The present work proposes trial wave functions for the three-body problem in nuclear physics taking into account the group theoretical classification of the states given by Derrick and Blatt and by Verde. We start from the Schroedinger equation in the internal variables (the interparticle distances) obtained by Derrick from a summation over the matrix elements for kinetic energy and potential energy extended over all variables except the internal variables. An “equivalent" Schroedinger equation is set up using a potential due to Eckart. This equation has the same form as the original Schroedinger equation in the region outside the range of the nuclear forces. The variables in this equation can be separated in a hyperspherical coordinate system and the resulting separate equations can be solved. Then using a superposition principle the solutions of the original equation are expanded in terms of solutions to the "equivalent" equation. The Rayleigh-Ritz variational procedure is used to determine the coefficients of the expansions with a given potential. Because of the computational labor involved significant approximation is made in allowing only the leading terms in the angular variables to appear in the expansions while keeping a sufficient number of radial terms to insure convergence. The present functions with a radial variable R = [formula omitted] give less than 1/2 of the binding energy predicted by Blatt, Derrick and Lyness (1962) who used a radial variable R = r₁₂ + r₂₃ + r₃₁. This shows that our approximation with the former radial variable is indeed too crude to predict a reliable value for the binding energy and that more angular terms must be included in the expansions, at least for the preponderent symmetric S-state. Wave functions derived by the Rayleigh-Ritz variational principle are used to calculate cross sections for the reaction D(p, γ)He³. The electric dipole cross section depends very sensitively on the potential used to derive the wave function and a comparison with experimental data provides a test of the various model assumptions used to describe the nuclear interaction. A realistic potential must contain a tensor potential plus a hard core in the central potential. The tensor interaction couples the S and D states and is necessary to explain the quadrupole moment of He³ while the hard core produced the required mixed-symmetry S-state. The experimentally observed isotropic component of the gamma ray yield is attributed to a magnetic dipole transition between a continuum quartet S-state and the mixed-symmetry component of the ground state wave function. For a range of the variable parameter used in the calculation comparison with experiment requires a 5% admixture of the mixed-symmetry S-state in the ground state wave function. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Intensive field observations were conducted on a small British Columbia coastal stream for two years, supplemented by laboratory rearing and experiment. Stress was placed upon possible isolating mechanisms, as outlined by Mayr, that might serve to keep the marine stickleback (trachurus) and the freshwater form (leiurus)distinct. Lelurus permanently occupies the upper reaches of the stream; trachurus is anadromous, but enters the lower reaches to breed in "pure" freshwater. Between the breeding ground of the two, where some coexistence occurs, hybridization between leiurus and trachurus is extensive, but it is restricted to very narrow zones both in Little Campbell River near Vancouver and in certain Vancouver Island streams. Morphological analysis provides firm circumstantial evidence that hybrids are plentiful and that back-crossing occurs. Hybridization is confirmed by rearing experiments in the laboratory with crosses in all combinations. Most backcrossing is to the freshwater race and this is considered in detail. Behavioural experiments demonstrated the absence of mate preference; random mating occurs with respect to ethological isolation and hybrids perform courtship and parental care activities normally. Rearing hybrids uniformly and in all conbinations demonstrated the absence of genetic incompatibility, and vigorous offspring were produced. Fertile hybrids are abundant in the wild, but the sexes are seasonally isolated from one another. Behavoiral and genetic blocks to hybridization are absent, and thus there is no means to prevent hybridization where leiurus and trachurus come together. But evidence from the field and from preference tests demonstrated that ecological isolating mechanisms are very powerful barriers to hybridization. This is enforced to some extent by partial seasonal isolation, but early spawning migrants make a major contribution to hybridization in the Little Campbell River. Several factors probably operate to cause very narrow hybrid zones in stickle-backs, including a sedentary habit, habitat preference, and hybrid inferiority outside the hybrid zone. The latter could not be detected inside the hybrid zone. The complex of Isolating mechanisms found may well produce stable hybrid zones over long periods of time, and is discussed. Reinforcement of ecological isolating mechanisms probably occurs, and Moore's criticism of the spread of reinforced genotypes would not apply in this instance. Adaptation and consequent ecological isolating mechanisms are the cause of hybrid inferiority. In this instance pre and postmating mechanisms cannot be separated, for they go hand in hand. Geographic speciation is possible but problematical, and sympatric speciation cannot be excluded as a plausible explanation of divergence between sticklebacks as a result of disruptive selection. Distributional patterns of leiurus can best be explained by repeated and independent origins from trachurus. The two forms fulfill the species definition by Mayr and remain reproductively isolated, have well developed isolating mechanisms, and show considerable genetic divergence, much of it polygenic. There is no evidence that, introgression occurs, but a reverse cline in leiurus as well as very narrow hybrid zones demonstrates that selection severely restricts gene flow. Reproductive isolation between marine and freshwater forms seems to be widespread around the hemisphere. / Science, Faculty of / Zoology, Department of / Graduate

