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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.
161

The Social Life of Health Behaviors: The Political Economy and Cultural Context of Health Practices

Fletcher, Rebecca Adkins 01 June 2017 (has links)
Relocating health behaviors within a political-economic framework, this article utilizes health behavior and health insurance governance perspectives to showcase the complexities of cultural and economic factors (e.g., job lock, wage differentials, social location, and health insurance status) that influence choices in efforts to mitigate the financial burden of health risk. By exploring the financial links to health behaviors that emerged through ethnographic participant observation and semistructured interviews with community and union members of the United Steelworkers and Retail, Wholesale, and Department Store Union in a metropolitan Central Appalachian community in 2007–8, this article argues for expanding the health behaviors concept to include a broader array of actions individuals and families take to better their health and well-being in the context of neoliberal shifting of risk management to individuals through increased consumer market-based cost-sharing health insurance disincentives. In so doing, this article argues for the importance of social and political-economic context in health behaviors and in evaluating health policy, including the Affordable Care Act.
162

Computational fluid dynamics applications for the Lake Washington Ship Canal

Nielsen, Adam C. 01 May 2011 (has links)
The Seattle District wants to better manage the Ballard Locks and structures along the Lake Washington Ship Canal (LWSC) in a way that will maintain the environmental sustainability and biodiversity in the area. Due to strict salt water intrusion regulations in the LWSC, the Seattle District is working on upgrading their management practices such that they will resolve two inter-related problems. First, to improve the fish passage conditions for migrating salmon; and second, to learn how to better manage the salt wedge that forms and intrudes upstream. Based on the hydrodynamic and water quality results that are produced by this research, the Engineer Research and Development Center (ERDC) Portland Office will use their Eulerian-Lagrangian-Agent-Model (ELAM) to analyze fish patterns, looking for the most beneficial management schemes that assist salmon in migrating upstream. This research implemented CFD engineering techniques to help better understand the effectiveness of the hydraulic structures in the area, as well as come up with management practices that both mitigate the salt water intrusion from Puget Sound, and improve the migrating passages for salmon.
163

Intégration de systèmes hétérogènes en termes de niveaux de sécurité

Lemerre, Matthieu 05 October 2009 (has links) (PDF)
Cette thèse étudie les principes de mise en oeuvre pour l'exécution sur un même ordinateur, de tâches de niveaux de criticité différents, et dont certaines peuvent avoir des contraintes temps réel dur. Les difficultés pour réaliser ces objectifs forment trois catégories. Il faut d'abord prouver que les tâches disposeront d'assez de ressources pour s'exécuter; il doit être ainsi possible d'avoir des politiques d'allocations et d'ordonnancement sûres, prévisibles et simples. Il faut également apporter des garanties de sécurité pour s'assurer que les tâches critiques s'exécuteront correctement en présence de défaillances ou malveillances. Enfin, le système doit pouvoir être réutilisé dans une variété de situations. Cette thèse propose de s'attaquer au problème par la conception d'un système hautement sécurisé, extensible, et qui soit indépendant des politiques d'allocation de ressources. Cela est notamment accompli par le prêt de ressource, qui permet de décompter les ressources indépendamment des domaines de protection. Cette approche évite d'avoir à partitionner les ressources, ce qui simplifie le problème global de l'allocation et permet de ne pas gâcher de ressources. Les problèmes de type inversion de priorité, famine ou dénis de service sont supprimés à la racine. Nous démontrons la faisabilité de cette approche è l'aide d'un prototype, Anaxagoros. La démarche que nous proposons simplifie drastiquement l'allocation des ressources mais implique des contraintes dans l'écriture de services partagés (comme les pilotes de périphériques). Les principales difficultés consistent en des contraintes de synchronisation supplémentaires. Nous proposons des mécanismes originaux et efficaces pour résoudre les problèmes de concurrence et synchronisation, et une méthodologie générale pour faciliter l'écriture sécurisée de ces services partagés.
164

