Les travaux de cette thèse portent sur l'analyse de stabilité des systèmes dynamiques impulsionnels et la synthèse d'observateurs pour les systèmes dynamiques continus avec mesures discrètes.On considère que les mesures sont prises d'une façon aléatoire pour éviter la perte d'observabilité et on montre que la synthèse d'un observateur impulsionnel couplé avec un observateur classique continu via un gain est une solution pertinente pour reconstruire l'état continu du système et commander et stabiliser ces systèmes par un retour d'état basé sur ces observateurs. De plus, ce nouveau schéma d'observateur (impulsionnel couplé avec observateur classique continu) permet de reconstruire le vecteur de sortie même si les mesures prises ne vérifient pas les conditions du Shannon-Nyquist. Ensuite, un chapitre est dédié à la détection de mode actif et à la reconstruction de son état associé, ceci pour une classe de systèmes linéaires hybrides sous mesures clairsemées. La solution que nous avons apportée à ce problème est d'une part l'analyse d'observabilité des systèmes sous échantillonnage aléatoire et d'autre part la synthèse d'observateurs impulsionnels. Ici, la première approche est basée sur le concept d'échantillonnage compressif bien connu en théorie du traitementdu signal. Une synthèse d'observateurs impulsionnels a été présentée pourquelques cas particuliers.D'autre part, une nouvelle méthode de synthèse d'observateurs spécifique aux systèmes non linéaire continus avec mesures discrètes est également proposée. Cette méthode utilise la condition de Lipchitz pour la transformation d'un système non linéaire à un système linéaire à paramètres variants basée sur l'utilisation du théorème des accroissements finis afin de synthétiser des observateurs impulsionnels.Enfin, les observateurs proposés sont testés sur une application à la synchronisation de systèmes chaotiques dédiés à la communication sécurisée. / This thesis deals with the stability analysis of impulsive systems and the design of impulsive observers for systems under sparse measurements.The measures are sparse but random in order to avoid the loss of observability.Moreover, it is highlighted that the synthesis of an impulsive observer coupled with a classical continuous observer via an observer gain is an appropriate solution to reconstruct the continuous system state and to stabilize this system by state feedback based on these observers. In addition, this new scheme (impulsive observer coupled with classical observer) can reconstruct the output vector, even if the available measurement do not verify the Nyquist-Shannon conditions. Another part is dedicated to the detection of the active mode and to the estimation of the associated continuous state for a class of linear hybrid systems under sparse measurements. The solution we found to this problem is firstly the observability of systems under random sampling and secondly the design of an impulsive observer. Here, the first approach is based on the concept of compressive sensing theory well known in signal processing. The design of the impulsive observer is presented for some special classes of nonlinear systems.Moreover, a novel observer design method for continuous nonlinear systems withdiscrete measurements is proposed. This method uses the Lipchitz conditions andthe mean value theorem in order to transform the problem in a linear one.Finally, the proposed observer are tested on application to the synchronization of chaotic systems dedicated to the secure communications

Submitted by Fernando Souza (fernandoafsou@gmail.com) on 2017-08-11T14:47:59Z No. of bitstreams: 1 arquivototal.pdf: 3075980 bytes, checksum: 34017b499d4b0a096285315cb614b985 (MD5) / Made available in DSpace on 2017-08-11T14:47:59Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3075980 bytes, checksum: 34017b499d4b0a096285315cb614b985 (MD5) Previous issue date: 2015-12-04 / The urban violence has been increasing in almost Brazilian state and in order to face this threat, new technological tools are required by the police authorities in order to support their decisions on how and when the few available resources should be employed to combat criminality. In this context, this work presents an embedded computational tool that is suitable for detecting gun-shots automatically. To provide the necessary knowledge to understand the work, a brief description about impulsive sounds, re guns and the gun-shot characteristics are initially presented. Latter, a system based on modules is proposed to detect and recognize impulsive sound, which are characteristics of gun-shots. However, since the system contain several modules in this work we have focus only on two of them: the module for detecting impulsive sounds and the module for distinguish a gun-shot from any other impulsive sound. For the impulsive detection module, three well-known