• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.298-300
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• 1999

컴퓨터 지원 협동작업(Computer Supported Cooperative Work, CSCW)을 실혐시키는 그룹웨어에 대한 연구는 여러 분야에서 활발히 이루어지고 있으나, 공동 프로젝트 수행시 참여자간 의사 소통에 필요한 정보 공유를 위해 효율적인 자료 기록 및 검색에 대한 연구는 미비한 실정이다. 따라서 본 논문에서는 공동 작업시 필요한 자료 공유와 효과적인 검색을 위하여 DBMS 질의를 이용한 자료 기록과 검색 뿐 아니라 규칙 기반의 검색 엔진 설계를 포함하는 지능적인 검색기능을 제공하는 그룹웨어 회의 시스템인 IReRCoS(Record and Retrieval based Conferencing System)를 설계한다. JAVA Applet 인터페이스를 통해 공유 자료 기록 조건과 검색 조건을 입력하고 데이터베이스에 저장된 자료를 MSSQL 질의어 및 JESS의 검색 엔진을 통해 해당 파일을 추출한다. IReRCoS는 지능적인 공유자료 기록 및 검색 기능을 지원함으로써 컴퓨터 기반의 다수가 참여한 공동 작업을 원활히 수행할 수 있는 통합된 그룹웨어 환경을 제공하는 것을 목표로 한다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1976-1977
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• 2007

This paper introduce the electrical quantities of a three-phase-connected wind induction generator (WIG) under sudden connection of static loads. An intelligent power-system recorder/monitor is employed to measure threephase voltages and currents of the studied system at WIG's terminals and load's terminals for 5 minutes. A laboratory 300 W wound-rotor induction machine driven by a blushless DC motor is utilized as the studied WIG. Since the generated harmonic currents are randomly varied, total harmonic distortion (THD) of current using cumulative probability density function is employed to determine the penetration of harmonic distortion. The results show that the harmonic currents generated by the studied WIG may be severely amplified to a high level by the connected self-excited capacitance at the stator's terminals.

• Journal of Electrical Engineering and Technology
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• v.2 no.3
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• pp.300-305
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• 2007

This paper reports an investigation of overvoltages caused by ferroresonance in the distribution system, which consists of a bank of open-delta single-phase voltage transformers. The high voltage sides of the voltage transformer are connected to the distribution system via three single-phase fuse cutouts. Due to the saturation characteristic of the transformer cores, ferroresonance can occur in the condition that the transformer is energized or deenergized with single-phase switching operation of the fuse cutouts. The simulation tool based on EMTP is used to investigate the overvoltages at the high side of voltage transformer. Bifurcation diagrams are used to present the ferroresonance behavior in ranges of different operating conditions. The simulation results are in good agreement with the results from the experiment of 22 kV voltage transformers. The mitigation technique with additional damping resistors in the secondary windings of the voltage transformers will be introduced. Brief discussion will be made on the physical phenomena related to the overvoltage and the damage of voltage transformer.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.188-188
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• 2011

Recently, scaling down of ULSI (Ultra Large Scale Integration) circuit of CMOS (Complementary Meta Oxide Semiconductor) based electronic devices, the electronic devices, become much faster and smaller size that are promising property of semiconductor market. However, very narrow interconnect line width has some disadvantages. Deposition of conformal and thin barrier is not easy. And metallization process needs deposition of diffusion barrier and glue layer for EP/ELP deposition. Thus, there is not enough space for copper filling process. In order to get over these negative effects, simple process of copper metallization is important. In this study, Cu-V alloy layer was deposited using of DC/RF magnetron sputter deposition system. Cu-V alloy film was deposited on the plane SiO2/Si bi-layer substrate with smooth surface. Cu-V film's thickness was about 50 nm. Cu-V alloy film deposited at $150^{\circ}C$. XRD, AFM, Hall measurement system, and AES were used to analyze this work. For the barrier formation, annealing temperature was 300, 400, $500^{\circ}C$ (1 hour). Barrier thermal stability was tested by I-V(leakage current) and XRD analysis after 300, 500, $700^{\circ}C$ (12 hour) annealing. With this research, over $500^{\circ}C$ annealed barrier has large leakage current. However vanadium-based diffusion barrier annealed at $400^{\circ}C$ has good thermal stability. Therefore thermal stability of vanadium-based diffusion barrier is desirable for copper interconnection.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2189-2196
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• 2014

