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  • Open Access
    Authors: 
    Eyrich, Charles Beaufort;
    Country: Canada

    The exchange stiffness, Aex, is one of the key parameters controlling magnetization reversal in magnetic materials but is very difficult to measure, especially in thin films. We developed a new technique for measuring the exchange stiffness of a magnetic material based on the formation of a spin spiral within two antiferromagnetically coupled ferromagnetic films [1]. Using this method, I was able to measure the exchange stiffness of thin film Co alloyed with Cr, Fe, Ni, Pd, Pt and Ru. The results of this work showed that the rate at which a substituent element reduces the exchange stiffness is not directly related to its effect on the magnetization of the alloy. These measured trends have been understood by combining measurements of element specific magnetic moments obtained using X-ray magnetic circular dichroism (XMCD) and material specific modeling based on density functional theory (DFT) within the local density approximation (LDA). The experimental results also hint at significant reduction of the exchange stiffness at the interface that can account for the difference between our results and those obtained on bulk materials.

  • Open Access English
    Authors: 
    Morentin Etayo, Alvaro;
    Country: France

    In recent years, aircraft manufacturers have been making progress in the design of more efficient aircrafts to reduce the environmental footprint. To attain this target, aircrafts manufactures work on the replacement of the hydraulic and bleed systems for electrical systems leading to a “More Electrical Aircraft”. However, the expected mass gain is a challenge, as previous technologies have been developed and optimized for decades. The new electrical solutions need to be look into detail to be competitive with previous technologies. All degrees of freedom must be considered, that is, new technologies and architectures. In particular, an HVDC network that reduces the number of rectifier stages seems a promising solution. From the HVDC network, the different three phase AC loads will be supplied by a series of power generic inverters. As the power consumption of the different loads change during the flight mission, the same inverter is used to supply different loads. The connection between the inverters and the loads is managed by a matrix of contactors. The proposed solution also considers redundant configurations, thus increasing system robustness. The design of the innovative system is presented in this document. That is, determining the optimal trade-off between the number of power inverters and the nominal power of each generic inverter that will also impact the size of the matrix of contactors. However, to assess the combinatory problem, the mass of the different components as a function of the nominal power needs to be calculated. A design environment is therefore created to perform automatic and optimized design of power converters. The different components are described using a “direct modelling” approach and coded using “object-oriented” programming. The components are validated experimentally or by numerical simulations. The different models are coupled to an optimization environment and to a frequency solver allowing a fast calculation of the steady-state waveforms. The optimization environment performs the precise design of the different parts of the power inverter: heatsink, power module, DC filter and coupling inductor. The power inverter is designed for different values of nominal power and switching frequency. The optimization assesses as well the usage of different technologies. Finally, the results are used to determine the optimal trade-off between the number of inverters and the nominal power of each inverter using a heuristic algorithm.

  • Open Access English
    Authors: 
    Mallmann-Trenn, Frederik;
    Publisher: HAL CCSD
    Countries: France, Canada, France

    Cette thèse est consacrée à l'étude des processus stochastiques décentralisés. Parmi les exemples typiques de ces processus figurent la dynamique météorologique, la circulation automobile, la façon dont nous rencontrons nos amis, etc. Dans cette thèse, nous exploitons une large palette d'outils probabilistes permettant d'analyser des chaînes de Markov afin d'étudier un large éventail de ces processus distribués : modèle des feux de forêt (réseaux sociaux), balls-into-bins avec suppression, et des dynamiques et protocoles de consensus fondamentaux tels que Voter Model, 2-Choices, et 3-Majority. This thesis is devoted to the study of stochastic decentralized processes. Typical examples in the real world include the dynamics of weather and temperature, of traffic, the way we meet our friends, etc. We take the rich tool set from probability theoryfor the analysis of Markov Chains and employ it to study a wide range of such distributed processes: Forest Fire Model (social networks), Balls-into-Bins with Deleting Bins, and fundamental consensus dynamics and protocols such as the Voter Model, 2-Choices, and 3-Majority.

  • Open Access English
    Authors: 
    Ingram, Juliet Amy;

