• Journal of Biosystems Engineering
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• v.13 no.2
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• pp.18-27
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• 1988

The basic model of impeller was developed for the theoretical analysis of performance. The developed model was tested with two different blade radius of curvature based on the pumping efficiency under the operating conditions in Korea. And the pump performance of the impeller was also tested for the various speeds. The results obtained are summarized as follows; 1. There was no significant effect on the different blade radius of curvatures on the discharge and pump efficiency. 2. Head and power requirement was increased in proportion to the blade radius of curvature. 3. In the mathematical approach of the blade radius of curvature, the method of involute curve was more recommendable as compared with the method of circular arc curve. 4. The pump efficiency of the model impeller developed based on the theoretical analysis increased about 10% more than that of the existing impeller.

• International Commerce and Information Review
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• v.14 no.4
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• pp.27-47
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• 2012

The study aims to analyze how the variables for Korea, such as the exports, imports, FDI(Inward) and FDI(Outward), influence the economic growth and how they affect each other. For the purpose of empirical analysis, this paper used the quarterly time series data from 1980 to 2010, dividing the period before and after 1997(IMF). The variables used in this study were log-transformation from the original variables. This study empirically tests the relationship among variables by using VECM with considering the time-series properties of each variable. The results found from the study are as followings. Causality analysis using VECM proved that no causality between GDP and exports existed, whereas causality between GDP and FDI(Inward) existed, in which GDP affected FDI(Inward) since IMF. However, it was found that other periods and FDI(Inward) did not affect GDF and had no causality among them.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.197-205
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• 2020

The present study analyzed the effector that has an influence on continuance intention to use YouTube that is a prime platform to distribute visual contents. Whether the dispersion of information communication technology succeeds or not is determined by a more extent which user uses active and continued than adopts fast. From this point of view, we employed partial least square(PLS) path modeling to analyze structural causality among constructs in the post-adoption model(PAM). As a result, all paths given in PAM except for the path 'confirmation-satisfaction' were validated. Especially, confirmation mediated with satisfaction than perceived usefulness has a more effect on continuance intention. Finally, we described the limitation of the present study and the suggestion for future research.

• KDI Journal of Economic Policy
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• v.35 no.2
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• pp.107-131
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• 2013

In this paper, we test and estimate the stochastic non-fundamental trend in Korean stock market. For this, following Kim (2011), we exploit that the long-run equilibrium stock price may be decomposed into fundamental and stochastic non-fundamental trends (i.e., the sum of dividend innovations and a part that are orthogonal with the dividend innovations) by using the Beveridge-Nelson decomposition and projections. In this VAR construction, there is an error correction mechanism through which stock prices converge to their long-run equilibrium, which also contain the stated stochastic non-fundamental trend as well as fundamental trend. The estimation and test results using yearly data from the Korea (1976-2012) indicated that fluctuations in stock prices during that period can be explained mainly not by the stochastic non-fundamental trend but by the dividend trend. However, during some periods like after Seoul Olympic Games, we may observe the non-fundamental trend affected to the stock price variation.

• Journal of the Korean association of regional geographers
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• v.9 no.4
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• pp.559-575
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• 2003

The purpose of this study is to systematically explain and discuss the return migration of Koreans in Central Asia to the Russian Far East. The Koreans' return migration is explained by the combination of push and pull factors inherent in the host and home countries. The structural or institutional push factors in Central Asia include the linguistic policy of a country, civil war, ethnic conflicts, while the micro ones are the Koreans' high concern of their children's education and the improvement of a socio-economic status. The macro pull factors operated in the Russian Far East are the permission to use the housing facilities and land previously controlled by military authorities and the laws of recovering the koreans' basic right and honor, while the micro ones are the networks of relatives and friends living in Central Asia and the Russian Far East. The two aspects related to the Koreans' return migration are also discussed. Firstly, the return migration of Koreans in Central Asia is interpreted as a migration of ethnic affinity. Secondly, the establishment of an autonomous district of Koreans in the Russian Far East is discussed.

