• 한국국방경영분석학회지
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• 제35권3호
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• pp.31-45
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• 2009

시스템의 성능과 안전성을 보장하기 위해서는 개발 초기부터 신뢰도에 대한 연구가 이루어져야 한다. 시스템의 목표 신뢰도를 수립하고, 이를 달성하기 위하여 하부시스템 및 부분품에 신뢰도를 할당해야 한다. 시스템의 획득 및 개발에 있어서 성능이 우수하고 비용이 저렴하더라도 고장이 빈번하게 발생한다면 원활한 임무 수행에 많은 영향을 미치고, 막대한 운영유지비용이 소요될 것이다. 본 연구에서는 신뢰도 할당 모형과 운영 유지비용과의 관계를 알아보기 위하여 기존의 알려진 신뢰도 할당 모형들을 검토 및 평가하였다. 신뢰도 할당모형의 평가는 차기 개발 함정용 디젤 엔진을 대상으로 하였으며, 다양한 신뢰도 할당 모형에 목표 신뢰도를 고려하여 신뢰도를 할당하고, 현재 운영하는 함정용 디젤 엔진의 자료를 바탕으로 시뮬레이션을 수행하여 운영유지비용을 최소화하는 신뢰도 할당 모형을 선정하였다.

• International Journal of Reliability and Applications
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• 제11권1호
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• pp.55-67
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• 2010

There has been a recent upsurge in demand for the improvement of car reliability in the Northern American which is the primary market of South Korea automobile industry. It has been required that the warranty for transmission control unit for passenger cars directly related to passenger safety or security should be extended for 10 years and 160,000 km. In this paper, the test method for reliability and evaluation criteria is presented to evaluate the reliability on the automatic transmission controller. Reliability certification test can be roughly divided into two types: a quality test and life assessment test and a quality test can be subdivided into a basic performance test and environmental resistance test. There are 3 types of tests on the performance test for automatic transmission controller and environmental resistance test is composed of 14 items. Life test is performed with only the product passed this quality test. In this study, operation limit test at the high-temperatures, accelerated life test under specific temperature and accelerated life test for 2 or 3 stress levels are shown as a way for life test.

• 한국산학기술학회논문지
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• 제20권2호
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• pp.210-217
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• 2019

본 논문은 드림스타트 사업평가에 사용된 평가지표가 '평가분야 및 영역별 신뢰도가 있는지'와 '평가지표별 변별력이 있는지'를 분석하고자 하였다. 이를 살펴보기 위하여 2018년 드림스타트 사업운영 평가를 받은 126개 시군구의 평가 자료를 바탕으로 실증적인 분석을 하였다. 연구결과는 첫째, 평가영역별 신뢰도를 살펴본 결과, 기본구성, 통합사례관리, 서비스 운영의 평가지표에 대한 신뢰도가 .6 이상으로 하위 평가지표들이 상위 평가분야와 같은 개념으로 볼 수 있는 최소기준을 충족하였다. 그러나 자원 개발 및 연계 분야는 신뢰도가 낮게 파악되었다. 평가영역별로 보면, 통합사례관리 분야에서 사례관리 과정에 대한 하위 평가지표의 신뢰도는 높았으나 기본구성 분야에서 사업운영 체계, 전담조직 및 인력을 확인하는 평가지표간의 신뢰도가 낮았고, 사례회의, 서비스 운영을 확인할 수 있는 하위 지표 간의 신뢰도가 낮게 나타났다. 둘째, 평가지표별 변별력을 측정한 결과, 28개 지표 중 18개 지표는 변별력이 높은 것으로 분석되었다. 반면 10개 지표는 변별력이 낮은 것으로 나타났다.

• 항공우주시스템공학회지
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• 제15권4호
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• pp.57-63
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• 2021

The launch vehicle (LV) separation detection interface of the satellite, which is designed to initiate the launch and early operation phase (LEOP) for S-band data transmission and the solar array deployment after the LV separation, is one of the hazard items at the launch site. Therefore, this interface should satisfy the single-fault tolerance requirement for the range safety. In this paper, we discuss the LV separation detection interfaces for two different satellite launch configurations and propose a method to guarantee for the satellite to start the LEOP even under the emergency case such as a partial separation from the LV. Furthermore, the proposed method meets the range safety requirement of the launch site. As this method only changes the external harness configuration of the satellite, it increases the reliability of the satellite early operation without any modification of the existing internal logics to detect the separation event.

