• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.213-215
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• 2006

This study presents an application of GIS technologies to construct the graphic user interface for 3-dimensional exhibition of the results obtained by ocean hydrodynamic model. In coastal management studies, GIS provide a receptacle for scattered data from diverse sources and an improvement of the 3D visualization of such data. Within the frame of a GIS a variety of analytical, statistical and modeling tools can be applied to transform data and make them suitable for a given application. A 3D hydrodynamic model was driven by time-dependent external forcing such as tide, wind velocity, temperature, salinity, river discharge, and solar radiation under the open boundary condition. The Jinhae Bay was selected as a case study. Here, we have used GeoMania v2.5 GIS software and its 3D Analyst extension module to visualize hydrodynamic model result that were simulated around the Jinhae Bay.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1694-1697
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• 2008

하절기의 태풍 및 장마시 유입되는 탁수는 수자원의 효율적 관리를 저해하는 요소로서, 현재 일부댐에 이러한 탁수의 장기화를 방지하고 탁수로 인한 하류부의 영향기간을 줄이기 위하여 선택취수시설이 설치되어 운영중에 있으며, 많은 댐을 대상으로 탁수발생 현상에 대하여 모델링 기법을 이용한 탁수거동 분석이 수행되고 있다. 본 연구에서는 태화강수계의 대곡천에 위치한 대곡댐 및 사연댐에 대하여 강우시 호내에 유입된 탁수의 거동을 분석하기 위하여 CE-QUAL-W2 모형을 구축하였다. 유입 탁도자료는 2007년 하절기 강우시 실측된 결과를 이용하였으며, 탁수가 유입된 이후 일별로 호내에서 측정된 수심별수온 및 탁도자료를 이용하여 모델을 보정하였다. 유입 이전의 조사시 표층 및 심층의 수온차이가 $1^{\circ}C$ 미만으로서 수온성층이 형성되지 않은 것으로 나타났으며 고탁수 유입시 탁수층이 중층 이하에서 바닥층까지로 유입되는 것으로 나타났으며, 보정결과 침강보다 자연적인 소멸 등의 침강 외적인 요인으로 인하여 탁도가 저감되는 것으로 분석되었으며 이에 대한 추가적인 검토가 필요한 것으로 판단되었다. 댐축에의 탁수층 도달시간을 검토한 결과 대곡댐은 18시간 이내, 사연댐은 30시간 이내에 댐축에 도달하는 것으로 예측되었다. 댐별 저수용량이 각각 9월 14일 기준으로 $10.3\;Mm^3$ 및 $17.2\;Mm^3$으로서 60% 가까운 차이를 보이나, 9월 18일 기준으로 $18.2\;Mm^3$, $24.2\;Mm^3$로 나타나 각각 $7.9\;Mm^3$, $7.0\;Mm^3$의 저수용량증가를 나타내었다. 실제로 유입된 양의 차이는 크지 않은 반면에 초기 체적의 차이가 크게 나타남($10.3\;Mm^3$, $17.2\;Mm^3$의 약 60% 차이)으로써 이러한 탁수층이 댐축에 도달하는 시간의 차이가 발생한 것으로 판단된다.

• Geotechnical Engineering
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• v.14 no.6
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• pp.45-56
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• 1998

In order to select a proper ground improvement technology and to assess the quality and rate of improvement in the soft deposits. it is essential to characterize in-situ properties of the soft marine clay layer that may have many thin silt or sand seams. In this paper, both piezocone and flat dilatometer tests were performed to characterize in situ properties of a marine clay. Both tests provided quite similar site classifications, and in both tests the penetration pore water pressure was the better indicator for the classification of marine clay layer, especially in which sand or silt seams are frequently interbedded. Undrained strengths determined by both the cone tip resistance and the excess pore water pressure measured from piezocone were very similar in clayey soil layers. And the untrained strength determined by dilatometer had an approximately average value of undiained strengths obtained from piezocone. In addition, the theoretical time factor that can consider pore pressure dissipation effect during cone penetration may provide a reliable estimation of the coefficient of consolidation, especially for a coastal site which includes many silt or sand fractions or seams.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.167-172
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• 2000

