• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1943-1950
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• 2009

The development of high voltage Insulated Gate Bipolar Transistor (IGBT) have given new device advantage in the areas where they compete with conventional GTO (Gate Turnoff Thyristor) technology. The IGBT combines the advantages of a power MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) and a bipolar power transistor. The change of electrical characteristics for IGBT is mainly coming from the change of characteristics of MOSFET at the input gate and the PNP transistors at the output. The gate oxide structure gives the main influence on the changes in the electrical characteristics affected by environments such as radiation and temperature, etc.. The change of threshold voltage, which is one of the important design parameters, is brought by charge trapping at the gate oxide. In this paper, the electrical characteristics are simulated by SPICE simulation, and the parameters are found to design optimized circuits.

• 전기의세계
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• v.29 no.10
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• pp.653-659
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• 1980

The paper describes a new technique for the shape design of a bell-type porcelain locke insulator in contaminated environment. Early studies on the contamination performance of insulators indicated the need for an improvable shape to provide adequate insulation strength at normal operating voltages. In this paper, under lightly and heavily contaminated site severity, the variation of voltage distribution to leakage path at insulator surfaces analyzed by the complex admittance matrix using finite element method. By this results, the improvement of shape of insulators could be approached to the available condition in contaminated environments. In applicating to compare a standard disc type with a fog disc type insulator, this design technique is valid.

• English Language & Literature Teaching
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• v.10 no.1
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• pp.127-152
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• 2004

The purpose of this study is to elaborate design strategies for a Web-based self-directed cooperative distance language learning community. Research was done regarding the theoretical foundations for self-directed cooperative language learning and Web-based learning communities. The components of a Web-based community for self-directed cooperative language learning system are also investigated. As a result of this study, design strategies for Web-based communities are suggested. There are performance and supporting environments(synchronous/asynchronous) for self- directed cooperative language learning. There are also cultural experiences and communication factors in the performance field. Furthermore, matching communicators, finding and offering information, language learning content and other supporting agents are important in the supporting environment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.67
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• pp.49-60
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• 2001

Data warehouse(DW) manages all information in a Enterprise and also offers the specific information to users. However, it might be difficult to develope an effective DW system due to varieties in computing facilities, data base, and operating systems. The heterogeneous system environments make it harder to extract data and to provide proper information to usesr in real time. Also commonly occurred is data inconsistency of non-integrated legacy system, which requires an effective and efficient data extraction flow control as well as data cleansing. We design the integrated automatic ETT(Extraction Transformation Transportation) system to control data extraction flow and suggest implementation methodology. Detail analysis and design are given to specify the proposed ETT approach with a real implementation.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.1
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• pp.16-22
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• 2009

This paper aims at designing an impulse-radio ultra-wideband (IR-UWB) transceiver, especially targeting the IEEE 802.15.4a indoor ranging and communication systems. We first investigate the IEEE 802.15.4a IR-UWB signals and suggest the full-digital transceiver architecture accordingly. Since the wireless systems equipped with the impulse signal have the property of low-duty cycle, i.e., discontinuity in time, while the conventional systems takes the continuous signals, it is required to reconfigure the system design, including link budget. Following brief introduction to our IEEE 802.15.4a IR-UWB system hardware, we finally examine the ranging performance in indoor environments to verify our system design.

• Journal of the Korea Society for Simulation
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• v.6 no.1
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• pp.25-40
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• 1997

This study deals with an autonomous generation of simulation codes for the design of processes of c CIM system based on the concept of model transformation. We assume we have a functional model of an organization which is developed using the well-known IDEF0 methodology. Then, a modeling methodology, called PROWD(PRocess flOW Description), is suggested to develop the flow processes of the organization. To Derive simulation specifications for the transformed PROWD model, we define a module of a "unit system" for each activity of PROWD model. Then specifications for system entities and resources are derived from input/control/mechanism/output and entity flows of PROWD model. Entitiy queues are defined from the sates and events of unit systems. Finally, SIMAN model frame is generated from those specifications through a suggested algorithm. The implementability and validity of the proposed approach is tested by developing a prototype of a computer-assisted design system on the operation processes of FMS installed at SNU-ASRI (Seoul National University-Automation and Systems Research Institute).nstitute).

• Proceedings of the Korean Institute of Interior Design Conference
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• 2008.05a
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• pp.93-96
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• 2008

The childhood reading and physical environments are an important factor for shaping personality and values established. Therefore, We have to provide a quality environment for correct reading habits to children. the purpose of this study is to provide a basic interior data through the analysis of case study. for this purpose this study has analyzed of 5 children's reading room of public libraries built in Seoul since 2000. especially the research which it analyzed these reading room of forms of space, furniture, color, finish material, lighting. the results of this study are follows : Chairs and desks were not considered of children's scale or uniformly made. compositions of convenient facilities has insufficient component. finish material and lighting plan is similar to adults reading room plan. To give correct reading habits and interest to children, considered space design is necessary.

• IE interfaces
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• v.13 no.4
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• pp.725-737
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• 2000

This paper deals with the design and the development of user interface for a high speed linear programming solving system. The general users' educational and practical requirements are analyzed and the functionalities that should be implemented for the requirements are designed. The user interface of the system consists of various carefully designed built-in commands that perform the functionalities. The names of the build-in commands are chosen to enhance the users' convenience. We also address the various factors that should be considered in the design of the linear programming solvers when integrated with the user interface. As one of user-friendly environments, data input system that can understand user-written arithmetic form is added to our user interface system. Finally, we compare our system with other user interface systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.5
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• pp.612-617
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• 2016

A motorcycle frame is a structure that endures the load and retains durability under various driving environments. A motorcycle has been developed with a diverse utility range, and its design has always been expanded to the newly created concept based on advanced engineering technologies. In this study, a compact motorcycle frame is considered to perform parametric studies that can enhance the stiffness of a frame with computational simulation. Finite element analysis is used to compare the deformation and stiffness of a base model and four case-models with three design-change-parameters. The parametric studies are analyzed to provide available methods that can be expected in the industrial fields of engineering design for a motorcycle frame.

• IE interfaces
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• v.6 no.2
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• pp.19-35
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• 1993

This paper presents the development of a knowledge-based expert system to assist for designer in the process of designing products for easier assembly. The developed expert system for supporting assembly-oriented product design, which is named as DFA-MASTER, consists of two subsystems such as "Assembly Method Selection System" which provides feasible assembly methods to designer and "DFA-Analysis System" which provides guidelines to improve assemblability of products in the early stage of product design. The developed system is interfaced with AutoCAD system and can be run under PC environments. By using DFA-MASTER, designer can obtain feasible assembly methods which have high assemblability under the given asssembly conditions and also evaluate the assemblability of part feature or product structure.