• 반도체디스플레이기술학회지
• /
• 제8권1호
• /
• pp.27-31
• /
• 2009

A characteristic of new waveform, called a negative waveform, was studied during reset and address periods. IR distribution, black luminance and time delay were measured to compare the negative waveform with the conventional positive waveform. Based on the analysis of IR measurement, the negative waveform could accumulate more wall charges than the positive waveform. Also the black luminance of negative waveform was lower than that of positive waveform under the same bias and ramp-slope conditions. During address period, the discharge time lag was measured. The negative waveform was showed 0.25 us faster formative time lag and 0.1 us faster average time lag than those of positive waveform.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
• /
• pp.97-100
• /
• 2009

A negative waveform was studied to improve the driving characteristics of reset and address periods in ac PDP. Comparative experiments between negative and conventional positive waveforms were performed with 42-inch XGA PDP module. The negative waveform showed lower breakdown voltage than the conventional positive waveform in reset period. Due to its weak and stable discharge during reset period, the contrast ratio was improved by decreasing the black luminance. During address period, the discharge time-lag was measured. The formative time lag ($=T_f$) of negative waveform was improved about 22.8% than $T_f$ of conventional positive waveform.

• 센서학회지
• /
• 제22권1호
• /
• pp.38-43
• /
• 2013

In this study, the artery's compliance model and the pulsation waveform model was proposed to estimate blood pressure without applying HPF (High Pass Filter) on signal measured by the oscillometric method. The method proposed in the study considered two ways of estimating blood pressure. The first method of estimating blood pressure is by comparing and analyzing changes in pulsation waveform's dicrotic notch region during each cardiac period. The second method is by comparing and analyzing morphological changes in the pulsation waveform during each cardiac period, which occur in response to the change in pressure applied on the cuff. To implement these methods, we proposed the compliance model and the pulsation waveform model of the artery based on hemodynamic theory, and then conducted various simulations. The artery model presented in this study only took artery's compliance into account. Then, a pulsation waveform model was suggested, which uses characteristic changes in the pulsation waveform to estimate blood pressure. In addition, characteristic changes were observed in arterial volume by applying artery's pulsation waveform to the compliance model. The pulsation waveform model was suggested to estimate blood pressure using characteristic changes of the pulsation waveform in the arteries. This model was composed of the sum of sine waves and a Fourier's series in combination form up to 10th harmonics components of the sinusoidal waveform. Then characteristic of arterial volume change was observed by inputting pulsation waveform into the compliance model. The characteristic changes were also observed in the pulsation waveform by mapping the arterial volume change in accordance with applied cuff's pressure change to the pulsation waveform's change according to applied pressure changes by cuff. The systolic and diastolic blood pressures were estimated by applying positional change of pulsation waveform's dicrotic notch region.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.388-391
• /
• 2008

A new reset waveform with negative ramp pulse was proposed. Comparative experiments between the negative and positive waveforms were performed. During reset period, IR distributions and luminance of black and white conditions were measured with the 42-inch XGA PDP module. The negative waveform improved contrast ratio about 15.4 ~ 22.5 % than the positive waveform by lowing the black luminance in reset period. Z bias (= Vbb) of the positive waveform was 27 V higher than the negative waveform.

• 대한원격탐사학회지
• /
• 제26권6호
• /
• pp.681-691
• /
• 2010

LiDAR waveform decomposition plays an important role in LiDAR data processing since the resulting decomposed components are assumed to represent reflection surfaces within waveform footprints and the decomposition results ultimately affect the interpretation of LiDAR waveform data. Decomposing the waveform into a mixture of Gaussians involves two related problems; 1) determining the number of Gaussian components in the waveform, and 2) estimating the parameters of each Gaussian component of the mixture. Previous studies estimated the number of components in the mixture before the parameter optimization step, and it tended to suggest a larger number of components than is required due to the inherent noise embedded in the waveform data. In order to tackle these issues, a new LiDAR waveform decomposition algorithm based on the sequential approach has been proposed in this study and applied to the ICESat waveform data. Experimental results indicated that the proposed algorithm utilized a smaller number of components to decompose waveforms, while resulting IMP value is higher than the GLA14 products.

