• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1217-1225
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• 2015

Survey research, data is commonly collected through a sample design with complex design features that allow the relative efficiency on the precision of an estimator to be measured using the concept of the design effect compared to simple random sampling as a reference design. This concept is most useful when the design effect can be expressed as a function of various design features. We propose a design effect formula suitable under a stratified multistage sampling by generalizing Gabler et al. (1999, 2006)'s approaches for multistage sampling. Its use can either guide improvement in the design efficiency when in design stage or enable the evaluation of the adopted design features afterwards.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4661-4664
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• 2012

Mammographic breast density is a known risk factor for breast cancer. To conduct a survey to estimate the distribution of mammographic breast density in Korean women, appropriate sampling strategies for representative and efficient sampling design were evaluated through simulation. Using the target population from the National Cancer Screening Programme (NCSP) for breast cancer in 2009, we verified the distribution estimate by repeating the simulation 1,000 times using stratified random sampling to investigate the distribution of breast density of 1,340,362 women. According to the simulation results, using a sampling design stratifying the nation into three groups (metropolitan, urban, and rural), with a total sample size of 4,000, we estimated the distribution of breast density in Korean women at a level of 0.01% tolerance. Based on the results of our study, a nationwide survey for estimating the distribution of mammographic breast density among Korean women can be conducted efficiently.

• Journal of Wellbeing Management and Applied Psychology
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• v.3 no.2
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• pp.1-11
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• 2020

Purpose: We explore to find out and analyze the direct influence of Millennial Orientation on Goals Mediated by work engagement and satisfaction. And, interaction cannot be a direct relationship between research variables. Method: The implementation uses the survey method. This research was conducted at PT. East Kalimantan fertilizer operated in Bontang, East Kalimantan. The population in this study were all employees of PT. East Kalimantan fertilizers operated in Bontang, as many as N = 500 people. The sampling technique used is proportional stratified random sampling. Findings: Millennial orientation influences engagement, job satisfaction and intention to leave, direct engagement has a significant effect on job satisfaction and intention to leave, and job satisfaction is directly related to intention to leave. Originality: Alignment between millennial goals in encouraging job satisfaction and employee engagement, so that it can have an impact on the intention to leave employees, especially at PT. Pupuk. Kaltim. Also, direct millennials as decreasing intention to leave.

• Survey Research
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• v.5 no.2
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• pp.3-30
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• 2004

In Korea, bellwether voting places were selected for exit poll based on the past voting results. Sometimes, voting place stratification were used to improve the exit poll performance. The sampled voting places are intended to mirror the general voters of the entire electoral district. But few studies have been done as to which sampling method works better. This study compared the four sampling methods-bellwether voting place sampling method, random sampling method, stratified bellwether sampling method and systematic sampling from ordered voting places method. When we applied the four methods to the 2004 general election data, the systematic sampling from ordered voting places method outperformed the other three sampling method. Also, we found that the additional sampling of voting places over nine contribute little to the accuracy of the estimation.

• Economic and Environmental Geology
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• v.34 no.1
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• pp.89-104
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• 2001

The Chonju and Samchun streams are passing though Chonju city and several contamination sources are located along these streams. The Samchun stream joins the Chonju stream in the Gosapyeong waste disposal site and the Chonju stream finally joins to the Mankyeong River. The objectives of this study are to determine the state and sources of contamination for heavy metals and anions in the Chonju and Samchun streams and to evaluate the effect of these streams on the contamination of the Mankyeong River. In order to select sampling locations, a stratified random sampling method was used. These streams was divided into several parts according to the expected contamination state, and samples were selected randomly from these parts. Generally, the water qualities of these streams were generally below the Drinking Water Level at the time of sampling in various heavy metals and anions. However, the levels of AI, Fe, $NH_{3}-N,Cl^{-}$, Cl- in these streams could be higher during dry season due to continuous inputs from various contamination sources. This study identified several contamination sources for these streams; two waste disposal sites along these streams for Fe, Mn, AI, Zn and $Cl^{-}$, the Chonju Waste Water Treatment Plant for Zn, Mn, $Cl^{-}$, $SO_{4}S$, $NO_{2}N$, and $NH_{3}-N$ and the untreated sewages for AI, Zn, Mn, $Cl^{-}$, $SO_{4}S$, $NH_{3}-N$ and $PO_{4}^{2-}$. This study also revealed that the Chonju stream itself is an important contamination source for Fe, Mn, $Cl^{-}$ and $SO_{4}S$ in the Mankyung River.