Contrôle longitudinal et caractérisation optique du détecteur Virgo

Kreckelbergh, Stephane 10 October 2005 (has links) (PDF)
Le détecteur Virgo est constitué d'un interféromètre de Michelson avec des cavités Fabry-Perot de 3 km de long dans les bras et utilise la technique de recyclage de puissance. Il a pour but la détection directe des ondes gravitationnelles émises par des sources astrophysiques. <br />Pour atteindre sa sensibilité, Virgo doit être emmené à son point de fonctionnement par des asservissements tant longitudinaux qu'angulaires. Pour cela, nous avons mis en place un algorithme de contrôle longitudinal ("lock") qui partant d'un interféromètre libre l'emmène à son point de fonctionnement. Pour arriver à ce résultat, nous utilisons la technique de Pound-Drever qui nous permet d'avoir un signal sensible à la variation de la position d'une cavité optique par rapport à la résonance. <br />Nous avons developpé deux algorithmes. Le premier s'inspire de celui utilisé par la collaboration LIGO. Nous arrivons au point de fonctionnement en contrôlant successivement les quatres longueurs caractéristiques de Virgo. L'application de cet algorithme sur l'instrument s'est soldé par un échec dont les causes sont liées aux différences entre Virgo et LIGO. Le deuxième algorithme nous permet de contrôler simultanément ces quatres longueurs en étant sur la mi frange de l'interféromètre de Michelson. Nous emmenons ensuite l'interféromètre en quelques minutes à son point de fonctionnement de manière déterministe. <br />Une autre partie de la thèse consiste en la mesure in situ des paramètres optiques nécessaires à la compréhension de l'instrument. Ceci nous a permis à la fois de faire accorder la simulation avec les données et de préparer l'algorithme d'acquisition du lock de Virgo. <br />Enfin, nous nous intéressons à l'impact de la technique d'Anderson utilisée pour le contrôle angulaire des miroirs sur le contrôle longitudinal des cavités optiques. Nous en montrons le mécanisme et évaluons son impact sur le lock de Virgo.
165

Effects of interference on carrier tracking in fading and symbol synchronization

Emad, Amin 11 1900 (has links)
Synchronization is a very important part of every digital communication receiver. While in bandpass coherent transmission, frequency and phase synchronization play a very important role in reliable transmission, symbol timing recovery is a necessary part of every baseband and bandpass coherent receiver. This dissertation deals with the problem of synchronization in the presence of fading and interference. First, the performance of an automatic frequency control loop is investigated using two parameters of average switching rate and mean time to loss of lock. These parameters are derived in closed-form or as integral-form formulas for different scenarios of modulated and unmodulated signals in different fading channels when there is one interference signal present at the input of the AFC. Then, the results are generalized to the noisy fading scenario and it is shown that in Rayleigh fading case, the performance of AFC becomes better when the desired signal is noisier. In the second part, the problem of symbol timing recovery is investigated in systems that are subject to intersymbol interference and non-data-aided maximum likelihood synchronizer is derived in these channels. Then, a new simple bound on the performance of synchronizers is derived and compared to the previously known lower bounds. It is shown that while this lower bound solves the shortcomings of the well known modified Cramer-Rao bound at small values of signal-to-noise-ratio, it is much easier to compute compared to another well known bound, the detection theory bound. / Communications
166

The economics of climate change and the change of climate in economics:the implications for climate policy of adopting an evolutionary perspective/Economie du changement climatique et changement de climat en économie: implications pour la politique climatique de l'adoption d'une perspective évolutionniste

