• Korean Journal of Acupuncture
• /
• v.28 no.2
• /
• pp.13-22
• /
• 2011

Objectives : The purpose of this study is to investigate the effect of food intake on radial pulse amplitude. Methods : Thirty one healthy male subjects participated in this study. Radial pulse was measured using 3 dimensional pulse imaging system (DMP-3000) before, right after, 40 minutes after, 80 minutes after and 120 minutes after food intake. Results : 1. The amplitude of h1 increased significantly right after food intake compared to 'before food intake' at all 6 measuring points. Later on, it decreased back as time passed, however, even 120 minutes later, it was still higher than 'before food intake' 2. Pulse energy, which is calculated from pulse waves acquired with five sensors, increased after food intake as well. Conclusions : Food intake exerts an influence on radial pulse amplitude, resulting in increase of h1 and pulse energy.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.7
• /
• pp.1020-1026
• /
• 2013

Multirate filtering process on the biological signals like Electrocardiogram (ECG) and Photoplethysmogram (PPG) can be defined as the digital signal processing algorithm in which the sampling rate varies to omit or interpolate the intermediate values between the sampled data. With this aim, we suggest a new multirate filtering algorithm by deleting the extraneous data to eliminate the unwanted degradations such as granular noise due to the usage of high sampling frequency and simultaneously to detect the fiducial features of ECG and PPG with reducing the complexity of resolving fiducial points such as R-peak, Pulse peak and Pulse Transit Time (PTT). After the experimental simulations performed, we can conclude the fact that we can detect the fiducial features of ECG and PPG signal in terms of R-peak, Pulse peak and PTT without the loss of accuracy even if we do not maintain the original sampling frequency.

• Korean Journal of Optics and Photonics
• /
• v.24 no.2
• /
• pp.58-63
• /
• 2013

A theoretical analysis of the impact of rise time of a Q-switch on the output pulse performance is carried out in an Ytterbium-doped actively Q-switched fiber laser. The finite difference time domain (FDTD) method is used to numerically simulate the Q-switched fiber laser. It is shown that stable Gaussian-like pulse shape can be generated when the Q-switch rise time is increased and pulse repetition rate is enlarged.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.8
• /
• pp.1755-1760
• /
• 2013

In this paper, when the pulses propagate on a uniform microstrip line, the distortion of pulse signal caused by dispersion is investigated in time domain. We analyzed dispersion characteristics according to dielectric constant and structure of transmission line, and compared propagating characteristics for square and gaussian pulse according to pulse width, pulse amplitude, and propagation velocity. The results of this paper are compatible to the trade-off determination of relative permittivity, substrate height, strip width and pulse width of signal pulse when a design of MIC and MMIC is necessary.

• Journal of Mechanical Science and Technology
• /
• v.19 no.6
• /
• pp.1378-1389
• /
• 2005

This work provides the fundamental knowledge of energy transport characteristics during very short-pulse laser heating of semiconductors from a microscopic viewpoint. Based on the self-consistent hydrodynamic equations, in-situ interactions between carriers, optical phonons, and acoustic phonons are simulated to figure out energy transport mechanism during ultrafast pulse laser heating of a silicon substrate through the detailed information on the time and spatial evolutions of each temperature for carriers, longitudinal optical (LO) phonons, acoustic phonons. It is found that nonequilibrium between LO phonons and acoustic phonons should be considered for ultrafast pulse laser heating problem, two-peak structures become apparently present for the subpicosecond pulses because of the Auger heating. A substantial increase in carrier temperature is observed for lasers with a few picosecond pulse duration, whereas the temperature rise of acoustic and phonon temperatures is relatively small with decreasing laser pulse widths. A slight lagging behavior is observed due to the differences in relaxation times and heat capacities between two different phonons. Moreover, the laser fluence has a significant effect on the decaying rate of the Auger recombination.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.3
• /
• pp.167-171
• /
• 2014

