmes mécaniques : couplage de méthodes déterministes et évolutionnaires par les problèmes en variables mixtes". Troyes, 1999. http://www.theses.fr/1999TROY0006.
Pełny tekst źródłaBen, mhenni Ramzi. "Méthodes de programmation en nombres mixtes pour l'optimisation parcimonieuse en traitement du signal". Thesis, Ecole centrale de Nantes, 2020. http://www.theses.fr/2020ECDN0008.
Pełny tekst źródłaSparse approximation aims to fit a linear model in a least-squares sense, with a small number of non-zero components (the L0 “norm”). Due to its combinatorial nature, it is often addressed by suboptimal methods. It was recently shown, however, that exact resolution could be performed through a mixed integer program(MIP) reformulation solved by a generic solver, implementing branch-and-bound techniques. This thesis addresses the L0-norm sparse approximation problem with tailored branch-andbound resolution methods, exploiting the mathematical structures of the problem. First, we show that each node evaluation amounts to solving an L1-norm problem, for which we propose dedicated methods. Then, we build an efficient exploration strategy exploiting the sparsity of the solution, by activating first the non-zero variables in the tree search. The proposed method outperforms the CPLEX solver, reducing the computation time and making it possible to address larger problems. In a second part of the thesis, we propose and study the MIP reformulations of the spectral unmixing problem with L0-norm sparsity more advanced structured sparsity constraints, which are usually addressed through relaxations in the literature. We show that, for problems with limited complexity (highly sparse solutions, good signal-to-noise ratio), such constraints can be accounted for exactly and improve the estimation quality over standard approaches
Loiseau, Yannick. "Recherche flexible d'information par filtrage flou qualitatif". Toulouse 3, 2004. http://www.theses.fr/2004TOU30263.
Pełny tekst źródłaWith the raise of electronic data, efficient information retrieval systems become necessary. To represent these information and the user needs, a better agreement between human and computer is needed. Our approach uses the fuzzy pattern matching to define a linguistic data representation, based on linked vague terms classes to model relations and ambiguity in language, defining a possibilistic concepts ontology. By representing user needs likewise, we match them with the information, and exploit links to evaluate vague searches with more relevant results. Lastly, all needs are kept in the final evaluation to discriminate documents using methods from multicriteria techniques. We first present several database and information retrieval aspects, and their integration with fuzzy techniques. The theoretic model of this approach is exposed, and applied to these two fields. Lastly, we illustrate the system and evaluate its real performances and advantages
Da, Rugna Jérôme. "De l'usage des méthodes bas niveau pour la recherche d'image par le contenu". Phd thesis, Université Jean Monnet - Saint-Etienne, 2004. http://tel.archives-ouvertes.fr/tel-00070811.
Pełny tekst źródłal'apport des méthodes bas niveau.
Après avoir discuté des différentes approches existantes, nous rappelons le fossé sémantique
entre les attentes de l'utilisateur et ce que proposent réellement les systèmes de recherche. La
plupart de ceux-ci reposent sur une étape préalable de segmentation dont la validité et la robustesse
se doivent d'être étudiées. Nous proposons alors un protocole d'évaluation objective et un
exemple concret de mise en oeuvre. L'originalité consiste à ne pas comparer une segmentation à
une référence théorique mais à juger objectivement sa stabilité.
La troisième partie de ce document introduit trois contributions ponctuelles susceptibles
d'améliorer la chaîne de recherche. Dans un premier temps, un détecteur de flou permet d'extraire
une méta-information portée par l'image, les zones nettes a priori de focalisation. Ensuite
nous exposons un descripteur basé sur l'extraction de régions émergentes sur le seul critère couleur.
Cette extraction, conjuguée avec des distances adaptées, peut permettre par exemple un
pré-filtrage couleur en amont de la phase de recherche de similarité proprement dite. Finalement,
nous introduisons brièvement une algèbre d'histogrammes pour exploiter au mieux l'information
contenue dans ce type de descripteurs, via un langage de requêtes spécifique.
Da, Rugna Jérôme. "De l'usage des méthodes bas niveau pour la recherche d'images par le contenu". Saint-Etienne, 2004. http://www.theses.fr/2004STET4015.