algorithms were analyzed on the same condition: the fourth derivative of the Root Median Square (RMS), the Conditional Median Filter (CMF) and the Variance Method (VM). The algorithms were tested based on four measured performance parameters: accuracy, precision, sensibility and speci city. And in order to determine the most e cient algorithm for detecting impulsive sounds, a cadence test with impulsive sounds, without or with additional noise (constant or increasing) was performed. After this analysis, the parameters employed on the CMF and VM method were tested in a wide range of con gurations to verify any possibility of optimization. Once this optimal method was determined, the classi cation module to recognize gun-shots started to be implemented. For this, two distinguish methods were compared, one based on the signal wrapped over the time and the other based on most relevant frequencies obtained from the Fourier transform. From the comparison between the two methods it was observed that the wrapped method provided 54% of accuracy in the classi cation of impulsive sounds, while with the frequency analysis this value was 72%. / A violência urbana vem crescendo anualmente em praticamente todos os estados brasileiros e para fazer face a essa amea ca, as autoridades policiais necessitam cada vez mais de ferramentas tecnológicas que os auxiliem na tomada de decisões sobre quando e como empregar os parcos recursos disponíveis a repressão do crime. Neste contexto, e apresentado nesse trabalho uma ferramenta computacional, passível de ser embarcada em dispositivos m oveis, que possibilita realizar a detecção e reconhecimento automático de disparos de armas de fogo. Para tanto, são descritos inicialmente os fundamentos básicos sobre sons impulsivos, armas de fogo e caracter sticas de disparos. Posteriormente, descreve-se uma proposta de um sistema modular de detecção e reconhecimento de disparos. No entanto, devido ao sistema conter diversos m odulos complexos, este trabalho teve foco em dois deles: o modulo de detecção de sons impulsivos e o modulo de classificação, que permite distinguir disparos de armas de fogo de outros sons impulsivos. Para o módulo de detecção de sons impulsivos foram analisados três algoritmos amplamente descritos na literatura: o algoritmo da quarta derivada da RMS, o da Conditional Median Filter (CMF) e o Método da Variância (VM). Os algoritmos foram testados com base nas medidas de desempenho da acurácia, precisão, sensibilidade e especificidade. E a para determinar o método mais e ciente, foram realizados testes de cadências, com sons impulsivos sem adição de ru do sonoro, com adição de ruído constante e com ruído variável. Ao final dessa anáise, os par^ametros preconizados na literatura para os m etodos CMF e VM foram alterados para uma verificação de possibilidade de otimização. De nido o algoritmo de detecção de impulso mais e ciente, iniciou-se o desenvolvimento do módulo de classificação. Para isso, foram propostas duas t ecnicas para o reconhecimento de disparos de armas de fogo, uma utilizando uma compara c~ao da envolt oria do som no dom nio do tempo e outra baseada na comparação de frequências dominantes obtidas por meio da transformada de Fourier. Numa comparação entre as duas técnicas observou-se que com a técnica da envoltória e poss vel identi car 54% dos sons impulsivos, enquanto que com a t ecnica baseada no dom nio da frequ^encia, este percentual foi de 72%.

The neurophysiological processes underlying the inhibition of impulsive responses have been studied extensively. While also the role of theta oscillations during response inhibition is well examined, the relevance of resting-state theta activity for inhibitory control processes is largely unknown. We test the hypothesis that there are specific relationships between resting-state theta activity and sensory/motor coding levels during response inhibition using EEG methods. We show that resting theta activity is specifically linked to the stimulus-related fraction of neurophysiological activity in specific time windows during motor inhibition. In contrast, concomitantly coded processes related to decision-making or response selection as well as the behavioral inhibition performance were not associated with resting theta activity. Even at the peak of task-related theta power, where task-related theta activity and resting theta activity differed the most, there was still predominantly a significant correlation between both types of theta activity. This suggests that aspects similar to resting dynamics are evident in the proportion of inhibition-related neurophysiological activity that reflects an “alarm” signal, whose function is to process and indicate the need for cognitive control. Thus, specific aspects of task-related theta power may build upon resting theta activity when cognitive control is necessary.