Avec l’augmentation des applications de sécurité, un sujet particulier a attiré plus d’attention que de nombreux autres domaines en reconnaissance de formes : la biométrie – la reconnaissance des personnes en fonction de leur physique et/ou de leurs traits comportementaux. Parmi ces traits, le visage se distingue par un compromis favorable entre accessibilité et fiabilité. Dans cette thèse, nous avons principalement travaillé sur une modalité relativement plus récente en reconnaissance du visage : la forme 3D. Plus avantageuse que son homologue en 2D, car intrinsèquement invariant aux changements d’illumination de pose, l’analyse 3D du visage se heurte encore à des défis majeurs tels que les déformations de surface du visage dues aux expressions ou occultations. En conséquence, une étude approfondie est effectuée sur ce sujet incluant le prétraitement des données 3D du visage, l’annotation automatique, la simulation d’altération et d’expressions en 3D, l’extraction de caractéristiques 3D et l’analyse locale de surface. / As the need and investment for security applications grow vastly, one particular topic has certainly been attracting higher attention than many other pattern recognition fields: biometrics – recognition of humans based on their physical and/or behavioral traits. Among those traits, face stands out with its favorable reconcilement between accessibility and reliability. In this doctoral dissertation, we principally investigate 3D shape which is a relatively more recent modality in face recognition. Being advantageous to its 2D counterpart for being intrinsically invariant to illumination and pose changes, 3D face recognition still encounters major challenges such as acquisition inadequacy or facial surface deformations due to expressions or occlusion. Bearing those in mind, a thorough study is carried out on this topic, including pre-processing of 3D facial data, automatic landmarking, facial expression and alteration simulations in 3D, 3D feature extraction and 3D regional surface analysis.

In 1984, T. Kobayashi gave a classification of the genus two 3-manifolds with a nontrivial torus decomposition. The intent of this study is to extend this classification to the genus two, torally bounded 3-manifolds with a separating non-trivial torus decomposition. These 3-manifolds are also known as the tunnel-1 generalized satellite knot exteriors. The main result of the study is a full decomposition of the exterior of a tunnel-1 satellite knot in an arbitrary 3-manifold. Several corollaries are drawn from this classification. First, Schubert's 1953 results regarding the existence and uniqueness of a core component for satellite knots in the 3-sphere is extended to tunnel-1 satellite knots in arbitrary 3-manifolds. Second, Morimoto and Sakuma's 1991 classification of tunnel-1 satellite knots in the 3-sphere is extended to a classification of the tunnel-1 satellite knots in lens spaces. Finally, for these knot exteriors, a result of Eudave-Muñoz in 1994 regarding the relative position of tunnels and decomposing tori is recovered.

The objective of this study is to observe the correlations between variable operating conditions and power quality parameters for a three-phase to single-phase cycloconverter. The cycloconverter is examined in its most straightforward form without additional output filters or elaborate control methods. Variable operating conditions include input frequency, output frequency, and resistive load size. The power quality parameters of interest are power factor, input current total harmonic distortion (THD), output voltage THD, and efficiency. The scope of the project includes analytical calculations, PSpice simulations, as well as a hardware implementation. The results show that output frequency has minimal effect on power quality. High input frequencies tend to yield less efficiency and larger loads yield higher efficiency. Total harmonic distortion undesirably peaks at a combination of low input frequency and high output frequency. Extrapolations can be made for the cycloconverter operating at different frequencies and loads based on the trends observed within the test matrix.

No description available.

At least four glacial stands occurred since 6.5 ka B.P. based on moraines located on the eastern flanks of the Three Sisters Volcanoes and the northern flanks of Broken Top Mountain in the Central Oregon Cascades. The youngest of these advances was the Little Ice Age (LIA) glaciation, which reached its maximum advance 150-200 yrs. B.P. and is defined by the large sharp crested and unvegetated moraines adjacent to the modern glaciers. In isolated locations less than 100 m downslope from these moraines, a second set of sparsely vegetated lateral moraines marks the Late-Neoglacial stand of the glaciers between 2.1 ± 0.4 and 7.7 ka B.P, A third set of Early-Neoglacial end moraines is 300-700 meters downslope of the modern glacier termini, and postdates 7.7 ka B.P. From SST temperature data (Barron et al., 2003) and a speleothem record (Vacco, 2003), we infer that this advance occurred between 4.5 and 6.5 ka B.P. Finally, the Fountonnor stand is marked by moraines 500-900 meters downslope of the modern glacier termini, and we infer these are latest Pleistocene or early Holocene. Modem equilibrium line altitudes (ELAs) at the Three Sisters and Broken Top are approximately 2500 - 2600 m. During the LIA, the ELAs were 40 - 180 m lower, requiring cooler mean summer temperatures by 0.7 - 1.0°C and winter snowfall to increase by 10 - 60 cm water equivalent. The average Early Neoglacial and Fountonnor ELAs were 130 - 300 m and 290 - 320 m lower than modem glaciers, respectively, requiring air temperatures to be 0.7 - 1.6°C and 1.5 - 1.7°C cooler during the summer and winter snowfall to be 40 - 100 cm water equivalent and 90 - 100 cm water equivalent greater.