Pełny tekst źródłaThe matter of this work is content based image retrievaland more precisely the contribution of the low level methods. After having discussed the various existing approaches, we recall the semantic gap between the user expectations and what really the systems of research propose. Most of these approaches rely on a preliminary step of segmentation whose validity and robustness must be studied. Then we propose a protocol of evaluation and a practical example of benchmarks. The originality consists in not comparing a segmentation with a theoretical reference but judging its stability objectively. The third part of this document introduces three specific contributions likely to improve the chain of research. Initially, a detector of blur allows to extract a meta-data carried by the image: the unblur regions, a priori of focusing. Secondly, we expose a descriptor based on the extraction of emergent areas using only the color criteria. This process, combined with adapted distances, may allow for example a color pre-filtering before the step of similarity research. Finally, we briefly introduce an algebra of histograms able as well as possible to exploit the information contained in this type of descriptors, via a specific query language
Dupin, Cecile. "La recherche infirmière en France : approche sociologique et épistémologique". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066128.
Pełny tekst źródłaNursing research and education recently changed in France. In our country, the nursing discipline is currently transforming toward an academic institutionalisation. European development of nursing research is heterogeneous, but the paths of progress seem similar if four sequential stages. Nursing research is characterized by its diversity. However, French nurses implement research projects, in a relative seclusion. In the current professional, disciplinary and intellectual French nursing context, how can nursing research integrate both the international arena and develop its own unique programme? This thesis further aspires to highlight French nurses? scientific values and provide guidelines for nursing research and education in France. The research programme Thot, a multi-method programme, was launched in 2010 to study the development of French nursing research capacity. Thot 1 study was a descriptive cross-sectional analysis of the Hospital Nursing Research Programme 2010 and 2011 scientific activity. Thot 2 study was an ethnography of nursing research practices, combined with clinical practice. Thot 3 was a phenomenographic study of research concepts acquired during a doctoral apprenticeship in France and Sweden. Seven values were derived from the integration of the results of the three studies: reflexivity, dedicated education, coherence, diversity, confidence, transmission and transformation. We hope that this programme, deployed and implemented concurrently to one of the stage of development of nursing in France, will participate in the future integration of the values of French nurses as scientific values
Rigal, Jean-François. "Analyse et modélisation des systèmes mécaniques en conception assistée par ordinateur". Lyon, INSA, 1989. http://www.theses.fr/1989ISAL0095.
Pełny tekst źródłaHabchi, Baninia. "Mise en évidence des perturbations métaboliques liées à l’exposition aux toxiques présents dans l’environnement ou l’aliment par spectrométrie de masse à ultra haute résolution FTMS combinée avec des outils chimiométriques". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLA032.
Pełny tekst źródłaPublic health monitoring involves evaluation of population exposure to environmental toxicants which can have an impact on their health. To do this, robust and high-throughput approaches are required to perform large scale analyses. Global approaches such as metabolomics which aim to reveal metabolic changes due to environmental stress or diseases seem to be the most appropriate approach. This multidisciplinary approach requires powerful analytical techniques such as mass spectrometry (MS) associated with statistical and chemometric data processing. It allows to detect general metabolic disruptions induced by a given physiological or pathological conditions. The studied samples can be injected either directly by the DIMS technique (direct introduction mass spectrometry) or following a chromatographic separation using GC/MS or LC/MS (gas or liquid chromatography / mass spectrometry). The DIMS approach leads to a significant reduction in analysis time, down to only a few minutes (usually less than 3 min). Additionally, in combination with Fourier transform mass spectrometers (DIFTMS), it provides very high mass resolving power and accurate mass measurements, as well as a wide dynamic range resulting in improved efficiency. Nevertheless, the DI-FTMS approach generates complex data containing several thousands of peaks. Processing such large data sets requires the development of dedicated chemometric and statistical tools to detect exposure biomarkers. Therefore, the objective of my work was to develop a rapid, highthroughput workflow, including the development of chemometric tools, in order to highlight metabolomic perturbations induced by exposure to toxicants. The first part of this work concerns the study of farmers professionally exposed to two pesticides. The DIMS approach was performed on an Orbitrap instrument and a new chemometric tool called Independent Component - Discriminant Analysis (IC-DA) was developed for supervised analysis of the DIMS data. The developed methodology was then applied to a larger number of samples corresponding to five types of exposure. In this later study, two analytical approaches DIMS and LC/MS were examined in order to validate the DIMS approach as well as the developed chemometric data analysis tool. In a second part of this work, the DIMS approach was applied to an instrument of higher performances, the FT-ICR (Fourier transform-ion cyclotron resonance) equipped with a dynamically harmonized cell in order to improve the quality of the DIMS data. A first study explored the effects of exposure of rats to different concentrations of pesticides. In a second step, the procedure was applied to a large number of samples (of approximately 500 individuals) to test the robustness of the approach. All this work demonstrated the feasibility and effectiveness of our high-throughput metabolomic approach combining the direct introduction (DIMS), the very high resolution detection and the chemometric tools. This approach could be very promising to perform large scale metabolic phenotyping such as in epidemiological studies
Lenica, Anneli. "Méthodes d'accès décentralisées pour la recherche par le contenu dans les environnements distribués dynamiques". Paris 6, 2010. http://www.theses.fr/2010PA066068.
