• Proceedings of the CALSEC Conference
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• 1999.07a
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• pp.277-299
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• 1999

Since Chrysler Motor Co. had experienced the digital development system in the beginning of 1990's, most of leading automobile companies are trying to apply a digital information system for their own business process reengineering based upon concurrent engineering system from product planning phase. This is called as virtual DMU(Digital Mock-Up) system instead of the traditional PMU(Physical Mock-Up) system. By using the virtual prototype, all of the design requirements and system specifications can be checked, changed and optimized more quickly and more efficiently. This paper consists of five chapters for the DMU information system. In the 1$^{st}$ chapter, the principle of digital design system is suggested by using four basic modules such as product design module, process design module, manufacturing system design module and central control module. The basic scheme of DMU is introduced with the benefits of application in the chapter 2. In the chapter 3, a digital design process of new car development is explained with the detailed DMU design and design review processes. In the chapter 4, the practical DMU manufacturing techniques and applications are introduced as CAD/CAM analyses, DPA(Digital Pre-Assembly)reviews for development, production, operation and maintenance phases, digital tolerance analyses and digital factory analyses for assembling line simulation, automated robot welding processes, production jig ＆ fixtures and painting process simulation. Finally, the activities of digital design support; CAS-styling, CAE-engineering and CAT-testing are summarized for design optimization in the chapter 5. As today's automobile manufactures and related business organizations are struggling to compete in the global marketplace, they are concentrating on efficient use of DMU information system to reduce the new car development cost, to have shorten the delivery schedule and to improve product design quality. To meet the demand of those automobile industries on digital information systems, the CALS(Computer aided Acquisition and Logistics Support) and EC(Electronic Commerce)initiative has been focused as a dominant philosophy in defense ＆ commercial industries, specially automobile industries.s.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1260-1283
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• 2019

Low earth orbit (LEO) satellite broadband network is a crucial part of the space information network. LEO satellite constellation design is a top-level design, which plays a decisive role in the overall performance of the LEO satellite network. However, the existing works on constellation design mainly focus on the coverage criterion and rarely take network performance into the design process. In this article, we develop a unified framework for constellation optimization design in LEO satellite broadband networks. Several design criteria including network performance and coverage capability are combined into the design process. Firstly, the quality of service (QoS) metrics is presented to evaluate the performance of the LEO satellite broadband network. Also, we propose a network stability model for the rapid change of the satellite network topology. Besides, a mathematical model of constellation optimization design is formulated by considering the network cost-efficiency and stability. Then, an optimization algorithm based on non-dominated sorting genetic algorithm-II (NSGA-II) is provided for the problem of constellation design. Finally, the proposed method is further evaluated through numerical simulations. Simulation results validate the proposed method and show that it is an efficient and effective approach for solving the problem of constellation design in LEO satellite broadband networks.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.12-21
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• 2004

Modem society is information oriented with countless people needing quick reliable information. They also wart to be freed from the limitations of reality such astime and space and experience the world of imagination as if it was reality. Design is creating something out of nothing which has an innate sense of virtual within it. Since it is a process of bringing an imagingnation or an image to life, it can be described as the realization of virtuality. there are many ways in which computer adapted methods were utilized for design up to now. With the advance of computers, the process of desinging became efficient, visually complex and much easier. Undoubtedly, computer is a powerful hardware an design and furthermore, find a way to maximize the presence and to actively incorporate this in designing. The virtual reality system can be widely applied to environmental design to provude a high quality design and enhance the feeling of reality through imitation experiments. Computer simulation such as virtual reality systems is expected to be used widely in environmental design.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1750-1752
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• 1999

An active-matrix liquid crystal display (LCD) using thin film transistors (TFTs) has been widely recognized as having potential for high-quality color flat-panel displays. Pixel-Design Array Simulation Tool (PDAST) was used to profoundly understand the gate signal distortion and pixel charging capability, which are the most critical limiting factors for high-quality TFT-LCDs. Since PDAST can simulate the sate, data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the new set of capacitance models on the pixel operations can be effectively analyzed. The set of models which is adopted from VLSI interconnections calculate more precise capacitance. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.309-319
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• 2016

