• 한국산업융합학회 논문집
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• 제13권4호
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• pp.211-217
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• 2010

As the vehicle components are various, we confront unexpected problems in the development and application of them. also warranty expenses occur in the result of unconfirmed warranty.in this paper, to solve the problems of disconnection of damper Strut cable, we applied the optimum conditions through taguchi method for improvement of durability. and we made standard of reliability by weibull analysis of the field data. we acquired reliability standard by correlation with lab data and confirmed improved components satisfying the target of reliability. The analysis of reliability by field data is very useful and we need to apply this method to other components, the correlation between field data and Lab Test has influence on satisfying the target of reliability.this method would be utilized for current mass production components and upcoming developed components. the reliability of durability should be continuously used in the basis of primary technique in cope with competitive automotive companies.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.19-27
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• 2014

Software reliability in the software development process is an important issue. Software process improvement helps in finishing with reliable software product. Infinite failure NHPP software reliability models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, proposes the reliability model with log type mean value function (Musa-Okumoto and log power model), which made out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on mean square error (MSE) and coefficient of determination($R^2$), for the sake of efficient model, was employed. Analysis of failure using real data set for the sake of proposing log type mean value function was employed. This analysis of failure data compared with log type mean value function. In order to insurance for the reliability of data, Laplace trend test was employed. In this study, the log type model is also efficient in terms of reliability because it (the coefficient of determination is 70% or more) in the field of the conventional model can be used as an alternative could be confirmed. From this paper, software developers have to consider the growth model by prior knowledge of the software to identify failure modes which can be able to help.

• 한국응급구조학회지
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• 제15권2호
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• pp.67-84
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• 2011

Purpose: The aim of this study is to present the basic data for qualitative improvement of emergency care for emergency patient by paramedic in fire station by understanding the level of awareness and practice in prehospital and transfer step, and understanding the level of emergency care and improvement of clinical knowledge through hospital clinical training. Methods: The researchers explained the objective for 143 persons who completed hospital clinical training from June 2nd, 2006 to October 23rd, 2009 among paramedic in fire station. The questionnaire in this research consisted of 80 questions. In the reliability for the awareness of emergency patient assessment, cronbach's $\alpha$ was 0.95, and in the reliability for emergency care fulfillment, cronbach's $\alpha$ was 0.93. reliability for clinical knowledge improvement is cronbach's $\alpha=.95$, and reliability for emergency care fulfillment is cronbach's $\alpha=.82$. Collected data was analyzed through SPSS 18.0 statistics program for frequency, percentage, average, standard deviation, Paired t-test, t-test, Correlation Coefficient, and internal consistency reliability was analyzed by cronbach's $\alpha$. Results: 1) The paramedic awareness and practice difference for emergency patient is statistically signification for general patient assessment(t=14.159, p=.000), trauma patient assessment(t=11.288, p=.000), internal medicine patient assessment(t=10.898, p=.000), and it shows the level of practice is lower than the level of awareness. 2) The paramedic difference between the level of awareness and practice according to whether or not they have clinical career is not signification on awareness(t=3.119, p=.125), and is high on practice(t=3.119, p=.002). 3) The correlation between paramedic awareness and the level of practice shows positive correlation(r=.61, p=.000). The higher the awareness of emergency patient assessment is, the higher the level of practice is. 4) The difference between paramedic clinical knowledge improvement and the level of emergency care practice is statistically significant(t=3.351, p=.001). 5) 89.6%(128 persons) of paramedic replied hospital clinical training experiences are helpful for field activity. 92.3%(133 persons) replied they apply well for clinical knowledge learned during hospital clinical training and emergency care skills in the field. Conclusion: Paramedic in fire station must evaluate the patient's initial assessment and activate the transfer system to the emergency department. It is necessary to develop and implement the effective education program continuously. The education program should systemize currently operated hospital clinical training. emergency disease and symptoms emergency care method, and practice mainly skill education should be progressed. In the prehospital and transfer management, high quality of medical assessment is required to the emergency medical service system. Medical direction from the doctors can feedback the paramedic continuously and continuing education must be provided to the paramedic in fire station.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2209-2214
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• 2010

The purpose of Reliability Centered Maintenance(Hereafter, RCM) is to enhance the effectiveness and efficiency of preventive maintenance by applying the improvement plan after analysis of existing preventive maintenance. To accomplish this, it is required to collect the failure data for equipments during operation, and to carry out the quantitative criticality analysis for each equipment. This paper shows that the case study of RCM criticality analysis based on the accumulative failure data and following improvement activity for KORAIL AIRPORT RAILROAD's E&M system.

• 대한안전경영과학회지
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• 제2권3호
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• pp.141-150
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• 2000

This study aim is analysis device development for design of experiment with calcium chloride relation used a hardener to search cause of product crack, product reliability improvement building data-base program for computer system of mixture rate, product improvement, and new product development.

