• The Korean Journal of Applied Statistics
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• v.22 no.2
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• pp.375-385
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• 2009

For 2007 Korea presidential election, most polls by telephone surveys indicated Lee Myung-Bak led the second runner-up Jung Dong-Young by certain margin. The margin between two candidates can be estimated accurately by averaging individual poll results, provided there exists no systematic bias in telephone surveys. Most Korean telephone surveys via telephone directory are based on quota samples, with the region, the gender and the age-band as quota variables. Thus the surveys may result in certain systematic bias due to unbalanced factors inherent in quota sampling. The aim of this study is to answer the following questions by the analytic methods adopted in Huh et al. (2004): Question 1. Wasn't there systematic bias in estimates of support rates. Question 2. If yes, what was the source of the bias? To answer the questions, we collected eighteen surveys administered during the election campaign period and applied the iterated proportional weighting (the rim weighting) to the last eleven surveys to obtain the balance in five factors - region, gender, age, occupation and education level. We found that the support rate of Lee Myung-Bak was over-estimated consistently by 1.4%P and that of Jung Dong-Young was underestimated by 0.6%P, resulting in the over-estimation of the margin by 2.0%P. By investigating the Lee Myung-Bak bias with logistic regression models, we conclude that it originated from the under-representation of less educated class and/or the over-representation of house wives in telephone samples.

• Survey Research
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• v.6 no.2
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• pp.51-74
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• 2005

The internet survey methods have been more and more widely used as the coverage of the fixed-line telephone is being reduced due to the diffusion of mobile phone. So, there is a need to know the accuracy of this new survey method. This study aims to estimate the accuracy of the internet survey method and identify the factors affecting the accuracy of this method, For this purpose, we analyzed the election poll data during the 17th general election period. These data include fixed-line telephone survey data, internet survey data, mobile phone survey data and the election voting data. The analysis shows that the prediction errors of the internet survey were a little more than those of the telephone or mobile phone survey. But the differences are not significant. It follows from this result that we can use the internet survey method in social survey context. This study also found that the respondent's willingness to participate in the survey, the probability of being at home during survey and the respondent's educational level were affecting the accuracy of the internet survey. Further studies to develop weighting method with these factors are needed.

• Survey Research
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• v.13 no.1
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• pp.113-134
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• 2012

It is very vital for the presidential preference not only to be a political achievement of the president himself, but also to be an influential base of people-related policy and its implementation. The purpose of this study is to provide the newly developing ideas to compose an appropriate question and to point out the present problems in the utilization of survey results. At first, it turned out to be inappropriate to make a question for evaluation of presidential job approval in the perspective of questionnaire planning. As the respondents were not informed of what the president did, so they were more likely not to know whether the president did well or not. Secondly, the correlation analysis has been made between the evaluation question of the presidential job approval and policy-related questions including the direct one for the presidential preference in the aspect of statistical analysis. Through this process, evaluation of the presidential job approval is not accountable and the direct question for the presidential preference is at best explainable. In conclusion, it seems more persuasive to compare the statistical outcome of the presidential preference which has been derived of to the high rating what the respondents think comprehensively not depending on a subjective decision by mass media.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.5
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• pp.699-704
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• 2006

