• 응용통계연구
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• 제13권2호
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• pp.489-503
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• 2000

다양한 형태의 데이터로부터 의사 결정에 유용한 정보 및 지식을 발견하려는 일련의 데이터분석 및 모형 선정과정을 데이터 마이닝(Data Mining)이라고 할 수 있다. 데이터 마이닝의 적용 예로는 신규고객에 대한 신용평가, 고객이탈방지 등과 같은 분야에서 발생하는 스코링 문제를 들 수 있는데 신용평가에서는 신용이 나쁠 가능성을 스코어로 나타내고 스코어가 높은 고객을 대상으로 특별관리를 할 수 있을 것이며 고객이탈방지에서는 이탈가능성을 스코어로 나타내고 스코어가 높은 고객을 대상으로 이탈 방지 캠페인을 벌일 수 있을 것이다. 본 논문에서는 스코링 문제를 사후확률에 대한 모형화 문제로 파악하였다. 폴리클라스를 스코링 문제에 적용하는 방법을 소개한 후 이를 독일 신용 데이터, 국내 모 PC통신회사 데이터 및 국내 모 이동통신 데이터에 적용하였다. 스코링의 성능은 이득률을 이용하여 평가하고자 하는데 나무 모형에 비하여 폴리클라스 방법이 우수함을 확인하였다.

• 대한기계학회논문집
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• 제14권2호
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• pp.358-366
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• 1990

As a basic study to clarify the scoring resistance in lubricated sliding contact, the temperature rise on frictional surface was analyzed by theoretical method and the effects of various factors on the temperature rise were examined. On the basic of the results obtained theoretically, the practical equations to calculate the maximum average temperature of the contact surface were proposed which are applicable to sliding contact. Then, the effects of sliding velocity and oil temperature on the seizure behavior, and the relation between seizure and temperature rise were investigated. The following conclusions are deduced : The maximum average temperature rise and the other bulk temperature. The former is affected by the size of heat supply region and the sliding velocity, the latter is affected by heat transfer coefficient. Without regard to the operating condition such as sliding velocity, oil temperature and operating time at each load-step, the maximum average temperature just before seizure is nearly constant except in the region of lower velocity. Consequently, the maximum average temperature of the contact surface in boundary lubrication is a useful criterion to predict the scoring of sliding contact.

• 동력기계공학회지
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• 제13권6호
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• pp.102-109
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• 2009

A retarder, as a supplementary brake system that is not friction-based, is frequently used in heavy-duty vehicles generally to slow the vehicles down on inclines. The electric retarder mainly used in a heavy-duty bus is generally placed between the transmission and the axle. The rotor inside the retarder system is attached to the axle. The operation of the retarder within a driven vehicle generates reverse torque due to coast driving force on hypoid gears in the differential gear system. By the reverse torque, scoring or scuffing on the hypoid gear teeth may directly occur. The scoring may be generated due to excessive contact stresses on the tooth surface. In this study, tooth contact stresses and contact patterns were analysed in order to investigate on the tooth scoring phenomenon using a finite element analysis program T900 in which the Hertzian contact stress formula was taken. Backlash, wear and surface finish were considered in the finite element simulation on the scoring.

• 대한기계학회논문집
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• 제14권3호
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• pp.594-602
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• 1990

본 연구에서는 동력전달용 인벌류우트 원통치차(스퍼어 및 헬리컬 기어)의 강 도 및 각종 영향인자를 충분히 고려하면서 크기를 최소로 하는 치차장치의 설계법을 개발하고, 이 설계법을 기본으로 하여 퍼스널 컴퓨터 상에서 누구나 손쉽게 설계에 이 용할 수 있는 설계 시스템을 개발하여 그 평가를 수행한다.

• 한국정밀공학회지
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• 제12권7호
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• pp.66-73
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• 1995

Rating systems of bevel gears(straight, spiral, and zerol bevel gears) which are commonly used as power transmission devices for non-papallel axes are developed on the personal computer, which analyze and/or evaluate the gear design and the service performance at the point of view of strength and durability. The typical considerations of the ratings are the bending strength, the surface durability, and the scoring resistance. The ratings are carried out using the reliable standards of AGMA & Gleason Works. Therefore, the system is built so that the variables or factors considered differently in those standards and the strength, dura- bility, and scoring partially in Gleason are appraised seperately by each method, and a series of the estimation processes is integrated into the system so as to compare each result. The developed rating systems can be used in the initial stage of gear design process, and also a better design can be performed by the evaluation of the initial design at the view point of gear strength and durability. Additionally, it is useful for the trouble-shooting of bevel gear system and to the purpose of introducing the methods for maintaining design strength in service, with appraising the gear strength after design or with appraising the influencing factor as a whole. Therefore, this rating systems can help the aim of design automation of bevel gears.