• Journal of Korean Society for Atmospheric Environment
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• 제9권E호
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• pp.390-396
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• 1993

복잡한 광화학반응을 간략하게 처리하는 방법을 개발하고 다단계 액상반응 중에서 산의 생성에 직접 관련이 없는 반응을 생략하여 공학적 산침적모델을 개발하였다. 이러한 공학적모델의 개념을 적용하여 Sulfur Transport Eulerian Model II(STEM II)로 부터 STEM-ENG를 제작하였다. STEM-ENG를 이용하면 STEM II보다 CPU를 약 30배나 절약할수 있으면서도 STEM-II와 비견할 만한 정성적 결과를 얻을 수 있는 한편, 유기화합물이 산성물질과 오존형성에 미치는 영향의 크기를 예측할 수 있다. STEM-ENG는 workstation은 물론이고 PC를 사용하여도 운영이 가능하여 적은 비용으로 대기질을 평가할 수 있게한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.935-940
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• 2005

We are faced with water pollutions on a population explosion. Considering the importance, we research European rivers based on OECD reports. Observations in the reports have defects that make evaluation of environmental situations be difficult. By using interpolations in the compensation quantitative structure-activity relation ships (CQSAR), we complement the defects in the water quality of rivers through big cities. Thus, we get complete data set for dissolved oxygen, biochemical oxygen demand, and total phosphorus. Using the data set, we examine re-naturalization of the Rhein and the Donau in Germany. We investigate the effect of dams between Slovakia and Hungary, by using reconstructions of neural networks in CQSAR. The reconstructions have functions to extract a principal relation. On the investigation, we examine assertions of conservation groups. As the result, we confirm the re-naturalization is effective, and find a negative effect of the dam construction on changes of dissolved oxygens in the Hungary Donau. We investigate the Seine and the Thames, too.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 A
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• pp.11-14
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• 2004

In recent, the importance and necessity of some studies on reliability evaluation of grid comes from the recent black-out accidents occurred in the world. The quantity evaluation of transmission system reliability is very important under competitive electricity environment. The reason is that the successful operation of electric power under the deregulated electricity market depends on transmission system reliability management. This paper introduces features and operation modes of the Transmission Reliability Evaluation for Large-Scale Systems(TRELSS) Version 6.2, a program made in EPRI, for assessing reliability indices of composite power system. The package accesses not only bulk but also buses indices for reliability evaluation of composite powers system. The characteristics of the TRELSS program are illustrated by the case studies using the KEPCO system

• 한국전산유체공학회지
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• 제18권2호
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• pp.41-48
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• 2013

Ice accretion on the solid surface is an importance factor in assessing the performance of aircraft and wind turbine blade. Changes in the external shape due to ice accretion can greatly deteriorate the aerodynamic performance. In this study, a three-dimensional upwind-type second-order positivity-preserving finite volume CFD scheme based on the unstructured mesh topology is developed to simulate two-phase flow in atmospheric icing condition. The code is then validated by comparing with NASA IRT experimental data on the sphere. The present results of the collection efficiency are found to be in close agreement with experimental data and show improvement near the stagnation region.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.273-274
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• 2008

Recently, the most wide-area blackout in North America, Canada and Europe had shown us indirectly the importance of Wide-Area Power System Protection and had influence on the direction of domestic electric power industry. After reorganization of the electric power industry in 2001, market incentives controls the power generation, transmission and distribution rather than stability of power grid, and moreover it produce bad results like inefficient facility management and too much competition. In addition, we can easily predict the massive loss of social and economic when the wide-area outage occurs by north direction load flow which is a pending problems of domestic power system and in a changed industry likes hi-tech manufacture and information technology industries. This paper introduces the development of infra systems for prevent wide-area blackout in situations of the power system operations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2355-2357
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• 1999

Estimating equivalent soil model which represents an actual soil structure and its electrical characteristics, is extremely improtant for good substation grounding system design and analysis. Since the equivalent soil model is deduced based on the measured apparent soil resistivity - generally obtained from Wenner's 4-point method, reasonable and accurate measuring technique and procedure guarantee good grounding system design and analysis. The paper aims to show the importance of reasonable enough probe spacing by presenting the influence of soil modelling to estimation and measurement of grounding resistance of substation grounding grid.

• 대한조선학회논문집
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• 제41권1호
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• pp.47-54
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• 2004

The friction drag reduction of a ship is of prime importance for the design and production of high-valued/high-tech ship. Thus, this study carried out the development of reliable numerical tools to identify the friction drag reduction mechanism for turbulent boundary layer on the ship surface and to deduce the optimum reduction technique by numerical experiment. The developed LES and DNS numerical tools were applied to simulate the turbulent channel flow These results were very well matched with previous results not only qualitatively but also quantitatively. The parallelization using MPI (Message Passing Interface) technique implemented in the developed code to speed up the simulation and to obtain the accurate results from the fine grid system was testified its computational efficiency.

• 통합자연과학논문집
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• 제4권2호
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• pp.99-102
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• 2011

Effect of protonation and deprotonation of ionization compounds is an important application in Comparative molecular field analysis (CoMFA). There are enough information's were reported about different CoMFA applications such as Series design and selection of training set, Geometries and optimizations of molecules, Effect of partial atomic charges, bioactive conformations and alignment, Interaction energy fields, Effects of different grid spacing etc. However limited information's are available about the ionization of compounds. This study aimed at the critical review of about the effects of protonation of ionizable molecules and its impact on the predictability of CoMFA models. We also discussed about previous implications and the things needed to be considered to come for a final conclusion about its impact on CoMFA predictability.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.62-66
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• 2003

In recent, the importance and necessity of some studies on reliability evaluation of grid comes from the recent black-out accidents occurred in the world. The quantity evaluation of transmission system reliability is very important under competitive electricity environment. The reason is that the successful operation of electric power under the deregulated electricity market depends on transmission system reliability management. This paper introduces features and operation modes of the Transmission Reliability Evaluation for Large-Scale Systems(TRELSS) Version 5_1, a program made in EPRI, for assessing reliability indices of composite power system. The package accesses not only bulk but also buses indices for reliability evaluation of composite powers system. The characteristics of the TRELSS program are illustrated by the case studies using the IEEE 25buses system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.67-70
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• 2003

In recent, the importance and necessity of some studies on reliability evaluation of grid come from the recent black-out accidents occurred in the world. The quantity evaluation of transmission system reliability is very important under competitive electricity environment. The reason is that the successful operation of electric power under the deregulated electricity market depends on transmission system reliability management. The various results of many case studies for the IEEE 25buses system using the Transmission Reliability Evaluation for Large-Scale Systems(TRELSS) Version 5_1, a program made in EPRI are introduced in this paper. Some sensitivity analysis has been included. This paper suggests that the some important input parameters of the TRELSS can be determined optimally from this sensitivity analysis for high reliability level operation of a system.