Thesis (Ph. D.)--School of Aerospace Engineering, Georgia Institute of Technology, 2004. Directed by Dewey H. Hodges. / Vita. Includes bibliographical references (leaves 162-176).

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Στην παρούσα μελέτη, αφού ολοκληρώσαμε τις ήδη ευρεθείσες από άλλους ερευνητές, οικογένειες απλών συμμετρικών περιοδικών τροχιών, (δηλαδή τροχιών που είναι συμμετρικές ως προς το ισημερινό επίπεδο και το τέμνουν σε δυο σημεία), προχωρήσαμε ακόμη παραπέρα και για πρώτη φορά, υπολογίσαμε οικογένειες πολλαπλών συμμετρικών περιοδικών τροχιών, οι οποίες "διακλαδίζονται" από τις προηγούμενες, καθώς και οικογένειες ασύμμετρων περιοδικών τροχιών. Θα πρέπει ακόμη να σημειωθεί ότι υπολογίσαμε και τα ευσταθή τμήματα των οικογενειών αυτών, πράγμα που έχει ιδιαίτερη σημασία για τη μελέτη των ζωνών Van Allen. / -

Entry into elementary school marks the beginning of a crucial shift in the amount and quality of time that children spend with their peers (Coie & Dodge, 1988). For many 5-year olds, kindergarten provides the opportunity to encounter their first stable peer group. It is in the context of these interactions that children practice essential social skills, as well as develop a capacity to interact with others. For various reasons, however, many children have difficulty gaining acceptance into fundamental peer groups. For these children, the opportunities for peer interactions present in the early school years are limited and often characterized by a high degree of aggressive affect (Coie & Dodge, 1988). Although previous research has reliably identified the individual affective states characteristic of rejected children during a typical peer interaction (Newcomb, Bukowski, & Pattee, 1993), it should be kept in mind that these expressions are embedded within a larger peer context, which plays an important role in how these dynamic processes unfold in real time (O’Connell, Pepler, & Craig, 1999). The purpose of the present study was to explore the application of a dynamic systems (DS) technique, state space grids (SSG), to the study of kindergarten peer processes and their impact on long-term psychopathology. Participants were 267 kindergarten children from a single school serving a predominantly low socioeconomic neighbourhood. In order to examine the social dynamics of interacting triads, moment-to-moment changes in affect were documented. Parent and teacher ratings of child conduct problems were also obtained at four measurement points. Consistent with previous research, both controversial and rejected children were more likely to express aggressive affect. Differential effects across sociometric groups were also replicated for both externalizing and internalizing ratings, where rejected children were found to have significantly higher scores. Extending upon past research, the expression of particular triadic affective states were found to differ significantly across sociometric groups. Furthermore, specific triadic affective states were found to be related to the developmental trajectories of clinical outcomes. Overall, results of the present study extend previous findings on the expression of individual affective states through the application of DS principles and methodology. / Thesis (Master, Psychology) -- Queen's University, 2010-09-20 22:48:51.92

There is currently much UK government and industry interest towards the integration of complex computer-based systems, including those in the military domain. These systems can include both mission critical and safety critical applications, and therefore require the dependable communication of data. Current modular military systems requiring such performance guarantees are mostly based on parameters and system states fixed during design time, thus allowing a predictable estimate of performance. These systems can exhibit a limited degree of reconfiguration, but this is typically within the constraints of a predefined set of configurations. The ability to reconfigure systems more dynamically, could lead to further increased flexibility and adaptability, resulting in the better use of existing assets. Current software architecture models that are capable of providing this flexibility, however, tend to lack support for dependable performance. This thesis explores the benefits for the dependability of future dynamic systems, built on a publish/subscribe model, from using Quality of Service (QoS) methods to map application level data communication requirements to available network resources. Through this, original contributions to knowledge are created, including; the proposal of a QoS framework that specifies a way of defining flexible levels of QoS characteristics and their use in the negotiation of network resources, a simulation based evaluation of the QoS framework and specifically the choice of negotiation algorithm used, and a test-bed based feasibility study. Simulation experimentation conducted comparing different methods of QoS negotiation gives a clear indication that the use of the proposed QoS framework and flexible negotiation algorithm can provide a benefit in terms of system utility, resource utilisation, and system stability. The choice of negotiation algorithm has a particularly strong impact on these system properties. The cost of these benefits comes in terms of the processing power and execution time required to reach a decision on the acceptance of a subscriber. It is suggested, given this cost, that when computational resources are limited, a simpler priority based negotiation algorithm should be used. Where system resources are more abundant, however, the flexible negotiation algorithm proposed within the QoS framework can offer further benefits. Through the implementation of the QoS framework within an existing military avionics software architecture based emulator on a test-bed, both the technical challenges that will need to be overcome and, more importantly, the potential viability for the inclusion of the QoS framework have been demonstrated.