• The Korean Journal of Applied Statistics
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• v.28 no.5
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• pp.871-883
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• 2015

Vector autoregressive (VAR) models in high dimension suffer from noisy estimates, unstable predictions and hard interpretation. Consequently, the sparse vector autoregressive (sVAR) model, which forces many small coefficients in VAR to exactly zero, has been suggested and proven effective for the modeling of high dimensional time series data. This paper studies coupling measures to select non-zero coefficients in sVAR. The basic idea based on the simulation study reveals that removing the effect of other variables greatly improves the performance of coupling measures. sVAR model coefficients are asymmetric; therefore, asymmetric coupling measures such as Granger causality improve computational costs. We propose two asymmetric coupling measures, filtered-cross-correlation and filtered-Granger-causality, based on the filtered residuals series. Our proposed coupling measures are proven adequate for heavy-tailed and high order sVAR models in the simulation study.

• International Area Studies Review
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• v.16 no.1
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• pp.3-27
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• 2012

This paper adopts recently developed panel unit root test that is cross-sectionally robust. Cointegration test is also used to find whether regional house prices are in line with gross regional domestic production (GRDP) in the long run in Korea during 1989-2009. Based on the panel VECM and the panel ARDL models, we examine causal relationships among the variables and estimate the long-run elasticity. We find evidence of cointegration and bidirectional causal relationships between regional house prices and GRDP. The results of long-run estimates, using both fixed effect and ARDL models, show that house prices positively and significantly influence on the GRDP and vice versa. Together with these results, the findings of ARDL-ECM imply that there exists a long-run equilibrium relationship between house prices and regional economic variables even if there is a possibility of short-run deviation from its long-run path.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.669-679
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• 2008

정보사회의 도래와 인터넷의 확산으로 정보보호의 중요성이 증가함에 따라 기업과 조직에 있어서 정보보호는 경쟁적 우위를 확보하기 위한 도구임과 동시에 비즈니스를 안정적으로 수행하기 위한 필수 경영요구사항으로 등장하고 있다. 또한 기업자산의 일원으로써 보호되어야 하는 유 무형 정보자산의 가치는 더욱 높아지고 있으며, 이를 관리하는 조직과 기업의 효율적이고 효과적인 정보 자산 관리 및 정보보호 투자에 대한 중요성이 부각되고 있다. 그러나 조직의 정보보호 투자가 증가함에도 불구하고 이에 대한 성과측정을 위한 체계적 방법이 제시되지 않아 정보보호 투자 의사결정 및 개선방향 도출에 어려움이 있다. 기존의 재무적 측면위주의 정보보호 투자효과 분석은 정보보호 투자의 기회비용적인 특징으로 인해 체계적인 효과 분석 및 현황을 파악하기에는 부족하며 향후 정보보호 투자의 전략추진방향을 제시하기 어렵다. 본 논문에서는 정보보호 투자효과의 특성을 고려하여 균형성과표(Balanced Scorecard, BSC)관점의 정보 보호 투자 전략과 성과에 대한 인과관계를 분석하고자 한다. 따라서 기존 정보보호 투자효과 분석의 선행연구를 중심으로 핵심성공요인과 측정지표를 도출하고, 관련 기업 및 조직을 대상으로 설문조사를 통해 수집된 자료를 구조방정식모형(Structural Equation Model, SEM) 분석기법을 활용하여 실증분석 하고자 한다.

• Environmental and Resource Economics Review
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• v.21 no.3
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• pp.493-517
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• 2012

This paper analyzes a price discovery process for gasoline among branded and independent stations in Korea using a vector error correction model (VECM) and directed acyclic graphs (DAG). Two data sets for daily prices of medium level gasoline running from April 15, 2008 to May 31, 2009 and from January 1, 2011 to December 31, 2011 are used for empirical analysis. Empirical results show that S-OIL has an exogeneity and played a important role in the flow of price information in the market in the first period. In the second period, SK energy played a key role in price discovery process in the market. The price of NH-OIL stations do not cause the price of any other stations, which implies that the entrance of new branded stations with lower gasoline price to market has no influence on gasoline prices of retail markets.

• Journal of the Korean Society for information Management
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• v.17 no.1
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• pp.129-148
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• 2000

Experiments were performed on three subsets of a Korean test collection in order to determine whether 2-Poisson model's Z value is a good measure for selecting subject words from a document to be indexed. It was found that subject word selection based on the Z value was effective for only one subset with short texts, i.e., the Science and Technology subset. Correlation analyses between 2-Poisson model's Z and TF.IDF weight for the three subsets showed that the correlation was relatively high for two test subsets with short texts, i.e., the Science and Technology subset and the Newspaper subset.