Twenty-four cannulated Small-tailed Han${\times}$Poll Dorset wethers (BW $47.5{\pm}2.1kg$) were used to determine the effects of forage to concentrate ratio (40:60 vs. 70:30), monensin supplementation (0, 15 or 30 ppm, DM basis) and interactions of these two factors on cis-9, trans-11 conjugated linoleic acid (cis-9, trans-11 CLA) and trans-11 octadecenoic acid (trans11-$C_{18:1}$) concentrations in ruminal contents and plasma in sheep. The experiment was designed as a $2{\times}3$ factorial. The diet contained Chinese wild rye grass hay (Aneurolepidium Chinese), cracked corn, soybean meal, NaCl, limestone and trace mineral premix. Dietary crude fat and linoleic acid ($C_{18:2n-6}$) were adjusted with soybean oil to about 7.0% and 24.0 mg/g (DM basis), respectively. High forage diets increased (p<0.001) the concentrations of trans11-$C_{18:1}$ and cis-9, trans-11 CLA in ruminal contents and plasma. Monensin supplementation increased (p<0.001) the concentration of trans11-$C_{18:1}$ in ruminal contents, but had no effect on that of cis-9, trans-11 CLA. Concentrations of trans11-$C_{18:1}$ (p<0.019) and cis-9, trans-11 CLA (p<0.022) in plasma increased with dietary monensin levels. Interactions of forage: concentrate ratio and monensin level tended to affect the concentrations of trans11-$C_{18:1}$ (p<0.091) and $C_{18:2n-6}$ (p<0.083) in ruminal contents. Increasing forage levels increased the concentrations of trans11-$C_{18:1}$ and cis-9, trans-11 CLA in the rumen. Supplementing with monensin increased the ruminal production of trans11-$C_{18:1}$ and concentrations of trans11-$C_{18:1}$ and cis-9, trans-11 CLA in plasma.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.158-165
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• 2017

The purpose of this study is to provide basic data for increased understanding of detailed customer needs by age group, and also to improve customer satisfaction. The survey was conducted from August $30^{th}$ to September $15^{th}$, 2017. The poll was conducted with 302 persons aged from 20's to 50's by using convenience-sampling method and self-administration method for survey. The results were analyzed by frequencies, independent sample t-test, Pearson correlations, and through multiple regression analysis. The study results are briefly summarized as follows. First, the overall age group's interest of hand's health was robustly high. Second, in the 20s and 30s age groups hand care interest and self-hand care (r=.284, p<.01) increased with improved hand health condition. In the 40s and 50s age groups there were positive correlations between hand health condition and Information recognition(${\beta}=.246$, p<.1), Product use(${\beta}=.312$, p<.05), and Professional Hand Care(${\beta}=.354$, p<.000). This study indicates that hand care concern and management behaviors change with age. Therefore, further research and more specific follow-up are required for improvement of the awareness of healthy hands.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.400-409
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• 2016

The geospatial information industry has the advantage of being able to converge with other industries to create new value. Therefore, efforts are underway to promote the growth of this dwindling national industry by endorsing policies and initiatives to promote its convergence with other industries. In this study, feedback was collected from experts in various fields through three rounds of polls using the Delphi method. The poll results were used to investigate the causes of hindrance to the growth of the geospatial information industry and to build a comprehensive solution to this problem. As a result, 27 strategies were constructed based on the users' requirements related to policy, data and service, including the demands for establishing public polling methods, enhancing data quality and advertisement. Since the coefficient of variance fell between 0.11 and 0.20 in the importance evaluation, an amicable consensus was reached between the experts. Considering that the convergence of industries is achieved through the integration of various types of technology and information, it is important to consider the requirements of users in different industries. In this respect, the results of this study will serve as a useful base for constructing mid-to-long term road maps to promote the development of the geospatial information industry.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.587-598
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• 2016

In predicting an outcome of election using a variety of methods ahead of the election, non-response is one of the major issues. Therefore, to address the non-response issue, a variety of methods of non-response imputation may be employed, but the result of forecasting tend to vary according to methods. In this study, in order to improve electoral forecasts, we studied a model based method of non-response imputation attempting to apply the Monte Carlo Expectation Maximization (MCEM) algorithm, introduced by Wei and Tanner (1990). The MCEM algorithm using maximum likelihood estimates (MLEs) is applied to solve the boundary solution problem under the non-ignorable non-response mechanism. We performed the simulation studies to compare estimation performance among MCEM, maximum likelihood estimation, and Bayesian estimation method. The results of simulation studies showed that MCEM method can be a reasonable candidate for non-response model estimation. We also applied MCEM method to the Korean presidential election exit poll data of 2012 and investigated prediction performance using modified within precinct error (MWPE) criterion (Bautista et al., 2007).

