This thesis describes the development of a red tip/tilt and fringe detection system at the Sydney University Stellar Interferometer (SUSI), modelling the instrumental performance and effects of seeing at SUSI, making observations of Mira variable stars and finally modelling the atmospheres of Mira variables with physically self-consistent models. The new SUSI tip/tilt system is based around a CCD detector and has been successfully used to both track the majority of tip/tilt power in median seeing at an R magnitude of 4.5, and to provide seeing measures for post processing. The new fringe-detection system rapidly scans 33 to 140 $\mu$m in delay and detects the fringes using two avalanche-photodiodes. It has been used to acquire fringe data, provide user feedback and to track the fringe group-delay position. The system visibility (fringe visibility for a point source) and throughput were found to be consistent with models of the SUSI optical beam train. Observations were made of a variety of sources, including the Mira variables R Car and RR Sco, which were observed in two orthogonal polarization states. These measurements were the first successful use of Optical Interferometric Polarimetry (OIP), and enabled scattered light to be separated from bright photospheric flux. Dust scattering was found to originate from a thin shell 2-3 continuum radii from these stars, with an optical depth of 0.1 to 0.2 at 900 nm. Physical models of Mira variables including dust formation were developed, providing consistent explanations for these results as well as many other photometric and interferometric observations.

Les progrès dans les techniques de conception et dans la technologie des semi-conducteurs ont permis l'intégration de systèmes embarqués de complexité croissante sur une puce, les systèmes sur puce (System on Chip - SOC). Les piliers de la stratégie adoptée pour atteindre ce résultat sont les suivants: (1) la réutilisation de composants (IP), (2) l'utilisation de plateformes, (3) l'abstraction. L'ensemble de ces techniques permet de concevoir des systèmes complets pouvant répondre aux besoins d'applications complexes et déterministes. Cette situation change si les applications visées sont diverses dans leur comportement à l'exécution en termes d'utilisation de ressources et si de plus chaque application elle même présente un caractère variable à l'exécution. Cette variabilité de la charge de travail va à l'encontre des méthodologies actuelles qui considèrent que toutes les informations relatives aux applications sont connues de manière statique et que donc toutes les décisions de partitionnement logiciel-matériel, et d'allocation de ressources ainsi que d'ordonnancement le sont aussi. Dans cette thèse nous proposons une nouvelle approche pour la conception de systèmes sur puce avec charge variable. Le problème est posé comme un problème de contrôle adaptatif avec prédicteur dynamique de charge de travail. La première partie de la thèse se focalise sur l'extraction automatique des différentes caractéristiques qui favorisent l'introduction d'un aspect adaptatif dans l'architecture d'une application et la résolution du problème de la prédiction de grandes séries de temps résultant de la capture de la variabilité de charge. Nous présentons les réseaux de neurones récurrents connus comme des approximateurs universels capables de modéliser un phénomène dynamique non linéaire et les appliquons à la prédiction dynamique de charge dans les Systèmes sur Puce. Les aspects théoriques fondamentaux ayant été fixés dans la deuxième partie de la thèse nous évaluons le coût en surface de l'implémentation d'un prédicteur par une exploration automatique multiobjective puis évaluons ses performances dans une plateforme SOC modélisée en SystemC TLM. Ces travaux ont été validés sur une application industrielle multimédia JPEG-2000. Il en découle un traitement adaptatif en nombre de ressources résultant en une meilleure efficacité de l'utilisation du circuit et une meilleure performance comparée a une architecture fixe.

The awareness of electric power quality has increased over the past decade as electronic equipment has become more susceptible to power disturbances. The most disruptive power disturbances are voltage sags and momentary interruptions and their effect on adjustable speed drives (ASDs) is studied in this thesis. Several solutions have been suggested to provide only voltage sag ride-through to ASDs, but most solutions focus on ASDs with passive rectifiers since they hold the largest share of the market. This thesis focuses on ASDs with active rectifiers, which is an emerging and growing market due to the advantages of four quadrant operation and reduced harmonics offered. A solution is presented which provides an ASD with an active rectifier with the capability to ride through the most common sags in order to reduce the frequency at which the ASD trips and thereby increase its reliability. In order to provide ASDs with the capability to ride through momentary interruptions, it is necessary to interface an energy storage system to the ASD. Flywheels, ultra-capacitors and batteries are evaluated for use in an energy storage system to provide voltage sag and momentary interruption ride-through and a detailed comparison of six systems based on these technologies is presented. The interface circuit between the energy storage system and ASD has a significant influence on the performance of the energy storage system and therefore interface circuits to ASDs with passive and active rectifiers are studied. The addition of an ultra-capacitor energy storage system to an ASD with an active rectifier in order to provide ride-through of deeper sags and momentary interruptions is studied and a fuzzy logic controller is designed to enhance system performance. Initially, no communication between the ASD and the ultra-capacitor system is assumed and the ultra-capacitor system can therefore be added as a retro-fit to an existing ASD. It is, however, foreseen that the market for ASDs with ride-through capability of voltage sags and momentary interruptions will grow and the concepts for an integrated design of an ASD and an energy storage system are presented. / Graduation date: 1999