This paper is aimed at developing an location tracking for mobile station employing currently available mobile communication network of cellular phone and PCS(Personal Communication System). When the location tracking of mobile stations is in services, the services such as Emergency-119, crime investigation, effective urban traffic management or the safety protection of Alzheimer's patients, ran be available. This paper is to track the mobile station in communication network in NLOS environment. To achieve reduction of the standard noise, Kalman filter is used. In terms of the distance, positions are located by using TOA and TDOA methods in the environment that removes NLOS bias in the measured data. And then smoothing method is used. to achieve reduction of the position error values

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.5
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• pp.147-155
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• 1993

An urban runoff model is proposed in this study, which is composed of a surface runoff model and a channel routing model. ILLUDAS is selected as the best fit model for the surface runoff computation, and the dynamic wave model using weighted four-point implicit finite difference scheme is used to perform the channel routing. The 3rd Seongbook bridge basin located in Seoul is selected as the test basin for the proposed model, and the rainfall-runoff data are collected to calibrate and verify the urban runoff model. The computed results by this model showed the fair accuracy when compared with the observed hydrographs. So the model proposed in this study could be used to compute the urban river flow as well as the outflow from the urban drainage area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1087-1094
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• 2013

This study aims at enhancing the objective estimation of social cost of air quality due to mobile emission. More specifically, it examines the difference between the daily oriented and hourly oriented estimation results of social air quality cost and draws implications from the comparative analysis. The result indicates that the social cost of air quality differs up to approximately 24 times depending on the analysis time period. Moneywise, the difference between daily and hourly assignments amounts to the average of 653.5 billion won whereas only 1% of error occurred in the estimation result based on peak and nonpeak based hourly assignment. This study reaffirms the need for time-based travel demand management for emission reduction, and confirms the feasibility of emission estimation by travel demand forecasting method over the conventional method employed by the CAPSS.

• Journal of Korea Water Resources Association
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• v.48 no.11
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• pp.957-967
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• 2015

It was reviewed for the 2D numerical simulations to evaluate the effects of flood control by detention basin, even if stage-discharge relationships for the side weir were not known. A 2D depth-integrated numerical model was constructed by the application of the finite volume method to the shallow water equations as a numerical method and the introduction of an approximate Riemann solver for the accurate calculation of fluxes. Results by the model were compared with those by the laboratory test for the cases of free overflow and submerged flow over a side weir between the channel and storage. The difference between simulated and measured discharge coefficients for the case of free overflow is very small. In addition, the results by simulations were in good agreement with those by experiments for the submerged flow over a side weir and its mechanism was reproduced well. Through this study the discharge coefficients of side weirs can be accurately determined by the 2D numerical model and a considerable degree of accuracy can be achieved to evaluate the effect of flood defenses by detention basins. Thus, it will be expected to apply this model practically to the plan of detention basins, the evaluation of design alternatives, or the management of the existing ones.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.335-335
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• 2011