Maréchal, Kevin 11 September 2009 (has links)
1. Contextual outline of the PhD Research Climate change is today often seen as one of the most challenging issue that our civilisation will have to face during the 21st century. This is especially so now that the most recent scientific data have led to the conclusion that the globally averaged net effect of human activities since 1750 has been one of warming (IPCC 2007, p. 5) and that continued greenhouse gas emissions at or above current rates would cause further warming (IPCC, 2007 p. 13). This unequivocal link between climate change and anthropogenic activities requires an urgent, world-wide shift towards a low carbon economy (STERN 2006 p. iv) and coordinated policies and measures to manage this transition. The climate issue is undoubtedly a typical policy question and as such, is considered amenable to economic scrutiny. Indeed, in today’s world economics is inevitable when it comes to arbitrages in the field of policy making. From the very beginning of international talks on climate change, up until the most recent discussions on a post-Kyoto international framework, economic arguments have turned out to be crucial elements of the analysis that shapes policy responses to the climate threat. This can be illustrated by the prominent role that economics has played in the different analyses produced by the Intergovernmental Panel on Climate Change (IPCC) to assess the impact of climate change on society. The starting point and the core idea of this PhD research is the long-held observation that the threat of climate change calls for a change of climate in economics. Borrowing from the jargon used in climate policy, adaptation measures could also usefully target the academic discipline of economics. Given that inherent characteristics of the climate problem (e.g. complexity, irreversibility, deep uncertainty, etc.) challenge core economic assumptions, mainstream economic theory does not appear as appropriately equipped to deal with this crucial issue. This makes that new assumptions and analyses are needed in economics in order to comprehend and respond to the problem of climate change. In parallel (and without environmental considerations being specifically the driving force to it), the mainstream model in economics has also long been (and still is) strongly criticised and disputed by numerous scholars - both from within and outside the field of economics. For the sake of functionality, these criticisms - whether they relate to theoretical inconsistencies or are empirically-based - can be subsumed as all challenging part of the Cartesian/Newtonian legacy of economics. This legacy can be shown to have led to a model imprinted with what could be called “mechanistic reductionism”. The mechanistic side refers to the Homo oeconomicus construct while reductionism refers to the quest for micro-foundations materialised with the representative agent hypothesis. These two hypotheses constitute, together with the conjecture of perfect markets, the building blocks of the framework of general equilibrium economics. Even though it is functional for the purpose of this work to present them separately, the flaws of economics in dealing with the specificities of the climate issue are not considered independent from the fundamental objections made to the theoretical framework of mainstream economics. The former only make the latter seem more pregnant while the current failure of traditional climate policies informed by mainstream economics render the need for complementary approaches more urgent. 2. Overview of the approach and its main insights for climate policy Starting from this observation, the main objective of this PhD is thus to assess the implications for climate policy that arise from adopting an alternative analytical economic framework. The stance is that the coupling of insights from the framework of evolutionary economics with the perspective of ecological economics provides a promising way forward both theoretically as well as on a more applied basis with respect to a better comprehension of the socioeconomic aspects related to the climate problem. As claimed in van den Bergh (2007, p. 521), ecological economics and evolutionary economics “share many characteristics and can be combined in a fruitful way" - which renders the coupling approach both legitimate and promising. The choice of an evolutionary line of thought initially stems from its core characteristic: given its focus on innovation and system change it provides a useful approach to start with for assessing and managing the needed transition towards a low carbon economy. Besides, its shift of focus towards a better understanding of economic dynamics together with its departure from the perfect rationality hypothesis renders evolutionary economics a suitable theoretical complement for designing environmental policies. The notions of path-dependence and lock-in can be seen as the core elements from this PhD research. They arise from adopting a framework which is founded on a different view of individual rationality and that allows for richer and more complex causalities to be accounted for. In a quest for surmounting the above-mentioned problem of reductionism, our framework builds on the idea of ‘multi-level selection’. This means that our analytical framework should be able to accommodate not only for upward but also for downward causation, without giving analytical priority to any level over the other. One crucial implication of such a framework is that the notion of circularity becomes the core dynamic, highlighting the importance of historicity, feedbacks and emergent properties. More precisely, the added value of the perspective adopted in this PhD research is that it highlights the role played by inertia and path-dependence. Obviously, it is essential to have a good understanding of the underlying causes of that inertia prior to devising on how to enforce a change. Providing a clear picture of the socio-economic processes at play in shaping socio-technical