Pełny tekst źródłaLalande-Markon, Marie-Pierre. "Perceptions et réponses du public aux incertitudes associées aux risques de santé publique: Une investigation par méthodes mixtes". Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20258.
Pełny tekst źródłaAit, ou ammi Ali. "Sur l'approximation des équations de Navier-Stokes bidimensionnelles incompressibles par des méthode multi-niveaux de type Galerkin non linéaire : cas des élements finis mixtes". Ecully, Ecole centrale de Lyon, 1994. http://www.theses.fr/1994ECDL0008.
Pełny tekst źródłaMroué, Ali. "Modélisation et simulation d’opérateur humain dans une tâche de recherche d’information par navigation". Aix-Marseille 3, 2009. http://www.theses.fr/2009AIX30041.
Pełny tekst źródłaThrough the development of tools for modeling and simulation of human operators in computerized tasks, we were interested in the analysis of paths borrowed the users in Web sites. A first module has been developed which, based on log files collected by the Web server, extracts sessions of users. A second module exploits the results of the first one in order to group the similar sessions into classes. We deduct from these classes behavior models. These latter come to enrich theoretical models of information retrieval (IR) in hypermedia tasks. We reach then a behavior model of an Internet user in an IR by navigation task. The crossing of the two approaches allows us to increase the realism of the elaborated models. At first expressed in GOMSL, they are then specified in DEVS allowing their simulations and tests to verify our assumptions about user activity. Cognitive criteria are also taken into account to cover the factors influencing the decision. The experiments made on many websites showed satisfying results at once on the extraction of the classes and the behavior models. This suggests the use of such simulator for the evaluation of the information accessibility according to a goal or to certain knowledge. Beyond this case, the models and the developed platform should allow studies and developments on other software environments and on other tasks
Berrada, Mohamed. "Une approche variationnelle de l'inversion : de la recherche locale à la recherche globale par carte topologique : application en inversion géoacoustique". Paris 6, 2008. http://www.theses.fr/2008PA066016.
Pełny tekst źródłaFerecatu, Marin. "Recherche d'images par retour de pertinence actif utilisant des descripteurs visuels et textuels". Versailles-St Quentin en Yvelines, 2005. http://www.theses.fr/2005VERS0001.
Pełny tekst źródłaIn this thesis we explore a number of issues related to interactive querying of image databases, using both the description of the visual appearance and keyword annotations. We start by introducing the weighted color histograms, that intimately integrate color, texture and shape, and we validate their quality on multiple ground truth databases. Then, we propose several improvements for the SVM-based relevance feedback approach: first, we put forward an improved active learning selection strategy, based on a reduction of the redundancy between the images selected at every feedback round and second, we propose the use of specific kernel functions, such as the triangular kernel, that allow to obtain insensitivity to changes in the scale of the data, while keeping performance at a very good level. Finally, for image databases having keyword annotations associated with images, we propose a new keyword-based feature vector that makes use of an external ontology (WordNet) to induce a semantic generalization of the concepts corresponding to keywords. When used in combination with the visual signatures, our new feature vector can improve significantly the quality of the returned results both in query by visual example situation and with relevance feedback
Sinoimeri, Artan. "Contribution à l'étude du comportement mécanique des étoffes par méthodes énergétiques : cas de l'armure toile". Mulhouse, 1993. http://www.theses.fr/1993MULH0299.
