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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Regulation in Switched Bimodal Linear Systems

Wu, Zhizheng 28 September 2009 (has links)
In the past few decades, significant progress has been made in addressing control problems for a variety of engineering systems having smooth dynamics. In practice, one often encounters also non-smooth systems in various branches of science and engineering, such as for example mechanical systems subject to impact. Motivated by the read/write head flying height regulation problem in hard disk drives, where the close proximity of the read/write head to the disk surface results in intermittent contact between the two and a bimodal system behavior, this thesis studies the output regulation problem in switched bimodal linear systems against known and unknown exogenous input signals. The regulation problems in bimodal systems presented in this thesis are solved within sets of Q-parameterized controllers, in which the Q parameters are designed to yield internal stability and exact output regulation in the closed loop switched system. The proposed parameterized controllers are constructed mainly in two steps. The first step is based on constructing a switched observer-based state feedback central controller for the switched linear system. The second step involves augmenting the switched central controller with additional dynamics (i.e. Q parameter) to construct a parameterized set of switched controllers. Based on the proposed sets of Q-parameterized controllers, four main regulation problems are addressed and corresponding regulator synthesis algorithms are proposed. The first problem concerns regulation against known deterministic exogenous inputs, where no stability or structural constraints are imposed on the Q parameter. The second problem is similar to the first, except that the Q parameter is constrained to be a linear combination of basis functions. This structure of the Q parameter is considered in the rest of the thesis. The third problem involves regulation against exogenous inputs involving known deterministic components and unknown random components, and where the regulator is designed subject to an H2 performance constraint. The last problem involves the development of adaptive regulators against unknown sinusoidal exogenous inputs. The different regulator synthesis algorithms are developed based on solving sets of linear matrix inequalities or bilinear matrix inequalities. The last two proposed regulation methods are successfully evaluated on an experimental setup motivated by the flying height regulation problem in hard disk drives, and involving a mechanical system with switched dynamics.
412

Walk the line: Balancing conflicting goals through tension systems

Chua, Sook Ning January 2008 (has links)
Although our society esteems individuals who achieve it all, the 24-hour day and our limited resources means that attaining multiple goals is a difficult undertaking. This research draws upon Lewin’s theorizing on goal conflict and goal interruption to predict how individuals balance important conflicting goals. We predict that when an individual experiences goal conflict, the individual will prioritize his/her goals by moving towards one goal. Counter-intuitively however, we also hypothesize that this movement away from the competing goal will facilitate its pursuit, thus enabling goal balancing. We suggest that when the individual moves towards goal A, the competing goal B’s progress is interrupted. The psychological incompletion of goal B causes its state of tension to persist and consequently the individual feels the need to resume the goal. Accordingly, we expect affective and motivational consequences to this conflict-induced goal interruption. We found support for our hypotheses in 2 experiments that examined the conflict between academic and relationship goals. When individuals who are high in chronic relationship commitment experience goal conflict, they reported higher state relationship commitment (Chapter 2 and 3) and lower academic commitment (Chapter 3), relative to individuals who are low in chronic relationship commitment. However, in support of our conflict-induced goal interruption hypothesis, they also report lower partner affect (Chapter 2) and better performance in an academic-related task (Chapter 3).
413

Walk the line: Balancing conflicting goals through tension systems

Chua, Sook Ning January 2008 (has links)
Although our society esteems individuals who achieve it all, the 24-hour day and our limited resources means that attaining multiple goals is a difficult undertaking. This research draws upon Lewin’s theorizing on goal conflict and goal interruption to predict how individuals balance important conflicting goals. We predict that when an individual experiences goal conflict, the individual will prioritize his/her goals by moving towards one goal. Counter-intuitively however, we also hypothesize that this movement away from the competing goal will facilitate its pursuit, thus enabling goal balancing. We suggest that when the individual moves towards goal A, the competing goal B’s progress is interrupted. The psychological incompletion of goal B causes its state of tension to persist and consequently the individual feels the need to resume the goal. Accordingly, we expect affective and motivational consequences to this conflict-induced goal interruption. We found support for our hypotheses in 2 experiments that examined the conflict between academic and relationship goals. When individuals who are high in chronic relationship commitment experience goal conflict, they reported higher state relationship commitment (Chapter 2 and 3) and lower academic commitment (Chapter 3), relative to individuals who are low in chronic relationship commitment. However, in support of our conflict-induced goal interruption hypothesis, they also report lower partner affect (Chapter 2) and better performance in an academic-related task (Chapter 3).
414

