• 한국자동차공학회논문집
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• 제7권8호
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• pp.43-54
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• 1999

The effects of equivalence ratio and pressure on burnt gas temperature in premixed fuel rich propane-oxygen-inert gas combustion are investigated over the wide ranges of equivalence ration from 1.5 to 2.7 and pressure from 0.1 to 7 MPa by using a specially designed disk -type constant-voume combustion chamber, The premixtures are simultaneously ignited by eight spark plugs located on the circumference of combustion chamber with 45 degree interals. The eight converging flames compress the end gases to high pressures. The burnt gas temperature is meausured by the nmodifie dtow-colr pyrometry method. The transmissivity in the chamber center during the final stage of combustion at the hightest pressure is meausred by in situ laser extinction method. It is found that a temperature difference between the burnt gas temperature measured by mofidied and conventrational two-color method is 10 to 20 K, but the accuracy of the modified two-color methdo is higher if the local transmissivity in observed region is uniform , and the combustion at higher pressures results gas density conditions and the burnt gas temperature increases as the volume fraction of argon is increased because the specific heat of argon is lower compared to that of nitrogen with a constant equivalence ratio.

• 대한기계학회논문집B
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• 제26권2호
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• pp.238-244
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• 2002

A 5-valve(intake 3-valve) engine has been developed to increase engine performance. These engines have a high power caused by the decrease of inertia mass of an intake valve and the increase of intake effective area. In this study, in-cylinder flow patterns were visualized with laser sheet method and velocity profiles at near intake valves were inspected by using a two-color PIV. In addition, steady flow tests were performed to quantify tumble ratio of flow-fields generated by a tumble control valve(TCV). Experimental results of steady flow test show that the cure of tumble ratio in intake 3-valve engine farmed as a S shape with valve lift changes. This tendency is different from the one in intake 2-valve engine. Using laser sheet method and two color PIV method, we can find that the intake flow through upper valve increases and the velocity gradient also slightly increases as valve lift increases. From this study, the in-cylinder flow characteristics around intake valves were made clearly.

• 한국컴퓨터정보학회논문지
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• 제14권9호
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• pp.21-28
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• 2009

색상 극화란 주어진 텍스트 영역에서 글자색이 무엇인지를 결정하는 과정으로서 텍스트 추출을 위해서 선행되야 하는 작업이다. 본 논문에서는 텍스트 영역이 주어졌을 때 글자 영역을 추출하기 위한 색상 극화 기법을 제안한다. 제안된 방법은 글자 영역과 배경 영역에 대한 관찰을 바탕으로 두 영역 사이의 면적 비율과 표준편차비율의 관계를 색상 극화에 이용한다. 이를 위하여 그레이 스케일로 주어진 텍스트 영역을 Otsu의 방법으로 이진화하고 이진화된 두 영역을 각각 4-CC 레이블링한다. 레이블링된 두 그룹의 영역에 대해 각각 면적과 영역 중심으로부터의 거리에 대한 표준편차를 계산한 다음 두 그룹에서 면적이 가장 넓은 영역을 갖는 영역 사이의 면적 비와 표준편차가 가장 작은 영역들 사이의 표준편차 비를 이용하여 색상 극화를 수행한다. 다양한 폰트와 크기를 갖는 텍스트 영역에 대한 실험을 통해 제안된 방법이 강건하게 색상 극화를 수행함을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.300-310
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• 1999

A constant-volume combustion chamber is developed to measure the burnt gas temperature over the wide ranges of equivalence ratio from 1.5 to 2.7 and pressure from 0.1 to 2.7 and pressure from 0.1 to 6 MPa by two-color method. The combustion temperature is also calculated by the conventional two-region model. The premixed fuel rich propane-oxygen-inert gas mixtures under high pressures are simultaneously ignited by eight spark plugs located on the circumference of combustion chamber with 45 degree intervals. The eight converging flames compress the end gases to high pressures. The transmissiv-ity in the chamber center during the final stage of combustion at the highest pressure is measured by in situ laser extinction method. Comparisons are made with the combustion temperatures between two-color method and two-region model. It is found that the burnt gas temperature mea-sured by two-color method is higher than that calculated by two-region model because of being the negative temperature gradient on the calculation and the temperature distribution of light path-length on the measurement and the burnt gas temperature for the turbulent combustion is higher than that of the laminar combustion under the same conditions because the heat loss for turbulent combustion is lower due to the shorter combustion period.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
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• pp.124-129
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• 2004