Pełny tekst źródłaOudin, Fabienne. "Schémas volumes finis pour problèmes elliptiques : analyse a priori et a posteriori par éléments finis mixtes, méthode de décomposition de domaines". Lyon 1, 1995. http://www.theses.fr/1995LYO10303.
Pełny tekst źródłaAuclair, Adrien. "Méthodes rapides pour la recherche des plus proches voisins SIFT : application à la recherche d'images et contributions à la reconstruction 3D multi-vues". Paris 5, 2009. http://www.theses.fr/2009PA05S012.
Pełny tekst źródłaIn the first part of this thesis, we are concerned by the nearest neighbour problem, applied on local image descriptors. We restricted ourselves to the SIFT descriptors because of its efficiency. The application of this work is the retrieval of similar images in large databases. First, we compare performances of linear search, on CPU and on GPU (graphic processors), and also when using partial distances. Then, we propose new hash functions t solve the approximate nearest neighbours problem. The hash functions we propose are based on a selection of a few distinctive dimensions per point. For the application of near duplicate retrieval, our algorithm is more efficient than state-of-the-art algorithms. Tested on a database containing 500. 000 images, it finds similar images in less than 300ms. Eventually, we show that it fits very simply within a Bag-Of-Features approach, and it retrieves mor images than kmeans based vocabularies. In a second part, we propose several results on the problem of multi-view 3D reconstruction. We first propose a robust method to obtain the 3D reconstruction of a car from a video sequence. Our system uses the hypothesis that the car is in linear translation in order to fit a point cloud with polynomial surfaces. Then, we propose an algorithm, not dedicated to cars, that uses SIFT descriptors to obtain the 3D surface from images of an object. The descriptors correspondences are searched between input images and virtual images of the temporary object. With this method, the reconstructed surface converges to the true surface object
Grave, Xavier. "Etude de méthodes pour la recherche avec le détecteur VIRGO d'ondes gravitationnelles émises par des étoiles à neutrons". Phd thesis, Université Paris Sud - Paris XI, 1997. http://tel.archives-ouvertes.fr/tel-00003045.
Pełny tekst źródłaDans une première partie, l'étoile à neutrons et son émission d'ondes gravitationnelles, sont présentées. Ensuite le détecteur, les principales sources de bruits, ainsi que la solution adoptée pour l'étalonnage sont décrits.
Puis dans une seconde partie la modélisation des effets dus aux mouvements de la terre (effet Doppler, modulation d'amplitude) est décrite. Leurs conséquences sur le rapport signal sur bruit sont déterminées.
Les deux derniers chapitres sont consacrés aux algorithmes de recherche de signaux périodiques. Tout d'abord le cas où la position de la source est connue est présenté. Le ralentissement de la rotation de la source et la correction de cet effet sont décrits. La correction de l'effet Doppler est aussi détaillée. De même, le problème de la gestion du gigantesque flot de données à traiter est abordé, et une solution y est apportée. Finalement la difficulté de recherche multidirectionnelle est présentée. Des prototypes d'algorithmes hiérarchiques sont aussi évalués.
Barbotteau, Yves. "Recherche des modifications de caractéristiques dans des biomatériaux en verre bioactif par des méthodes nucléaires et physico-chimiques". Phd thesis, Clermont-Ferrand 2, 2002. http://www.theses.fr/2002CLF21360.
Pełny tekst źródłaPhilibert, Aurore. "Méthodes de méta-analyse pour l’estimation des émissions de N2O par les sols agricoles". Thesis, Paris, AgroParisTech, 2012. http://www.theses.fr/2012AGPT0072/document.
