The problem of retention in public adult night school programs appears to be related to the socio-economic characteristics of participants and to the length and nature of the courses in which they enroll. Three hypotheses arising from this problem were tested in this study of participation patterns. The first of these stated that there are no statistically significant differences in certain socio-economic characteristics of participants who are enrolled in courses of different types or lengths. The second hypothesis tested was that there are no statistically significant differences in certain socio-economic characteristics between those participants who persist in attendance and those who drop out in the total program or in courses of different types and lengths. The third hypothesis stated that there are no significant differences in attendance patterns between the three types of courses or between courses of different lengths. The data used in this study were derived from 2,075 registration cards and ninety-eight completed attendance registers. Distributions for nine socio-economic characteristics of participants and dropouts were tested for statistically significant differences by chi square, and attendance patterns for courses of different types and lengths were compared using the critical ratio procedure. Four of the socio-economic characteristics of participants showed statistically significant differences at the .01 level in the distributions by course type and length while five did not. The significant characteristics included sex, age, marital status, and occupation. Thus in regard to these four characteristics, the Surrey program enrolled a different clientele for the three types of courses. Academic course participants tended to be young, single males in clerical, labourer, and transportation-communication occupational groups. General course registrants were the oldest group and consisted mainly of housewives. Vocational course participants occupied the median position between academic and general in each of the four significant characteristics. Twenty-eight percent of the registrants in the Surrey program were classified as dropouts. Three of the socio-economic characteristics tested showed statistically significant differences between persistent attenders and dropouts in the analysis by course type. These significant characteristics included age, marital status, and occupation. None of the characteristics tested were statistically significant at the .01 level in the distributions by course length. The highest number of dropouts occurred for young unmarried enrollees in academic courses while the lowest number occurred for housewives and those in the older age groups in general courses. An inconsistent downward trend was noted in average daily attendance for all courses. From a peak ADA of eighty-seven percent at the second session the attendance declined to thirty-eight percent at the forty-fifth session for a total loss of forty-nine percent. Short courses in the genera] interest category tended to maintain attendance at a higher level than did long courses in the academic and vocational categories. / Education, Faculty of / Educational Studies (EDST), Department of / Graduate

The distances travelled by non-credit evening class participants of two adult education institutions, the University of British Columbia Extension Department and the Vancouver School Board Night Schools, were studied by means of the analytic survey method. The participants in most of the non-credit courses offered on the campus by the Extension Department in one term were included in the study. A much smaller sample population of courses was selected from the three major night school centers operated by the Vancouver School Board. The participants of both institutions were grouped into two categories, Unique or Common. Unique participants were those who could obtain the course they attended at that one location only. Common participants were those who could have chosen alternative course locations. The distances travelled from place of residence to course location by Unique and Common Extension participants were compared as were the distances travelled by Unique and Common night school participants. The chi-square test of independence was used in the comparisons of the distributions of Unique and Common participants while the significance of the differences between the mean distances travelled and between the median distances travelled was determined by the use of critical ratios. The .01 level of confidence was the criterion used to determine the significance of differences. Distances travelled by Extension participants were found not to be influenced by alternative course locations in the same community when these alternatives were public school night school centers. Participants came from the whole of metropolitan Vancouver and distance did not seem to be a barrier within this area. Alternative course location in comparable centers in the community was found to influence the travel patterns of public school night school participants. Courses available at a single location attracted participants from the whole community whereas courses offered at three locations tended to attract participants more from the neighborhood of the center. Although there was some participation from the greater metropolitan area, the night schools tended more to serve the city alone than did the Extension Department. These findings suggest that the usefulness or necessity of additional Extension course locations in the metropolitan area is questionable. However, an increase in the number of public school evening course locations would seem likely to yield increased participation providing care was taken to avoid the competition which may result when new locations are placed too close to existing ones. / Education, Faculty of / Educational Studies (EDST), Department of / Graduate

The purpose of this study is to analyse the distances travelled to three urban night school centers in order to determine whether each serves separate areas or whether each serves larger, overlapping areas. The sample population consisted of 486 adults enrolled in twenty-two courses offered as part of the 1962-1963 program. Some of these selected courses were in subjects offered at all three centers; some courses were offered at two of the centers and the remainder were offered at only one center. It was thus possible to compare the centers while controlling for the number of centers offering the same subject matter. Distributions of distances travelled to each course and to each group of courses were prepared. The chi-square test of independence was used to compare the various distributions and the significance of the difference between mean distances travelled was used to provide additional comparisons. Maps were prepared illustrating the residences of participants and a correlation was made to determine the relationship between the distances travelled and the percentage of sessions attended by the participant. The results indicated that half of the 486 participants travelled less than 2.8 miles. More lived between one and two miles from the center they attended than in any other mile interval from the center. Only five percent of the participants travelled more than nine miles and less than one percent travelled more than fourteen miles. The statistical tests indicated that there was an association between the distance travelled and the center attended. It was found that when courses were offered at one center only, there was no statistical difference between the patterns of distance travelled to the three centers. Participants seemed to travel from throughout the city of Vancouver to attend, no matter which center offered the course. Women who attend courses designed for women only travel shorter distances than men who attend courses designed for men only. For courses offered at all three centers, adults travelled further to John Oliver Night School and to Technical Night School than to Kitsilano Night School. Travel distance does not inhibit the subsequent attendance of those who enroll. The opening of new night school centers during the past fifteen years was reviewed and it was found that a new center opened within two miles of a large well established center is unlikely to attract sufficient clientele to be economically successful. / Education, Faculty of / Educational Studies (EDST), Department of / Graduate

With distributed generation being introduced in the meshed distribution networks under increased loading conditions, maintaining the system voltage stability will become one of the major concerns. The conventional approach of repetitive power flow solutions fails to obtain the critical loading point as Jacobian becomes singular before maximum loading point. Continuation power flow methods, based on the predictor-corrector scheme, overcome this difficulty with the use of parameterization techniques. Continuation power flow tools, already developed for transmission systems, need to be extended to handle three phase unbalanced distribution systems. This research work contributes towards development of a robust and efficient three phase unbalanced continuation power flow tool for voltage stability assessment of shipboard power systems and terrestrial distribution systems. The developed continuation power flow method is based on adaptive step length control and pseudo arc length/local parameterization technique, which have been tested on several I test systems and a shipboard power system.