Corruption, the unofficial economy and the provision of public goods in transition countries

Çule, Monika 13 January 2006 (has links)
For more than a decade, the countries of Central and Eastern Europe and the former Soviet Union have been attempting to transform their centrally planned economies into market economies. In some of these countries a considerably large unofficial economy has become a serious obstacle to economic growth and public finances. Studies by Johnson et al. (1997), Johnson et al. (1998), and Johnson et al. (2000) show that transition countries with large unofficial economies tend to have excessive regulations, high levels of taxation and high incidence of corruption. As well, bureaucratic corruption in tax and customs administration appears to be an important element in defining the underground economy in some transition countries. </p> <p>Given the potential impact of the unofficial economy on public finances and the provision of public goods, the purpose of this dissertation is to examine how corruption affects the unofficial economy in transition countries, with a particular focus on the unofficial economy that results from tax non-compliance. More specifically the study examines tax cheating as it relates to corruption in tax administration, to the business culture in the economy and to the tax-regulation policy-making process. The thesis looks at the feedback effects of decisions of different agents in the economy, and the implications of these decisions for the provision of public goods. </p> <p>The research is conducted along two lines. First, the thesis examines the nature and the extent of corruption in Albania, focusing particularly on the informal sector and corruption in customs and tax administrations. The thesis also examines the implications of the informal economy on the tax revenues available for the provision of public goods. Then the thesis examines the pattern of government spending in public education and transport infrastructure in Albania to reveal the priorities that these sectors are being given during the transition period. Second, the thesis develops a number of theoretical models to examine some of the issues raised in the analysis of Albania. The theoretical models provide a framework to examine the incentives for different agents in the economy to engage in tax cheating and corruption. More specifically, this section of the thesis examines: the feedback effects between the decision of tax inspectors to engage in corruption and firms' cheating activities; the firms' tax compliance as tax cheating and corruption are more accepted practices when they become increasingly widespread; how government affects the degree of cheating and corruption through auditing; and how corruption affects policy-makers' decisions to allocate the revenue obtained from tax collection between public education and infrastructure. </p> <p>Results from the theoretical models show that widespread bureaucratic corruption among tax inspectors can perpetuate an unofficial economy that in turn sustains these and other corrupt practices. In such situations, intense auditing and penalties serve as cheating deterrents only if cheating and engaging in corruption is very costly for both firms and tax inspectors. When cheating becomes cheaper as the size of the unofficial economy grows, a multiplier effect in the economy gives rise to Pareto-ranked multiple equilibria. In an economy with a widespread tolerance for corrupt tax enforcers, tax non-compliance and a low enforcement of penalties, the Pareto inferior (large unofficial economy and an under-provision of public goods) stable equilibrium can prevail. Changes that will move an economy from an inferior equilibrium to a superior equilibrium have a strong political dimension and are complex.</p> <p>Modeling the ways in which policy-makers affect the unofficial economy indicates that, due to the high cost of auditing, the government must allow for some cheating and corruption in order to maximize the revenues available for the provision of public goods. Only if a government views illicit activities as a "public bad", and is willing to eliminate these activities at any cost, will it choose to perform very intense auditing. The government's decision to allocate revenues between education and infrastructure depends on the returns generated by these public goods in the economy and on the private benefits from corruption. A government will allocate funds to education only if education generates relatively higher returns, and if the government favours at the margin the provision of public goods relative to private benefits from corruption. If at the margin the government favours the private benefits from corruption and cheating, then all revenues are allocated to infrastructure even though education generates higher relative returns in the economy. When infrastructure generates higher social returns in the economy, the government commits revenues to infrastructure either to provide the most beneficial public good, or to facilitate opportunities for corruption benefits. Overall the thesis shows that illicit activities (cheating, and political and bureaucratic corruption) can sustain each other regardless which actors in the economy (firms, enforcers, and politicians) undertake them.
415