Pełny tekst źródłaThe term meta-analysis refers to the statistical analysis of a large set of results coming from individual studies about the same topic. This approach is increasingly used in various areas, including agronomy. In this domain however, a bibliographic review conducted by this thesis, showed that meta-analyses were not always of good quality. Meta-analyses in agronomy very seldom study the robustness of their findings relative to data quality and statistical methods.The objective of this thesis is to demonstrate and illustrate the importance of sensitivity analysis in the context of meta-analysis and as an example this is based on the estimation of N2O emissions from agricultural soils. The estimation of emissions of nitrous oxide (N2O) is made at the worldwide level by the Intergovernmental Panel on Climate Change (IPCC). N2O is a potent greenhouse gas with a global warming power 298 times greater than the one of CO2 over a 100 year period. The key characteristics of N2O emissions are a significant spatial and time variability. Two databases are used for this work: the database of Rochette and Janzen (2005) and the one of Stehfest and Bouwman (2006). They collect numerous worldwide N2O emissions measurements from published studies and have played a significant role in the estimation of N2O emissions produced by the IPCC. The results show the value of random effects models in order to estimate N2O emissions from agricultural soils. They are well suited to the structure of the data (repeated observations on the same site for different doses of fertilizers, with several sites considered). They allow to differentiate the inter-site and intra-site variability and to estimate the effect of the rate of nitrogen fertilize on the N2O emissions. In this paper, the analysis of the sensitivity of the estimations to the shape of the relationship "Emission of N2O / N fertilizer dose" has shown that an exponential relationship would be the most appropriate. Therefore it would be appropriate to replace the constant emission factor of the IPCC (1% emission whatever the dose of nitrogen fertilizer) by a variable factor which would increase with the dose. On the other hand we did not identify significant differences between frequentist and Bayesian inference methods. Two approaches have been proposed to include environmental variables and cropping practices in the estimates of N2O. The first one using the Random Forest method allows managing missing data and provides the best N2O emissions predictions. The other one, based on random effects models allow to take into account these explanatory variables via one or several measurements of N2O. They allow predicting N2O emissions for non-tested doses in unfertilized farmer's field. However their results are sensitive to the experimental design used locally to measure N2O emissions
Guez, Judith. "Illusions entre le réel et le virtuel (IRV) comme nouvelles formes artistiques : présence et émerveillement". Thesis, Paris 8, 2015. http://www.theses.fr/2015PA080109/document.
Pełny tekst źródłaIllusions surprise, amuse and amaze. If among the aesthetic intentions of the creator is the objective of raising questions in the spectator's mind about her own perception of everyday reality, then illusions can become an essential asset of artistic creation. Furthermore, we observe that the field of virtual and mixed reality, with its digital technologies of immersion and interaction, provides new possibilities to "transport" the spectator in unusual worlds, imagined by the artists. Thus, from my double interest in illusions and virtual and mixed reality, I was led to develop a research-creation on new artistic forms of illusion. Inspired from Edgard Morin's method of complexity, I theoretically and practically explored the space of illusions between the real and the virtual (IRV), to identify and create these new art forms emerging from the synergy of the relationship between the spectator, the artistic work and the artist. I composed my own palette for the creation of IRV, which covers the three borders: the one between the real and the virtual, the one between the virtual ant the illusion, and finally the one between the virtual and the illusion. I thus clarified my artistic approach emerging from this research: aiming at the development of experiments nesting several levels of illusions of reality, with the help of real and virtual apparatuses, and striving to explore illusions unique to the virtual, to achieve deeper illusion and presence in the experience offered to the spectator. I can then go closer to what I call the survirtuality, the virtual being a wonderful way to imagine, to dream worlds of nested illusions
Vincent, Christian. "Méthodes de gradient conjugué préconditionné et techniques multigrilles pour la résolution du problème de stokes par éléments finis mixtes Q1-PO stabilisés : applications". Aix-Marseille 1, 1991. http://www.theses.fr/1991AIX11343.
Pełny tekst źródłaOllier, Edouard. "Sélection de modèles statistiques par méthodes de vraisemblance pénalisée pour l'étude de données complexes". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEN097.
