돼지 관상동맥 스텐트 재협착 모형에서 MAC(脈:Maximum Arterial Re-Creation)Stent와 Palmaz Stent의 비교

배열,정명호,장양수,차광수,박종철,서정평,안영근,박주형,조정관,박종춘,강정채,박옥규 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.1

공동주택 리모델링에 따른 실 깊이 변화로 인한 빛환경 문제 개선 방안

배열관,한용구,윤종호,진경일 대한건축학회지회연합회 2008 대한건축학회지회연합회 학술발표대회논문집 Vol.2008 No.1

These day, Many people are interested in remodeling which gets less expenses of new buildings according to deteriorating many buildings. So, the government reduce 15years of remodeling terms to 15years after may of 2008. But, remodeling of apartment buildings didn't expand right and left or before and behind side. Accordingly, the problem about light environment is passed by reducing daylight factor. Now, we offer solutions to settle light environment problems of a apartment building in remodeling

기계학습모델을 통한 응급실 폐렴환자의 사망예측 모델과 기존 예측 모델의 비교

배 열,문형기,김수현 대한응급의학회 2018 대한응급의학회지 Vol.29 No.5

Objective: Machine learning is not yet widely used in the medical field. Therefore, this study was conducted to compare the performance of preexisting severity prediction models and machine learning based models (random forest [RF], gradient boosting [GB]) for mortality prediction in pneumonia patients. Methods: We retrospectively collected data from patients who visited the emergency department of a tertiary training hospital in Seoul, Korea from January to March of 2015. The Pneumonia Severity Index (PSI) and Sequential Organ Failure Assessment (SOFA) scores were calculated for both groups and the area under the curve (AUC) for mortality prediction was computed. For the RF and GB models, data were divided into a test set and a validation set by the random split method. The training set was learned in RF and GB models and the AUC was obtained from the validation set. The mean AUC was compared with the other two AUCs. Results: Of the 536 investigated patients, 395 were enrolled and 41 of them died. The AUC values of PSI and SOFA scores were 0.799 (0.737-0.862) and 0.865 (0.811-0.918), respectively. The mean AUC values obtained by the RF and GB models were 0.928 (0.899-0.957) and 0.919 (0.886-0.952), respectively. There were significant differences between preexisting severity prediction models and machine learning based models (P<0.001). Conclusion: Classification through machine learning may help predict the mortality of pneumonia patients visiting the emergency department.

관동맥 질환자에서 혈중 Apolipoprotein A-1과 Apolipoprotein B

배 열,유제영,조인종,류문희,서정평,길광채,박주형,정명호,조정관 대한순환기학회 1995 Korean Circulation Journal Vol.25 No.5

2次元 移流-分散 모델에 의한 地下水 汚染의 數値解析

李熙榮,裵烈鎬,鄭經泳,丁仙吉 서울시립대학교 산업기술연구소 1994 산업기술연구소논문집 Vol.2 No.-

In this study, it aims to analysis the advection-dispersion of groundwater pollution in saturated aquifer and to develop the numerical model for the advection-dispersion equation. At the first, finite element method(Galerkin type) is used to simulation solute transport in Eulerian approach. At the second, Eulerlian-Lagrangian method is used to simulate solute transport which adopts a Lagrangian viewpoint when dealing with the advection terms and an Eulerian viewpoint when dealing with the dispersion terms in the solute transport equations. At the last, the numerical results were compared with analytical solutions. The results are as follows. First, Eulerlian-Lagrangian method is more stable than finite element method for the numerical dispersion and diffusion in two dimensional solute transport equation. Second, in finite element method the RMS errors are increased if the peclet number is greater than two, so that is unstable, when comparing with Eulerlian-Lagrangian method. Third, Especially in the case of the advection-dominated, Eulerlian-Lagrangian method is more stable than finite element method and eliminates numerical dispersion and oscillation for all cases investigated with peclet numbers ranging from 1 two 10.

Eulerian-Lagrangian 방법을 이용한 이송-확산방정식의 분석

李熙榮,裵烈鎬,鄭經泳,丁仙吉 서울시립대학교 산업기술연구소 1994 산업기술연구소논문집 Vol.2 No.-

In this study, Eulerian-Lagrangian method(ELM) for one & two dimensional advection-dispersion equation is studied. Advection-dispersion equation is decoupled into two terms of advection and dispersion The advection equation has been solved using the method of characteristics following fluid particles along tile characteristic line. The results are interpolated onto an Eulerian grid on which the dispersion equation is solved by Crank-Nicolson type finite difference method. In solving the advection equation, Lagrangian 2-order, 3-order, 4-order interpolation polynomials, and Hermite 3-order interpolation polynomials schemes are tested for 1-dimensional model, Lagrangian 2-order are used for 2-dimensional model. Among those, Lagrangian 4-order interpolation polynomials are superior to other interpolation polynomials. ELM model for governing flow of advection is thought that it is exact model.