This paper presents a new recognition and classification method for power quality (PQ) disturbances on the basis of pattern linguistic values. This method solves the difficulty of recognizing disturbances rapidly and accurately by using fuzzy logic. This method uses classification disturbance patterns to define the linguistic values of fuzzy input variables and used the input variables of corresponding disturbance pattern to set membership functions. This method also sets the fuzzy rules by analyzing the distribution regularities of the input variable values. One characteristic of this method is that the linguistic values of fuzzy input variables and the setting of membership functions are not only related to the input variables but also to the character of classification disturbance and the classification results. Furthermore, the number of fuzzy rules is equal to the number of disturbance patterns. By using this method for disturbance classification, the membership function and design of fuzzy rules are directly related to the objective of classification, thus effectively reducing the complexity of the design process and yielding accurate classification results. The classification results of the simulation and measured data verify the feasibility and effectiveness of this method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.271-277
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• 2006

Injection molding process is the manufacturing process that can obtain a high quality products in large quantity to a low cost. Since there are many input factors in every situation that can influence part's quality, the method is difficult to save the exact simulation data. Latest, it deals with the CAE method that supports the experiment, it is applied to the Design of Experiment for the optimum injection molding process. If there are many factors, the interaction among those factors must be considered by applying Design of Experiment which is taken from the technique of minimizing the number of experiment. Without a real test, it is taken the simulation data using $Moldflow^(R)$ software. $Moldflow^(R)$ is used for the analysis of injection molding process, it is analyzed the factors that affect a warpage using the Taguchi method and then the optimal injection molding process is obtained.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.5 s.120
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• pp.530-538
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• 2007

An inductor library for efficient low cost RFIC design has been developed based on a standard digital 0.18 ${\mu}m$ CMOS process. The developed library provides four structural variations that are most popular in RFIC design; standard spiral structure, patterned ground shield(PGS) structure to enhance quality factor, stacked structure to enable high inductance values in a given silicon area, multilayer structure to lower series resistance. Electromagnetic simulation, equivalent circuit, and parameter extraction processes have been verified based on measurement results. The extensive measurement and simulation results of the inductor library can be a great asset for low cost RFIC design and development.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.289-289
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• 2009

Light emitting diode(LED) has many advantages including lower energy consumption and longer lifetime and eco-friendly in comparison with traditional light sources. Spheric plastic lens generally used in LED lighting occurs aberration and ghost image which give displeasure and deteriorate vision quality in human eyes. Using the optical program (LightTools$^{TM}$, CodeV$^{TM}$), we were confirm the aberration and ghost image in optical simulation and employed aspheric lens form in the lens design to improve these problems. From the comparison of the simulation results between the aspheric lens and the spheric lens, we were ascertain to be improved both aberration and Ghost image.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.354-357
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• 2005

When Ti-6Al-4V is used in long steam turbine blades, the main issues are how to improve the fatigue strength as a problem of internal quality and how to forge the thinnest possible blades as problem of dimensional precision. To assure an excellent fatigue strength, it is important to make the two phase fine and equiaxial structure by providing enough plastic deformation in the two phase$(\alpha\;phase/\beta\;phase)$ temperature region. Accordingly, it needs to predict that forging temperature, preform design and forging velocity in forging process. To achieve this end, the two steps forging process was suggested to forge the thin and twisted blades with a precision hammer considering die forces and metal flow. Two steps forging process consists of the flattening forging process and finishing forging process. Process in forging of a 1016mm long steam turbine blade is designed by the finite element method. This study attempts to derive systematic design procedures for process design in the forging. Forging parameters was analyzed in two-dimensional plane-strain simulation and two steps forging process carried out in three-dimensional simulation. Consequently, optimal forging process parameters of long steam turbine blades in Ti-6Al-4V with a high dimensional precision are selected in the hammer die forging.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.5
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• pp.84-89
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• 2001

The alignment of the rollers carrying the web is found to be one of important factors to the lateral behavior of the moving web and to the quality of the final web products. But, the perfect alignment of the rollers is not always possible and the web itself can be cambered. Thus the control of lateral behavior of the moving web is critical in the most of web handling systems. The web guiding system that adjusts the angle of the alignment between two adjacent rollers is commonly used in industry. But, in this paper a new web guiding system is proposed by using the lateral dynamics of the moving web induced by a tilted roller in normal direction of a web. The computer simulation study was carried out to verify the steering performance of the suggested guiding system. Computer simulation study shows that the performance of the new guiding mechanism is better than that of an existing guiding mechanism.