In this thesis, a novel robust estimation strategy for observing the system state variables of robotic manipulators with distributed flexibility is established. Motivation for the derived approach stems from the observation that lightweight, high speed, and large workspace robotic manipulators often suffer performance degradation because of inherent structural compliance. This flexibility often results in persistent residual vibration, which must be damped before useful work can resume. Inherent flexibility in robotic manipulators, then, increases cycle times and shortens the operational lives of the robots. Traditional compensation techniques, those which are commonly used for the control of rigid manipulators, can only approach a fraction of the open-loop system bandwidth without inducing significant excitation of the resonant dynamics. To improve the performance of these systems, the structural flexibility cannot simply be ignored, as it is when the links are significantly stiff and approximate rigid bodies. One thus needs a model to design a suitable compensator for the vibration, but any model developed to correct this problem will contain parametric error. And in the case of very lightly damped systems, like flexible robotic manipulators, this error can lead to instability of the control system for even small errors in system parameters. This work presents a systematic solution for the problem of robust state estimation for flexible manipulators in the presence of parametric modeling error. The solution includes: 1) a modeling strategy, 2) sensor selection and placement, and 3) a novel, multiple model estimator. Modeling of the FLASHMan flexible gantry manipulator is accomplished using a developed hybrid transfer matrix / assumed modes method (TMM/AMM) approach to determine an accurate low-order state space representation of the system dynamics. This model is utilized in a genetic algorithm optimization in determining the placement of MEMs accelerometers for robust estimation and observability of the system’s flexible state variables. The initial estimation method applied to the task of determining robust state estimates under conditions of parametric modeling error was of a sliding mode observer type. Evaluation of the method through analysis, simulations and experiments showed that the state estimates produced were inadequate. This led to the development of a novel, multiple model adaptive estimator. This estimator utilizes a bank of similarly designed sub-estimators and a selection algorithm to choose the true value from a given set of possible system parameter values as well as the correct state vector estimate. Simulation and experimental results are presented which demonstrate the applicability and effectiveness of the derived method for the task of state variable estimation for flexible robotic manipulators.

The impetus for this study grew from observations in clinical practice that many individuals survived all sorts of hardships with minimal distress, or with the ability to tolerate their distress, and move on with their lives in a positive manner. A review of the literature led to the conclusions that the research investigating resilience was making minimal inroads into understanding what made these people different, and that the richness of who they were was being lost in the scientific process. This dissatisfaction led to the decision to explore the construct from a phenomenological framework, and to try and discover the essential elements of resilience through analysis of the subjective experience of resilience. A qualitative study involving thirteen participants identified by their peers as resilient was undertaken and the underlying themes of their stories were analysed. This led to the development of a model of resilience that attempted to balance the need for parsimony with that of explanatory breadth, and which had the potential to tolerate the complexity and instability of the construct itself. The model developed identified three core elements that embraced the construct of resilience. These included the physiological capacity to be resilient, and from this basis the ability to be adaptive and the ability to maintain well-being emerge. Factors identified with these elements include individual reactivity to and recovery from adverse events, the ability to be effective and efficient in the management of adverse events, and the beliefs about the world and the self that promote well-being when exposed to adverse events. The model has a basis within neurobiology and is framed within the context of Dynamic Systems Theory. The theory itself is a culmination of clinical observations with what is known from within the current literature and the results of this study.

