• Journal of Korea Port Economic Association
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• v.27 no.1
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• pp.185-212
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• 2011

The purpose of this paper is to show the empirical analysis way for measuring the seaport efficiency by using the previous radial model and the newly modified non-radial models( panel additive model, panel RAM model, and panel SBM model)with Spearman rank order correlation coefficient(SROCC) for 20 Korean ports during 11 years(1997-2007) for 1 inputs(port investment amount) and 4 outputs(Number of Ship Calls, Port Revenue, Customer Satisfaction Score for Port Service and Container Cargo Throughput). The main empirical results of this paper are as follows. First, consistency ratio of SROCC in terms of efficiency scores between radial and panel Additive model was over about 76% and overall consistency ratio was about 71.6%. Second, an efficiency of panel RAM model was higher than that of radial model with similarity. However, panel SBM model shows the very similar efficiency scores with panel radial model. Third, the slack size of radial model is smaller compared to non-radial model. Models' ranking orders in terms of efficiency scores, number of efficient ports are panel RAM model, panel SBM model, and radial model. The order from the minimum efficiency scores was the same order like just before. The policy implication to the Korean seaports and planner is that Korean seaports should introduce the new methods like non-radial models(panel additive model, panel RAM model, and panel SBM model) for measuring the port performance.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.425-427
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• 2012

본 논문에서는 방사적(radial) 및 비방사적(non-radial) DEA 모형을 사용하여 광산업(Photonics)의 효율성 지수를 측정하고 그 결과를 비교 분석 하였다. 분석결과, 업종별로는 광전변환기기, 광재료, 관측검사기기 분야의 효율성 지수가 1(100%)로 나타나 가장 생산적인 규모의 상태인 것으로 나타났으며, 대부분의 업종에서 종업원수의 과잉투자가 두드러지게 나타났다. 이러한 결과는 실제 투입된 인력 수준에 상응하는 성과가 실현되지 못하고 있음을 시사하는 것으로 종업원의 생산효율성을 높이려는 노력이 필요함을 알 수 있다.

• The Journal of the Acoustical Society of Korea
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• v.38 no.3
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• pp.247-255
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• 2019

In this study, to predict the noise of a submarine propeller which is going to become bigger and faster, the non - cavitating propeller noise was predicted based on the numerical analysis which considering the interaction of the hull - appendages - propeller. In order to predict the radiated noise of the propeller, the flow field for the entire region of hull-appendages-propeller was computed by CFD (Computational Fluid Dynamics). And the noise for the thickness noise and the load noise was numerically predicted using FW-H (Ffwocs Williams-Hawkings) acoustic analogy. Numerical noise prediction results were verified by model tests and showed good agreement with the measurement results in predicting total noise level and low frequency noise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.1 no.1
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• pp.83-90
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• 2000

DEA is a newly developed analyzing tool to measure efficiency evaluation of decision making units (DMU). It compares DMU by radial Projection on the efficient frontier. The purpose of this study is to show reference point approach used for searching solution in multiple objective linear Programming can be usefully used to determine flexible efficient frontier of each DMU In reference point approach, the minimization of ASF Produces an efficient points in frontier and enhances the usefulness of DEA by Providing flexibility in DEA and optimally allocating resources to DMU. Various DEA models can be supported by reference point method by changing the projection direction in order to choose the targets units, standards costs and management benching-marking.

• Environmental and Resource Economics Review
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• v.16 no.4
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• pp.873-900
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• 2007

Non-market valuation studies tend to assume that individual households have homogeneous preferences for a non-market good to value. However, since the preferences for non-market goods, especially environmental goods are more likely to be heterogeneous by nature, it may be more appropriate to assume heterogeneous preferences for non-market goods, which may in turn may lead to reduced biases in the WTP estimation. This study investigate the extent to which individual households have heterogeneous preferences for reduced concentrations of radon, a radioactive indoor air pollutant, for road safety, and for nuclear power safety. We also analyze the effect of heterogeneity assumption on the results of model and WTP estimation. Using the choice experiments and mixed logit models, we found that allowing for heterogeneous preferences improved model fitness and that there existed heterogeneous preferences for both reduced radon concentration and road safety, albeit not for nuclear power safety. The mean WTP for reduced radon concentrations and road safety increased by factors of 2.44 and l.74 respectively with the models allowing for heterogeneous preferences.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.805-809
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• 2007

