Made available in DSpace on 2015-07-22T20:50:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-25. Added 1 bitstream(s) on 2015-08-11T03:25:27Z : No. of bitstreams: 1 Publico-00241.pdf: 1343802 bytes, checksum: c09cdd2f6fac68d70a68a3328dedd440 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Apesar do subtipo B ser o mais predominante na epidemia de aids no Brasil, existem evidências que esse subtipo não é homogêneo. O subtipo B apresenta no Brasil uma assinatura no tetrâmero da coroa V3 da gp120 que é a presença de um triptofano (W) ao invés de prolina (P) que é o aminoácido mais freqüente nessa posição do genoma do HIV-1. Aproximadamente metade dos isolados do subtipo B no Brasil possuem um triptofano (W) no tetrâmero do loop V3 da gp120 (GWGR). Essa freqüência não é observada em outros subtipos e nem mesmo no subtipo B em outras epidemias de aids no mundo. Para explorar mais as características das variantes GWGR e GPGR foi realizada uma análise detalhada incluindo inferências filogenéticas, análise de diversidade genética e de pressão seletiva em seqüências dos genes env, pol e gag. Os resultados da análise de diversidade genética e pressão seletiva mostraram que os valores da razão entre dN/dS entre os genes são distintos. Para uma aferição mais precisa da pressão seletiva sugerida pelo método par-a-par foram realizadas análises usando um método de verossimilhança que estima os valores de dN/dS em cada códon individualmente presente no alinhamento de seqüências. Os resultados obtidos com essa análise indicaram códons sob seleção positiva ao longo da seqüência da região dos genes env, pol e gag do HIV-1 em ambas as variantes. Para realmente definir se amostras GWGR e GPGR são variantes distintas ou amostras que contêm apenas uma assinatura diferenciada em env, foi composta uma seqüência concatâmera e comparada a distribuição de ambas as amostras em um agrupamento filogenético. Essa análise mostrou que as amostras GWGR não são variantes distintas do subtipo B brasileiro, mas apenas seqüências com assinaturas diferentes. A distribuição encontrada demonstrou que não houve separação das amostras GWGR e GPGR e sim uma total mistura entre elas. Essas análises mostraram que os vírus que contém W ou P no loop V3 não estão evoluindo diferencialmente na epidemia de aids no Brasil e não são variantes distintas. Possivelmente, os vírus que contêm a variante GWGR entraram cedo na epidemia (efeito fundador), sofrendo disseminação no Brasil. / FAPESP: 06/53818-6 / FAPESP: 06/53818-7 / TEDE / BV UNIFESP: Teses e dissertações

The cutter is a fundamental machine tool used extensively throughout manufacturing industries. The performance and quality of the cutter have a direct influence upon the cutting precision, product quality and production rate. Invigorating the domestic cutter industry and establishing a characteristic syscxtem of cutter technology requires that new technology be imported, the constraints of previous experience be overcome, a fundamental research and development capability be developed and new machine tool materials be adopted Two basic approaches exist when considering geometrical models of the cutter. In the first approach, developing new cutters and establishing an optimal set of cutter design parameters is performed in accordance with general cutting theory and the operational functions of the machine tool. Meanwhile, in the second approach, the structural requirements and design parameters of an ideal cutter are used to establish a geometrical cutter model which describes the various contours of the cutter. Developing an accurate geometrical model is an essential prerequisite to realizing the com-puter-aided design of a cutter, and is necessary in order to apply the theory of cutter design and manufacturing theory to the practical manufacturing proc-ess. Moreover, the geometrical model provides the basis for interference checking and manufacturing error analysis. Modern cutter design and manufacturing technologies integrate the results from a diverse range of previous studies, including those performed within the fields of fundamental mathematical theory, computer-aided ap-plication technology, modern design technology, material science and manufacturing technology. In each field, technological progress is reliant upon the development of mathematical theory. In the present study, differen-tial geometry, conjugate theory, engagement relationship theory, coordinate transfer and numerical methods are used to develop a systematic method for the design, simulation, manufacturing and compensation of special revolving cutters. Using the proposed mathematical models, this paper presents real-izable and effective manufacturing models for these revolving cutters. Fur-thermore, the Taguchi method and power signal analysis techniques are em-ployed to investigate the effects of different cutting-edge curves on the cut-ting characteristics of Inconel tool material. The basic research activities performed within the present study can be summarized as follows: 1.The study develops geometrical models for the cutting-edge curves and flute designs of ball-end cutters, truncated-cone ball-end cutters and toroid-cone shape cutters. Applying the inverse-envelope theory, a geometrical model for the cross-section of the grinding wheel used to grind the required helical groove on the cutter is developed. Further-more, the relative positions and velocities of the grinding wheel and workpiece during the NC manufacturing of the cutter are developed and investigated via a process of computer simulation. Finally, a compensation method is developed which resolves the problems of residual revolution surface and localized non-existence of the cutting-edge. The theoretical models and results provide a valuable source of reference for the NC manufacturing of revolving cutters. 2.A series of experiments are performed to investigate the effects of the cutting-edge geometry on the machining performance when machining Inconel 718. The Taguchi method is adopted to determine the set of optimal machining parameters for a variety of cutting-edge types, in-cluding those of the truncated-cone ball-end cutter, the plane type, the S type and the traditional type. The results of these experiments serve as a valuable reference for the automated machining of aero-materials. 3.Study the design and manufacture of the cutting-edge curve, flute sur-face and the coning angle of the grinding wheel for both the rotating burr and the revolving cutter, and discuss the difference of the related geometrical models. Also, the practical cutting-edge curve and the feeding rate of the relative movement for the cutter of the two and half axes processes of the NC machine have been discussed.

