• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.8 s.251
• /
• pp.985-992
• /
• 2006

Many methods for reliability analysis have been studied and one of them, a moment method, has the advantage that it doesn't require sensitivities of performance functions. The moment method for reliability analysis requires the first four moments of a performance function and then Pearson system is used for the probability of failure where the accuracy of the probability of failure greatly depends on that of the first four moments. But it is generally impossible to assess them analytically for multidimensional functions, and numerical integration is mainly used to estimate the moment. However, numerical integration requires many function evaluations and in case of involving finite element analyses, the calculation of the first fo 따 moments is very time-consuming. To solve the problem, this research proposes a new method of approximating the first four moments based on kriging metamodel. The proposed method substitutes the kriging metamodel for the performance function and can also evaluate the accuracy of the calculated moments adjusting the approximation range. Numerical examples show the proposed method can approximate the moments accurately with the less function evaluations and evaluate the accuracy of the calculated moments.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.4
• /
• pp.1285-1288
• /
• 2012

Background: The Fagerstrom Test for Cigarette Dependence (FTCD) (formally FTND) is widely used for measuring physical dependence on nicotine. Objective: To explore the cross cultural validity and reliability of FTCD amongst Arabic speaker cigarette consumers who chew khat leaf, a stimulant green leaf. Methods: The psychometric properties of the FTCD were assessed in a subsample (91regular cigarette smokers) of purposively selected 204 UK-resident Yemeni khat chewers recruited during random visits to khat sale outlets. Data were collected via a structured face-to-face interview. Data analyses included descriptive tests and factor analysis. Results: Two factors were obtained by a principle axis factor analysis and these were termed as urgency of restoring the level of nicotine after abstinence during sleeping and maintaining the level of nicotine during waking. The internal reliability (Cronbach's alpha coefficient) of the whole FTCD is low (.68) as well as for the two subscales (.60) and (.62) respectively. Conclusion: The psychometric properties of the Arabic version of the FTCD scale in this sample of Yemeni khat chewers who smoked regularly confirmed what has been established in other cultural settings. The findings of this study have yet to be cross validated amongst other appropriately representative sample of Arabic speakers.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.13 no.1
• /
• pp.9-17
• /
• 2001

A probability of failure of armor units on rubbJe-mound breakwater are evaluated by using the direct method for reliability analysis, which is represented as a function of safety factor that has been extensively used in practical design. The reliability function is fonnulated based on Hudson formula suggested for designing the stable size of armor units on rubble-mound breakwater. Several kinds of stability coefficient are applied separately to calculate the probability of failure with respect to the type of armor units, breaking/nonbreaking and the correlation coefficients between random variables. [n addition, the sensitivity analyses are carried out to investigate quantitatively into the effects of each random variable in the reliability function on the probability of failure.

• Proceedings of the Korean Reliability Society Conference
• /
• 2004.07a
• /
• pp.239-246
• /
• 2004

Accelerated degradation test (ADT) can be a useful tool for assessing the reliability when few or even no failure are expected in an accelerated life test. In this paper, MLCC (Multilayer Ceramic Capacitors), a sort of passive components which have large capacitance(X7R -55$^{\circ}C$~1$25^{\circ}C$) have been tested, and least-square analyses are used to illustrate our approach in which amount of degradation of a DUT following log-normal distribution. We assumed a simple and useful linear model to describe the amount of degradation over time subjected to different voltage levels applied. Tests for linearity of the performance-time relationship, and provide tests for how well the assumptions hold. Also, by using Eyring Model, MLCC's mean life time is assessed.

• Culinary science and hospitality research
• /
• v.11 no.3 s.26
• /
• pp.40-55
• /
• 2005

The purpose of this study was to understand the effect of customers' repurchase intention, extract important factors, systematically analyze them and suggest the direction of bakery industry through studying the customers' satisfaction with bakeries. The researcher modified the questionnaire developed by Park, CH(1998), Lee, JH(2000), Yoon, YC(2000), and Kim SE(2002). In order to assess the level of customers' satisfaction with bakeries, a five point Likert scale was used. The used statistical methods for the data analysis were frequency analysis, reliability analysis, t-test factor analysis, ANOVA, multiple regression analysis. For all analyses of the research question, an alpha level of.05 was used. The major findings obtained from this study were as fellows. First on the factors of reliability and service ability, there was a high difference between males and females, and singles and the married. Second, on the factors of accessibility using convenience, service ability, and service response, there was a high difference among using frequence. Third, on the reliability factors, there was a high difference among average using amount per month. Forth, on the factors of accessibility using convenience, and service response, there was a high difference among types of customers' residing styles. Fifth, on the factors of income level, there was statistically no difference. Lastly, on the factors of accessibility using convenience, tangibleness, and service response, these factors significantly influenced customers' repurchase intention.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.6 no.1
• /
• pp.131-140
• /
• 2002

