Essay 1: People’s planning to evade the inheritance tax curtails its merits. However, the extent of planning remains a matter of argument. According to popular belief, it is widespread, but few estimates have been presented. This study estimates the extent of estate size under-reporting, a form of inheritance tax planning, using the repeal of the Swedish tax on spousal bequests, in 2004, and a regression discontinuity design. The results show that, on average, estate sizes were 17 percent lower, and the share of estates that completely escaped tax payments was 26 percent larger due to under-reporting. As a consequence, government revenues from the tax were only half of what they would have been without under-reporting. Moreover, preferences and means for under-reporting were not only prevalent among the wealthy, but also among those receiving relatively small inheritances. The study contributes to a growing literature on tax avoidance and evasion by estimating the extent of estate size under-reporting, its effect on government revenues and by showing that it was widespread in the population. / Essay 2: There is an ongoing debate about whether or not inheritance and estate taxes are effective in raising revenues and in contributing to a more equal society. The different views on transfer taxes are largely dependent on beliefs about whether people plan their wealth to avoid these taxes. In this paper, we follow Kopczuk (2007) and study people's planning response to the onset of terminal illness. An extension of Kopczuk’s work is that we can effectively control for responses in wealth caused by terminal illness but unrelated to tax planning. We do this by exploiting a tax reform in Sweden that removed the incentives for people to plan their estates to avoid inheritance taxation. We find some evidence of long-term terminal illness inducing responses consistent with tax planning, but that these are not widespread or efficient enough to reduce the overall tax burden in the study population. Our results, similarly to those of Kopczuk, show that people appear to postpone some decisions about their estates until shortly before death. / Essay 3: Small businesses form an essential part of all economies, making it necessary to understand the conditions under which they operate. This paper contributes to that understanding by studying how survival, income and profits of small businesses change when their owners receive inheritances. Using a difference-in-differences strategy and Swedish registry data on small businesses and estate reports, it is shown that survival rates increase with almost three percentage points when the owners receive inheritances of, on average, SEK 275,000. However, the profits of the surviving small businesses and the income of their owners do not increase, indicating that the inheritance did not increase survival by making investments possible, investments to increase profits and income, but by enabling small business owners of lower ability to subsist. The study contributes to the literature on the conditions for small businesses by providing causal evidence on the effect of increased access to capital among existing businesses. It thereby complements the rich literature on the role of capital for small business start-ups. / Essay 4: This article shows that a simple monetary incentive can dramatically reduce electric energy consumption (EEC) in the residential sector and simultaneously achieve a more desirable allocation of EEC costs. The analyses are based on data from a policy experiment conducted in 2011 and 2012 by a private housing company in about 1,800 apartments. Roughly 800 of the tenants (treatment group) were subject to a change from having unlimited EEC included in their rent to having to pay the market price for their own EEC. This change was achieved by installing EEC meters in each apartment. Tenants in the other 1,000 apartments (control group) experienced no policy change and were subject to apartment-level billing and metering during the entire study period. Using a quasiexperimental research design and daily data on EEC from 2007 to 2015, we estimate that apartment-level billing and metering permanently reduce EEC by about 25%. Moreover, we show that households reduce EEC immediately after being informed that they will be billed for EEC, the reduction is larger when the production cost is higher, and the reduction in EEC comes almost exclusively from households with very high EEC before the policy change. Finally, we show that apartment-level billing and metering are cost-effective, with a cost per reduced kilowatt hour of US$0.01, and for each invested dollar, the social value of reductions in air pollution, including CO2 emissions, is $2.

M. Tech. (Chemical Engineering) / The usual target of an upgrading process using membrane is to produce a retentate stream, the product, with high CH4 concentration. This work presents a simulation of two possible membrane configurations, single stage without recycle (SSWR) and double stage with permeate recycle (DSPR), of an existing operational biogas upgrading plant. The simulation was conducted using ChemCAD and AlmeeSoft gas permeation software to investigate the performance of the configurations on product purity, recovery and required compressor power with a view to determine the optimal operational conditions for maximising the concentration of CH4 and its recovery. Thereafter, an economic assessment on the optimal configuration was conducted to determine the gas processing cost (GPC), the profitability of producing biomethane and cost-benefit of utilising biomethane as a vehicular fuel. The simulation was validated against plant data with a maximum percentage error of 2.64%. Increasing CO2 in feed reduced product recovery and purity. Increasing feed pressure and selectivity increased product recovery and purity up to the pressure limit of the membrane module. Increasing feed flow rate increased product recovery but reduces purity. In both configurations, increasing CO2 in the feed and increasing feed pressure increased the GPC. However, increasing feed flow rate reduced the GPC. The overall performance of DSPR configuration was much higher due to increased trans-membrane area available for separation. At optimal conditions, a product purity of 91% and 96% CH4 recovery was achieved from the initial plant result of 87.2% product purity and 91.16% CH4 recovery. The total compression duty was 141 kW. The GPC was $0.46/m3 of biomethane. The cumulative discounted NPV, IRR and BCR for producing biomethane was R15,240,343, 22.41% and 2.05 respectively, with a break-even in the 5th year after plant start-up considering a prime lending rate at 9%. Using CBG instead of gasoline saves 34% of annual fuel cost with a payback period of one year and three months for the cost of retrofitting the vehicle.