This dissertation examines the prediction of speech intelligibility and quality using simulated auditory nerve fiber activity. The relationship of neural mean-rate and spike-timing activity to the perceptual salience of the envelope (ENV) and temporal fine-structure (TFS) of speech is indistinct. TFS affects neural temporal coding in two ways. TFS produces phase-locked spike-timing responses and narrowband cochlear filtering of TFS generates recovered ENV. These processes, with direct encoding of ENV to mean-rate responses, are the established transduction processes. We postulate that models based on mean-rate (over a time-window of approx. 6 to 16 ms) and spike-timing cues should produce accurate predictions of subjectively graded speech. Two studies are presented. The first study examined the contribution of mean-rate and spike-timing cues to predicting intelligibility. The relative level of mean-rate and spike-timing cues were manipulated using chimaerically vocoded speech. The Spectro-Temporal Modulation Index (STMI) and Neurogram SIMilarity (NSIM) were used to quantify the mean-rate and spike-timing activity. Linear regression models were developed using the STMI and NSIM. An interpretable model combining the STMI and the fine-timing NSIM demonstrated the most accurate predictions of the graded speech. The second study examined the contribution of mean-rate and spike-timing cues for predicting the quality of enhanced wideband speech. The mean-rate and fine-timing NSIM were used to quantify the mean-rate and spike-timing activity. Linear regression models were developed using the NSIM measures and optimization of the NSIM was investigated. A quality-optimized model with intermediate temporal resolution had the best predictive performance. The modelling approach used here allows for the study of normal and impaired hearing. It supports the design of hearing-aid processing algorithms and furthers the understanding how TFS cues might be applied in cochlear implant stimulation schemes. / Thesis / Doctor of Philosophy (PhD) / This dissertation examines how auditory nerve fiber activity can be used to predict speech intelligibility and quality. A model of the cochlea is used to generate simulated auditory nerve fiber responses to speech stimuli and the information conveyed by the corresponding spike-events is quantified using different measures of neural activity. A set of predictive models are constructed in a systematic manner using these neural measures and used to estimate the perceptual scoring of intelligibility and quality of normal-hearing listeners for two speech datasets. The results indicate that a model combining a measure of average neural discharge activity with a measure of instantaneous activity provides the best prediction accuracy. This work contributes to the knowledge of neural coding in the cochlea and higher centers of the brain and facilitates the development of hearing-aid and cochlear implant processing strategies.

No description available.

Bandwidth estimation has been extensively researched in the past. The majority of existing methods assume either negligible or fluid cross-traffic in the network during the analysis. However, on the present-day Internet, these assumptions do not always hold right. Hence, over such paths the existing bandwidth estimation techniques become inaccurate. In this thesis, we explore the problem assuming arbitrary cross-traffic and develop a new probing method called Envelope, which can simultaneously estimate bottleneck and available bandwidth over an end-to-end path with multiple heavily congested links. Envelope is based on a recursive extension of the stochastic queuing model first proposed by Kang, Liu, Dai and Loguinov (2004), and a modified packet-train methodology. We use two small packets to surround the probing packet-trains and preserve the inter-packet spacing of probe traffic at each router in the path-suffix. The preserved spacings are then used by the receiver to estimate bandwidth. We first reproduce results for a single congested router case using the model proposed by Kang et al. Next, we extend it to the case of multiple congested routers with arbitrary cross-traffic and develop the methodology Envelope. We evaluate the performance of Envelope in various network path topologies and cross-traffic conditions through extensive NS-2 simulations. We also evaluate various probe-traffic parameters which affect the accuracy of this method and obtain the range of values for these parameters that provide good estimation results. Finally, we compare the bandwidth estimation results of our method with the results of other existing methods such as IGI (2003) , Spruce (2003), Pathload (2002), and CapProbe (June 2004) using simulation in Network Simulator (NS-2) with varied network topologies and cross-traffic.