Background: Impulse buying is increasingly grown and it creates up to 80% of all purchases in certain low involvement product categories. In Sweden, a Swede can spend 20000SEK a year for impulse shopping in average. On the other hand, impulse buying is calculated to be strongly grown in the emerging markets such as Vietnam and Turkey. Due to the steady economic growth of 7% every year in Vietnam, it leads to a higher demand in shopping of the consumers. Similarly, Turkey’s economy is considered as one of the fastest growing economies in Europe and consequently leads to the increase of impulse buying behavior among the customers. Purpose: The purpose of the present study is to expand the understanding of the impulse buying behavior by looking further into the role of culture in cross-cultural contexts Hypothesis:   H1-There is a significant relationship between individualism-collectivism and impulse buying behavior. H2- There is a significant relationship between power distance and impulse buying behavior. H3- There is a significant relationship between uncertainty-avoidance and impulse buying behavior H4- There is a significant relationship between masculinity-femininity and impulse buying behavior Methodology: Three focus groups and seven interviews are served as the pre-study and a cross-cultural questionnaire is substantially conducted across three countries: Sweden, Turkey and Vietnam. Findings: Culture generates certain effects on impulse buying behavior and the influence is diverse across these countries. However, the findings also indicate that there could be other factors that could affect impulse buying behavior.

The original purpose of this study was to determine if Tegretol has an effect on the impulsive behavior exhibited by people with mental retardation. This was to be accomplished through a replication of the self-control choice procedures used by Ragotzy, Blakely, and Poling (1988). The procedure involved three stages. First, subjects chose between stimuli that provided either one or three edibles. Then the stimuli associated with the smaller and larger edibles were reversed. Following this, the procedure required the implementation of successively longer delays to the larger reinforcer. However, none of the subjects who participated was able to make the discriminations necessary to proceed, i.e., the subjects did not systematically select the stimulus associated with the larger magnitude edible choice. The identification and rectification of these errors in discrimination became the focus of this study. Various procedures were used to enhance discrimination, including fading, adjusting the magnitude of the edibles, and stimulus changes. None of these changes was successful in teaching the subjects the necessary discriminations.

Binge eating is a pervasive disordered eating behavior associated with numerous psychological and physical comorbidities. Preliminary research indicates that emotion regulation difficulties, behavioral impulsivity, and executive dysfunction may contribute to the onset and/or maintenance of these behaviors. However, few studies have utilized neuropsychological measures to examine this link, and the assessment of behavioral and cognitive emotion regulation strategies are limited in scope. The purpose of the current study was to gain a deeper understanding of the emotional, behavioral and cognitive processes associated with binge eating behavior. Greater clarity regarding how these factors relate to binge eating is critical to the development of effective treatment and prevention efforts. To address these aims, the current study examined the executive functioning, depression, behavioral impulsivity, distress tolerance, and emotion regulation strategies of 50 women engaging in weekly binge eating in the absence of compensatory behaviors; their outcomes were compared to 66 women with no history of binge eating. Hierarchical regression analyses revealed that groups did not significantly differ in executive functioning after controlling for depression, state anxiety, body mass, psychopharmaceutical use, and general intelligence; nonetheless, correlation analyses suggest that, among the binge eating group, individuals endorsing more frequent binge eating might have greater difficulties thinking flexibly or shifting attention. Secondary analyses indicated that individuals who binge eat are more depressed, are more likely to engage in impulsive behavior (but only when distressed), have more difficulties tolerating distress, are more likely to engage in rumination, self-blame, and catastrophizing, and less likely to focus on the positive. Although the current study is unable to determine whether these cognitive, emotional, and behavioral factors precede or follow binge eating episodes, outcomes have clinical implications. Specifically, programs focused on the prevention and treatment of binge eating should help individuals learn to better identify and tolerate difficult affective states and to utilize more adaptive means of coping. Outcomes also provide important directions for future research, including longitudinal designs to better understand the temporal associations of the current study’s variables, as well as suggestions to broaden and standardize neuropsychological assessment and scoring procedures to facilitate comparisons across studies.

