• 한국가시화정보학회지
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• 제4권2호
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• pp.3-5
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• 2006

Recently, the next-generation advanced flow visualization techniques such as holographic PIV, aynni.c PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced mea-surement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. They would be indispensable in solving complicated thermo-fluid flow problems not only in industrial fields such as automotive, space, electronics, aero- and hydro-dynamics. steel, and information engineering, but also in the research fields of medical science, bio-medical engineering, environmental and energy technology etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is impossible for conventional measurement methods to observe the nano- and bio-fluidic flow phenomena. In this article, the basic principle of these high-tech flow visualization techniques and their practical applications which cannot be resolved by conventional methods, such as blood flows in a micro-tube, in vivo analysis of micro-circulation, and flow around a living body are introduced as a blue ocean strategy.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.277-283
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• 2015

Background: Foodborne disease outbreaks from various food sources are a major health concern worldwide. Current methods for detection of foodborne pathogens are both expensive and time-consuming. Purpose: This review aims to present the current information available on the use of lateral flow test strips to detect pathogens in food products to enhance food safety. Results: Frequent foodborne disease outbreaks from various food sources have increased the need for rapid and easy methods for routine analysis of foodborne pathogens. Present detection methods for foodborne pathogens require expensive instruments, experts, and long time for sample analysis. Lateral flow test strips have drawn attention in recent years because of their ability to detect analytes quickly and easily. This review focuses on the principle of the lateral flow test, the various formats of lateral flow test strips, recognition elements, labeling tags, and reading instruments. In addition, this review also discusses the future prospects for the lateral flow test strips.

• 동력기계공학회지
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• 제8권1호
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• pp.36-40
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• 2004

Two-phase loop systems using the latent heat capacity of their working fluids can meet the increasing power requirements and are well suited to thermal management systems of future large applications, due to its abilities to handle large heat loads and to provide them at uniform temperatures regardless of the changes in the heat loads. Therefore some experiments on the effect of the gas and liquid superficial velocities, $j_G,\;j_L$ on flow pattern transition, void fraction and frictional pressure loss were performed on a co-current air-water flow in an adiabatic horizontal tube. The flow patterns were depended on the superficial velocity of each phase. It snowed that the increasing $j_L$, resulted in a significant increase in the frictional pressure loss for all flow patterns, at a constant $j_G$. The experimental results were also evaluated with some of existing models and correlations.

• 대한의용생체공학회:의공학회지
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• 제13권3호
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• pp.209-216
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• 1992

A new experimental technique is proposed to localize the flow limiting segment(FLS) during forced expiration. The present technique is based on the pressure drip across FLS and a consequent change in airway resistance, which can provide an accurate and objective location of FLS. During forced expiratory maneuver artificially induced by a strong negative pressure (-100mmHg) applied at the trachea in an anesthetized open chest dog, airway resistance( R) was calculated from air flow and airway pres- sure signals at various airway locations and lung volumes, At the lung volumes above 10 % VC, FLS located in the trachea 6cm lower from the larynx. With the lung volume decreased below 8% VC, FLS jumped upstream to End-3rd generation of the airway. These results were similar with the previous reports from excised dog lungs, which demonstrated the validity of the present technique. Since the present technique provides a more objective measure of FLS location, it would be useful in future studies of expiratory flow limitation.

• 물과 미래
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• 제14권1호
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• pp.31-37
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• 1981

금강수계의 미계획지점에 대한 갈수량빈도곡선의 합성은 하천형태학적 인자인 유역면적, 유역의 기복량, 하천의 연장 및 미국연방주환경국의 하천수질기준인 10년 7월 평균 갈수량을 이용한 상관관계를 분석함으로서 가능하였다.

• 전자통신동향분석
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• 제27권2호
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• pp.129-136
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• 2012

OpenFlow 기술은 기존의 폐쇄적인 네트워킹 기술을 개방형 네트워킹 기술로 변화시켜서 새로운 네트워킹 기술 발전을 위한 기반을 제공하였다. OpenFlow 기술의 상용화 및 표준화를 촉진시키기 위해서 설립된 ONF(Open Networking Foundation)는 네트워킹 기술을 컴퓨팅 기술로 재해석하고 OpenFlow 기술을 기반으로 SDN(Software-Defined Networking) 기술을 정의하였다. SDN 기술은 네트워크 비용 및 복잡성을 근본적으로 해결하는 기술로, 기존 네트워킹 기술의 하드웨어 및 소프트웨어 기술을 근본적으로 변화시키는 미래인터넷 기술로 떠오르고 있다.