Bandwidth estimation has been extensively researched in the past. The majority of existing methods assume either negligible or fluid cross-traffic in the network during the analysis. However, on the present-day Internet, these assumptions do not always hold right. Hence, over such paths the existing bandwidth estimation techniques become inaccurate. In this thesis, we explore the problem assuming arbitrary cross-traffic and develop a new probing method called Envelope, which can simultaneously estimate bottleneck and available bandwidth over an end-to-end path with multiple heavily congested links. Envelope is based on a recursive extension of the stochastic queuing model first proposed by Kang, Liu, Dai and Loguinov (2004), and a modified packet-train methodology. We use two small packets to surround the probing packet-trains and preserve the inter-packet spacing of probe traffic at each router in the path-suffix. The preserved spacings are then used by the receiver to estimate bandwidth. We first reproduce results for a single congested router case using the model proposed by Kang et al. Next, we extend it to the case of multiple congested routers with arbitrary cross-traffic and develop the methodology Envelope. We evaluate the performance of Envelope in various network path topologies and cross-traffic conditions through extensive NS-2 simulations. We also evaluate various probe-traffic parameters which affect the accuracy of this method and obtain the range of values for these parameters that provide good estimation results. Finally, we compare the bandwidth estimation results of our method with the results of other existing methods such as IGI (2003) , Spruce (2003), Pathload (2002), and CapProbe (June 2004) using simulation in Network Simulator (NS-2) with varied network topologies and cross-traffic.

The thesis investigates how ambiguity - created through a smooth, continuous building envelope- can be used to alter the perception and understanding of discrete typological or primitive forms with a focus on material expression. The use of basic, primitive forms is tied to a contemporary discourse of discreteness. Contemporary practitioners are exhausted with the seductive, smooth, continuous envelopes from the 90s digital project. As a result, they have turned to generating form through loosely associated, blocky parts. However, the thesis proves - through a vast series of investigations - that there is still room to explore smooth envelopes and gradients from the 90s project - as it relates to the creation of ambiguity - with the discrete, primitive forms of contemporary discourse in order to propose an alternative way of generating form through loosely associated, blocky parts. Furthermore, by deploying basic, primitive forms, the task of analysis and interpretation is open to a larger audience. The ambiguous techniques that the thesis explores serve to challenge the typical viewer's perception of the familiar, primitive forms. By challenging their perceptions, the thesis asks for their participation and reinterpretation of the basic volumes. As a result of this participation from multiple audiences, the discipline of architecture becomes open to more people and ideas. / Master of Architecture / The thesis investigates how a continuous and ambiguous building envelope can be used to alter the perception and understanding of individual, familiar forms with a focus on material expression. Contemporary practitioners are focusing on how to generate form through individual, basic geometric objects - cubes, cylinders, cones, etc. However, the thesis proves - through a vast series of investigations - that there is room to explore continuous, smooth building envelopes with the contemporary discrete, basic objects in order to propose an alternative way of generating form through individual, basic parts. Furthermore, by deploying basic objects, the task of analysis and interpretation is open to a larger audience. The ambiguous techniques that the thesis explores serve to challenge the typical viewer's perception of the familiar objects. By challenging their perceptions, the thesis asks for their participation and reinterpretation of the volumes. As a result of this participation from multiple audiences, the discipline of architecture becomes open to more people and ideas.

The world is filled with richly diverse sounds which we are able to perceptually distinguish using a variety of properties. One of these properties is the amplitude envelope, or the intensity of a sound over time. While it is common in the real world for sounds to have time-varying amplitude envelopes, the majority of sounds used in perceptual research have time-invariant or unspecified amplitude envelopes. The aim of the present thesis is twofold. Because many of the studies using time-invariant or undefined envelopes make use of very short sounds (below 100 msec), the first experiment aimed to determine the duration required for discriminating among three different envelopes: flat (invariant), ramped (increasing in intensity over time), and damped (decreasing in intensity over time). In Experiment 1, participants took part in a 2-alternative forced choice, psychophysical staircase paradigm in which they indicated which of two envelopes they thought they were listening to. Results showed that, when telling ramped tones apart from either flat or damped tones, participants showed discrimination thresholds below 50 msec, while they had thresholds of approximately 75-80 msec when differentiating flat from damped tones. Because amplitude envelope has been shown to impact audiovisual integration and the perceptual system is sensitive to interaural envelope differences when localizing sounds, the second experiment aimed to determine whether amplitude envelope could modulate the visual bias present in spatial ventriloquism, an audiovisual illusion where the perceived location of a sound is influenced by the location of a visual stimulus. In Experiment 2, participants performed a psychophysical staircase task which measured their accuracy in localizing sounds with flat and damped envelopes, with or without a simultaneous flash on the screen in front of them. Results showed that, at durations above the envelope discrimination thresholds found in Experiment 1 (83 msec), there was no visual bias on perceived location of the sound, while the bias was present at a duration below this threshold (16 msec). Together, these results add to the mounting evidence suggesting that amplitude envelope has profound and varied effects on our perception of sounds, and is an important property to consider when designing experiments. / Thesis / Master of Science (MSc)

No description available.

This effort is comprised of three interwoven tasks: Decipher an evolving urban place, across a range of scales, to establish an informed point of departure for proposing a change. Attend to the particular imperative purpose of accommodating those among us who are most at risk, and who make their way through life without adequate resources. Design an individual cumulative form wherein the new architecture incorporates a rejuvenated existing structure, and the entire ensemble contributes something worthwhile to the neighborhood. / Master of Architecture / This is an attempt to understand one street corner, think about how architecture can assist people who really need help, and design a building which asserts its identity even as it fits into its surroundings. It's one approach to making individual, incremental changes that can accumulate to our collective benefit as we carry on with the transformation of our city.