    This thesis considers the character and development of clerical social criticism in England between c.1540 and c.1640. It draws principally on a number of sermons and treatises that offered critiques of the prevailing structures of wealth and power or exhortations to the fulfilment of charitable obligation. The paradigm through which these texts were constructed was that of ‘complaint’, a genre that was particularly vibrant in medieval discourse and in the sermons and ‘commonwealth’ tracts of the 1540s. It will be argued that rather than eschewing this tradition, late sixteenth-century preachers appropriated and refashioned its structures, themes and authorial positioning in response to far reaching economic, social and religious change.\ud \ud Particular aspects of socio-economic change, and of their effects on the clergy in particular, are examined in the introduction. Among the themes that are particularly germane to this thesis are the history of the enclosure movement; increasing commercialisation; and changing attitudes towards the poor. The first chapter assembles a number of printed texts in order to re-examine the trajectory of clerical complaint literature in the context of these developments. The second chapter considers the potential for social and political criticism in sermons preached at the county assizes, a sub-genre of ‘occasional’ sermons that until recently has received little attention from literary scholars or historians. The latter half of the thesis offers three case studies of selected sermons by three different authors. The intention of these chapters is primarily to examine the interaction between a text and its particular local context, although attention is also paid to broader social, political and discursive developments that help shed light on the historical meaning of these sermons.\ud \ud It is thus hoped that this study will contribute particularly to the ongoing interdisciplinary work of ‘contextualising’ the early modern English sermon and of reconstructing the role and status of the parish minister. Rather than a ‘voice in the wilderness’, it is concluded, the clerical moralist was an active agent in the discursive interpretation of economic change, and in the fashioning and communication of the reputation of powerful individuals.

  • English
    Authors: 
    Fleury, Anthony;
    Publisher: Unpublished
    Country: France
    Project: NSERC

    Data are everywhere. Voluntarily or not, they are given by the user to different companies or institutions. Improvement in computing power allows now to use more efficiently these huge quantities of data. It stimulated the creation of different applications and one of them is related to healthcare technologies and well-being. This habilitation describes the work that have been done these last years on human behavior analysis and activity recognition, from different sensors, to propose applications such as rehabilitation, health and well-being evaluation, profiling of person to adapt the automation of the environment, and also activity estimation from smartphone and video sensors. Organized in three different parts, this habilitation focuses first on the analysis of automation of the human body and the measurement of some movements. With this, solutions allowing the evaluation of the person and offering real-time feedbacks (to correct a posture or a movement) are drawn. The second part focuses on the recognition of the person and of his actions, with application for instance to early recognition of actions. In this part are investigated incremental and on-line classification techniques to improve the recognition rates but also to reduce the constraints in learning stage. Finally, the last part presents the recognition of activities in smart homes, with a final application to create user profiles in automated habitations.; Les données sont de nos jours présentes partout, qu’elles soient volontairement ou invo- lontairement cédées par un utilisateur. L’augmentation des puissances de calcul permet de traiter ces données plus en profondeur et plus efficacement, ce qui a poussé différentes applications à utiliser fortement le traitement de données pour offrir un service plus important aux usagers. Parmi les utilisations de ces données, les technologies pour la santé et le bien-être sont une thématique qui se développe de plus en plus ces dernières années et qui est un champ de recherche actif. Cette habilitation décrit dix années de recherche sur l’analyse de comportement et d’activité d’une personne, à partir de différents capteurs, afin de proposer des applications allant de l’aide à la rééducation ou l’évaluation de la santé d’une personne, à l’adaptation des automatismes dans un habitat en fonction de la volonté de l’habitant, en passant par la reconnaissance d’activités par smartphone ou par caméra vidéo. Organi- sés en trois parties, ces travaux se concentrent d’abord sur l’analyse des automatismes de la personne et la mesure de certains de ses mouvements. Avec ceci, des solutions permettant l’évaluation de la personne ou permettant de faire un retour sensoriel à celle-ci (afin de lui permettre de se corriger) se dessinent. La seconde partie se concentre sur la recon- naissance de la personne et de ses actions, avec des applications notamment sur la reconnaissance précoce d’actions. Dans cette partie sont également investiguées des techniques de classification incrémentales et en ligne afin d’améliorer les taux de reconnaissance et les contraintes d’apprentissages. Enfin, la dernière partie présente la reconnaissance d’activités dans un habitat intelligent, avec comme application finale la possibilité de créer des profils utilisateurs dans ces habitats.

  • Publication . Other literature type . Thesis . 2020
    English
    Authors: 
    Lecorps, Benjamin;
    Publisher: University of British Columbia

    Routine farm management can involve painful and stressful procedures that cause negative affective states and may have long-lasting consequences. Despite a growing interest in animal welfare and affective states, few studies have explored whether housing conditions and routine farm procedures induce long-lasting negative affective states such as negative mood. The first aim of this thesis was to develop methodologies to explore whether dairy cattle show evidence of negative mood in response to common stressful conditions. For this, I first used an adapted judgment bias test to assess changes in mood following hot-iron disbudding. My results suggested that calves experience anhedonia (i.e. the reduced ability to experience pleasure) after hot-iron disbudding. Thus, I designed tests aiming to assess whether calves display anhedonia-like responses after experiencing hot-iron disbudding, regrouping and post-partum stressors including cow-calf separation. My results showed that cattle display signs of negative mood (i.e. negative judgment bias and anhedonia) in response to stressful routine farm procedures. The second aim of this thesis was to explore why individuals show strong variation in how they cope with stressors. For instance, I explored whether individual variation in expectations would predict higher vulnerability to stressors. Negative expectations (i.e. pessimism) may lead to negative perceptions, stronger responses, poor coping strategies (avoidance-based coping strategies), and poor recovery from stressors. My results show that stable differences in pessimism exist in non-weaned dairy calves and that more pessimistic animals perceive and respond more negatively to stressors. I conclude that the study of mood-related changes and individual differences help better understand how living conditions affect farm animal welfare.

