• 한국데이터정보과학회:학술대회논문집
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• 2006.04a
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• pp.181-187
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• 2006

In this paper we suggest a new alternative estimator for the characteristics that are pooly correlated with the selection probabilities by applying the Amahia et al.(1989)'s estimator to Rao-Hartley-Cochran sampling scheme and compare it with that of Rao(1966)'s under a super-population model.

• The Korean Journal of Applied Statistics
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• v.31 no.5
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• pp.621-636
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• 2018

Research on the application of informative sampling technique has been conducted in order to reduce the influence of non-response. Chung and Shin (Korean Journal of Applied Statistics, 30, 993-1004, 2017) showed that the estimation accuracy improved when using exponential response rate information for the parameter estimation if the distribution of errors included in the super population model follows normal distribution. However this method divides the stratum into equally spaced substrata to obtain the sample weight of the informative sampling technique and shows that the accuracy of the estimation improves as the number of substrata increases. In this study, with the given number of total sample size, the optimal substratum boundary points are calculated using equal space, quantile, and LH algorithm; consequently, the results using those methods are compared through simulation. We also studied the criteria to determine the number of substrata and substratum boundaries that can be used in practice with various types of auxiliary variable distributions.

• The Korean Journal of Applied Statistics
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• v.27 no.4
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• pp.645-653
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• 2014

P-value is the probability of observing a current sample and possibly other samples departing equally or more extremely from the null hypothesis toward postulated alternative hypothesis. When p-value is less than a certain level called ${\alpha}$(= 0:05), researchers claim that the alternative hypothesis is supported empirically. Unfortunately, some findings discovered in that way are not reproducible, partly because the p-value itself is a statistic vulnerable to random variation. Boos and Stefanski (2011) suggests calculating the upper limit of p-value in hypothesis testing, using a bootstrap predictive distribution. To determine the sample size of a replication study, this study proposes thought experiments by simulating boosted bootstrap samples of different sizes from given observations. The method is illustrated for the cases of two-group comparison and multiple linear regression. This study also addresses the reproducibility of the points in the given 95% confidence interval. Numerical examples show that the center point is covered by 95% confidence intervals generated from bootstrap resamples. However, end points are covered with a 50% chance. Hence this study draws the graph of the reproducibility rate for each parameter in the confidence interval.

• The Korean Journal of Applied Statistics
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• v.21 no.2
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• pp.313-325
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• 2008

Large amounts of information on individuals is available to many organizations and data users and government agencies release microdata files from their survey data or administrative records data. However, if a microdata file is released without any limitation, an invasion of privacy is likely to occur. Therefore, in creating a microdata file, agencies attempt to eliminate disclosure risk of the file while maintaining maximum utility of the data. In this paper, we introduce the concept of disclosure risk, identification and uniqueness. Also, we show the method for creating a 2% microdata file using the 2005 Korean census microdata.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.156-162
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• 2012

Outlier detection and treatment process is highly required as the first step for the statistical analysis of the monitoring data having many outliers frequently occurred in the coastal environmental monitoring projects. In this study, the outlier detection method using the approximate and detail (or residual) components of the (raw) data is suggested. The approximate and detail components of the data can be separated by the diverse filtering and smoothing methods. The decomposition of the data is carried out by the harmonic analysis and local regression curve, respectively. Then, the Grubbs' test and modified z-score method widely used to detect outliers in the data are applied to the detail components of the water temperature data. The new data set is reconstructed after removed the outliers detected by these methods. It can be shown that the suggested process is successfully applied to the outlier detection of the coastal water temperature monitoring data provided by the Real-time Information System for Aquaculture Environment, National Fisheries Research and Development Institute (NFRDI).

• The Korean Journal of Applied Statistics
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• v.2 no.1
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• pp.1-17
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• 1989

