• Title/Summary/Keyword: Amplitude Ratio

검색결과 966건 처리시간 0.033초

A Study on the Dynamic Bending Properties of Textile Fabrics

  • Kim, Jong-Jun
    • 패션비즈니스
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    • 제15권3호
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    • pp.84-96
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    • 2011
  • With the advancements in the computer graphics sectors, the visual quality of the virtual clothing implemented by using the 3-dimensional digital clothing software system has been much improved during the past decade. Most of the cloth simulation procedures are complicated due to the multitude of parameters involved in the simulation in order to achieve the appearance of the actual textile fabrics or the movement of the actual clothing as close as possible. Bending properties affect the tactile and visual qualities of the textile fabrics along with the shear and tensile properties. In this study, dynamic bending properties, focused on the movement of the textile fabrics including damping ratio and amplitude, were measured by using a dynamic bending test system.

컴퓨터 시각에 의한 사과 결점 검출 (Detection of Apple Defects Using Machine Vision)

  • 서상룡;성제훈
    • Journal of Biosystems Engineering
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    • 제22권2호
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    • pp.217-226
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    • 1997
  • This study was to develop a machine vision system to detect and to discriminate 5 kinds of apple surface defectbruise, decay. fleck, worm hole and scar. To detect the defects from an image of apple, thresholding technique was applied to images on various frames (R, G, B, H, S and I) of the color machine vision and an image of near infrared (NIR). To discriminate the detected region of defect, various features of the 5 kind defect regions were extracted from the 4 kinds of images selected above. The features were size of area, roundness, axes length ratio, mean and valiance of pixel values, standard deviation of real part of amplitude spectrum in frequency domain obtained by Fourier transform of pixel data and mean and standard deviation of power spectrum obtained by the same transform of pixel data. Routines to discriminate the defects from the features of image were developed and tested to prove their validity. The test resulted that I-frame and NIR images were the most desirable. Accuracies of the two images to discriminate the defects were noted as 76% and 77%, respectively.

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Determination of Total Glycyrrhetic Acid in Glycyrrhizae Radix by Second Derivative UV Spectrometry

  • Song, Seung-Bae;Choi, Jung-Kap;Yoo, Gyurng-Soo
    • Archives of Pharmacal Research
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    • 제13권2호
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    • pp.174-179
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    • 1990
  • Second derivative (D2) spectrometry using ion-pair extraction technique was development for the determination of total glycyrrhetic acid (GA) in Glycyrrhizae Radix, Glycyr-rhizin (G) obtained from Glycyrrhizae Radix was hydrolyzed into GA in 2 N-HCI and methanol (1:1) and extracted from aqueous phase in the form of an ion-pair complex with tetrapentylammonium bromide (TPA) as a counter ion. Maximum D2 amplitude (Z value) was obtained when 1000-fold or greater molar ratio of TPA was used at pH 11. Reaction an effective extraction solvent of the ion-pair complex. The linearity of standard curve of ion-pair GA was obtained in the range of 4.120 $\mu$g/ml as GA. Assayed contents of GA in dry powder by D2 UV spectrometry and HPLC method were 5.31 $\pm$ 0.04% and 5.20 $\pm$ 0.008%, respectively.

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Statistical Analysis of Fluorescence Correlation Spectroscopy of Ultra Low Concentration Molecules with a Confocal Microscope

  • Lee, Soon-Hyouk;Lim, Gyu-Chang;Kim, Soo-Yong;Kim, Eun-Kyung;Kim, Hak-Sung;Kim, Sok-Won
    • Journal of the Optical Society of Korea
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    • 제12권3호
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    • pp.170-173
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    • 2008
  • In this study, we simulated a statistical model of FCS(fluorescence correlation spectroscopy) based on a Poisson process to understand and explain observations of the experiment performed on molecules of ultra-low concentration by the home-built laser-scanning confocal microscope. The statistical model confirmed that the relative mean square amplitude of fluctuations is shown to be inversely proportional to the average number of molecules, even in the ultra-low concentration, if some conditions are satisfied. Signal-to-noise ratio and the variability of dwelling time under the confocal volume were found to be effective conditions for the experiment.

Abnormality of GCR intensities measured by ground NMs in solar minimum of solar cycles 23/24

  • Lee, Eo-Jin;Yi, Yu
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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    • pp.26.1-26.1
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    • 2009
  • Many solar, interplanetary and geomagnetic activity parameters have 11-year cycle on the average in sync with solar sunspot number. The galactic cosmic ray (GCR) intensity measured by ground Neutron Monitor (NM) is one of those parameters showing the unprecedented activity levels in the current solar minimum (2008-2009) of solar cycles 23/24. We defined abnormality as the ratio of deviation from long term mean over mean amplitude of solar cycle change. The abnormality distribution map was drawn using all the data of NM stations available online. The implications of those unprecedented levels of GCR intensities of different cutoff rigidities will be discussed.