The influence of state and trait energy on self-regulatory behaviour

Holmqvist, Maxine Elisabeth 12 January 2009 (has links)
Self-regulation is a highly adaptive process that enables goal-directed behaviour; however, individuals often fail to self-regulate successfully. Failures of self-regulation in the domain of health may be particularly harmful especially for those with chronic diseases. The Energy Model articulated by Baumeister and colleagues proposes that all acts of self-regulation rely on a single, finite energy resource. Thus, one possible explanation for self-regulation failure is insufficient energy. In the current research, four studies examine the relationship between the construct of energy, which can manifest in state or trait form, and self-regulatory success. Past research has demonstrated that individuals who perform two sequential tasks requiring self-regulation perform worse on the second task (the self-regulatory fatigue effect). The Energy Model proposes that this performance decrement can be explained by energy depletion. If this is true, then state energy should mediate the self-regulatory fatigue effect. A series of three experimental studies (studies 1-3) were designed to test this hypothesis. In Study 1, participants were randomly assigned to a gaze regulation task or to a no-regulation control group (as in Schmeichel et. al, 2003) before they watched a brief video clip. Following this first task, all participants worked on a second self-regulatory task (solving anagrams). Persistence and performance on this second task were the dependent measures and energy was measured before and after the initial video task. Contrary to the predictions of the Energy Model, the self-regulatory fatigue effect was not replicated in this study and so the mediating potential of energy could not be tested. However, ratings of task difficulty and effort suggested that individuals in the gaze regulation condition did not find this task to be very challenging. Accordingly, a second study was designed that added an additional level of self-regulatory demand by asking participants to rehearse a 7-digit number during the video clip (memory regulation). When this was crossed with the gaze regulation manipulation, four conditions were created: no regulation, gaze regulation only, memory regulation only and memory + gaze regulation. Study 2 then followed the same approximate procedure as Study 1, with individuals randomly assigned to one of the four conditions. The results of this study were consistent with Study 1 in that the self-regulatory fatigue effect was not replicated. However, the manipulation check suggested that some of the participants in the gaze regulation conditions may not have adhered to experimental instructions and the conditions may have differed in the degree to which they were enjoyable and interesting to participants. Accordingly, a third study used an eye-tracker to assess self-regulation during the video task and evaluated aspects of task engagement. Study 3 followed the same procedures as Study 2. Eye-tracker data verified significant differences between the groups in terms of self-regulation during the initial video task; however, there were no other significant between group differences. Taken together, these 3 studies indicate that the self-regulatory fatigue effect may be less robust than previous research would suggest. An unexpected finding was the high degree of variability in the energy measures, which implied that individual differences in energy may be important to consider. Accordingly, Study 4 prospectively examined the role of dispositional energy in the self-regulation of diet and exercise behaviour by testing whether energy moderated intention-behaviour concordance in a sample of individuals newly diagnosed with Type 2 diabetes. This study demonstrated that energy predicted future exercise behaviour in this sample and provided some preliminary support for the hypothesis that individuals with higher levels of dispositional energy may show more intention-behaviour concordance than those with lower levels of dispositional energy. Overall, these 4 studies provide some tentative support for the role of dispositional energy in the implementation of health behaviour, but do not support the Energy Models predictions regarding self-regulatory fatigue.
416

Investigations on the Mechanism of Allosteric Activtion of Rabbit Muscle Glycogen Phosphorylase b by AMP

Bigley, Andrew N. 2009 May 1900 (has links)
Much work has been carried out on glycogen phosphorylase over the last seventy years. Interest has persisted due not only to the usefulness of phosphorylase as a model system of allostery, but also due to the connection to the disease state in type II diabetes. The bulk of research consists of structural studies utilizing the wild-type enzyme from rabbit muscle. In this study we have employed linkage analysis in combination with structural perturbations via site-directed mutagenesis to test kinetic models of activation of phosphorylase b by AMP, and to examine the roles of the N-terminus, the acidic patch, ?-helix 1 and the 280?s loop in activation by AMP. Experiments have been carried out on purified glycogen phosphorylase b variants to determine the effects of perturbations in vitro. The kinetic models of activation by AMP are found to be a relatively accurate description of kinetic behavior of wild-type phosphorylase b, but are found to be technically incorrect with respect to the absolute requirements of two equivalents of AMP to be bound prior to catalysis. Phosphorylase b demonstrates activity in the absence of AMP, though only at high concentrations of phosphate, and a hybrid phosphorylase b with only a single functional AMP binding sight shows slight activation. The truncate ?2-17 shows weakened binding to AMP and phosphate in the apo enzyme, but maintains activation by AMP to an affinity similar to that of wild-type, indicating that the N-terminus is not required for activation by AMP, but has a role in establishing the affinity for both AMP and phosphate in the apo enzyme. Perturbations of the acidic patch indicate that interactions between the acidic patch and the N-terminus enhance the affinities in the apo enzyme, suggesting that the structures of the N-terminus at the acidic patch may represent an active form of the enzyme. ?-helix 1 is found to have a role in homotropic cooperativity in phosphorylase b, but not in heterotropic activation by AMP, while the 280?s loop is confirmed to have a role in the heterotropic coupling between AMP and phosphate. Based on the findings in this study an alternate structural model of activation by AMP involving ?-helix 8 is proposed.
417

