• Journal of the military operations research society of Korea
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• v.6 no.2
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• pp.129-149
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• 1980

In medical follow-up, equipment lifetesting, various military situations, and other fields, one often desires to calculate survival probability as a function of time, p(t). If the observer is able to record the time of occurrence of the event of interest (called a 'death'), then an empirical, non-parametric estimate may simply by obtained from the fraction of survivors after various elapsed times. The estimation is more complicated when the data are truncated, i.e., when the observer loses track of some individuals before death occurs. The product-limit method of Kaplan and Meier is one way of estimating p(t) when the mechanism causing truncation is independent of the mechanism causing death. This paper proposes jackknife estimators of logistic trans-formation and compares it to the product-limit method. A computer simulation is used to generate the times of death and truncation from a variety of assumed distributions.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.6
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• pp.641-652
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• 2012

This study took the conceptual framework of acculturation styles into the empirical investigation of international students in Korea. This research identifies the differences in acculturation styles, the characteristics of each segment, the effect of acculturation styles on clothing involvement (clothing involvement and risk probability), and the effect of cultural orientation values (individualism and collectivism) as covariates. The participants were international students attending a university located in Seoul. Data from 153 international students were used for statistical analysis. Respondents were grouped into four acculturation styles (integration, assimilation, separation, and marginalization). The assimilation group had the highest mean score of clothing interest. Cultural orientation values showed a significant covariate effect. With individualism as covariates, the main effect of acculturation styles on clothing interest was significant. In clothing product evaluation criteria, the integration group regarded design, fit and trend as most important. The marginalization group showed a mean score that was significantly lower in brand preference and satisfaction; however, the assimilation group had a mean score that was significantly higher.

• Journal of the Korean Mathematical Society
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• v.38 no.5
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• pp.1047-1059
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• 2001

The classical Geometric Brownian motion (GBM) model for the price of a risky asset, from which the huge financial derivatives industry has developed, stipulates that the log returns are iid Gaussian. however, typical log returns data show a distribution with much higher peaks and heavier tails than the Gaussian as well as evidence of strong and persistent dependence. In this paper we describe a simple replacement for GBM, a fractal activity time Geometric Brownian motion (FATGBM) model based on fractal activity time which readily explains these observed features in the data. Consequences of the model are explained, and examples are given to illustrate how the self-similar scaling properties of the activity time check out in practice.

• Environmental Analysis Health and Toxicology
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• v.14 no.1_2
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• pp.65-73
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• 1999

Dioxins refer to a family of chemicals comprising 75 polychlorinated dibenzo-p-dioxin (PCDD) and 135 polychlorinated dibenzo-p-furan (PCDF) congeners, which may cause skin disorder, human immune system disruption, birth defects, severe hormonal imbalance, and cancer. The effects of exposure of dioxin-like compounds such as PCBs are mediated by binding to the aryl hydrocarbon receptor (AHR), which is a ligand-activated transcription factor. To grasp physicochemical factors affecting human toxicity of dioxins, six geometrical and topological indices, eleven thermodynamic variables, and quantum mechanical descriptors including ESP (electrostatic potential) were analyzed using QSAR and semi-empirical AM1 method. Planar dioxins with high lipophilicity and large surface tension show the probability that negative electrostatic potential in the lateral oxygen may make hydrogen bonding with DNA bases to be a carcinogen.

• Culinary science and hospitality research
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• v.6 no.3
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• pp.57-81
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• 2000

The purposes of this study and to develop the model to prove the structural relationship between service orientation and customer satisfaction, to find out the mediating variables between them, to survey and analyze their roles empirically, and to prove the probability of applying the strategic frame to all hotels in Korea. For these purposes. the author developed a structural model which consists of six variables. The data were collected from 7 hotels and analyzed with AMOS program. The findings can be summarized as follows : First, the higher customer expectation, the lower customer satisfaction. Second, the higher customer expectation, the higher customer perceived quality. Third, the higher customer perceived quality, the higher customer satisfaction. Fourth, the higher customer perceived quality, the higher customer perceived value. Sixth, the higher customer satisfaction, the lower customer complaint. Seventh, the higher customer satisfaction, the higher customer loyalty.

