This study examines several of the Confederate military operations in Texas from the years 1861 to 1865, including early defensive moves, the Battle of Galveston and the Battle of Sabine Pass.

Interferometry and coherent change detection (CCD) utilize phase differences between complex SAR images to find terrain height and to detect small changes between images, respectively. A new method for improving interferometry and CCD using multiple sub-apertures is proposed. Using backprojection processing, multiple sub-aperture images are created for a pair of flights. An interferogram and coherence map is made from each sub-aperture. For CCD, each sub-aperture coherence map offers an independent estimate of the coherence over the same area. By combining coherence maps, low coherence areas associated with residual motion errors are reduced, shadowed areas are minimized, and the overall coherence of stationary objects between images is increased. For interferometry, combining independent estimates of a scene's height offers a more accurate height estimate. For repeat-pass interferometry, multiple apertures are shown to increase the coverage of valid height estimates. The benefits of multi-aperture interferometry and CCD are shown using examples with real data.

[pt] Esta tese é composta por três artigos empíricos que utilizam dados de venda de uma cadeia de lojas de produtos eletroeletrônicos e de características de seus clientes. O primeiro investiga o efeito de características, como gênero, idade, escolaridade e renda, na probabilidade do cliente de receber desconto. Ele tem o objetivo de averiguar se a autoridade de decisão de preço final dada aos vendedores está sendo bem usada. Quando há discriminação de preços, clientes com renda mais alta devem ter menor probabilidade de receber descontos. Por outro lado, descontos podem ser dados por outros motivos, diferentes daquele desejado pela firma. Uma vez que o cliente percebe que o vendedor tem poder de decisão sobre o preço final, ele pode desejar começar um processo de barganha para reduzir o preço que pagará. O resultado deste processo pode também depender das características do cliente, se estas afetarem a habilidade de barganhar. Neste caso, quanto maior a habilidade do cliente de barganhar pelo desconto, maior este será. Como encontramos que a probabilidade de receber descontos aumenta com a renda e escolaridade do cliente, e o valor do desconto também é maior para pessoas com mais alta renda e mais educadas, concluímos que o desconto não está sendo dado como resultado de discriminação de preços, mas como o resultado de uma barganha. O segundo artigo estima o efeito de informação assimétrica sobre o financiamento da compra de produtos, usando o plano de pagamento escolhido e as características não observadas do cliente. Decompomos o efeito em seleção adversa e um componente causal, usando técnica similar à usada por Adams, Eivan and Levin (2009). Encontramos um efeito marginal significante e concluímos que o efeito causal da escolha do plano de pagamento é maior que aquele causado pela seleção adversa. Um aspecto chave da estratégia de identificação é a escolha da variável exógena. Usamos uma variável binária que é um quando a compra é feita num mês de saldão, meses estes quando há um plano especial: onze parcelas sem juros. A variável usada claramente influencia a escolha do plano de pagamento, mas o repagamento não depende diretamente dela, uma vez que nosso instrumento não está associado ao valor do colateral do empréstimo. O terceiro artigo estuda o repasse para os preços da primeira redução de IPI de 2009. A redução ocorreu para quatro diferentes produtos: refrigeradores, fogões, máquinas de lavar e tanquinhos. Observamos o efeito do IPI nos preços e nas características dos clientes. Encontramos que a ocorrência da redução do IPI gera uma redução de 5,97 porcento no preço, quando usamos um modelo linear simples e uma redução de 2,98 porcento no preço, quando usamos um efeito fixo de produto. Gênero, idade, renda e escolaridade dos clientes que compram eletrodomésticos não mudam significativamente com a redução do IPI. / [en] This dissertation is composed of three independent empirical articles that use data on home and kitchen appliances and image equipment sales of one specific chain store and their clients characteristics. The first one investigates the effect of the client s characteristics, such as gender, age, education and income, on the probability of receiving a discount. It intends to investigate if the pricing authority that is delegated to the salespeople is being well used. If the effect of delegation were to implement price discrimination, clients with higher income would have a lower probability of getting a discount. On the other hand, discounts can be given for a different reason than the one desired by the firm. Once the customer recognizes that the salesperson has some discretion over the prices, she may wish to engage in bargaining to decrease the final price. The outcome of this process may also depend on the customer s characteristics if they affect the customer s skill in bargaining. In this case, the greater the client s ability, the bigger the discount. Since we find that the probability of receiving a discount is increasing in the client s income and education, and the value of the discount is also bigger for people with higher income and better education, we conclude that the discount giving is not a result of price discrimination, but a result of a bargaining process. The second article estimates the effect of asymmetric information on consumer loans, using the payment plan chosen by the client and his observable characteristics. We decompose the effect into an adverse selection and a causal component using a technique similar to Adams, Einav and Levin (2009). We find significant marginal effects for both components and that the causal effect of the payment plan choice is greater than the one caused by the adverse selection. A key aspect of the identification strategy is the choice of the exogenous variable. We use a dummy variable that is one when the month of the purchase is one of the saldão months, that is, when one special payment plan is also available: eleven monthly payments, with zero interest rate. The variable used clearly influences the payment plan choice but the repayment behavior does not depend directly on it, since it is not directly related to the value of the debt collateral. The third article studies the retail market effects of the first tax stimulus episode of 2009, when the government reduced the IPI (Industrialized Products Tax) of certain categories of kitchen and home appliances. Tax rates vary depending on the product. The reduction occurred to four different products: refrigerators, stoves, washing machines and non automatic washing machines. We estimate the effect of the IPI reduction on prices and the composition of demand. We find that the IPI reduction lead to a 5.97 percent reduction on price, when we use a simple linear model and a 2.98 percent reduction, when we control for product fixed effects. The characteristics of consumers who acquire the appliances do not change significantly with the reduction.

