In this study, we discuss AlGaN/GaN high electron-mobility heterostructs grown by metal organic chemical vapor deposition technique. We analyzed the samples by optical and magnetoelectrical experiments to probe the dependence of the piezoelectric effect on the structural difference. We hope our results may be useful for the design of nitride heterostructures. The E-beam evaporator operation manual given in this thesis may be useful for future users.

The construction of a liquid nitrogen-cooled ion mobility spectrometer coupled with time-of-flight mass spectrometry was implemented to demonstrate the ability to discriminate between electronic isomers. Ion mobility allows for the separation of ions based on differing cross-sections-to-charge ratio. This allows for the possible discrimination of species with same mass if the ions differ by cross-section. Time-offlight mass spectrometry was added to mass identify the separated peak for proper identification. A liquid nitrogen-cooled mobility cell was employed for a two-fold purpose. First, the low temperatures increase the peak resolution to aid in resolving the separated ions. This is necessary when isomers may have similar cross-sections. Second, low temperature shortens the mean free path and decreases the neutral buffer gas speeds allowing for more interactions between the ions and the drift gas. Kr2+ study was performed to verify instrument performance. The variable-temperature ion mobility spectrometer was utilized to separate the distonic and conventional ion forms of CH3OH, CH3F, and CH3NH2 and to discriminate between the keto and enol forms of the acetone radical cation. Density functional theory and ab initio calculations were employed to aid in proper identification of separating isomers. Monte Carlo integration tools were also developed to predict ion cross-section and resolution within a buffer gas.

An agent based-model of mobility of pastoralists was developed and applied to the semi-arid rangeland region extending from southern Ethiopia to northern Kenya. This model was used to investigate temporal adaptation of pastoralists to the spatial heterogeneity of their environment. This dissertation describes the development, structure, and corroboration process of the simulation model, Pastoral Livestock Movement Model (PLMMO). PLMMO is a spatially explicit, individual-based pastoralists-animal foraging and movement model. It simultaneously simulates the foraging and movement behavior of individual pastoralists and their livestock in a rangeland ecosystem. Pastoralists?? herd mobility patterns and other measures of movement were compared to data from field studies. Predictions of the model correspond to observed mobility patterns across seasons. The distances moved were found to be significantly correlated (r2 = 0.927 to 0.977, p<0.0001) to drought and non-drought climatic regimes. The PLMMO model therefore proved to be a useful tool for simulating general movement patterns of pastoralists relative to movement range sizes in the pastoral rangelands of southern Ethiopia and northern Kenya. We then used the PLMMO model to explore the impact of emerging changes in rangeland use in the study area. The ways in which pastoralists?? mobility patterns adapt to emerging challenges in the study area were explored by simulating the following four scenarios: 1) climate change with concomitant reduction in forage yield, 2) climate change with concomitant improvement and higher variability in forage yield, 3) increased livestock population densities and 4) improved access to water. The climate induced change scenario with increased and more variable forage production resulted in the shortest distances moved by pastoralists in comparison to all other scenarios. The total search distances under this scenario were only 20% of normal season distances. The improved water access scenario also returned a significant (p=0.017) drop in distances moved. There was, however, no significant impact on either increase in livestock numbers or reduction in available forage on mobility. We judged the agent-based model PLMMO developed here as a robust system for emulating pastoral mobility in the rangelands of eastern Africa and for exploring the consequences of climate change and adaptive management scenarios.

Pattern geometry plays a major role in determining oil recovery during waterflooding and enhanced oil recovery operations. Although simulation is an important tool for design and evaluation, the first step often involves rough calculations based upon areal sweep efficiencies of displacements in homogeneous, two-dimensional, scaled, physical models. These results are available as a function of the displacement pattern and the mobility ratio M. In this research I studied the effect of mobility ratios on five-spot and staggered waterflood patterns behavior for areal (2D) displacement in a reservoir that is homogeneous and isotropic containing no initial gas saturation. Simulation was performed using Eclipse 100 simulator. Simulation results are presented as graphs of areal sweep efficiency at breakthrough versus Craig mobility ratio for various staggered line drive aspect ratios. The main results of the study are presented in the form of a graph of areal sweep efficiency at breakthrough as a function of staggered line drive aspect ratio. This should enable engineers to utilize the results in a convenient manner.