• 한국해양공학회지
• /
• 제6권1호
• /
• pp.122-130
• /
• 1992

The effect of loading waveform on elevated temperature low-cycle fatigue crack growth behavior in a SUS 304 stainless steel have been investigated under symmetrical trangular (fast-fast), trapezoidal and asymmetrical(fast-slow, slow-fast) waveforms at 650.deg. C. It was found that the crack growth rate in fast-slow loading waveform appeared to be higher a little and the crack growth rate in slow-fast loading waveform much higer than that in fast-fast loading waveform, and difference in crack growth rate between fast-show and slow-fast waveforms nearly didn't appear in the region of da/dN>10/sup -2/ The crack growth rate in the trapezoidal loading waveform with t/sub h/=500sec appeared to be faster than that in slow(500sec)-fast(1sec). In addition, parameter modified J-integral could be considered as useful parameter for fatigue crack growth rate in all waveforms. The result obtained are as follow. da/dN=4.91*10/sup -3/ (.DELTA. J/sub c/)/sup 0.565/.

• 한국측량학회지
• /
• 제29권3호
• /
• pp.257-263
• /
• 2011

기존의 LiDAR 데이터에 대한 정확도 검증, 적용성 검토, 변화탐지 등에 많은 연구 논문이 발표되었으나 주된 LiDAR 데이터의 형태는 discrete return LiDAR의 형태로 국한되어 full waveform LiDAR 데이터에 대한 연구는 미비한 상태이다. 따라서 본 연구에서는 full waveform LiDAR 데이터를 이용하여 연구대상 지역을 산림지역과 도심지역으로 현지 실측 측량 데이터를 이용하여 정확도를 비교 분석하였다. 그 결과 도심지역의 RMSE는 3.1cm, 산림지역의 RMSE는 4.7cm로 나타났으며, full waveform LiDAR의 고도 위치 정확도가 매우 높은 것으로 검증되었다. 항측 분야에서 full waveform LiDAR 장비의 활용가능성이 매우 높은 것으로 판단된다.

• 전기전자학회논문지
• /
• 제10권2호통권19호
• /
• pp.116-122
• /
• 2006

We have built a grating-based, high-resolution, spectral line-by-line pulse shaper. By controlling individual spectral lines of a mode-locked laser output, we demonstrate the interesting functionalities of the pulse shaper for arbitrary waveform generation, such as width tunable pulse generation, phase controlled waveform generation, microwave waveform generation, etc.

• 한국자동차공학회논문집
• /
• 제19권1호
• /
• pp.95-100
• /
• 2011

The test was done on cars travelling at speeds of 20km/h, 60km/h and 100km/h, the performance testing mode for chassis dynamometer. In this test, the secondary waveform were measured, including those using faulty MAP sensors, oxygen sensors and spark plugs. The results from these measurements and their analysis of secondary waveform can be summarized as follows: 1) The secondary waveform measured from the faulty oxygen sensor showed a lot of noise around peak voltage and in the rising and falling sections during spark line which means that the air fuel mixture was non-homogeneous. 2) The secondary waveform from the faulty MAP sensor showed the worst shape compared to other sensors, including variation of spark line, state of air-fuel mixture and velocity of flame front. 3) The spark line time of secondary waveform using a faulty spark plug displayed the shortest and smallest energy spark line, which means that a misfire occurred.

• Journal of the Optical Society of Korea
• /
• 제19권4호
• /
• pp.363-370
• /
• 2015

The current waveform model of a laser altimeter is based on a Gaussian laser beam of fundamental mode, while the flattened Gaussian beam has many advantages such as nearly constant energy distribution on the center of the cross-section. Following the theory of the flattened Gaussian beam and the waveform theory of the laser altimeter, some of the primary parameters of the received waveform were derived, and a laser altimetry waveform simulator and waveform processing software were programmed and improved under the circumstance of a flattened Gaussian beam. The result showed that the bias between theoretical and simulated waveforms was less than 3% for every order mode, the waveform width and range error would increase as target slope or order number rose. Under higher order mode, the shapes of the received waveforms were no longer Gaussian, and could be fitted more precisely as a generalized Gaussian function with power bigger than 2. The flattened beam got much better performance for a multi-surface target, especially when the small surface is far from the center of the laser footprint. This article provides the waveform theoretical basis for the use of a flattened Gaussian beam in a laser altimeter.