This thesis discusses the development and application of theoretical and computational methods to study three-body processes. The main focus is on the calculation of three-body resonances and bound states. This broadly includes the study of Efimov states and resonances, three-body shape resonances, three-body Feshbach resonances, three-body pre-dissociated states in systems with a conical intersection, and the calculation of three-body recombination rate coefficients. The method was applied to a number of systems. A chapter of the thesis is dedicated to the related study of deriving correlation diagrams for three-body states before and after a three-body collision. More specifically, the thesis discusses the calculation of the H+H+H three-body recombination rate coefficient using the developed method. Additionally, we discuss a conceptually simple and effective diabatization procedure for the calculation of pre-dissociated vibrational states for a system with a conical intersection. We apply the method to H_3, where the quantum molecular dynamics are notoriously difficult and where non-adiabatic couplings are important, and a correct description of the geometric phase associated with the diabatic representation is crucial for an accurate representation of these couplings. With our approach, we were also able to calculate Efimov-type resonances. The calculations of bound states and resonances were performed by formulating the problem in hyperspherical coordinates, and obtaining three-body eigenstates and eigen-energies by applying the hyperspherical adiabatic separation and the slow variable discretization. We employed the complex absorbing potential to calculate resonance energies and lifetimes, and introduce an uniquely defined diabatization procedure to treat X_3 molecules with a conical intersection. The proposed approach is general enough to be applied to problems in nuclear, atomic, molecular and astrophysics.

Master of Science / Department of Electrical and Computer Engineering / Behrooz Mirafzal / Increasing energy demand, rising oil prices, and environmental concerns have forced attention to alternative energy sources that are environmentally friendly and independent of fossil fuels. Renewable energy sources (RES) have become an attractive alternative to the traditional energy sources for electric power generation. However, one of the main challenges of RES adaption arises when connecting RES to the electric grid. Voltage source inverters (VSIs), typically, connect RES to the electric grid. Similar to any engineering system, detailed dynamic models of the VSIs are needed for design and analysis purposes. However, due to the non-linearity of VSIs, development of dynamic models that can accurately describe their behavior is a complex task. In this thesis, a detailed averaged-state-space model of the two-level three-phase space vector pulse width modulation VSI and its companion LCL filter is derived. Because VSIs can operate under stand-alone and grid-tied modes, two models were derived for each case. In the derived models, the VSI modulation index m and phase angle ϕ are initially considered constant. In practice, however, these parameters are considered the main control parameters. To model these parameters as control inputs, small-signal models of the VSI under stand-alone and grid-tied modes were derived. To verify the accuracy of the developed large-signal and small-signal models, Matlab/Simulink simulations were carried out. The simulation results were compared against the models results. Moreover, the models were verified through lab experiments. The developed models can be used as design and analysis tools. In addition, the developed models can be used as fast and efficient simulation tools for system studies, when the modeling of switching transients is not needed. Nowadays, the number of VSIs connected to the electric grid is growing exponentially. The amount of time and computation needed to simulate VSIs using simulation software packages can be significantly decreased by the use of the developed models.

Specifically equipped and programmed robots are highly successful in controlled industrial environments such as automated production lines. For the transition of robots from such controlled uniform environments to unconstrained household environments with a large range of conditions and variations, a new paradigm is needed to prepare the robots for deployment. Robots need to be able to quickly adapt to their changing environments and learn on their own how to solve their tasks in novel situations. This dissertation focusses on the aspect of learning to predict the success of two-object means-end actions in a developmental way. E.g. the action of bringing one object into reach by pulling another, where the one object is on top of the other. Here it is the “on top” relation that affects the success of the action. Learning the preconditions for complex means-end actions via supervised learning can take several thousand training samples, which is impractical to generate, hence more rapid learning capabilities are necessary. Three contributions of this dissertation are used to solve the learning problem. 1. Inspired by infant psychology this dissertation investigates an approach to intrinsic motivation that is based on active learning, guiding the robot's exploration to create experience useful for improving classification performance. 2. This dissertation introduces histogram based 3D vision features that encode the relative spatial relations between surface points of object pairs, allowing a robot to reliably recognise the important spatial categories that affect means-end action outcomes. 3. Intrinsically encoded experience is extracted into symbolic category knowledge, encoding higher level abstract categories. These symbolic categories are used for knowledge transfer by using them to extend the state space of action precondition learning classifiers. Depending on the actions and their preconditions, the contributions of this dissertation enable a robot to achieve success prediction accuracies above 85% with ten training samples instead of approximately 1000 training samples that would otherwise be required. These results can be achieved when (a) the action preconditions can be easily identified from the used vision features or (b) the action preconditions to be learnt rest upon already existing knowledge, then it is possible to achieve these results by reusing the existing knowledge. This dissertation demonstrates, in simulation, an alternative to handcoding the knowledge required for a robot to interact with and manipulate objects in the environment. It shows that rapid learning, grounded in autonomous exploration, can be feasible if the necessary vision features are constructed and if existing knowledge is consistently reused.