The ratio pyrometry has been investigated experimentally for the measurement of soot particle temperatures in a diffusion flame. A tungsten lamp calibration system was constructed and used in order to calibrate the ratio pyrometry and two-color pyrometry using a KL-factor method. Once the ratio pyrometry is properly calibrated, temperatures measured using a ratio pyrometry were virtually identical to those obtained from a KL-factor method. The effect of soot volume fraction on temperature measurement was almost negligible, and therefore, the ratio pyrometry could provide the useful temperature information of sooting flames. The potential application of a ratio pyrometry to a 2-D temperature measurement without sacrificing the accuracy was demonstrated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.933-938
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• 2001

A 5-valve(intake 3-valve) engine has been developed to increase engine performance. These vehicles have a high power caused by the decrease of inertia mass of an intake valve and the increase of intake effective area. In this study, velocity profiles at near intake valves were inspected by using a two-color PIV and laser sheet method with tumble control valve(TCV). In addition, steady flow tests were performed to quantify tumble ratio on flow-fields generated with a TCV. These experimental results show that the tendency of the tunble ratio in intake 3-valve engine is different from the one in intake 2-valve engine. From this results, the intake flow characteristics around intake valves were made clear.

• Journal of the Optical Society of Korea
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• 제18권6호
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• pp.777-782
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• 2014

This paper proposes an RGB to RGBY color conversion algorithm for liquid crystal display (LCD) using RGW pixel structure with two-field (yellow and blue) sequential driving method. The proposed algorithm preserves the hue and saturation of the original color by maintaining the RGB ratio, and it increases the luminance. The performance of the proposed RGBY conversion algorithm is verified using the MATLAB simulation with 24 images of Kodak lossless true color image suite. The simulation results of average color difference CIEDE2000 (${\delta}E^*_{00}$) and scaling factor are 0.99 and 1.89, respectively. These results indicate that the average brightness is increased 1.89 times compared to LCD using conventional RGB pixel structure, without increasing the power consumption and degrading the image quality.

• 한국가시화정보학회지
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• 제17권3호
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• pp.59-65
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• 2019

Phosphor particles ((Sr,Mg)₂ SiO₄:Eu²⁺ were suspended in deionized water in quartz cuvette and used for measuring liquid temperature field by using two-color-ratio method. In the temperature range of 23~77℃, it showed the relative error from 2.4% to 4% and the temperature sensitivity of 0.65 %/℃ at 30℃ and 0.95 %/℃ at 77 ℃. This performance is comparable to measurement techniques using thermographic liquid crystal or laser induced fluorescence or other thermographic phosphor particle. Among investigated potential error sources, the particle number density affected the intensity ratio and the temperature, but the effect of laser fluence was not evident.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2001년도 Proceedings of 2001 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.100-107
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• 2001

A simple new technique of particle depth position measurement, which can be applied for three-dimensional velocity measurement of fluid flows, is proposed. Two color illumination system that intensity is encoded as a function of z-coordinate is introduced. A calibration procedure is described and a profile of small sphere is detected by using the present method as preliminary test. Then, this method is applied to three-dimensional velocity field measurement of simple flow fields seeded with tracer particles. The motion of the particles is recorded by color 3CCD camera. The particle position in the image plane is read directly from the recorded image and the depth of each particle is measured by calculation of the intensity ratio of encoded two color illumination. Therefore three-dimensional velocity components are reconstructed. Although the result includes to some extent error, the feasibility of the present technique for three-dimensional velocity measurement was confirmed.

• 산업경영시스템학회지
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• 제18권36호
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• pp.31-39
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• 1995

This study reflected sensitivity cognition in using color and evaluated the performance in task regarded GUI environment. Largely, three experiments were conducted. First, the searching time in text environment was compared with the searching time in color environment. Second, to know relationship of hue, saturation, lightness which are factors of color, and searching time, the searching time was measured using two-way ANOVA with interaction with three independent variables: hue, saturation, and distance. Third, sensitivity cognition about color was investigated and the performance of searching task was analyzed in the environment designed by color regarded sensitivity cognition. According to statistical results, the average searching time was decreased about 50.31% in color environment. The searching time was significant among the difference of hue and saturation. For the factor of color, the more the ratio of green and red was increased, the more searching time was decreased. The more the ratio of gray was increased, the more searching time was increased. And the searching time was developed in the environment designed by color regarded sensitivity. The purpose of this study is the presentation of sensitivity realization method and verification in the reflection and application of sensitivity to the industrial environment and design.