  • Open Access French
    Authors: 
    Razimbaud, Fabrice;
    Country: France

    Après une présentation des principales hémoparasitoses ovines, les méthodes de diagnostic épidémio-clinique et de laboratoire sont développées. L'impact des conditions climatiques et écologiques du milieu sur l'abondance des tiques vectrices d'hémoparasites est abordé. Le Belar Joa (en basque) ou "fièvre des montagnes" correspond à une maladie touchant les Ovins lors de leur première estive. Cette maladie est connue depuis longtemps par les bergers, mais son origine n'a jamais été élucidée.

  • Open Access French
    Authors: 
    Tardif, Antoine;
    Publisher: HAL CCSD
    Country: France

    Comprendre le fonctionnement des écosystèmes est un enjeu crucial, en particulier dans un contexte de changements globaux. Afin de mieux prédire les processus écosystémiques, j'ai testé la précision et les limites des hypothèses du biomass-ratio de Grime (HBMR) et de l'annulation idiosyncratique (HAI), cette dernière étant une hypothèse originale de cette thèse. Pour cela, j'ai appliqué le principe du biomass-ratio aux traits fonctionnels, en employant la méthode des traits agrégés en communauté, pour estimer la réponse globale des espèces en mélange. La décomposition des litières plurispécifiques constitue un bon modèle biologique, pour lequel je me suis posé les questions suivantes : (1) est-ce que l'HBMR prédit bien les taux de décomposition en mélanges plurispécifiques ? ; (2) est-ce que le degré de variabilité de ces taux diminue pour des raisons biologiques avec l'augmentation de la richesse spécifique (RS) des mélanges (HAI) ? ; (3) est-ce que la variabilité des taux entre mélanges diminue quand les conditions abiotiques du site deviennent plus limitantes ? ; (4)considérant que les mélanges plus contrastés fonctionnellement sont susceptibles de développer plus d'interactions, est-ce que la déviation à la prédiction augmente avec la dispersion fonctionnelle des mélanges(" FDis ", La liberté & Legendre 2010) ? Cette thèse inclut deux expériences de décomposition en sachets à litières : (1) à Sherbrooke (QC, Canada) avec des microcosmes, impliquant des litières de six espèces d'arbres, décomposant seules et en mélanges et (2) sur trois sites au climat contrasté dans la région de Clermont-Ferrand (France) avec des litières de quatre espèces d'herbacées, décomposant seules et en mélanges. Les résultats montrent des déviations positives et négatives par rapport aux taux prédits, mais l'HBMR décrit bien la réponse moyenne des litières plurispécifiques. Bien que l'HAI ait été rejetée, les résultats montrent une convergence des taux observés vers les taux prédits quand (1) la RS des mélanges augmente, (2)l'échelle spatiale augmente et (3) le climat est plus limitant pour la décomposition. Enfin, malgré des corrélations entre FDis et interactions entre espèces dans les litières, cette relation n'est pas généralisable et l'hypothèse de corrélation positive entre FDis et déviation à l'HBMR a été rejetée. Understanding ecosystem functioning is a key goal in ecology, especially in the context of global changes. To better predict ecosystem processes, I tested the accuracy and the limits of Grime's biomass-ratio (BMRH) hypothesis and a novel idiosyncratic annulment (IAH) hypothesis. I applied the biomass-ratio to functional traits, using the community-weighted means (CWM) to estimate the global response of species in mixtures. I studied the decomposition of litter species mixtures as a biological model and asked the following questions : (1) does the BMRH predict well the decomposition rates of mixed species litters ? ; (2) does the degree of variability of these rates decrease with increasing species richness (SR) beyond that expected from purely mathematical causes (IAH) ? ; (3) does the variability of rates between mixtures decrease with less favourable abiotic conditions for decomposition ? ; (4) as more functionally contrasted mixtures are expected to develop more interactions, does the deviation from prediction increase with increasing functional dispersion in mixtures (" FDis ", Laliberté & Legendre 2010) ? This study involves two decomposition experiments using litterbags : (1) at Sherbrooke (QC, Canada), in microcosms, involving litters from six tree species, decomposed alone and in mixtures and (2) in three climatically contrasted sites in the region of Clermont-Ferrand (France) with litters from four herbaceous species, decomposed alone and in mixtures. Despite both positive and negative deviations from expectation occurring at all levels of SR, the BMRH well described the average response of mixed species litters. Although I rejected the IAH, the results showed a convergence to the predicted values based on CWM with (1) increasing the SR in mixtures, (2) increasing the spatial scale of the study and (3) a less favourable climate to decomposition. Finally, although there was a correlation between litter interactions and functional divergence, this relationship was not generalizable and I rejected the hypothesis of a positive correlation between FDis and the deviations from BMRH.