In this paper, in order to reduce the location update cost in wireless mobile networks, we propose a cooperative location update scheme. The proposed scheme first discovers the statistical relation between mobile stations according to their history of location update and paging. In order to reduce the total cost of mobility management, we propose integrating the cooperative location update scheme with the concurrent search scheme. We use analytical results and simulation results to justify the usage of the proposed approach.

With the state-of-the-art IC technology, we can share a variety of digital content stored in our mobile devices via wireless communications. When requests for digital content arrive, base stations have to search for at least one copy of the digital content. We extend the concurrent search approach to efficiently location digital content. In addition, we propose the opportunistic concurrent search scheme in which a base station could use a single channel to page a number of mobile stations simultaneously. We use computer simulations to evaluate the performance and justify the usage of the proposed schemes.

The purpose of this thesis is to investigate the relationship between middle class and higher education through higher education policy. While the society gradually form the social class, each of them will try to obtain as much resource as they could. However, most of the resource is controlled by the upper class, which, due to the incapable of self-improvement, will eventually cause the conflict between different classes. In order to prevent the class struggle and conflict, and to maintain the social harmonious, the stable existence of Social Mobility is critical and important. And the easiest way for lower class to flow upward, is the education. After the declare end of the marshal law, the main purpose of education innovation in our country, is to expand the chance for people to receive higher education, raise the standard of knowledge, and increase the national competitiveness. However, while fixing all the old issue by the execution of the innovated policy, the upcoming problems have already risen. After the KMT re-achieve the presidency, the Exective Yuan shows the determination of restrain depression by the announcement of forming firm and solid middle class. If the indispensable way of social flow, education, is malfunctioning, the forming is incapable as well. It¡¦s obviously that the importance and requirement of education is raised, and the higher education is also widespread. However, does higher education in our country play it¡¦s role of promoting social flow? Does the consequence of successively education reform cause positive (or even negative) impact on the social mobility? These are the factors that this thesis wants to investigate.

Recent advances in wireless communication industry, radio- frequency circuits are developing fast. For power amplifiers, the active circuits are mainly composed of transistors where withstand high voltage and current. The excellent transistors characteristic result in good circuit performances. In the thesis, the modeling of InGaAs pseudomorphic high electron mobility transistor was provided by Win Semiconductor Corporation. The established small signal model contains extrinsic and intrinsic elements. The extrinsic elements are extracted by simple method without fitting process for long time. Then, the intrinsic elements are obtained by conventional matrix transformations. The each element of models is varied with different gate width area are also discussed. Finally, the nonlinear models are expanded upon the concept of small signal model. Due to some of intrinsic elements are significantly varied with bias, small signal models have not applied to nonlinear circuit simulations. For developing nonlinear models, the nonlinear elements characteristics are described by empirical fitting equations. The accuracy of models is achieved by comparing simulated and on wafer measurement results, including DC¡Bsmall signal and large signal power characteristics.