京都大学 / 新制・課程博士 / 博士(エネルギー科学) / 甲第24926号 / エネ博第468号 / 新制||エネ||88(附属図書館) / 京都大学大学院エネルギー科学研究科エネルギー基礎科学専攻 / (主査)准教授 南 貴司, 教授 稲垣 滋, 教授 田中 仁 / 学位規則第4条第1項該当 / Doctor of Energy Science / Kyoto University / DFAM

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In radio frequency (RF), filtering is an essential part of RF transceivers. They are employed for different purposes of band selection, channel selection, interference cancellation, image rejection, etc. These are all translated in selecting the wanted signal while mitigating the rest. This can be performed by either selecting the desired frequency range by a band pass filter or rejecting the unwanted part by a band stop filter. Although there has been tremendous effort to design RF tunable filters, there is still lack of designs with frequency and bandwidth software-tuning capability at frequencies above 4 GHz. This prevents the implementation of Software Defined Radios (SDR) where software tuning is a critical part in supporting multiple standards and frequency bands. Designing a tunable integrated filter will not only assist in realization of SDR, but it also causes an enormous shrinkage in the size of the circuit by replacing the current bulky off-chip filters. The main purpose of this research is to design integrated band pass and band stop filters aimed to perform interference cancellation. In order to do so, two systems are proposed for this thesis. The first system is a band pass filter capable of frequency and band with tuning for C band frequency range (4-8 GHz) and is implemented in 0.13 µm BiCMOS technology. Frequency tunability is accomplished by using a variable capacitor (varactor) and bandwidth tuning is carried out by employing a negative transconductance cell to compensate for the loss of the elements. Additional circuitry is added to the band pass filter to enhance the selectivity of the filter. The second system is a band stop filter (notch) with the same capability as the band pass filter in terms of tuning. This system is implemented in C band, similar to its band stop counterpart and is capable of tuning its depth by using a negative transconductance in an LC tank. A negative feedback is added to the circuit to improve the bandwidth. While implemented in the same process as the band pass filter, it only employs CMOS transistors since it is generally more attractive due to its lower cost and scalability. Both of the systems mentioned use a varactor for changing the center frequency which is a nonlinear element. Therefore, the nonlinearity of it is modelled using two different methods of nonlinear feedback and Volterra series in order to gain further understanding of the nonlinear process taking place in the LC tank. After the validation of the models proposed using Cadence Virtuoso simulator, two methods of design and tuning are suggested to improve the linearity of the system. After post layout-extraction, the band pass filter is capable of Q tuning in the range of 3 to 270 and higher. With the noise figure of 10 to 14 dB and input 1-dB compression point as high as 2 dBm, the system shows a reasonably good performance along its operating frequency of 4 to 8 GHz. The band stop filter which is designed in the same frequency band can achieve better than 55 dB of rejection with the noise figure of 6.7 to 8.8 dB and 1-dB compression point of -4 dBm. With the power consumption of 39 to 70 mW, the band stop filter can be used in a low power receiver to suppress unwanted signals. The technique used in the band stop filter can be applied to higher frequency ranges if the circuit is implemented in a more advanced silicon technology. Implementing the mentioned filters in a receiver along with other elements of low noise amplifiers, mixers, etc. would be a major step toward full implementation of SDR systems. Studying the linearity theory of varactors would help future designers identify the sources of nonlinearity and suggest more efficient tuning techniques to improve the linearity of RF electronic systems. / Master of Science

