This study is concerned with the measurable physiological changes in human beings in the presence of musical stimuli.

The main focus of the work is the design and construction of static excitation unit of asynchronous generator small hydro power plants with regard to the economic and technical demands. Description of the issue excitation asynchronous generators and possible technical solutions use asynchronous generators in island networks.

No description available.

sociological literature suggests that adult sports participation is occurring in a 'culture of risk' which glorifies pain, rationalises risk and promotes the practice of playing hurt (Messner, 1990; Nixon, 1992; Curry 1993; Pike, 2000; Roderick et aI, 2000, Safai, 2003; Howe, 2004; Young, 2004a; Liston et aI. 2006). Using this corpus of knowledge as a point of departure, this study directs attention towards young people's sporting risk encounters within the specific context of school sport. Guided by a process-sociological framework (Elias, 1978, 1991,2000 [1939]), it offers an insight into the ways in which young people interpret, experience and manage sporting risk and episodes of sporting pain and injury whilst at school. The research draws on data generated by 1,651 young people aged between ten and sixteen years old using a three-phase data collection programme. The programme incorporated self-report questionnaires, semi-structured interviews and group-based creative tasks and was conducted in six secondary schools located in "Churchill", a major English conurbation. The findings suggest that school sport worlds (re )produce two entwined, yet competing sets of beliefs, attitudes and practices related to sporting pain and injury and are best described as webs of risks and precaution and protectionism. Rather than adopting a more cautious approach to pain and injury the data indicates that this cluster of young people frequently play hurt, normalise injury and engage in forms of 'injury talk' that discredit episodes of sporting pain. In so doing, they may be placing their short and long-term physical, psychological, social and moral health in jeopardy. However, it is argued that this collection of sporting practices are highly valued by young people and are integral to the ways in which they assign and perform a range of dissecting and fluid embodied identities. Notwithstanding the potential for sporting risk encounters to engender damaging, disrupting and debilitating outcomes, the data also emphasises the potential for these experiences to act as important spaces in which young people are able to probe their bodily limits, develop corporeal knowledge and experience pleasurable emotions (Maguire, 199Ia). This thesis draws attention to the duality of sport and calls for a more reality-congruent approach to the sport-health-risk-youth nexus in the development of future (school) sport worlds.

The key to understanding vision is to acquire insight into the sensory coding of indi- vidual neurons. To this end, major advances were done over the past 50 years in fitting models to neural data to identify the mapping from sensory space to neural responses. Especially the advance of DNNs in neuroscience allowed for model fits with excellent predictive power. However, such advanced neural models are complex, and their poor in- terpretability has so far hindered deeper understanding of the principles of visual coding. To address this issue, a recent study proposed a method which identifies the stimulus that activates the neuron the most. However, the sensory coding of highly non-linear neurons, which are abundant already at the earliest stages of visual processing, is too complex for a single stimulus to sufficiently characterize it. A more robust way to char- acterize this coding is through identifying the input sub-space within which the neuron is activated identically - i.e. finding invariances of the neuron's sensory representation. In this thesis, a novel approach for finding such invariant stimuli is proposed. The proposed technique is based on a generator neural network, which maps Gaussian noise from latent space to a stimulus set which equally activates a given neuron. The method demonstrated the...

本研究使用美國、德國、英國股票指數期貨之日內交易資料，從報酬率中分離出連續波動度與跳躍項，再以MLE法估計Hawkes相互激勵過程之參數，衡量跨市場跳躍傳染現象。擴展文獻中僅兩市場的分析至三市場模型，更能從整體的角度解釋市場間的關係及跳躍傳染途徑。實證結果顯示，美國能直接影響其他市場，而其他市場反過來不易干涉美國，呈現非對稱影響效果。歐洲兩國能互相傳染，英國對德國的影響較大，也更有能力影響美國，稱英國為歐洲的影響輸出國，德國為歐洲的影響輸入國。

As vibrações em máquinas estão relacionadas à transferência de energia associada a dois efeitos devido ao atrito: a dissipação de energia e a auto-excitação. A dissipação de energia reduz e a auto-excitação aumenta a quantidade de energia de um sistema. Na dinâmica dos sistemas com atrito ocorrem os ciclos limite adere-desliza e movimentos caóticos que podem prejudicar o funcionamento das máquinas. Para o controle desses sistemas torna-se necessária uma estratégia de compensação do atrito. Em geral, não considera-se a influência da dinâmica do sistema oscilante sobre sua fonte de energia ou excitação externa. Em problemas práticos de engenharia, a representação mais realista dessa influência é denominada de sistema não-ideal ou de potência limitada (máquina não-ideal). Neste trabalho, considera-se a dinâmica e o controle de um sistema auto-excitado pelo atrito interagindo com sua fonte de energia. O comportamento dos sistemas ideal e não-ideal são investigados através de simulação numérica e apresentam-se resultados de uma estratégia de controle chaveado para posicionamento e para seguimento de trajetórias periódicas, com compensação robusta do atrito, e a análise de estabilidade pelo método de Lyapunov. / The vibrations of machines are related to energy transference associate to two effects due to the friction: the energy dissipation and the self-excitation. The energy dissipation decrease and the self-excitation increase the system energy quantity. In dynamics of systems with friction occurs the stick-slip limit cycles and chaotic motion that can damage the machine working. For the control of that systems become necessary an compensation strategy of friction. In generally, are not considering the dynamical influence of oscillating system undergo their energy source or external excitation. In engineering practice problems, the more realistic representation of this influence is called non-ideal system or limited power supply (non-ideal machine). This work considers the dynamics and control of a self-excited system due to the friction interacting with their energy source. The behavior of ideal and non-ideal systems are investigated through numerical simulation and results of a switching control strategy for positioning and periodic trajectories tracking, with robust compensation of friction, and the stability analysis by the Lyapunov method are presented.

