This thesis aims at investigating the technologies of the active power-factor correction (PFC) circuit. The system originally in the article is based on a boost converter circuit as the structure, the control method is to adopt the average current mode. We doesn¡¦t only narrate the circuit principle of the systematic circuit in the article but also use the OrCAD PSpice A/D software to simulation. Finally, we implemented make a prototype circuit and verified the proposed method. The experimental result shows that it can reach the goal for the power-factor correction.

Dielectric waveguides are important passive devices in optical communication systems. Circular-core fibers with slight ellipticity may lead to polarization-mode dispersion. A clear understanding of the propagation characteristics of the elliptical fibers thus becomes important for theoretical as well as practical purposes. Although mesh-dependent methods such as the finite-element method or finite-difference method, can be used to study such a complex structure, its computational task is very high. Strictly speaking, mesh-based solution does satisfy the Helmholtz equation and the solution only provided four to five significant digits. On the other hand, the highly accurate solution based on solving the Helmholtz equation of the elliptical coordinate system spend most its computational resources on computing the functional value and the zeros of the modified Mathieu functions of the first kind. Our method is based on linear combination of the exact mode-field solutions of the dielectric optical fiber. We apply the analytical continuity principle to obtain the simultaneous equation of the expansion coefficient vector. Since each basis solution satisfies the Helmholtz equation exactly, the overall solutions are very accurate and provide more than six significant digits for fibers with small elliptical eccentricity. In addition, only the Bessel functions are needed in our computation. Using cylindrical coordinate and symmetry, together with ACM principle, we simplify the problem of modal analysis of dielectric elliptical waveguides. This method also can be applied to some regular polygonal dielectric waveguides such as the large area VCESL.

Based on the Lyapunov stability theorem, a methodology of designing an adaptive sliding mode control (ASMC) scheme is proposed in this thesis for a class of linear dynamic systems with matched and mismatched perturbations. Firstly, by utilizing a pseudo control input in the design of a novel sliding surface function, one can not only suppress the mismatched perturbations in the sliding mode, but also achieve the objective of output tracking. In addition, the accuracy of output tracking can be adjusted through the designed parameter embedded in this pseudo controller. Then, a sliding mode controller is derived to guarantee the existence of the sliding mode in a finite time by using adaptive mechanism, which is used to overcome the lumped perturbations so that the upper bound of perturbations is not required. Finally, two illustrative examples are given to demonstrate the validity of the results.

Tremendous interest to the study of guided waves in pipe inspection in the oil, chemical, and power generating industries has peaked during the last decade. Since the advantages are inspecting long lengths of pipe quickly and without removing insulation. Recent researches in defects inspection are determined by reflection coefficients from the cracks. However, the purpose of this thesis is to excite at a single probe position and to receive the signals of guided waves with the form of loops. For the variations of wave profiles of guided wave, this thesis aimed at the largest energy distribution of wave profiles to proceed with the researches of mode conversion phenomena caused by defects. This thesis utilizes the partial loading source, and excites the non-axisymmetric and axisymmetric guided waves individually along the carbon steel pipes with circumferential defects and without defects to contrast and analyze. According to the change of wave profiles, we can find the variables that change wave profiles for different guided waves modes include propagating distance and frequency, and these cause that the circumferential energy distribution will change. For the non-axisymmetric guided waves in this thesis are non-dispersive, and its variations of phase velocity and group velocity are small, so the variations of wave profiles are also small. Moreover we study the mode conversion phenomena caused by defects from its position which the circumferential energy is largest. It also investigates new modes from mode conversion phenomena produced by defects more completely. Finally, we can predict the types and the number of new modes from mode conversion phenomena by phase velocity dispersion curve, and compare with the experiments well.

Based on the Lyapunov stability theorem, a methodology of designing a decentralized multi-surface adaptive sliding mode control scheme is proposed in this thesis for a class of large-scale nonlinear systems with mismatched perturbations and interconnections. By utilizing the sliding mode control technique, the designed decentralized robust controller with adaptive mechanisms embedded enable the output of each subsystem to track its own desired output signal, and stabilize the whole large-scale system as well as each subsystem at the same time. In addition, the accuracy of output tracking can be adjusted through the designed parameter embedded in the controller. The purpose of the adaptive mechanisms included in the controller is to adapt the unknown upper bounds of perturbations and interconnections. Finally, two illustrative examples are given to demonstrate the feasibility of the proposed methodology.