Utilizando-se entre a perna e a coxa os princípios da Teoria dos Sistemas Dinâmicos, foi estudada a coordenação intra-membros durante o andar em 16 sujeitos do sexo feminino. Os movimentos da perna e da coxa e suas relações foram analisados dinamicamente como sistemas acoplados de ciclo limite. Os sujeitos foram filmados lateralmente executando o andar em duas situações experimentais: normal e com uma sandália na perna direita na proporção de 5% do comprimento do segmento inferior. Os dados transformados em variáveis cinemáticas possibilitaram a análise da coordenação em termos de ângulos de fase, ponto de coordenação e fase relativa. Através dos dados angulares, foram testadas as propriedades dos osciladores não-lineares de ciclo limite. Os resultados indicaram que os segmentos apresentam uma órbita atrativa específica para cada um deles, que se mantém invariante ao longo das idades. Esta órbita atrativa representa a organização espaço-temporal do segmento durante o andar, servindo também para a visualização da quantidade de energia dissipada por parte de cada segmento. A análise dos ângulos de fase no momento da reversão, do ponto de coordenação e da fase relativa possibilitaram a identificação do treinamento mútuo e da estabilidade estrutural. / Based on the principles of the Theory of Dynamic Systems, 16 female subjects were studied as to their intra-limb coordination during walk. The movements of lower leg and thigh have been dynamically analised, - as well as their relation, - as limit-cycle coupled systems. Subjects were video-taped laterally, as they performed natural walking movements under two experimental situations: barefoot and with a sandal on the right foot with a thickness of 5% the length of the lower segment. Converted into kinematic variables, the data allowed the analysis of the coordination in terms of phase angle, point of coordination and relative coordination. The angular data made it possible to test the properties of the non-linear limit-cycle oscilator. Results pointed out that each segment involved in walking draws a specific attractive orbit, which is kept invariable throughout the ages. This attractive orbit represents the limb’s spacetemporal organization during walk, being, furthermore, an indication as to how much energy is being dissipated by each segment. The analysis of phase angles at the moment of limb reversion, the point of coordination and the relative phase made it possible to identify mutual training and structural stability.

Utilizando-se entre a perna e a coxa os princípios da Teoria dos Sistemas Dinâmicos, foi estudada a coordenação intra-membros durante o andar em 16 sujeitos do sexo feminino. Os movimentos da perna e da coxa e suas relações foram analisados dinamicamente como sistemas acoplados de ciclo limite. Os sujeitos foram filmados lateralmente executando o andar em duas situações experimentais: normal e com uma sandália na perna direita na proporção de 5% do comprimento do segmento inferior. Os dados transformados em variáveis cinemáticas possibilitaram a análise da coordenação em termos de ângulos de fase, ponto de coordenação e fase relativa. Através dos dados angulares, foram testadas as propriedades dos osciladores não-lineares de ciclo limite. Os resultados indicaram que os segmentos apresentam uma órbita atrativa específica para cada um deles, que se mantém invariante ao longo das idades. Esta órbita atrativa representa a organização espaço-temporal do segmento durante o andar, servindo também para a visualização da quantidade de energia dissipada por parte de cada segmento. A análise dos ângulos de fase no momento da reversão, do ponto de coordenação e da fase relativa possibilitaram a identificação do treinamento mútuo e da estabilidade estrutural. / Based on the principles of the Theory of Dynamic Systems, 16 female subjects were studied as to their intra-limb coordination during walk. The movements of lower leg and thigh have been dynamically analised, - as well as their relation, - as limit-cycle coupled systems. Subjects were video-taped laterally, as they performed natural walking movements under two experimental situations: barefoot and with a sandal on the right foot with a thickness of 5% the length of the lower segment. Converted into kinematic variables, the data allowed the analysis of the coordination in terms of phase angle, point of coordination and relative coordination. The angular data made it possible to test the properties of the non-linear limit-cycle oscilator. Results pointed out that each segment involved in walking draws a specific attractive orbit, which is kept invariable throughout the ages. This attractive orbit represents the limb’s spacetemporal organization during walk, being, furthermore, an indication as to how much energy is being dissipated by each segment. The analysis of phase angles at the moment of limb reversion, the point of coordination and the relative phase made it possible to identify mutual training and structural stability.

A introdução de uma nova expressão matemática para a entropia permite construir novos ensembles na Teoria das Matrizes Aleatórias. Neste trabalho, apresenta-se uma estrutura geral para construção de todos os possíveis ensemble. Portanto, os elementos das matrizes podem ser números reais, complexos ou mesmo quaternions. O principio da entropia (não-extensiva) máxima e o Cálculo Variacional são usados para realizar essa façanha. Esta tese está comprometida com a construção do Ensemble Ortogonal Generalizado, cujas matrizes aleatórias são simétricas e seus elementos são os números reais, especificamente. As distribuições das matrizes, as distribuições de um elemento da matriz e as estatísticas espectrais são obtidas, estudadas e os resultados apresentados. / The introduction of a new mathematical expression for the entropy allows the construction of new ensembles in Random Matrices Theory. A general structure is presented to the construction of all possible ensembles. Therefore the matrix\'s elements can be real numbers, complex numbers or even quaternions. The generalized of the maximum entropy (nonextensive) principle and the variational calculus are to use to realize this achievement. This thesis concerned with the construction of the Generalized Orthogonal Ensemble, whose random matrices are symetric and its elements are real numbers. The matrix distribuit ion, the distribuition of an element of the matrix and the spectrum statistical were to obtained, studied and the results presented.