<p>Background: The most important resource of today’s companies is human resources. This has lead to a vast literature in the field of Human Resource Management, and within that are the fields of motivation and career management. Given the importance of technology intensive companies’ and the fact that engineers are increasingly dissatisfied and recognized as being difficult to manage a part of the literature have focused upon management of engineers. In this it is widely ac-cepted that engineers need special treatment, however, literature is not complete and a part which, up until now, has gained little attention is the one concerning career mobility.</p><p>Purpose: The purpose of this thesis is to identify the inducements and obstacles to the career mobility of engineers.</p><p>Frame of Reference: The first part of the theoretical framework covers motivation, in which the authors focus on McClelland’s Content Theory of Motivation, given its close connection to need for achievement, a central aspect in career mobility. The second part deals with previous research on management of engineers. Based on the Frame of Reference the authors construct the Career Mobility Model, which serve as a foundation for subsequent structure and interpretation.</p><p>Method: In order to fulfill the purpose of the thesis the authors chose a qualitative research method, and conducted twelve semis structured interviews. The results were then analyzed in the light of the theoretical framework.</p><p>Empirical Findings: The empirical findings consist of interviews with engineers of different ages, employment time and stages of their career. The interview results are organized based on the theoretical framework to aid forthcoming interpretation.</p><p>Analysis: In the analysis the authors apply the empirical findings on the Career Mobility Model, thus interpret the different obstacles and inducements to career mobility. The authors’ interpretations reveal a clear excess of obstacles compared to inducements at the company participating in the study.</p><p>Conclusions: By creating a challenging work situation and offering continuous education companies can create a good foundation for career mobility. However, without a uniform career management program combined with visible career routes and established communication channels a company will lack critical aspects of in-ducements to career mobility. Moreover, technical companies need to remember that the best specialist may not always be the best manager, given the many ob-stacles a specialist focused manager can induce.</p> / <p>Bakgrund: Den idag viktigaste resursen för företag är människor. Detta har lett till en omfattande litteratur inom ämnet Human Resource Management, och inom det återfinns ämnena motivation och karriär management. Givet betydelsen av teknologi intensiva företag och det faktum att missnöjet bland ingenjörer ökar samt att de är erkända som svåra att hantera har en del av litteraturen inom detta ämne fokuserat på hur man leder ingenjörer. Inom denna är det vida erkänt att ingenjörer behöver specialhantering, ändock är litteraturen inte fullständig och ett ämne, vilken det fram tills nu det givits lite uppmärksamhet åt, är karriärsrörlighet.</p><p>Syfte: Syftet med denna uppsats är att identifiera hinder och incitament till ingenjö-rers karriärsrörlighet.</p><p>Referensram: Den första delen av det teoretiska ramverket hanterar motivation, inom vilken författarna fokuserar på McClellands behovsteori, givet dess nära koppling till behovet av presentation, en central aspekt inom karriärs rörlighet. Den andra delen handlar om tidigare forskning vad gäller management av ingenjörer. Ba-serat på Referensramen skapar författarna Karriär Rörlighets Modellen vilken fungerar som en bas för kommande struktur och analys.</p><p>Metod: För att fullgöra syftet med uppsatsen valde författarna en kvalitativ undersökningsmetod, och genomförde tolv semistrukturerade intervjuer. Resultatet analyserade sen i ljuset av det teoretiska ramverket.</p><p>Resultat: De empiriska resultaten består av intervjuerna gjorda med ingenjörer i olika åldrar, med olika anställningslängd och i olika stadier av sin karriär. Intervju resultaten är organiserade baserat på det teoretiska ramverket för att underlätta inför den kommande analysen.</p><p>Analys: I analysen applicerar författarna den empiriska undersökningen på Karriär Rörlighets Modellen, vilket betyder att de analyserar hinder och incitament för karriärsrörlighet. Författarnas analys visar att det finns ett klart överskott av hinder jämfört med främjande faktorer på företaget i studien.</p><p>Slutsats: Genom att skapa en utmanande arbetssituation och erbjuda konstant utbildning kan företag skapa en bra bas för karriärsrörlighet. Likväl, utan ett övergripande program för karriärplanering kombinerat med synliga karriärvägar och etablerade kommunikationskanaler kommer företag att sakna kritiska aspekter som främjar karriärsrörlighet. Dessutom måste tekniska företag komma ihåg att den bästa specialisten inte alltid är den bästa ledaren, givet de många hinder en specialist fokuserad ledare kan skapa.</p>

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 85-93).