• Journal of the Korean Data and Information Science Society
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• v.21 no.4
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• pp.669-679
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• 2010

A sample survey design is suggested for the service satisfaction evaluation of regional education offices based on the sample size of 2009 Gyeongnam regional education offices's customer satisfaction survey. The sample design is developed to fit the goal of evaluation of individual regional offices and allocate at least the minimum sample size to each city or county in Gyeongnam to achieve the goal of the survey. The population is stratified according to the regions and the types of schools, and the sample of schools is selected with proportional to the size of classes within each stratum. Finally, each sample student is selected according to two-stage cluster sampling within each sample school. Weighting averages, weighting totals and so on can be evaluated for analysis purposes. Their variance estimates can be evaluated using re-sampling methods like BBR, Jackknife, linearization-substitution methods, which are generally used for the data from a complex sample.

• Proceedings of the Korean Association for Survey Research Conference
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• 2002.06a
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• pp.74-84
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• 2002

본 연구에서는 1970년 Royall에 의해 표본추출방법의 한 대안으로서 다시 주목받기 시작한 균형추출방법(purposive selection or balanced sampling)과 확률추출방법(random sampling)의 장.단점을 층화추출법과 비추정량의 경우를 예로 들어 비교하고자 한다. 균형추출방법은 강건성(robustness)과 효율성(efficiency) 측면에서 확률추출방법은 추출의 간편성과 사회적 인식 측면에서 각각의 장점을 지니고 있는 것으로 볼 수 있다.

• Survey Research
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• v.11 no.3
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• pp.103-114
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• 2010

It is difficult to obtain the population information of target variables when a new sampling design for successive survey is executed. In a research of the Korea National Tourism Survey, we propose a method for selection of efficient stratification variables which are found in a combination of a existing sample data and a new frame list. At first, if there isn't common identification number between the frame list and the sample data, we find a device to substitute for absence of identification number. At second, we suggest a method to search stratification variables correlated with target variables using statistical methods like regression analysis.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.520-522
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• 2000

디지털영상을 상향표본추출(upsanpling)의 방법으로 확대하여 해상도를 높이는 경우에 확대한 영상은 확대 전의 영상에 비해 해상도는 높아지지만 흐려지거나 계단현상이 생기게 되어 영상의 품질은 저하된다. 본 연구에서는 확대된 영상에서 생기는 이와 같은 문제점을 보완하는 상향표본추출 모델을 제안한다. 제안된 모델은 8-이웃(8-neighborhood)과 가우시안 필터(Gaussian filter)를 이용하여 확대된 영상의 증가된 픽셀들의 픽셀값을 부여하여 확대 전 영상이 가진 특성이 확대 후에도 균질하게 유지될 수 있도록 하고 계단현상도 완화한다. 그리고 감마 교정(Gamma correction)을 이용하여 영상의 흐름 정도를 개선한다.

• The Korean Journal of Applied Statistics
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• v.10 no.2
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• pp.253-260
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• 1997

Various algorithms are investigated with respect to finding the best model-based samples according to criteria such as D-optimality and minimum mean square error. These two criteria are slightly different, but related to each other. Therefore, it is not surprising that these two are producing the almost identical samples. Some simple examples follow and critiques are provided along with directions for further research.

• The Korean Journal of Applied Statistics
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• v.13 no.1
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• pp.145-161
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• 2000

조사비용을 증대시키거나 조사실시에 어려움을 주는 바람직하지 않은 표본들의 추출확률을 줄여주기 위해서 Goodman과 Kish(1950)는 관리적 선정 방법을 제시하였다. 충화추출에서 표본의 수가 셀의 수보다 작은 경우 표본 배분에 문제가 발생한다. 이러한 문제를 해결하기 위해서 관리적 선정을 적용할 수 있는데 Causey 등 (1985)은 수송이론을 이용한 알고리즘을 제안하였고 Sitter와 Skinner(1994), Tiwaridh Nigam(1998)은 선형계획법을 이용하였다. 본 연구에서는 기존 방법들의 문제점들을 다루었으며 추출방법의 이론적 측면을 보완하기 위하여 표본들의 적합성을 고려한 관리적 선정을 제안한다. 아울러 분산을 최소화시키는 관리적 선정방법과 통합관리적 선정 방법도 제시하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.3
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• pp.101-107
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• 1982

The progressive sampling method adapts well to the local variabilities of the input terrains, and is therefore one of the most efficient sampling methods in DTM. The efficiency of progressive sampling can be enhanced by increasing the comprehensiveness of grid densification criteria, with superfluous points reduced and/or suppressed. In this investigation, four different criteria were applied to the numerical test, and the suppression criterion was found the most significant among them.

• Proceedings of the Korean Association for Survey Research Conference
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• 2000.11a
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• pp.157-168
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• 2000

In this paper we point out another advantage of systematic sampling over simple random sampling, which have not yet been spelled out in the literature. After a single sample is drawn by a sampling scheme, it is important to check whether the achived sample represents the population well or not. Therefore, a sampling scheme which avoids the possibility of selecting non-preferred samples is desirable. The simulation results are given to illustrate that, in the ordered population, the possibility of selecting non-preferred sample by systematic sampling is lower than that by simple random sampling.

• Asian Journal of Turfgrass Science
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• v.16 no.2
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• pp.97-106
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• 2002

The oriental beetle, Exomala orientalis, Is the most important insect pest of turfgrass in Korean golf courses. The study was carried out to get practical information on the sampling of E. orientalis in golf courses. Real numbers of E. orientalis larvae were compared with and observed numbers depending on sampling size (5$\times$5 cm, l0$\times$10 cm, 20$\times$20 cm, 30$\times$30 cm, and 40$\times$40 cm) and times (3 to 15 replicates) in Dongrae Benest Golf Club. Over 95% accuracy was obtained between real data and estimated data at the density of over 303 larvae/m$^2$ when the 20$\times$20 cm was sampled with 4 replications. Larval density of E. orientalis was different depending on year and course sites (tee, fairway, rough, green).

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.1093-1098
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• 1995

IAEA(International Atomic Energy Agency, 국제원자력기구)에서는 사찰활동 수행시, 비복원추출(sampling without replacement)을 기술하는 초기하분포 대신 복원추출(sampling with replacement)을 기술하는 이항분포를 사용하여 표본크기를 계산하여 사찰방법들에 할당한다. 본 연구에서는 이항근사법이 사용되는 IAEA의 표본크기 할당계산결과와 이항근사법 대신 초기하분포를 적용한 IAEA표본크기 할당계산결과를 비교 검토하였다.