L’objectif de cette thèse est d’étudier le comportement des codes LDPC dans un environnement où l’interférence générée par un réseau n’est pas de nature gaussienne mais présente un caractère impulsif. Un premier constat rapide montre que sans précaution, les performances de ces codes se dégradent très significativement. Nous étudions tout d’abord les différentes solutions possibles pour modéliser les bruits impulsifs. Dans le cas des interférences d’accès multiples qui apparaissent dans les réseaux ad hoc et les réseaux de capteurs, il nous semble approprié de choisir les distributions alpha-stables. Généralisation de la gaussienne, stables par convolution, elles peuvent être validées théoriquement dans plusieurs situations.Nous déterminons alors la capacité de l’environnement α-stable et montrons par une approche asymptotique que les codes LDPC dans cet environnement sont bons mais qu’une simple opération linéaire à l’entrée du décodeur ne permet pas d’obtenir de bonnes performances. Nous avons donc proposé différentes façons de calculer la vraisemblance en entrée du décodeur. L’approche optimale est très complexe à mettre en oeuvre. Nous avons étudié plusieurs approches différentes et en particulier le clipping dont nous avons cherché les paramètres optimaux. / The goal of this PhD is to study the performance of LDPC codes in an environment where interference, generated by the network, has not a Gaussian nature but presents an impulsive behavior.A rapid study shows that, if we do not take care, the codes’ performance significantly degrades.In a first step, we study different approaches for impulsive noise modeling. In the case of multiple access interference that disturb communications in ad hoc or sensor networks, the choice of alpha-stable distributions is appropriate. They generalize Gaussian distributions, are stable by convolution and can be theoretically justified in several contexts.We then determine the capacity if the α-stable environment and show using an asymptotic method that LDPC codes in such an environment are efficient but that a simple linear operation on the received samples at the decoder input does not allow to obtain the expected good performance. Consequently we propose several methods to obtain the likelihood ratio necessary at the decoder input. The optimal solution is highly complex to implement. We have studied several other approaches and especially the clipping for which we proposed several approaches to determine the optimal parameters.

Cognition (i.e. how individuals perceive, process and react to environmental cues) is fundamental to all animals’ life. Despite this, what explains variation in cognitive abilities is still mainly unclear. Environment is assumed to influences cognitive variation, but the mechanisms for this are still unknown. According to the social intelligence hypothesis, living in a group with a rich social environment, generate challenges that can enhance cognitive abilities. Impulsivity (to not be able to inhibit impulses), one aspect of cognition, may be influenced by the social environment, however this has not yet been experimentally tested. Impulsivity can complicate life, both for humans and animals. In humans, high levels of impulsivity and lack of self-control are associated with addictions and psychiatric disorders, thus is considered to be maladaptive. In animals, impulsivity correlates with stereotypies. To improve our understanding of impulsivity, I experimentally investigated how early social environment affects individual variation in impulsivity. To test this, red junglefowl chicks were used because their group living nature, and our accumulated knowledge on their cognition and behaviour. To manipulate the social environment, chicks either grew up in larger groups (with 17 individuals) or smaller groups (with 7 individuals). During the chicks’ first five weeks of life, three aspects of impulsivity were tested; impulsive action, persistence (in a detour reaching test) and routine formation (in a reversal learning test). Chicks that grew up in larger groups tended to perform less impulsive actions, while social environment did not explain variation in persistence. Chicks from larger groups had less strong routine formation compared to chicks raised in smaller groups. This partially supports the social intelligence hypothesis, and suggest that early social life can affect cognitive traits and explain individual variation in such.

