Storage of freshwater in saline aquifers has a strategic importance in water deficit countries. The freshwater stored in these aquifers may be the only source of water available during times of crisis. Coupled simulation and optimization type groundwater management models have been developed that will achieve the optimal control of the storage of freshwater in a stagnant manner for constant density and variable density flows in hypothetical single- and multi-layered saline aquifers. The study is carried out in two stages. In the first stage, a transient model of five years is simulated that allows sufficient time for the freshwater mound to be created. In the second stage, an optimization model is formulated which minimizes the pumping/injection rates of a set of hydraulic gradient control wells subject to a set of constraints consisting of systems response equations, demand requirements, hydraulic gradient controls, pumping and injection limitations. The optimization models select which wells to be pumped and which ones to be injected and decide on their pumping/injection schedules to maintain the freshwater mound from migration. The results of the optimization models showed that the mound is successfully contained in its original location by controlling the hydraulic gradient via pumping/injection wells.

Variable digital filters (VDF) find many application areas in communication, audio, speech and image processing. This thesis analyzes design and implementation of FIR digital filters with variable frequency characteristics and introduces two design methods. The design and implementation of the proposed methods are realized on Matlab software program. Various filter design examples and comparisons are also outlilned. One of the major application areas of VDFs is software defined radio (SDR). The interpolation problem on sample rate converter (SRC) unit of the SDR is solved by using these filters. Realizations of VDFs on SRC are outlined and described. Simulations on Simulink and a specific hardware are examined.

In this thesis I examined the impacts of variable retention harvesting on residual tree mortality and natural regeneration of white spruce [Picea glauca (Moench (Voss)] in northern Alberta. The VR was done in four overstory canopy compositions (ranging from deciduous dominated to conifer dominated) and at six rates of canopy retention (2%, 10%, 20%, 50%, 75% and 100%). After 10 years there was 32.9 % mortality of aspen (Populus tremuloides Michx.) and 16.9 % mortality of spruce in the VR cuts. Mortality of individual trees was greater with low density of trees, in the conifer stands and for trees with short live crowns, which are large and trees near machine corridors. Natural regeneration of spruce was greatest with higher availability of seed trees (>30 ha-1) and on machine corridors, where stocking reached 74%. By contrast, stocking was 14% on retention strips, when seed tree density was 11 seed trees ha-1. / Forest Biology and Management

Modeling, simulation, and optimization play vital roles throughout the engineering design process; however, in many design disciplines the cost of simulation is high, and designers are faced with a tradeoff between the number of alternatives that can be evaluated and the accuracy with which they can be evaluated. In this thesis, a methodology is presented for using models of various levels of fidelity during the optimization process. The intent is to use inexpensive, low-fidelity models with limited accuracy to recognize poor design alternatives and reserve the high-fidelity, accurate, but also expensive models only to characterize the best alternatives. Specifically, by setting a user-defined performance threshold, the optimizer can explore the design space using a low-fidelity model by default, and switch to a higher fidelity model only if the performance threshold is attained. In this manner, the high fidelity model is used only to discern the best solution from the set of good solutions, so that computational resources are conserved until the optimizer is close to the solution. This makes the optimization process more efficient without sacrificing the quality of the solution. The method is illustrated by optimizing the trajectory of a hydraulic backhoe. To characterize the robustness and efficiency of the method, a design space exploration is performed using both the low and high fidelity models, and the optimization problem is solved multiple times using the variable fidelity framework.

