• Journal of the Korean Data and Information Science Society
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• v.7 no.1
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• pp.59-68
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• 1996

In this paper, we consider how to estimate New Better Than Used (NBU) survival curves from randomly right censored data. We propose several possible NBU estimators and study their properties. Numerical studies indicate that the proposed estimators are appropriate in practical use. Some useful examples are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.153-154
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• 2011

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1093-1094
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• 2011

전 산업분야에 사용되는 전자기기 및 장비에 탑재되는 케이블의 경우 업종에 따라 기기에 맞춰 신뢰성을 검토하고 인증을 획득하여 해당 기기에 탑재되고 있다. 그러나 현재 선박이라는 특수 환경에서의 특성에 맞춰 검토되거나 규정되고 있는 케이블 신뢰성에 대한 연구는 다양한 접근방법에서 검토되지 않고 있다. 바다 위라는 제한된 환경에서 선박과 생사를 같이 하는 케이블의 신뢰성은 필이 검토되어야 하는 부분이다. 본 논문은 선박에 탑재되기 위한 케이블의 신뢰성에 대한 기준과 자료에 대해 언급하고자 한다.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.466-466
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• 2007

• Journal of Korean Institute of Industrial Engineers
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• v.3 no.2
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• pp.83-91
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• 1977

This paper investigates the reliability characteristics of a system consisting of a unit operating on-line and backed by n spares among which m units are kept "warm" as standbys ready to go on-line. The on-line unit has an arbitrary lifetime distribution, while the warm standbys have exponential failure time distributions. The Failed units are repaired and brought back to service. The cold spares do not fail while in storage. Solution of this extremely complicated queuing problem using a "renewal counting" approach is presented and extended to the situation where the warming-up takes non-negligible time. Finally, an approach to the economic system management is discussed, considering the long-run availability, cost of keeping spares and repair facility, and the associated cost of restarting the system, after a system failure. The model presented in this paper will have many applications including the determination of the spares inventory and the number of field spares to be "carried".

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.107-116
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• 1994

In this paper, The electrical properties of MOS capacitors and transistoras with gate of in-situ doped amorphous Si and poly Si doped by POCI$_3$. Under constant current F-N stress, MOS capacitors with in-situ doped amorphous Si gate have shown the best resistance to degradation in reliabilty properties such as increase of leakage current, shift of gate voltage (V$_{g}$). shift of flat band voltage (V$_{fb}$) and charge to breakdown(Q$_{bd}$). Also, MOSFETs with in-situ doped amorphous Si gate have shown to have less degradation in transistor properties such as threshold voltage, transconductance and drain current. These improvements observed in MOS devices with in-situ doped amorphous Si gate is attributed to less local thinning spots at the gate/SiO$_2$ interface, caused by the large grain size and the smoothness of the surface at the gate/SiO$_2$ interface.

• Fashion & Textile Research Journal
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• v.11 no.1
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• pp.93-102
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• 2009

The purpose of this study was to analyze the factor of fashion behavior and to identify fashion behavior differences according to demorgraphic/physical characteristics and parents' background of male college student in Dalian, China. The data were collected via a self-administered questionnaire from 250 male college students living in Dalian, China in June 2007. Data analysis method were used to Crombach's a, reliabilty, factor analysis, frequency analysis, ANOVA, and Sheffe's test for the post hoctest. The results of this study were as follows: Fashion behavior factors were analyzed into 6 factors such as fashion satisfaction oriented, high price oriented, fashion leader oriented, practical fashion oriented, others defendence oriented. There were significant difference in demographic variables such as age, major and physical variables such as height, weight, clothing size and parents' background such as education, job, and income.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.33 no.10
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• pp.387-395
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• 1984

This paper proposes an improved unit commitment algorithm for the purpose of rational operation of electric power systems. Security function is introduced to consider generation system reliability as well as economical properties in the algotithm . As a stte model for assessment of state probabilities, the 3-state model in which the probability of the units for commitment can be considered is proposed and applied, so that the algorithm becomes more practical and reasonable one. A decision bounding scheme which can be applied to all kinds of system is described and the numerical results obtained for KEPCO and model systems are also presented to assure the availability of the proposed technique.

• Research in Community and Public Health Nursing
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• v.21 no.2
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• pp.156-168
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• 2010

Purpose: The purpose of this study was to construct a questionnaire to assess male workers' sobriety behavior based on Ajzen's Theory of Planned Behavior (TPB). Methods: A primary questionnaire with 56 questions was constructed based on literature review and structured interview with male workers. The Content Validity Index (CVI) was evaluated by a group of experts, construct validity was tested by principle component analysis, and reliability was evaluated by Cronbach's ${\alpha}$ and the test-retest reliability test. Results: Fifty two questions showed higher than .8 of CVI. Four factors explained 78.71% of the total variance among items for sobriety intention and direct measure, and six factors explained 67.99% of the total variance among indirect measure items and those factors coincided with the variables of TPB in factor analysis. Cronbach's ${\alpha}$ of this questionnaire was .873 and the result of test-retest reliabilty test was relatively reliable. A total of 41 items with 7-point scale were constructed in the final version. Conclusion: This questionnaire was valid and reliable to measure sobriety behavior based on TPB in male workers. It can be useful to evaluate the result of a sobriety program for male workers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.9-15
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• 1991

This study is directed for the development of rational rating models for realistic safety assessment and the computer rating system for highway bridges. For this purpose, the conventional rating system is considerably improved in appropriate way, and a rational rating system based on the reliabilty method is proposed to estimate safety of deteriorated bridges by using only the visual inspection data or the statistical data available. In addition. the rating system which can assess the realistic allowable passing tonnage of military vehicles in case of the military operations is also presented. From this study, it is known that the presented rating system and the computer program BRS(Bridge Rating System) provide an effective tool which can handle the degree of deterioration and various uncertainities of the bridge systematically. so it can be used widely for assessment of safety and load carrying capacity of existing deteriorated or damaged bridges.