The continuing desire of industry to further improve process efficiency, through tighter control and energy conservation, has prompted users to pay closer attention to Adjustable Speed Drives (ASDs). The conventional ASDs consist of induction or synchronous motors controlled by power electronic controllers through the adjustment of supply frequency and line voltage. The drawback of these conventional ASDs lies in the high cost of the power electronic controllers which have the same rating as that of the machine itself. The Brush less Doubly-Fed Machine (BDFM) ASD has proven, both analytically and experimentally, to provide a cost effective and a wide range of precise speed control. The experimental BDFM prototypes built to date were designed and constructed individually based on designers' experience with self-cascaded machines. The success with these prototypes has promoted the idea of standardizing the design procedure for all future BDFMs. This thesis offers a general design procedure for the BDFM, which can serve as a first step in standardizing the manufacturing process of this machine. The procedure is presented in the form of a demonstration, by applying it to the design of a 60-hp, 600 to 900 r/min, 460-volts BDFM pump drive to replace the currently utilized conventional 60-hp wound rotor induction motor ASD. An ideal design, which determines machine details such as physical dimensions, slot specifics and conductor details based on conservative magnetic and electric loading assumptions, is one form of the design procedure. The other form, the practical design, involves utilizing a specified physical dimensions and slot details to determine the associated conductors' details and to insure the compliance of machine loadings with up-to-date industrial standards. In both procedures, the design will be made to satisfy, if not to exceed, the existing conventional drive performance. / Graduation date: 1994

Variable Selection has always been a very important problem in statistics. We often meet situations where a huge data set is given and we want to find out the relationship between the response and the corresponding variables. With a huge number of variables, we often end up with a big model even if we delete those that are insignificant. There are two reasons why we are unsatisfied with a final model with too many variables. The first reason is the prediction accuracy. Though the prediction bias might be small under a big model, the variance is usually very high. The second reason is interpretation. With a large number of variables in the model, it's hard to determine a clear relationship and explain the effects of variables we are interested in. A lot of variable selection methods have been proposed. However, one disadvantage of variable selection is that different sizes of model require different tuning parameters in the analysis, which is hard to choose for non-statisticians. Xin and Zhu advocate variable ranking instead of variable selection. Once variables are ranked properly, we can make the selection by adopting a threshold rule. In this thesis, we try to rank the variables using Least Angle Regression (LARS). Some shrinkage methods like Lasso and LARS can shrink the coefficients to zero. The advantage of this kind of methods is that they can give a solution path which describes the order that variables enter the model. This provides an intuitive way to rank variables based on the path. However, Lasso can sometimes be difficult to apply to variable ranking directly. This is because that in a Lasso solution path, variables might enter the model and then get dropped. This dropping issue makes it hard to rank based on the order of entrance. However, LARS, which is a modified version of Lasso, doesn't have this problem. We'll make use of this property and rank variables using LARS solution path.

.Taiwan is the island country, the exportation value occupies GDP 70%. Taiwan exports many products to the mainland , then these products exports to each place in the world, in which mostly is the European,American and other advanced countries. US is especially important nation to the product demand .Its demand degree is affecting the Taiwan economy deeply. Therefore, when these countries's demand weaken, it will affect Taiwan's exportation situation.And this means global environment and Taiwan's economical growth will be closely linked.However, while the overall environment changes, the enterprises does not just let their companies to go out of business or to rally. Under better mangerment, many enterprises still might passed the crisis safely.This paper discusses if the overall environmental factor changes , under certain governing condition, the occurance of financial crisis will be affected or not. This paper uses Logit and the Probit model.Moreover, we know many traditional papers researched the relationship between financial variables and the financial crisis , and this paper also want to discuss if the financial factor changes , under certain governing condition, the occurance of financial crisis will be affected or not.The related result is as follows: 1. American overall variables, the financial variables and the company govern variables separately affect the occurance of finance crisis . 2.Regarding the research about ¡§If the overall environmental factor changes , under certain governing condition, the occurance of financial crisis will be affected ,¡¨the result shows interactive effects between overall variables and company govern variables do not very remarkable.And Regarding the research about ¡§If the financial factor changes , under certain governing condition, the occurance of financial crisis will be affected ,¡¨the result shows interactive effects between financial variables and company govern variables are more remarkable. 3.Under better corporate governance , besides the financial fluidity, the financial condition is also better.