A mode locked fiber-ring laser utilizing an optical spot-size converter (OSSC) integrated electroabsorption modulator (EAM) and Erbium-doped fiber amplifiers (EDFA) is demonstrated in this work. By taking advantage of OSSC, the EAMs not only have high-speed performance, but also have high tolerance alignment stability and high power handling capability due to the distributive effect. Thus, by the saturation absorbing and highly nonlinear transmission properties of such EAMs, it can be realized that short optical switching widow operations with high pulse energy excitation driven by EDFA can be used to hybrid mode locked ring laser application. The repetition rate of 10GHz in the mode locked fiber-ring laser is set by a RF synthesizer to driven EAM, creating short time gating widows. EDFA with an optical filter of bandwidth 1.2nm is used for optical gain. By adjusting the operation point in EAM to a bias of 1.72V and a RF-power of Vpp=2.2V, a nearly transform-limited autocorrelated Gauss pulse of 11.72ps (FWHM, the extracted pulsewidth is 8.28 ps) with average power level of 1.2mW is obtained. The time-bandwidth product is 0.478. The optical pulsewidths are mainly limited by the optical filter. Without any feedback circuit, pulse jitter of 993fs measured from a high-speed sampling scope (Agilent 86100A, bandwidth =30GHz) is found from the mode locked pulses, indicating the hybrid mode locked operation can be achieved by the EAM saturation absorbing properties. By measuring the photocurrent of EAM, the highest photocurrent occurs in the conditions of the highest optical transmission and also the shortest optical pulses, suggesting the saturation absorbing of EAM is the main mechanism dominating mode-lock operation. The mode locked operation with repetition rates of 10GHz to 20GHz are also obtained, indicating high-speed operation can be boosted from OSSC integrated EAM to hybrid-type mode locked fiber-ring laser.

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Abstract A simple design methodology of robust adaptive sliding m de utput tracking controllers for a class of MIMO nonlinear mismatched perturbed systems is presented in this thesis.First,the derivatives of tracking error

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Over the past years, the rapid transformation in social vironment and the vigorous political development have stimulated the public to raise their demand for the government¡¦s administration and service quality. In order to elevate administrative effectiveness, increase competitiveness,and satisfy the public¡¦s demand for service quality, the government has undergone government renovation, the implementation of ¡§electronic government¡¨being part of this movement. Household administration, tax collection, traffic administration, and land administration are examples of computerization. Moreover, because the government budget is limited and affairs of land administration are complicated, it took more time to computerize land administration affairs. However, it has been implemented for some time, and the ¡§effectiveness¡¨is to be evaluated. ¡@¡@This study was to evaluate the effectiveness and quality of the service rendered by the Land Affairs Administration of Kaohsiung County after it implemented computerization. There are various scale methods which can be used to evaluate performance and degree of satisfaction. This study adopted the PZB model, proposed by Parsuraman, Zeithaml and Berry¡]1985¡^to analyze the differences in the cognition of service quality among the public, land administration supervisors, and employees. The finding would serve as scientific foundation for the land affairs administration to improve its service quality. The major finding was classified into four categories: (1) Some of the 25 survey items in Gap 1 and Gap 2 of service quality were rejected, (2) All the 25 survey items in Gap 3 and Gap 5 of service quality were rejected; (3) The satisfaction gap of the public was larger than that of paralegal service and brokers, (4) After examining the variance of sex, age, and education of the public, it was found that age was the most powerful varable. ¡@¡@This study found that the land administration supervisors obtained higher average scores on emphasizing service quality than those obtained by their public and employees counterparts, indicating that the supervisors attached more importance to service quality than the other 25 survey items, indicating that the administration should work hard to make things better. In addition, the public¡¦s mean score of satisfaction the brokers, indicating that the public were less satisfied than the paralegal service with the service quality offered by the land administration. This could be caused by the public¡¦s unfamiliarity with land administration laws and operating procedures, and has produced the differences in the cognition of service quality. The land affairs administration should pay attention to this phenomenon. The performance of land affairs administration offices should be evaluated based on the viewpoint of the public in order to provide service that meets the public¡¦s expectations. To remove all the gaps is what land affairs administration offices should do first in order to improve their service quality.