• Survey Research
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• v.11 no.2
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• pp.1-28
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• 2010

This paper reports the results of the 2009 Internet volunteer panel version of the social survey conducted by Statistics Korea (Korea National Statistical Office). Authors identify socio-psychological characteristics of Internet survey volunteers and present quantitative evaluation of the propensity adjustment weighting method intended to remove Internet sample bias. The nine criteria used for propensity adjustment were regions, urban/rural, gender, age, education, consumer satisfaction, views on income distribution, newspaper access and Internet news access. Propensity adjustment weighting based on the logit model and rim weights were applied to the online survey of 2,903 respondents using the face-to-face area sample data of 37,049 respondents as reference. A total of 106 items were used for evaluating the propensity adjustment weighting methods. The results showed that in 80% of survey items the propensity adjustment weighting yielded better estimates compared to simple demographic weighting. This suggests that Internet surveys by volunteer panels are useful for conducting the general social study in Korea. The reference survey data for this study contains several items on social-psychological behaviors and attitudes, is large in size and obtained by probability sampling. Thus it may be utilized in propensity adjustment of other Internet surveys.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1342-1348
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• 2010

Currently available evaluation checklists are developed for specific purposed using different parameters and items determined by different weighting factors. Those items with different weighting are sometimes said that they are based on the engineering judgement and leap of faith and, therefore, there is a limitation to adapt those checklists for slope-stability evaluation in the field. This study reviews factors affecting slope stability, analyze the relationship between those factors and slope failures using artificial neural network, and proposed a slope-stability evaluation model for adequate weighting for the factors.

• 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.10 s.352
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• pp.55-59
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• 2006

In cellular OFDMA(Orthogonal Frequency Division Multiple Access) systems, each subcarrier may suffer from different amount of interferences from neighbor cells. Suppose that it is possible to accurately estimate inter-cell interferences for each subcarrier, the performance can be considerably improved by applying SINR(Signal to Interference and Noise Ratio) weighting. This paper proposes an inter-cell interference estimation method for cellular OFDMA systems. The proposed method extracts amounts of noise and interferencesby eliminating the channel variation effects of pilot symbols caused by frequency offset, timing offset mobile velocity, and delay spread.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.2
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• pp.514-522
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• 2017

Traffic offloading is a promising solution to solve the explosive growth of mobile traffic. One of offloading schemes, in LIPA/SIPTO(Local IP Access and Selected IP Traffic Offload) offloading, we can offload mobile traffic that can satisfy QoS requirement for application. In addition, it is necessary for traffic offloading using social context due to large traffic from SNS. Thus, we propose the LIPA/SIPTO offloading algorithm using social context. We define the application selection probability using social context, the application popularity. Then, we find the optimal offloading weighting factor to maximize the QoS(Quality of Service) of small cell users in term of effective data rate. Finally, we determine the offloading ratio by this application selection probability and optimal offloading weighting factor. By performance analysis, the effective data rate achievement ratio of the proposed algorithm is similar with the conventional one although the total offloading ratio of the proposed algorithm is about 46 percent of the conventional one.

• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.346-353
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• 2008

This paper defines the concept of “protectability” for the performance evaluation of distance relay considering its sensitivity and selectivity. The paper starts from the probabilistic modeling of the errors, and based on this model, a detailed explanation of protectability calculation for each zone of the distance relay is presented. An effect of the Weighting Rate and the Measurement Deviation on the protectability evaluation is also given. By considering this effect, the optimization of relay setting can be realized. The proposed method is applied to a typical model system to show its effectiveness

• Journal of the Korean Society for Library and Information Science
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• v.48 no.3
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• pp.303-334
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• 2014

This study aims to develop standard indicators and methodology for college & university libraries' evaluation based on the agreement among various stake-holders, then suggests a new evaluation system. For the goal, we identify purposes and required conditions, then develop indicators for the evaluation through open-ended interviews, a questionnaire survey, and focus group for reaching an agreement on the included indicators among the stake-holders, finally we construct the overall evaluation structure and weighting system. The overall structure is developed based on process-centered approach, then both the internal and functional viewpoint and external and service-oriented viewpoint are considered. The weighting system is based on the balance among the process categories, such as resources, process, and output elements. Additionally, we suggest methodology for the evaluation and annual improvement process for ongoing improvement of the evaluation system. We expect that the results from this study will contribute not only to the evaluation activities but also to active discussions on library performance and its predictor factors.

• Journal of the Korean Geotechnical Society
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• v.28 no.10
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• pp.89-96
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• 2012

In this study landslide causal factors which are considered to have the same effect in assessment techniques are categorized and their impact on landslides is analyzed to acquire reasonable weighting factors in the landslide hazard. Results are compared to those of the Assessment Chart developed by National Institute for Disaster Prevention (NIDP) and the adequacy and proper portion for landslide causal factors are considered. The Artificial Neural Network (ANN) method applied to 28 landslide areas is incorporated to evaluate the reasonable rating. Results show that the following items in the Chart are necessary to modify their portions in order to implement the precise assessment results: 1) Estimated damage; 2) Tension crack; 3) Existence of valley.

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.205-212
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• 2010

The purpose of this study was to compare the efficiency of visual perception and impulse according to the three types of Taekwondo players to be able to supply an efficient training method, for this a total of 12 representative Taekwondo players of the Korean National team, 4 poomsae players, 4 kyokpa players and 4 kyorugi players weighting between 68 to 74 kg, and the results from the motion analysis system, eye tracker and Electronic hogu are as follows. For the visual perceptual function, the total body reaction time was slowest for the kyokpa group, and for the visible reaction and vision fixation time was longest of the poomsae group, while the performance movement was fastest for the kyorugi group. As for description of the two kicking motions dollyo chagi and dolgae chagi the longer visual fixation helps the accuracy of the kick. In conclusion, as there was a difference between the groups, this information could help to train the visual perception of players according to what event they are participating in.

• Annual Conference on Human and Language Technology
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• 2010.10a
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• pp.31-36
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• 2010

이중 언어 병렬 말뭉치를 이용하는 패러프레이즈 추출 과정에서는 일반적으로 다른 언어를 피봇 언어로 하여 단어 및 구 정렬 과정을 두 번 거친다. 따라서 단어 정렬의 오류 전파 문제가 큰 단점이 된다. 특히 한국어와 영어와 같이 언어의 구조적인 차이가 큰 경우, 단어 정렬 오류가 더 많고 이로 인해 잘못된 피봇 프레이즈가 선정되는 문제가 더욱 심각하다. 이런 문제를 보완하기 위해, 본 논문에서는 패러프레이즈 추출 과정에서 피봇 프레이즈를 차별화하는 방안으로서, 올바른 피봇 프레이즈에 더 높은 가중치를 부여 하는 방법을 제안한다. 실험 결과, 기존의 패러프레이즈 추출 방법에 제안하는 피봇 가중치 부여 방법을 추가적으로 적용했을 때, 패러프레이즈 추출 정확률과 재현율이 모두 향상됨을 확인할 수 있었다.