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데이터 마이닝을 이용한 패트리어트 수리부속의 간헐적 수요 예측에 관한 연구
박천규(Cheonkyu Park),마정목(Jungmok Ma) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.3
군에서는 수요예측에 대한 중요성을 인식하여 수리부속에 대해 예측 정확도 향상을 위한 많은 연구가 이루어지고 있다. 수리부속 수요예측은 예산 운영과 장비 가동률 측면에서 매우 중요한 요소가 되고 있다. 그러나 현재 군에서 적용중인 시계열 모형으로는 수요량의 변동과 발생주기가 일정하지 않은 간헐적 수요에 대해서는 예측에 한계가 있는 실정이다. 따라서, 본 연구는 공군 패트리어트 수리부속의 간헐적 수요에 대한 예측 정확도를 제고하는 방법을 제시하고자 하였다. 이를 위해서 2013년부터 2019년까지의 701개의 수리부속 소모개수를 토대로 수요 유형을 구분하여 수리부속의 간헐적 수요 자료를 수집하였다. 또한, 장비 고장에 영향을 줄 수 있는 외부 요인으로는 기온, 장비운영시간을 식별하여 입력변수로 선정하였다. 그 후, 소모개수와 외부 요인을 통해 군에서 적용하는 시계열 모형과 제안하는 데이터 마이닝모형으로 예측을 실시하여 모형별 예측 정확도를 판단했다. 예측 결과로 기존의 시계열 모형과 비교하여 데이터 마이닝모형의 예측 정확도가 높았으며, 그 중 다층 퍼셉트론 모형이 가장 우수한 성능을 보였다. By recognizing the importance of demand forecasting, the military is conducting many studies to improve the prediction accuracy for repair parts. Demand forecasting for repair parts is becoming a very important factor in budgeting and equipment availability. On the other hand, the demand for intermittent repair parts that have not constant sizes and intervals with the time series model currently used in the military is difficult to predict. This paper proposes a method to improve the prediction accuracy for intermittent repair parts of the Patriot. The authors collected intermittent repair parts data by classifying the demand types of 701 repair parts from 2013 to 2019. The temperature and operating time identified as external factors that can affect the failure were selected as input variables. The prediction accuracy was measured using both time series models and data mining models. As a result, the prediction accuracy of the data mining models was higher than that of the time series models, and the multilayer perceptron model showed the best performance.
디메틸에테르에 첨가된 윤활성향상제의 윤활특성에 관한 연구
박천규(Cheonkyu Park),장은정(Eunjung Jang),정충섭(Choongsub Jung),이봉희(Bonghee Lee),나병기(Byungki Na) 한국트라이볼로지학회 2013 한국윤활학회지(윤활학회지) Vol.29 No.2
Dimethyl ether (DME) has a high cetane number that is suitable for diesel fuel. DME does not contain sulfur or nitrogen , and is an oxygenated fuel so it produces no particulate matter when combusted and is environmentally friendly. DME fuel for diesel engines show excellent material properties such as a lower volumetric heating value, lower boiling point, lower lubricity, and stronger solvent effect than light oil. This study experimentally examined a lubricity improver (LI) for dimethyl ether. A diesel LI based on biodiesel and fatty acid methyl ester was tested among DME LI candidates. The long-term storage stability and physical properties of the optimum LI for DME were determined.
박천규(Cheonkyu Park),연주민(Jumin Youn),이민호(Minho Lee),임의순(Euisoon Yim),정충섭(Choongsub Jung),나병기(Byungki Na) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
DME(Dimethyl ether) is focused as an alternative fuels because it could be made from various sources such as biomass, natural gas, coal and coal bed methane. DME could be an ideal substitute for diesel or liquefied petroleum gas (LPG) in the next several decades. DME is a colorless gas at an ambient condition and easily liquefied under pressure. Since the physical and chemical characteristics of DME are very similar to those of LPG, it is an easy substitute of LPG. While DME’s physical properties are similar to LPG, DME has a lower calorific value than LPG, and therefore cannot be used in Autogas engine equipment that are rated for LPG. This paper will explain LPG vehicle performance characteristics and exhaust emissions using DME-LPG blends fuel and, discuss about vehicle characteristics according to vehicle mileage.
DME-LPG 혼합연료의 액상분사식 LPG엔진의 성능 및 배출가스 특성 연구
박천규(Cheonkyu Park),연주민(Jumin Youn),이민호(Minho Lee),임의순(Euisoon Yim),정충섭(Choongsub Jung),나병기(Byungki Na),오승묵(Seungmook Oh) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
DME (Dimethyl ether) is a multi-source, multi-purpose, clean and environmentally friendly form of energy. It also has potential to complement LPG since their physical properties are similar. Therefore, DME is able to contribute to LPG supply and energy diversification. It can be used as a diversion to LPG import prices and provide one solution to the issue of LPG supply. DME fuel has been investigated for diesel engine, as cetane number of DME is almost same as diesel. While DME’s physical properties are similar to LPG, DME has a lower calorific value than LPG, and therefore cannot be used in Autogas engine equipment that are rated for LPG. This paper will explain LPi engine performance characteristics and exhaust emissions using DME-LPG blends fuel and, discuss about optimum blending ratio of DME-LPG blends fuel.
국내 수송용 연료로서 LPG 대체 DME 연료의 적용 연구
연주민(Jumin Youn),박천규(Cheonkyu Park),이민호(Minho Lee),임의순(Euisoon Yim),정충섭(Choongsub Jung) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
Dimethyl ether (DME) can used to as a clean diesel alternative fuel due to the high cetane number and low emission, it can also be applied to automotive fuel as a blended liquefied petroleum gas (LPG) because physical properties are similar to those of LPG. In this study, feasibility test of LPG vehicle with blended DME-LPG fuel are investigated. The LPLi, LPGi and Mixer type of vehicles according to LPG fuel-injection system are selected. The performance characteristics of LPG vehicle have been examined with LPG and blended DME-LPG fuel in order to compare the exhaust emissions (CO, THC, NOx) and fuel economy. The emissions and fuel economy of blended DME-LPG fuel were not different to compared with LPG according to increasing driving distance.
Development of additives for DME as a renewable energy
장은정(Jang, Eunjung),박천규(Park, Cheonkyu),임의순(Yim, Eui-Soon),정충섭(Jung, Choong-Sub),이봉희(Lee, Bonghee) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.05
DME is generally expected to be used as a promising clean alternative fuel to diesel fuel. DME is not natural product but a synthetic product that is produced either through the dehydration of methanol or a direct synthetic from syngas. As DME has no carbon-carbon bond in its molecular structure and is an oxygenate fuel, it's combustion essentially generates no soot. DME has such cetane number of 55~60 that it can be used as a diesel engine fuel. However, DME has low lubricity but a proven method to solve the poor lubricity is by adding lubricity improver. Therefore, the aim of this study is to develop lubricity improver of DME as a transport fuel in Korea. In this study, we investigated a possibility of fatty acid ester compounds as a candidate to improve DME lubricity as compared with current lubricity improver of diesel. We also evaluated quality characteristics, storage stability of DME with lubricity additives.