• Journal of Korea Water Resources Association
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• v.37 no.2
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• pp.121-131
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• 2004

SIMHYD and TANK model are used to predict time series of daily rainfall-runoff of Soyang Dam and Youngcheon Dam watershed. The performances of SIMHYD model with 7 parameters and TANK model with17 parameters are compared. Three optimization methods (Genetic algorithm, Pattern search multi-start and Shuffled Complex Evolution algorithm) were applied to study-areas with 3 different types of objective functions. Efficiency of TANK model is higher than that of SIMHYD. Among different types of objective function, Nash-sutcliffe coefficient is found to be the most appropriateobjective function to evaluate applicability of model.

• Environmental and Resource Economics Review
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• v.30 no.1
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• pp.79-105
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• 2021

In the circumstance of standing out the climate change issue, the purpose of this study is to compare the efficiency of offshore and coastal fisheries according to whether or not greenhouse gas (GHG) emissions are considered, and then to present policy alternatives based on the analysis results. For analysis, the traditional data envelopment analysis (DEA), the slacks-based measure (SBM) and the SBM-undesirable models were used, and robust analysis of variance (ANOVA) and Wilcoxon Signed-rank tests were performed. As a result, the study showed that the average efficiency of fisheries decreased as the traditional DEA extended to the SBM model considering the slack and the SBM-undesirable model including the GHG emissions. Specifically, the average efficiency of the traditional DEA model, SBM model, and SBM-undesirable model was analyzed as 0.7350, 0.5820 and 0.4976 respectively. In addition, the results of the robust ANOVA and Wilcoxon Signed-rank tests all showed that there are statistically significant differences in efficiency between offshore and coastal fisheries as well as among traditional DEA, SBM and SBM-undesirable models. As a policy alternative to the analysis, it was suggested that to improve the efficiency of coastal and offshore fisheries, it is necessary to actively implement the new fishing vessel project and develop smart and electric hybrid fishing vessels.

• Journal of Korea Port Economic Association
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• v.26 no.2
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• pp.139-149
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• 2010

This paper analyses the relative efficiency of 13 container terminals based on the data for the period 2003-8 to offer a fresh perspective. There has been abundant empirical research undertaken on the technical efficiency of Busan and Gwangyang port. Most studies have focused on the use of parametric and non-parametric techniques to analyse overall technical efficiency. Here, the framework assumes that terminals use two input to produce one output; the former includes container yard and container crane and the latter container volume. Jarque-Bera indicates that three variables are not normally distributed and the positive skewness shows that all the variables have long right tails. This means there are many small-scaled container terminals. This paper also employs heteroscedastic Tobit model to show the effect of the explanatory variables on the container terminal efficiencies. The Tobit model shows that both container yard and container cranes have positive effect on the container terminal efficiency, but container yard has a higher impact on the efficiency than the container crane.

• Journal of Korea Port Economic Association
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• v.28 no.1
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• pp.53-82
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• 2012

The purpose of this paper is to show the clustering trend by using the context-dependent and measure-specific models for 38 Asian ports during 10 years(2001-2009) with 4 inputs and 1 output. The main empirical results of this paper are as follows. First, clustering results by using context-dependent and measure-specific models are same. Second, the most efficient clustering was shown among the Hong Kong, Singapore, Ningbo, Guangzhou, and Kaosiung ports. Third, Port Sultan Qaboos, Jeddah, and Aden ports showed the lowest level clustering. Fourth, ranking order of attractiveness is Guangzhou, Dubai, HongKong, Ningbo, and Shanghai, and the results of progressive scores confirmed that low level ports can increase their efficiency by benchmarking the upper level ports. Fifth, benchmark share showed that Dubai(birth length), and HongKong(port depth, total area, and no. of cranes) have affected the efficiency of the inefficient ports.

• Journal of Korea Port Economic Association
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• v.26 no.2
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• pp.82-98
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• 2010

The purpose of this paper is to suggest the efficiency measurement way of Korean seaport by using Average Index Transformation model of fuzzy DEA(Data Envelopment Analysis). Two inputs[cargo handling capacity, and berthing capacity], and outputs[cargo handling amount, and the number of ship calls] are used in 1995 and 2004 for 26 Korean seaports. Empirical main results are as follows: First, Tongyung, Gohyun, Okpo, and Sogcho Ports are efficient, and Yeasu Port shows the high efficiency level over 95% under input oriented CCR model. Gohyun and Sogcho Ports showed the most efficient score under average index transformation model. Okpo and Yeasu Ports increased their efficiency scores as the lamda(λ) values are up. The empirical results of fuzzy DEA average index transformation model for Wando, Yeasu, and Seoguipo ports showed that if the lamda values are higher, the efficiency scores are also higher. The main policy implication based on the findings of this study is that the management manager of Ministry of Land, Transport and Maritime Affairs in Korea should introduce the fuzzy DEA average index transformation model for deciding the size of inputs including the port investment amount and evaluating the port efficiency.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.245-246
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• 2012