systems is thus a necessary first step in order to usefully complement policy-making in the field of energy and climate change. In providing an analytical basis for this important diagnosis to be performed, the use of the evolutionary framework sheds a new light on the transition towards low-carbon socio-technical systems. The objective is to suggest strategies that could prove efficient in triggering the needed transition such as it has been the case in past “lock-in” stories. Most notably, the evolutionary framework allows us to depict the presence of two sources of inertia (i.e at the levels of individuals through “habits” and at the level of socio-technical systems) that mutually reinforce each other in a path-dependent manner. Within the broad perspective on path dependence and lock-in, this PhD research has first sketched the implications for climate policy of applying the concept of ‘technological lock-in’ in a systemic perspective. We then investigated in more details the notion of habits. This is important as the ‘behavioural’ part of the lock-in process, although explicitly acknowledged in the pioneer work of Paul David (David, 1985, p. 336), has been neglected in most of subsequent analyses. Throughout this study, the notion of habits has been studied at both the theoretical and applied level of analysis as well as from an empirical perspective. As shown in the first chapters of the PhD, the advantage of our approach is that it can incorporate theories that so far have been presented opposite, partial and incomplete perspectives. For instance, it is shown that our evolutionary approach not only is able to provide explanation to some of the puzzling questions in economics (e.g. the problem of strong reciprocity displayed by individual in anonymous one-shot situations) but also is very helpful in bringing a complementary explanation with respect to the famous debate on the ‘no-regret’ emission reduction potential which agitates the experts of climate policy. An emission reduction potential is said to be "no regret" when the costs of implementing a measure are more than offset by the benefits it generates such as, for instance, reduced energy bills. In explaining why individuals do not spontaneously implement those highly profitable energy-efficient investments , it appears that most prior analyses have neglected the importance of non-economic obstacle. They are often referred to as “barriers” and partly relate to the ‘bounded rationality’ of economic agent. As developed in the different chapters of this PhD research, the framework of evolutionary economics is very useful in that it is able to provide a two-fold account (i.e. relying on both individual and socio-technical sources of inertia) of this limited rationality that prevent individuals to act as purely optimising agents. Bearing this context in mind, the concept of habits, as defined and developed in this study, is essential in analysing the determinants of energy consumption. Indeed, this concept sheds an insightful light on the puzzling question of why energy consumption keeps rising even though there is an evident increase of awareness and concern about energy-related environmental issues such as climate change. Indeed, if we subscribe to the idea that energy-consuming behaviours are often guided by habits and that deeply ingrained habits can become “counter-intentional”, it then follows that people may often display “locked-in” practices in their daily energy consumption behaviour. This hypothesis has been assessed in our empirical analysis whose results show how the presence of strong energy-consuming habitual practices can reduce the effectiveness of economic incentives such as energy subsidies. One additional delicate factor that appears crucial for our purpose is that habits are not fully conscious forms of behaviours. This makes that individuals do not really see habits as a problem given that it is viewed as easily changed. In sum, based on our evolutionary account of the situation, it follows that, to be more efficient, climate policies would have to both shift the incumbent carbon-based socio-technical systems (for it to shape decisions towards a reduction of greenhouse gas emissions) and also deconstruct habits that this same socio-technical has forged with time (as increased environmental awareness and intentions formulated accordingly are not sufficient in the presence of strong habits). Accordingly, decision-makers should design measures (e.g. commitment strategies, niche management, etc.) that, as explained in this research, specifically target those change-resisting factors and their key features. This is essential as these factors tend to reduce the efficiency of traditional instruments. Micro-level interventions are thus needed as much as macro-level ones. For instance, it is often the case that external improvements of energy efficiency do not lead to lower energy consumption due to the rebound effect arising from unchanged energy-consuming habits. Bearing this in mind and building on the insights from the evolutionary approach, policy-makers should go beyond the mere subsidisation of technologies. They should instead create conditions enabling the use of the multi-layered, cumulative and self-reinforcing character of economic change highlighted by evolutionary analyses. This means supporting both social and physical technologies with the aim of influencing the selection environment so that only the low-carbon technologies and practices will survive. Mentioned references: David, P. A. (1985), Clio and the economics of QWERTY, American Economic Review 75/2: 332–337. IPCC, 2007, ‘Climate Change 2007: The Physical Science Basis’, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 996 pp. Stern, N., 2006, ‘Stern Review: The economics of Climate Change’, Report to the UK Prime Minister and Chancellor, London, 575 p. (www.sternreview.org.uk) van den Bergh, J.C.J.M., 2007, ‘Evolutionary thinking in environmental economics’, Journal of Evolutionary Economics 17(5): 521-549.
167