• Korea-Australia Rheology Journal
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• 제21권3호
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• pp.161-173
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• 2009

This study analyzes especially drag and lift models recently developed for fluid-solid, fluid-fluid or liquid-liquid two-phase flows to understand their applicability on the computational fluid dynamics, CFD modeling of pulsatile blood flow. Virtual mass effect and the effect of red blood cells, RBCs aggregation on CFD modeling of blood flow are also shortly reviewed to recognize future tendencies in this field. Recent studies on two-phase flows are found as very useful to develop more powerful drag-lift models that reflect the effects of blood cell's shape, deformation, concentration, and aggregation.

• International Journal of Aeronautical and Space Sciences
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• 제11권4호
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• pp.319-325
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• 2010

For decades, researchers have rigorously studied the characteristics of flow traveling around blunt objects in order to gain greater understanding of the flow around aircraft, vehicles or vessels. Many different types of flow exist, such as boundary layer flow, flow separation, laminar and turbulent flow, vortex and vortex shedding; such types are especially observed around circular cylinders. Vortex shedding around a circular cylinder exhibits a two-dimensional flow structure possessing a Reynolds number within the range of 47 and 180. As the Reynolds number increases, the Karman vortex changes into a three-dimensional flow structure. In this paper, a numerical analysis was performed examining the flow and aero-acoustic field characteristics around a circular cylinder using an optimized high-order compact scheme, which is a high order scheme. The analysis was conducted with a Reynolds number ranging between 300 and 1,000, which belongs to B-mode flow around a circular cylinder. For a B-mode Reynolds number, a proper spanwise length is analyzed in order to obtain the characteristics of three-dimensional flow. The numerical results of the Strouhal number as well as the lift and drag coefficients according to Reynolds numbers are coincident with the other experimental results. Basic research has been conducted studying the effects an unstable three-dimensional wake flow on an aero-acoustic field.

• 한국농공학회논문집
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• 제57권4호
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• pp.73-84
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• 2015

An embankment raising project on 113 agricultural reservoirs in Korea was implemented in 2009 to increase water supply capacity for agricultural water and instream uses. This study evaluated the future water supply capacity of the Imgo reservoir at which the agricultural reservoir embankment raising project was completed, considering climate change scenarios. The height of the embankment of the reservoir was increased by 4.5 m, thereby increasing its total storage from 1,657.0 thousand to 3,179.5 thousand cubic meters. To simulate the reservoir water storage with respect to climate changes, two climate change scenarios, namely, RCP 4.5 and RCP 8.5 (in which greenhouse gas reduction policy was executed and not executed, respectively) were applied with bias correction for reflecting the climate characteristics of the target basin. The analysis result of the agricultural water supply capacity in the future, after the agricultural reservoir embankment raising project is implemented, revealed that the water supply reliability and the agricultural water supply increased, regardless of the climate change scenarios. By simulating the reservoir water storage considering the instream flow post completion of the embankment raising project, it was found that water shortage in the reservoir in the future is not likely to occur when it is supplied with an appropriate instream flow. The range of instream flow tends to decrease over time under RCP 8.5, in which the greenhouse gas reduction policy was not executed, and the restoration of reservoir storage was lower in this scenario than in RCP 4.5, in which greenhouse gas reduction policy was executed.

• 한국전자거래학회지
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• 제24권1호
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• pp.91-103
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• 2019

기업 입장에서 앞으로 있을 현금흐름에 대한 예측이란, 향후 발생할 수 있는 유동성(현금부족) 위험을 미리 파악할 수 있다는 점과 미래의 투자계획을 세우는데 중요한 자료가 될 수 있다는 점에서 중요한 의의를 지닌다. 그러나 기업 간 거래에서 매출 채권 형태로 발생하는 거래 유형은 다른 유형의 거래와는 달리 채무 이행 불확실성이 존재하며, 이로 인해 정확한 현금흐름 예측을 어렵게 한다. 본 연구에서는 추계적 분석 기법의 하나인 가변 마코프 기법(Variable Order Markov model)을 활용하여 기업 간에 발생 할 수 있는 매출 채권과 관련한 현금흐름 동향을 예측한다. 구체적으로는, PST(Probabilistic Suffix Tree)라는 가변 마코프 기법을 활용하여, 지난 과거의 매출 채권 발행 및 수금 내역을 바탕으로 해당 매출 채권들의 기대 연령 예측 연구를 수행하였다. 본 연구결과를 통해, 기존의 다른 기법들과 대비하여 가변 마코프 기법을 활용 시, 평균 12.5% 이상의 정확도를 보여주고 있음을 밝혔다.