Il a été suggéré que la similarité physique entre un observateur et une action observée facilite la perception et la compréhension d’action. Par exemple, l’observation d’un acteur exécutant des gestes de la main ayant une signification culturelle est associée à une augmentation de l’excitabilité corticospinale lorsque les deux individus sont de la même ethnicité (Molnar-Szakacs et al., 2007). La perception tactile serait également facilitée lorsqu’un individu regarde un modèle de sa propre race être touché (Serino et al., 2009), tandis que des études en imagerie cérébrale fonctionnelle suggèrent la présence d’activations plus importantes dans le cortex cingulaire lorsqu’un sujet observe une personne de son propre groupe racial ressentir de la douleur (Xu et al., 2009). Certaines études ont lié ces résultats à un mécanisme de résonance motrice, possiblement associé au système des neurones miroirs (SNM), suggérant que la représentation de l’action dans les aires motrices est facilitée par la similarité physique. Toutefois, la grande majorité des stimuli utilisés dans ces études comportent une composante émotionnelle ou culturelle pouvant masquer les effets purement moteurs liant la similarité physique à un mécanisme de résonance motrice. De plus, la sélectivité de l’activation du SNM face à des stimuli biologiques a récemment été remise en question en raison de biais méthodologiques. La présente thèse présente trois études visant à évaluer l’effet de la similarité physique et des caractéristiques biologiques d’un mouvement sur la résonance motrice à l’aide de mesures comportementales et neurophysiologiques. À cet effet, l’imitation automatique de mouvements de la main, l’excitabilité corticospinale et la désynchronisation du rythme électroencéphalographique mu ont servi de marqueurs de l’activité du SNM. Dans les trois études présentées, la couleur de la peau et l’aspect biologique du stimulus observé ou imité ont été systématiquement manipulés. Nos données confirment la sélectivité du SNM pour le mouvement biologique en démontrant une réponse imitative plus rapide et une désynchronisation du rythme mu plus prononcée lors de la présentation de stimuli biologiques comparativement à des stimuli non-biologiques répliquant les aspects physiques du mouvement humain. Les deux mêmes mesures montrent une réponse neurophysiologique et comportementale équivalente lorsque l’action est exécutée par un agent de couleur similaire ou dissimilaire au participant. Nous rapportons aussi un effet surprenant de la similarité physique sur l’excitabilité corticospinale, où l’observation d’une action exécutée par un agent de couleur différente est associée à une activation plus grande du cortex moteur primaire droit de participants de sexe féminin. Prises dans leur ensemble, ces données suggèrent que la similarité physique avec une action observée ne module généralement pas l’activité du SNM au niveau des aires sensorimotrices en l’absence de composantes culturelles et émotionnelles. De plus, les résultats présentés suggèrent que le SNM est sélectif au mouvement biologique plutôt qu’à l’aspect kinématique du mouvement. / It has been suggested that physical similarity with an observed model facilitates action perception and understanding. For example, increased corticospinal excitability is found in participants observing actors of their own ethnicity performing culture-specific hand movements (Molnar-Szakacs et al., 2007). Tactile perception is also said to be increased when individuals watch a model of the same race being touched (Serino et al., 2009). Moreover, imaging data suggest that stronger activations are observed in the cingulate cortex when a subject observes a person of their own race feeling pain (Xu et al., 2009). Some studies have linked these findings with a motor resonance mechanism, possibly associated with the mirror neuron system (MNS), suggesting that action representation in motor areas is facilitated by physical similarity. However, most of the observed stimuli in those studies include emotional or cultural components, which may blur the link between physical similarity and motor resonance per se. The present thesis is comprised of three studies that aimed at evaluating the effect of physical similarity on motor resonance using stimuli that are purely motor in nature. The effect of physical similarity on motor responses during action observation was assessed with behavioral and electrophysiological measures. To this end, imitation of simple finger movements, as well as corticospinal excitability and mu rhythm desynchronization during passive observation of simple finger movements was evaluated, using stimuli that were similar or dissimilar to the participant in terms of skin color. In line with previous results, observation of biological movement resulted in faster reaction times and greater mu desynchronization compared to non-biological movement. Physical similarity with the imitated or observed hand did not affect imitation speed or mu desynchronization. It did, however, have a surprising effect on corticospinal excitability, where the amplitude of transcranial magnetic stimulation-induced motor evoked potentials was greater in the right hemisphere of female participants observing hand movement executed by hands of a different color. These data suggest that physical similarity with an observed action in terms of skin color does not modulate MNS activity in sensorimotor cortex when cultural and emotional components are absent. The present results also strengthen the notion that the motor cortex node of the MNS is tuned to the biological nature of an observed action.

