The main results of this thesis fall in to two areas, firstly quantum reference frames as a resource for quantum computations and secondly quantum algorithms. The results relating to quantum references consider their scaling with a requirements to perform measurements, operations and computations with a certain fidelity. For the case of a directional frame, the central question considered is of how many operations or measurements can be performed with it before its fidelity falls below some threshold. This is found to scale as the square of the size of the reference frame under for a range of physically interesting cases. To prove that result a new general form for any rotationally invariant map. This could have many applications is comparing and classifying rotationally invariant behaviour of quantum systems. Phase references are also considered for the case of performing quantum computations under an energy conservation law. The restriction that the expected energy be conserved for large quantum computations is shown to be manageable in many different potential architectures. In the case of completing computations is an energy conserving subspace, the requirements for ancillas are sublinear in the number of qubits, and even in a circuit model implementation, the errors due to phase reference imperfections are shown to not limit the apparent algorithmic improvements of quantum computing over classical computing. A quantum walk for the novel concept of two entangled walkers is proposed and analyzed. A modest improvement is found in the scaling of the expected separation of the walkers over the separable case. It illustrates the potential for making use of particle statistic behaviour in algorithms. Lastly, the relation between discrete and continuous time models of quantum computing is explored through the analysis of a new algorithm for simulating the Hamiltonian behaviour of a black box unitary operation. The scaling of the number of calls to the unitary required to obtain a simulation correct to within a parameter ϵ is found, as is a case where the efficiency of the algorithm is superior to directly applying the unitary repeatedly. Applications of the algorithm are considered.

The main results of this thesis fall in to two areas, firstly quantum reference frames as a resource for quantum computations and secondly quantum algorithms. The results relating to quantum references consider their scaling with a requirements to perform measurements, operations and computations with a certain fidelity. For the case of a directional frame, the central question considered is of how many operations or measurements can be performed with it before its fidelity falls below some threshold. This is found to scale as the square of the size of the reference frame under for a range of physically interesting cases. To prove that result a new general form for any rotationally invariant map. This could have many applications is comparing and classifying rotationally invariant behaviour of quantum systems. Phase references are also considered for the case of performing quantum computations under an energy conservation law. The restriction that the expected energy be conserved for large quantum computations is shown to be manageable in many different potential architectures. In the case of completing computations is an energy conserving subspace, the requirements for ancillas are sublinear in the number of qubits, and even in a circuit model implementation, the errors due to phase reference imperfections are shown to not limit the apparent algorithmic improvements of quantum computing over classical computing. A quantum walk for the novel concept of two entangled walkers is proposed and analyzed. A modest improvement is found in the scaling of the expected separation of the walkers over the separable case. It illustrates the potential for making use of particle statistic behaviour in algorithms. Lastly, the relation between discrete and continuous time models of quantum computing is explored through the analysis of a new algorithm for simulating the Hamiltonian behaviour of a black box unitary operation. The scaling of the number of calls to the unitary required to obtain a simulation correct to within a parameter ϵ is found, as is a case where the efficiency of the algorithm is superior to directly applying the unitary repeatedly. Applications of the algorithm are considered.

No description available.

This thesis investigates a set of non-classical visual receptive field properties observed in the primate brain. Two main phenomena were explored. The first phenomenon was neurons with head-centered visual receptive fields, in which a neuron responds maximally to a visual stimulus in the same head-centered location across all eye positions. The second phenomenon was perisaccadic receptive field dynamics, which involves a range of experimentally observed response behaviours of an eye-centered neuron associated with the advent of a saccade that relocates the neuron's receptive field. For each of these two phenomena, a hypothesis was proposed for how a neural circuit with a suitable initial architecture and synaptic learning rules could, when subjected to visually-guided training, develop the receptive field properties in question. Corresponding neural network models were first trained as hypothesized, and subsequently tested in conditions similar to experimental tasks used to interrogate the physiology of the relevant primate neural circuits. The behaviour of the models was compared to neurophysiological observations as a metric for their explanatory power. In both cases the neural network models were in broad agreement with experimental observations, and the operation of these models was studied to shed light on the neural processing behind these neural phenomena in the brain.

The choice of reference frames used in simulations is typically fixed in dynamic models based on modeling decisions made early during their development, restricting model fidelity, numerical accuracy and integration into large-scale simulations. Individual simulation components typically need to model the transformations between multiple reference frames in order to interact with other components, resulting in additional development effort, time and cost. This dissertation describes the methods for defining and managing different reference frames in a simulation, thereby creating a shared simulation environment that can provide reference frame transformations, comprising of kinematics and rotations, to all simulation components through a Reference Frame Manager. Simulation components can use this Reference Frame Manager to handle all kinematics and rotations when interacting with components using different reference frames, improving the interoperability of simulation components, especially in parallel and distributed simulation, while reducing their development time, effort and cost. The Reference Frame Manager also facilitates the development of Generic Dynamic Models that encapsulate the core service of dynamic model, enabling the rapid development of dynamic models that can be reused and reconfigured for different simulation scenarios and requirements. The Reference Frame Manager can also be used to introduce Intermediate Frames that bound the magnitudes of vehicle states, reducing roundoff error and improving numerical accuracy.

