• 한국인구학
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• 제11권2호
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• pp.11-21
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• 1988

• 대한가정학회지
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• 제44권8호
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• pp.79-87
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• 2006

The purpose of this study was to estimate the minimum monthly food cost for the low income population. The food consumption data of 9,311 individuals from the 2001 Korean National Health and Nutrition Survey was used. The monthly food cost was calculated using the Consumer Food Price Database for the year 2001 provided by the Public Health Nutrition Laboratory, Seoul National University. The low income population (n = 1,310) was characterized as older age, lower income, smaller family size, lower education level, and lower energy intake as compared with the total population (n = 8,001). The estimated food cost showed that men in the low income population needed 15% more money for purchasing food to maintain the energy intake level at the average energy intake level of men in the total population. It was also estimated that women in the low income population needed 9% more money for purchasing food to maintain the energy intake level at the average energy intake level of women in the total population. There were differences in monthly food costs depending on the sex and age, and family size. The results of this study could be used as basic information to establish minimum food cost for the low income population in Korea.

• 한국수산과학회지
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• 제50권5호
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• pp.594-604
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• 2017

The Korean National Institute of Fisheries Science (NIFS) has biannually (spring and fall, respectively) deployed a bottom trawl survey along the coastal areas for last decade, taking samples on a regular basis (i.e., a systematic sampling). Despite the availability of the survey data, NIFS has not yet officially reported the estimates of the groundfish population sizes as well as has not evaluated uncertainty of the estimates. The objectives of our study were to infer the relative size of a fish population, applying two different sampling techniques (namely simple and stratified sampling) with different observation units to the NIFS survey data, and to compare those two techniques in bias and precision. For demonstration purposes, we used data on Pacific cod (Gadus macrocephalus) collected by the 2011-2015 surveys, and the results of simple and stratified sampling showed that the point estimates and precision varied by observation unit as well as the sampling technique.

• Asian Pacific Journal of Cancer Prevention
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• 제16권11호
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• pp.4677-4683
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• 2015

When there is no sampling frame within a certain group or the group is concerned that making its population public would bring social stigma, we say the population is hidden. It is difficult to approach this kind of population survey-methodologically because the response rate is low and its members are not quite honest with their responses when probability sampling is used. The only alternative known to address the problems caused by previous methods such as snowball sampling is respondent-driven sampling (RDS), which was developed by Heckathorn and his colleagues. RDS is based on a Markov chain, and uses the social network information of the respondent. This characteristic allows for probability sampling when we survey a hidden population. We verified through computer simulation whether RDS can be used on a hidden population of cancer survivors. According to the simulation results of this thesis, the chain-referral sampling of RDS tends to minimize as the sample gets bigger, and it becomes stabilized as the wave progresses. Therefore, it shows that the final sample information can be completely independent from the initial seeds if a certain level of sample size is secured even if the initial seeds were selected through convenient sampling. Thus, RDS can be considered as an alternative which can improve upon both key informant sampling and ethnographic surveys, and it needs to be utilized for various cases domestically as well.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• 제4권1호
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• pp.1-8
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• 2023

In this study, we aimed to quantify the population size and spatial distribution of three predatory Scarites species in coastal sand dunes. In June and August 2014, 252 pitfall traps were utilized to conduct a trapping web analysis at three distinct sites with varying vegetation dominance values. Scarites sulcatus had the largest estimated population in a 10 m² area with a habitat density of 36.6 in a Vitex rotundifolia community area (site B) in the June survey. In contrast, Scarites aterrimus had the largest population size with a habitat density of 2.9 in a Calystegia soldanella community area (site A) in the August survey. Spatial distribution analysis revealed that S. sulcatus dominated the Vitex rotundifolia community without preference for a particular site, whereas S. aterrimus and Scarites terricola pacificus were primarily observed on the beach. The results indicated that the three Scarites species in the Sohwang coastal sand dune region exhibited differences in their spatial and temporal distributions in the coastal dune ecosystem in order to avoid competition and predation. In conclusion, our findings can be utilized to estimate the population density of the genus Scarites on the Korean Peninsula. The outcomes of this study will contribute to estimating insect population densities on the Korean Peninsula and developing investigative assessment methodologies.

