• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.274-278
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• 2004

A simultaneous measurement system that can analyze the flaw-structure interactions has been developed This system consists of four CCD cameras, two for capturing instantaneous flaw fields and two for tracking a solid body. The three-dimensional vector fields around a cylinder are measured while the motion of the cylinder forced by the flow field is measured simultaneously with the constructed system The cylinder is pended in the working fluid of a water channel and the surface of the working fluid is forced sinusoidal to make the cylinder bounced Reynolds number for the mean main stream is about l000. The interaction between the flaw fields and the cylinder motion is examined quantitatively.

• Wind and Structures
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• 제4권5호
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• pp.441-454
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• 2001

Conical vortices on roof corners of a prismatic low-rise building have been investigated by using the PIV(Particle Image Velocimetry) technique. The Reynolds number based on the free stream velocity and model height was $5.3{\times}10^3$. Mean and instantaneous vector fields for velocity, vorticity, and turbulent kinetic energy were measured at two vertical planes and for two different flow angles of $30^{\circ}$ and $45^{\circ}$. The measurements provided a clear view of the complex flow structures on roof corners such as a pair of counter rotating conical vortices, secondary vortices, and tertiary vortices. They also enabled accurate and easy measurement of the size of vortices. Additionally, we could easily locate the centers of the vortices from the ensemble averaged velocity fields. It was observed that the flow angle of a $30^{\circ}$ produces a higher level of vorticity and turbulent kinetic energy in one of the pair of vortices than does the $45^{\circ}$ flow angle.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.862-866
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• 2004

Non-intrusive methods based on active remote IR illumination for eye tracking is important for many applications of vision-based man-machine interaction. One problem that has plagued those methods is their sensitivity to lighting condition change. This tends to significantly limit their scope of application. In this paper, we present a new real-time eye detection and tracking methodology that works under variable and realistic lighting conditions. Based on combining the bright-pupil effect resulted from IR light and the conventional appearance-based object recognition technique, our method can robustly track eyes when the pupils are not very bright due to significant external illumination interferences. The appearance model is incorporated in both eyes detection and tracking via the use of support vector machine and the mean shift tracking. Additional improvement is achieved from modifying the image acquisition apparatus including the illuminator and the camera.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2003년도 추계학술대회 논문집
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• pp.254-259
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• 2003

The Ejector is used to get low pressure, and it has been applied to a lot of industry field like the heat engine, the fluid instrument power plant, the food industry, environment industry etc... because there are not any problem even it is mixed with a any kind of liquid, gas, and solid. The flow characteristics in ejector are investigated by PIV and CFD. The experiment using PIV measurement for mixing pipe’s flow characteristics acquired velocity distribution, .Condition : when mixing pipe’s diameter ratio is 1:1.9, and the flux is $Q_{1}=1.136\;l/s$, $Q_{2}=1.706\;l/s$, $Q_{3}=2.276\;l/s$. Based on the PIV and the CFD results, the flow characteristics in ejector are discussed, and it shows the validity of this study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권1호
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• pp.53-76
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• 2020

The synchronous phasor measurement algorithm is the core content of the phasor measurement unit. This manuscript proposes a dynamic synchronous phasor measurement algorithm based on compressed sensing theory. First, a dynamic signal model based on the Taylor series was established. The dynamic power signal was preprocessed using a least mean square error adaptive filter to eliminate interference from noise and harmonic components. A Chirplet overcomplete dictionary was then designed to realize a sparse representation. A reduction of the signal dimension was next achieved using a Gaussian observation matrix. Finally, the improved orthogonal matching pursuit algorithm was used to realize the sparse decomposition of the signal to be detected, the amplitude and phase of the original power signal were estimated according to the best matching atomic parameters, and the total vector error index was used for an error evaluation. Chroma 61511 was used for the output of various signals, the simulation results of which show that the proposed algorithm cannot only effectively filter out interference signals, it also achieves a better dynamic response performance and stability compared with a traditional DFT algorithm and the improved DFT synchronous phasor measurement algorithm, and the phasor measurement accuracy of the signal is greatly improved. In practical applications, the hardware costs of the system can be further reduced.