  • Open Access English
    Authors: 
    Wei, Qi;
    Country: France

    Hyperspectral (HS) imaging, which consists of acquiring a same scene in several hundreds of contiguous spectral bands (a three dimensional data cube), has opened a new range of relevant applications, such as target detection [MS02], classification [C.-03] and spectral unmixing [BDPD+12]. However, while HS sensors provide abundant spectral information, their spatial resolution is generally more limited. Thus, fusing the HS image with other highly resolved images of the same scene, such as multispectral (MS) or panchromatic (PAN) images is an interesting problem. The problem of fusing a high spectral and low spatial resolution image with an auxiliary image of higher spatial but lower spectral resolution, also known as multi-resolution image fusion, has been explored for many years [AMV+11]. From an application point of view, this problem is also important as motivated by recent national programs, e.g., the Japanese next-generation space-borne hyperspectral image suite (HISUI), which fuses co-registered MS and HS images acquired over the same scene under the same conditions [YI13]. Bayesian fusion allows for an intuitive interpretation of the fusion process via the posterior distribution. Since the fusion problem is usually ill-posed, the Bayesian methodology offers a convenient way to regularize the problem by defining appropriate prior distribution for the scene of interest. The aim of this thesis is to study new multi-band image fusion algorithms to enhance the resolution of hyperspectral image. In the first chapter, a hierarchical Bayesian framework is proposed for multi-band image fusion by incorporating forward model, statistical assumptions and Gaussian prior for the target image to be restored. To derive Bayesian estimators associated with the resulting posterior distribution, two algorithms based on Monte Carlo sampling and optimization strategy have been developed. In the second chapter, a sparse regularization using dictionaries learned from the observed images is introduced as an alternative of the naive Gaussian prior proposed in Chapter 1. instead of Gaussian prior is introduced to regularize the ill-posed problem. Identifying the supports jointly with the dictionaries circumvented the difficulty inherent to sparse coding. To minimize the target function, an alternate optimization algorithm has been designed, which accelerates the fusion process magnificently comparing with the simulation-based method. In the third chapter, by exploiting intrinsic properties of the blurring and downsampling matrices, a much more efficient fusion method is proposed thanks to a closed-form solution for the Sylvester matrix equation associated with maximizing the likelihood. The proposed solution can be embedded into an alternating direction method of multipliers or a block coordinate descent method to incorporate different priors or hyper-priors for the fusion problem, allowing for Bayesian estimators. In the last chapter, a joint multi-band image fusion and unmixing scheme is proposed by combining the well admitted linear spectral mixture model and the forward model. The joint fusion and unmixing problem is solved in an alternating optimization framework, mainly consisting of solving a Sylvester equation and projecting onto a simplex resulting from the non-negativity and sum-to-one constraints. The simulation results conducted on synthetic and semi-synthetic images illustrate the advantages of the developed Bayesian estimators, both qualitatively and quantitatively.

  • Open Access English
    Authors: 
    Foucras, Myriam;
    Country: France

    Since the development of the GPS, the global navigation satellite systems (GNSS) have been widely diversified: maintenance, modernization and deployment of new systems such as the European Galileo. In addition, the number of GNSS signals applications, based on the use of GNSS signals, is increasing. To meet these new challenges and requirements, GNSS receivers are constantly evolving. A new trend is the development of software receiver which processes the GNSS signal in a software way unlike hardware receiver, equipping our vehicles, smartphones, for example. This thesis is part of a common project between a laboratory and a company, consisting of the development of a software receiver tracking GPS L1 C/A and Galileo E1 OS. The more specific aim of the thesis is to study the acquisition, first signal processing which provides a rough estimation of the incoming signal parameters. This work focuses particularly the low power signals, an acquisition threshold is set at 27 dB-Hz considered as a representative of urban or degraded environments. It is important to note that the success of the acquisition of such signals should be at least 9 times out of 10, without any aid or knowledge of almanac or ephemeris. Initially, a solid theoretical study of the acquisition performance and sources of degradation is conducted. One of them is the bit transitions due to the presence of the navigation message and the secondary code on pilot component of the new signals. It is thus highlighted the need to use a Transition-Insensitive acquisition method. Secondly, an innovative method, the Double-Block Zero-Padding Transition-Insensitive (DBZPTI) is developed to permit efficiently the acquisition of Galileo E1 OS signal. It takes part in the development of the global acquisition strategy, which should provide an estimate of the Doppler frequency and code delay, fine and reliable, for a satisfactory signal tracking.

