• Title/Summary/Keyword: 김철환

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A Study on IETM Conversion procedure and IETMDB Construction (IETM의 변환절차와 IETMDB구축에 대한 연구)

  • 김철환;이정환
    • The Journal of Society for e-Business Studies
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    • v.1 no.2
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    • pp.1-25
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    • 1996
  • This study aims to provide conversion process to acquire IETM and fundamental IETMDB construction necessary for IETM. As the weapon system and other equipments are highly advanced and electronically sophisticated, the amount of information necessary to operate and maintain the systems is being dramatically increased. Thus, it is theoretically and practically impossible to maintain the huge amount of information in the paper-based manual. Furthermore, the vast amount of paper based-technical information makes it difficult to share them in real time. This paper discuss how to solve these prolems by using highly advanced information technology such as network, database, data communication, etc First, we propose an effective conversion process for the decision of IETM classes from Class 1 to Class 5. Second, we also propose a construction of IETMDB and IETM system by using CALS standard and Content Data Model (CDM).

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A Survey m Demand and Activation of Mobile Internet Business (무선인터넷 비즈니스 수요조사 및 활성화 방안)

  • 김철환;오광운
    • The Journal of Society for e-Business Studies
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    • v.7 no.3
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    • pp.1-19
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    • 2002
  • This research investigates several essential topics of m-business by conducting a questionnaire to the professional experts. The topics include the market structure and business, the demand for available m-business service and its development, the market size and market growth factors, the service fee, the core technologies and technology development prediction. This paper contributes to the development of m-business in that it provides criteria and policies for more active and efficient treatment of m-business market under IMT2000 environment and also offers guides and plans of m-business activation for both government and enterprise.

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A Study on the Voltage Sag During the EVs Charging Considering Domestic Data (국내 데이터를 고려한 전기 자동차 충전 시 순시전압강하에 관한 연구)

  • Go, Hyo-Sang;Kim, Jun-Hyeok;Kim, Eung-Sang;Kim, Chul-Hwan
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.1
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    • pp.37-46
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    • 2015
  • In order to charge EVs, they have to be connected to distribution system. Therefore, if unprecedented numbers of EVs are connected to power systems, it could result in deterioration of power quality, overload, and other system problems. In this paper, the effects of voltage sag on the distribution system due to the connection of EVs is evaluated by considering related field data of Republic of Korea such as the number of gasoline-fueled vehicles, seasonal load of power system and the monthly and daily real-time traffic volume. The distribution system and EVs are modeled using the Electro Magnetic Transients Program (EMTP).

Development of Interactive Software for Integrated Analysis in Power System (전력계통의 종합적인 해석을 위한 대화형 소프트웨어의 개발)

  • Shin, Myong-Chul;Hong, Jin-Pyo;Kim, Chul-Hwan
    • Proceedings of the KIEE Conference
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    • 1990.11a
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    • pp.252-255
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    • 1990
  • Analyzing and simulating of today's complex electrical networks require the use of computer-aided engineering tools. In recent years, the rapid advances in micro-computer hardware technology have increased the availability of power application software on the personal computer, once the domain of mainframes and minicomputers, enabling efficient and cost-effective power system analysis. An interactive simulation and analysis software for a power system is developed and presented in this paper. The software is written in PASCAL and is designed for PC use. This paper presents an integrated software package to run PC-DOS for the analysis of electric power networks. The software is menu driven and controlled by prompts. These programs are intended to help users understand the process of power system analysis and design.

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High Impedance Fault Detection using Wavelet Transform (Wavelet 변환을 이용한 고저항 지락고장 검출)

  • Kim, Hyun;Kim, Chul-Hwan
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.12
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    • pp.1492-1497
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    • 1999
  • High impedance fault(HIF) is defined as fault the general overcurrent relay can not detect or interrupt. Especially when HIF occur in residential areas, energized high voltage conductor results in fire hazard, equipment damage or personal threat. This paper proposes the model of the high impedance fault in transmission line using the ZnO arrester and resistance to be implemented within EMTP. The performance of the proposed model is tested on a typical 154[kV] korean transmission line system under various fault conditions. Wavelet transform is efficient and useful for the detection of high impedance fault in power system, because it uses variable windows according to frequency. In this paper, HIF detection method using wavelet transform can distinguish HIF form similar fault like arcfurance load, capacitor bank switching and line switching.

