• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.713-722
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• 2010

This paper has assessed the flow patterns and settling efficiency in the sedimentation basin using the particle tracking method of the CFD code and has reached the following conclusions: In the original design where no baffle is installed in the sedimentation basin, a large recirculating area where the flow stagnates is created in the right side of the sedimentation basin, with most of the particles moving to the left side of the sedimentation basin following the flow. This biased flow structure in the sedimentation basin reduces the residence time of particles and thereby undermines settling efficiency. The biased flow toward the left side of the sedimentation basin is alleviated by installing a baffle in the sedimentation basin, promptly reducing the fast flow of over 0.7 m/s in the inlet of the sedimentation basin to the rate below 0.2 m/s. In this paper's simulation conditions, if a one-sided baffle is to be installed in the sedimentation basin, placing it 15 meters away from the basin's inlet leads to the best settling efficiency; it has also been analyzed that installing a two-sided baffle-rather than a one-sided one-is a better option in terms of settling efficiency. The highest settling efficiency of 96.2% is achieved when the underwater length of the two-sided baffle is set at 8 meters.

• Fire Science and Engineering
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• v.21 no.2 s.66
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• pp.64-73
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• 2007

The absorption characteristics of hazardous materials onto human body and defense mechanism differ from each other region within the respiratory tracts, thus adverse health effects of inhaled smokes are associated with not only the concentration but also the location of the particles deposited. In this work, the deposition fraction per surface area and the deposition sites of the smoke particles in human respiratory tracts for each rest and light exercise conditions together with oral and nasal breathing were calculated by using segmental volume tracking method. The results would be used for deriving the amount of absorption of hazardous materials onto human body, thus contribute to the health risk assessments of inhaled fire smokes.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2579-2584
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• 2007

A digital micro holographic particle tracking velocimetry (HPTV) system consisting of a high-speed camera and a single laser with acoustic optical modulator (AOM) chopper was established. The digital micro HPTV system was applied to water flow in a micro curved-tube for measuring instantaneous 3-D velocity field data consecutively. The micro curved-tube is using to reproduce the dorsal aorta or utilize in various lap-on-a-chip. The temporal evolution of a three-dimensional water flow in the micro curved-tube (the curvature, ${\kappa}$=1/${\phi}$, 2/${\phi}$, 4/${\phi}$, 8/${\phi}$) of 100 ${\mu}m$ and 300 ${\mu}m$ inner diameters was obtained and mean velocity field distribution was obtained by statistical-averaging the instantaneous velocity fields.

• Journal of Power System Engineering
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• v.16 no.3
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• pp.37-43
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• 2012

감온액정을 추적입자로 사용한 PIV(Particle Image Velocimetry)법이 온도장을 정량적으로 가시화하기 위하여 사용되었다. 이 방법은 전체 유동장과 온도장을 동시에 계측할 수 있는 방법이지만, 온도장의 온도는 온도에 따라 변화되는 액정의 색을 정량적 온도 값으로 변환시켜야한다. 따라서 본 연구에서는 감온액정에 의한 온도장의 광학적 정보를 정량적 온도로 변환시키는 신경회로망 보정기법을 개발하여 그 타당성을 검토한 후, 수직온도구배를 가진 액체의 기포에 의한 대류유동에 적용하여 기포에 의한 온도혼합과정을 정량적으로 가시화하고자 한다.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.5
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• pp.591-597
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• 1997

Instantaneous velocity distribution within coaxial circular pipe for measurement velocity of high speed is acquired simultaneously by applying the 2-dimensional PTV system consisting of a pulse generator(AOM:Acousto-Optical Modulator), a continuous-output laser and a PC image grabber together with experimental apparatus. The basic mechanism of AOM and vector identification method and performance-related image processing techniques are discussed. Representative measuring regions $90{\times}90$mm are selected and instantaneous vectors are represented and fully developed turbulent flow of maximum velocity up to about 1.0 m/sec is obtained.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.177-178
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• 2006

Digital holographic particle tracking velocimetry (HPTV) is developed by single high-speed camera and single continuous laser with long coherent length. This system can directly capture 4000 hologram fringe images for 1 second through a camera computer memory. The 3D particle location is made of the reconstruction by using a computer hologram algorithm. This system can successfully be applied to instantaneous 3D velocity measurement in the water flow inside a micro-tube. The average of 100 instantaneous velocity vectors is obtained by reconstruction and tracking with the time of evolution of recorded fringes images. In the near future, we will apply this technique to measure 3D flow information inside various micro structures.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.109-113
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• 2007

Micro-PIV is a well-known method for measurement of two- dimensional, two-component velocity in the microfluidic devices. Lots of the micro fluidic devices generate three-dimensional flow and 3D measurement of velocity is helpful to understand the physics of micro flow phenomena. In this study, we developed new micro 3D measurement method by applying 2-frame PTV in stereoscopic micro system. In this study, we did the validation study of SMPTV by using the simulated flow model to verify the accuracy and the feasibility of measurement and compared with SMPIV method. The results showed that SMPTV provides better spatial resolution and measurement accuracy than SMPIV method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.1
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• pp.1-8
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• 2009

Recently microscale biofluid flows have been receiving large attention in various research areas. However, most conventional imaging techniques are unsatisfactory due to difficulties encountered in the visualization of microscale biological flows. Recent advances in optics and digital image processing techniques have made it possible to develop several advanced micro-PIV/PTV techniques. They can be used to get quantitative velocity field information of various biofluid flows from visualized images of tracer particles. In this paper, as new advanced micro-PIV techniques suitable for biofluid flow analysis, the basic principle and typical applications of the time-resolved micro-PIV and X-ray micro-PIV methods are explained. As a 3D velocity field measurement technique for measuring microscale flows, holographic micro-PTV method is introduced. These advanced PIV/PTV techniques can be used to reveal the basic physics of various microscale biological flows and will play an important role in visualizing veiled biofluid flow phenomena, for which conventional methods have many difficulties to analyze.

• Journal of the Korean Society of Visualization
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• v.19 no.2
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• pp.32-40
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• 2021

Vapor-driven solutal Marangoni flow is governed by the concentration distribution of solutes on a liquid-gas interface. Typically, the flow structure is investigated by particle image velocimetry (PIV). However, to develop a theoretical model or to explain the working mechanism, the concentration distribution of solutes at the interface should be known. However, it is difficult to achieve the concentration profile theoretically and experimentally. In this paper, to find the concentration distribution of solutes around 2D droplet, the reverse tracking method with an artificial neural network based on PIV data was performed. Using the method, the concentration distribution of solutes around a 2D droplet was estimated for actual flow data from PIV experiment.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.6
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• pp.355-365
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• 2022

This paper addresses the problem of real-time tracking a high-speed ballistic target. Particle filters can be considered to overcome the nonlinearity in motion and measurement models in the ballistic target. However, it is difficult to apply particle filters to real-time systems because particle filters generally require much computation time. This paper proposes an accelerated particle filter using graphics processing unit (GPU) for real-time ballistic target tracking. The real-time performance of the proposed method was tested and analyzed on a widely-used embedded system. The comparison results with the conventional particle filter on CPU (central processing unit) showed that the proposed method improved the real-time performance by reducing computation time significantly.