• Proceedings of the Korean Association for Survey Research Conference
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• 2000.06a
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• pp.57-73
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• 2000

Small area estimation is becoming important in survey sampling due to a growing demand for reliable small area statistics. In estimating means, totals, and other parameters for small areas of a finite population, samplie sizes for small areas are typically small because the overall sample size is usually determined to provide specific accuracy at a much higher level of aggregation than that of small area. The usual direct estimators that use the only information which is gotten from the sample in a given small area provide unreliable estimates. However, indirect estimators utilize the information from the areas related with a given small area, that is borrow strength from other related areas, and so give more accurate estimates than direct estimators. In this paper we investigate small area estimation methods such as synthetic, composite and empirical best linear unbiased prediction estimator, and apply them to real domestic data which is from the Survey of Hotels and Restaurants in In-Chon as of 1996 and then evaluate the performance of these methods by measuring average squared errors. This evaluation shows that indirect estimators, which are small area estimation methods, are more efficient direct estimator.

• The Korean Journal of Applied Statistics
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• v.33 no.1
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• pp.11-23
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• 2020

Sampling design should provide statistics to meet a given accuracy while saving cost and time. However, a large number of non-responses are occurring due to the deterioration of survey circumstances, which significantly reduces the accuracy of the survey results. Non-responses occur for a variety of reasons. Chung and Shin (2017, 2019) and Min and Shin (2018) found that the accuracy of estimation is improved by removing the bias caused by non-response when the response rate is an exponential or linear function of variable of interests. For that case they assumed that the error of the super population model follows normal distribution. In this study, we proposed a non-response bias adjusted estimator in the case where the error of a super population model follows the gamma distribution or the log-normal distribution in a business survey. We confirmed the superiority of the proposed estimator through simulation studies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.749-756
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• 2003

Hydroacoustic and open-closing zooplankton net survey were conducted to understand the characteristics of the sound scattering layer (SSL) and to estimate the density of an euphausiid (Euphausia pacifica) in the SSL, in the northwestern part of the East China Sea. The survey was carried out during July 6-9 2002 at 8 sampling stations for zooplankton. The virtual echogram technique was used to identify E. pacifica from all acoustic scatters. Mean volume backscattering strength difference $(MVBS_{120kHz-38kHz})$ and target strength equation for E. pacifica were derived from the Distorted-wave Born Approximation (DWBA) model. Although vertical migration of the SSL is similar to the general pattern, dispersion at night shows some differences. Estimated mean density using acoustic data ranged from $20.4-221.4\;mg/m^3$ over the whole depth, and $87.1-553.5\;mg/m^3$ in the SSL. The density using the zooplankton net ranged from $0.2-362.4\;mg/m^3$ and was not related to net deploying method. The results from the acoustic and net survey suggest that E. pacifica might be an important zooplankton community in the northwestern part of the East China Sea.

• Journal of Dental Anesthesia and Pain Medicine
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• v.15 no.2
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• pp.85-92
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• 2015

Background: Many people experience varying levels of discomfort when confronted with the prospect of dental treatment. Dental treatment can be a traumatic experience, especially for children and adolescents with dental anxiety. In this age group, dental fear causes a significant problem in dental management and has been related to severe dental caries and dental pain. The Dental Fear Survey (DFS) is the most widely used measure of dental fear. This study was undertaken to develop the Korean version of the DFS (K-DFS) and test its reliability and validity. Methods: The K-DFS, which uses projective techniques to measure children's and adolescents' dental fear, was developed. The DFS was translated into Korean and participants were selected via convenience sampling. Reliability and validity were tested using data from a sample of 813 middle school students in Gyeonggi Province, selected from the Self questionnaire survey. The K-DFS was administered twice to 102 adolescents aged 12-15 years. Results: The K-DFS had high internal consistency reliability (99.1%) but low test-retest reliability. Conclusions: The results indicate that the Korean versions of the DFS have good internal consistency reliabilities and test-retest validities. However, we need to further examine the test-retest reliability of the K-DFS and replicate the current study in different samples covering various age groups.

• Parasites, Hosts and Diseases
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• v.54 no.5
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• pp.685-691
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• 2016

Chewing lice (Phthiraptera) that parasitize the globally threatened swan goose Anser cygnoides have been long recognized since the early 19th century, but those records were probably biased towards sampling of captive or domestic geese due to the small population size and limited distribution of its wild hosts. To better understand the lice species parasitizing swan geese that are endemic to East Asia, we collected chewing lice from 14 wild geese caught at 3 lakes in northeastern Mongolia. The lice were morphologically identified as 16 Trinoton anserinum (Fabricius, 1805), 11 Ornithobius domesticus Arnold, 2005, and 1 Anaticola anseris (Linnaeus, 1758). These species are known from other geese and swans, but all of them were new to the swan goose. This result also indicates no overlap in lice species between older records and our findings from wild birds. Thus, ectoparasites collected from domestic or captive animals may provide biased information on the occurrence, prevalence, host selection, and host-ectoparasite interactions from those on wild hosts.