Advanced search in
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arrow_drop_down
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The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
90 Research products, page 1 of 9
  • Open Access
    Authors: 
    Eyrich, Charles Beaufort;
    Country: Canada

    The exchange stiffness, Aex, is one of the key parameters controlling magnetization reversal in magnetic materials but is very difficult to measure, especially in thin films. We developed a new technique for measuring the exchange stiffness of a magnetic material based on the formation of a spin spiral within two antiferromagnetically coupled ferromagnetic films [1]. Using this method, I was able to measure the exchange stiffness of thin film Co alloyed with Cr, Fe, Ni, Pd, Pt and Ru. The results of this work showed that the rate at which a substituent element reduces the exchange stiffness is not directly related to its effect on the magnetization of the alloy. These measured trends have been understood by combining measurements of element specific magnetic moments obtained using X-ray magnetic circular dichroism (XMCD) and material specific modeling based on density functional theory (DFT) within the local density approximation (LDA). The experimental results also hint at significant reduction of the exchange stiffness at the interface that can account for the difference between our results and those obtained on bulk materials.

  • Open Access English
    Authors: 
    Morentin Etayo, Alvaro;
    Country: France

    In recent years, aircraft manufacturers have been making progress in the design of more efficient aircrafts to reduce the environmental footprint. To attain this target, aircrafts manufactures work on the replacement of the hydraulic and bleed systems for electrical systems leading to a “More Electrical Aircraft”. However, the expected mass gain is a challenge, as previous technologies have been developed and optimized for decades. The new electrical solutions need to be look into detail to be competitive with previous technologies. All degrees of freedom must be considered, that is, new technologies and architectures. In particular, an HVDC network that reduces the number of rectifier stages seems a promising solution. From the HVDC network, the different three phase AC loads will be supplied by a series of power generic inverters. As the power consumption of the different loads change during the flight mission, the same inverter is used to supply different loads. The connection between the inverters and the loads is managed by a matrix of contactors. The proposed solution also considers redundant configurations, thus increasing system robustness. The design of the innovative system is presented in this document. That is, determining the optimal trade-off between the number of power inverters and the nominal power of each generic inverter that will also impact the size of the matrix of contactors. However, to assess the combinatory problem, the mass of the different components as a function of the nominal power needs to be calculated. A design environment is therefore created to perform automatic and optimized design of power converters. The different components are described using a “direct modelling” approach and coded using “object-oriented” programming. The components are validated experimentally or by numerical simulations. The different models are coupled to an optimization environment and to a frequency solver allowing a fast calculation of the steady-state waveforms. The optimization environment performs the precise design of the different parts of the power inverter: heatsink, power module, DC filter and coupling inductor. The power inverter is designed for different values of nominal power and switching frequency. The optimization assesses as well the usage of different technologies. Finally, the results are used to determine the optimal trade-off between the number of inverters and the nominal power of each inverter using a heuristic algorithm.

  • Open Access English
    Authors: 
    Mallmann-Trenn, Frederik;
    Publisher: HAL CCSD
    Countries: France, Canada, France

    Cette thèse est consacrée à l'étude des processus stochastiques décentralisés. Parmi les exemples typiques de ces processus figurent la dynamique météorologique, la circulation automobile, la façon dont nous rencontrons nos amis, etc. Dans cette thèse, nous exploitons une large palette d'outils probabilistes permettant d'analyser des chaînes de Markov afin d'étudier un large éventail de ces processus distribués : modèle des feux de forêt (réseaux sociaux), balls-into-bins avec suppression, et des dynamiques et protocoles de consensus fondamentaux tels que Voter Model, 2-Choices, et 3-Majority. This thesis is devoted to the study of stochastic decentralized processes. Typical examples in the real world include the dynamics of weather and temperature, of traffic, the way we meet our friends, etc. We take the rich tool set from probability theoryfor the analysis of Markov Chains and employ it to study a wide range of such distributed processes: Forest Fire Model (social networks), Balls-into-Bins with Deleting Bins, and fundamental consensus dynamics and protocols such as the Voter Model, 2-Choices, and 3-Majority.

  • Open Access English
    Authors: 
    Ingram, Juliet Amy;