[pt] Esta dissertação enfoca o enlace direto de sistemas MIMO multiusuário com pré-codificação onde a estação base e os terminais dos usuários possuem múltiplas antenas mas transmitem e recebem, respectivamente, símbolos de informação através de subconjuntos selecionados de seus conjuntos de antenas. O trabalho considera sistemas que utilizam técnicas de précodificação linear como Zero Forcing (ZF) e Minimum Mean Square Error (MMSE). Expressões gerais que descrevem os sistemas e relacionam a energia gasta na transmissão com a energia disponível para a detecção em cada usuário são apresentadas. Com base nestas relações, um procedimento para seleção de antenas na transmissão é proposto visando a minimização da probabilidade de erro. Um algoritmo de busca não exaustiva denominado ITES (Iterative Search) foi desenvolvido e testado e mostrou-se capaz de, com apenas uma pequena fração do esforço computacional, fornecer um desempenho próximo ao da seleção ótima, que demanda uma busca exaustiva. A seleção de antenas na recepção é também efetuada usando um critério de otimização semelhante. O caso geral da seleção conjunta de antenas na transmissão e na recepção contempla a combinação de ambas estratégias, resultando na redução da complexidade tanto na estação base, quanto nos terminais dos usuários. Os resultados de desempenho em termos da taxa de erro de bit, obtidos por meio de simulações e abordagem semianalítica, são apresentados para diferentes cenários. / [en] This thesis focuses on the downlink of a multiuser multiple-input multiple-output (MU-MIMO) systems where the Base Station (BS) and the users stations (UEs) transmit and receive information symbols, respectively, by selected subset of their antennas. The performance of the system is evaluated employing linear precoding techniques as Zero Forcing (ZF) and Minimum Mean Square Error (MMSE). A general model to describe the system and expressions that relate the energy spent in transmission with the energy available for detection at each user are presented. A transmit antenna selection procedure is proposed aiming at the minimization of the detection error probability. A suboptimal search algorithm, called ITES (Iterative Search), able to deliver a performance close to the one resulting from the optimal exhaustive search selection is also proposed. The receive antenna selection is also performed using a similar optimization criterion. Joint antennas selection at the transmitter and receiver contemplates the efficient combination of both strategies, leading to a complexity reduction in BS and UEs. BER performance results, obtained via simulation and semi-analytical approaches, are presented for different scenarios.