Pełny tekst źródłaThis thesis is mainly devoted to the development of penalized maximum likelihood methods for the study of complex data.A first work deals with the selection of generalized linear models in the framework of stratified data, characterized by the measurement of observations as well as covariates within different groups (or strata). The purpose of the analysis is then to determine which covariates influence in a global way (whatever the stratum) the observations but also to evaluate the heterogeneity of this effect across the strata.Secondly, we are interested in the selection of nonlinear mixed effects models used in the analysis of longitudinal data. In a first work, we describe a SAEM-type algorithm in which the penalty is taken into account during step M by solving a penalized regression problem at each iteration. In a second work, inspired by proximal gradient algorithms, we simplify the M step of the penalized SAEM algorithm previously described by performing only one proximal gradient iteration at each iteration. This algorithm, called Stochastic Approximation Proximal Gradient Algorithm (SAPG), corresponds to a proximal gradient algorithm in which the gradient of the likelihood is approximated by a stochastic approximation technique.Finally, we present two statistical modeling works realized during this thesis
Schmitt, Bénédicte. "Conception de techniques d'interaction mixtes dédiées aux environnements virtuels hétérogènes : approche centrée sur les usages et guidée par les modèles". Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2460/.
Pełny tekst źródła3D environments are increasingly present in our life (games, cultural situation, or professional applications). At the same time, new interaction techniques continuously appear to improve the user interaction with systems. Evaluations are usually proposed to assess the implementation of an interaction technique in a specific type of environment for elementary tasks (e. G. Selection or navigation) to determine the consistency of the technique in terms of performance and satisfaction. Our works aim at defining an evaluation method in 3D environment that is based on the standard ISO 9241-9. To answer to issues of linked multi-views systems, we adapt the standard ISO 9241-9 to a heterogeneous environment that mixes 2D and 3D
Charveriat, Mathieu. "Développement de modèles cellulaires infectés par des prions humains et recherche de molécules thérapeutiques". Paris 6, 2009. http://www.theses.fr/2009PA066145.
Pełny tekst źródłaVieilly, Claude. "Etude de quelques méthodes de recherche de Legionella dans l'environnement : application à la surveillance de réseaux de distribution d'eau". Lyon 1, 1985. http://www.theses.fr/1985LYO11684.
Pełny tekst źródłaDib, Mohammad. "Tabu-NG : hybridation de programmation par contraintes et recherche locale pour la résolution de CSP". Phd thesis, Université de Technologie de Belfort-Montbeliard, 2010. http://tel.archives-ouvertes.fr/tel-00607503.
Pełny tekst źródłaEl, Khaoulani Rachid. "Prédiction fiable de l'endommagement ductile par la méthode des éléments finis mixtes : endommagement non local et adaptation de maillage". Phd thesis, École Nationale Supérieure des Mines de Paris, 2010. http://pastel.archives-ouvertes.fr/pastel-00566805.
Pełny tekst źródłaTandalam, Aswinikumar Anuragini. "Bridging cultural discontinuities in global virtual teams : role of cultural intelligence". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLE008.
Pełny tekst źródłaRecent advances in information and communication technologies (ICTs) have been instrumental in transforming many of the traditional work practices and organizational structures. Global virtual teams (GVTs) are one such example. Prior research on GVT identifies ‘cultural discontinuity’ as a salient boundary that needs to be bridged for better performance. Grounding the study in organizational discontinuity theory (ODT), in this research, we propose cultural intelligence (CQ) as one of the modalities through which cultural discontinuities in GVTs could possibly be bridged. Situating the discussion, in transactional model of stress and coping (TMSC), we develop a CQ nomological network describing the inter-relationships and mechanisms through which different CQ dimensions influence GVT performance. Further, leveraging compensatory adaptation theory (CAT) the significant role of structural adaptation (role structure adaptation) is hypothesized, in addition to behavioral adaptation (CQ behavior), in the proposed CQ framework for the GVT context. For testing the theorized conceptual model, the study uses a sequential mixed methods research design comprising a quantitative study followed by a qualitative The integrated findings enable us to propose a 'substantive theory of CQ for GVT performance' thereby making significant contributions to both theory and practice
Robin, Tiphaine. "Mise au point de méthodes de recherche large de xénobiotiques par chromatographie liquide couplée à la spectrométrie de masse en tandem". Thesis, Limoges, 2020. http://www.theses.fr/2020LIMO0052.