    This thesis considers the character and development of clerical social criticism in England between c.1540 and c.1640. It draws principally on a number of sermons and treatises that offered critiques of the prevailing structures of wealth and power or exhortations to the fulfilment of charitable obligation. The paradigm through which these texts were constructed was that of ‘complaint’, a genre that was particularly vibrant in medieval discourse and in the sermons and ‘commonwealth’ tracts of the 1540s. It will be argued that rather than eschewing this tradition, late sixteenth-century preachers appropriated and refashioned its structures, themes and authorial positioning in response to far reaching economic, social and religious change.\ud \ud Particular aspects of socio-economic change, and of their effects on the clergy in particular, are examined in the introduction. Among the themes that are particularly germane to this thesis are the history of the enclosure movement; increasing commercialisation; and changing attitudes towards the poor. The first chapter assembles a number of printed texts in order to re-examine the trajectory of clerical complaint literature in the context of these developments. The second chapter considers the potential for social and political criticism in sermons preached at the county assizes, a sub-genre of ‘occasional’ sermons that until recently has received little attention from literary scholars or historians. The latter half of the thesis offers three case studies of selected sermons by three different authors. The intention of these chapters is primarily to examine the interaction between a text and its particular local context, although attention is also paid to broader social, political and discursive developments that help shed light on the historical meaning of these sermons.\ud \ud It is thus hoped that this study will contribute particularly to the ongoing interdisciplinary work of ‘contextualising’ the early modern English sermon and of reconstructing the role and status of the parish minister. Rather than a ‘voice in the wilderness’, it is concluded, the clerical moralist was an active agent in the discursive interpretation of economic change, and in the fashioning and communication of the reputation of powerful individuals.

  • English
    Authors: 
    Fleury, Anthony;
    Publisher: Unpublished
    Country: France
    Project: NSERC

    Data are everywhere. Voluntarily or not, they are given by the user to different companies or institutions. Improvement in computing power allows now to use more efficiently these huge quantities of data. It stimulated the creation of different applications and one of them is related to healthcare technologies and well-being. This habilitation describes the work that have been done these last years on human behavior analysis and activity recognition, from different sensors, to propose applications such as rehabilitation, health and well-being evaluation, profiling of person to adapt the automation of the environment, and also activity estimation from smartphone and video sensors. Organized in three different parts, this habilitation focuses first on the analysis of automation of the human body and the measurement of some movements. With this, solutions allowing the evaluation of the person and offering real-time feedbacks (to correct a posture or a movement) are drawn. The second part focuses on the recognition of the person and of his actions, with application for instance to early recognition of actions. In this part are investigated incremental and on-line classification techniques to improve the recognition rates but also to reduce the constraints in learning stage. Finally, the last part presents the recognition of activities in smart homes, with a final application to create user profiles in automated habitations.; Les données sont de nos jours présentes partout, qu’elles soient volontairement ou invo- lontairement cédées par un utilisateur. L’augmentation des puissances de calcul permet de traiter ces données plus en profondeur et plus efficacement, ce qui a poussé différentes applications à utiliser fortement le traitement de données pour offrir un service plus important aux usagers. Parmi les utilisations de ces données, les technologies pour la santé et le bien-être sont une thématique qui se développe de plus en plus ces dernières années et qui est un champ de recherche actif. Cette habilitation décrit dix années de recherche sur l’analyse de comportement et d’activité d’une personne, à partir de différents capteurs, afin de proposer des applications allant de l’aide à la rééducation ou l’évaluation de la santé d’une personne, à l’adaptation des automatismes dans un habitat en fonction de la volonté de l’habitant, en passant par la reconnaissance d’activités par smartphone ou par caméra vidéo. Organi- sés en trois parties, ces travaux se concentrent d’abord sur l’analyse des automatismes de la personne et la mesure de certains de ses mouvements. Avec ceci, des solutions permettant l’évaluation de la personne ou permettant de faire un retour sensoriel à celle-ci (afin de lui permettre de se corriger) se dessinent. La seconde partie se concentre sur la recon- naissance de la personne et de ses actions, avec des applications notamment sur la reconnaissance précoce d’actions. Dans cette partie sont également investiguées des techniques de classification incrémentales et en ligne afin d’améliorer les taux de reconnaissance et les contraintes d’apprentissages. Enfin, la dernière partie présente la reconnaissance d’activités dans un habitat intelligent, avec comme application finale la possibilité de créer des profils utilisateurs dans ces habitats.

  • Publication . Other literature type . Thesis . 2020
    English
    Authors: 
    Lecorps, Benjamin;
    Publisher: University of British Columbia

    Routine farm management can involve painful and stressful procedures that cause negative affective states and may have long-lasting consequences. Despite a growing interest in animal welfare and affective states, few studies have explored whether housing conditions and routine farm procedures induce long-lasting negative affective states such as negative mood. The first aim of this thesis was to develop methodologies to explore whether dairy cattle show evidence of negative mood in response to common stressful conditions. For this, I first used an adapted judgment bias test to assess changes in mood following hot-iron disbudding. My results suggested that calves experience anhedonia (i.e. the reduced ability to experience pleasure) after hot-iron disbudding. Thus, I designed tests aiming to assess whether calves display anhedonia-like responses after experiencing hot-iron disbudding, regrouping and post-partum stressors including cow-calf separation. My results showed that cattle display signs of negative mood (i.e. negative judgment bias and anhedonia) in response to stressful routine farm procedures. The second aim of this thesis was to explore why individuals show strong variation in how they cope with stressors. For instance, I explored whether individual variation in expectations would predict higher vulnerability to stressors. Negative expectations (i.e. pessimism) may lead to negative perceptions, stronger responses, poor coping strategies (avoidance-based coping strategies), and poor recovery from stressors. My results show that stable differences in pessimism exist in non-weaned dairy calves and that more pessimistic animals perceive and respond more negatively to stressors. I conclude that the study of mood-related changes and individual differences help better understand how living conditions affect farm animal welfare.