Ce travail de thèse est consacré à la modélisation et simulation numérique d'écoulements diphasiques liquide-gaz mettant en jeu des transferts de chaleur. La simulation de configurations où la prise en compte des effets de compressibilité de la phase gazeuse est indispensable (micropompes, microactionneurs, etc...) a nécessité l'utilisation d'un modèle original, considérant le liquide incompressible et le gaz compressible sous l'hypothèse faible Mach. Lors de cette thèse, ce modèle a été implémenté dans un code diphasique prenant en compte l'interface à l'aide d'une méthode de front-tracking. Des cas tests ont été développés spécifiquement afin de vérifier la conservation de l'énergie pour des configurations de complexité croissante. Les résultats des cas tests ont permis de mettre en évidence la difficulté à assurer la conservation de l'énergie lorsque l'interface n'est pas discontinue mais lissée, comme c'est le cas dans la méthode de front-tracking standard. Une méthode de traitement d'interface hybride a été proposée, rétablissant le caractère discontinu de l'interface avec la reconstruction d'une fonction indicatrice de phase échelon, tandis que le déplacement de l'interface est assuré d'un pas de temps à l'autre à l'aide du front-tracking. Les résultats obtenus avec cette nouvelle méthode hybride sont très satisfaisants, la méthode hybride permettant d'assurer la conservation de l'énergie et de la masse avec précision dans les simulations. / This thesis is devoted to the modeling and the numerical simulation of liquid-gas flows in non isothermal micro-cavities or micro-channels. The objective is to describe two-phase flows in which compressibility of the gaseous phase plays a key role (as for instance in micropumps, microactuators, etc...). An original model is developed, considering in the same computational domain, an incompressible liquid and a compressible gas under the low Mach approximation. This model has been implemented in a code using the front-tracking method for the interface description. In order to check the proper satisfaction of the energy balance, specific test cases have been developed considering several configurations of increasing complexity. It has been shown from these test cases that energy conservation can hardly be satisfied when the interface is described by the means of a smooth function, which is done in the front-tracking method. An hybrid method has been proposed, restoring the discontinous nature of the interface. It makes use of a step function combined with the front tracking method. Results obtained with this new hybrid method show that mass conservation and energy balance are very properly enforced during the computations. This thesis is devoted to the modelling and numerical simulation of liqui-gas flow envolving heat transfer. Simulation of configurations where it is essential to take into account the compressibility nature of the gaseous phase(for instance micropumps, microactuators, etc...) require the use of an original model, considering an incompressible liquid and a compressible gas under the low Mach assuption. During this thesis, the model has been implemented in a multiphase flow code using the front-tracking method to handle the interface. Test cases have been developped specifically to check the energy conservation for differents configurations of an increasing complexity. Numerical results highlighted difficulties encountered to ensure the energy conservation while using smooth description of the interface, as it is the case in the standard front-tracking method. An hybrid method has been proposed, restoring the discontinous character of the interface by reconstructing a step maker function, whereas the front displacement from a time step to the next, is still handled with the front-tracking. Results obtained using this new hybride method are very satisfactory, the hybrid method allowing the code to ensure accurately the energy and mass conservation during the computations.

Este trabalho apresenta uma metodologia para a determinação do potencial de conservação de energia elétrica de usos finais, orientada para a análise de instalações de ensino, aplicável, também, a instalações comerciais em geral. Os usos finais considerados no trabalho são: iluminação, ar condicionado, microcomputadores pessoais e outros equipamentos elétricos. São apresentados procedimentos para o levantamento de dados e para a determinação do potencial de conservação de energia elétrica de cada uso final analisado, além de uma metodologia estatística para a análise de contas de energia elétrica. São definidos, também, indicadores do uso de energia elétrica bastante úteis em diagnósticos energéticos, permitindo estimar o potencial de conservação da instalação a partir da análise comparativa de seus índices com valores típicos obtidos em outros diagnósticos energéticos ou em publicações especializadas. A aplicação prática da metodologia é apresentada na forma de um estudo de caso, realizado em 1996 na Cidade Universitária Armando de Salles Oliveira - CUASO, o maior campus da Universidade de São Paulo – USP e um dos maiores do Brasil, localizado na cidade de São Paulo. Um volume considerável de informações é analisado e discutido em detalhes, fornecendo dados globais e desagregados em usos finais sobre as características de consumo e os potenciais de conservação de energia elétrica do campus. / This work presents a methodology for determining the potential of electric energy conservation of electricity end uses. The methodology is oriented to university premises, but it is also applicable to other types of installations. End uses considered in this work include lighting, air conditioning, personal computers and other electric devices. Procedures for data gathering and determination of conservation potential of each end use are presented. A statistical methodology for analyzing electricity bills is also presented. Furthermore, some useful indicators for energy diagnoses are developed. These indicators allow the estimation of the conservation potential of a given installation through comparison with typical values extracted from the other energy diagnoses or technical literature. The proposed methodology was applied in the main campus of University of São Paulo – USP, one of the largest in Brazil with some 30,000 undergraduate students. A large amount of data is analyzed and discussed, yielding global and specific indicators regarding end use characteristics and conservation potential within the campus.

