• 제목/요약/키워드: 김대식

검색결과 839건 처리시간 0.033초

논 물 관리의 자동화시스템 개발 (Development of the Automated Irrigation Management System for Paddy Fields)

  • 정하우;이남호;김성준;최진용;김대식
    • 한국농공학회지
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    • 제36권3호
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    • pp.67-73
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    • 1994
  • This paper is to validate the proposed models for the real-time forecasting for the Keum river estuary dam such as tidal-level forecasting model, one-dimensional unsteady flood routing model, and Kalman filter models. The tidal-level forecasting model was based on semi-range and phase lag of four tidal constituents. The dynamic wave routing model was based on an implicit finite difference solution of the complete one-dimensional St. Venant equations of unsteady flow. The Kalman filter model was composed of a processing equation and adaptive filtering algorithm. The processng equations are second ordpr autoregressive model and autoregressive moving average model. Simulated results of the models were compared with field data and were reviewed.

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C-rate, 온도, SOC를 고려한 NiMH 배터리 모델링 및 실험 (NiMH battery Modeling and Test considering C-rate, Temperature and SOC)

  • 공세일;김대식;차한주
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2012년도 전력전자학술대회 논문집
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    • pp.413-414
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    • 2012
  • 본 논문에서는 C-rate, 온도, SOC (State-of-Charge, 잔존용량)를 고려하여 NiMH 배터리를 모델링하였고, 시뮬레이션 결과를 배터리 실험 결과와 비교하였다. 제안한 배터리 모델은 1차 테브난 등가회로를 기반으로 구성하였으며 Matlab/Simulink 환경에서 구현하였다. 모델을 구현하기 위한 실험으로는 정전류, 펄스전류 실험을 하여 가변온도와 다양한 C-rate에서 변하는 파라미터를 도출하였고, 도출한 파라미터는 룩업 테이블을 이용하여 배터리 모델에 적용하였다. 제안된 배터리 모델을 짧은 시간동안 불규칙하게 변하는 전류 패턴에 대한 시뮬레이션과 실험 파형을 통하여 배터리 모델의 성능을 검증하였다.

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HID램프와 안정기 사이의 전선 길이에 따른 이그니션 전압 전달특성 분석 (Characteristics of the Ignition Voltage through the Conductor according to its length from the ballast to the lamp)

  • 방선배;김종민;김효진;김대식;한상옥
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.381-383
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    • 2007
  • 본 논문은 HID 램프 관등회로의 전선 길이에 따른 이그니션 전압 전류 특성 분석에 관한 것이다. 현장실태조사를 통하여 HID 램프 관등회로 전선 굵기 선정의 문제점을 제시하고 HID 램프의 이그니션 전압 전류 특성을 분석하였으며, 이론적 고찰과 시뮬레이션, 실험을 통하여 전선의 길이, 종류, 굵기에 따른 이그니션 전압 감쇄 그래프를 제시하였다.

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농업정책결정지원을 위한 국가간 식량 수급 모델링 및 GIS 분석에 관한 연구 (A Study on the Import-Export Modeling and GIS Analysis of the International Provisions for the Agricultural Policy Decision Support)

  • 김대식;이상무
    • 농촌계획
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    • 제4권2호
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    • pp.117-127
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    • 1998
  • In this study, a model was developed to analyze the capacity and the total price of the agricultural products marketing between nations through the estimation of the production and consumption amount of the agricultural products in each nation and the analysis of the price and transport cost to each nation. The method which can contribute to the agricultural policy decision support was devised. The main concept of the method is to compute the potential import-export amount and total cost among the nations. In the application, wheat was selected to evaluate the model. The application results showed that the model could analyzed the unit consumption and storage amount per capital of each nation and the price and transport cost per unit weight from each export nation, provided the policy decision maker with the basic data analyzed by GIS.

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Pentanene을 이용한 Schottky diode의 제작 및 전기적 특성 ((Fabrication and Electrical Characterization of Pentacene - based Schottky diodes))

  • 김대식;이용수;박재훈;최종선;강도열
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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    • pp.53-53
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    • 2000
  • 반도체 산업에서 유기물질의 응용에 많은 관심을 나타내고있으며, 그 응용의 예로는 발광 다이오드(light emitting diode)와 박막트랜지스터(thinfilm transistor)가 주를 이루고 있다. 이러한 유기 물질을 이용하면 소자의 제작 공정의 단순화와 제작 가격을 낮출 수 있는 이점을 기대할 수 있다. 본 연구에서는 유리 기판 위에 pentcence 다이오드를 제작하였다. 유리 기판 위에 silicon dioxide를 PECVD으로 성막하였다. 전극으로는 Ohmic contact를 이루기 위해 금(Au)을 사용하였으며 schottky contact을 이루기 위해서 알루미늄(Al), 인듐(In), 크롬(Cr), 은(Ag), 금(Au)을 각각 사용하였다. 소자의 활성 층으로는 pentcene을 가장 단순한 열 증착법으로 성막하였고, 진공도는 10-8Torr를 유지하였으며 성막 속도는 0.3 $\AA$/sec로 성막하였다. 제작된 소자들은 $\alpha$-step, I-V, C-V, AFM, IR등을 이용하여 측정, 분석하였다.