In this dissertation, I consider linear, binary response correlated random coefficient (CRC) panel data models and a truncated CRC panel data model which are frequently used in economic analysis. I focus on the nonparametric identification and estimation of panel data models under unobserved heterogeneity which is captured by random coefficients and when these random coefficients are correlated with regressors. For the analysis of linear CRC models, I give the identification conditions for the average slopes of a linear CRC model with a general nonparametric correlation between regressors and random coefficients. I construct a sqrt(n) consistent estimator for the average slopes via varying coefficient regression. The identification of binary response panel data models with unobserved heterogeneity is difficult. I base identification conditions and estimation on the framework of the model with a special regressor, which is a major approach proposed by Lewbel (1998, 2000) to solve the heterogeneity and endogeneity problem in the binary response models. With the help of the additional information on the special regressor, I can transfer a binary response CRC model to a linear moment relation. I also construct a semiparametric estimator for the average slopes and derive the sqrt(n)-normality result. For the truncated CRC panel data model, I obtain the identification and estimation results based on the special regressor method which is used in Khan and Lewbel (2007). I construct a sqrt(n) consistent estimator for the population mean of the random coefficient. I also derive the asymptotic distribution of my estimator. Simulations are given to show the finite sample advantage of my estimators. Further, I use a linear CRC panel data model to reexamine the return from job training. The results show that my estimation method really makes a difference, and the estimated return of training by my method is 7 times as much as the one estimated without considering the correlation between the covariates and random coefficients. It shows that on average the rate of return of job training is 3.16% per 60 hours training.

Typescript. / Thesis (Ph.D.)--University of Hawaii at Manoa, 1985. / Bibliography: leaves 180-187. / Photocopy. / xiv, 187 leaves, bound ill., maps 29 cm

La problemática temporal habitual es la confrontación de la idea que intuitivamente se percibe frente a su medida cuantitativa por un reloj, ya que son perspectivas incompatibles porque la percepción de la dimensión temporal difiere de su medida según un eje de sucesión o escala fija, repetitiva y cuantitativa. A esta problemática se puede añadir la visión económica referente al valor del Tiempo, por cuanto que el mismo afecta o es necesario para los fenómenos y problemas económicos y financieros como la producción, la inversión, la planificación, el ahorro.El Tiempo en la Ciencia Económica queda oculto en la restricción temporal, sea siendo el Tiempo referente al período (duración o época) de análisis, sea en relación al análisis dinámico como factor que permite el orden y la síntesis matemática en una ley de evolución, sea como un bien económico valorable monetariamente. Según la naturaleza de la restricción temporal se distinguen las tres concepciones latentes en el Análisis Económico:1) El Tiempo lógico, que es homogéneo y reversible, que surge cuando se considera una restricción temporal cierta y estacionaria, que estaría vinculada a la descripción de un proceso estacionario y ergódico.2) El Tiempo causal, que es homogéneo e irreversible, que aparece con una restricción temporal cierta y dinámica, que estaría vinculada a la descripción de un proceso no estacionario, pero ergódico.3) El Tiempo Histórico, que es heterogéneo e irreversible, que se relaciona con una restricción temporal incierta y dinámica, que estaría vinculada a la descripción de un proceso no estacionario ni ergódico.A partir de esta modalidad temporal, se puede intentar superar el sesgo físico-matemático del análisis temporal financiero y proponer una noción temporal desde el punto de vista biológico, que denominamos Tiempo Histórico - Financiero. Dicha noción no simplifica la incertidumbre y complejidad observadas, introduciendo la dependencia histórica, y un futuro abierto y a priori imprevisible.De la comparativa teórica de la visión tradicional o física contra la visión propuesta o biológica del Tiempo aplicadas al análisis financiero, en cuanto a la forma, el valor y la influencia temporal, concluimos:a) La forma temporal se adecua al tipo de problema financiero a resolver, siendo en el caso de un problema de representación la más operativa el Tiempo lógico, en el caso de un problema de predicción el Tiempo causal y en el caso de un problema de explicación y comprensión el Tiempo histórico.b) El valor temporal bajo el supuesto de que compensa la distribución y uso eficiente de este factor económico se estima creíblemente bajo la forma de Tiempo lógico, pero bajo el supuesto de que compensa los frutos o la confianza en el acierto del Tiempo dedicado o requerido sería más adecuado la forma del Tiempo Histórico - Financiero.c) La influencia del Tiempo aplicada al proceso de decisión financiera se observa en el proceso de deliberación previo a toda elección, pudiéndose distinguir en este análisis dinámico en un problema financiero tres perspectivas temporales: el Tiempo contractual (manda la operación en la dinámica), el Tiempo de la especulación (mandan los resultados futuros en la dinámica) y el Tiempo de la inversión (mandan la continuidad y el riesgo en la dinámica).