Thesis (Ph. D.)--Miami University, Dept. of Psychology, 2009. / Title from second page of PDF document. Includes bibliographical references (p. 53-59).

A critical function of the human visual system is to parse objects from the larger context of the environment, allowing for the identification of, and potential interaction with, those objects. The use of contextual information allows us to rapidly locate, identify, and interact with objects that appear in the environment. Contextual information can help specify an object's location within the environment (allocentric encoding) or with respect to the observer (egocentric encoding). Understanding how contextual information influences perceptual organization, and the neural systems that process a complex scene, is critical in understanding how contextual information assists in parsing local information from background. In the real world, relying on context is typically beneficial, as most objects occur in circumscribed environments. However, there are circumstances in which context can harm performance. In the case of visual illusions, relying on the context can bias observers' perceptions and cause significant motor errors. Studying the illusory conditions under which perceptual/motor functions are "fooled", or breakdown, can provide valuable information about how the brain computes allocentric and egocentric frames of reference. The following studies examine how attentional (Chapters II & III) manipulations of visuospatial context affect components of observers' egocentric reference frames (e.g., perceived vertical or subjective midline) and how neural manipulations (Chapter IV) can modulate observers' reliance on contextual information. In Chapter II, the role of attentional control settings on contextual processing is examined. Chapter III addresses the question of how visuospatial shifts of attention interact with an egocentric frame of reference. Finally, Chapter IV examines the functional role of superior parietal cortex in the processing of egocentric contextual information.

We conducted three experiments to better understand how mothers structure their input to young children for finding hidden objects and how young children use this input to guide their searches. We examined the reference frames and spatial terms mothers use to communicate with their 2.5-, 3.0-, and 3.5-year-old children about location by asking mothers to verbally disambiguate a target hiding container from an identical non-target hiding container for their child. We varied the relative proximity of the target and non-target containers to a landmark and to the mother and child. The target and non-target containers were on opposite sides of the landmark in Experiment 1 and on the same side of the landmark in Experiments 2 and 3. The absolute distance of the containers from the landmark was increased in Experiment 3, while the relative distance of the containers to the landmark and to the mother and child remained the same. In all of the experiments, mothers' reference frame use was governed by the relative proximity of the target and non-target containers to the landmark and themselves. Older children followed directions more successfully than did younger children. The Discussion focuses on how the age of the child and the characteristics of the task shape maternal spatial communication.

O objetivo principal deste trabalho é o desenvolvimento de controladores robustos baseados no princípio do modelo interno, em referenciais síncrono e estacionário, para aplicação ao estágio de saída de uma fonte ininterrupta de energia (UPS) a fim de minimizar a distorção na tensão de saída causada pela conexão de cargas não lineares balanceadas e desbalanceadas. A formulação em referencial estacionário (abc) é realizada através da aplicação de controladores com múltiplos modos ressonantes, a fim de se estabelecer erro nulo ao seguimento de referência senoidal e rejeição de distúrbios na tensão de saída devido às correntes com elevado conteúdo harmônico drenadas pelas cargas. Além disso, o controle é formulado em referencial síncrono (dq0) utilizando controladores Proporcional-Integral (PI) convencionais muito difundidos na maioria das aplicações comerciais de UPS. O projeto de ambos controladores é realizado utilizando uma metodologia de controle robusto com realimentação de estados, onde os parâmetros dos controladores são determinados através da resolução de um problema de otimização convexa sujeito a um conjunto de restrições na forma de desigualdades matriciais lineares (LMI). Uma análise comparativa de desempenho é realizada entre controladores com um modo ressonante (sintonizado na fundamental) e o PI em dq0, pois apresentam estruturas funcionalmente equivalentes sob a ótica do princípio do modelo interno aplicada a seus respectivos referenciais. Além do mais, demonstra-se a melhoria no desempenho com o uso dos controladores múltiplo ressonantes em referencial estacionário onde escolhe-se as frequências de ressonância de cada modo de maneira a suprimir os efeitos de harmônicas específicas na tensão de saída da UPS. A análise comparativa entre os controladores propostos é realizada através de simulações numéricas, utilizando os procedimentos de ensaio dinâmico e estático e as exigências estabelecidas pela norma internacional IEC 62040-3. / The main objective of this work is the development of robust controllers based on the internalmodel principle, in synchronous and stationary frames, applied to the output stage of an uninterruptible power supply (UPS), in order to minimize the output voltage distortion caused by the connection of balanced and unbalanced nonlinear loads. The formulation in stationary abc-frame is accomplished through the aplication of a multiple resonant controller, so that, it is possible to achieve zero-error tracking of the sinusoidal reference and disturbances rejection on the output voltage due to the high amount of harmonic currents drained by the loads. Moreover, a controller in synchronous reference frame (dq0 axis) is formulated through the application of conventional Proportional-Integral (PI) controllers which are widely used in comercial UPS applications. The design of both controllers is formulated using a state-feedback robust controlmethod, in which the controller parameters are determined by solving a convex optimization problem subject to a set of LMI constraints. A comparative analysis on the performance of the single-mode resonant controller (tuned at the fundamental frequency) and the PI controller is performed, because these controllers are functionally equivalent in the sense of the internal model principle applied to their respective frames. Furthermore, the improvement in performance is demostrated with the use of multiple resonant controllers in stationary abc-frame where the resonance frequencies are chosen to suppress the effects of a specific harmonic in the UPS output voltage. The comparative analysis of the proposed controllers is performed through numerical simulations, making use of the dynamical and steady-state test methods and performance requirements defined by the IEC 62040-3 international stardard.