포화대수층 바닥에 있는 DNAPL의 용해

정경영,배열호,최상일,이희영 대한토목학회 1996 대한토목학회 학술발표회 논문집 Vol.1996 No.2

DNAPL Pool의 용해실험에 의한 분산계수 산정

정경영,배열호,최상일 한국지하수토양환경학회 1996 지하수토양환경 Vol.1 No.1

물에 쉽게 용해되지 않고 분리된 유체면을 갖는 액체를 NAPO(nonaqueous phase liquids)이라 한다. 유기용제와 석유탄화수소와 같은 NAPL에 의한 지하수 오염은 지하에서의 장기간의 지속성 및 다량의 지하수를 오염시키는 능력 때문에 주요 관심 대상물질이다 누출된 DNAPU(denser- than-water NAPL)은 궁극적으로 포화 대수층을 통과하여 바닥에 DNAPL pool을 이루게 된다. 이러한 pool로부터의 용해는 분자확산계수, 연직분산도, 지하수유속, 용해도 및 pool의 길이에 지배된다. 본 연구에서는 이러한 DNAPL pool의 용해를 모사하기 위해 DNAPL용해실험을 하여 연직 횡분산계수를 산정하였다. 본 연구에서 사용된 실험조건하에서 수행한 실험결과 산정된 연직 횡분산계수는 침투유속이 59.2cm/day, 94.3cm/day 및 158.0cm/day인 경우 각각 1.86$cm^2$/day, 2.90$cm^2$/day 및 4.51$cm^2$/day 이었고, 연직 횡분산도는 0.03024cm 이었다. Nonaqueous phase liquids(NAPL) not readily dissolved in water exist as a separate fluid phase. Groundwater contamination by NAPL such as organic solvents and petroleum hydrocarbons becomes major public concerns because of their long-term persistence in the subsurFace and their ability to contaminate large volumes of wate. Dense.-than-water NAPL(DNAPL) spilled into the subsurface penetrate through the saturated zone and ultimately form DNAPL pools on the bottom of the aquifer. The dissolution of DNAPL from these pools depends on the molecular diffusion coefficient, the vertical dispersivity, the groundwater velocity, the solubility, and the pool length. In this study, the vertical transverse dispersion coefficients for simulating the dissolution of DNAPL from such pools were obtained from the dissolution experiment. Under the experimental conditions used, the vertical transverse dispersion coefficients calculated were 1.86$cm^2$/day, 2.90$cm^2$/day and 4.51$cm^2$/4ay for seepage velocities of 59.2cm/day, 94.3cm/day and 158.0cm/day, respectively. And the vertical transverse dispersivity was 0.03024cm.

단기간의 홍수에 의한 하상변동의 예측모형

표영평,신철식,배열호 한국수자원학회 1997 한국수자원학회논문집 Vol.30 No.6

본 연구에서는 하도 내에서의 부정류 유사이송으로 인한 하상변동의 일차원적 수치모델들을 개발하였다. 유사량과 하상변동에 대한 수치해를 얻기 위해 흐름의 방정식은 Preissmann 음해법과 Lax-Wendroff 2단 양해법을 그리고 유사의 연속방정식은 시간 전방차분, 공간 중앙차분 양해법을 사용하여 수치 적분하였고, Lax-Wendroff 기법 내에서 상류와 하류의 추가 경계조건을 구하기 위해 특성곡선법을 적용하였다. 모델의 정확도는 부피보존실험을 통하 One-dimensional numerical models using finite difference methods for unsteady sediment transport on alluvial river channel are developed. The Preissmann implicit scheme and the Lax-Wendroff two-step explicit scheme with the Method of Characteristics for w

침전지내 유출웨어 부하율에 따른 탁도제거효율 변화

최계운(Gye Woon Choi),김기훈(Gi Hun Kim),배열호(Yeol Ho Bae),임부상(Boo Sang Lim),김정현(Jeong Hyun Kim) 한국수처리학회 1997 한국수처리학회지 Vol.5 No.4

In this paper, experimental studies for obtaining turbidity removal efficiencies by changing the outlet weir loading in the sedimentation basin are conducted. The experiments are conducted through the outlet weir loading of 178, 290, 368, 393, 445, 480㎥day/m in the real water treatment plant having the capacity of 110,000㎥/day. To prevent the problem of incorrect water distribution between the sediment basins, only one sediment basin was used during the experimental period of September 13, 1997 to September 24, 1997. The turbidity removal efficiencies by changing the outlet weir loading in the sedimentation basin are obtained through the comparison of the turbidities between the inflow before the rapid mixing basin and the outflow after the outlet weir. The turbidity removal efficiencies by changing the outlet weir loading are plotted in the figure and the optimum regression line is obtained through the least square method. The line is indicated with the equation of y=-0.07076x+107.23562, where y is the turbidity removal efficiency in % and x is the weir loading in ㎥/day/m. As shown in the figure, the turbidity removal efficiency of 90% in the sedimentation basin is indicated in the outlet weir loading of 240㎥/day/m and the turbidity removal efficiency of 85% in the sedimentation basin is indicated in the outlet weir loading of 315㎥/day/m. Those values are less than the weir loadings of 350∼400㎥/day/m which are suggested as the standard weir loading in the water supply design standard.