• Journal of Biomedical Engineering Research
• /
• v.31 no.4
• /
• pp.328-334
• /
• 2010

Over the past few years, a considerable number of methods have been proposed and applied for the classification of photoplethysmography (PPG). Most of the previous studies, however, focused on the qualitative description of the pulse type according to specific disease and thus provided ambiguous criteria to interpreters. In order to screen out this problem, we present a quantitative method for the pulse type classification including the second derivative of photoplethysmography (SDPTG). In the PPG signal, we have classified the signal as 4 types using the position and the presence of the dicrotic wave. In addition, we have categorized the SDPTG signal as 7 types using the position and the presence of "c" and "d" wave and the sign of "c" wave. In order to check the efficacy of the proposed pulse type classification rule, we collected pulse signals from 155 subjects with different ages and sex. From the correlation analysis, Class 1(p<0.01) and Class 2(p<0.01) in the PPG signal are significantly correlated with ages. In a similar manner Class A(p<0.01), Class C(p<0.05), Class D(p<0.01), and Class F(p<0.01) in the SDPTG signal are considerably correlated with the ages. From these observations, and some earlier ones [4], [5], we can conclude that since the newly proposed method has objectivity and clarity in pulse type classification, this method can be used as an alternative of previous classification rules including similar age-related characteristics.

• Proceedings of the KIPE Conference
• /
• 2007.11a
• /
• pp.43-46
• /
• 2007

In this paper, a novel new pulse power generator based on IGBT stacks is proposed for pulse power application. Proposed scheme consists of series connected 9 power stages to generate maximum 60kV output pulse and one series resonant power inverter to charge DC capacitor voltage. Each power stages are configured as 8 series connected power cells and each power cell generates up to 850VDC pulse. Finally pulse output voltage is applied using total 72 series connected IGBTs. The synchronization of gating signal is important for series operation of IGBTs. For gating signal synchronization, full bridge inverter and pulse transformer generates on-off signals of IGBT gating and specially designed gate power circuit was used. Proposed scheme has lots of advantages such as long lifecyle, compact size, flat topped pulse forming, small weight, protection for arc, high efficiency and flexibility to generate various kinds of pulse output.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.42 no.3
• /
• pp.649-660
• /
• 2017

In electronic warfare, the pulse amplitude, one of information of a pulse signal emitted by an enemy, is used for estimating distance from the source and for deinterleaving mixed source signals. An estimate of pulse amplitude is conventionally determined as the maximum magnitude of a Fourier transformed signal within its pulse width which is estimated pre-step in an electronic warfare receiver. However, when frequency modulated signals are received, it is difficult to estimate their pulse amplitudes with this conventional method because the energy of signals is dispersed in frequency domain. In order to overcome this limitation, this paper proposes an enhanced pulse amplitude estimation method which calculates the average power of the received pulse signal in time domain and removes the noise power of the receiver. Simulation results show that even in case the frequency modulated signal is received, the proposed method has the same performance as estimating the pulse amplitude when unmodulated signal is received. In addition, the proposed method is shown to be more robust to an estimation error of pulse width, which affects the estimation performance of pulse amplitude, than the conventional method.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.11
• /
• pp.1179-1182
• /
• 2011

RC servos are electro-mechanical devices that respond to a control signal, which instructs them to move their output shaft to a certain position. A servo is normally plugged into a radio receiver with a three pin connector. The three wires are a power (usually 4.8V to 6.0V), a ground, and a signal wire. The signal wire carries a PWM (Pulse-Width Modulation) signal consisting of a 1-2msec pulse repeated 50 times a second. A 1.5msec pulse will tell the servo to move to its output shaft to the center position, 0 degrees. For a servo with a 180 degree of motion, a 1msec pulse will move the servo to -90 degrees, and a 2msec pulse will move the servo to +90 degrees. In order to development a humanoid robot, mechanical design, fixtures design, analysis of kinematics, implementation moving program, selection of RC servo motor and controller are required. This study was performed to experimentally compare the rotation range of RC servo motors according to change of a periods.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.7
• /
• pp.85-91
• /
• 2016

Typically, radar systems change the pulse repetition interval of their modulated signal in order to avoid detection. On the other hand the radar-signal detection system tries to detect the modulation pattern. The histogram or auto-correlation methods are usually used to detect the PRI pattern of the radar signal. However these methods tend to lost the sequence information of the PRI pulses. This paper proposes a PRI-sequence detection algorithm based on the finite-state machine that could detect not only the PRI pattern but also their sequence.

• 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.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.9 no.3
• /
• pp.95-100
• /
• 2006

The pulse compression technique using Linear FM signal is commonly used for improving the performance of both the detection range and range resolution in radar system. In general, the compressed LFM waveform has relatively large sidelobe level which may prevent a target from being detected when strong jammer or clutter signal is near the target signal. In this paper, we propose a new weighting method which uses the square-root weight to suppress the sidelobe level. Typical applications are missile seekers and tracking radar systems where target tracking range is available prior to the signal processing. By computer simulation, we show that the performance of the proposed method is better than that of the conventional weighting methods in terms of sidelobe suppression.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.13 no.1
• /
• pp.140-146
• /
• 2010

The multi-function radar can detect and track the low RCS targets. For this purpose the multi-function radar uses the pulse train waveform. because this waveform has high dynamic range and good SNR(Signal to Noise Ratio). But the spurious signals can also be detected by processing the pulse train waveform. Thus the multi-function radar signal processor must have the high SFDR(Spurious Free Dynamic Range). This paper describes the development of the multi-function radar signal processor having the high SFDR.

• Journal of Biomedical Engineering Research
• /
• v.41 no.5
• /
• pp.185-194
• /
• 2020

Arrhythmia is basically diagnosed with the electrocardiogram (ECG) signal, however, ECG is difficult to measure and it requires expert help in analyzing the signal. On the other hand, the radial pulse can be measured with easy and uncomplicated way in daily life, and could be suitable bio-signal for the recent untact paradigm and extensible signal for diagnosis of Korean medicine based on pulse pattern. In this study, we developed an irregular radial pulse detection algorithm based on a learning model and considered its applicability as arrhythmia screening. A total of 1432 pulse waves including irregular pulse data were used in the experiment. Three data sets were prepared with minimal preprocessing to avoid the heuristic feature extraction. As classification algorithms, elastic net logistic regression, random forest, and extreme gradient boosting were applied to each data set and the irregular pulse detection performances were estimated using area under the receiver operating characteristic curve based on a 10-fold cross-validation. The extreme gradient boosting method showed the superior performance than others and found that the classification accuracy reached 99.7%. The results confirmed that the proposed algorithm could be used for arrhythmia screening. To make a fusion technology integrating western and Korean medicine, arrhythmia subtype classification from the perspective of Korean medicine will be needed for future research.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.49 no.8
• /
• pp.491-494
• /
• 2000

A scheme is proposed for measuring similarities between the binary pulse signals in the pulse-code modulation using the Integra-Normalizer. The Integra-Normalizer provides a better interpretation of the relationship between the pulse signals by removing redundant codes, which maps all possible observed signals to one of the codes to be received with relative similarities between each pair of compared signals. The proposed method provides better error tolerance than L2 metric, such as Hamming distance, since the distances between pulse signals are measured not useful for the time-delay detection in the pulse-code modulation.