A study of double-variable-curvature microlenses (DVCM) for promoting coupling efficiency between the high-power 980-nm pumping laser diodes and the single-mode fibers has been proposed. In comparison with the previous works on asymmetric fiber microlenses fabricated by the multi-step processes with complicated fabrication, the advantages of the DVCM structure for achieving high coupling are a single-step fabrication, a reproducible process, and a high-yield output. In the fusing procedure, the slight arc fusion was mainly applied for fine polishing merely instead of reshaping for the reason that the fabricated double-variable-curvature fiber endface (DVCFE) was very close to the ideal shape. Hence, the fabrication time was reduced and the yield was promoted due to the withdrawn step of tip elimination. In this study, the geometric center of the fiber was defined through, the cladding diameter and the core diameter, for comparison to measure the offset. The offset measured by the core diameter was more accurate and coincidence with the coupling efficiency in the experiment. In the fabricated 45 DVCMs, to achieve the average coupling efficiencies higher than 84%, the offsets were ought to be controlled in merely less than 0.6£gm with the curvature radii in the minor axis ranged from 2.4 to 2.9£gm (with tolerance of 0.5£gm). Alternatively, the offsets were ought to be controlled in less than 0.3£gm though the curvature radii in the minor axis ranged from 2.4 to 3.7£gm (with larger tolerance of 1.3£gm). However, it was more difficult to control over the offsets than the curvature radii in the minor axis while fabricating the DVCMs. In conclusion, to achieve higher yield, it was relatively practical to control the offsets of fiber microlenses to be less than 0.6£gm with 2.4 to 2.9£gm curvature radius. As a result, the coupling efficiencies were all higher than 80%.

The objective of this thesis is to develop a low-cost infrared absorption spectroscope based on linear variable filter (LVF) technology for the automated detection of gases and vapors, and the semi-automated detection of liquids. This instrument represents an alternative to electronic-nose instruments based on cross-selective gas sensor arrays. Instead, the proposed instrument uses the idea of computational “pseudo-sensors”, whereby spectral lines in an analytical instrument are clustered into groups and used as independent variables. We characterize the system on a number of performance metrics, uncovering its detection limits and resolving power. We present calibration methods to estimate the concentration of analytes in a matrix of absorbing species, as well as signal processing techniques for spectral classification. Specifically, we validate the instrument on a mixture calibration problem with simple and complex chemicals, and compare the efficiency of different calibration methods to estimate the concentration of one analyte in the matrix. Moreover, we demonstrate the use of the instrument on two real-world applications in the foodstuffs domain: oil adulteration and trans fatty acid (TFA) detection. The instrument, combined with signal processing techniques, is able to fully discriminate oils, as well as classify margarine and spreads onto high-TFA and low-TFA groups. Despite operating at a low spectral resolution, our results show that the LVF based spectroscope is a promising alternative to traditional analytical techniques for selected niche applications.

This thesis is concerned with the designing of an nth order adaptive integral variable structure derivative estimator (AIVSDE). The proposed estimator's scheme is in fact a modified and extended version of the existing AIVSDE. The new proposed AIVSDE can be used as a direct nth differentiator for a smooth signal which has n continuous and bounded derivatives. The adaptive algorithm is utilized for the switching gain to remove the requirement for a priori knowledge about the upper bound of the derivative of the input signal. The stability of the redesigned first order, the second order, and the nth order derivative's estimation is guaranteed by the proposed scheme. An example is demonstrated for showing the applicability of the proposed AIVSDE.

By using Lyapunov stability theorem, a quasi-optimal model reference adaptive control (QOMRAC) scheme is presented in this thesis to stabilize a class of uncertain systems with input nonlinearity. This control scheme contains two main types of controllers. The first type is a linear feedback controller, which is an optimal controller if the controlled systems do not have any perturbations. The second type is an adaptive controller, which is used for adapting the unknown upper bound of perturbation or perturbation estimation error. The property of uniformly ultimately boundness is guaranteed when employing the proposed control scheme, and the effects of each design parameter on the dynamic performance are also analyzed. An example is demonstrated for showing the feasibility of the proposed control scheme.