• Annual Conference of KIPS
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• 2009.04a
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• pp.1043-1044
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• 2009

본 논문에서는 GPS 편차 정보를 이용하여 도로 네트워크 지도 제작시 불가피하게 발생하는 오차를 탐지하는 기법을 제안한다. 제안된 기법은 수십에서 수백 킬로미터 범위에 위치한 노드들이 공통적인 GPS오차를 겪는다는 점에 착안하고 있으며 각 도로 네트워크의 차량들이 동시간에 보고하는 위치 좌표를 이용하여 맵 매칭을 수행한 후 해당 시간스탬프의 오차를 계산한다. 이 오차를 이용하여 각 위치 좌표들를 보정한 후 다시 맵 매칭을 수행하여 맵 매칭의 오류가 한계치 이하라면 보고된 위치에 해당하는 도로들은 정확하게 플롯되어 있음을 알 수 있다. 이와 같은 통계들이 오랜 시간동안 쌓인다면 별도의 장비나 통신채널을 사용하지 않고 소프트웨어만으로 도로망 지도의 정확성을 검증할 수 있다.

• Survey Research
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• v.13 no.1
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• pp.1-31
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• 2012

Demographic Analysis(DA) as well as Post Enumeration Survey(PES) are typical methods for evaluating completeness of census and vital statistics. In spite of its popularity, DA has never been attempted in Korea, while other international journals of demography have pointed out the backwardness of death registration in Korea in terms of DA approach. This paper introduces various DA methods and modifies them to be adequate for Korea census and vital statistics. Our method are also applied to reconstruct year-age-sex specific population and estimate their omission rates for year and age. Empirical analysis of census and vital statistics of Korea from 1985 to 2010 demonstrates high completeness of death registration in Korea, contrary to existing literatures. We also investigates abnormal patterns in census by comparing with reconstruction data in view of cohort, sex ratio and age ratio.

• Communications for Statistical Applications and Methods
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• v.15 no.6
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• pp.1013-1026
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• 2008

Kolmogorov-Smirnov(K-S) statistic has been widely used for the model validation of credit rating models. Validation criteria for the K-S statistic is empirically used at the levels of 0.3 or 0.4 which are much larger than the critical values of K-S test statistic. We examine whether these criteria are reasonable and appropriate through the simulations according to various sample sizes, type II error rates, and the ratio of bads among data. The simulation results say that the currently used validation criteria are too lower than values of K-S statistics obtained from any credit rating models in Korea, so that any credit rating models have good discriminatory power. In this work, alternative criteria of K-S statistic are proposed as critical levels under realistic situations of credit rating models.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.3
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• pp.458-471
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• 2013

This paper addresses the limitation of a map comparison metric entitled Figure of Merit through employing a simple land change model. The metric was originally designed to overcome limitations of other existing statistics, such as Kappa, when assessing predictive accuracy of land change models. A series of comparisons between null and predicted outcomes at multiple resolutions as well as a multi-resolution Figure of Merit analysis techniques of validation are compared for spatially segregated calibration and validation datasets. The Figure of Merit at the null resolution in this paper was 57%, although future research must be done to determine if this was simply a coincidence. A Figure of Merit greater than 50% would seem to represent a "Resolution of Merit" in that the Figure of Merit at that resolution becomes greater than the error. Thus, these two metrics should be used in tandem to assess predictive accuracy of a land change model.

• Communications for Statistical Applications and Methods
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• v.19 no.2
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• pp.257-266
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• 2012

R is a free software for statistical analysis that provides simple interfaces to other application programs. Many people are trying to learn R, but it is difficult to learn R compared to commercial software such as SPSS or SAS, and it is cumbersome to provide an environment to teach R. Thus, it is essential to provide a new web-based R environment for novice users or for laboratory use. We developedWebER (a web-based R environment) using PHP on the Linux apache server. WebER can be easily used by any R user because we implemented the same functions as the basic Rgui such as editing R program, generating the text, image outputs, errors and warnings. It is also possible for multi-users to access WebER.