Ratee Reactions: Negative Feedback as a Motivating Source

Kabins, Adam Howard 2010 December 1900 (has links)
The majority of empirical research on responses to negative feedback has focused on affective responses to negative feedback, which have largely been adverse. The purpose of this study was to examine how negative feedback enhances motivation. A key feature of this study is the conceptualization of motivation using Edward Deci and Richard Ryan’s self-determination theory. Self-determination theory proposes a continuum of motivation, based on one’s regulation, or contingency for performance. Goal orientation and social dominance orientation are proposed as two moderators of the negative feedback-regulation relationship. Two studies were conducted to examine the relationship between negative feedback and regulation. Study 1 used a survey-based instrument with a work sample after a performance appraisal was conducted (N = 221), and Study 2 took place in a psychology statistics undergraduate course (N = 156). Negative feedback yielded a decrease in obligated motivation in Study 1. Mastery prove goal orientation and performance prove goal orientation were consistent significant moderators of the negative feedback-regulation relationship, such that individuals with high levels of Mastery prove goal orientation increased their autonomous regulation at higher levels of negative feedback, while individuals with high levels of performance prove goal orientation decreased their autonomous regulation at higher levels of negative feedback. Implications for feedback delivery are discussed. This study contributes to the literature by being the first to examine the effects of negative feedback on all forms of regulation, and is the first to use goal orientation and social dominance orientation as moderators of the negative feedback – regulation relationship. Further, this study demonstrated the positive motivational effects of giving positive feedback as well as setting mastery prove based goals.
418

A Study on the Regulation for Convergence of Telecommunication and Cable TV Industries -Sampling European Union

Lin, Jia-Hung 12 June 2001 (has links)
THESIS ABSTRACT A Study on the Regulation for Convergence of Telecommunication and Cable TV Industries -Sampling European Union Audio, video and data are transferred by different channels traditionally. Therefore, there are diverse industries such as telecommunications, cable TV etc. But now the boundary between industries is ambiguous which is affected by technology development. This phenomenon makes it possible that competition exists between different industries. Moreover, it enhances the opportunities of convergence of industries and operation across industries. However conventional regulation defines regulatory scope according to products, services or technology. But changes of technology and market make conventional regulation unsuitable to current environment. Hence we should take a new regulation framework adapted to new market and development. European Union had involved these issues since 1980s and submitted a regulation framework suitable for future situation. Therefore, the researcher describes the roles and functions of relating authorities of E.U. and demonstrates the concrete implementations in response to convergence. Afterward, the researcher analyzes E.U. regulation by two perspectives: regulation authorities and regulation measures. From regulation authority perspective, the roles and attitudes about operation process are observed. From regulation measure perspective, these measures will be analyzed by goal, type and strategic level. Finally, the researcher tries to search for a general regulation framework for Taiwan¡¦s reference. In addition, after Taiwan¡¦s entrance to WTO, the process of negotiation between countries of E.U. could be a reference for Taiwan¡¦s authority to deal with international affairs.
419

In vivo regulation of [beta]-myosin heavy chain gene expression in skeletal muscle /

Vyas, Dharmesh R., January 2000 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 2000. / "December 2000." Typescript. Vita. Includes bibliographical references (leaves 190-220). Also available on the Internet.
420

Der Nucleus praeopticus medianus im Hypothalamus der Ratte als prä-integrative Struktur afferenter Signale zur Aufrechterhaltung des Salz- und Wasserhaushaltes sowie der Körperkerntemperatur

Weber, Tanja. January 2009 (has links) (PDF)
Zugl.: Giessen, Universiẗat, Diss., 2009.

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