• Asian Journal of Atmospheric Environment
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• 제10권2호
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• pp.80-89
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• 2016

In the complex terrain where local wind systems are formed, accurate understanding of regional wind variability is required for wind resource assessment. In this paper, cluster analysis based on the similarity of time-series wind vector was applied to classify wind regions with similar wind characteristics and the meteorological validity of regionalization method was evaluated. Wind regions in Jeju Island and Busan were classified using the wind resource map of Korea created by a mesoscale numerical weather prediction modeling. The evaluation was performed by comparing wind speed, wind direction, and wind variability of each wind region. Wind characteristics, such as mean wind speed and prevailing wind direction, in the same wind region were similar and wind characteristics in different wind regions were meteor-statistically distinct. It was able to identify a singular wind region at the top area of Mt. Halla using the inconsistency of wind direction variability. Furthermore, it was found that the regionalization results correspond with the topographic features of Jeju Island and Busan, showing the validity.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.429-434
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• 2002

The Synthetic Aperture Radar (SAR) data are considered to contain the greatest amount of information among various microwave techniques developed for measuring ocean variables from aircraft or satellites. They have the potential of measuring wavelength, wave direction and wave height of the ocean waves. But, it is difficult to retrieve significant ocean wave heights and surface current from conventional SAR data, since the imaging mechanism of ocean waves by a SAR is determined by the three basic modulation processes arise through the tilt modulation, hydrodynamic modulation and velocity bunching which are poorly known functions. Along-Track Interferometric (ATI) SAR systems can directly detect the Doppler shift associated with each pixel of a SAR image and have been used to estimate wave fields and surface currents. However, the Doppler shift is not simply proportional to the component of the mean surface current. It includes also contributions associated with the phase velocity of the Brags waves and orbital motions of all ocean waves that are longer than Brags waves. In this paper, we have developed a new method for extracting the surface current vector using multiple-frequency (L- & C-band) ATI SAR data, and have generated surface wave height information.

• International Journal of Industrial Entomology and Biomaterials
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• 제6권1호
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• pp.21-25
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• 2003

The implications of temperature $(25, 30 and 35{\times}1^{\circ}C)$ and relative humidity $(60, 70 and 80{\times}2%)$ on the moulting pattern, moulting duration and moulting survival were studied in the silkworm, Bombyx mori L. Larvae of two pure silkworm breeds, Pure Mysore (PM) and NB$_4$D$_2$and their hybrid, $PM{\times}NB_{4} D_{2}$ were reared under experimental conditions under natural day photoperiodic (LD 12:12) condition. Two developmental marker events in the fourth moulting, settling for moult (SM) and completion of moult (CM) occurred at or around the middle of the photophase. The computed mean vector (equation omitted), based on the circular statistics also confirmed the above. Temperature and humidity did not alter the moulting rhythmicity much. However, extreme temperature and humidity conditions reduced moulting survival in PM and $PM {\times}NB_{4} D_{2}$. Further, moulting survival reduced below the economic level in $NB_{4} D_{2}$. The temperature and humidity together seem to exert synergic impact on the moulting survival of the silkworm Bombyx mori, at least in $NB_{4} D_{2}$.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.4114-4114
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• 2001

For the quality control of tablets several parameters have to be checked. The most important one is the content of an active ingredient which has to match a narrow range around the designated content. The only useful measurement mode is transmission which provides information of the complete tablet. A measurement in diffuse reflectance would register only the surface which is useless especially in case of a coated tablet. In this work tablets for a clinical study (placebo/verum studies) with very low concentrations of the active ingredient were measured. The concentration range was 0 to 6 mg with a total weight of the tablets of 105 mg, leading to a highest concentration of the active component of 5.7% by weight. Especially the spectroscopic distinction between the placebo and the low dosage forms with 0.25 and 0.5 mg active agent requires an extraordinarily accurate sampling technique. Using the VECTOR 22/N-T in transmission mode allows the collection of the information from the complete tablets. A quantitative PLS-model with transmission spectra from the tablets described above shows that the active substance can be predicted with a RMSECV (root mean square error of cross validation) of 0.04% absolute for this special application. The results are compared with those of measurements in diffuse reflectance using different accessories.

• 한국정보통신학회논문지
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• 제9권1호
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• pp.152-159
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• 2005

본 논문에서는 스텝 크기(step size)를 자동적으로 조절함으로써 빠른 수렴비와 낮은 초과 MSE를 갖는 TS(Tagaki-Sugeno) 퍼지 모델과 ISI에 강하고 위상변화에 둔감한 CMA(constant modulus algorithm)를 접목시킨 새로운 퍼지 확률 기울기(Fuzzy Stochastic Gradient) 알고리즘을 제시하고 비이상적인 전송채널에 의해서 발생한 왜곡을 보상함으로써 수신 측에서 비트 검출 오류를 감소시키기 위하여 국내 지상파 디지털 TV의 표준으로 되어 있는 VSB 방식에 적용 가능한 등화기(equalizer)를 구현하였다.