No description available.

No description available.

<p> The work in this thesis is to develop a tool for calculating the parameters corresponding to certain theoretical model of dielectric relaxation phenomena and then doing the curve fitting using the result after fetching the data from the user. To our best knowledge, this the first such tool to calculate the parameters corresponding to certain theoretical model of dielectric relaxation phenomena while the user only need to provide the experimental data. The parameters are calculated by using a nonlinear least square algorithm implemented in Matlab and a nonlinear function minimizer available in Matlab. The way to do the curve fitting is not by the traditional way such as cubic spline but by calculating the simulated data using the chosen model and the calculated result for the parameters. </p> <p> The available mathematical models include all of popular theoretical models, the Cole-Davidson (DC), the Kohlrausch-Williams-Watts (KWW), the Havriliak-Negami (HN) and the model proposed by R. Hilfer (FD). </p> <p> There are two ways to calculate the parameters for each model as mentioned before. The result returned by this system may not be unique. Especially if the frequency range of data is not wide enough, the result would most likely be non-unique. Since the iterative method is used in the system, it is suggested that the user provides the initial values for the system with his best knowledge or background for the data and the tested sample related to dielectric relaxation process. </p> <p> It is normal if there is a part having worse fitting than the other parts. One of reasons could be the mathematical model's defect, which the model does not work for that part. For the further information, please contact me by email at zouhaijun at yahoo.com. </p> / Thesis / Master of Science (MSc)

The conventional Zernike polynomial fit of circular aperture interferograms is reviewed and a more quantitative and statistical analysis is added. Some conventional questions such as the required number of polynomials, sampling requirements, and how to determine the optimum references surface are answered. Then, the analysis is applied to the polynomial fit of noncircular aperture interferograms and axicon interferograms. The problems and limitations of using Zernike polynomials are presented. A method of obtaining the surface figure error information from several smaller subaperture interferograms is analyzed. The limitations of the analysis for testing a large flat, a large parabola, or an aspheric surface are presented. The analysis is compared with the local connection method using overlapped wavefront information. Finally, the subaperture interferogram analysis is used to average several interferograms and to analyze lateral shearing interferograms.

Das Systemverhalten eines Einsteckvorganges und anschließenden Haltevorganges soll bestimmt werden. Bei den zu untersuchenden Komponenten sollen die Einpresskraft und die Haltekraft einem gewünschten Systemverhalten entsprechen. Zur Einstellung des gewünschten Systemverhaltens werden die Geometrieparameter variiert. Zuvor wird das Werkstoffverhalten der Komponenten kalibriert. Die vorliegende Spannungs-Dehnungs-Kurve aus einem Zugversuch wird benötigt zur Beschreibung eines Werkstoffverhaltens. Bei dieser Fragestellung geht es um die Parameteridentifikation für ein nichtlineares Materialmodell aus Ansys Workbench. Die Ergebnisse der Zugversuche werden als Referenzsignale in das Signal Processing eingelesen. Die in diesem Materialmodell vorhandenen Materialparameter sind so anzupassen, dass die numerischen Ergebnisse möglichst gut mit den experimentell gewonnenen Daten aus den Versuchen übereinstimmen.

To improve efficacy in the field of drug discovery simpler in vivo, non invasive methods such as PET and SPECT are used. Pharmacokinetic analysis is the underlying method for analyzing the PET data. Imaging of tracer distribution is used to study a metabolic process. Using Matlab as the programming language, a software tool is developed to analyze the quantitative information from PET and to obtain an estimate of pharmacokinetic parameters, representing the bio- distribution of the radiotracer. A Graphical User Interface developed allows two types of analysis, depending upon the nature of the radiotracer: Compartmental Modeling and Logan Plot Analysis. Compartmental analysis gives us rate constants and blood volume where as Logan analysis gives us the distribution volume as the parameter of interest. Code validation is done for two radiotracers, 15O-water (Single compartment model) and FPAC (Logan Plot). Results from the code were compared with those obtained during a research work done to study MDR.