As vibrações em máquinas estão relacionadas à transferência de energia associada a dois efeitos devido ao atrito: a dissipação de energia e a auto-excitação. A dissipação de energia reduz e a auto-excitação aumenta a quantidade de energia de um sistema. Na dinâmica dos sistemas com atrito ocorrem os ciclos limite adere-desliza e movimentos caóticos que podem prejudicar o funcionamento das máquinas. Para o controle desses sistemas torna-se necessária uma estratégia de compensação do atrito. Em geral, não considera-se a influência da dinâmica do sistema oscilante sobre sua fonte de energia ou excitação externa. Em problemas práticos de engenharia, a representação mais realista dessa influência é denominada de sistema não-ideal ou de potência limitada (máquina não-ideal). Neste trabalho, considera-se a dinâmica e o controle de um sistema auto-excitado pelo atrito interagindo com sua fonte de energia. O comportamento dos sistemas ideal e não-ideal são investigados através de simulação numérica e apresentam-se resultados de uma estratégia de controle chaveado para posicionamento e para seguimento de trajetórias periódicas, com compensação robusta do atrito, e a análise de estabilidade pelo método de Lyapunov. / The vibrations of machines are related to energy transference associate to two effects due to the friction: the energy dissipation and the self-excitation. The energy dissipation decrease and the self-excitation increase the system energy quantity. In dynamics of systems with friction occurs the stick-slip limit cycles and chaotic motion that can damage the machine working. For the control of that systems become necessary an compensation strategy of friction. In generally, are not considering the dynamical influence of oscillating system undergo their energy source or external excitation. In engineering practice problems, the more realistic representation of this influence is called non-ideal system or limited power supply (non-ideal machine). This work considers the dynamics and control of a self-excited system due to the friction interacting with their energy source. The behavior of ideal and non-ideal systems are investigated through numerical simulation and results of a switching control strategy for positioning and periodic trajectories tracking, with robust compensation of friction, and the stability analysis by the Lyapunov method are presented.

Le sujet de cette thèse concerne l’inférence statistique sur le processus de Mino que nous définissons comme un processus auto-excité de mémoire 1 dont l’intensité est de forme particulière. Nous donnons tout d’abord une description générale des processus auto-excités et des méthodes possibles pour estimer les paramètres de l’intensité de ces processus. Puis, nous considérons le cas particulier d’un processus auto-excité de mémoire 1 que l’on rencontre en traitement du signal et que nous avons dénommé : processus de Mino. Nous montrons que ce processus est un processus de renouvellement dont les interarrivées ont une distribution particulière que nous étudions en détails. Nous envisageons alors le problème de l’estimation des paramètres de l’intensité du processus de Mino en utilisant la méthode du maximum de vraisemblance. Nous résolvons les équations de vraisemblance en utilisant l’algorithme de Newton-Raphson. La méthode est appliquée à des données simulées. La convergence de l’algorithme de Newton-Raphson est démontrée, de même que l’existence et l’unicité des estimateurs. Nous terminons par la construction d’un test d’hypothèses qui permet de détecter si un processus ponctuel est auto-excité ou non / The subject of this PhD thesis is the statistical inference on Mino process that we define as a one-memory self-exciting point process which intensiy has a special form. We begin with a general description of self-exciting point processes and we present methods used to estimate the intensity parameters of these processes. We consider the special case of a one-memory self-exciting point process, used in signal processing. We call the process: the Mino process. This process can be interpreted as a renewal process which interarrival times that follow a special distribution that we study in details. In order to estimate the parameters of a Mino process intensity, we utilize the maximum likelihood method. We solve the likelihood equations with a Newton-Raphson algorithm. We show the efficiency of the method on simulated data. The convergence of the Newton-Raphson algorithm and, the existence and uniqueness of the maximun likelihood estimators are proved. Lastly, we construct a test of hypothesis to assess whether a point process is self-exciting or not.

Please read the abstract in the section front of this document / Thesis (PhD)--University of Pretoria, 2009. / Electrical, Electronic and Computer Engineering / Unrestricted