• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.1307-1310
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• 2005

본 연구에서는 보다 효율적인 트래픽 분산과 안정적인 망을 제공할 수 있도록 하기 위하여, 인터넷 ISP 트래픽을 분석하였다. 이를 위하여, 국내 ISP 중 하나인 드림라인에서 발생하는 인터넷 트래픽을 시간별, 지역별로 분석하였으며, 특정 지역에서 장애가 발생한 경우 유연한 대처를 위하여 망에서 준비하여야 하는 트래픽 비율을 분석하였다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.3
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• pp.94-102
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• 2007

In this paper, we consider a line balancing problem in hybrid flowshops where each workstation has identical parallel machines. The number of machines in each workstation is determined in ways of satisfying pre-specified throughput rate of the system. To minimize the total number of machines in the systems, we propose five heuristic methods and one simulated annealing method. Extensive computational experiments found the superiorities of two heuristic methods and the meta-heuristic.

• Journal of the KSME
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• v.27 no.3
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• pp.198-202
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• 1987

PLC의 도입이 10여년 남짓된 지금, 자동화의 추세는 기능의 다양함과, 빠른 제어 속도, 높은 신뢰도가 요구되어 전기적인 제어에서 전자적인 제어로 전환되어 가고 있다. 특히 주 컴퓨터와 연결하여 생산 및 판매, 관리 부시 등에 정보를 신속히 제공할 수 있어 여러모로 편리하다. 이와 같은 흐름은 전문적인 지식을 필요로 하지 않고 프로그램의 작성 및 수정이 용이하며 시스템고 장수리시 PLC의 기능에 의해 간단히 해결되고 새로운 전자제품의 개발로 점점 더 가격이 싸지 고 있다는 점을 감안할 때 FMS(flexible manufacturing system)를 실현하고자 하는 모든 기업에 그 응용이 예상된다.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.189-192
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• 2003

최근 석유공급의 불안정과 에너지 소비의 급격한 증가로 인하여, 국가적인 차원에서의 에너지 절약사업이 주요 시책으로 추진 중에 있으며, 전력사업에서도 에너지 절감이라는 차원뿐만 아니라 경영에 직결되는 중요한 과제로 전력손실에 대한 관심이 높아져가고 있다. 특히, 전력시장 자유화라는 흐름 속에서 전력손실 문제는 전기요금의 산정에 있어서 합리적인 근거를 제시한다는 점에서 중요한 관심 사항이 되고 있다. 본 논문에서는 올바른 배전손실 계수를 적용하여 배전사업자가 배전망을 효과적으로 운용하여 손실을 최소화할 수 있도록 유도하며, 전력공급 전반의 효율성을 향상시킬 수 있도록 손실관리 가이드라인을 제시하고자 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1463-1476
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• 2014

In order to understand hydrodynamic and morphodynamic characteristics under wave-current interactions in an estuary, a coupled model for two-way analysis between existing 3-d numerical wave tank and newly-developed 3-d morphodynamic model has been suggested. Comparing to existing experimental results it is revealed that computed results of the newly-suggested model are in good agreement with each laboratory test result for wave height distribution, vertical flow profile and topographical change around ocean floor pipeline in wave-current coexisting field. Also the numerical result for suspended sediment concentration is verified in comparison with experimental result in solitary wave field. Finally, it is shown that the 3-D coupled Hydro-Morphodynamic model suggested in this study is applicable to morphological change under wave-current interaction in an estuary.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.4
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• pp.339-345
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• 2008

The stratified flow can be seen in the oil and gas pipelines as well as pipelines related to ship's fluid machineries. Numerous theories and correlations have also been proposed in the past for the prediction of stratified flow in horizontal or slightly inclined pipe. The previous researches are mostly about the effects of physical properties, viscosity, phases densities and pipe geometries on the stratified flow. Very few study outcomes exist on the effect of gravity magnitude and large slop angle of pipe inclinations on the occurring condition of stratified flow. In this study, therefore, analytical procedures were conducted about the effect of both the change in the gravity magnitude and pipe inclinations on the stratified flow occurring conditions. From the analytical results, it was found that stratified flow occurred at the vertical upward inclination and at very low liquid phase flowrates in 0.17g and 0.33g conditions.

• Journal of Korea Water Resources Association
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• v.49 no.12
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• pp.961-969
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• 2016

Due to the recent requirement of installing low-head structures considering environmental aspects, various types of fixed weir have been suggested. However, the design guideline of transverse structures for practical application is very limited. The purpose of the present study is to analyze the hydraulic properties of the fixed weirs installed at the small and middle sized rivers of Korea depending on the physical specifications to provide fundamental data that may be reflected to the design of a low-head fixed weir considering the relevant environmental aspects. The basic discharge coefficient of slope-type and step-type weirs depending on change of crest was estimated, and a stage-discharge curve was developed. In addition, the flow properties under free flow and submerged flow conditions were analyzed by varying the hydraulic conditions such as discharge and crest.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.9-16
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• 2016

During the 2004 Niigata-ken Chuetsu, Japan, earthquake, more than 1,450 underground structures, known as sewer manhole, were uplifted up to 1.5m in Nagaoka and Ojiya city. The uplift damage can be a serious matter because they not only hinder the flow of wastewater systems, as a part of lifeline systems, but also disturb traffic flows. For restoration works, an open-cut investigation of damaged wastewater system was conducted by the Nagaoka city government. The results from the investigation compiled valuable data sets for buried pipeline damage due to earthquakes. In the present study, the factors affecting the uplift amount of the underground structure is investigated by using the data sets which include locations of damaged sections and inclination of pipeline before and after the earthquake and the SPT borehole logs in the affected area. Correlation analysis between the underground structure uplift and the geological settings in the affected area revealed that ground water depth and original subsoil, including thickness of clay layer, SPT N-value and fill thickness are the key parameters for the uplift phenomenon.

• Journal of the Korean Institute of Gas
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• v.2 no.4
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• pp.7-17
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• 1998

This study is to develop the consequence modeling methodology for quantitative prediction of the hazard distance(or toxic buffer distance) for two-phase flow continuous releases from the pressurized chlorine saturated liquid storage tank of the chemical plant facilities. The source term modeling was peformed by the refined analysis method based on USEPA's guideline and SuperChems model self-calculation, respectively. The hazard distance was predicted for STEL, IDLH and ERPGs(ERPG-2 and ERPG-3) concentrations being used as the toxic regultaion concentration in hazard estimation. To use as hazard estimation guideline for the establishment of the emergency response planning, the effects of source characteristics and meteorological vaiations on the hazard distance was especially considered for ERPG-2 concentration.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.67-75
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• 2013

In this paper, an analytical model is presented for the source/drain parasitic resistance of FinFET. The parasitic resistance is a important part of a total resistance in FinFET because of current flow through the narrow fin. The model incorporates the contribution of contact and spreading resistances considering three-dimensional current flow. The contact resistance is modeled taking into account the current flow and parallel connection of dividing parts. The spreading resistance is modeled by difference between wide and narrow and using integral. We show excellent agreement between our model and simulation which is conducted by Raphael, 3D numerical field solver. It is possible to improve the accuracy of compact model such as BSIM-CMG using the proposed model.