  • Open Access French
    Authors: 
    Razimbaud, Fabrice;
    Country: France

    Après une présentation des principales hémoparasitoses ovines, les méthodes de diagnostic épidémio-clinique et de laboratoire sont développées. L'impact des conditions climatiques et écologiques du milieu sur l'abondance des tiques vectrices d'hémoparasites est abordé. Le Belar Joa (en basque) ou "fièvre des montagnes" correspond à une maladie touchant les Ovins lors de leur première estive. Cette maladie est connue depuis longtemps par les bergers, mais son origine n'a jamais été élucidée.

  • Open Access French
    Authors: 
    Tardif, Antoine;
    Publisher: HAL CCSD
    Country: France

    Comprendre le fonctionnement des écosystèmes est un enjeu crucial, en particulier dans un contexte de changements globaux. Afin de mieux prédire les processus écosystémiques, j'ai testé la précision et les limites des hypothèses du biomass-ratio de Grime (HBMR) et de l'annulation idiosyncratique (HAI), cette dernière étant une hypothèse originale de cette thèse. Pour cela, j'ai appliqué le principe du biomass-ratio aux traits fonctionnels, en employant la méthode des traits agrégés en communauté, pour estimer la réponse globale des espèces en mélange. La décomposition des litières plurispécifiques constitue un bon modèle biologique, pour lequel je me suis posé les questions suivantes : (1) est-ce que l'HBMR prédit bien les taux de décomposition en mélanges plurispécifiques ? ; (2) est-ce que le degré de variabilité de ces taux diminue pour des raisons biologiques avec l'augmentation de la richesse spécifique (RS) des mélanges (HAI) ? ; (3) est-ce que la variabilité des taux entre mélanges diminue quand les conditions abiotiques du site deviennent plus limitantes ? ; (4)considérant que les mélanges plus contrastés fonctionnellement sont susceptibles de développer plus d'interactions, est-ce que la déviation à la prédiction augmente avec la dispersion fonctionnelle des mélanges(" FDis ", La liberté & Legendre 2010) ? Cette thèse inclut deux expériences de décomposition en sachets à litières : (1) à Sherbrooke (QC, Canada) avec des microcosmes, impliquant des litières de six espèces d'arbres, décomposant seules et en mélanges et (2) sur trois sites au climat contrasté dans la région de Clermont-Ferrand (France) avec des litières de quatre espèces d'herbacées, décomposant seules et en mélanges. Les résultats montrent des déviations positives et négatives par rapport aux taux prédits, mais l'HBMR décrit bien la réponse moyenne des litières plurispécifiques. Bien que l'HAI ait été rejetée, les résultats montrent une convergence des taux observés vers les taux prédits quand (1) la RS des mélanges augmente, (2)l'échelle spatiale augmente et (3) le climat est plus limitant pour la décomposition. Enfin, malgré des corrélations entre FDis et interactions entre espèces dans les litières, cette relation n'est pas généralisable et l'hypothèse de corrélation positive entre FDis et déviation à l'HBMR a été rejetée. Understanding ecosystem functioning is a key goal in ecology, especially in the context of global changes. To better predict ecosystem processes, I tested the accuracy and the limits of Grime's biomass-ratio (BMRH) hypothesis and a novel idiosyncratic annulment (IAH) hypothesis. I applied the biomass-ratio to functional traits, using the community-weighted means (CWM) to estimate the global response of species in mixtures. I studied the decomposition of litter species mixtures as a biological model and asked the following questions : (1) does the BMRH predict well the decomposition rates of mixed species litters ? ; (2) does the degree of variability of these rates decrease with increasing species richness (SR) beyond that expected from purely mathematical causes (IAH) ? ; (3) does the variability of rates between mixtures decrease with less favourable abiotic conditions for decomposition ? ; (4) as more functionally contrasted mixtures are expected to develop more interactions, does the deviation from prediction increase with increasing functional dispersion in mixtures (" FDis ", Laliberté & Legendre 2010) ? This study involves two decomposition experiments using litterbags : (1) at Sherbrooke (QC, Canada), in microcosms, involving litters from six tree species, decomposed alone and in mixtures and (2) in three climatically contrasted sites in the region of Clermont-Ferrand (France) with litters from four herbaceous species, decomposed alone and in mixtures. Despite both positive and negative deviations from expectation occurring at all levels of SR, the BMRH well described the average response of mixed species litters. Although I rejected the IAH, the results showed a convergence to the predicted values based on CWM with (1) increasing the SR in mixtures, (2) increasing the spatial scale of the study and (3) a less favourable climate to decomposition. Finally, although there was a correlation between litter interactions and functional divergence, this relationship was not generalizable and I rejected the hypothesis of a positive correlation between FDis and the deviations from BMRH.