• Journal of the Korean Statistical Society
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• 제8권1호
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• pp.3-14
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• 1979

When we estimate the population proportion of the individuals in the population for the attribute or the characteristic, we consider the sample survey. We can consider many methods of the sample survey, as mail questionnaire, visits, personal calls, etc. When we have the list of units in the population, we usually make use of the mail questionnaire. It is economical and free from the investigator's effect on the respondent, but it has some objections. The principal objection is that it involves a large nonresponse rate that might cause a singificant bias in the result. The bias arises from the different in the characteristics under investigation between those who respond and those who do not respond.

• Communications for Statistical Applications and Methods
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• 제20권5호
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• pp.367-376
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• 2013

Cut-off sampling is widely used for a highly skewed population like a business survey by discarding a part of the population (the take-nothing stratum). In this paper, we suggest a new composite estimator of the take-nothing stratum total obtained by use of the survey results of the take-nothing stratum and a take-some sub-stratum (a part of take-some stratum) for a more accurate estimate of the population total. Small simulation studies are conducted to compare the performances of known estimators and the new composite estimator suggested in this study. In addition, we use briquette consumption survey data for real data analysis.

• Journal of the Korean Data and Information Science Society
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• 제15권1호
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• pp.1-10
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• 2004

In the Korean Economically Active Population Survey(EAPS), the sample sizes for small areas are typically too small to provide reliable estimators because the EAPS has been designed to produce unemployment statistics for large areas such as Metropolitan Cities and Province. In this study, we consider the synthetic and composite estimators for the unemployment rate of small areas, and apply them to real data on Choongbook province which is from the Korean EAPS of December 2000. The mean square errors of these estimators were estimated by the Jackknife method, and the efficiencies of small area estimators were evaluated in terms of the relative standard errors and the relative root mean square errors. As a result, the composite estimator is much more efficient than other estimators and it turns out that the composite estimator can produce the reliable estimates of the unemployment rate of small areas under the current EAPS system.

• 한국환경과학회지
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• 제22권12호
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• pp.1589-1598
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• 2013

The objective of this study was to evaluate associations between airborne manganese and blood manganese in a general population of South Korean adults. The concentrations of airborne manganese in total suspended particulate (TSP) were calculated from data obtained from ambient air-monitoring stations (AAMSs) located in South Korea. Blood manganese data obtained Korean National Health and Nutrition Examination Survey (KNHANES) using a rolling sampling design involving a complex, stratified, multistage, probability cluster survey of a representative sample of the non-institutionalized civilian population of South Korea. Airborne manganese geometric means was 46.10 $ng/m^3$, blood manganese geometric means were 1.19 ${\mu}g/d{\ell}$ for male and 1.40 ${\mu}g/d{\ell}$ for female. In multiple linear regression analysis of log transformed blood manganeseas a continuous variable on airborne manganese, after adjusting for covariates including gender, age, job, smoking and drinking status, education level, BMI (body mass index). Airborne manganese was positively associated with blood manganese with statistical significance. The present study confirms that airborne manganese is a possible contributor to the increase of blood manganese in the adult general population.

• Journal of Korean Neurosurgical Society
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• 제46권5호
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• pp.443-450
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• 2009

Objective : We estimated the number of Korean adults with back pain and evaluated population-based associated factors of back pain from a representative sample data from the Fourth Korea National Health and Nutrition Examination Survey. Methods : The number of Korean adults who experienced back pain (experienced patients), those who experienced back pain lasting for three or more months during the past year (chronic patients), and those who were currently suffering from back pain (current patients) were estimated by analyzing the data from the fourth Korea National Health and Nutrition Examination Survey conducted in 2007 using surveyfreq procedure of the SAS statistical package. Population-based odds ratios for being experienced, chronic, and current patient according to demographic (age and gender), socioeconomic (education and occupation), and lifestyle factors (smoking, drinking, and exercise) were estimated using surveylogistic procedure. Results : It was estimated that there were 5,554,256 (proportion, 15.4%; 95% CI, 4,809,466 - 6,299,046) experienced patients, 2,060,829 (5.7%; 1,557,413-2,564,246) chronic patients, and 3,084,188 (8.5%; 2,600,197 - 3,568,179) current patients among 36,107,225 Korean adults aged 20-89 years in 2007. Each of explanatory variables was significantly associated with at least one of the response variables for back pain. Conclusion : Based on our study results, further efforts to investigate epidemiology of back pain, to evaluate associated factors, and to improve treatment outcomes are needed.