• International Journal of Reliability and Applications
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• 제8권2호
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• pp.153-173
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• 2007

Wood-plastic composites (WPC) are gaining market share in the building industry because of durability/maintenance advantages of WPC over traditional wood products and because of the removal of chromated copper arsenate (CCA) pressure-treated wood from the market. In order to ensure continued market share growth, WPC manufacturers need greater focus on reliability, quality, and cost. The reliability methods outlined in this paper can be used to improve the quality of WPC and lower manufacturing costs by reducing raw material inputs and minimizing WPC waste. Statistical methods are described for analyzing stiffness (tangent modulus of elasticity: MOE) and flexural strength (modulus of rupture: MOR) test results on sampled WPC panels. Descriptive statistics, graphs, and reliability plots from these test data are presented and interpreted. Sources of variability in the MOE and MOR of WPC are suggested. The methods outlined may directly benefit WPC manufacturers through a better understanding of strength and stiffness measures, which can lead to process improvements and, ultimately, a superior WPC product with improved reliability, thereby creating greater customer satisfaction.

• 한국경제지리학회지
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• 제11권3호
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• pp.492-507
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• 2008

일반적으로 사용되는 많은 네트워크 분석방법들은 비공간적인 측면에서 네트워크를 인식하는 경향이 있다. 가령 네트워크의 신뢰성(reliability)을 측정하고 중요한 집합점(node)을 찾는 기본적인 문제에 있어서도, 이러한 분석방법들은 집합점의 속성이나 연결선(edge)의 거리와 같은 네트워크의 공간적인 요소를 배제한 채, 네트워크요소들의 위상적인 접합 여부만을 고려한다. 그에 따라 이러한 네트워크 분석은 실제 공간에서의 네트워크 특성을 반영하지 못하는 제한적인 결과만을 도출하게 한다. 그러나 본 연구는 국지네트워크의 자기상관 (local network autocorrelation measure) 값을 이용하여 이러한 문제의 해결을 시도하였다. 국가자기상관 값은 공간객체들의 유사성이나 군집성을 개별적으로 측정하여 각 객체들의 중요도를 나타낸다. 본 연구는 미국의 주요 인터넷 네트워크를 disjoint product method와 Getis-Ord의 G 수치를 이용하여 분석하였으며 그 과정에서 인구와 신뢰도를 변수로서 이용하였다. 그 결과 국지네트워크의 자기상관값은 주요한 집합점들의 국지적인 군집정도를 나타냈고, 이러한 연구 결과는 연구 촛점이 국지네트워크의 범위나 그 영향일 경우, 국지자기상관값의 이용이 더 실용적이고 현실적임을 보여준다.

• 지역사회간호학회지
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• 제32권4호
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• pp.415-429
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• 2021

Purpose: The purpose of this study was to develop the Self-Care Non-adherence Risk Assessment Scale (SCNRAS) for patients with chronic illness in South Korea. Methods: This study was conducted from April to July, 2020 and utilized a convenience sampling method to recruit 336 patients with chronic illness from three hospitals located in South Korea. The content, factorial structure, item-convergent/discriminant validity, convergent validity, internal consistency reliability, and test-retest reliability of the scale were evaluated. The data were analyzed using exploratory and confirmatory factor analyses, Pearson's correlation coefficient, Cronbach's α, and intra-class correlation coefficient. Results: The exploratory and confirmatory factor analyses yielded six-factors. Convergent validity was demonstrated using measures of defining issues. Internal consistency reliability and test-retest reliability were found to be acceptable, as indicated by a Cronbach's α of .65~.81 and an intra-class correlation coefficient of .93~.98. The Self-Care Non-adherence Risk Assessment Scale for patients with chronic illness is a new instrument that comprehensively measures the knowledge, skill, physical function status, access to health care, social support, motivation, and confidence. It comprises 18 items scored on a 5-point Likert scale. The validity and reliability of the scale were verified. Conclusion: The scale developed through this study is expected to screen those who need nursing intervention early by predicting the self-care non-adherence risk group.

• 감성과학
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• 제5권4호
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• pp.11-32
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• 2002

이 논문은 피로, 졸음, 각성, 기분 등과 같은 운전자 상태의 다양한 측면을 측정하기 위해 지상교통 분야에서 사용되어온 주관적 척도들을 평가한다. 구체적으로, 대표적인 주관적 측정 방법인 Epworth Sleepiness Scale, Karolinska Sleepiness Scale, Pearson and Byars Fatigue Checklist, Stanford Sleepiness Scale, Stress-Arousal Checklist 와 NPRU Mood Scale등이 신뢰성, 타당성, 민감성과 응용을 위한 적절성의 측면에서 비교 및 대조된다. 결론에서 이러한 주관적 척도들을 지상교통 분야에 응용하기 위한 제언이 논의된다.