최근 도시의 발달은 하상공간에 대한 이용도를 높이는 방향으로 개발이 진행되어가는 추세이며, 하상도로 및 하상주차장의 이용은 이제 도시 내에서 이용 가능한 마지막 여유 공간으로 인식될 정도로 그 의존도가 높아져가고 있다. 그러나 하상공간의 활용도가 높아져갈수록 도시홍수의 발생으로 인한 대피문제가 발생하게 되고 돌발홍수로 인하여 하상도로의 차단 혹은 하상 주차장에 주차된 차량의 소거가 늦어지는 경우 고스란히 피해를 보게 되는 등 그 부작용도 계속 증가되고 있다. 도시홍수의 특성을 살펴보면 국지성 돌발 강우에 의한 유량의 급격한 증가와 짧은 유하시간, 작은 유역면적 등에 의하여 주요 예보지점까지의 도달시간이 매우 짧아 수문학적 홍수예측 모형을 이용하여 홍수예측 업무를 수행하는데 선행시간을 충분히 확보할 수 없다는 단점을 지니고 있다. 이에 따라 본 연구에서는 기존의 하천시스템에 대한 설계 등을 목적으로 하여 모형의 적용을 통한 시뮬레이션 기법을 적용하고 이를 통하여 홍수 예경보를 발령하기에는 선행시간의 확보(대피시간의 확보)라는 측면에서 상당한 어려움을 지닐 수 있으므로 시시각각으로 측정되는 실시간 수위측정 자료 및 실시간 강우자료를 이용하여 모형의 수행과정을 생략하고 하천의 수위변동을 직접 예측하고 대피할 수 있는 시나리오 기반의 수문모형을 개발하였다. SPSS를 사용한 통계학적 모형을 대전광역시 3대 하천에 대하여 적용한 결과 예측자료가 실측자료를 고수위 및 저수위 부근에서 정확히 모의하지 못하는 경향이 나타났으나 경계 및 위험수위를 설정하고 이를 넘어가는 시점에 대한 예측을 하는 홍수경보 시점 예측에는 효율적인 적용성을 나타내었다.씬 간편하면서도 정확도가 높아서, 환경방사성 스트론튬의 정량분석에 적절히 사용될 수 있다.e form of Jones matrix, which allows a new interpretation in the conversion efficiency of the thin-film optical waveguides.있다는 장점이 있었다. 따라서 소아에서 복막투석도관 수술 시 복강경적 방법을 이용하는 것이 효율적인 복막 투석을 위해 유용하다고 생각된다.상부 방광천자에 비해 민감도 59.5%(25/42), 특이도 86.6%(13/15)였고 위양성률 13.3%(2/15), 위음성률 40.5%(17/42) 로 정확도가 낮았다. 결론 : 소변을 가리지 못하는 영유아에서 요로 감염을 진단하기 위해서는 도뇨관 채뇨에 비해 초음파 감시하 치골상부 방광천자가 정확하고 안전한 채뇨법으로 권장되어야 한다고 생각한다.應裝置) 및 운용(運用)에 별다른 어려움이 없고, 내열성(耐熱性)이 강(强)하므로 쉬운 조건하(條件下)에서 경제적(經濟的)으로 공업적(工業的) 이용(利用)에 유리(有利)하다고 판단(判斷)되어진다.reatinine은 함량이 적었다. 관능검사결과(官能檢査結果) 자가소화(自家消化)시킨 크릴간장은 효소(酵素)처리한 것이나 재래식 콩간장에 비하여 품질 면에서 손색이 없고 저장성(貯藏性)이 좋은 크릴간장을 제조(製造)할 수 있다는 결론을 얻었다.이 있음을 확인할 수 있었다.에 착안하여 침전시 슬러지층과 상등액의 온도차를 측정하여 대사열량의 발생량을 측정하고 슬러지의 활성을 측정할 수 있는 방법을 개발하였다.enin과 Rhaponticin의 작용(作用)에 의(依)한 것이며,

