• 한국생산제조학회지
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• 제24권6호
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• pp.653-659
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• 2015

The aim of this study is to develop a technique for the accelerated life test of the capacitor in a propulsion control device of a traction inverter used for a high-speed train. Using this technique, the accelerated life test can possibly estimate the life cycle of a capacitor under various temperature conditions and irregularly applied voltage. The accelerated life test is conducted for the capacitor of the traction inverter. The common proceedings of this test are selection of failure mechanism, determination of accelerated stress, range determination of the accelerated stress, determination of the test condition, and distribution and determination of the sample. From this result, the continuous applied voltage was not considered for the acceleration factors anymore. Therefore, the final result having an acceleration factor of 9.4 (= 13,626/1,445) was observed. Furthermore, the life-shortening acceleration effect for the irregular applied voltage condition can be applied to various situations.

• 조명전기설비학회논문지
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• 제28권7호
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• pp.34-40
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• 2014

In this paper, we want to know the optimal replacement cycle(time) for this study was performed. The optimal preventive replacement age can be fond by finding the value of time that minimizes the cost function(model of Barlow and Jardine). In addition, The reliability of the relay according to the service environment were studied. The use of the exchange relay period is longer, and maintenance cost rate(per hour) may increase, and also the reliability may cause a decline. In addition, considering the preventive maintenance and purchase order, a representative relay(RAX-L440-A type) life was calculated.

• 한국공작기계학회논문집
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• 제10권3호
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• pp.55-60
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• 2001

A technique on the detection of tool wear based on the ultrasonic pulse-echo method in turning process is presented. The change in amount of the reflected energy from nose and flank of the tool can be related to the level of tool wear and mechanical integrity of the tool, that is, there exists an excellent correlation between the ultrasonic measurement and tool wear. As a results, the method is very useful for the prediction of cutting tool life and the determination of tool exchange period.

• 한국조리학회지
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• 제10권1호
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• pp.32-45
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• 2004

This study is about choice attribution of customers make in food and beverage events. The researcher provided practical plans to uplift food-related enterprises and activate management through surveys and positive analyses, targeting customers who use food services. First of all, all event plans must include customer demands, social changes, special qualities of the business, and market research. Second, low demand season must be customers will be induced to the events. Third, prediction for market variable and solutions must be thoroughly examined and plans should look into the future to maintain a long period of time. Fourth, sufficient communication between planners and employees should be made before the event starts, so that food and beverage businesses can gain trust and quality of event services.Fifth, immaterial service and visible goods/menus in business of food and beverage events must be closely matched. Sixth, menus introducing a variety of merchandise, quality of nutrition and health of the business should be developed. Also, events from countries(regions) should be hold to create a market of cultural exchange. Seventh, for hereafter event plans, feedbacks are needed concerning customers needs and demands through customer care, after the food and beverage events. Eight, faculty management for convenience, kindness, safety, and life preserver accommodations in parking areas must be made, as automobiles are necessaries for people in Mycar era. The ninth, off-line and on-line care through on-line business construction and production of homepage must be done, due to the fact that even the well-made events are bound to fail if they are not delivered to the customers.