• International Journal of Knowledge Content Development & Technology
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• v.10 no.3
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• pp.51-68
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• 2020

The library provides its services to satisfy the user's approach. Naturally, the development of library services may determine by considering the satisfaction of users. It traces users' perceptions regarding subject access highlighting problems in the retrieval of Bengali documents by subject. This study has designed to assess users' attitudes towards the retrievals of Bengali documents in OPAC through subject headings. For a collection of data, a representative sample has drawn from a large and heterogeneous population consisting of users in university libraries of West Bengal using a stratified sampling technique. Subsequently, under each of the universities, users' community was stratified into students, research scholars, and faculty members. Under each stratum, the sample selected on a random basis. The users met personally to collect relevant data, while they came to the library and went on to search OPAC. A structured schedule, prepared for the purpose, was presented before library users and consequently, interviews and interpretations recorded systematically. In this manner, several factors have identified concerning subject searching and retrieval performance for Bengali documents. This study explores the access using subject headings in multilingual information retrieval systems. Moreover, the suitability of subject headings for retrieval of Bengali resources has ascertained from the users' point of view. The findings demand standard principles and rules for the construction of Bengali subject headings to maintain uniformity and consistency.

• Survey Research
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• v.9 no.3
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• pp.71-91
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• 2008

Workplace Panel Survey(WPS) is the representative panel survey of workplace in Korea. WPS was newly sampled in 2005 and is to be used for the subsequent biennial survey. The main survey is divided into a questionnaire for human resources(HR) manager, a questionnaire for labor relations manager and a questionnaire for representatives of unions. The population of WPS 2005 included workplaces across the country with 30 or more employees. The WPS 2005 was composed of 1,905 workplaces including 290 workplaces in the public sector. The sample was selected by the stratified random sampling. Weighting process for the survey data was introduced to compensate for differential sampling and non-response rates. Personal interviews were conducted using the Computer Assisted Personal Interviewing(CAPI) system during visits by interviewers, along with survey via mail and e-mail concerning employment and financial issues. The CPAI system introduced for the WPS 2005 can by used for automatical detection for errors and inconsistencies which may occur during the survey process. The CAPI system played an important part in enhancing the reliability of the survey data.

• Journal of Korean Society of Forest Science
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• v.5 no.1
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• pp.10-15
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• 1966

1) The purpose of this study was to compare the forest survey by ground method with that by aerial photo method. 2) In this study, the forest type map was made by use of the radial line plotter and radial line triangulation method. 3) The difference between the area found by the forest type map above mentioned and that by compass surveying on the ground was none-significant. 4) On aerial photo the stratification was carried out very easily. 5) The following sampling methods were applied : line plot method, representative sampling method and stratified random sampling on the aerial photo. 6) In confirming sampling point the line plot method and the representative sampling method were easier than another. 7) As to stands volume the maximum value was given by stratification, and the minimum by line plot method.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.526-535
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• 2021

Spatial sampling design plays an important role in GIS-based modeling studies because it increases modeling efficiency while reducing the cost of sampling. In the field of agricultural systems, research demand for high-resolution spatial databased modeling to predict and evaluate climate change impacts is growing rapidly. Accordingly, the need and importance of spatial sampling design are increasing. The purpose of this study was to design spatial sampling of paddy fields (11,386 grids with 1 km spatial resolution) in Korea for use in agricultural spatial modeling. A stratified random sampling design was developed and applied in 2030s, 2050s, and 2080s under two RCP scenarios of 4.5 and 8.5. Twenty-five weather and four soil characteristics were used as stratification variables. Stratification and sample allocation were optimized to ensure minimum sample size under given precision constraints for 16 target variables such as crop yield, greenhouse gas emission, and pest distribution. Precision and accuracy of the sampling were evaluated through sampling simulations based on coefficient of variation (CV) and relative bias, respectively. As a result, the paddy field could be optimized in the range of 5 to 21 strata and 46 to 69 samples. Evaluation results showed that target variables were within precision constraints (CV<0.05 except for crop yield) with low bias values (below 3%). These results can contribute to reducing sampling cost and computation time while having high predictive power. It is expected to be widely used as a representative sample grid in various agriculture spatial modeling studies.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.6
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• pp.287-296
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• 2020

The study investigates the relationship and influence between religiosity, reward, and engagement in the public administration sector, both directly and causally via moderation. This study involved one hundred and twenty-three respondents in three local government organizations in Malang City, East Java Province, Indonesia, namely, the Malang City General Hospital, the Population and Civil Registry Office, and the Investment Office. The sampling method uses stratified random sampling from the total population of civil servants in Malang in the three institutions. The data analysis model of this study uses a quantitative approach with a unit of data analysis using the path analysis method. The analytical tools used are smart-PLS and SPSS. The results reveal that the direct combined effect of reward and religiosity has a positive and significant influence on the engagement. However, moderation between reward and commitment, which is bridged by religiosity, does not show positive and significant results. The non-positive relationship shown by testing moderation concludes that there is a separation of purpose between the portion of religiosity in the world of work, where religiosity in this study is only described as part of the concept of worship, and the relationship between the person and his God.