• Animal Systematics, Evolution and Diversity
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• v.21 no.2
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• pp.273-279
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• 2005

An examination of caddisfly materials from the field trips in Vietnam during 2002-2003 resulted in the recognition of the male adult of Tinodes reuse Malicky & Chantaramongkol(new Vietnamese record) and four undetermined species of larvae (Psychomyia VL1, Psychomyia VL2, Paduniella VL1, and Tinodes VL1) in the family Psychomyiidae Genera Psychomyia and Paduniella are recorded from Vietnam for the first time. Material data, descriptions, diagnoses, distributions, and taxonomic remarks are provided.

• 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.

• Communications for Statistical Applications and Methods
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• v.20 no.6
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• pp.439-454
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• 2013

This study presents a Bayesian multiple change-point detection approach to segment and classify the observations that no longer come from an initial population after a certain time. Inferences are based on the multiple change-points in a sequence of random variables where the probability distribution changes. Bayesian multiple change-point estimation is classifies each observation into a segment. We use a truncated Poisson distribution for the number of change-points and conjugate prior for the exponential family distributions. The Bayesian method can lead the unsupervised classification of discrete, continuous variables and multivariate vectors based on latent class models; therefore, the solution for change-points corresponds to the stochastic partitions of observed data. We demonstrate segmentation with real data.

• International Journal of Human Ecology
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• v.6 no.2
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• pp.51-61
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• 2005

This study investigated the allowance usage practices and factors affecting saving behavior from 291 elementary school students in Susan. Frequency distributions, Pearson product-moment correlations, and logistic regression analysis were conducted by SPSS Windows. Two-fifths of the respondents did not regularly receive allowance. Many parents did not guide what children spent their money on before using it. Children spent their allowances on buying snacks, stationary, and playing in the game room. Only a small number of the respondents kept a record, but many children saved money. On the other hand, in the logistic regression analysis, the significant variables explaining children's saving behavior were parents' guidance before using allowance, record-keeping, and doing household work for an allowance. These results imply that parents are in the best position to give children positive experiences towards financial management.

• Journal of Korean Society for Quality Management
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• v.31 no.1
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• pp.109-122
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• 2003

This paper presents a robust process capability index(PCI) based on the expected loss derived from the empirical distribution function(EDF). We propose the EDF expected loss in order to develop a PCI that does not depends on the underlying process distribution. The EDF expected loss depends only on the sample data, so the PCI based on it is robust and it does nor require complex calculations. The inverted normal loss function(INLF) is employed in order to overcome the drawback of the quadratic loss which may Increase unboundedly outside the specification limits. A comprehensive simulation study was performed under various process distributions, in order to compare the accuracy and the precision of the proposed PCI with those of the PCI based on the expected loss derived from the normal distribution. The proposed PCI turned out to be more accurate than the normal PCI in most cases, especially when the process distribution has high kurtosis or skewness. It is expected that the proposed PCI can be utilized In real processes where the true distribution family may not be known.

• The Korean Journal of Applied Statistics
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• v.9 no.1
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• pp.153-164
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• 1996

We discussed estimation of parameters using Gibbs sampler under order restriction on the parameters. Two well-knwon probability models, ordered exponential family and binomial distribution, are considered. We derived full conditional distributions(FCD) and also used one-for-one sampling algorithm to sample from the FCD's under order restrictions. Finally through two real data sets we compared three kinds of estimators; isotonic regression estimator, isotonic Bayesian estimator and the estimator using Gibbs sampler.

• Journal of Families and Better Life
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• v.19 no.2
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• pp.83-96
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• 2001

This study examined housework time management strategies between married female home-based workers and on-site workers, and found out the factors affecting the housework time management strategies. The data were collected from 165 married female home-based workers, and 292 married female on-site workers in Pusan and Kyungnam province, by self-administered questionnaire. Frequency distributions, Cronbachs alpha, t-tests, Pearsons correlations, and multiple regression analyses were conducted by SPSS/PC+. The major findings of this study were kas follows: 1) Married female home-based workers more used obtaining additional help and personal time reallocation than married female on-site workers. 2) For married female home-based workers, educational attainment and occupation were significant factors affecting housework time management strategies, and for married female on-site workers, employment hours per week and existence of elders/disability within the family were important variables.

• Survey Research
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• v.8 no.2
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• pp.1-19
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• 2007

This paper explores the extent to which property scale, in particular housing price is useful as the measure of an individual's economic status. Its main object is to compare the distributions of the measure of housing wealth and other objective or subject measures, i,e., reported income and subjective class identification. Additionally, their relations to other variables are examined. An analysis of distributions and cross-tables based upon national survey of 2005 family and the database of apartment price of Kookmin Bank are used. It is shown that the measure of housing wealth differs from other economic status measures in terms of distribution and the relations to other variables, such as attitude variables and consumption-related variables. Its results also suggest that the measure of housing wealth can be applied to various areas as a new measure of an individual's objective economic status, in such a way to improve applicability of social survey.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.160-160
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• 2023

Generally, Global Climate Models (GCM) cannot be used directly due to their inherent error arising from over or under-estimation of climate variables compared to the observed data. Several bias correction methods have been devised to solve this problem. Most of the traditional bias correction methods are one dimensional as they bias correct the climate variables separately. One such method is the Quantile Mapping method which builds a transfer function based on the statistical differences between the GCM and observed variables. Laux et al. introduced a copula-based method that bias corrects simulated climate data by employing not one but two different climate variables simultaneously and essentially extends the traditional one dimensional method into two dimensions. but it has some limitations. This study uses objective functions to address specifically, the limitations of Laux's methods on the Quantile Mapping method. The objective functions used were the observed rank correlation function, the observed moment function and the observed likelihood function. To illustrate the performance of this method, it is applied to ten GCMs for 20 stations in South Korea. The marginal distributions used were the Weibull, Gamma, Lognormal, Logistic and the Gumbel distributions. The tested copula family include most Archimedean copula families. Five performance metrics are used to evaluate the efficiency of this method, the Mean Square Error, Root Mean Square Error, Kolmogorov-Smirnov test, Percent Bias, Nash-Sutcliffe Efficiency and the Kullback Leibler Divergence. The results showed a significant improvement of Laux's method especially when maximizing the observed rank correlation function and when maximizing a combination of the observed rank correlation and observed moments functions for all GCMs in the validation period.

• Korean Journal of Social Welfare Studies
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• v.42 no.3
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• pp.233-265
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• 2011

Material hardship measures have been used to supplement the traditional income-based poverty measures. Recently poverty researchers have increasingly used measure of material hardship to examine the well-being of low income families. Measuring the material hardship might be useful to a better understanding of the multi-dimensions of the poverty in Korea. Using the data of the Korea Welfare Panel Study(the fourth wave), I examine incidences of material hardship across quintiles of the income distributions and the factors that might affect the experience of material hardship among the poor families. Major findings are as follows. Descriptive results show that nearly one-fifth of all families had experienced at least one of the five material hardships in the year. Those in the bottom quintiles and the poor families are more likely to experience material hardship than the other quintiles and non-poor families. But, incidences of the material hardship in the middle income quintiles and low income families are not a few(18 percent and 37 percent). Logistic regression results show that family-consumption related variables, income other economic resources(asset and public assistance), and household's employment status affect the experience of material hardship among the poor families. But, material hardship among the poor families is not significantly related with family income. These results indicate that material hardship measures are the useful indicators to understanding the multi-dimensions of the poverty in Korea. And they suggest that an extensive reform of the public assistance policy is necessary to relieve the material hardships of the poor in Korea.