• Journal of Information Technology Applications and Management
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• 제13권3호
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• pp.145-179
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• 2006

The measurement of informatization program effectiveness continues to be a central concern of both academics and practitioners. However, most studies of it have been inclined too heavily toward testing validity and reliability of evaluation measure to strengthen the theoretical rigor. Drawbacks of this approach have been pointed out as being unsuitable for evaluating the effectiveness of informatization program due to lack of practical relevance. The paper comprises four sections to solve the problem. 1) Through literature review of theoretical conceptual models in IS effectiveness and the domestic and foreign cases on informatization program, we establish the evaluation framework which consists of evaluation phases, 6 evaluation areas, and 22 evaluation items, and developed evaluation measures of each items. 2) Different researchers have addressed different aspects of attribute of measure. With comparing them to each other, 3 mutually exclusive criteria on coincidence analysis(usability of measurement. reliability of measurement. and validity of content) are identified. 3) Data are gathered from respondents in informatizaiton program-related organizations such as policy agency, management agency, support agency, and recipient agency. 4) The degree of coincidence of each evaluation measure are analyzed by course of an coincidence analysis procedure, which includes the reliability test, arithmetical test, and criteria validity test. The academic implication of this study is that researchers can gain an insight into the coincidence analysis to approach the problem of deciding on an indicator of performance for informatization program. There is also practical implication for applying the potential means of improving the practical relevance of conducting evaluating the informatization program.

• International Journal of Reliability and Applications
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• 제3권1호
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• pp.1-16
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• 2002

In reliability engineering, the bathtub-shaped hazard rates play an important role in survival analysis and many other applications as well. For the bathtub-shaped, initially the hazard rate decreases from a relatively high value due to manufacturing defects or infant mortality to a relatively stable middle useful life value and then slowly increases with the onset of old age or wear out. In this paper, we present a new two-parameter lifetime distribution function, called the Loglog distribution, with Vtub-shaped hazard rate function. We illustrate the usefulness of the new Vtub-shaped hazard rate function by evaluating the reliability of several helicopter parts based on the data obtained in the maintenance malfunction information reporting system database collected from October 1995 to September 1999. We develop the S-Plus add-in software tool, called Reliability and Safety Assessment (RSA), to calculate reliability measures include mean time to failure, mean residual function, and confidence Intervals of the two helicopter critical parts. We use the mean squared error to compare relative goodness of fit test of the distribution models include normal, lognormal, and Weibull within the two data sets. This research indicates that the result of the new Vtub-shaped hazard rate function is worth the extra function-complexity for a better relative fit. More application in broader validation of this conclusion is needed using other data sets for reliability modeling in a general industrial setting.

• Journal of information and communication convergence engineering
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• 제20권2호
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• pp.79-89
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• 2022

To compute the mean and variance of component-based reliability software, we focused on path-based reliability analysis. System reliability depends on the transition probabilities of components within a system and reliability of the individual components as basic input parameters. The uncertainty in these parameters is estimated from the test data of the corresponding components and arises from the software architecture, failure behaviors, software growth models etc. Typically, researchers perform Monte Carlo simulations to study uncertainty. Thus, we considered a Markov chain Monte Carlo (MCMC) simulation to calculate uncertainty, as it generates random samples through sequential methods. The MCMC approach determines the input parameters from the probability distribution, and then calculates the average approximate expectations for a reliability estimation. The comparison of different techniques for uncertainty analysis helps in selecting the most suitable technique based on data requirements and reliability measures related to the number of components.

• 한국산업정보학회논문지
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• 제12권1호
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• pp.80-86
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• 2007

The concept of the coverage has been played an important role in the area of reliability evaluation of a system. The widely used measures of reliability include the m time between failures, the availability and so on. In this paper, we propose an estimator of the coverage probability in a redundant system with a control unit and investigate some moments of the proposed estimator. And assuming exponential distribution of all units, we conduct a simulation study for calculating the estimates of the coverage probability and its confidence bounds. An example of evaluating the availability of an optical transportation system is illustrated.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.366-371
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• 1995

This paper is designed to bring to the attention of the reader the situation that may constitute a threat to the safety of RC structures designed and constructed in Korea. This threat stems from the inadequate rules of the acceptance strength control of concrete. As a result in some cases probability of brittle failure can be very high and reliability becomes very low. The paper substantiates the above statements. Further investigations aimed at finding the measures to remedy the situatuion are recommended.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2000년도 추계학술대회
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• pp.375-384
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• 2000

The main objective of this paper to purpose a evaluating methods of process capability measures for exponential distributed quality characteristics. For correctly evaluating process capability , the first thing , exponential data is applied the Lilliefors test statistic to the null hypothesis of nornality. The next, exponential parameters is estimated in terms of MLE , ME , MME and then evaluated , respectively , process capability index based on exponential curved (Ιe) proposed by in this study and process capability indices based on Pearson system and Johnson system.