Cette thèse étudie deux modèles de réalisabilité pour la logique classique construits sur la sémantique des jeux HO, interprétant la logique, l'arithmétique et l'analyse classiques directement par des programmes manipulant un espace de stockage d'ordre supérieur.La non-innocence en jeux HO autorise les références d'ordre supérieur, et le non parenthésage révèle la CPS des jeux HO et fournit une catégorie de continuations dans laquelle interpréter le lambda-mu calcul de Parigot. Deux modèles de réalisabilité sont construits sur cette interprétation calculatoire directe des preuves classiques.Le premier repose sur l'orthogonalité, comme celui de Krivine, mais il est simplement typé et au premier ordre. En l'absence de codage de l'absurdité au second ordre, une mu-variable libre dans les réaliseurs permet l'extraction. Nous définissons un bar-récurseur et prouvons qu'il réalise l'axiome du choix dépendant, utilisant deux conséquences de la structure de CPO du modèle de jeux: toute fonction sur les entiers (même non calculable) existe dans le modèle, et toute fonctionnelle sur des séquences est Scott-continue. La bar-récursion est habituellement utilisée pour réaliser intuitionnistiquement le « double negation shift » et en déduire la traduction négative de l'axiome du choix. Ici, nous réalisons directement l'axiome du choix dans un cadre classique.Le second, très spécifique au modèle de jeux, repose sur des conditions de gain: des ensembles de positions d'un jeu munis de propriétés de cohérence. Un réaliseur est alors une stratégie dont les positions sont toutes gagnantes. / This thesis investigates two realizability models for classical logic built on HO game semantics. The main motivation is to have a direct computational interpretation of classical logic, arithmetic and analysis with programs manipulating a higher-order store.Relaxing the innocence condition in HO games provides higher-order references, and dropping the well-bracketing of strategies reveals the CPS of HO games and gives a category of continuations in which we can interpret Parigot's lambda-mu calculus. This permits a direct computational interpretation of classical proofs from which we build two realizability models.The first model is orthogonality-based, as the one of Krivine. However, it is simply-typed and first-order. This means that we do not use a second-order coding of falsity, and extraction is handled by considering realizers with a free mu-variable. We provide a bar-recursor in this model and prove that it realizes the axiom of dependent choice, relying on two consequences of the CPO structure of the games model: every function on natural numbers (possibly non computable) exists in the model, and every functional on sequences is Scott-continuous. Usually, bar-recursion is used to intuitionistically realize the double negation shift and consequently the negative translation of the axiom of choice. Here, we directly realize the axiom of choice in a classical setting.The second model relies on winning conditions and is very specific to the games model. A winning condition is a set of positions in a game which satisfies some coherence properties, and a realizer of a formula is then a strategy which positions are all winning.

Made available in DSpace on 2016-03-15T19:39:55Z (GMT). No. of bitstreams: 1 Olivia Morgan Lapenta.pdf: 1151745 bytes, checksum: 91e51a2bad20664489c6aae6c59924b6 (MD5) Previous issue date: 2012-08-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Mental Simulation theory suggests activation of the motor network during imagery and execution of movements, similarly to the activation during observation and execution of actions, which is mediated by the Mirror Neuron System. This activation can be measured using eletroencefalography register of Mu rhythm suppression. It is propose that motor network activation and therefore increase of cortical excitability at primary motor cortex and Mu dessynchronization are due to premotor Miror-Neuron System inputs. Transcranial direct current stimulation is a neuromodulation technique that induce facilitation and inhibition of neural firing leading to enhance or decrease in cortical excitability, respectively. Thus, we propose to evaluate the polarity dependent effects of this technique in the Mu rhythm during biological and non-biological movements observation and imagery tasks. Therefore we applied anodal, cathodal