In this paper, a limit state model based on the analysis of structural behavior of segmental prestressed concrete box girder bridges and reliability-based safety assessment method are proposed for the bridges erected by free cantilever method. Strength limit state models for prestressed concrete box girder and rigid-frame type columns are developed for a structural safety assessment during construction. Based on the proposed limit state models, the reliability of the bridge is evaluated by using the Advanced First Order Second Moment method. The proposed model and method are applied to the Seo-Hae Grand Bridge built by FCM in order to verify its effectiveness in the safety assessment during construction of the kind of bridges. The sensitivity analyses of the main parameters are also performed in order to identify the important factors that need to be controlled for the safety of the bridges during construction.

• The Journal of Pediatrics of Korean Medicine
• /
• v.27 no.2
• /
• pp.31-47
• /
• 2013

Objectives This study was done to confirm reliability, validity and the internal structure of the Korean Medicine Satisfaction Questionnaire(KMSQ). Methods 154 parents who visited in Department of Pediatrics of Korean Medicine, University Hospital participated in this study. They were statistically analyzed by using PASW Statistics 20.0K for Windows. Results Factor analyses were largely divided into six categories such as Hospital, Waiting & Consultation Time, Doctor, Medicine, Therapy, and Cost. The validity and reliability of KMSQ were favorable. The highest average score of satisfaction was Doctor category as $4.20{\pm}0.51$ and the lowest one was Cost as $3.33{\pm}0.71$. The six factors showed highly positive relationship from correlation analysis. The result of comparative study on parent's demographic characteristics showed only one significant difference in satisfaction of Doctor within occupation. The result of comparative study on child's demographic characteristics showed significantly different in satisfaction of Therapy within gender, and of Medicine within age. Every average score of satisfaction showed somewhat difference within each section, and only 5.6% of them showed significantly difference in T-test. Conclusions Uses and research with the KMSQ as subjective tool in various department or medical institution are suggested.

• The Korean Journal of Health Service Management
• /
• v.13 no.4
• /
• pp.253-263
• /
• 2019

Objectives: This study evaluated the perception on importance of interprofessional core competencies (PI-ICCP) scale. Methods: Data were collected from 353 college students of health. Content validity was tested using the content validity index for individual items(I-CVI) and for scale(S-CVI). Criterion validity was tested using the professional competencies scale developed by Choi. Reliability was evaluated using Cronbach's coefficient alpha. The goodness-of-fit of the construct validity was determined through exploratory and confirmatory factor analyses. Results: The I-CVI of each item was .8 or higher for all items, and the S-CVI was .98. The reliability of the PI-IPCC was Cronbach's α=.98. The goodness-of-fit indices of the model were χ2=1811.54(p<.001), the comparative fit index (CFI)=.91, and root mean square error of approximation (RMSEA)=.08, which satisfied the criteria. Conclusions: The construct and criterion-related validity of the perception for PI-ICCP scale were a good fit, so the instrument is appropriate for measuring perception on importance of interprofessional core competencies. Further research will be required using this instrument to investigate perception of interprofessional core competencies of health professionals.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.3
• /
• pp.51-59
• /
• 2007

A reliability-based approach that can systematically model various sources of uncertainty is presented in the context of slope stability. Expressions for characterization of soil properties are developed in order to incorporate sampling errors, spatial variability and its effect of spatial averaging. Reliability analyses of slope stability with different statistical representations of soil properties show that the incorporation of sampling error, spatial correlation, and conditional simulation leads to significantly lower probability of failure than that obtained by using simple random variable approach. The results strongly suggest that the spatial variability and sampling error have to be properly incorporated in slope stability analysis.

• Journal of Families and Better Life
• /
• v.32 no.6
• /
• pp.31-45
• /
• 2014

The purpose of this study are to find out the gender and school level differences in adolescents' depression, and the influences of parent attachment and school stress on adolescents' depression and the effect of ego-resilience relations between parent attachment and depression, and that of school stress and depression. 402 of students(the first and the second graders of middle school and of high school in academic track in D area) completed questionnaire on parent attachment, school stress, ego-resilience, and depression. Descriptive statistic analyses, reliability analyses, Two-way ANOVAs, correlation analyses, and hierarchial multiple regression analyses were conducted through SPSS WIN 20.0. The findings are as follows. 1) There was school level difference, but not gender differences, on adolescents'depression. 2) There was ego-resilience control effect on the relations between parent attachment and adolescents' depression only for middle school students, but not for high school students. 3) There were ego-resilience control effect on the relations between school stress and adolescents' depression for both middle and high school students. The importance of ego-resilience and school levels in understanding adolescents' depression was discussed.