• Journal of Korean Society for Quality Management
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• v.31 no.4
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• pp.164-175
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• 2003

This paper investigates bootstrap confidence intervals of the process capability index(PCI) based on the expected loss derived from the empirical distribution function(EDF). The PCI based on the expected loss is too complex to derive its confidence interval analytically, so the bootstrap method is a good alternative. We propose three types of the bootstrap confidence interval; the standard bootstrap(SB), the percentile bootstrap(PB), and the acceleration biased­corrected percentile bootstrap(ABC). We also perform a comprehensive simulation study under various process distributions, in order to compare the accuracy of the coverage probability of the bootstrap confidence intervals. In most cases, the coverage probabilities of the bootstrap confidence intervals from the EDF PCI turned out to be more accurate than those from the PCI based on the normal distribution. It is expected that the bootstrap confidence intervals from the EDF PCI can be utilized in real processes where the true distribution family may not be known.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.622-625
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• 2004

This paper presents multi-source spatial data integration models based on probability theory for landslide hazard assessment. Four probabilistic models such as empirical likelihood ratio estimation, logistic regression, generalized additive and predictive discriminant models are proposed and applied. The models proposed here are theoretically based on statistical relationships between landslide occurrences and input spatial data sets. Those models especially have the advantage of direct use of continuous data without any information loss. A case study from the Gangneung area, Korea was carried out to quantitatively assess those four models and to discuss operational issues.

• Wind and Structures
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• v.22 no.4
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• pp.393-408
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• 2016

Weibull distribution is a suitable distribution to use in modeling the life time data. It has been found to be a exact fit for the empirical distribution of the wind speed measurement samples. In brief this paper consist of important properties and characters of Weibull distribution. Also we discuss the application of Weibull distribution to wind speed measurements and derive an expression for the probability distribution of the power produced by a wind turbine at a fixed location, so that the modeling problem reduces to collecting data to estimate the three parameters of the Weibull distribution using Maximum likelihood Method.

• Korean Journal of Adult Nursing
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• v.16 no.1
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• pp.27-36
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• 2004

Purpose: The purpose of this study was to identify patterns and trends of hardiness studies and to suggest the direction of further research. Method : Forty-seven hardiness studies were collected through internet searching and were reviewed by some criteria. Result : The results showed that hardiness studies have increased rapidly since 1990's. Eighteen studies were thesis' for degrees and others were for non-degree research studies. All studies employed the non-experimental design, particularly correlational studies. In the sampling method, all studies used non-probability sampling. Most commonly used instrument for hardiness measurement was Pollock(1986)'s HRHS. In the majority of research, hardiness was treated both as a composite measure and 3 subscales. Hardiness-related concepts were 27 and classified into 5 categories such as health behavior, stress, adaptation, support, and others. Most common statistical technique was Pearson's correlation coefficient, followed by regression, ANOVA, path analysis. Conclusion : To be utilized as practical nursing knowledge, hardiness studies should be done with more empirical analysis such as experimental research, and Meta-analysis is needed to compare the effect size and significance of composit and 3 subscales of hardiness construct.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1125-1130
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• 2012

Objective: The objective of present study is to investigate the determinants of smoking behaviour among adults in Malaysia. Method: Findings of the Third National Health and Morbidity Survey (NHMS-3) by the Ministry of Health, Malaysia, were used. The sample consisted of 34,539 observations. A logistic regression model was thus applied to estimate the probability to participate in smoking. Results: Age, income, gender, marital status, ethnicity, employment status, residential area, education, lifestyle and health status were statistically significant in affecting the likelihood of smoking. Specifically, youngsters, low income earners, males, unmarried individuals, Malays, employed individuals, rural residents and primary educated individuals were more likely to smoke. Conclusion: In conclusion, socio-demographic, lifestyle and health factors have significant impacts on smoking participation in Malaysia. Based on these empirical findings, several policy implications are suggested.