• Journal of Korean society of Dental Hygiene
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• v.19 no.1
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• pp.117-129
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• 2019

Objectives: The purpose of this study was to investigate the influence of demographic characteristics and oral health status on unmet dental needs among preschool children and to provide a basis for improvement of the dental care equality and accessibility using data from the $6^{th}$ National Health and Nutrition Survey. Methods: This study was performed using data collected from the $6^{th}$ National Health and Nutrition Survey. The subjects were 1,472 out of 22,940 people, who participated in the survey and under went oral examination. IBM SPSS Statistics (Version 20.0) was used for statistical analyses based on the complex sampling design. Frequency analysis was performed to determine the distribution of unmet dental needs according to the characteristics of the subjects. The Rao-Scott ${\chi}^2$ test was performed to examine the relationship of unmet dental needs with general characteristics and health- and oral health-related variables. Relevant factors were determined using binary logistic regression analysis. Results: The factors that had statistically significant relations with unmet dental needs included age, medical insurance, household income, limited physical activity, history of dental caries in deciduous teeth, and subjective health status. Logistic regression analysis of complex samples was conducted to determine factors related to unmet dental needs. The results of analysis showed that limited physical activity and history of dental caries in deciduous teeth were related to unmet dental needs. Conclusions: The results show the factors affecting, and the reasons for, the unmet dental needs of preschool children. Future studies are needed to develop national projects and oral health education reforms to address inequalities in preschool children's dental care.

• Journal of the Korean School Mathematics Society
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• v.25 no.1
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• pp.1-17
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• 2022

The goal of this study was to analyze students' views about statistical themes in Mongolian secondary schools in Ulaanbaatar. To this end, 129 9th grade students were stratified random sampling at two secondary schools in Ulaanbaatar, Mongolia, and a survey was conducted on them. The attitude survey focused on six factors contributing to the attitude: affective, cognitive competency, value, difficulty, interest, and student effort. The results show that students believed their statistical knowledge and skills have increased compared to the beginning of the courses. Furthermore, the survey revealed that they perceived statistics as neither an easy nor a difficult subject. Students' interest in statistics was neutral in general. These results suggest a need to develop effective and innovative statistical teaching and learning methods that can attract attention to statistical topics.

• Journal of Forest and Environmental Science
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• v.38 no.3
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• pp.195-206
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• 2022

Gaining an understanding of bird communities in different habitat types is essential for the conservation of ecologically important habitats. Wetlands possess different types of habitats and provide an important environment for wintering waterbird communities. This study compares avian communities in five different habitat types in the Moeyungyi Wetland Wildlife Sanctuary (MWWS), Myanmar. From December 2014 to the first week of February in 2015, bird and habitat data were collected from representative areas of five habitat types (i.e., short grassland, tall grassland, lotus fields, open water areas, and rice fields) at MWWS. We established nine sampling plots in each habitat type, and used the point quadrat method to survey habitats and the point count method to survey birds in the habitats. Simple one-way analysis of variance (ANOVA) and post-hoc tests were used to determine differences between bird communities. We made 95 detections during 19 daily visits to each of the five habitat types. During the survey period, we recorded a total of 10,389 individuals belonging to 52 different bird species, based on 7-min observations at each of the 45 point count stations. Furthermore, we detected significant differences by habitat structure (i.e., vegetation coverage, height, and density; water depth; and plant species diversity) as well as bird communities (i.e., species richness, abundance, and diversity indices). In addition, the detailed analysis of 52 avian species revealed significant differences among 45 species with respect to the mean numbers of observed individuals in the survey habitats. The findings of this study revealed significant differences in the structure and composition of waterbird communities among the five assessed habitat types. Because natural marshes provide preferable habitats for a larger number and greater diversity of birds, relative to rice fields, natural marshes should be prioritized for conservation and restoration in Moeyungyi Wetland Wildlife Sanctuary.

• Korean Journal of Environment and Ecology
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• v.23 no.6
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• pp.585-593
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• 2009

This study is a survey on the general perceptions of the residents and visitors regarding the Nature Restoration Period in Chilsun Valley in Jirisan National park, and it was designed to establish systematic park management plan for the Special Protected Areas in Korean National Parks. This survey was conducted on the residents of five towns including Chuseong-ri, Gwangjum-dong, Uijung-ri, Uitan-ri and Uipyeong-ri, as well as visitors to Chilsun Valley by using convenience sampling. The result showed that those individuals or groups who responded to the survey were all positive about preservatory effect of Nature Restoration Period in the valley; however they also showed major perceptional differences as to the ways in which the nature restoration period managed. They also disagreed among themselves on the assessment of the extent of damage that could be generated due to the restoration, the appropriateness of the Nature Restoration Period as a management policy and maintenance of the policy in the future. The appropriateness as a policy and the extent of damage due to the Nature Restoration Period particularly showed some serious perceptional differences among five resident groups based on the location of their towns. To minimize current conflict and achieve the goal of Nature Restoration Period, the park management authorities need to communicate more actively with the stakeholders of the local community and NGOs, and secure their support and cooperation by accommodating their ideas and opinions to build a strategic partnership.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.337-349
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• 2011

The purpose of this research is to elucidate the analysis on leisure viewpoint of immigrant female of multi-cultural families. This survey research have been performed with 140 of immigrant females who participate to the program of multi-cultural families support center located in Kyungki-do, Taejeon city, Chungnam-do and Chungbuk-do in 2010 by purposive sampling method. The final analysis was obtained from the survey results of total 89 immigrant females and the credibility of this survey represented Cronbach's ${\alpha}$ value above .613. The apparent results were the follows: First, the major leisure time of immigrant females of multi-cultural families on week days as well as weekend represented to be 1~2 hours. Second, the satisfaction on leisure activity of immigrant females was average level. Third, the best preference as leisure activity was travel. Fourth, their husbands were the favor partner for leisure activity of immigrant females. Fifth, the restriction on leisure activity of immigrant females showed some differences based on age, academic background, nationality and residence period. That is, personal restriction of age was below 25 years old, the highest personal and relative restriction of academic background represented in immigrant females below middle school graduator. Furthemore, the structural restriction and personal restriction on nationality showed the highest in the china and phillippine females, relatively. Personal restriction on residence period was mainly represented in immigrant females residing during 2.1~4 years.