• Journal of Korean Society of Transportation
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• v.27 no.6
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• pp.45-53
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• 2009

This study presumes the efficiency of each route by utilizing data of Seoul's exclusive bus routes for the 2008 and the DEA model. In the estimation, it is assumed that the number of passengers and profits of each route is calculated by considering the number of buses and stops, travel distance, intervals and management cost. This study computed the efficiency scores of each bus line in Seoul based on the data for the first half of 2008 and one of the DEA models, namely the BCC model. After analysis using the input-oriented BCC model, out of a total of 18 lines of interest, there were 2 CRS lines and 16 IRS lines. Also, the Tobit Regression Analysis that helps identify the impact of the elements used in the analysis on efficiency scores proved that the most influential element to exclusive buses is the length of intervals.

• Journal of Korea Water Resources Association
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• v.46 no.6
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• pp.629-642
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• 2013

In this study, the efficiency of the by-pass fishway installed at Kangjung-Goryong Weir in Nakdong River was assessed by using River2D which is a two-dimensional physical habitat simulation model. The model was calibrated and validated through the measured water elevation. The assessment was performed according to flow condition such as flood, normal, and low flow. Especially the low flow condition was focused on because the target fish, Zacco Platypus, have moved frequently up and downstream at the spawning season from April to June. From simulation results, it can be deduced that the influx efficiency and the passage efficiency of the fishway in the low flow is higher than that in the flood and normal flow due to occurrence of proper velocity at fishway entrance.

• Journal of Energy Engineering
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• v.17 no.1
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• pp.31-37
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• 2008

At present, the target amount of demand-side management and investment cost of EE (Energy Efficiency) program, which consists of high-efficiency appliances, has been estimated simply by the diffusion function based on the real historical data in the past or last year. In the internal and external condition, the penetration amount of each appliance has been estimated by Bass diffusion model which is expressed by time and three coefficients. And enough acquisition of real historical data is necessary for reasonable estimation of coefficients. In energy efficiency, to estimate the target amount of demand-side management, the penetration amount of each appliance should be primarily forecasted by Bass diffusion model in Korea. On going programs, however, lightings, inverters, vending machine and motors have a insufficient real historical data which is a essential condition to forecast the penetration amount using a Bass diffusion model due to the short period of program progress. In other words, the forecast of penetration amount may not be exact, so that it is necessary for the method of forecast to apply improvement of method. In this paper, the penetration amount of high-efficiency appliances is forecasted by Bass, virtual Bass, Logistic and Lawrence & Lawton diffusion models to analyze the diffusion progress. And also, by statistic standards, each penetration is compared with historical data for model suitability by characteristic of each appliance. Based on the these result, in the forecast of penetration amount by diffusion model, the reason for error occurrence caused by simple application of diffusion model and preferences of each diffusion model far a characteristic of data are analyzed.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.3
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• pp.13-22
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• 2008

The objective of this study is to evaluate the applicability of extracted PRMS input parameters by KGIS-Hydrology over Yongdam-Dam watershed. KGIS-Hydrology is a system for automatic extraction and analysis of watershed characteristic data. Input parameters of PRMS were generated from GIS data (DEM, soil, forest type, etc.) using KGIS-Hydrology. Multi-temporal meteorological data from Jangsu station of KMA (Korea Meteorological Administration) were used for all simulation periods. Input parameters of PRMS were optimized using observed runoff data of Yongdam-Dam station (1966-2001) and validated using observed runoff data of Yongdam-Dam station (2002-2006, Yongdam-Dam watershed). The results showed that the simulated flows were much closed to the observed flows of Yongdam-Dam (2002-2006) and Donghyang (2001-2004) station by 0.49~0.83 and 0.57~0.75 model efficiencies, respectively.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.147-158
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• 2007

This study attempted to determine a suitable hydrologic model for assessing the impact of climate change on water resources, and to assess the accuracy of streamflow scenarios simulated by the selected hydrologic model using the meteorological scenarios of the Seoul National University Regional Climate Model(SNURCM). Comparison of four water balance models and two daily conceptual rainfall-runoff models for the simulation capability of the Daecheong Dam inflow indicated that the abcd model performs the best among the tested water balance models and performs as well as SSARR that is popular as a daily rainfall-runoff model in Korea. Parameters of the abcd model were then estimated for 12 ungauged subbasins of the Geum River by the regionalization method. The model parameters were first calibrated at nine multi-purpose dams and were then regionalized using catchment characteristics for another four multi-purpose dams, which were assumed to be ungauged sites. The model efficiency(ME) coefficients of the simulated inflows for these four dams were at least 87%. The MEs of the hindcasted meteorological rainfall scenarios of the 12 subbasins of the Geum River were more than 60%. Moreover, the ME of the Daecheong Dam inflow simulated by the abcd model using the SNURCM rainfall scenarios was more than 80%. Therefore, this research concluded that the abcd model coupled with the SNU-RCM meteorological scenarios can be used for impact assessment studies of climate change on water resources.

