• 한국신뢰성학회지:신뢰성응용연구
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• 제18권3호
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• pp.271-279
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• 2018

Purpose: Probabilistic safety analysis was performed to enhance the safety and reliability of nuclear power plants because traditional deterministic approach has limitations in predicting the risk of failure by crack growth. The study introduces a probabilistic approach to establish a basis for probabilistic safety assessment of passive components. Methods: For probabilistic modeling of fatigue crack growth rate (FCGR), various FCGR tests were performed either under constant load amplitude or constant ${\Delta}K$ conditions by using heat treated X-750 at low temperature with adequate cathodic polarization. Bayesian inference was employed to update uncertainties of the FCGR model using additional information obtained from constant ${\Delta}K$ tests. Results: Four steps of Bayesian parameter updating were performed using constant ${\Delta}K$ test results. The standard deviation of the final posterior distribution was decreased by a factor of 10 comparing with that of the prior distribution. Conclusion: The method for developing a probabilistic crack growth model has been designed and demonstrated, in the paper. Alloy X-750 has been used for corrosion fatigue crack growth experiments and modeling. The uncertainties of parameters in the FCGR model were successfully reduced using the Bayesian inference whenever the updating was performed.

• Journal of Nutrition and Health
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• 제53권2호
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• pp.175-189
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• 2020

본 연구는 젊은 성인을 대상으로 영양정보이해력을 평가할 수 있는 측정도구를 개발하기 위해 수행되었다. 영양정보이해력 평가를 위한 예비문항으로서 우선 7개 영역 65문항이 개발되었다. 작성된 예비문항을 영양전문가 5인에게 자문을 받아 불필요한 문항을 삭제하여 7개 영역 52문항으로 압축시켰다. 영양전문가 패널 20인을 대상으로 내용타당도 검증을 하였으며, Lawshe가 제안한 CVR값을 구하여 내용타당도 검증에 활용하였다. 평가도구 최종 항목으로서 총 6개 영역, 즉 식생활지침, 영양과 건강, 영양소, 다섯가지 식품군 (식품구성자전거), 영양표시, 질병 예방을 위한 영양관리를 포괄하는 30문항이 완성되었다. 이 평가도구를 이용하여 서울과 경인지역에 거주하는 성인 211명을 대상으로 신뢰도를 검증하기 위해 2주 간격으로 검사-재검사 (test-retest)를 실시하였으며, ICC값 (0.64-0.86)과 Cronbach's α 계수(0.83-0.90)를 산출한 결과 모두 높은 수준으로 나타났다. 따라서 본 연구를 통해 개발된 도구는 영양정보이해력을 평가할 수 있는 적합한 내용을 담고 있으며, 신뢰도 또한 매우 높은 것으로 검증되어, 젊은 성인의 다양한 수준의 영양정보이해력을 판별할 수 있을 것으로 본다. 또한 본 연구를 통해 개발된 평가도구는 지역사회 영양중재 프로그램 계획 시 그리고 만성질환의 예방관리를 위한 영양교육을 위해 대상자의 영양정보이해력을 파악하는 진단도구로 활용될 수 있을 것이다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1549-1554
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• 2008

In this paper, The evaluation of durability of the PC Panel lining for tunnel structure was examined through the rapid test by carbonation and freezing and thawing. Also for the purpose of improvement of durability. Namely, the durable characteristics of PC Panel lining by carbonation and freezing and thawing, was evaluated by rapid test and long-term field exposure test and main influence factors were derived. As a result of test, Correlation of accelerating test in deterioration chamber and long-term field exposure test, it will be expected that the proposed correlation well to the prediction of life expectancy of structure and is contributed greatly in the future.

• 재활복지
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• 제21권1호
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• pp.27-46
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• 2017

본 연구의 목적은 시각장애인용 고용준비도 검사지를 개발하는 데 있다. 개발과정은 체계적인 개발절차에 따라 문헌연구를 통해 검사 요인을 구성하고, 학계 및 현장 전문가 의견조사, 파일럿 테스트를 통해 검사지를 최종 완성하였다. 검사지의 신뢰도와 타당도를 검증하기 위해 구직시각장애인을 대상으로 평가를 실시하여 253명의 평가 자료를 수집하였다. 검사도구의 신뢰도 및 타당도 검증을 위해 주성분 분석, 확인적 요인분석, 상관분석 등을 사용하였다. 신뢰도 분석결과, 구인별 신뢰도 계수는 0.88-0.92로 요인별 하위 문항 간 내적일관성이 양호한 것으로 확인되었다. 타당도 분석결과, 9개 구인별 주성분 요인분석에서 단일차원성이 양호하고, 확인적 요인분석 결과에서도 구조방정식 모형이 적합한 것으로 나타나 구인타당도는 양호한 것으로 평가되었다. 공인타당도 검증을 위해 고용준비도 검사와 직업스크리닝 검사 간 상관관계 분석을 실시한 결과, 상관계수값이 0.501로 나타나 공인타당도가 양호한 것으로 확인되었다. 이상의 결과에서, 시각장애인 고용준비도 검사는 평가도구로서 심리측정학적으로 타당성이 있는 것으로 확인되었다.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.926-939
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• 2022