최근 항만 투자 성과 제고를 위해 항만의 효율성을 중시하고 있는 추세이다. 향후 항만 경영을 위한 개선점을 제시 하고자 하며 운영전략 및 발전전략을 모색 할 수 있도록 기여하고자 한다.

• Journal of Navigation and Port Research
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• v.39 no.1
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• pp.55-60
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• 2015

The purpose of this study is to suggest a major strategy to become effective for each port in Northeast Asia by analyzing the relative efficiency of each port to determine the current level of efficiency, efficient harbors plan. Individual port of the major 16 ports in Northeast Asia was analysed targeting efficiency and relative efficiency. In this study, DEA technique was used. Of the DEA model, CCR (constant returns to scale) models and BCC (variable return to scale) model was applied to analyze the efficiency and effectiveness of the port. Then the efficiency measured through CCR model is again compared with the efficiency measured by the BCC model. In this way, the empirical analysis includes the input factors of the operating ports such as the number of berths, wharf, depth, total area of the pier, C / C numbers and output elements includes the container throughput. The results of the study show that most of the ports in China is efficient whereas those in Korea and Japan are relatively inefficient. There are some pairs of ports which has the similar input factors, like Busan port and Shanghai port, Lianyungang port and Incheon port, Dalian port and Gwangyang port, but the container throughput of them has a huge difference.

• Management & Information Systems Review
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• v.31 no.1
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• pp.273-292
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• 2012

This paper attempts to analyze the efficiency of Korean Materials and Components Industry. 48 sample companies are extracted and efficiency analysis for them are accomplished by using DEA model. We use both CCR-I model and BCC-I model and classify the 48 companies into two groups; efficient and inefficient companies. We find the reference set which inefficient companies should benchmark in order to achieve efficiency and present the improving values for input and output variables. We analyze whether the inefficiencies come from scale or inefficient operation by measuring the scale efficiency. Finally the ranking among the efficient companies is derived through the super-efficiency analysis.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.661-664
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• 2004

본 연구는 DEA기법을 이용하여 14개의 국내 은행의 상대적 효율성을 평가하였다. 효율성 평가에 있어서 은행을 중개기관 접근방법에서 평가하였으며, 투입물과 산출물을 선정하는 데 있어서 신탁계정과 은행계정별로 구분하여 연구를 수행하였다. 또한 규모의 효율성을 평가하기 위해 CCR모형과 함께 BCC모형을 이용하여 효율성을 평가하였다. 분석결과 신탁계정과 은행계정의 효율성은 차이가 있었으며, 대부분의 은행들이 DRS의 규모의 효율성에 있는 것으로 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1410-1414
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• 2010

최근 들어 가뭄과 국지성 호우 등의 기상이변이 지속적으로 발생하고 있으며, 이는 국민 삶의 발전과 향상에 밀접한 관계가 있는 것으로 전세계적으로 이에 대한 관심이 증가하고 있는 추세이다. 특히 댐의 효율적 관리와 안정적인 운영은 홍수피해 방지, 안정적인 용수공급과 같은 국민 생활과 밀접한 관계를 가지고 있어 수자원의 효율적인 운영과 이용은 장기적인 관점을 통하여 수립해야 한다. 이와 같이 댐 유입량의 예측은 유출모형의 목적 중 중요한 부분으로 확정론적 모형이 시 혹은 일유량과 같은 매우 짧은 시간의 유출을 예측하는데 주로 사용되지만 이는 매개변수의 추정이 불가능하거나 실제유역에서의 측정이 불가능 할 경우에는 모형적용에 한계가 있다. 이에 반해 추계학적 모형에 의한 유출예측은 장기간의 유출을 과거자료의 통계학적 특성변수를 매개변수로 하여 예측하는 방법으로 모형의 적용에 필요한 매개변수가 적어 그 적용성이 간편한 장점이 있다. 본 연구에서는 계절형 ARIMA모형을 적용하여 과거자료의 적용범위, 매개변수의 산정, 적합성 판정에 대하여 판단하고, 이 모형이 월유입량의 예측에 적합한지를 검토하였다.