• Korea journal of population studies
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• v.11 no.1
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• pp.1-13
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• 1988

This study examines the sampling bias that may have resulted from the large number of missing observations. Despite well-designed and reliable sampling procedures, the observed sample values in DSFH(Demographic Survey on Changes in Family and Household Structure, Japan) included many missing observations. The head administerd survey method of DSFH resulted in a large number of missing observations regarding characteristics of elderly non-head parents and their children. In addition, the response probability of a particular item in DSFH significantly differs by characteristics of elderly parents and their children. Furthermore, missing observations of many items occurred simultaneously. This complex pattern of missing observations critically limits the ability to produce an unbiased analysis. First, the large number of missing observations is likely to cause a misleading estimate of the standard error. Even worse, the possible dependency of missing observations on their latent values is likely to produce biased estimates of covariates. Two models are employed to solve the possible inference biases. First, EM algorithm is used to infer the missing values based on the knowledge of the association between the observed values and other covariates. Second, a selection model was employed given the suspicion that the probability of missing observations of proximity depends on its unobserved outcome.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.222-228
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• 2019

An extreme value analysis (EVA) is essential to obtain a design value for highly nonlinear variables such as long-term environmental data for wind and waves, and slamming or sloshing impact pressures. According to the extreme value theory (EVT), the extreme value distribution is derived by multiplying the initial cumulative distribution functions for independent and identically distributed (IID) random variables. However, in the position mooring of DNVGL, the sampled global maxima of the mooring line tension are assumed to be IID stochastic variables without checking their independence. The ITTC Recommended Procedures and Guidelines for Sloshing Model Tests never deal with the independence of the sampling data. Hence, a design value estimated without the IID check would be under- or over-estimated because of considering observations far away from a Weibull or generalized Pareto distribution (GPD) as outliers. In this study, the IID sampling data are first checked in an EVA. With no IID random variables, an automatic resampling scheme is recommended using the block maxima approach for a generalized extreme value (GEV) distribution and peaks-over-threshold (POT) approach for a GPD. A partial autocorrelation function (PACF) is used to check the IID variables. In this study, only one 5 h sample of sloshing test results was used for a feasibility study of the resampling IID variables approach. Based on this study, the resampling IID variables may reduce the number of outliers, and the statistically more appropriate design value could be achieved with independent samples.

• Journal of Korea Entertainment Industry Association
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• v.14 no.5
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• pp.103-114
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• 2020

The purpose of this study is to analyze the difference of the effect of adult golf participation on the exercise adherence through the exercise immersion and to suggest the adherence golf exercise. To achieve this purpose, 40~70 age subjects of adult golf club located in Gyeongsangnam-do jinju city were selected in January 2020 and sampled by systematic cluster random sampling. First, factor analysis and reliability analysis were conducted to secure validity and reliability. Second, the frequency analysis average(M) standard deviation(sd) were conducted to investigate the general characteristics of the respondents. Third, t-test and one-way ANOVA analysis were conducted to identify differences between exercise immersion and exercise adherence according to general characteristics. Fourth, correlation analysis and multiple regression analysis were conducted among variables. The results of this study through these methods and procedures are as follows. First, there was no significant difference in the exercise impression and exercise adherence of general characteristics. Second, exercise immersion showed a high difference in exercise adherence. Third, exercise immersion had a high effect on exercise adherence.

• International Journal of Advanced Culture Technology
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• v.11 no.4
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• pp.233-243
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• 2023