and sham stimulation in 21 male subjects (mean age 23.8+3,06), over left primary motor cortex (2mA for 20min) and immediately after we registered the electroencephalography considering the electrodes C3, C4 and surrounding C3 and C4 and Cz. Analyses of C3 and C4 showed significant effects according to Movement (p=0.005), and also for the interactions between type of stimulation and hemisphere (p=0.04) and type of stimulation, movement and hemisphere (p=0.02). Surrounding electrodes analyses revealed significant effect for the interaction between stimulation type, task condition and movement type (p=0.03). Thus, the main findings of this study were i. Mu suppression for biological movement (in both imagery and observation) of the hand region in the contralateral hemisphere after sham stimulation, ii. reverse effect for the surrounding electrodes during imagery condition and iii. polarity-dependent neuromodulation of the Mu rhythm. The results are discussed considering focal ERD/ surrounding ERS according to the type of task. We concluded that there are contralateral focal Mu dessynchronization during observation and imagery of biological movements together with syncronizarion of the motor areas not involved in the task only for the imagery condition and that transcranial direct current stimulation has a significant effect under the entire electrode and according to the applied polarity. The use of transcranial direct current stimulation followed by observation and imagery tasks might be an interesting intervention strategy for disturbances involving motor ability impairment as well as deficits related to imitation and comprehension of other s actions. / A teoria de simulação mental sugere ativação da rede neural motora durante mentalização e execução de movimentos, de maneira análoga à ativação em observação e execução de ações, o que é mediado pelo Sistema de Neurônios-Espelho. Esta ativação pode ser mensurada por supressão do ritmo Mu registrado por eletroencefalografia. É proposto que a ativação de áreas motoras e, portanto, o aumento de excitabilidade cortical em cortex motor primário e a dessincronização do ritmo Mu ocorram em consequência de insumo proveniente do Sistema Neurônios-Espelho pré-motor. A estimulação transcraniana por corrente contínua consiste numa técnica de neuromodulação por facilitação e inibição de disparo neuronal levando a aumento e redução de excitabilidade cortical, respectivamente. Assim, foi proposto avaliar os efeitos polaridade dependentes desta técnica sobre ritmo Mu durante tarefas de observação e mentalização de movimentos biológicos e não biológicos. Para tal, aplicamos estimulação anódica, catódica e placebo em 21 homens destros (idade média de 23.8+3,06), sobre córtex motor primário esquerdo (2mA por 20min) e, em seguida foi feito o registro eletroencefalográfico considerando os eletrodos C3, C4 e entorno de C3 e C4 e Cz. A análise de C3 e C4 apresentou efeitos significativos quanto ao tipo de Movimento (p=0.005) e ainda quanto as interações entre tipo de estimulação e hemisfério (p=0.04) e tipo de estimulação, de movimento e hemisfério (p=0.02). A análise dos eletrodos do entorno revelou efeito significativo para a interação entre tipo de estimulação, condição da tarefa e tipo de movimento (p=0.03). Assim, os principais achados do estudo foram i. supressão de Mu para movimento biológico (em mentalização e observação) da região da mão em hemisfério contralateral após estimulação placebo, ii. efeitos inversos para eletrodos de entorno em condição de mentalização e iii. neuromodulação polaridade dependente de ritmo Mu. Os resultados de oscilação de Mu são discutidos considerando ERD focal/ ERS entorno de acordo com o tipo de tarefa. Concluímos que há dessincronização contralateral focal de Mu durante observação e mentalização de movimentos biológicos, acompanhada por sincronização de áreas motoras não envolvidas na tarefa apenas na condição de mentalização e que a estimulação transcraniana por corrente contínua tem efeito sob toda a superfície do eletrodo e difere de acordo com a polaridade aplicada. O uso da estimulação transcraniana por corrente contínua combinada com tarefas de observação e mentalização pode conferir uma estratégia interessante de intervenção em distúrbios envolvendo comprometimento das habilidades motoras bem como comprometimento de habilidades de imitação e compreensão das ações do outro.

