• 한국신뢰성학회지:신뢰성응용연구
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• 제18권3호
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• pp.250-259
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• 2018

Purpose: Previously, missile reliability prediction is based on theoretical failure prediction model. It has shown that the predicted reliability is inadequate to real field data. Although an MTTF based reliability prediction method using real field data has recently been studied to overcome this issue. In this paper, we present a more realistic method, considering MTBF concept, to predict missile reliability. Methods: In this paper we proposed a modified survival model. This model is considering MTBF as its core concept, and failed missiles in the model are to be repaired and redeployed. We compared the modified model (MTBF) and the previous model (MTTF) in terms of fitness against the real failure data. Results: The reliability prediction result of MTBF based model is closer to fields failure data set than that of MTTF based model. Conclusion: The proposed MTBF concept is more fitted to real failure data of missile than MTTF concept. The methodology of this study can be applied to analyze field failure data of other similar missiles.

• 지역사회간호학회지
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• 제28권4호
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• pp.366-374
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• 2017

Purpose: The purpose of this study was to evaluate the validity and reliability of the Korean Version of the Nurses' Self-Concept Instrument (NSCI) geriatric hospital nurses in Korea. Methods: Bilingual nursing professionals performed translation and back-translation. Reliability and validity of the content and construction of the instrument were confirmed. Internal consistency reliability was determined. Construction and concurrent validity were verified using factor analysis and correlation coefficients. Results: The total 14 items for the Korean version of the Nurses' Self-Concept Instrument (NSCI) were retained through item analysis. In explanatory factor analysis, four subcategories were proposed with their names of each factor: 'Leadership', 'Staff relation', 'Knowledge', and 'Care'. The four factors accounted for 78.81% of the variances. The Cronbach's ${\alpha}$ regarding internal consistency were .77~.91 for the NSCI subscales. Correlation among four subcategories ranged .62~.84. Conclusion: The findings show that the Korean version of the Nurses' Self-Concept Instrument is reliable and valid for measuring professional Self-Concept of geriatric hospital nurses in Korea.

• 한국신뢰성학회지:신뢰성응용연구
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• 제17권4호
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• pp.289-295
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• 2017

Purpose: This paper will focus on the reliability technological innovation following the emergence of industry 4.0 featured by convergence, connection and complexity. In the course of the process, the concept and application of 3R (Robustness, Redundancy, Resilience) are considered along with reliability in industry 4.0. Methods: Reliability paradigm-changes are presented to meet the purpose of keeping the desired function in Industry 4.0. And the introduction of resilience, a concept compromising reliability is to be suggested. Results: The necessity of the 3R (Robustness, Redundancy, Resilience) introduction is emphasized according to reliability paradigm-changes. Conclusion: Reliability, robustness, redundancy and resilience are not mutually exclusive. Ultimately, acquiring the resilience requires robustness, redundancy and fittable maintenance procedures.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.293-296
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• 2002

This paper discusses a software reliability model for the distributed s-PCT algorithm fur remote sensing applications. The distributed algorithm is designed based on a Manager-Worker threading concept and goes further to use redundancy to achieve fault tolerance. The paper provides a status report on our progress in developing the reliability concept and applying it to create a model for the distributed s-PCT In particular, we are interested ill the algorithm performance versus reliability.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.102-109
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• 2001

In order to take account of the statistical properties of probability variables used in the structural analysis, the conventional approach using the safety factor based on past experience usually estimated the safety of a structure. The real structures could only be analyzed with the error in estimation of loads, material characters and the dimensions of the members. But the errors should be considered systematically in the structural analysis. Structural safety could not precisely be appraised by the traditional structural design concept. Recently, new approach based on the probability concept has been applied to the assessment of structural safety using the reliability concept. Thus, the computer program by the Probabilistic FEM is developed by incorporating the probabilistic concept into the conventional FEM method. This paper estimated for the reliability of a plane stress structure by Advanced First-Order Second Moment method using von Mises, Tresca and Mohr-Coulomb failure criterions. The reliability index and failure probability of attained by the Monte Carlo Simulation method with the von Mises criterion were same as PFEM, but the Monte Carlo Simulation were very time-consuming. The variance of member thickness and load could influence the reliability and failure probability most sensitively among the design variables from the results of the parameter analysis. And proper failure criterion must be used to design safely.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(I)
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• pp.27-43
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• 2003

Reliability Lifecycle from Concept to In-Service Operation and Maintenance. Reliability management must consider - SAFETY - SERVICE REQUIREMENTS. Reliability targets/objectives can be specified at feasibility stage. Reliability analysis to support design process. Reliability assessment to support reliability growth or contractual demonstration. Maintenance optimisation to improve reliability during lifetime of operation. Lessons learnt incorporated into next generation of trains.

• 한국자동차공학회논문집
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• 제19권6호
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• pp.133-139
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• 2011

Maintaining adequate sealing in engine cylinder head is a crucial factor in engine design. Failure of engine operations occurs mainly owing to the leaking by decreased sealing pressure. Reliability-robustness concept is applied to the engine cylinder head system. Deterministic way to obtain engineering solution in CAE industry may not consider the effects of noises and disturbances experienced during operation. However, analytical reliability-robustness concept may make possible to reduce the sensitivity of system with noise factors. Influences of design factors including noise factors would be predicted in analytical way. Optimized design may be obtained by shrinking variability and shifting to design target. Three-dimensional finite element analyses have been performed to apply analytical reliability-robustness concept.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.309-314
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• 2007

Recently, the LRFD and the PSF based on structural reliability assessment have been applied to NPP designs in behalf of the conventional deterministic design methods. In the risk-informed structural integrity, it is especially possible to optimize design procedures considering cost, manufacturing and maintenance because the structural reliability concepts have confirmed the reliability for which a designer aims. Generally, in order to evaluate the PSF, the LRFD which is the design concept for evaluating safety factors respectively on the limit state function including load and resistance. This study certifies the concept and its applications of the PSF using the LRFD based on the structural reliability engineering.

• 한국강구조학회 논문집
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• 제14권2호
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• pp.365-373
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• 2002

이 논문에서는 교량의 수명을 예측하기 위한 시스템 신뢰성 이론이 설명되고, 생애 분포 함수를 이용하여 현존하는 교량의 잔존 수명을 예측하는 방법이 설명된다. 시스템 이론과 생애함수 (survivor functions) 를 이용하여 LIFETIME 이라는 프로그램을 개발하였다. Survivor functions은 주어진 시간 t에 대해 신뢰성을 산출한다. 이 프로그램을 이용하여 콜로라도주에 있는 교량의 수명을 예측하였다. 이 교량은 직렬과 병렬로 구성된 시스템으로 컴퓨터 모델링 되었으며 이 모델을 이용하여 시스템 파괴 확률을 시간에 대해 계산하였다.

• 대한수학교육학회지:학교수학
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• 제3권1호
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• pp.75-99
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• 2001

The purpose of this study is to develop concept map as a tool of performance assessment in mathematics and to conduct feasibility test of the task. I developed and applied a concept map, an assessment tool, in the form of a mathematics performance task for 1st and 2nd year middle school students. I also conducted feasibility test of the task, and at the same time sought ways to guarantee reliability of the assessment procedure. Results of the task assessment can be summarized into the following four points. First, the concept map task was found to be appropriate for an assessment of mathematics in middle school. Second, results of all 10 factors on verification of validity of the content of the task were positive with over 50%. Third reliability of teachers who conducted marking of the four concept map tasks was high, all recording over .871 in correlation number.