Os potenciais evocados têm uma consagrada utilização em clínica. Sua obtenção é dificultada pela presença de outros sinais biológicos, de artefatos de movimento, de ruído eletrônico, de interferência da rede elétrica e de artefatos de estímulo. A média síncrona ou promediação é um método que elimina os sinais que não estejam sincronizados com a estimulação, incluindo os outros sinais biológicos, os artefatos de movimento, o ruído e a interferência. No entanto, esse método não consegue eliminar os artefatos de estímulo. Outros métodos devem ser usados para essa tarefa. Para esses métodos, a eliminação do artefato de estímulo é bem sucedida quando o artefato não se sobrepõe ao potencial evocado. Porém, para uma captação próxima ao local de estimulação, a sobreposição ocorre e dificulta a eliminação do artefato de estímulo. O objetivo deste trabalho foi o de estudar a variação da amplitude e latência do pico do potencial evocado e sua influência nas estimativas da amplitude, da latência e do erro quadrático médio. Para potenciais evocados em que houve sobreposição com o artefato, o erro médio quadrático sempre foi reduzido com a remoção do artefato de estímulo. O erro de medição da latência foi reduzido a praticamente zero, independentemente da amplitude do potencial evocado. Por outro lado, o método inseriu erro na medição da amplitude de potenciais evocados grandes. Por isso, nesse caso específico de atraso pequeno e amplitude grande, a medição da amplitude deve ser feita diretamente no sinal antes da remoção do artefato de estímulo. Comparando a ocorrência de sobreposição com os locais de captação do potencial evocado, pode-se afirmar que, para o modelo de artefato de estímulo usado neste trabalho, a necessidade de se aplicar o procedimento de remoção de artefato se restringiu aos potenciais evocados captados no cotovelo, para estimulação do nervo mediano tanto no punho quanto na mão. / Evoked potentials have been used in clinics. Their measurement is hindered by the presence of other biological signals, movement artifacts, electronic noise, power-line interference, and stimulus artifacts. Synchronous averaging is a method that eliminates the signals that are not synchronized with the stimulation, including other biological signals, movement artifacts, noise and interference. However, this method fails to eliminate stimulus artifacts. Other methods must be used in this task. Using these methods, one can obtain success in the stimulus artifact elimination, whenever the artifact does not superimpose with the evoked potential. Nevertheless, for a measurement close to the stimulation site, the superimposition is a fact that hinders the elimination of the stimulus artifact. The objective of this Masters thesis was to study the variation of the amplitude and latency of an evoked potential and verify their influence on the amplitude and latency estimates, as well as on the mean square error. For evoked potentials in which there was superposition, the mean square error was always reduced by the removal of the stimulus artifact. Latency measurement errors were reduced to zero, regardless of the evoked potential amplitude. However, this method inserted amplitude measurement errors for large evoked potentials. So, in the case of short delays and large amplitudes, amplitude measurements should be performed directly on the signal, before stimulus artifact removal. By comparing the presence of superposition with the evoked potential recording sites, one may state that, for the stimulus artifact model used in this work, the need to apply the artifact removal procedure was restricted to the evoked potentials recorded on the elbow, for median nerve stimulation both on wrist and hand.

This thesis reflects two advances in atomic force microscopy. The first half is a new lateral force calibration procedure, which, in contrast to existing procedures, is independent of sample and cantilever shape, simple, direct, and quick. The second half is a high-throughput method for processing, fitting, and analyzing force curves taken on Pseudomonas aeruginosa bacteria in an effort to inspire better care for statistics and increase measurement precision.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Jeremy Howard Nussbaum. / B.S.

Determinar curvas a partir de uma série da pontos é uma tarefa importante e muito utilizada em CAD. Este trabalho propõe um algoritmo para determinar uma curva aproximadora representada por diversas curvas de Bézier em sequência a partir de uma sequência de pontos. É utilizada uma abordagem de curvas de Bézier por trechos, onde cada trecho possui continuidade C1-fraca. A otimização é feita pelo recozimento simulado com vizinhança adaptativa que minimiza a soma das distâncias de cada ponto da sequência à curva aproximadora e utiliza o comprimento da curva aproximadora como um fator de regularização. Adicionalmente, é utilizado o recozimento simulado multi-objetivo que avalia a influência da soma das distâncias de cada ponto à curva e do comprimento da curva separadamente. Também é feita uma comparação entre a técnica de ajuste de curvas e a técnica de interpolação de curvas. / The task of determining a curve from a set of points is very important in CAD. This work proposes an algorithm to determine a sequence of Bézier curves that approximate a sequence of points. The piecewise Bézier curve is used, where each curve has C1- weak continuity. The optimization is done using the simulated annealing with adaptive neighborhood aiming at minimizing the sum of the distances from each point of the sequence to the generated curve. The length of this curve is used as a regularization factor. In addition, it is used a multi-objective simulated annealing that evaluates the influence of the sum of the distances from each point to the generated curve, and the curves length. It is also done a comparison between curve fitting and curve interpolation techniques.