• Proceedings of the Korean Association for Survey Research Conference
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• 2006.12a
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• pp.67-83
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• 2006

In successive sampling on two occasions the problem of estimating a finite population quantile has been considered. The theory developed aims at providing the optimum estimates by combining (i) three double sampling estimators viz. ratio-type, product-type and regression-type, from the matched portion of the sample and (ii) a simple quantile based on a random sample from the unmatched portion of the sample on the second occasion. The approximate variance formulae of the suggested estimators have been obtained. Optimal matching fraction is discussed. A simulation study is carried out in order to compare the three estimators and direct estimator. It is found that the performance of the regression-type estimator is the best among all the estimators discussed here.

• Survey Research
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• v.2 no.2
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• pp.153-165
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• 2001

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.

• Proceedings of the Korean Association for Survey Research Conference
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• 2001.11a
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• pp.77-85
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• 2001

In this paper we study the calibration estimator and its variance estimator for the population total using a bootstrap method according to the levels of an auxiliary information having strong correlation with an interested variable in nonresponse situation. At this point, we find tire calibration estimator in case of auxiliary information for population and sample, and then we drive the bootstrap variance estimator of it. By simulation study we compare the efficiencies with the Taylor and Jackknife variance estimators.

• Communications for Statistical Applications and Methods
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• v.9 no.2
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• pp.565-576
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• 2002

We propose a new sampling design for the 2001 Health Index Survey at Seoul. In this stratified two-stage sampling design, the ED(enumeration district) of 2000 Population and Housing Census is used as primary sampling unit and the Gu is used as stratification variable in order to obtain the sub-domain estimate for 25 Gu's as well as population estimate for Seoul. The sample ED's are systematically selected after the Ed's are ordered by location and property to obtain a representative sample. And also, the imputation methods for item nonresponses are suggested.

• Journal of the Korean Data and Information Science Society
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• v.12 no.2
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• pp.47-55
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• 2001

Usually estimating the means is used for statistical inference. However depending the purpose of survey, sometimes totals will give the better and more meaningful in statistical inference than the means. Here in this study, we dealt with the unemployment population of small areas with using 4 different small area estimation methods: Direct, Synthetic, Composite, Bayes estimation. For all the estimates considered in this study, the average of absolute bias and men square error were obtained in the Monte Carlo Study which was simulated using data from 1998 Economic Active Population Survey in Korea.

• Phonetics and Speech Sciences
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• v.3 no.1
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• pp.111-116
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• 2011

The purpose of this study was to analyze the association between self-reported voice problems and voice disorders in the Korean adult population. Data were collected from the 4th Korea National Health and Nutritional Examination Survey (2008) from 3,135 subjects (1,310 men and 1,825 women) aged 19 years and older. Multi-nominal logistic regression analyses were used to examine the association between self-reported voice problems and voice disorders in the Korean adult population. Adjusting for covariates (age, sex, education level, job, smoking, alcohol drinking, thyroid disorders, pain and discomfort during the last 2 weeks), self-reported voice problems included independently associated functional voice disorders (OR=4.70, 95% CI: 3.14-7.03) and organic voice disorders (OR=3.89, 95% CI: 1.57-9.65). The results of the present study verified that self-reported voice problems are valuable indicators for voice disorders. Further research is needed to ascertain the effect of self-reported voice problems on voice disorder in adults.

• Journal of KIBIM
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• v.10 no.1
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• pp.23-29
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• 2020

The vacant houses commonly observed in urban aging are considered to be representative signs of urban decline. Vacant houses are themselves vulnerable to security, and in particular, they are exposed to disasters due to poor management, which can accelerate the decline of the area. This study is to classify the area and analyze the causes and characteristics of the occurrence of vacant houses by type based on the data through the survey on the vacant houses in Incheon. This research analyze vacant house data survey so to characterized and categorized types of vacant houses. The criteria of vacant houses analysis are population density, population growth, aging extent. In conclusion there are four types of region in Incheon area according to housing types, hazard classes, building age and building areas. Type A is inner city, type B is mixed, type C is expandable and type D is unsular types.

• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.365-372
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• 2018

The Wintering Waterbird Census of Korea was started in 1999 and monitors 200 major migratory sites in South Korea. Waterfowl counts have been undertaken for more than 20 years since; however, a limited number of studies have analyzed the temporal patterns of waterfowl population. In this study, we analyzed population size changes of wintering whooper swan (Cygnus cygnus) at 112 monitoring sites from 2001 to 2018. The average number of whooper swans was $4,296{\pm}42.66$ and there was a trend for an increase in population size across the survey period. We found that the population in the Nakdong River Estuary, one of the major wintering sites over 18 years (26.22% of the national population), had rapidly decreased (-0.77% per year). Conversely, the whooper swan population in the Junam Reservoir and Sihwa Lake increased (+1.64%, +0.54% per year, respectively). Estuaries showed the highest dominance of whooper swans among the five different habitat types, accounting for 32.13% of the population. Reservoir/lakes had 30.60% of the total population and reclaimed lakes(18.24%), river (13.11%), and coast (5.93%) followed. The annual distribution of the whooper swan population in South Korea has been affected by various habitat conditions resulting from human activities and urbanization. To better understand the complex factors that can cause rapid changes in wintering waterfowl populations, it is necessary to integrate the data from the bird census program with environmental conditions to conduct in-depth pattern analyses over longer time periods.

• Journal of Korean Society for Quality Management
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• v.47 no.4
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• pp.847-859
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• 2019

Purpose: The companies must be located in the area, scale up, create jobs, and return to the local economy. This paper attempted to analyze empirically the relationship between regional context and entrepreneurial orientation(EO) in the region of Korea. Methods: This paper analyzed survey data and regional statistics. We measured EO by region and then examined which regional context affect EO. Regional contexts were measured by population, economic size, budget size, firm size, innovation capacity, and education level. EO was measured by innovativeness, risk taking, proactiveness, autonomy, competitive aggressiveness, and need for achievement. Results: EO was high in the region where the budget size per thousand population, the number of manufacturers per thousand population, the number of new corporations per thousand population, the number of R&D personnel per thousand population, and the number of students of higher education institutions per thousand population were high. Conclusion: The implications of this paper are that regional context affect EO, and there are differences in budget scale, firm size, innovation capacity, and education level. In regions with many investment resources for innovation and startups and manufacturers, the number of R&D personnel and students of higher education institutions (future R&D personnel), in particular, determines EO.

• Journal of the Korean housing association
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• v.25 no.3
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• pp.123-130
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• 2014

The decrease in the birth rate of the modern changes in population structure changed recovery households and household members. This change was seen in the furniture sector, 2010 population housing total survey data according to the types of households and household members indicate that future changes. Problems can predict the various issues raised, and to ensure that the supply of housing of the population structure and household type is not done properly and home sales take a look at home since 2000, was popular during the 2010 State. Therefore, this study is suggesting workarounds necessary adjustments due to changes in population structure, analyze news coverage of members of households with housing demand and housing as a base quantity change in the future of furniture and home situation changes, including housing demand and supply to purpose. Specify the range of Daegu-City research studies range, national statistical data and related literature, comparative analysis of time trends and derive a conclusion.