Pełny tekst źródłaScreening methods for compounds of interest in clinical toxicology have been historically employed as first-line analysis to either confirm or exclude the hypothesis of drug overdose, or poisoning with a toxicant. After identification using a screening method, quantification using specific methods is often necessary in a second time to assess the severity of intoxication. This obviously increases the turnaround time and has an impact on patient care. With regards to the rapidity needed to report results in clinical toxicology, sample extraction may be a limiting step. There is no universal extraction procedure for human samples prior to screening analysis Our goal were to developed screening procedures using a programmable liquid handler (CLAM-2000; Shimadzu®) directly coupled to a liquid chromatography - tandem mass spectrometry (LC-MS 8060; Shimadzu®).Libraries with spectral and chromatographic parameters were built for about 1300 compounds selected based on their relevance to, and occurrence in, clinical toxicology. Using these libraries, screening methods were developed using different acquisition modes.Two different extraction procedures were developed: one using QuEChERS salts, another using the CLAM-2000.Each approach was validated according to the ISO 15189 requirements and was applied to real patient samples. The different screening methods yielded high confidence in compound detection and should be useful in core labs facing clinical toxicology situations where rapid and reliable results are needed
Nasser, Hanan. "Méthode de résolution du M4-5n par éléments finis mixtes pour l’analyse des chaussées avec discontinuités". Thesis, Ecole centrale de Nantes, 2016. http://www.theses.fr/2016ECDN0005/document.
Pełny tekst źródłaPavements are multilayer structures which undergo cracking distress due to traffic and climatic factors. It is important nowadays to be able to model the mechanical response of such damaged pavements in order to assess their residual lifetime or to design reinforcement solutions. In this context, the present thesis aims at developing a numerical tool dedicated to the analysis of pavements incorporating cracks or discontinuities. In the developed approach, the pavement structure is modeled as a stacking of “plate” elements of typeM4-5n (Multi-Particle Models of Multilayer Materials) which considers 5n equilibrium equations. A reference quick 2D calculation tool for cracked pavements and a general solving of M4-5n by the mixed Finite Element (FE) method was developed. The starting point for this method is the derivation for M4-5n of the variational principle based on the complementary energy theorem whose condition of statically admissible stress is taken into account using Lagrange multipliers. Discretization of the generalized stresses involves interpolation spaces, proposed to avoid ill-conditioned system of algebraic equations after discretization and to insure stability of the solution. The developed method is implemented in a FreeFem++ script. In this method, the initial 3D problem can be handled through FE simulations in 2D and finite values of the generalized stresses are obtained at crack and interlayer debonding locations. The developed numerical tool was validated and applied to the study of the mechanical response of a structure with cracks representative of a pavement tested underfull-scale conditions during an accelerated fatigue test performed at IFSTTAR
Philibert, Aurore. "Méthodes de méta-analyse pour l'estimation des émissions de N2O par les sols agricoles". Phd thesis, AgroParisTech, 2012. http://pastel.archives-ouvertes.fr/pastel-00913760.
Pełny tekst źródłaAl, Kharboutly Mira. "Résolution d’un problème quadratique non convexe avec contraintes mixtes par les techniques de l’optimisation D.C". Thesis, Normandie, 2018. http://www.theses.fr/2018NORMLH06/document.
Pełny tekst źródłaOur objective in this work is to solve a binary quadratic problem under mixed constraints by the techniques of DC optimization. As DC optimization has proved its efficiency to solve large-scale problems in different domains, we decided to apply this optimization approach to solve this problem. The most important part of D.C. optimization is the choice of an adequate decomposition that facilitates determination and speeds convergence of two constructed suites where the first converges to the optimal solution of the primal problem and the second converges to the optimal solution of the dual problem. In this work, we propose two efficient decompositions and simple to manipulate. The application of the DC Algorithm (DCA) leads us to solve at each iteration a convex quadratic problem with mixed, linear and quadratic constraints. For it, we must find an efficient and fast method to solve this last problem at each iteration. To do this, we apply three different methods: the Newton method, the semidefinite programing and interior point method. We present the comparative numerical results on the same benchmarks of these three approaches to justify our choice of the fastest method to effectively solve this problem
Van, Nifterik Laurent. "Développement de méthodes analytiques adaptées à la recherche des mécanismes d'ozonation de composés lignocellulosiques : contribution à l'identification des sous-produits solubles en milieu aqueux". Toulouse, INPT, 1993. http://www.theses.fr/1993INPT066G.