This paper examines the destruction behavior of NPN BJT (bipolar junction transistor) by repetition pulse. The injected pulse has a rise time of 1 ns and the maximum peak voltage of 2 kV. Pulse was injected into the base of transistor. Transistor was destroyed, current flows even when the base power is turned off. Cause the destruction of the transistor is damaged by heat. Breakdown voltage of the transistor is 975 V at single pulse, and repetition pulse is 525~575 V. Pulse repetition rate increases, the DT (destruction threshold) is reduced. Pulse Repetition rate is high, level of transistor destruction is more serious.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.3
• /
• pp.395-400
• /
• 2013

In this paper, we introduce the implementation of high accurate level sensor system using the pulse wave type magnetostriction sensor. When a current pulse flows along the waveguide, the magnetic field also propagates towards the end of waveguide. When this magnetic field just passes the position of the magnet for level detection, the resultant magnetic field by these two magnetic fields makes a torsional reflected signal. This is used to calculate the time difference between a interrogation pulse wave and this torsional reflected signal. The key elements and characteristics were investigated to implement level sensor system based on this principle. We introduce a method to calculate the speed of ultrasonic reflected signal and how to make a model of sensing coil. In particular, we experiment with the characteristics of the torsional reflected signal according to the changes of the interrogation voltage and displacement. To make high accurate level sensor system, two methods were compared. One is to use the comparator and time counter, the other is STFT(Short Time FFT) which is capable of the time-frequency analysis.

• The Journal of Korean Medicine
• /
• v.32 no.4
• /
• pp.139-148
• /
• 2011

Objective: The purpose of this study was to investigate the effect of food intake on the Fourier components of radial pulse wave. Methods: Thirty-one healthy male subjects participated in this study. Radial pulse was measured using 3 dimensional pulse imaging system (DMP-3000) before, right after, 40 minutes after, 80 minutes after and 120 minutes after food intake. Fourier transform was performed and the frequency and amplitude of Fourier components were analyzed. Results: 1. The frequency and the amplitude of Fourier components of radial pulse wave increased significantly after food intake. 2. The frequency of Fourier components increased right after food intake and then gradually decreased as time passed, however the amplitude of Fourier components increased and maintained certain levels and patterns throughout the experimental period of 120 minutes. 3. The change ratios of the frequency and the amplitude of Fourier components after food intake varied with the pulse measuring locations. Conclusions: Food intake exerts an influence on radial pulse wave, resulting in increase of frequency and amplitude of Fourier components. The change ratios of the frequency and the amplitude of Fourier components after food intake varied with the pulse measuring locations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.04a
• /
• pp.139-142
• /
• 2000

Influence of frequency and duty ratio on electro-optical characteristics are experimentally investigated in surface AC plasma display panels(AC-PDPs) by using the VDS(Versitile Driving Simulator)., in which electrode gap and width are 100 ${\mu}m$ and 260 ${\mu}m$, respectively. The filling gas is Ne-Xe gas mixture, and total pressure 400 Torr. It is found that the response time gets to be fast from 450 ns to 150 ns as pulse-off time of the sustain pulse decreases from 2 ${\mu}s$ to 0.2 ${\mu}s$. Also it is found that the IR(Infra Red) intensity and the luminous decreases as pulse-off time of the sustain pulse increases from 0.2 ${\mu}s$ to 2 ${\mu}s$.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.14 no.1
• /
• pp.114-122
• /
• 2011

In this paper, we have identified the system instability factors in a bistatic radar system using pulse chasing and considered their effects on the bistatic receiver's MTI(Moving Target Indication) improvement performance. The pulse chasing is a method to efficiently scan a restricted search area within the limited transmitter power and time in a bistatic radar and to track a series of transmitted pulses using the receiver beam which has ideally matched to the pulse propagation rate. In this paper, we have discussed the interrelationship between the pulse chasing and time and frequency/phase synchronization and described the effects of the identified system instability factors on two kinds of MTI filter configuration, single delay-line and double delay-line, in the bistatic radar. And also, we have confirmed that the overall system improvement is restricted by a lower improvement factor among identified them, and discussed the allowable tolerance of the time and frequency/phase synchronization in the bistatic system.