The purpose of this study is to determine the effect of horseback riding participation motivation on emotional style and subjective well-being. In order to achieve this research objective, adults aged 20 or older participating in equestrian clubs in Seoul, Jeolla-do, and Gyeonggi regions in 2022 were selected as the population. The sampling method used cluster random sampling, and a total of 250 people, 180 males and 120 females, were sampled. The survey tool was modified and supplemented for this study based on a questionnaire whose reliability and validity were verified in previous studies, and all questionnaire questions were structured on a 5-point scale. For data analysis, SPSS Windows 21.0 Version was used to perform statistical processing according to the purpose of analysis. The conclusions obtained in this study through data analysis according to these methods and procedures are as follows. First, the motivation to participate in horseback riding was found to partially affect emotional style. Second, the motivation to participate in horseback riding was found to partially affect subjective well-being. Third, the emotional style of horseback riding participants was found to partially affect subjective well-being. Considering these results, it is possible to satisfy various desires in modern people's lives through leisure sports activities such as horseback riding, which allows them to communicate with nature and living things. In other words, internal motivation factors such as social relationships, satisfaction of needs, and professional development through leisure sports activities are positively or negatively related to emotional regulation, and this has a close impact on satisfaction with one's life and happiness.

• Journal of Environmental Impact Assessment
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• v.17 no.4
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• pp.225-233
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• 2008

An Environmental Specimen Bank (ESB) is an archive for samples that can be used to document and assess the quality of the environment in which we live. An ESB program looks at changes in the concentration of human and environmental specimens over long periods of time through retrospective analysis of archived samples of a particular area collected at regular intervals. The idea of ESB was first proposed by German and American scientists in the early 1970s and has been established since 1979 in Germany, USA, and Japan. Korea plans to establish a National Environmental Specimen Bank (NESB) in 2010. The NESB will be able to assess and improve the quality of analytical measurements as well as to compare the past and current environmental quality as a time capsule. The concept and design for the NESB facility was developed and its Standard Operation Procedures (SOPs) are being developed based on an evaluation of ESBs and SOPs of Germany, USA, and Japan. Environmental specimens proposed for banking are based on typical representatives of every level of the food chain from each type of ecosystem that are widely distributed thus enabling comparisons between different sampling areas. Through retrospective analysis of environmental specimens, the NESB will improve the reliability of environmental monitoring, ecological risk assessment, and health impact assessment.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1125-1125
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• 2001

Micro-scale test methods are producing small-sample size where the conventional physical and chemical tests can not be used (high standard deviation, uncertain sampling conditions, low repeatability). Different small-scale test methods were developed recently for determination of physico-chemical, functional, rheological properties of wheat or wheat dough using miniaturized instruments with sophisticated sample preparation/handling and mechanics (RVA, 2 g mixograph, micro-Z-arm mixer, small-scale noodle maker, micro-baking method etc.). The small-scale methodologies can be used as basic research tools or as technology supported measurements and can be also essential in the early selection for quality traits in breeding programs. The milling as a sample preparation step is essential procedure providing good quality flour or semolina samples from small amount of grain (5-10 g) in a reproducible and reliable way. The aim of present study was to use NIR as quality control tool, and to evaluate the recently developed and manufactured micro-scale lab mill (FQC-2000) produced by Inter-Labor Co. Ltd., Hungary. The milling characteristics of the new instrument were compared to other laboratory mills and the effects of milling action on the chemical composition of fractions were analysed. The fractions were tested with both chemical and near infrared spectroscopic methods. The micro-scale milling resulted significantly different yields, particle size distributions and different fractions from compositional point of view. The near infrared spectra were sensitive enough to distinguish the fractions obtained by different milling procedures. Quantitative NIR calibration equations were developed and tested in order to measure the chemical composition of characteristic milling fractions. Special qualification procedure the PQS (Polar Qualification System) method was used for detecting the differences between fractions obtained by macro and micro-milling procedures. The results and the limitations of PQS method in this application will be discussed.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.138-145
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• 1983