Pełny tekst źródłaTaconnat, Jean-Marc. "Contribution à la diversification des productions de dérivés du saccharose : recherche de méthodes de séparation préparatives de mélanges de sucres simples et oligomères". Paris 12, 1991. http://www.theses.fr/1991PA120053.
Pełny tekst źródłaMcKay, Samuel. "Identity Change and Development as a Potential Explanatory Mechanism of the Outcomes of Student Exchange Experiences". Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0160.
Pełny tekst źródłaHigher education serves as a key context for identity development for emerging adults. Within this space, student exchange is becoming increasingly important. Studies show that exchange is related to numerous positive outcomes such as career success, intercultural skills, wellbeing, and positive functioning. However, relatively little is known about the mechanisms that promote development. In this thesis, a model that integrates the status, resource, and narrative models of identity along with theories of acculturation is proposed to explain the underlying mechanisms of change during exchange. In the model, identity development in the form of exploring and committing to identity alternatives is argued to be the primary underlying explanation for the outcomes of exchange. To test this model two studies were conducted based on a mixed methods framework. The first study assessed the integrated identity model with Australian and French students who completed a series of questionnaires measuring their identity, acculturation, wellbeing, career clarity, and the agentic personality before (Australians N = 203, French N = 233), during (Australian N = 111, French N = 147), and after their exchange (Australians N = 96, French N = 128). Longitudinal multilevel models and random intercept cross-lagged panel models demonstrated that exchange supported increases in identity commitment and exploration in breadth while simultaneously decreasing ruminative exploration. In terms of the mechanisms of change, the explanatory power of the identity models was mixed. Identity commitment was shown to be related to growth in the agentic personality and career calling but played a smaller role in students enhanced cultural intelligence and life satisfaction. The aim of the second study was to explore how students conceptualise the processes of change and development during exchange. Interviews were conducted with a subsample of participants (Australians N = 10, French N = 10) from the first study. Thematic analysis identified two major themes of change and associated driving experiences, which related to participants feeling more confident, while also clarifying their self-perceptions and worldviews. Three themes of influencing factors showed that students’ attitudes, previous experience, and family environments could affect exchange outcomes. The findings suggest that identity is central to development during exchange with the results aligning with the proposed identity model. The combined findings of this thesis provide novel explanations for the mechanisms of change during exchange. The research highlights the importance of identity in the development process and points to opportunities for both future studies and interventions. Further work is needed to assess explanatory potential power of the proposed model with a broader range of variables and cohorts. Nevertheless, this thesis presents an important first step in identifying and assessing the processes of change during student exchange using an identity framework
Bentahar, Omar. "Une approche contingente et dynamique des rôles du chef de projet : le cas de projets de construction de grands barrages au Maroc". Caen, 2011. http://www.theses.fr/2011CAEN0680.
Pełny tekst źródłaThe project management literature is dominated by the normative theory which is focused on the methods and management techniques and the key factors of success. Thus, it occults more or less the project management contingency and both the organizational and human resources management problematics (Shenhar, 2001). This theoretical observation coupled with the empirical one related to the failure of the major infrastructure projects are at the origin of this research on the roles of the projects managers in the constructions projects of large dams in Morocco. Our thesis asks the two following questions: how can we explain the roles diversity of the project manager in the large dams construction? How do the project manager’s roles and the characteristics of the project evolve during the course of the project? So we have achieved an empirical study on thirty three projects founded on mixed methods ; qualitative and quantitative. The results underscore the relation between the project manager’s roles and the contingent characteristics of the project (NTCP), and show that the project manager’s roles evolve I, function of the evolution of the contingent characteristics of the project (TCP). This research contributes to the development of a contingent and dynamic theory of the project manager’s roles. Thus, it calls into question the universal foundations of the project management. From the managerial point of view, it can help the project managers to organize their roles into a hierarchy and to adapt them to the contingent characteristics of the project, and the human resources directors in appointing the right project managers to different types of projects