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.6
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• pp.757-772
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• 2019

The purpose of this paper is to measure the clustering change and analyze empirical results, and choose the clustering ports for Busan, Incheon, and Gwangyang ports by using Artificial Neural Network, Social Network, and Tabu Search models on 38 Asian container ports over the period 2007-2016. The models consider number of cranes, depth, birth length, and total area as inputs and container throughput as output. Followings are the main empirical results. First, the variables ranking order which affects the clustering according to artificial neural network are TEU, birth length, depth, total area, and number of cranes. Second, social network analysis shows the same clustering in the benevolent and aggressive models. Third, the efficiency of domestic ports are worsened after clustering using social network analysis and tabu search models. Forth, social network and tabu search models can increase the efficiency by 37% compared to that of the general CCR model. Fifth, according to the social network analysis and tabu search models, 3 Korean ports could be clustered with Asian ports like Busan Port(Kobe, Osaka, Port Klang, Tanjung Pelepas, and Manila), Incheon Port(Shahid Rajaee, and Gwangyang), and Gwangyang Port(Aqaba, Port Sulatan Qaboos, Dammam, Khor Fakkan, and Incheon). Korean seaport authority should introduce port improvement plans by using the methods used in this paper.

• Nuclear Engineering and Technology
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• v.22 no.4
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• pp.410-415
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• 1990

Prompt fission neutron energy spectrum as a function of energies of neutron inducing fission has been calculated en the basis of the Madland-Nix(MN) model. The resultant spectra have been weighted to excitation functions of $^{27}$ Al(n, $\alpha$), $^{32}$ S(n, p) and $^{115}$ In(n, n') threshold reactions in order to get the average cross sections and then spectral indices which are defined as the average cross section ratio for two selective threshold reactions among the above three. It is appeared that spectral indices together with the neutron spectra are varying with energies of neutron inducing fission. This may indicate that the prompt fission neutron energy spectrum can be determined by measuring experimentally the spectral index.

• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.507-514
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• 2015

The purpose of this study is to analyze the efficiency of resident companies in port hinterland logistics that are currently operating. The subjects of the efficiency analysis include 13 logistics hinterland resident companies in Incheon Port and Busan Port. Investment amounts, area, and number of employees were selected as input variables, and volume and sales amounts were selected as output variables. As for the efficiency analysis methods, traditional CCR and BCC models were applied. To overcome the limits of these models, a super-efficiency model and a Super-SBM model were also applied. According to the super-efficiency model analysis, the mean was 0.777 and the standard deviation was 0.54, indicating an approximate 33% difference of efficiency among the companies. According to the Super-SBM model analysis, the mean was 0.649 and the standard deviation was 0.489. When considering residuals in the super-efficiency model, the average efficiency score among the companies decreased by approximately 13%. This means that the efficiency score decrease of DMU, where non-radial residuals exist at about 18% on average. Examining the inefficiency of the inputs, the inefficiency of the number of employees turned out to be largest at -45%, compared to 'area' at -33% and 'investment amount' at -33%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.1
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• pp.13-24
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• 1983

A mathematical model for the two-dimensional unsteady flow was developed by introducing Abbott's implicit finite difference operator and double sweep algorithm, which could be applied to simulate the respose of a harbor against the intrusion of long waves through the entrance connected to open sea. In order to improve its accuracy corresponding to the field phenomena, bottom resistance, Coriolis force, wind effect terms were included and wave direction and radiating effect was considered. The result of seiche test was always stable and the amplitude was accurate. Some phase shift was occured, but it could be reduced by using small values of Courant number and many points per a wave length as well. A comparision with the Ippen and Goda's theoritical and hydraulic experimental works was fulfilled.