本稿는 統計學의 理論 개척과 발전을 위해서 應用分野의 연구에 주력해야 할 필요성을 밝히려 한다. 우선 기존의 統計理論이 應用分野에서 生成 발전된 점을 밝히는 동시에 應用分野에 대한 연구의 관심을 확대시켜야 할 필요성을 설명하려 한다. 물론 數理統計學이나 確率論과 같은 分野는 論理的 硏究方法으로 數理解析의 발전이나 方法을 개척할 수가 있다. 그러나 그것도 人類의 福祉증진에 기여하게 된다는 최종적인 목적성이 전제된다면 현실의 應用分野와 결코 무관할 수는 없을 것이다. 이상과 같은 목적을 위해서 우선 統計學이 과학으로 성립하기 이전의 生成 배경을 설명하면서 統計學이 人間의 生活과 얼마나 밀접하고 그 대상이 얼마나 광범위한가에 대하여 설명하려 한다. 처음부터 그것은 個人生活보다는 集團生活과 더욱 밀접한 관계가 있었다는 점을 강조하게 된다. 그리고 20世紀初에 론돈大學의 生物測定硏究室, 겔톤優生學硏究室 등을 중심으로 한 웰든, 겔톤, 피어슨 그리고 네이만의 生物測定硏究와 數理統計學연구와 핏샤와 끄ㅅ 등의 연구업적에 의해서 統計學이 科學으로 성립된 歷史的 사실을 반취하면서 統計學의 연구방법과 대상을 간접적으로 인식하게 된다. 또 統計學이 他科學과 비교하여 硏究對象 方法 그리고 實踐的 側面에서의 學問的 特殊性을 설명하면서 統計學연구의 應用側面을 강조하게 된다. 끝으로 선구자들의 統計學연구방법과 태도를 조감하면서 어떻게 하면 새로운 統計的方法을 개척할 수 있고 또 他分理 연구에 기존의 統計的方法이 기여할 수 있는가의 方法을 탐색하게 될 것이다. 즉 專門硏究機關에서, 實務現場에서 새로운 硏究對象을 찾아 새 方法을 개척할 수 있는가 하는 문제를 論議하게 된다. 이러한 탐구는 모두 과거에 統計學발전에 기여한 여러 선구자들의 연구방법과 업적을 되새기면서 유도된다.격)개발에 관심을 가진 사람들이 모이는 일일 것이다. 통계분야에서도 몇가지 표준화 활동이 ISO 를 중심으로 진행되고 있다. 예를 들면 실험과 검증 결과의 표현과 해석, 표본추출 방법 등에 관한 것으로 이들은 통계의 응용분야에서 꼭 필요한 표준이다. 구체적인 예로서 우리나라 국민의 표준체위값을 설정하기 위하여 측정조사할 때 측정방법 뿐 아니라 표본추출 방법과 통계자료 처리과정의 표준화가 이루어 지지 않는다면 각 기관에서 조사 발표하는 체위관계 자료가 상이하여 국가기관의 통계자료에 대한 신뢰성이 저하되고 통계값을 이용하여 의류, 신발 등의 제품을 제조하는 산업계에 혼란을 야기시킬 수 있다. 본 고에서는 ISO의 활동을 정보처리 분야에 초점을 맞춰 간략하게 설명하고 통계분야의 국제 활동을 비전문가인 필자들이 아는대로 소개하는 한편 국내활동의 필요성을 강조하여 관련 기관, 학계 및 산업계 관련전문가들의 ISO 국내활동 참여를 제의하고자 한다.mes$E조합에서는 견층비율의 자잠에서, D$\times$F조합에서는 웅잠의 견층비율에서 비교적 높은 값을 나타내었다.

• Journal of The Korean Association of Information Education
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• v.24 no.3
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• pp.225-232
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• 2020

This study is to clarify how college students think about quality computer classes. Q methodology is applied to extract the subjective thinking of college students. After extracting the statements through students' interviews and advanced study, the 54 Q samples were selected. The P sample consisted of 50 college students. They performed Q sort against the Q sample questionnaire. The Q sort results were analyzed by performing QUANL program. As a result of the analysis, four types of perceptions of quality computer classes based on college students' ideas were extracted. There were no differences between male and female students, but there was a clear difference between general college and teacher's college students by type. The types were divided into four categories which we named as follows: is 'Value change-oriented class through creative problem-solving', is 'Improving computer application skills through the learner's competition', is 'Improving advanced computer technology with programming skills' and is 'Learner centered pleasant class'.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.4
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• pp.305-310
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• 1983

Spatial variability of infiltration rates of 96 samples from Hwadong SiCL was studied by using geostatistical concepts. The measurement was made at the nodes of the regular grid consisting of 12 rows and 8 columns. Sample spacing within rows and columns was 3 and 2 meters, respectively. This study illustrated the use of variogram as a tool to identify the degree of dependency of the infiltration rate on the distance between pairs of measurements and how to take advantage of this dependency. Fractile diagram showed that the distribution of observation was approximately normal. The range of the variogram was about 7.4 meters. The minimum number of samples necessary to reproduce the results similar to the 96 measured values was 8 to 10. Coefficients of theoretical variogram function for computing kriged values and kriged varionces of nuogget effect, slope, and range were 0.444 cm/day, 0.003 cm/day, and 7.4 m, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6A
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• pp.835-842
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• 2008

The response surface method (RSM) is widely adopted for the structural reliability analysis because of its numerical efficiency. However, the RSM is still time consuming for large-scale applications and sometimes shows large errors in the calculation of sensitivity of reliability index with respect to random variables. Therefore, this study proposes a new RSM in which moving least squares (MLS) approximation is applied. Least squares approximation generally used in the common RSM gives equal weight to the coefficients of the response surface function (RSF). On the other hand, The MLS approximation gives higher weight to the experimental points closer to the design point, which yields the RSF more similar to the limit state at the design point. In the procedure of the proposed method, a linear RSF is constructed initially and then a quadratic RSF is formed using the axial experimental points selected from the reduced region where the design point is likely to exist. The RSF is updated successively by adding one more experimental point to the previously sampled experimental points. In order to demonstrate the effectiveness of the proposed method, mathematical problems and ten-bar truss are considered as numerical examples. As a result, the proposed method shows better accuracy and computational efficiency than the common RSM.

• Journal of Educational Research in Mathematics
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• v.21 no.1
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• pp.17-32
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• 2011

This study investigated pre-service teachers' understanding of statistical sampling. The researchers categorized major topics related to sampling into representativeness of samples, sampling variability, and sampling distribution, and selected concepts connected to each topic. Findings on this study are as follows: Even though most of the pre-service teachers considered the random sampling bringing unbiased outcomes as a proper sampling method, only 64% of them recognized that sample is a quasi-proportional, small-scale version of population; Few pre-service teachers understood that more important is the size of sample, not the portion of sample to population, and half of them appreciated that the number of sampling has a powerful effect on drawing of reliable results than the size of sample; Few pre-service teachers understood that sampling distribute is irrelevant to the shape of population and has a symmetrical bell-shape.