• Journal of Korea Port Economic Association
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• v.30 no.1
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• pp.23-55
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• 2014

The purpose of this paper is to show the clustering trend and to choose the clustering ports for 3 Korean ports(Busan, Incheon and Gwangyang Ports) by using the self organizing maps based on neural network(SOM) and Tier models for 38 Asian ports during 11 years(2001-2011) with 4 input variables(birth length, depth, total area, and number of crane) and 1 output variable(container TEU). The main empirical results of this paper are as follows. First, clustering results by using SOM show that 3 Korean ports[Busan(26.5%), Incheon(13.05%), and Gwangyang(22.95%) each]can increase the efficiency. Second, according to Tier model, Busan(Hongkong, Sanghai, Manila, and Singapore), Incheon(Aden, Ningbo, Dabao, and Bangkog), and Gwangyang(Aden, Ningbo, Bangkog, Hipa, Dubai, and Guangzhou) should be clustered with those ports in parentheses. Third, when both SOM and Tier models are mixed, (1) efficiency improvement of Busan Port is greater than those of Incheon and Gwangyang ports. (2) Incheon port has shown the slow improvement during 2001-2007, but after 2008, improvement speed was high. (3) improvement level of Gwangyang port was high during 2001-2003, but after 2004, improvement level was constantly decreased. The policy implication of this paper is that Korean port policy planner should introduce the SOM, and Tier models with the mixed two models when clustering among the Asian ports for enhancing the efficiency of inputs and outputs.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.583-586
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• 2007

본 논문에서는 삼수원신안강모형(三水源新安江模型)으로 한국 위천유역에 대하여 홍수예보를 모의하였다. 결과 신안강모형(新安江模型)은 위천유역의 홍수를 비교적 정확하게 모의하였고 평균 모형 효율성 계수는 0.93이나 되었으므로 홍수예보를 적용하는데 적합하다. 신안강모형(新安江模型)은 습윤 반습윤지구의 축만유출(蓄滿流出)의 모형으로서 초기 토양함수량이 풍부한 흥수에 대해서는 정확도가 매우 높다. 그러므로 홍수예보를 하는데 있어서 신안강모형(新安江模型)이 광범한 실용가치가 있다고 예상된다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.548-551
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• 2004

합리적인 업무 수행도의 예측을 통해 기업은 기존 업무절차의 평가뿐 아니라 업무 개선방안과 새로운 업무의 설계기준을 제시할 수 있다. 본 연구는 업무효율지표들 중 가장 중요한 요소인 업무절차의 수행시간을 예측하는 모형을 제시한다. 일반적으로 기업의 업무는 예측가능하며 장기적으로 안정된 성격을 가진다. 우리는 이러한 특성을 바탕으로 한 대기행렬 모형을 구축하고 그것을 분석하여 정적인 방식의 업무실행 시 수행시간을 예측하였다. 그리고 모형의 성능을 시뮬레이션 기법을 사용하여 평가하였다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.09a
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• pp.398-405
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• 1995

원자력 분야의 연구개발사업은 원자력 연구개발 중장기 사업이 시작됨에 따 라 국가적 차원의 연구사업으로 변화하고 있다. 따라서 연구개발 투자효율의 극대화를 위해서 원자력이라는 종합과학기술분야의 특성을 감안한 연구평가 기법 및 평가방법등이 설정되어야 한다. 이를 위하여 연구개발과제에 대한 평가방법의 과학화를 위하여 많은 노력을 기울이고 있으며 앞으로도 계속 수정.보완해 나가야 한다. 본 논문에서는 연구개발평가 모형 설정시 일반적 으로 검토되어야 할 사항에 대하여 설명하였고 지금까지 개발된 연구평가 모형에 대한 구체적인 내용을 제시하였으며, 또한 현 평가모형의 문제점 및 앞으로 개선해 나아가야 할 방향을 제시하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1585-1588
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• 2005

무선통신 환경에서 TCP의 효율성을 개선하기 위한 ECN 방법을 하나의 페트리 넷 모형으로 표현한 사례가 있다. 이 경우에는 모형이 너무 복잡하여 ECN 방법의 구조를 한눈으로 파악하기 어렵다는 단점이 있다. 본, 논문은 기존의 모형을 추상화하여 계층적으로 표현한 결과를 보인다. 계층적 표현은 시스템 전체 구조를 이해하기가 용이하다는 장점이 있다..