Le by-pass gastrique Roux-en-Y (BPG) est une chirurgie de l'obésité qui induit des améliorations spectaculaires de l'homéostasie glucidique indépendamment de la perte de poids. Un mécanisme proposé pour expliquer ces améliorations est une augmentation de la production intestinale de glucose (PIG) qui induit des effets bénéfiques sur l'organisme (satiété, amélioration de la sensibilité hépatique à l'insuline). Cette augmentation de la PIG, retrouvée chez la souris ayant subi un BPG simplifié, est également responsable des effets bénéfiques des régimes enrichis en protéines via l'inhibition des récepteurs mu-opioïdes (RMO) par les peptides. Nous avons donc testé l'hypothèse selon laquelle les effets bénéfiques du BPG dépendraient d'une inhibition des RMO par les protéines alimentaires et nous avons également testé le rôle causal de la PIG dans ces améliorations métaboliques. Pour cela, nous avons réalisé un by-pass duodéno-jéjunal (BDJ), ie un BPG sans restriction gastrique, chez des souris sauvages (WT), des souris invalidées pour le gène du RMO (MOR-/-) et des souris dépourvues de PIG (I-G6pc-/-). Chez les souris obèses, Le BDJ induit une forte perte de poids (–30%), en partie expliquée par une malabsorption lipidique, ainsi qu'une amélioration des paramètres glucidiques dépendante de cette perte de poids. Au contraire, chez la souris de poids normal, le BDJ n'induit ni perte de poids ni malabsorption mais améliore la tolérance au glucose. Les effets sont les mêmes chez les souris WT, MOR-/- et I-G6pc-/- ce qui montre que les récepteurs mu-opioïdes et la PIG ne semblent pas avoir de rôle causal dans les améliorations du métabolisme énergétique et glucidique après BDJ / Roux-en-Y gastric bypass procedure (GBP) is an obesity surgery that induces dramatic glucose homeostasis improvements independently of weight loss. A proposed mechanism to explain these glucose homeostasis improvements is an increase in intestinal glucose production (IGP) that induces beneficial effects on metabolism (satiety, improved liver insulin sensitivity). This increase in IGP is found in mice that have undergone a simplified GBP and is also responsible for the beneficial effects of protein-enriched diets through the inhibition of mu-opioid receptors (MOR) by alimentary peptides. We therefore hypothesized that the beneficial effects of GBP could depend on MOR inhibition by dietary proteins and we also tested the causal role of IGP in these metabolic improvements. For this purpose, we performed a duodenal-jejunal bypass surgery (DJB), ie GBP without gastric restriction, in wild-type mice (WT), in mice lacking MOR gene (MOR-/-) and in mice lacking IGP (IG6pc-/-). In obese mice, DJB induced a rapid and substantial weight loss (-30%), partly explained by fat malabsorption, and weight loss-dependent improvements of glucose homeostasis. In contrast, in the non-obese mice, DJB did not induce weight loss nor malabsorption but improved glucose tolerance. Effects were similar in WT, MOR-/- and I-G6pc-/- mice showing that mu-opioid receptors and IGP did not appear to have a causal role in glucose and energy metabolism improvements after DJB

In Sweden there are many ice halls and ice halls climate differ from the usual buildings' climate, because temperatures are lower indoors than outdoors during the summer months. This results in a higher vapor content outdoors compared with indoors during the course of the year. Moisture transport takes place from the outside towards the ice halls, which is contrary to what happens in a common building. During the critical period, the vapor transport direction is inward. When the hot air hits the cold surface of the wall structure, it leads to a risk of condensation in the wall that leads to moisture damage. Moisture damage can impair the wall structure and lead to unwanted consequences. The purpose of this study was to dimension a number of walls that meet climate conditions, which are done by dynamic humidity calculation in WUFI Pro 5.1 with adapted climate data and real climate data and then mold analysis in WUFI Bio. The aim of the bachelor thesis work was that the results from this study can then be used as a guide to the future building of ice skating walls. The results from WUFI Pro 5.1 and WUFI Bio have shown that a number of walls designed during this master thesis are judged to work as well as revealed how an ice hallway wall should not be constructed. The conclusion shows that climate conditions control the design of the wall structure. / I Sverige finns det många ishallar och ishallsklimatet skiljer sig från vanliga byggnaders klimat, detta på grund av att temperaturen är lägre inomhus än utomhus under sommarhalvåret. Detta resulterar i en högre ånghalt utomhus jämfört med inomhus under en del av året. Fukttransporten sker då utifrån och in mot ishallen, det vill säga tvärtemot vad som sker i en vanlig byggnad. Under den kritiska perioden är ångtransportsriktningen inåt. När den varma luften träffar den kalla ytan i väggkonstruktionen, medför det en risk för kondens i väggen som leder till fuktskador. Fuktskador kan försämra väggkonstruktionen och leda till oönskade konsekvenser som exempelvis mögelpåväxt och rötskador. Syftet med studien har varit att dimensionera ett antal väggar som klarar av klimatförutsättningarna, detta gjordes genom dynamisk fuktberäkning i WUFI Pro 5.1 med anpassade klimatdata samt verkliga klimatdata och sedan mögelanalys i WUFI Bio. Målet med examensarbetet var att resultaten från denna studie sedan kan komma att användas som en vägledning till framtida byggen av ishallsväggar. Resultaten från WUFI Pro 5.1 och WUFI Bio har visat att ett antal väggar som konstruerats under detta examensarbete bedöms att fungera samt kommit fram till hur en ishallsvägg inte skall konstrueras. Slutsatesen visar att klimatförutsättningarna styr dimensioneringen av väggkonstruktionen.