• 재활복지
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• v.21 no.3
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• pp.187-207
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• 2017

The purpose of this study was to explore the characteristics of defining concrete and abstract nouns for the elderly. A total of 382 elderly participated in this study and they were classified into four age groups (i.e., over 55 to under 64, over 65 to under 74, over 75 to under 84, and over 85 year-old group). They performed the word definition task, composed of five concrete and five abstract nouns. The total scores and numbers and ratio of core/supplementary meanings were compared among four elderly groups. The frequency and ratio of error types were also examined. The results showed that all four groups had statistically significant differences in total scores, numbers and ratio of core and supplementary meaning of concrete noun definition task. In addition, abstract noun definition performances revealed group differences except the two groups (over 75 to under 84 and over 85-year-old group). The oldest group showed a sharp increase in error production. The highest ratio of error types were personal experience in over 55 to under 64-year-old group, and over 65 to under 74 year-old groups; and for the target word repetition in over 75 to under 84 year-old group; and no response in over 85 year-old group. In conclusion, both concrete and abstract word defining abilities had age-related deterioration. This decline results from impairment in spreading semantic knowledge within semantic network, which is vulnerable to aging. Characteristics of word definition for elderly can provide basic information to understand various neurolinguistic disorders associated with age.

• Journal of The Korean Association For Science Education
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• v.29 no.2
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• pp.156-167
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• 2009

This study investigated the effects of dynamic visual on students' field independence-dependence on connecting errors and conceptual understanding in learning chemistry concepts with multiple representations. Seventh graders (N=123) at a co-ed middle school were assigned to a static visual (SV) group learning with text and static visual, and a dynamic visual (DV) group learning with text and dynamic visual. The students then learned 'Boyle's Law' and 'Charles's Law' for two class periods. Results revealed that the percentages of the DV group were lower than those of the SV group on connecting errors. However, the percentages of the students' connecting errors were still high regardless of their field independence-dependence. There was a little different tendency in the percentages of connecting errors between the two groups by students' field independence-dependence according to the types of connecting errors. The scores of the DV group were significantly higher than those of the SV group in a test on conceptual understanding. However, there was no significant interaction between the instruction and the students' field independence-dependence. Educational implications of these findings are discussed.

• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.1145-1153
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• 2009

The problem of Korean registered population is that population classified by age increases as one grows older until 6 age or 7 age. This paper is to suggest an algorithm of the re-projection under 7 age on Korean registered population and to analysis of comparison with the reported population statistical data. As the result, the reprojections population is trusted in the number of 0 age on the comparison of other reported population statistical data.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.683-693
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• 2012

Recently, statistical machine translation (SMT) has received many attention with ease of its implementation and maintenance. The goal of our works is to build bidirectional Korean-Japanese SMT system by using MOSES [1] system. We use Korean-Japanese bilingual corpus which is aligned per sentence to train the translation model and use a large raw corpus in each language to train each language model. The proposed system shows results comparable to those of a rule-based machine translation system. Most of errors are caused by noises occurred in each processing stage.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.482-486
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• 2004

울산지역 수질특성에 관하여 연구하기 위해 228개 지점에서 수질성분 25개 항목을 분석하였다. 그 성분중 지하수 음용수 9개 수질성분(pH, EC, TDS, Cl, Mn, NO$_3$, SO$_4$, F, Fe)에 관해 수질분포특성 및 오염도를 나타내기 위해 모수적 통계기법인 정규크리깅과 비모수적 통계기법인 지시크리깅 기법을 적용하였다. OK와 IK의 성분별 베리오그램 분석한 결과 OK의 경우 모든 수질성분은 구상형모델(Spherical model)로 선정되었으며, IK의 경우 pH, TDS, SO$_4$, Cl, Mn, F, Fe 성분은 구상형모델로, EC는 지수형모델로, NO$_3$는 선형모델로 선정되었다. 그 결과 정규크리깅의 경우 연구지역의 수질특성을 정량적 분포특성이 잘 나타났다. 특히 태화강, 인접한 남구일원과 중구일원, 북구의 북서 일원 그리고 동구의 방어동일원에서 수질성분 9개 성분들이 다소 높게 나타났다. 특히 EC, TDS 그리고 Cl$^{-}$ NO$_3$ 성분이 높게 나타났다. 그리고 지시크리깅의 경우 정규크리깅과 비교하여 이상치가 크게 영향을 미칠 수 있는 통계학적인 오류를 보완하여 분석한 결과 울산지역 9개 성분 오염도는 EC>TDS>NO$_3$>pH>Fe>Mn>Cl>SO$_4$>F 순으로 오염특성이 나타났다.