토양유실은 농업환경지표를 비롯한 국제 규범에서 농업에 의한 환경오염의 핵심문제로 제기되고 있다. 이러한 토양유실의 문제점을 해결하기 위해 USLE를 기반으로 한 SATEEC모형을 사용하여 토양유실량 및 유사량을 산정하였다. SATEEC모형은 USLE입력자료와 DEM을 이용하여 산정된 토양유실량 과 GA-SDR모듈을 통해 산정된 유달률(Sediment Delivery Ratio, SDR)을 통하여 최종유출구에서의 유사량을 산정한다. 많은 연구자들은 최종유출구에서의 유사량을 실측유사량과 비교하여 비슷하게 모의되면 유역의 특성을 잘 반영한다고 판단하므로 SATEEC모형의 단점인 토양유실량이 과하게 산정되는 문제점을 중요하게 생각하지 않는다. 하지만 SATEEC 모형의 결과값인 유사량의 신뢰도를 향상시키기 위해서는 토양유실량 검증을 통한 정확한 입력자료 구축이 필요하다. 따라서 본 연구에서는 여러개의 토양유실량 시나리오를 만들어 이에 따른 SATEEC 모형의 유사량을 비교/평가하고, 이를 이용하여 토양유실량의 검증이 필요함을 제시하고자 한다. 본 연구에서 사용한 토양유실량 시나리오는 총 4개로써, 시나리오 1은 SATEEC모형을 이용하여 산정된 토양유실량이며, 시나리오2~4는 ArcGIS를 사용하여 기존의 토양유실량 값에 ${\pm}0.25$의 범위를 주어 새롭게 산정된 토양유실량으로 SATEEC모형을 이용한 유사량 산정시 입력자료로 활용하였다. 그 결과 SATEEC모형을 이용하여 산정된 토양유실량은 시나리오별로 차이를 보였다. 또한 SATEEC GA-SDR모듈을 통해 예측된 토양유실량 값과 실측유사량을 이용하여 유달률을 산정하였으며 유달률도 토양유실량 시나리오별로 차이를 보였다. 따라서 SATEEC모형을 이용하여 최종유출구에서의 유사량 산정 결과 토양유실량의 차이에도 불구하고 유사량은 거의 비슷한 값을 나타내고 있으며, 최종유출구에서의 모의된 예측 유사량이 실측유사량과 비교 시 R2=0.688, EI=0.643 정도로 실측유사량과 비슷한 경향을 나타냈다. 따라서 SATEEC모형을 이용하여 유사량 산정시 먼저 문헌을 통한 토양유실량 검증이 필요하리라 판단되며, 문헌을 통해 토양유실량 검증 후 정확한 입력자료를 구축하여 유역에서의 유사량 저감을 위한 최적관리 기법 분석에 사용할 수 있도록 프로세서를 구축해야 할 것이라 판단된다.

• The Korean Journal of Applied Statistics
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• v.22 no.3
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• pp.531-539
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• 2009

Logistic regression is widely used as a datamining technique for the customer relationship management. The maximum likelihood estimator has highly inflated variance when multicollinearity exists among the regressors, and it is not robust against outliers. Thus we propose the robust principal components logistic regression to deal with both multicollinearity and outlier problem. A procedure is suggested for the selection of principal components, which is based on the condition index. When a condition index is larger than the cutoff value obtained from the model constructed on the basis of the conjoint analysis, the corresponding principal component is removed from the logistic model. In addition, we employ an algorithm for the robust estimation, which strives to dampen the effect of outliers by applying the appropriate weights and factors to the leverage points and vertical outliers identified by the V-mask type criterion. The Monte Carlo simulation results indicate that the proposed procedure yields higher rate of correct classification than the existing method.

• Fire Science and Engineering
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• v.19 no.1 s.57
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• pp.20-28
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• 2005

Major petrochemical companies in the USA and the EU map out the strategies step-by-step hazard evaluation for the efficient risk management. They adopted the risk screening methods, such as Dow fire & explosion index, as a preliminary phase to execute detailed evaluation such as QRA (Quantitative Risk Assessment). In this study, The FEDI (Fire & Explosion Damage Index), which a kind of risk screening method proposed by Khan and Abbasi, was applied to the BTX plant in Korea. We showed that the FEDI can be effectively used to classify the hazard potential by comparison of the result from the FEDI and the result from QRA. And we showed that the characteristics and the quantities of chemical are the factors which have a largest effect on fire and explosion by executing relative sensitivity analysis of the FEDI. In conclusion, if the FEDI was applied as a preliminary phase of HAZOP, more efficient hazard evaluation can be possible.