• Journal of Welding and Joining
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• 제20권3호
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• pp.31-36
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• 2002

• 한국항공우주학회지
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• 제43권4호
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• pp.334-340
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• 2015

로켓 엔진을 설계추력보다 낮은 추력으로 운용하면 신뢰도가 증가하는 것으로 알려져 있다. 따라서 엔진을 디레이팅하여 증가하는 신뢰도가 엔진을 과설계하기 위해 증가된 개발비를 상쇄할 수 있다면 개발비를 최소화하기 위해 엔진의 과설계를 고려할 수 있다. 본 연구의 목적은 엔진 과설계와 디레이팅이 신뢰도 및 비용에 미치는 영향을 설명하는 모형을 개발하고자 하는 것이다. 타이탄 로켓 엔진의 운용추력수준 및 연소시험횟수에 따른 신뢰도 자료에 로지스틱 회귀모형을 적합하여 신뢰도 성장을 모형화하고 Transcost 비용모형을 이용하여 엔진을 10% 과설계 하면 신뢰도 요구값에 따라 엔진 개발비를 9%에서 23% 감소시킬 수 있음을 보였다. 또한 이러한 엔진 개발비의 감소는 엔진이 사용하는 연료에 따라 달라짐을 지적하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권4호
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• pp.296-304
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• 2017

Purpose: Recent weapon systems in defense have increased the complexity and importance of software when developing multifunctional equipment. In this study, we analyze the accuracy of the proposed software reliability model when applied to weapon systems. Methods: Determine the similarity between software reliability analysis results (prediction/estimation) utilizing data from developing weapon systems and system failures data during operation of weapon systems. Results: In case of a software reliability prediction model, the predicted failure rate was higher than the actual failure rate, and the estimation model was consistent with actual failure history data. Conclusion: The software prediction model needs to adjust the variables that are appropriate for the domestic weapon system environment. As the reliability of software is increasingly important in the defense industry, continuous efforts are needed to ensure accurate reliability analysis in the development of weapon systems.

• 산업경영시스템학회지
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• 제46권1호
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• pp.48-54
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• 2023

Guided missiles are a one-shot system that finishes their purpose after being used once, and due to the long-term storage until launch, the storage reliability is calculated during development, and performance is maintained through periodic inspections until the life cycle arrives. However, the reliability standards applied in the development of guided missiles were established by analyzing data accumulated by the United States during long-term operation in the country, and since they are different from our environment, the 00 guided missiles that have been deployed in the armed forces for more than 10 years under the premise that there is a difference from actual reliability. As a result of verifying the appropriateness of the current inspection cycle by analyzing the actual reliability of the missile, the necessity of changing the inspection period was derived because it was higher than the predicted reliability. It is proposed to build and utilize a lifespan management system that can systematically collect all data such as shooting and maintenance results by classification, and to establish a reliable reliability standard based on the accumulated data.

• 전기학회논문지
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• 제62권8호
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• pp.1177-1183
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• 2013

In this paper, the analysis of inspection period bases on reliability is suggested in the field of traction power system. Even though there are several maintenance models, the most commonly used maintenance assessment has been focused on time based maintenance in real traction power systems. The maintenance intervals are selected on the basis of long-time experience. It ensures high availability and exact planning of staff. Reliability centered maintenance, which evaluates criticality and severity of each failure mode, achieves the operation, maintenance, and cost-effective improvement that will manage the risks of equipment. This paper deals with electrification in railway inspection frequency and applied reliability based inspection frequency instead of constant intervals. The distribution function of failure rate in traction power system belongs to Weibull function. Also, the fault data and the number of installed equipments for electrifications are collected. The failure history is investigated and classified in detail. Though these complicated procedures, it contribute to extend equipment lifetime and to reduce maintenance costs.

• 대한산업공학회지
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• 제39권2호
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• pp.90-98
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• 2013

The k-out-of-n system with mixed redundancy is defined as k-out-of-n system which both includes warm-standby and cold-standby components. In case that operating components in the system fail and the system needs quick transition of standby components to operation state, the k-out-of-n system with mixed redundancy is useful for decreasing system failure rate and operational cost. Reliability-Redundancy Optimization Problem (RROP) involves selection of components with multiple choices and redundancy levels for maximizing system reliability with constraints such as cost, weight, etc. A solution methodology by using harmony search algorithm for RROP of the k-out-of-n system with mixed redundancy to maximize system reliability was suggested in this study.