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중소기업의 업종별 안전공학 기술 (Safety Engineering Technique By Industry on Small & Medium Industry)

  • 김대식
    • 산업융합연구
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    • 제2권2호
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    • pp.31-46
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    • 2004
  • The ratio of industrial injury in Korea is higher 2~4 times than advanced nations like Japan and Singapore, because the industrial injuries in small-medium industry are higher than large size industry. The investment ability is insufficient for working conditions and prevention of the industrial injuries in the small & medium industry. The industrial safety management of machinery manufacturing for transportation, chemical factory, textile product manufacturing, wire & circuit products for computer, plastic goods manufacturing, and metal products manufacturing was investigated. Therefore, the purpose of the paper is to recognize the seriousness of the industrial injuries, understand product, layout, and machinery, and working conditions, etc., and indicate safety engineering techniques for improvement of quality and productivity under this safety working conditions.

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공수표준화에 의한 비정형발주형 작업에 대한 개선 (Job Improvement for Non-Fixed Order by Man-Hour Standardization)

  • 김대식;조명현;손권수
    • 산업융합연구
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    • 제8권1호
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    • pp.19-31
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    • 2010
  • The purpose of this study was to set the standard man-hour of welding work. The case study was conducted at C Tech where makes and installs conveyor. Because most of orders are non-fixed, all jobs are vary in shape and size. To conduct this study, drawings of sample were reviewed and compared with measured man-hours of welding works. As a result, the different ratio of expected require man-hour and measured man-hour was 4%. It is reasonable that the present applied efficiency of aimed man-hour is 85%.

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유해요인 분석도구를 이용한 펄프 및 지류 생산 작업자세의 분석 및 개선 (An Analysis and Improvement for Working Posture of Pulp and Paper Manufacturing using Hazard Factors Analysis Tools)

  • 김대식;이태우
    • 산업융합연구
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    • 제9권1호
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    • pp.1-13
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    • 2011
  • The purpose of this study was to analysis and improve working posture using hazard factor analyzing tools. SI(The Strain Index) came up with the conclusion that RWDR1 and RWDR3 was a dangerous job, but not as dangerous as RWDR2. According to REBA. RWDR3 required some improvements; A mat to prevent fatigue(WIRE/PRESS 2), electric bogie(RWDR1), and waist/wrist protector(RWDR3). Additionally a correct sitting posture m WIRE/PRESS1 and stretching on a regular basis in RWDR2 were recommended.

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항공용 가스터빈 연소기에서의 혼합기 노즐 형상의 단순화가 음향장 해석 결과에 미치는 영향 (Effects of a Simplified Mixture Nozzle Geometry on the Acoustic Field in an Aero Gas Turbine Combustor)

  • 표영민;홍수민;김대식
    • 한국분무공학회지
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    • 제24권2호
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    • pp.58-65
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    • 2019
  • A 3D FEM (Finite Element Method) based Helmholtz solver has been commonly used to characterize fundamental acoustic behavior and investigate dynamic instability features in many combustion systems. In this approach, a geometrical simplification of the target system has been generally made in order to reduce computational time and cost because a real combustor and fuel nozzle have a very complicated flow passage. The feasibility of these simplifications is quantitatively investigated in a small aero gas turbine nozzle in term of acoustic characteristics. It is found that the simplification in a nozzle geometry during the 3D FEM analysis process has no great influence on the acoustic modeling results, while the calculation complexity can be improved for a similar modeling accuracy.

선발브랜드와 후발브랜드간의 환경 불확실성 지각에 관한 연구 (A study on the cognition of Environmental Uncertainty between Pioneer brand and Follower brand)

  • 김세환;김대식
    • 산업융합연구
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    • 제4권2호
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    • pp.39-55
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    • 2006
  • Pioneer brand and follower brand show differences in their perception of the environmental uncertainty. Market pioneer brand companies think that the environment is relatively simple and doesn't change much, whereas follower bland companies think that the environment is complicated and changes a lot. For market pioneer brand companies, among dynamism on the environment lever, there was less potential for the environment and parts, and government restrictions compared to follower brand companies. Also the complexity of the environment level complicated compared to the follower brand companies in areas such as competition for consumers with rival companies, materials, resources of equipment and parts, government restrictions, and the amount of change of the market's preference of the product.

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