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The subject is to study two-dimension phase transition. The nano-magnetic particles dispersed in magnetic fluid can aggregate to form magnetic columns under external perpendicular magnetic field. At some appropriate condition, these magnetic columns are able to form two-dimension lattices. It is a novel mesoscopic system for studying two-dimensional melting transition. By controlling external magnetic field, we explore phenomena of phase transition and defect dynamics. This article can be divided to three parts. In the first part, we study the phase transition with two-dimension lattice forming with magnetic fluid, then we classify the crystal, hexatic and liquid phases in the melting process with translational correlation function and bond-orientational correlation function. In the second part, we analyze the defect dynamics within the lattice with Burgers Vector. In the third part of this article, the external DC magnetic field is replaced with the AC magnetic field, we find that the two-dimension lattices are also formed in low frequency region. The relationship between the two-dimension lattice forming and the AC frequency are studied.

The purpose of this project is to design a computer program to help children understand a strategy for changing vantage points within an imagined space and gain knowledge of how spatial transformations work. The developed software, called Viewpoints, presents a virtual three-dimensional environment to be explored and modified by the user. Object and camera manipulations are illustrated through animation. Furthermore, the program was designed to have an intuitive interface and be easy to access. This should allow the software’s target audience of children to focus on the spatial orientation and spatial visualization aspects. A small study evaluated the software in terms of content, instructional design, technical quality, student use, and instructor use. The study provided valuable feedback on how to improve Viewpoints in the future. Information gathered suggests the issue of speed should be addressed and supplemental materials should be added.

Eddy current testing is a widely-used examination of the nondestructive testing method. According to the theory of electromagnetic induction, the coil impendence varies with the interaction between the coil magnetic field and the eddy current magnetic field. By observing the variations of the phase angle and the impendence plane diagram, the influence of different defects and factors are evidently presented. The purpose of this study is to analyze the three-dimensional defects of eddy current testing by means of the finite element method. To begin with, a complete 3-D electromagnetic model in eddy current testing by finite element software package COMSOL Multiphysic was created. Then the impendence plane diagram and evaluation curves are drawn by the mathematics software package MATLAB to show the variations of the impendence and the phase angle. Moreover, the results show the effect of reducing testing errors. The simulation of 3-D defect model can provide more comparable data for experimentalists. So that the problem of inappropriate judgement can be prevented, and then the accuracy in eddy current testing can be enhanced.

This thesis includes two topics. The first topic is an ADFS¡]All Digital Frequency Synthesizer¡^using a Flying Adder architecture. The second one is a low-power and low-latency 2-dimensional bypassing signed multiplier. In the first topic, the ADFS is implemented by only using the standard cell library of TSMC¡]Taiwan Semiconductor Manufacturing Company¡^0.18 £gm 1P6M CMOS process. The turn-around time is effectively reduced. Furthermore, the portability and reusability of the proposed design is significantly enhanced. The design provides stable clock signals with fast switching time. In the second topic, the proposed multiplier is carried out by Baugh-Wooley algorithm using 2-dimensional bypassing units. The proposed bypassing units automatically skip redundant signal transitions when either the horizontally¡]row¡^partial products or vertically¡]column¡^operands are zero.

Section Steel usually is a order-oriented production and not easy to resell. The material cost is large percentages of overall production cost. Hence, the key to boost efficient management is to increase the material output rate. In other words, we need to publish a efficient and reasonable cutting plan before production. And the cutting plan can cope with change to meet the market demand. The cutting plan designing is a one-dimensional cutting stock problem, and also is a typical bin packing problem. In this study we examine a combined heuristic approach for this problem. The proposed approach combines two themes of solving method¡Ga neighborhood search algorithm with threshold accepting techniques, and a Branch and Bound method. The performance of the combined heuristic approach was verified by running several benchmarking problems and the results were reported. Experimental results indicate that the proposed solving process can effectively search the feasible region and avoid being trapped in local optimal.

Nahua reservoir is an important water resource for supplying drinking water to the Tainan area and a part of Kaohsiung in Taiwan. In recent years, Nanhua reservoir suffers eutrophication problems as many other reservoirs in Taiwan. In order to study eutrophication problems in reservoirs, a three-dimensional hydrodynamic and water quality model has been constructed using the FVCOM (Finite Volume Coastal Ocean Model) model to simulation the hydrodynamics, the nutrient dynamics and the phytoplankton growth in the Nanhua reservoir. The modeling of 3D hydrodynamics is the basic module dominating the circulation in the reservoir. The 3D eutro-dynamics are also calculated by the water quality module, which includes the dynamic variations of chlorophyll-a (Chl-a), dissolve oxygen (DO), carbon biological oxygen demand (CBOD), ammonia nitrogen (NH3-N), nitrate nitrogen (NO3-N), organic nitrogen (ON), phosphate (PO4) and organic phosphorus (OP). The model was first calibrated with the data measured in 2007 and, then, verified with the 2008 data. The model results are in reasonable agreement with the field measurements, both in the calibration and the verification phases. The water level variations are influenced by daily supply for the drinking water treatment and the inflows from the catchment and from Chiashian aqueduct during the dry season in spring. Nutrients are mainly carried into the reservoir through these routes. The residence time in the reservoir and the phytoplankton response with the nutrient loads are calculated. The model results indicated that phytoplankton growth is limited by low temperature and long residence time during the winter. The chlorophyll levels are getting higher from spring through out summer, which is due to enough sun lights and high nutrient loads carried by the catchment runoff. Surface temperatures are higher then the bottom layers causing stratification that worsen the eutrophication problems. Besides the comparisons by hydrodynamic and water quality parameters, the Carlson Trophic State Index (CTSI) has been calculated to categorize the eutrophication levels in the reservoir, which have shown good agreement with the CTSI calculated from EPA sampling data. Therefore, the model can be used as a tool for water quality management in the Nanhua reservoir.

<p>Nowadays, business intelligence techniques are applied more and more often in different settings including corporations and organizations both in the private and public sector. It is really a broad field which can assist business people to realize the state of their organization and make profitable decisions.</p><p>In this thesis, I will focus on one of its components, data warehouse, by proposing activity theory as the method to solve the dimension identification problem in data warehouse. Under the background of project IMIS and the involved personnel, who determine the dimension, firstly I study how to use the ER method, “bottom up” method, and activity theory method to identify the dimension in data warehouse, and some relevant knowledge about the three methods. Then, we apply the three methods to identify the dimension. After that, I evaluate the dimension identification results of the three methods according to the feedback from the healthcare organization to get their veracity and integrality. Finally, based on the results of my efforts, I arrive to the conclusion that the activity theory method can be applied to identify the dimension in data warehouse, and with the comparison to the other two traditional methods (ER model and “bottom up”), the activity theory method is more easy and natural to identify the dimension of a dimensional model.</p>

Techn. Univ., Diss.--Wien, 2007.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 71-78). Also available on the Internet.