Estudos comparando temperamento, caráter e impulsividade entre portadores de transtorno afetivo bipolar eutímicos e controles saudáveis têm mostrado escores mais elevados de busca de novidade, esquiva ao dano, autotranscendência e impulsividade, e escores mais baixos de autodirecionamento e cooperatividade entre os portadores de transtorno bipolar. Entretanto, não está claro se esses achados são resultado de um efeito cicatriz dos episódios ou representam marcadores de vulnerabilidade ao transtorno. O objetivo deste estudo foi avaliar traços de personalidade como prováveis marcadores de vulnerabilidade ao transtorno afetivo bipolar por meio da comparação de escores de temperamento, caráter e impulsividade entre portadores de transtorno afetivo bipolar, seus irmãos sem este transtorno e controles saudáveis. Foram avaliados 67 portadores eutímicos de transtorno afetivo bipolar tipo I, 67 irmãos e 70 controles saudáveis utilizando-se o Inventário de Temperamento e Caráter e a Escala de Impulsividade de Barratt. Foram considerados eutímicos os portadores de transtorno afetivo bipolar que apresentavam escores 7 na Escala de Avaliação de Depressão de Hamilton e na Escala de Avaliação de Mania de Young. As comparações das médias dos escores de impulsividade e das dimensões de temperamento e caráter entre os três grupos foram realizadas por meio de análise de variância. Testes post-hoc de Games-Howell ou Tukey (em função da homogeneidade de variância das variáveis dependentes) foram utilizados para análises posteriores par a par. O nível de significância alfa foi estabelecido em 5%. O resultados mostraram que portadores de transtorno afetivo bipolar eutímicos apresentaram, em relação aos controles saudáveis, escores significativamente mais elevados de busca de novidade, esquiva ao dano e autotranscendência, bem como de impulsividade motora, atencional e de não planejamento, e escores significativamente mais baixos de autodirecionamento e cooperatividade. Os irmãos não afetados por transtorno afetivo bipolar apresentaram, em relação aos controles saudáveis, escores significativamente mais elevados de esquiva ao dano e impulsividade motora, e escores significativamente mais baixos de autodirecionamento. O subgrupo de 32 irmãos sem qualquer diagnóstico psiquiátrico apresentou escores significativamente mais baixos de esquiva ao dano em relação aos controles. Esses resultados sugerem que escores elevados de esquiva ao dano e impulsividade motora e escores baixos de autodirecionamento podem representar marcadores de vulnerabilidade ao transtorno afetivo bipolar, sendo que a dimensão esquiva ao dano destaca-se por ter permanecido elevada mesmo entre os irmãos sem qualquer transtorno psiquiátrico. Esses dados podem contribuir para o avanço no conhecimento sobre os mecanismos neurobiológicos subjacentes ao transtorno afetivo bipolar, bem como para o desenvolvimento de estratégias de tratamento e prevenção desse transtorno / Recent studies have shown that euthymic patients with bipolar disorder present higher scores on impulsivity, novelty seeking, harm avoidance and selftranscendence and lower scores on self-directedness and cooperativeness than healthy controls. However it is unclear whether specific personality traits are vulnerability markers for bipolar disorder or represent a scarring effect of the affective episodes. The aim of this study was to compare temperament, character and impulsivity among patients with bipolar disorder, their unaffected siblings and healthy controls. We assessed 67 euthymic outpatients with bipolar disorder type I, 67 full siblings and 70 healthy controls using the Temperament and Character Inventory and the Barratt Impulsiveness Scale. Patients were euthymic if they present a Hamilton depression rating scale score and a Young mania rating scale score less than 8. Analysis of variance was used to compare mean scores of temperament, character and impulsivity among the three groups, and the Games- Howell test and the Tukey test were used as post-hoc tests for pairwise comparisons. The level of significance was set at 5%. Euthymic patients with bipolar disorder showed higher scores on impulsivity, novelty seeking, harm avoidance, and selftranscendence, and lower scores on self-directedness and cooperativeness than healthy controls. Their siblings without bipolar disorder diagnosis showed higher scores on harm avoidance and motor impulsivity and lower scores on selfdirectedness than healthy controls. A subset of 32 siblings who never have developed any psychiatric disorder during lifetime showed higher harm avoidance scores than healthy controls. Our results suggest that higher scores on harm avoidance and motor impulsivity, and lower scores no self-directedness may represent vulnerability markers for bipolar disorder. The harm avoidance dimension stands out since it remained higher even among siblings without any axis I psychiatric diagnosis. These data may contribute to further improve preventive strategies in subjects at high risk for bipolar disorder

