• 한국분무공학회지
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• 제7권3호
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• pp.31-37
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• 2002

In previous study, diesel-methanol stratified injection system is manufactured and applied to a D.I. diesel engine in order to realize combustion improvement using methanol, which is oxygenated fuel with large latent heat. We know that NOx and soot is reduced by stratified injection of diesel fuel-methanol. Therefore, in the present study, combustion diagnosis using optical measurement is tried to make clear effect of methanol on simultaneous reduction of NOx and soot. Two-color method is used to measure flame temperature and KL value, which is approximately proportional to the soot consentration along the optical path. Laser induced scattering method was used to measure distribution of soot at two dimensional area. Also, it is compared exhaust characteristics of NOx and soot with results of optical measurement.

• 전기학회논문지P
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• 제53권2호
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• pp.77-81
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• 2004

In this paper, multi-functional measurement module for RTD and 4-20mA Analog input is presented. As you know, In many industry field, RTD has been used for measuring a temperature. Although It have good properties such as wide measurement range, accuracy, the hardware or software compensation methods were applied to better linearity in many applications. According to this paper, a simply approximation method and various measuring technique are proposed to compensate large lead's resistance influence in RTD temperature measurements. As the experiment and simulation results, it is proved that the proposed method has good performance of measuring temperature. Additionally, with the CAN based communication, remote monitoring and parameter setting functions are realized.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.637-643
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• 2022

Uranium and plutonium are required to be accounted in spent fuel head-end and major recovery area in pyro-process for safeguards purpose. The possibility of neutron resonance technique, as a nondestructive analysis, was simulated on isotopic fissile analysis for large scale process. Neutron resonance technique has advantage to distinguish uranium from plutonium directly in mixture. Simulation was performed on U235 and Pu239 assay in spent fuel and for scoping examination of assembly type. The resonance energies were determined for U235 and Pu239. The linearity in the neutron transmission was examined for the selected resonance energies. In addition, the limit for detection was examined by changing sample density, thickness and content for actual application. Several factors were proposed for neutron production and the moderated neutron source was simulated for effective and efficient transmission measurement. From the simulation results, neutron resonance technique is promising to analyze U235 and Pu239 for spent fuel assembly. An accurate fissile assay will contribute to an increased safeguards for the pyro-processing system and international credibility on the reuse of fissile materials in the fuel cycle.

• 융합신호처리학회논문지
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• 제2권2호
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• pp.28-38
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• 2001

교통정보는 크게 지점정보와 공간정보로 나눌 수 있다. 지점정보는 한 지점에서의 차량의 유무 판정을 통해 얻을 수 있는 정보이며, 공간정보는 일정 공간을 관찰해야만 얻을 수 있는 고급 교통정보이다. 영상처리를 이용해 공간정보를 측정하기 위해서는 차량의 전역 추적을 필요로 하는데 전역 추적에 기반한 영상검지기는 비디오 입력, 차량 탐지, 차량 추적, 교통정보 측정의 네 부분으로 나눌 수 있다. 기존의 연구들은 비디오 입력시 자동 아이리스를 사용하여 급격한 밝기변화에 대응치 못하는 단점이 있고 차량 탐지시 기존의 배경생성 방법들은 정체가 심한 교차로에서 매우 좋지 않은 결과를 보인다. 또한 대부분의 연구에서 교통정보 측정을 지점 정보로만 국한하였다. 본 연구에서는 자동 아이리스의 단점 개선을 위해 사용자 제어 아이리스 방법을 제안하였고, 복잡한 교차로에서도 배경생성을 견고히 할 수 있는 장면차이 기반 배경생성 방법을 제안하였다. 또한 통행량/시간/속도는 물론 대기행렬 길이, 회전/직진 교통류의 공간 교통정보를 측정하는 방법을 제안하였고 실제 실험을 해 본 결과 95%∼100%의 정확도를 보였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.775-780
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• 2008

This paper reports on the internal flow of a centrifugal mini pump working at the low flow rate operating conditions. The RNG $\kappa-\varepsilon$ turbulence model was employed to simulate the three-dimensional turbulent flow in the pump. To examine and certify the simulation results, a transparent acrylic centrifugal mini pump model which is suitable for PIV measurement has been developed. The tongue region and the passages region between blades were investigated using PIV. In order to eliminate the effect of refraction on the area closed to the wall and increase the measurement accuracy, the fluorescent particles were scatted into the working fluid with the tracing particles. It is found from the calculation and PIV measurement results that there is a large area of recirculation flow near the tongue at low flow rate operating conditions. The computationally predicted water head using the $\kappa-\varepsilon$ turbulence model at low flow rate operating conditions are in very good agreement with the experimentally measured water head and the mean velocity distributions at investigation area obtained by PIV and calculation showed a satisfactory agreement as well. Meanwhile, the results of PIV measurements show that the flow status in one passage is different to another. And for capturing the internal flow detail information, the $\kappa-\varepsilon$ turbulence model is not very suitable.