Thesis. 1977. M.C.P.--Massachusetts Institute of Technology. Dept. of Urban Studies and Planning. / MICROFICHE COPY AVAILABLE IN ARCHIES AND ROTCH. / Includes bibliographical references. / M.C.P.

The low complexity of IIR adaptive filters (AFs) is specially appealing to realtime applications but some drawbacks have been preventing their widespread use so far. For gradient based IIR AFs, adverse operational conditions cause convergence problems in system identification scenarios: underdamped and clustered poles, undermodelling or non-white input signals lead to error surfaces where the adaptation nearly stops on large plateaus or get stuck at sub-optimal local minima that can not be identified as such a priori. Furthermore, the non-stationarity in the input regressor brought by the filter recursivity and the approximations made by the update rules of the stochastic gradient algorithms constrain the learning step size to small values, causing slow convergence. In this work, we propose IIR performance enhancement strategies based on hybrid combinations of AFs that achieve higher convergence rates than ordinary IIR AFs while keeping the stability. / A baixa complexidade dos filtros adaptativos (FAs) IIR é atrativa para aplicações em tempo real, mas certos inconvenientes têm impedido sua ampla utilização até agora. Para os FAs baseados no gradiente descendente, condições operacionais adversas suscitam problemas de convergência em cenários de identificação de sistemas: pólos subamortecidos ou agrupados, submodelagem ou sinais correlacionados originam superfícies de erro onde a adaptação desacelera em grandes planícies ou para em mínimos locais sub-ótimos que não podem ser identificados como tais a priori. Além disso, a não-estacionaridade do regressor de entrada causada pela recursividade do filtro e as aproximações feitas pelas regras de atualização dos algoritmos de gradiente estocástico restringem o passo de aprendizado a valores pequenos, retardando a convergência. Neste trabalho, propomos estratégias de aprimoramento de desempenho baseadas em combinações híbridas e estáveis de FAs que alcançam taxas de convergências mais altas do que FAs IIR comuns.

The low complexity of IIR adaptive filters (AFs) is specially appealing to realtime applications but some drawbacks have been preventing their widespread use so far. For gradient based IIR AFs, adverse operational conditions cause convergence problems in system identification scenarios: underdamped and clustered poles, undermodelling or non-white input signals lead to error surfaces where the adaptation nearly stops on large plateaus or get stuck at sub-optimal local minima that can not be identified as such a priori. Furthermore, the non-stationarity in the input regressor brought by the filter recursivity and the approximations made by the update rules of the stochastic gradient algorithms constrain the learning step size to small values, causing slow convergence. In this work, we propose IIR performance enhancement strategies based on hybrid combinations of AFs that achieve higher convergence rates than ordinary IIR AFs while keeping the stability. / A baixa complexidade dos filtros adaptativos (FAs) IIR é atrativa para aplicações em tempo real, mas certos inconvenientes têm impedido sua ampla utilização até agora. Para os FAs baseados no gradiente descendente, condições operacionais adversas suscitam problemas de convergência em cenários de identificação de sistemas: pólos subamortecidos ou agrupados, submodelagem ou sinais correlacionados originam superfícies de erro onde a adaptação desacelera em grandes planícies ou para em mínimos locais sub-ótimos que não podem ser identificados como tais a priori. Além disso, a não-estacionaridade do regressor de entrada causada pela recursividade do filtro e as aproximações feitas pelas regras de atualização dos algoritmos de gradiente estocástico restringem o passo de aprendizado a valores pequenos, retardando a convergência. Neste trabalho, propomos estratégias de aprimoramento de desempenho baseadas em combinações híbridas e estáveis de FAs que alcançam taxas de convergências mais altas do que FAs IIR comuns.