The area of this study will cover the location-wise seismic response variation of an electrical cabinet in nuclear power point (NPP) based on classical reliability analysis. The location-based seismic ground motion (GM) selection is carried out with the help of probabilistic seismic hazard analysis using PSHRisktool, where the variation of reliability analysis can be understood from the relation between the reliability index and intensity measure. Two different approaches such as the first-order second moment method (FOSM) and Monte Carlo Simulation (MCS) are helped to evaluate and compare the reliability assessment of the cabinet. The cabinet is modeled with material uncertainty utilizing Steel01 as the material model and the fiber section modeling approach is considered to characterize the section's nonlinear reaction behavior. To verify the modal frequency, this study compares the FEM result with recorded data using Least-Squares Complex Exponential (LSCE) method from the impact hammer test. In spite of a few investigations, the main novelty of this study is to introduce the reader to check and compare the seismic reliability assessment variation in different seismic locations and for different earthquake levels. Alongside, the betterment can be found by comparing the result between two considered reliability estimation methods.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권3호
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• pp.238-244
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• 2016

Purpose: Domestic electric railway Regenerative Energy Storage System seriously affects the maintenance cost of the total operating expenses of nearly 60% of the total LCC (Life Cycle Cost) due to high dependence on foreign Leading company. Therefore by developing the system, it is important to lower the maintenance cost in the domestic supply. This study about the capacitor Reliability test and the purpose of this study is development electric railway Regenerative Energy Storage System. Methods: In case of, having a close relation between the temperature and the reaction rate, Accelerated Model was known that according to Arrhenius' law of chemical activity. If you apply this formula in using allowable temperature range of the capacitor can induce the Arrhenius empirical formula used in much Manufacture Fields. We evaluate the capacitors Leading company through the Arrhenius model. in order to providing a base for the localization of Ultra Capacitor. Conclusion: In this paper, we conducted a reliability test. And it was performed by the accelerated life test and Cycle Test with temperature and C-rate. and then MTBF and B10 life are estimated by analyzing the accelerated life test result. This is thought to need detailed study applying complex stress than about whether it matches the actual behavior in electric railway.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.531-532
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• 2007

• 대한기계학회논문집A
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• 제36권7호
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• pp.751-757
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• 2012

사용조건에서 수명시험을 수행할 경우 시험시간이 많이 소요되므로 사용조건보다 가혹한 스트레스 조건을 추가하여 가속수명시험을 수행하면 시험시간을 단축시킬 수 있다. 수명에 영향을 미치는 스트레스를 선정하여 각 스트레스의 사용조건과 가속조건에서 시험을 수행할 경우 가속 스트레스간에 교호작용이 존재할 수 있다. 그러나 기존의 연구에서는 2가지 이상의 가속 스트레스를 부과하여 가속수명시험을 수행할 경우 교호작용을 고려하지 않은 경우와 가속 수명에 대한 모델식을 제시한 연구들이 대부분이다. 본 논문에서는 기계류 부품의 수명에 영향을 미치는 가속 스트레스를 선정한 후 교호작용을 고려한 시험계획에 따라 가속수명시험을 수행한 자료를 이용하여 가속 계수와 가속 스트레스간의 관계식을 산출하는 방법을 제시하고자 한다. 또한 본 논문에서 제시한 교호작용을 고려한 가속시험방법과 가속 계수를 산출할 수 있는 모델식을 이용하여 복합적인 가속수명시험 수행시 쉽게 적용하고 결과를 산출할 수 있는 기초가 될 것으로 기대된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.196-203
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• 2008

Durability of geosynthetics for soil reinforcement is accounted for creep and creep rupture, installation damage and weathering, chemical and biological degradation. Among these, the long-term creep properties have been considered as the most important factors which are directly related to the failure of geosynthetic-reinforced soil(GRS). However, the creep test methods and strain limits are too various to compare the test results with each other. The most widely used test methods are conventional creep test, time-temperature superposition and stepped isothermal method as accelerated creep tests. Recently developed design guidelines recommend that creep-rupture curve be used to determine the creep reduction factor($RF_{CR}$) which is a conservative approach. In this study, the different creep test methods were compared and the creep reduction factors were estimated at different creep strain limits of 10% of total creep strain and creep rupture. In order to minimize the impact of creep strain to the GRS structures, the various creep reduction factors using different creep test methods should be investigated and then the most appropriated one should be selected for incorporating into the design.

• Safety and Health at Work
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• 제4권1호
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• pp.37-45
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• 2013

Objectives: As quality of work-life (QWL) among nurses affects both patient care and institutional standards, assessment regarding QWL for the profession is important. Work-related Quality of Life Scale (WRQOLS) is a reliable QWL assessment tool for the nursing profession. To develop a Chinese version of the WRQOLS-2 and to examine its psychometric properties as an instrument to assess QWL for the nursing profession in China. Methods: Forward and back translating procedures were used to develop the Chinese version of WRQOLS-2. Six nursing experts participated in content validity evaluation and 352 registered nurses (RNs) participated in the tests. After a two-week interval, 70 of the RNs were retested. Structural validity was examined by principal components analysis and the Cronbach's alphas calculated. The respective independent sample t-test and intra-class correlation coefficient were used to analyze known-group validity and test-retest reliability. Results: One item was rephrased for adaptation to Chinese organizational cultures. The content validity index of the scale was 0.98. Principal components analysis resulted in a seven-factor model, accounting for 62% of total variance, with Cronbach's alphas for subscales ranging from 0.71 to 0.88. Known-group validity was established in the assessment results of the participants in permanent employment vs. contract employment (t = 2.895, p < 0.01). Good test-retest reliability was observed (r = 0.88, p < 0.01). Conclusion: The translated Chinese version of the WRQOLS-2 has sufficient validity and reliability so that it can be used to evaluate the QWL among nurses in mainland China.