• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1667-1672
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• 2007

In order to assess the reliability of the exhaust bellows for automobiles, accelerated life test model and procedure are developed. By using this method, failure mechanism and life distribution are analyzed. The main results are as follows; i) the main failure mechanism is crack or breakage of inner flexible tube by shaken displacement at shear direction. ii) temperature is a second factor to affect a failure. iii) the life distribution of exhaust bellows is fitted well to Weibull life distribution and the shape parameter is 13.3 on condition of shaken displacement and $600^{\circ}C$

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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• pp.32-41
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• 2003

For the countermeasure of expected higher thermal load in miller cycle engine, coolant flows in the cylinder head of base engine with several coolant flow methods and drilled hole passages were measured by using PIV technique. And the cooling effect was evaluated by measurements of wall temperatures according to each coolant flow method. It was found that the series flow system was most suitable among the discussed 3 types of coolant flow methods since it had the best cooling effect in cylinder head by the fastest coolant flow velocity It was also found that for drilled water passage to decrease the large thermal load in exhaust valve bridge, nozzle type is more effective compared with round type of water passage, and its size has to be determined according to the coolant flow pattern and velocity in each cylinder.

• The Research Journal of the Costume Culture
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• v.12 no.3
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• pp.468-484
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• 2004

The purposes of this study were (1) to segment female college students' apparel shoppers into unique apparel buying decision-making style groups; and (2) to profile for each segment in terms of personal characteristics (material values, change seeking tendency and prestige sensitivity) and fashion information sources. Data were collected through questionnaires from convenient sample of 290 female college students. As a result of cluster analysis and univariate analysis of variance, distinctive consumer decision-making style groups of consumers were identified; Value-maximizing Recreational Shoppers, Brand-Maximizing Emotional Shoppers, and Apathetic Shoppers. These three groups were compared as to the effect of personal characteristics variables and fashion information sources through univariate analysis of variance and chi-square statistics. The result showed that personal characteristics (material values, change seeking tendency and prestige sensitivity) and fashion-information sources do influence the consumer decision-making styles and that these three groups were unique in their decision-making characteristics showing that consumer decision-making styles can be a good segmentation base for apparel market.

• Journal of Families and Better Life
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• v.12 no.1
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• pp.132-144
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• 1994

본 연구는 '소비자중심'의 주거문화를 모색하기 위해 한국사회 신세대소비자의 주거 가치와 관련요인에 대해 수도권의 20~35세 남녀를 대상으로 자기기입식 질문지를 이용하여 실증연구하였고 주요 연구결과는 다음과 같다. 첫째, 14개 주거가치에 대해 전반적으로 중요 하다는 응답이 대부분이었다. 둘째, 주거가치의 요인분석결과 4개 특성이 추출되었고 두 맥 락으로 접근할 수 있었다 하나는 후기 산업사회로의 발전과 함께 중요하게 인식되는 주거가 치특성으로 외부환경의 편리성과 인간성 회복 인접환경의 안전과 프라이버시 내부환경의 편 리성과 아름다움을 중시하는 주거가치가 이에 속한다. 이주거가치들은 신세대소비자에게 매 우 강하게 형성되어 있었으며 공통적으로 신세대가치관이 강할수록 더 강한 것으로 나타났 다. 다음은 전통적으로 중요시된 주거가치로서 위신과 경제성 주거가치이다 이는 비교적 낮 은 수준으로 나타났으며 신세대가치관이 약할수록 더 강하게 나타났다.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.55-60
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• 2011

Recently, the application of electronics in vehicle is increasing, in order to assess the reliability of the electronics, highly accelerated life test is used, highly accelerated life test can assess the reliability of the electronics in the short time. In this study, optimized HALT technique can be applied to the electronics is proposed. The main results are as follows; i) HALT is proceed to the 8-step process. ii) The test mode of HALT is composed of the cold step stress, hot step stress, vibration step stress and combined environments stress. iii) The time dwell is set to at least 20 minutes.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.41-48
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• 2011

In order to assess the reliability of the Tire Pressure Sensor for automobiles, accelerated life test model and procedure are developed. By using this method, failure mechanism and life distribution are analyzed. The main results are as follows; i) the main failure mechanism is degradation failure that is, PCB destruction and battery Discharge by high temperature. ii) the life distribution of the Tire Pressure Sensor fitted well to Weibull life distribution and the accelerated life model of that is fitted well to Arrhenius model. iii) at the result of the life distribution, accelerated life test method is developed

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1361-1366
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• 2008

Failure mechanism of the poor contact is analyzed on the basis of used connectors and this poor contact of connectors is reappeared by the new forced fretting wear method. As the result of failure analysis and reappearance, fretting wear and corrosion of the contact interface causes the contact resistance degradation and the poor contact of connectors. The amount of degradation depends on the fretting stroke. Changes in contact resistance of static contacts are likely to be small and gradual, while motions of contact interface may result in larger and discontinuous changes in resistance and voltage. This voltage drop by fretting motions is large enough to cause the distortion of sensor signal and mis-working of electric components.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.6
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• pp.1-10
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• 2002

As the preliminary stage for the countermeasure of thermal loading in miller cycle engine, coolant flows in the cylinder head of base engine including exhaust valve bridge were visualized and analyzed by using PIV technique. It was found that low coolant velocity regions were around exhaust valve bridge, around which stagnation of the coolant flow was observed due to the complex geometry configuration of water jacket. And velocity variation between each cylinder was remarkable. For the countermeasure of these, it is necessary to enhance coolant flow around exhaust valve bridge and to improve the deviation of coolant flow between each cylinder.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.3
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• pp.1-11
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• 2000

Instantaneous temperature probes were manufactured by pressing method. By using these probes, the instantaneous surface temperature and unsteady heat flux in the cylinder liner of DOHC engine were measured. The main results are as follows; ⅰ) the instantaneous surface temperature of cylinder liner are affected by the contact of piston ring as well as burning gas. ⅱ) the wall temperature of the siamese portion is much higher than other parts. ⅲ) it was shown that the rising trend of heat flux by burning gas are nearly limited to the 1/2-stroke distance from the top of cylinder liner.

• Journal of Hydrogen and New Energy
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• v.12 no.2
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• pp.147-155
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• 2001

To measure of thermal loading in the combustion chamber of hydrogen engine with dual injection, instantaneous wall-surface temperature and unsteady heat flux of the cylinder head are measured and analyzed. The maximum wall surface temperature is shown in direct injection region which has large heat supplied. Partial and spatial temperatures have slight deviation in transient region of injection, though injection method change suddenly. All of thermal characteristics such as instantaneous temperature, temperature swing and heat flux of hydrogen engine with dual injection are remarkably higher than those of gasoline engine. It means necessity of additional countermeasure of thermal loading.