• 한국융합학회논문지
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• 제9권7호
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• pp.223-230
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• 2018

장시간 저장되어 있다가 사용되는 일회성 군수장비 시스템의 경우, 저장 시간이 지남에 따라 저장신뢰도에 변화가 발생하게 된다. 이에 사용시점이 도래하였을 때 제품 사용에 있어 저장신뢰도가 중요한 품질특성으로 작용하게 되며, 기존의 연구들은 저장신뢰도 향상을 위하여 최적의 정기검사주기 산출을 위한 연구에 초점이 맞춰져 있었다. 본 연구에서는 정기검사주기 뿐 아니라 설계신뢰도를 포함한 분석을 통해 융합적인 관점에서 저장신뢰도에 두 인자가 얼마나 영향을 미치는지 분석을 수행하였다. 이를 위해 일회성 시스템의 대표적인 제품인 유도탄에 기존의 Martinez 저장신뢰도 결정모델을 적용하여 각각 설계신뢰도와 정기검사주기가 미치는 정량적인 효과에 대하여 분석을 수행하였다. 분석 결과를 통해, 현 제품의 설계신뢰도 범주 내에서는 설계신뢰도보다는 정기검사주기 관리가 저장신뢰도 향상에 더 중요한 요인이라는 것을 확인해 볼 수 있었다.

• 품질경영학회지
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• 제45권4호
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• pp.981-994
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• 2017

Purpose: In this study, the reliability growth management procedures for armed vehicle is suggested and an illustrative case study of launcher system is given. Methods: Crow-AMSAA model is adopted to manage reliability growth of armed vehicle using failure data acquired from development test phase to field operation phase. Between the development test phase and the production phase, the suggested reliability growth procedures for armed vehicle entails accelerated life test of the selected module whose design is changed to improve its reliability for assuring the target system reliability. And it can be verified through estimating the system reliability based on the failure data of field operation phase. Results: It is shown that the proposed reliability growth management procedures are effective for armed vehicle based on the case study of launcher system. After estimating the reliability of launcher system at every development test, some items are selected to change their designs for improving reliability. Accelerated life test is performed to prove the reliability improvement and finally it is verified through the field operation. Conclusion: The reliability growth management procedures for armed vehicle is suggested and the case study of launcher system shows it can be effective for managing the reliability growth of the armed vehicle.

• 전기학회논문지P
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• 제64권4호
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• pp.297-302
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• 2015

Replacing a manual switch installed in a feeder for a distribution system with an automatic one increases the reliability of the electric power system. This is because the automatic switch can shorten the duration of a fault the customer experiences by splitting the faulty section faster than the manual one does. However, improving the reliability of the distribution system may increase investment costs. Here, the investment costs include automatic switch cost, replacement work cost and labor cost. For this reason, importance should be attached to the proper balance between the increase of the investment costs and the improvement of the reliability of the distribution system. This article analyzed reliability index and economics when manual switches installed in a feeder (RBTS Bus2 model) was replaced by automatic ones. In addition, it attempted to draw the optimum rate of automation of manual switches by automatic ones using the GRG optimization method, considering the current economic requirements.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권2호
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• pp.97-102
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• 2014

Radar is an object-detection system that uses radio waves to determine the range, altitude, direction, or speed of objects. High power amplifier Module is the most critical part of the high-power radar transmitter systems. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. Research related to radar has been conducted in various fields according to improvement of the communication technology. But only performance-originated technology development has been dashed; study concerning environment duality and safety concerning reliability are still insufficient. In general, radar module is exposed to the outside, on the means of moving or fixed in a certain place. It should be guaranteed sufficient immunity for a variety of environmental stresses that can occur in the outdoor. HALT is a great process used for quickly finding failure mechanisms in a hardware design and product. By applying various kinds and extreme level of stresses, we can find the operating limits of products. In thesis, we conducted HALT test of the high power amplifier modules which used in military and automotive radar. After the test, we analyzed environmental weaknesses of high power amplifier modules using conventional construction data.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권3호
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• pp.208-215
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• 2016

Purpose: ASRP for the domestic development guided missiles requires not only for the reliability evaluation of the products in storage but also for the life cycle management of the products including development prototypes and initial production items. Methods: For this purpose, it should be performed to build a performance database before and after the accelerated aging test with shelf life items including development prototypes and initial production items, based on which the lifetime prediction should also be carried out. In addition, HILS must be applied for the acceptance test with the initial and follow-up production items, and also for ASRP for the long-term storage products in order to secure systematic quality assurance. Results: The results for the life cycle reliability Improving of domestic development of guided missiles are DB building of prescription Item performance, active application of HILS, Management associated with guided missiles life cycle and to Secure technology data about the introduction of foreign guided missiles. Conclusion: Furthermore, it is demanded that DTaQ, the managing agency of ASRP, actively take part in the process to maintain reliability engagement consistency over the life cycle of guided missiles.