As equações diferenciais impulsivas (EDIs) modelam fenômenos que são contínuos por partes, isto é, que evoluem continuamente mas em certos momentos sofrem mudanças abruptas (impulsos) consideradas instantâneas quando comparadas à duração total do processo. Surgem nas mais diversas áreas das ciências, como na modelagem de concentração de medicamentos no corpo humano e no impacto de propaganda nas vendas de uma empresa. O problema direto associado a uma EDI com instantes de impulsos pré-fixados consiste em, fornecidos a equação diferencial, a condição inicial, os momentos de impulso e os saltos, determinar a solução do problema. Por outro lado, as incógnitas dos problemas inversos associados são os saltos e/ou os momentos de impulso. Em geral, os problemas inversos não podem ser resolvidos diretamente por meio de técnicas convencionais. A abordagem funcional é uma alternativa baseada na minimização de um funcional de erro que confronta dados do fenômeno real e do modelo matemático. O mínimo global deste funcional corresponde à solução do problema inverso. O objetivo principal desta dissertação é investigar os problemas inversos de identificação dos parâmetros saltos e momentos de impulso. Buscamos descrever uma técnica que permita tratar de problemas inversos associados às EDIs de forma bem geral, que não utilize informações específicas da aplicação além das medidas no tempo inicial e final do processo. Para isso, desenvolvemos um programa computacional composto por uma função para solução numérica do problema direto usando o método de Runge-Kutta de quarta ordem, função esta que é chamada diversas vezes para cada resolução do problema direto com diferentes valores para as incógnitas; e pelo método de otimização Simulated Annealing que altera sistematicamente os valores das incógnitas. Os resultados mostram que resolver os problemas inversos que surgem das EDIs não é uma tarefa simples, que a técnica estudada é promissora e que pode ser aperfeiçoada / Impulsive differential equations (IDEs) model piecewise continuous phenomena, that is, that evolve continuously but at certain moments suffer abrupt changes (impulses) considered instantaneous when compared to the total duration of the process. They arise in several areas of science, such as the modeling of drug concentration in the human body and the impact of advertising on a companys sales. The direct problem associated with an IDE with impulses at fixed times consists of determining the solution to the problem, provided the differential equation, the initial condition, the moments of impulse and the jumps. On the other hand, the unknowns of the associated inverse problems are the jumps and/or the moments of impulse. In general, the inverse problems cannot be solved directly by conventional techniques. The functional approach is an alternative based on the minimization of an error functional that confronts data of the real phenomenon and the mathematical model. The global minimum of this functional corresponds to the solution of the inverse problem. The main objective of this dissertation is to investigate the inverse problems of jumps and moments of impulse parameters identification. We have attempted to describe a technique that allows treating of the inverse problems associated with IDEs in a general way, which does not use particular information of the application besides the measurements in the initial and final time of the process. For this, we developed a computer program composed by a function to solve the direct problem numerically using the fourth-order Runge-Kutta method, which is called several times for each resolution of the direct problem with different values for the unknowns; and by the Simulated Annealing optimization method which changes the values of the unknowns systematically. The results show that solving the inverse problems that arise from IDEs is not a simple task and that the technique studied is promising and can be improved