No description available.

No description available.

Let X be a smooth projective variety over C equipped with a C*-action whose fixed points are isolated. Let Y and Z be subvarieties of complementary dimentions in X which intersect properly. In this thesis we present an algorithm for computing the points of intersection between Y and Z based on homotopy continuation and the Bialynicki-Birula decompositions of X into locally closed invariant subsets. As an application we present a new solution to the inverse kinematic problem of a general six-revolute serial-link manipulator. / QC 20101108

Dans le cadre de la réduction des émissions polluantes et de la consommation des véhicules à moteur thermique, les constructeurs cherchent à diminuer la cylindrée et la vitesse de rotation des moteurs de chaines cinématiques. Ces évolutions conduisent, du fait du principe même du moteur à pistons, à une augmentation significative des irrégularités de rotation de celui-ci. Depuis quelques années, le système à pendule est apparu dans les groupes moto-propulseurs automobiles. Il agit à la manière d’un batteur, accordé sur l’ordre d’allumage du moteur thermique, et permet ainsi une réduction des vibrations. Cependant, les fortes non-linéarités intrinsèques aux pendules provoquent un désaccord du système à grande amplitude synonyme de perte de performances. Cette thèse a pour but d’améliorer la compréhension et le comportement du système en interaction avec la chaîne de traction automobile. En renfort des traditionnelles méthodes d’intégrations temporelles, le système non linéaire est résolu par la méthode asymptotique numérique couplée à la méthode de l’équilibrage harmonique. Une méthode originale de continuation d’antirésonance est également proposée ainsi que des règles de conception issues de développements analytiques. La validation par l’expérience montre une amélioration significative des performances du système. / In the context of the reduction of polluting emissions and fuel consumption of thermal engines of vehicles, automotive manufacturers try to reduce cylinder capacity and engine speed of rotation. These evolutions lead to significant increase of irregularities of rotation. The so-called centrifugal pendulum vibration absorber is a recent solution of mitigation of torsional vibrations in automotive powertrains. It acts as a mass damper tuned on the firing order of the engine and allows reduction of vibrations. However, strong non-linearities intrinsic to pendular systems cause a detuning of the device at large amplitude of motion resulting in a loss of performances. This thesis aims to improve the understanding and the behavior of the system in interaction with an automotive driveline. In support of classic time integration procedures, the nonlinear system is solved through the asymptotic numerical method coupled to the harmonic balance method. In addition, an original continuation of antiresonance method is proposed as well as some design rules derived from analytical developments. Experimental validation shows a significant enhancement of performances of the system.

Thesis (Ed. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Orientador: Dilson Amancio Alves / Banca: Sergio Azevedo de Oliveira / Banca: Francisco Carlos Vieira Malange / Banca: Luiz Carlos Pereira da Silva / Banca: Madson Cortes de Almeida / Resumo: Este trabalho analisa a utilização de técnicas de parametrização global para o fluxo de carga continuado. Essas técnicas são consideradas inadequadas para a obtenção da margem de carregamento de sistemas com problemas de estabilidade de tensão com características fortemente locais. Isto se deve ao fato de que no ponto de máximo carregamento a singularidade da matriz Jacobiana do método de parametrização global coincide com a da matriz Jacobiana do fluxo de carga. Nesses casos, a parametrização local é considerada como a única forma de se eliminar a singularidade. Entretanto, este trabalho mostra que a singularidade também pode ser eficientemente eliminada não só para estes sistemas, mas para qualquer outro, através de uma nova técnica de parametrização (global). A técnica utiliza a equação de uma reta que passa por um ponto no plano determinado pelas variáveis fator de carregamento e a somatória das magnitudes, ou dos ângulos, das tensões nodais de todas as barras do sistema, que são as variáveis comumente usadas pelas técnicas de parametrização global. Os resultados obtidos para diversos sistemas confirmam o aumento da eficiência dos métodos propostos e mostram sua viabilidade para aplicações no planejamento da operação nos atuais sistemas de gerenciamento de energia / Abstract: This work presents an analysis of the use of global parameterization techniques to the continuation power flow. Those techniques are considered inadequate for computation of the loading margin of power systems characterized by strong local static voltage stability. In such systems, at maximum loading point, the singularity of the Jacobian matrices of global parameterization techniques coincide with the one of the power flow Jacobian matrix. In those cases, the local parameterization is considered as the only way to overcome the singularity. However, this paper shows that this kind of singularity can be efficiently eliminated not only for these systems, but also for all others, by a new parameterization technique (global). This technique uses the addition of a line equation, which passes through a point in the plane determined by the sum of all the bus voltage magnitudes, or angles, and loading factor variables, that are variables commonly used by global parameterization techniques. The obtained results for several systems confirm the efficiency increased of the proposed methods and show its viability for applications in the operating planning in a modern energy management system / Doutor