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From the start of their lives, infants and young children are surrounded by a tremendous amount of multimodal social information. One intriguing question in the study of early social cognition is how vital social information is detected and processed and how and when young infants begin to make sense of what they see and hear and learn to understand other people’s behavior. The overall aim of this thesis was to provide new insights to this exciting field. Investigating behavior and/or neural mechanisms in early life, the three different studies included in this thesis therefore strive to increase our understanding on perception and processing of social information. Study I used eye-tracking to examine infants´ observations of gaze in a third-party context. The results showed that 9-, 16- and 24-month-old infants differentiate between the body orientations of two individuals on the basis of static visual information. More particularly, they shift their gaze more often between them when the social partners face each other than when they are turned away from each other. Using ERP technique, Study II demonstrated that infants at the age of 4 to 5 months show signs of integrating visual and auditory information at a neural level. Further, direct gaze in combination with backwards-spoken words leads to earlier or enhanced neural processing in comparison to other gaze-word combinations. Study III, also an EEG investigation, found that children between 18 and 30 months of age show a desynchronization of the mu rhythm during both the observation and execution of object-directed actions. Also, the results suggest motor system activation when young children observe others’ mimed actions. To summarize, the findings reported in this thesis strengthen the idea that infants are sensitive to others´ gaze and that this may extend to third-party contexts. Also, gaze is processed together with other information, for instance words, even before infants are able to understand others’ vocabulary. Furthermore, the motor system in young children is active during both the observation and imitation of another person’s goal-directed actions. This is in line with findings in infants, children and adults, indicating that these processes are linked at neural level.

Le contrôle latéral trouve de nombreuses applications dans le domaine de l'assistance à la conduite. Un grand nombre d'accidents de la route sont provoqués par des mouvements de roulis et de lacet excessifs engendrant des sorties de route. De plus, ce type d'accidents se produisent généralement sur les routes nationales et départementales, et environ 30 % des incidents impliquent des véhicules seuls. L'objectif de cette thèse est de mettre en œuvre un correcteur qui soit en mesure d'assister le conducteur dans les situations de suivi de voies et de rejeter diverses perturbations auxquelles est soumis le véhicule telles que des vents latéraux ou un dévers de la route, tout en respectant les contraintes de confort, d'agrément de conduite et les limitations pratiques de l'actionneur de direction. La stratégie d'assistance retenue consiste à ajouter un couple à celui délivré par le conducteur grâce à l'intégration d'un moteur à courant continu sur la colonne de direction. Elle tient compte des trois composantes que sont le véhicule, la colonne de direction et le conducteur. Les travaux se sont donc focalisés sur les techniques de commande robuste qui utilisent les synthèses Hinfini et Hinfini-LPV. L'implantation de correcteurs d'ordre élevé n'est pas souhaitable donc l'élaboration d'un correcteur d'ordre réduit s'avère donc une solution adaptée. D'abord dans le cadre d'une synthèse de correcteur Hinfini à vitesse fixe, les spécifications sont respectées. Le dispositif d'assistance active confère au système en boucle fermée de bonnes propriétés de robustesse comme l'a montré la mu-analyse. Ensuite pour améliorer le domaine de stabilité du système commandé, un correcteur séquencé par la vitesse longitudinale est synthétisé. Il est plus performant et les résultats obtenus dans les mêmes conditions que le correcteur Hinfini fixe sont meilleurs.