• Journal of Digital Convergence
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• v.12 no.2
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• pp.373-378
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• 2014

To investigate the wear status of contact lenses by analyzing care of contact lenses container and actual condition of people wearing contact lenses and in Gyeonggido. The results were based on a questionnaire survey of 200 people who are the students of the middle school, the high school and the college among the clients of opticians to purchase contact lenses for six months from January 2013 to July 2013. According to the poll, the highest number of those polled, 139 (55.16%) people, said they were wearing cosmetic color contact lenses. Female respondents and male respondents were in the proportion of 177 (88.5%) to 23 (11.5%), respectively. 37 people (18.5%) who responded said "yes" to the question of them sharing contact lenses and glasses. 103 people (51.5%) answered "no" to the question of regularly replacing their lens containers. 148 people (74%) answered "yes" to the question of having glasses in order to investigate contact lens wearers user rate of glasses. The highest number of respondents, 127 people (63.5%), said "middle school" was the first time that they wore contacts. Meanwhile, 65 people (43.92%) said they initiated wearing glasses at 4th-6th grades. It is considered that it is necessary using proper contact lenses suitable for the clients' eye health in order of vision correction, rather than for cosmetic purposes. The role of the optician is considered to be very important for the proper management of the appropriate contact lens hygiene and regular optical check-ups of the contact lens wearers.

• The Journal of the Korea Contents Association
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• v.11 no.3
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• pp.477-486
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• 2011

In this paper, I had tried to analyze the relationship between the time assigned for computer usage and weakening eyesight. First of all, students classified by gender, school year, eyesight, and wearing glasses along demographic characters took part in a poll, and The questionnaire included questions about computer time, factors of weakening eyesight, and purpose of computer use. The finding in this analysis composed of a cross-tabulations between annual eyesight change and the factors to change their eyesight is that 63.6 % of 165 students participated in this survey weakened their eyesight within a year. To show a correlation between computer usage duration and worsening eyesight in this paper, regression analysis indicated weakened vision by computer usage duration per day and week instead of a year. In addition, according to the analysis between computer usage duration and weakened vision for the people who wear glasses or not trough Independent-Samples T test, weakened vision was shown in computer usage duration per day and week, but not shown in the duration by the year. Therefore, weakening vision was also worse for the people who didn't wear glasses than the others. This study indicated 24..5% of teenagers had poor eyesight by using their computer. According to the frequency analysis on purposes of computer usage, the biggest purpose accounting for 36.4% of the total was the computer usage as a game consol, and the computer as a learning tool was the next biggest purpose at 32.1%. This paper showed the correlation between computer usage time and a factor of weakened eyesight through an analysis of the factor. Therefore, schoolchildren's parents should be more interested in their computer usage.

• Survey Research
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• v.12 no.1
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• pp.153-174
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• 2011

This research aims to discuss the causes of inaccuracy in public opinion polls currently conducted in Korea. In particular, identifying the problems in sampling frame and sampling methods in political and social public opinion polls is an important question. Currently, most polling organizations operating in Korea are using phone number directories provided by Korea Telecom(KT) as its sampling frame for conducting most political polls. A critical problem of using a phone number directory as a sampling frame is that unlisted phone numbers can never be included in the sample. If a systematic difference in socio-demographic or politico-economic characteristics exists between the listed number using group and the unlisted group, using a phone number directory as a sampling frame cannot produce a sample that can represent the whole adult population in Korea. According to the poll result commissioned by the Asan Institute for Policy Studies in January 2011, there are statistically significant differences in socio-demographic and politico-economic characteristics between those two groups, and those differences led to the differences in the presidential job approval rating and party support. Our findings include that the listed number using group is more pro-Grand National Party and show stronger support for the president than the unlisted group.