• 한국환경과학회지
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• 제12권7호
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• pp.705-713
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• 2003

In mid-August 2002, under clear summer pressure patterns, we carried out an intensive meteorological observation to examine the warming effects due to artificial constructions in a large housing complex. We set an automatic weather system(AWS) at two places in a bare soil surface within a limited development district and an asphalt surface within a large apartment residence area, respectively. As a result of observation, it became clear that the difference of the surface air(ground) temperature between the bare soil surface and its peripheral asphalt area reached about 4$^{\circ}C$(13$^{\circ}C$) at the maximum from diurnal variation of surface temperatures on AWS data. Through the heat balance analysis using measurement data, it became clear that the thermal conditions at two places are dependent on the properties of surface material. The latent heat flux over the bare soil surface reached to about 300 W/㎡, which is more than a half of net radiation during the daytime. On the other hand, it was nearly zero over the asphalt surface. Hence, the sensible heat flux over the asphalt surface was far more than that of the bare soil surface. The sensible heat flux over the asphalt surface showed about 20∼30 W/㎡ during the night. It was released from asphalt surface which have far more heat capacity than that of bare soil surface.

• 한국정밀공학회지
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• 제23권9호
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• pp.179-189
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• 2006

Recently the electrostatic 2-axis MEMS stages have been fabricated f3r the purpose of an application to PSD (Probe-based Storage Device). However, all of the components (platform, comb electrodes, springs, anchors, etc.) in those stages are placed in-plane so that they have low areal efficiencies such as a few percentage, which is undesirable as data storage devices. In this paper, we present a novel structure of an electrostatic 2-axis MEMS stage that is characterized by having a large areal efficiency of about 25%. For obtaining large area efficiency, the actuator part consisting of mainly comb electrodes and springs is placed right below the platform. The structure and operational principle of the MEMS stage are described, followed by a design and analysis, the fabrication and measurement results. Experimental results show that the driving ranges of the fabricated stage along the x and y axis were 27$\mu$m, 38$\mu$m at the supplied voltages of 65V, 70V, respectively and the natural frequencies along x and y axis were 180Hz, 310Hz, respectively. The total size of the stage is about 5.9$\times$6.8mm$^2$ and the platform size is about 2.7$\times$3.6mm$^2$.

• 한국수정란이식학회지
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• 제15권3호
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• pp.263-270
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• 2000

The ovaries of 178 Holstein heifers or cows (heifer; 41, 1 parity; 72, 2$\leq$ parity; 65) on Day 6 or 7 (Day 0=day of estrus) were examined by transrectal ultrasonography. Diameter of corpus luteum (CL) and large follicle ( $\geq$ 10 mm), and luteal tissue area were determined by ultrasound system with a 5 MHB rectal probe. Blood samples were taken to progesterone analysis. After selection of recipients, frozen Holstein embryos were thawed and directly transferred to recipients non-surgically. The diameter of CL and luteal tissue area was greater (P<0.01) on Day 7 than on Day 6 in heifers, 1 parity or 2 $\leq$ parity cows, respectively, although progesterone concentrations were not different. The presence of fluid-filled luteal cavitied or multiple CL (2 or more) did not affect serum progesterone concentration. A large follicles were observed in 67.4% of heifers or cows and the average diameter was 14.1 mm. Greater luteal tissue area attributed higher pregnancy in heifers, but not in cows, although there were no difference on pregnancy rate according to progesterone concentration in heifers or cows. The pregnancy rate of recipients contained a large follicle at embryo transfer was lower than that of recipients not contained. These results show ultrasonic assessment of ovaries in Holstein recipients is a reliable tool to determine the follicle and CL for recipient selection.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.521-524
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• 2005

In order to measure ECG in daily life, a new ECG measurement method on bed was developed. The provided method does not require any direct conductive contact between the instrument and bare skin, so that it does not cause the uncomfortable feel of touch and the possible skin trouble which are typical shortcomings of the conventional conductive contact ECG measurement. The provided method utilized an array of high-input-impedance active electrodes fixed on the mattress and an indirect-skin-contact ground made of a large conductive textile sheet and laid on lower area of the mattress. A thin cotton bedcover covered the mattress, the electrodes, and the conductive textile and subjects lay on the mattress over the bedcover. ECG was obtained successfully. However its signal quality is lower and the motion artifact is larger than direct-contact measurement. Careful measurement setup was needed to reduce the motion artifact originated from variation in static electricity. From the ECG obtained by the provided method, R-peak could be discriminated easily and the information about the position and the posture of the subject could be obtained.

• Journal of Computing Science and Engineering
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• 제11권3호
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• pp.79-91
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• 2017

In this paper, the abdominal-deformation measurement scheme is conducted on a shape-flexible mannequin using the DIC technique in a stereo-vision system. Firstly, during the integer-pixel displacement search, a novel fractal dimension based on an adaptive-ellipse subset area is developed to track an integer pixel between the reference and deformed images. Secondly, at the subpixel registration, a new mutual-learning adaptive particle swarm optimization (MLADPSO) algorithm is employed to locate the subpixel precisely. Dynamic adjustments of the particle flight velocities that are according to the deformation extent of each interest point are utilized for enhancing the accuracy of the subpixel registration. A test is performed on the abdominal-deformation measurement of the shape-flexible mannequin. The experiment results indicate that under the guarantee of its measurement accuracy without the cause of any loss, the time-consumption of the proposed scheme is significantly more efficient than that of the conventional method, particularly in the case of a large number of interest points.