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철근콘크리트 슬래브의 고유진동수 추정 (Estimation of Natural Frequency of Reinforced Concrete Slab)

  • 우운택
    • 한국구조물진단유지관리공학회 논문집
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    • 제4권4호
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    • pp.219-223
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    • 2000
  • The evaluation of habitability to building vibration is conducted by the values of natural frequency, amplitude displacement, damping ratio. These values can be obtained from test or analytical results. Data acquisition through test may be possible in existing building, however, to estimate the serviceability of the building, it is necessary to evaluate those values at the stage of design. The natural frequency is important and basic factor for the evaluation of the serviceability. Calculation method of the effective stiffness in RC slab is proposed. To prove the efficiency of the proposed method, sample results of the analysis and the test are compared. These results proved that the effective width proposed to calculate the effective stiffness is proper to evaluate the natural frequency.

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전자석을 이용한 가제어형 스퀴즈필름댐퍼 (Controllable Squeeze Film Damper Using an Electromagnet)

  • 안영공;하종룡;양보석;김동조
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.510-513
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    • 2003
  • The paper represents the stability of a rotor system with the squeeze film damper (SFD) using an electromagnet. The electromagnet is installed in the inner damper of the SFD. The proposed SFD has basically property of a conventional SFD and variable damping property according to variation of the applied electric current. Therefore, when the applied current controlled, the whirling vibration of the rotor system can be effectively reduced in a wide operational speed range. In the present work, the performance of the SFD was experimentally investigated according to changing the magnetic field strength. When the applied current increased, the whirling amplitude greatly reduced and the damping ratio also increased.

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프로브 마이크로폰을 사용한 귓속형 보청기 성능 검사장치 개발 (ITE Hearing Aid Specification Testing Devise Development using Probe Microphones)

  • 장순석;권유정
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.1044-1047
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    • 2003
  • An acoustic testing device composed of 2 probe microphones was developed for the electro-acoustic specification testing of the ITE (In-The-Ear) hearing aid (HA). The amplitude ratio and the phase difference between the incident pressure onto the HA microphone and the outward pressure of the HA receiver were measured by the present acoustic system. The microphones were particularly used because of small acoustic cavities where input and output pressures were present. The acoustic wall composed of clay completely blocks the propagation of the sound pressure between the small acoustic cavities. The system has an advantage of structural flexibility for the acoustic testing of different sizes and shapes of ITE-type HAs.

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자기장을 사용한 원형주상체 주위의 유동 제어 및 저항감소 (Flow Control and Drag Reduction of a Circular Cylinder by an External Magnetic Field)

  • 윤현식;전호환
    • 대한조선학회논문집
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    • 제41권2호
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    • pp.70-78
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    • 2004
  • The present study numerically investigates two-dimensional laminar flow past a circular cylinder in an aligned magnetic field using the spectral method. Numerical simulations are performed for flow fields with Re=100 and 200 in the range of 0$\leq$N$\leq$10, where Ν is the Stuart number that is the ratio of electromagnetic force to inertial force. The present study reports the detailed information of flow quantities on the cylinder surface at different Stuart numbers. It is shown that the vortex shedding can be controlled by the magnetic force representing the Stuart number. As Ν increases, the vortex shedding becomes weaker, resulting in drag reduction whose magnitude is the largest at a critical value. In addition, as the magnetic force increases, the lift amplitude decreases, reaching zero at the critical number.

MPE-LPC를 이용한 심전도 신호의 압축 (Compression of Electrocardiogram Using MPE-LPC)

  • 이태진;김원기;차일환;윤대희
    • 전자공학회논문지B
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    • 제28B권11호
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    • pp.866-875
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    • 1991
  • In this paper, multi pulse excited-linear predictive coding (MPE-LPC), where the correlation eliminated residual signal is modeled by a few pules, is shown to be effective for the compression of electrocardiogram (ECG) data, and a more efficient scheme for a faithful reconstruction of ECG is proposed. The reconstruction charateristic of QRS's and P.T waves is improved using the adaptive pulse allocation (APA), and the compression ratio (CR) can be changed by controlling the mumber of modeling pulses. The performance of the proposed method was evaluated using 10 normal and 10 abnormal ECG data. The proposed method had a better performance than the variable threshold amplitude zone time epoch coding (AZTEC) algorithm and the scan-along polygonal approximation (SAPA) algorithm with the same CR. With the CR in kthe range of 8:1 to 14:1, we could compress ECG data efficiently.

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