Essays on the Upper Mississippi River and Illinois Waterway and U.S. grain market

Yu, Tun-Hsiang 29 August 2005 (has links)
This dissertation examines several issues regarding the congestion on the Upper Mississippi River and Illinois Waterway. Chapter II identifies and measures the impact of lock congestion on grain barge rates on these waterways. Results indicate grain barge rates on both rivers are not affected by lagged lock congestion. In present time, however, lock congestion in the lower reaches of the upper Mississippi and Illinois Rivers are found to increase barge rates that link the north central United States to the lower Mississippi Gulf port area. The findings suggest the impact of lock congestion on grain barge rates is moderate. Chapter III explores the interaction between grain prices in export and domestic markets and transportation rates linking these markets over time. Three model frameworks were evaluated and some consistent results are observed. In general, shocks in transportation rates (barge, rail, and ocean) explain a great proportion of the variation in corn and soybean market prices in the long run, suggesting the importance of transportation in grain price determination. The volatile ocean freight rates are the mostimportant transportation rates contributing to the variation in grain prices, while shocks in barge rates on the Upper Mississippi River and Illinois Waterway generally explain less than 15 percent of the variation in grain prices. The dynamic interrelationships among the six evaluated transportation rates are also found. In addition, the north central corn markets likely have the most influence over other markets while soybean export price dominates the soybean market in the long run. Chapter IV estimates the structural demand for grain barge transportation on both the upper Mississippi and Illinois Rivers. Results suggest foreign grain demand is the most influential force affecting grain barge demand on both rivers. Also, results indicate an inelastic demand for grain barge transportation on the Upper Mississippi in the short run; demand is price elastic in the long run. The price elasticity for grain barge demand on the Illinois River is consistently inelastic. Additionally, the winter season and floods affect demand on the Upper Mississippi negatively, while barge demand increases on the Illinois River in winter.
168

Ultra-Low Power Electronics for Autonomous Micro-Sensor Applications

Davidova, Rebeka 01 January 2011 (has links)
This thesis presented the research, design and fabrication associated with a unique application of rectenna technology combined with lock-in amplification. An extremely low-power harmonic transponder is conjoined with an interrogator base-station, and utilizing coherent demodulation the Remote Lock-In Amplifier (RLIA) concept is realized. Utilizing harmonic re-radiation with very low-power input, the 1st generation transponder detects a transmitted interrogation signal and responds by retransmitting the second harmonic of the signal. The 1st generation transponder performs this task while using no additional power besides that which accompanies the wireless signal. Demonstration of the first complete configuration provided proof of concept for the RLIA and feasibility of processing relevant information under "zero" power operating conditions with a remote transponder. Design and fabrication of a new transponder where the existing zero-bias transponder was modified to include a DC bias to the diode-based frequency doubler is presented. Applied bias voltage directly changed the impedance match between the receiving 1.3 GHz antenna and the diode causing a change in conversion loss. Testing demonstrated that a change in conversion loss induces an amplitude modulation on the retransmission of the signal from the transponder. A test of bias sweep at the optimal operating frequency was performed on the 2nd generation transponder and it was seen that a change of ~ 0.1 V in either a positive or negative bias configuration induced an approximate 15 dB change in transponder output power. A diode-integrated radar detector is designed to sense microwaves occurring at a certain frequency within its local environment and transform the microwave energy to a DC voltage proportional the strength of the signal impinging on its receiving antenna. The output of the radar detector could then be redirected to the bias input of the 2nd generation transponder, where this DC voltage input would cause a change in conversion loss and modulate the retransmitted interrogation signal from the transponder to the base station. When the base station receives the modulated interrogation signal the information sensed by the radar detector is extracted. Simulations and testing results of the fabricated radar detector demonstrate capability of sensing a signal of approximately -53.3 dBm, and accordingly producing a rectified DC voltage output of 0.05 mV. A comparison is made between these findings and the transponder measurements to demonstrate feasibility of pairing the radar detector and the 2nd generation transponder together at the remote sensor node to perform modulation of interrogation signals.
169

Effects of interference on carrier tracking in fading and symbol synchronization

Emad, Amin Unknown Date
No description available.
170

Working for family, nation and God, paternalism and the Dupuis Freres department store, Montreal, 1926-1952

Matthews, Mary Catherine January 1998 (has links) (PDF)
No description available.

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