In this paper, a VLIW(Very Long Instruction Word) vision coprocessor which can efficiently accelerate computer vision algorithm for automotive is designed. The VLIW coprocessor executes four instructions per clock cycle via 8-stage pipelined structure and has 36 integer and floating-point instructions to accelerate computer vision algorithm for pedestrian detection. The processor has about 300-MHz operating frequency and about 210,900 gates under 45nm CMOS technology and its estimated performance is 1.2 GOPS(Giga Operations Per Second). The vision system composed of vision primitive engine and eight VLIW coprocessors can execute pedestrian detection at 25~29 frames per second(FPS). Because the VLIW coprocessor has high detection rate and loosely coupled interface with host processor, it can be efficiently applicable to a wide range of vision applications.

• Journal of Sensor Science and Technology
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• v.6 no.2
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• pp.163-171
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• 1997

CdS thin films for window material of solar cell were prepared by close spaced vapor transport deposition system and annealed at different temperatures. The structural, electrical, and optical properties of as-deposited and annealed CdS films were investigated as functions of substrate and annealing temperatures. The CdS thin films were grown perpendicularly to the substrate along the (002)plane with hexagonal structure regardless of the preparation conditions The resistivity of the CdS film deposited was increased gradually from $60{\Omega}cm$ for $25^{\circ}C$ to $2{\times}10^{4}{\Omega}cm$ for $300^{\circ}C$. The optical transmittance at the substrate temperature of $25^{\circ}C$ was about 80% in the the visible spectrum. The resistivity increased monotonically, and the optical transmittance was decreased substantially with annealing temperature due to the increased defect density in the CdS film.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.4
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• pp.87-94
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• 1999

Empirical design is still used to avoid a structural damage because impact phenomenon and structural behaviour due to wave impact load can not examined accurately. The damage due to wave impact load is largely affected by impact pressure impulse and impact load area. The objective of this study is, as the second step, to develop an efficient scantling program of bow flare structure, and to predict its impact load area by comparing maximum dented deformations at center of idealized panel structure model of bow flare structure of 300k DWT VLCC using LS/DYNA3D code, which will be used for its verification of dynamic structural analysis, as the next step. Through this study, the impact load area was estimated as $1.5s{\times}1.5s$ stiffener space(s) in the case of panel with stiffeners and as $2.5s{\times}2.5s$, with stringers, under impact pressure curve with peak height 6.5MPa, tail height 1.0MPa, and duration time 5.0msec.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.298-300
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• 2003

The KSTAR superconducting magnet system consists of 16 TF (Toroidal Field) and 14 PF (Poloidal Field) coils. Both of the TF and PF coil system use internally-cooled Cable-In-Conduit Conductors (CICC). The major achievement in KSTAR magnet system development includes the development of CICC, the development of a full size TF model coil, the development of a background magnetic field generation coil system, the construction of a large scale superconducting magnet. TF and PF coils are in the stage of the fabrication for the KSTAR completion in the year 2005.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3060-3063
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• 1999

We made a multi-layer conveyor sterilizing system using UV rays to prolong a storage period of dried marine products. The system is composed of 5 layer conveyor belt of 3 m long each, thus 15 m long in total. It is designed to radiate UV rays for 10 minutes the dried marine products, and can process 300 kg/hour. Eight UV lamps of 30 cm long and 15 W of power with 254 nm wave length are installed in parallel, 15 cm high above in each belt, and 40 lamps in total. The whole system is covered by 1 mm thick metal plates to block the UV rays except a front side which is covered with 5 mm thick plastic plates coated with UV protection film to survey inside of the system. A sterile ratio is about 99.97% with 10 minutes sterilization using this system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.272-275
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• 2003

Theodolite measurement system is non-contacted 3-dimensional measurement system. The system accuracy is 0.5 mm or better for distance 0 ~ 100 m. And the system is used for the measurement of a product for middle and large scale. This study was performed for finding the measurement error factors of the system. We could know that the main error factors are temperature, illumination and expertness. And we could find the measurement errors are $\pm$ 0.045 mm at temperature conditions is 2$0^{\circ}C$ and $\pm$ 0.012 mm at illumination condition is 300 lux. Also the results had significant differences by combinations of operator's expertness.