The value of exfoliative sputum cytology in diagnosis of lung cancer has been accepted with bronchoscopic technique and results has been much improved by foreign investigators, but there was not presented accurate reports for sputum cytologic evaluation in Korea. We tried to find indicators of cytologic tests result in our hospital. During the period between May, 1980 and August, 1982, 400 patients, tested at Department of Thoracic and Cardiovascular Surgery of Kosin Medical College, had diagnostic bronchofiberscopic examination, and the cytologic study of sputum and bronchial secretions were performed. The sputum or bronchial secretion during bronchofiberscopic examination were obtained with various methods and the name of specimen were labeled as I, ASPIRATION SPUTUM, which was collected initially endobronchial sputum as introducing of scope, II, WASHING SPUTUM, which was collected washing bronchial secretion, III, BRUSHING SPUTUM, which was washing solution of brushing instrument and endobronchial sputum after brushing of lesions, IV, POST-SCOPIC SPUTUM, which was expectorated sputum as soon as removing of scopic instrument, V, ALL SPUTUM CYTOLOGY & CELL BLOCK, which was collected all specimen of above procedures. The diagnostic results of bronchofiberscopic examination was disclosed 174 cases [43.5%] of proved lung cancer, 47 cases [11.8%] of suspected lung cancer in grossly, and 179 cases [44.8%] of others finding except cancer. Patient with bronchofiberscopically grossly evidence of lung cancer which were not confirmed histologically or cytologically were excluded from this cytologic study. Histologic and cytologic correlation in proven lung cancer, 174 cases was revealed that number of cytologic positive patients were 45 cases [38.7%] among the 117 cases of proved squamous cell carcinoma, 12 cases [38.7%] among hislogically unknown cancer 34 cases and 6 cases [33.3%] among small cell undifferentiated carcinoma 18 Gases. Total cytologic positive result was presented as 67 cases [38.3%]. The other type of lung cancer, histologically, could not comparison because of small cases. The sequence of positive cytologic result in I-V specimen were disclosed as II, WASHING SPUTUM 57.6%, and V, ALL SPUTUM & CELL BLOCK 41.4%. The I, III & IV result were 28.6%, 22.2% and 26.1% respectively.

• The Korean Journal of Applied Statistics
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• v.24 no.4
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• pp.657-676
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• 2011

Properties of statistical process control procedures may not be derived analytically in many cases; however, the application of a Markov chain can solve such problems. This article shows how to derive the properties of the process control procedures using the generated Markov chains when the control statistic satisfies the Markov property. Markov chain approaches that appear in the literature (such as the statistical design and economic design of the control chart as well as the variable sampling rate design) are reviewed along with the introduction of research results for application to a new control procedure and reset chart. The joint application of a Markov chain approach and analytical solutions (when available) can guarantee the correct derivation of the properties. A Markov chain approach is recommended over simulation studies due to its precise derivation of properties and short calculation times.

• Journal of Environmental Impact Assessment
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• v.21 no.2
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• pp.327-338
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• 2012

Environmental specimen banks provide the baselines for the scientists and decision makers to do research using the past and present specimens to expect the possible contaminant implications of the future. Many chemicals that are considered harmless now but not found may be found and pose threats in the future. Collected specimens of animals and plants should be conserved without contamination for future analysis. To ensure the availability of samples for the retrospective analysis, the establishment and maintenance of specimen banks in the developing and developed nations has become absolutely necessary. National Environmental Specimen Bank (NESB) established at National Institute of Environmental Research (NIER) in 2009. For the application of NESB, several activities such as standard operating procedures (SOPs) development have been prepared. This study applied the guidelines for sampling and sample treatment of five environmental specimens which had been prepared from 2007 to 2009. The target species were shoots of red pine and Korean pine, leaves of Mongolian oak, eggs of domestic pigeon and muscles and livers of common carp. The NESB will enhance the quality of environmental assessment and environmental monitoring based on real time and retrospective analysis.

• The Korean Journal of Applied Statistics
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• v.34 no.4
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• pp.537-556
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• 2021

Properties of statistical process control procedures may not be derived analytically in many cases; however, the application of a Markov chain can solve such problems. This article shows how to derive the properties of the process control procedures using the generated Markov chains when the control statistic satisfies the Markov property. Markov chain approaches that appear in the literature (such as the statistical design and economic design of the control chart as well as the variable sampling rate design) are reviewed along with the introduction of research results for application to a new control procedure and reset chart. The joint application of a Markov chain approach and analytical solutions (when available) can guarantee the correct derivation of the properties. A Markov chain approach is recommended over simulation studies due to its precise derivation of properties and short calculation times.