  • Open Access English
    Authors: 
    Wei, Qi;
    Country: France

    Hyperspectral (HS) imaging, which consists of acquiring a same scene in several hundreds of contiguous spectral bands (a three dimensional data cube), has opened a new range of relevant applications, such as target detection [MS02], classification [C.-03] and spectral unmixing [BDPD+12]. However, while HS sensors provide abundant spectral information, their spatial resolution is generally more limited. Thus, fusing the HS image with other highly resolved images of the same scene, such as multispectral (MS) or panchromatic (PAN) images is an interesting problem. The problem of fusing a high spectral and low spatial resolution image with an auxiliary image of higher spatial but lower spectral resolution, also known as multi-resolution image fusion, has been explored for many years [AMV+11]. From an application point of view, this problem is also important as motivated by recent national programs, e.g., the Japanese next-generation space-borne hyperspectral image suite (HISUI), which fuses co-registered MS and HS images acquired over the same scene under the same conditions [YI13]. Bayesian fusion allows for an intuitive interpretation of the fusion process via the posterior distribution. Since the fusion problem is usually ill-posed, the Bayesian methodology offers a convenient way to regularize the problem by defining appropriate prior distribution for the scene of interest. The aim of this thesis is to study new multi-band image fusion algorithms to enhance the resolution of hyperspectral image. In the first chapter, a hierarchical Bayesian framework is proposed for multi-band image fusion by incorporating forward model, statistical assumptions and Gaussian prior for the target image to be restored. To derive Bayesian estimators associated with the resulting posterior distribution, two algorithms based on Monte Carlo sampling and optimization strategy have been developed. In the second chapter, a sparse regularization using dictionaries learned from the observed images is introduced as an alternative of the naive Gaussian prior proposed in Chapter 1. instead of Gaussian prior is introduced to regularize the ill-posed problem. Identifying the supports jointly with the dictionaries circumvented the difficulty inherent to sparse coding. To minimize the target function, an alternate optimization algorithm has been designed, which accelerates the fusion process magnificently comparing with the simulation-based method. In the third chapter, by exploiting intrinsic properties of the blurring and downsampling matrices, a much more efficient fusion method is proposed thanks to a closed-form solution for the Sylvester matrix equation associated with maximizing the likelihood. The proposed solution can be embedded into an alternating direction method of multipliers or a block coordinate descent method to incorporate different priors or hyper-priors for the fusion problem, allowing for Bayesian estimators. In the last chapter, a joint multi-band image fusion and unmixing scheme is proposed by combining the well admitted linear spectral mixture model and the forward model. The joint fusion and unmixing problem is solved in an alternating optimization framework, mainly consisting of solving a Sylvester equation and projecting onto a simplex resulting from the non-negativity and sum-to-one constraints. The simulation results conducted on synthetic and semi-synthetic images illustrate the advantages of the developed Bayesian estimators, both qualitatively and quantitatively.

  • Open Access English
    Authors: 
    Foucras, Myriam;
    Country: France

    Since the development of the GPS, the global navigation satellite systems (GNSS) have been widely diversified: maintenance, modernization and deployment of new systems such as the European Galileo. In addition, the number of GNSS signals applications, based on the use of GNSS signals, is increasing. To meet these new challenges and requirements, GNSS receivers are constantly evolving. A new trend is the development of software receiver which processes the GNSS signal in a software way unlike hardware receiver, equipping our vehicles, smartphones, for example. This thesis is part of a common project between a laboratory and a company, consisting of the development of a software receiver tracking GPS L1 C/A and Galileo E1 OS. The more specific aim of the thesis is to study the acquisition, first signal processing which provides a rough estimation of the incoming signal parameters. This work focuses particularly the low power signals, an acquisition threshold is set at 27 dB-Hz considered as a representative of urban or degraded environments. It is important to note that the success of the acquisition of such signals should be at least 9 times out of 10, without any aid or knowledge of almanac or ephemeris. Initially, a solid theoretical study of the acquisition performance and sources of degradation is conducted. One of them is the bit transitions due to the presence of the navigation message and the secondary code on pilot component of the new signals. It is thus highlighted the need to use a Transition-Insensitive acquisition method. Secondly, an innovative method, the Double-Block Zero-Padding Transition-Insensitive (DBZPTI) is developed to permit efficiently the acquisition of Galileo E1 OS signal. It takes part in the development of the global acquisition strategy, which should provide an estimate of the Doppler frequency and code delay, fine and reliable, for a satisfactory signal tracking.