The actual service loading histories of most engineering components are characterized by variable amplitudes and are sometimes rather complicated. The goal of this study was to estimate the fatigue life of nickel-chromium-molybdenum 30CrNiMo8HH steel alloy under axial and pure torsion variable amplitude loading (VAL) conditions. The investigation was directed at two primary factors that are believed to have an influence on fatigue life under such loading conditions: load sequence and mean stress. The experimental work for this research included two-step loading, non-zero mean strain loading, and VAL tests, the results of which were added to previously determined fully reversed strain-controlled fatigue data. The effect of load sequence on fatigue life was examined through the application of the commonly used linear damage accumulation rule along with the Manson and Marco–Starkey damage accumulation methods, the latter of which takes load sequence into account. Based on the two-step experimental results, both the Manson and Marco–Starkey methods were modified in order to eliminate the empirically determined constants normally required for these two methods. The effect of mean stress on fatigue life was investigated with the use of three life prediction models: Smith–Watson–Topper (SWT), Fatemi–Socie (FS), and Jahed–Varvani (JV). The cycles from the VAL histories were counted using a rainflow counting procedure that maintains the applied strain sequence, and a novel method was developed for the estimation of the total energy density required for the JV model. For two-step loading and for all three fatigue models employed, the modified damage accumulation methods provided superior fatigue life predictions. However, regardless of the damage accumulation method applied, the most satisfactory fatigue life correlation for VAL was obtained using the energy-based JV model.

The aim of this essay is to examine how people living in the Swedish countryside looked upon changes in the interiors through modernization in 1850-90. For the first time, there was an abundance of objects available in stores in the countryside that the majority of the population had money buy. Many novelties were introduced in the interior decoration of ordinary peoples´ homes. This study focuses on the introduction and use of wallpaper and is based on a questionnaire about wallpaper sent from the Nordiska museet, National museum of Culture history in Sweden, to people all over Sweden in 1948. 148 people responded to the questions about use and attitudes toward wallpaper during the second half of the 19th century. My theoretical perspective is cultural diffusion, the spread of cultural items, more specific the diffusion of innovations from larger to smaller places, often influenced by social elites, hierarchical diffusion, and between individuals, contagious diffusion. The analytical perspective used for the analysis is based on the concepts of basic and variable modernity, initiated by the historian Sven-Eric Liedman. Basic modernity describes the structural modernization in society as a whole within the fields of economy, technology and natural sciences. The variable modernity represents the different attitudes, likes and dislikes, opinions, viewpoints and cultural differences every individual possesses, the attitudes that decide how and if the modernity is received in each household. My intent has been to ascertain the factors that made production and distribution of relatively cheap wallpaper all over Sweden possible, pinpoint the most important driving forces for creating an interest in wallpaper within the villages, discover how wallpaper was introduced in the individual homes of farmers and how wallpaper was received. The use of wallpaper in the interiors has been examined in order to find out if, and how the modernization affected and was affected by the way people were living their lives within the home.

With perpetual strains on resources, road agencies need to develop network-level decision-making frameworks to ensure optimum resource allocation. This is especially true for incident management services and in particular variable message signs (VMS), which are relatively immature disciplines compared to traditional road engineering. The objective of incident management and VMS is to minimise the safety, efficiency, reliability and environmental impacts of incidents on the operations of the transport system. This may be achieved by informing travellers of the incidents so they can adapt their behaviour in a manner that reduces community impacts, such as lateness and the associated vehicle emissions, unreliability of travel times, as well as secondary accidents due to incidents. Generally, road authorities do carry out needs assessments, but qualitatively in many cases. Therefore, this masters research presents a framework that is systematic, quantitative and relatively easy to implement. In order to prioritise VMS infrastructure deployment, a risk management approach was taken that focuses on minimising the impacts on, and costs to the community. In the framework and case study conducted, safety, efficiency and reliability, and environmental impacts are quantified using an economic risk management approach to determine an overall risk score. This score can be used to rank road sections within the network, indicating the roads with the highest risk of incident network impacts and therefore the roads with the highest need for intervention. A cost-effectiveness based risk-reduction ranking can then be determined for each incident management treatment type, comparing the net risk with treatment to that without treatment, and dividing by the net present value of deployment. The two types of ranking, pure risk and cost-effectiveness based risk reduction, will help to minimise the network impacts on the community and optimise resource allocation.