Este trabalho apresenta uma metodologia para a determinação do potencial de conservação de energia elétrica de usos finais, orientada para a análise de instalações de ensino, aplicável, também, a instalações comerciais em geral. Os usos finais considerados no trabalho são: iluminação, ar condicionado, microcomputadores pessoais e outros equipamentos elétricos. São apresentados procedimentos para o levantamento de dados e para a determinação do potencial de conservação de energia elétrica de cada uso final analisado, além de uma metodologia estatística para a análise de contas de energia elétrica. São definidos, também, indicadores do uso de energia elétrica bastante úteis em diagnósticos energéticos, permitindo estimar o potencial de conservação da instalação a partir da análise comparativa de seus índices com valores típicos obtidos em outros diagnósticos energéticos ou em publicações especializadas. A aplicação prática da metodologia é apresentada na forma de um estudo de caso, realizado em 1996 na Cidade Universitária Armando de Salles Oliveira - CUASO, o maior campus da Universidade de São Paulo – USP e um dos maiores do Brasil, localizado na cidade de São Paulo. Um volume considerável de informações é analisado e discutido em detalhes, fornecendo dados globais e desagregados em usos finais sobre as características de consumo e os potenciais de conservação de energia elétrica do campus. / This work presents a methodology for determining the potential of electric energy conservation of electricity end uses. The methodology is oriented to university premises, but it is also applicable to other types of installations. End uses considered in this work include lighting, air conditioning, personal computers and other electric devices. Procedures for data gathering and determination of conservation potential of each end use are presented. A statistical methodology for analyzing electricity bills is also presented. Furthermore, some useful indicators for energy diagnoses are developed. These indicators allow the estimation of the conservation potential of a given installation through comparison with typical values extracted from the other energy diagnoses or technical literature. The proposed methodology was applied in the main campus of University of São Paulo – USP, one of the largest in Brazil with some 30,000 undergraduate students. A large amount of data is analyzed and discussed, yielding global and specific indicators regarding end use characteristics and conservation potential within the campus.

La représentation de la consommation d’électricité et des comportements associés est abordée sous l’angle des anticipations que l’individu met en œuvre. Selon la théorie des niveaux de construit (Trope & Liberman, 2003) nous avons demandé à des individus d’apprécier leur consommation d’électricité en termes de gestes (bas niveau de construit) et de consommation (haut-niveau de construit) à différentes échelles temporelles (d’aujourd’hui à 15 ans). Dans un premier programme de recherche, les estimations étaient exprimées en termes comparatifs (se comparer à quelqu’un de votre âge). Une distance temporelle longue entraîne des estimations plus désirables dans le sens où les individus (population étudiante et générale) déclarent davantage d’actions chez eux que leurs pairs. Les participants déclarent effectuer plus de gestes et consommer moins d’électricité à long terme plutôt qu'à court terme. Cet effet est annulé par des habitudes pro-environnementales fortes et disparait au-delà de 50 ans. Des feedbacks normatifs permettent de corriger ces estimations. Un second programme de recherche portait sur l’influence de feedbacks normatifs sur la mise en veille de son ordinateur dans un contexte professionnel. Ce type de feedback permet d’obtenir une augmentation importante de mise en veille (jusqu’à un mois après) chez les individus effectuant peu par le passé ce comportement. La promotion de la réduction de la consommation d’électricité peut être renforcée par les niveaux de construit et les feedbacks normatifs. / The representation of electric energy consumption and the-related behaviours is addressed from the perspective of the individual's forecasting. According to the construal level theory (Trope & Liberman, 2003) we asked individuals to assess their electric energy consumption in terms of actions (low level of construal) and consumption (high level of construal) at different time perspectives (from today to 15 years from now). In a first research program, the assessments were expressed comparatively (same as people of my age). A long temporal distance leads to more desirable assessments in that the individuals (students and general population) reported more actions relatively to their peers. Participants stated that they would perform more actions and consume less electric energy consumption in long term rather than short term. This effect is cancelled through strong pro-environmental habits and disappears beyond 50 years old. Normative feedbacks allow for correcting these assessments. A second research program dealt with the influence of normative feedbacks on the use of the computer sleep mode within a professional context. This type of feedback provides significant increase in setting up sleep mode (up to one month after) for individuals that previously didn't do it much. The promotion of energy conservation can be enhanced by construal levels and normative feedbacks.

This work presents a new energy saving technique for modern digital designs. We propose Time Interleaved Multi-Rail (TIMR) - a method for providing two dynamic supply rails to a circuit. This technique uses the first supply rail to mask the transition delay while changing the voltage of the second rail. We examine the design of TIMR as well as the implementation and considerations. We propose a number of control schemes that range from traditional DVFS to "race to sleep". This thesis also shows simulations of the technique using a existing voltage regulator in order to find the time and energy overhead of implementing the design. We find a 100μs switching time delay and 118μJ energy overhead associated with changing the voltage rail. This work concludes with comparisons to current energy saving techniques. / Graduation date: 2012