In recent years, the wireless industry has witnessed tremendous development for the defense and commercial segments. The explosive growth in the modern radio frequency and microwave systems leads to an increased interest in the research of miniaturized microwave circuits with superior performance. Broadband components, in particular band pass filters (BPFs) and couplers are some of the widely used components in the modern communication systems, software defined radios, cognitive radios, imaging systems and positioning radars. In order to meet these requirements, the use of innovative geometries, a thorough understanding of their behavior by appropriate analytical techniques and the use of appropriate fabrication approaches are essential. This thesis is an effort in this direction. In this thesis work, an aperture in the ground plane is used to achieve the tight coupling in the edge and broadside-coupled coupled lines which may be otherwise difficult due to the fabrication limitations. Since microstrip lines with an aperture in the ground plane are found to be very useful in various MIC and MMIC components, closed form analytical expressions developed here will be useful for their initial synthesis. The performances of components using these are enhanced using open/short circuited resonators, spurlines and stubs. A quasi-static approach has been investigated to obtain simple closed form expressions for a microstrip line with a rectangular aperture in the ground plane. The effect of a rectangular aperture in the ground plane has been incorporated in the commonly used expressions of a regular microstrip line by introducing the concept of an equivalent effective height. The expressions for the effective height microstrip geometries with defected ground are obtained and this has been further extended to various possibilities of two-conductor and three-conductor coupled lines. Analysis of the filters and the couplers are mainly based on the even and odd mode propagation characteristics of coupled lines. This approach is extended in this thesis for three conductor coupled lines. Novel broadband BPFs and couplers and dual band pass filters employing various coupled line configurations and defected ground have been developed in this research work. Most of these components have been implemented on a regular microwave laminate or LTCC medium (planar or multi-layer) and tested for the required RF performances. The experimental results were compared against the analytically computed results based on the circuit models and the full wave simulations using electromagnetic (EM) simulations for the validation. The results are in good agreement. With practical requirements of the organization in mind, additional design elements such as open circuit stubs have been incorporated in some of these designs to achieve the desired performance. It is expected that the wideband filter (3.0GHz to 3.8GHz) and the broadband coupler (4GHz to 6GHz) developed in this thesis work would be deployed in systems developed at the Central Research Laboratory, Bharat Electronics Limited, Bangalore, India. In summary, the present doctoral work strives to (i) establish a simplified analysis method for the microstrip lines and coupled microstrip lines with a rectangular aperture in the ground plane, (ii) extend the even and odd mode analysis of the coupled lines for several new coupled line configurations, (iii) design novel broadband microwave filters, dual band filter and couplers using both these, (iv) fabricate these devices using the planar technologies including LTCC, and (v) validate the analysis and design with important practical applications.

Disertační práce se zabývá syntézou a analýzou nových obvodových struktur neceločíselného (fraktálního) řádu s řiditelnými parametry. Hlavní cíl této práce je návrh nových řešení filtračních struktur fraktálního řádu v proudovém módu, emulátorů prvků fraktálního řádu a také oscilátorů. Práce obsahuje návrh tří emulátorů pasivního prvku fraktálního řádu, tři filtrační struktury a dva oscilátory navržené na základě využití pasivního prvku fraktálního řádu v jejich obvodové struktuře a dvě obecné koncepce filtrů fraktálního řádu založené na využití aproximace přenosové funkce fraktálního řádu. Na základě obecných koncepcí jsou v práci navrženy filtry fraktálního řádu typu dolní a horní propust. Díky aktivním prvkům s přeladitelnými parametry, které jsou užity v obvodových strukturách je zajištěna řiditelnost řádu filtru, jeho pólového kmitočtu a některých případech i činitele jakosti. Vlastnosti všech zapojení jsou ověřeny počítačovými simulacemi za pomoci behavioralních simulačních modelů aktivních prvků. Některé z uvedených obvodů byly realizovány na DPS a jejich vlastnosti ověřeny experimentálním měřením.

This thesis deals with concept of universal frequency filter by application of a switched-capacitor functional block. The concept is based on the theory of switched-capacitor circuits and the theory of a design of classical frequency filters. The printed circuit board was designed based on the filter connection developed by using a software Eagle. The filter was implemented as a laboratory product. This product has been revitalized and the frequency response of all types of filters has been measured. The measured parameters were compared with the parameters set out in the technical documentation of functional block.