O objetivo principal deste trabalho é o desenvolvimento de controladores robustos baseados no princípio do modelo interno, em referenciais síncrono e estacionário, para aplicação ao estágio de saída de uma fonte ininterrupta de energia (UPS) a fim de minimizar a distorção na tensão de saída causada pela conexão de cargas não lineares balanceadas e desbalanceadas. A formulação em referencial estacionário (abc) é realizada através da aplicação de controladores com múltiplos modos ressonantes, a fim de se estabelecer erro nulo ao seguimento de referência senoidal e rejeição de distúrbios na tensão de saída devido às correntes com elevado conteúdo harmônico drenadas pelas cargas. Além disso, o controle é formulado em referencial síncrono (dq0) utilizando controladores Proporcional-Integral (PI) convencionais muito difundidos na maioria das aplicações comerciais de UPS. O projeto de ambos controladores é realizado utilizando uma metodologia de controle robusto com realimentação de estados, onde os parâmetros dos controladores são determinados através da resolução de um problema de otimização convexa sujeito a um conjunto de restrições na forma de desigualdades matriciais lineares (LMI). Uma análise comparativa de desempenho é realizada entre controladores com um modo ressonante (sintonizado na fundamental) e o PI em dq0, pois apresentam estruturas funcionalmente equivalentes sob a ótica do princípio do modelo interno aplicada a seus respectivos referenciais. Além do mais, demonstra-se a melhoria no desempenho com o uso dos controladores múltiplo ressonantes em referencial estacionário onde escolhe-se as frequências de ressonância de cada modo de maneira a suprimir os efeitos de harmônicas específicas na tensão de saída da UPS. A análise comparativa entre os controladores propostos é realizada através de simulações numéricas, utilizando os procedimentos de ensaio dinâmico e estático e as exigências estabelecidas pela norma internacional IEC 62040-3. / The main objective of this work is the development of robust controllers based on the internalmodel principle, in synchronous and stationary frames, applied to the output stage of an uninterruptible power supply (UPS), in order to minimize the output voltage distortion caused by the connection of balanced and unbalanced nonlinear loads. The formulation in stationary abc-frame is accomplished through the aplication of a multiple resonant controller, so that, it is possible to achieve zero-error tracking of the sinusoidal reference and disturbances rejection on the output voltage due to the high amount of harmonic currents drained by the loads. Moreover, a controller in synchronous reference frame (dq0 axis) is formulated through the application of conventional Proportional-Integral (PI) controllers which are widely used in comercial UPS applications. The design of both controllers is formulated using a state-feedback robust controlmethod, in which the controller parameters are determined by solving a convex optimization problem subject to a set of LMI constraints. A comparative analysis on the performance of the single-mode resonant controller (tuned at the fundamental frequency) and the PI controller is performed, because these controllers are functionally equivalent in the sense of the internal model principle applied to their respective frames. Furthermore, the improvement in performance is demostrated with the use of multiple resonant controllers in stationary abc-frame where the resonance frequencies are chosen to suppress the effects of a specific harmonic in the UPS output voltage. The comparative analysis of the proposed controllers is performed through numerical simulations, making use of the dynamical and steady-state test methods and performance requirements defined by the IEC 62040-3 international stardard.