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Analysis of Pressure Drop for Combining Junctions in Gas-Liquid Two-Phase Flows (기액 2상 유동에서 합지관에서의 압력강하에 대한 해석)

  • 김철환;하삼철;김은필;김경천
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.9
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    • pp.870-878
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    • 2000
  • An experimental study and a modeling are peformed to investigate the pressure drop of combining junctions in two-phase flows. Experiments on tripod geometry used in a condenser or an evaporator, are conducted with inlet mass fluxes from 200 to$ 400 kg/m^2$s, and pipe diameters of 7 m and 9.52 m. The working fluid is R22. The result shows that the pressure drop increases as the quality does, but the effect of the increase of the pressure decreases when the diameter of a pipe increases. When the mass flux increases, the pressure drop linearly does. Furthermore, when the pipe diameter decreases, the pressure drop has a quadratic increase.

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A study on the Flexural Behavior of Structural Deck Plate using High-Strength Lightweight Concrete (고강도경량콘크리트를 사용한 구조용 Deck Plate의 휨거동에 관한 연구)

  • 김철환;최명신;안종문;김범조;소병규;신성우
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04b
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    • pp.505-512
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    • 1998
  • The object of this study is investigated to flexural behavior of structural deck plate composite slabs using high-strength lightweight concrete. Test variables are concrete compressive strength (normal weight concrete 210kg/$\textrm{cm}^2$, lightweight concrete 270, 350kg/$\textrm{cm}^2$), topping concrete thickness (70, 75mm when span is 3.4m), deck plate depth (50, 75mm when topping concrete thickness is 70mm and span is 3.4m) and span(3.0, 3.4m). Test results are compared with current ACI Building Code(318-95). The test results are follows ; (1) a value of Ptest/Pcal is 1.27~1.39, (2) a mean value of $\delta$test/ $\delta$ACI is, 0.60 when deflection is reatched to maximam permissible computed deflection (L/360), and (3) ductility index are 3.61~6.85.

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Giant Dermoid Cyst in Mouth Floor (구강저에 발생한 거대한 유피낭종)

  • Kim, Chul-Hwan;Park, Sung-Min;Lee, Chul-Won
    • The Journal of the Korean dental association
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    • v.49 no.8
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    • pp.472-477
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    • 2011
  • Dermoid cyst is a benign neoplasm, so called by teratoma that is derived from both ectoderm and mesoderm during embryonic period. The majority of dermoid cysts are found in the ovaries and approximately only 7% of dermoid cysts are found in the head and neck. The growth of dermoid cysts in the floor of the mouth is considered a rare condition. We report one case of huge dermoid cyst in the floor of mouth suffered with double chin appearance and difficulty in pronunciation and respiration. The cyst was excised successfully only intra-oral incision. Clinical progress was uneventful and postoperative recovery excellent without recurrence.

A Study on Feasibility Analysis and Alternatives for Infrared Detector Development (적외선 검출기 개발가능성 및 대안 분석 연구)

  • Kim, Gyeong-Su;Min, Seong-Gi;Kim, Cheol-Hwan
    • 시스템엔지니어링워크숍
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    • s.4
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    • pp.123-134
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    • 2004
  • This paper deals with the feasibility analysis and alternatives for infrared detector development. The purpose of this paper analyze development requirement and feasibility study in both technology and cost. We get raw input data for system engineering process from development and technical expert, and then analyze cost and technology for development feasibility, and alternative study. Infrared Detector is core component of Thermal Imaging System and developed by ADD from 2006 to 2008 year. Technical level is analyzed by TRL(Technical Readiness Level) and AOA(Analysis of Alternative) is done by development and production cost estimate. We use SEER-H tool for cost estimate, that is parametric cost estimate tool based on Knowledge Base. Also this paper presents risk analysis for project management because it is necessary to risk driver management during the infrared detector development. The result of IR Detector feasibility and alternative study will be used in technical and cost analysis. This study can help those who are related to the cost analysis and development feasibility of other weapons

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NUMERICAL STUDY ON FLOW CHARACTERISTIC IN THE HEAT RECOVERY STEAM GENERATOR (배열회수장치의 유동특성에 관한 수치적 연구)

  • Choi, H.K.;Yoo, G.J.;Shin, B.J.;Kim, C.H.
    • Journal of computational fluids engineering
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    • v.15 no.1
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    • pp.17-23
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    • 2010
  • Performance improvements of the heat recovery steam generator(HRSG) can be achieved by improving the flow distribution of exhaust gases for a various type of different equipments. A number of design parameters are systematically investigated and their effects on an index of velocity deviation established. The parameters include the three shape of the transition duct and the wide range of the guide vane angles. The numerical results clearly reveal feature of the flow pattern in the transition duct, velocity deviation and pressure drop at tube bank part.