• Journal of Biomedical Engineering Research
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• v.29 no.6
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• pp.443-450
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• 2008

The purpose of this study is to measure both ECG and BCG(Ballistocariograph) signal of a subject on moving or resting wheelchair and detect the heart rate and respiratory rate and transmit an event message to remote server on emergent situation. To acquire ECG and BCG data, amplifier circuits were composed to be suitable for their characteristics. The output signals were converted to digital data and stored in bio-signal archiving media(SD card). CDMA module was used to transmit the event data on ECG electrode detachment and the received data was monitored by the developed C# application program. 5 volunteers participated in the experiment to evaluate the validity of the developed device. When the event occurs in each subject, 48 Kbyte data, stored for 32 seconds from that point, was transmitted to remote server through CDMA cellular phone network correctly. The received data of ECG, BCG, and 3-axial acceleration could be archived in server and the heart rate and respiratory rate could be measured and analyzed. The developed device in this study could acquire the ECG and BCG data of subjects on wheelchair simultaneously and measure their heart rate and respiratory rate. In addition, event data was verified to be transmitted to remote server without any errors.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.85-89
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• 2014

Electrocardiogram (ECG) is a diagnostic test which records the electrical activity of the heart, shows abnormal rhythms and detects heart muscle damages. With this ECG signal, medical centers diagnose patients' heart disease symptoms. A normal resting heart rate for adults rages from 60 to 100 beats a minute. An irregular heartbeat is called "arrhythmia", and arrhythmia is also called "cardiac dysrhythmia". In an arrhythmia, the heartbeat maybe too slow(slower than 60beats), too rapid(faster than 100beats), too irregular, etc. Among these symptoms of arrhythmia, if the heart beat is slower than the normal range, the symptom is called "bradycardia", and if it is faster than the range, it is called "tachycardia" In this letters, we proposed the detection algorithm of cardiac arrhythmia in ECG signal using R-R interval through the detection of R-peak.

• Journal of Biomedical Engineering Research
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• v.29 no.3
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• pp.191-197
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• 2008

This research focused on the development of wireless telemetry system that can monitor heart rates of multiple rehabilitation patients in real time without constraint. The whole system consists of the multiple patient's side devices (PSDs) and one central monitoring system (CMS). The PSD consists of a microphone, amplifier, filter, microcontroller, and RF (Radio Frequency) modem. In addition, the PSD was designed to be wearable and low power consumption. The CMS consists of an RF modem and general PC and it was designed to monitor heart rates from multiple patients simultaneously. The system warns an alarm signal when a patient's heart rate exceeds the pre-set range for each patient. This system can be useful to monitor the heart rate of exercising rehabilitation patients and control the patients condition and the exercising level.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.2
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• pp.105-120
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• 2010

Objectives : This study aims to evaluate the effects of expiration-to-inspiration time ratio (E/I-ratio) on heart rate, which represents cardiac autonomic function, and cold-heat in the healthy people. Methods : 49 healthy young volunteers(male : female = 32 : 17) were recruited in the study. The participants completed the questionnaire for yin-yang pattern identification and then we measured the chest plethysmogram for respiration signal and the electrocardiogram for NN intervals during different E/I-ratio from 1 to 2. We compared heart rate variability including RMS-SD, VLF, LF and HF, and the trend-cycle factors decomposed from NN interval data by time series analysis among the respective E/I-ratio. We also confirmed the difference on the trend-cycle factors according to the score of the questionnaire for cold and heat pattern identification. Results : There were differences on the trend-cycle factors from NN interval data, but no significant difference on heart rate variability, among the respective E/I-ratio. We also found significant relationship between the trend-cycle factors and the heat pattern identification scores. Conclusions : The results indicate that cardiac autonomic function can be modulated by the E/I-ratio and the modulation will be slower and more tendencious than respiratory sinus arrhythmia.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.3
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• pp.136-142
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• 2014

Distinct features in heart rate signals during the driver's wake and sleep states could provide an initiative for the development of a safe driving systems such as drowsiness detecting sensor in a smart wheel. We measured ECG from health subjects ($23.5{\pm}2.5$ in age) during the wake and drowsiness states. The proposed method is able to detect R waves and R-R interval calculation in the ECG even when the signal includes in abnormal signals. Heart rate variability(HRV) was investigated for the time domain and frequency domains. The STD HR(0.029), NN50(0.044) and VLF power(0.0018) of the RR interval series of the subjects were significantly different from those of the control group (p < 0.05). In conclusion, there are changes in heart rate from wake to drowsiness that are potentially to be detected. The results in our study could be useful for the development of drowsiness detection sensors for effective real-time monitoring.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.6
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• pp.75-81
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• 2010

The purpose of this study was to investigate the short-term effects of electrical massager on stress-related parameters including heart rate variability (HRV), heart rate (HR) using the photoplethysmogram (PPG) signal with motion artifact correction. Twenty healthy subjects were randomly allocated to receive a 15-min section of three types ((1) resting mode (control group), (2) light massage mode, (3) strong massage mode). Results indicated that self-report, VAS (Visual Analog Scale) significantly decreased for two massage modes after massage except control group. In strong massage mode, it was associated with significant increases in HF, but significant decreases in LF and LH/HF ratio compared with the light massage mode. For all outcomes, similar changes were not observed in the control group. Also, the result founded that mean HR of all groups decrease. We conclude that electrical massager reduces perceived stress and improves adaptive autonomic response to stress in healthy adults.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.320-324
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• 1996

Digital fetal monitoring system based on the personal computer combined with the digital signal processing board was implemented. The DSP board acquires and digitally processes ultrasound fetal Doppler signal for digital rectification, FIR filtering, autocorrelation function calculation, its peak detection and MEDIAN filtering. The personal computer interfaced with the DSP board is in charge of graphic display, hardcopy, data transmission and on-line analysis of fetal heart rate change including and variability. I used a recursive technique for autocorrelation function computation method and MEDIAN filter which can greatly reduce the amount of calculation and accuracy. I also implemented analysis algorithm of fetal heart rate change based on normal fetal sample data in order to exact diagnosis.

• Journal of electromagnetic engineering and science
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• v.3 no.1
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• pp.45-49
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• 2003

Wireless life signal detecting system is implemented with using the mechanism of Doppler Effect. This system can measure the respiration and heart rates with the periodic movement of skin and muscle near the heart. The system is consisted of antenna, RF transmitter, receiver, and display part. We did use two operating frequencies at 1.9 ㎓ and 10 ㎓. Firstly, the link budget about detecting system is analyzed and the signal detected from the system is compared with electrocardiogram(ECG) of monitor which is using for patient monitoring in hospital. Secondly, the detection of vital sign is also performed according to the different distances, and including behind the wall.

• Journal of Biomedical Engineering Research
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• v.36 no.5
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• pp.143-149
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• 2015

In this paper, we proposed a novel method for automatic detection for snoring and heart beat using a single piezoelectric sensor. For this study multi-rate signal processing technique was applied to detect snoring and heart beat from the single source signal. The sound event duration and intensity features were used to snore detection and heart beat was found by autocorrelation. The performance of the proposed method was evaluated on clinical database, which is the nocturnal piezoelectric snoring data of 30 patients that suffered obstructive sleep apnea. The method achieved sensitivity of 88.6%, specificity of 96.1% with accuracy of 95.6% for snoring and sensitivity of 94.1% and positive predictive value of 87.6% for heart beat, respectively. These results suggest that the proposed method can be a useful tool in sleep monitoring and sleep disordered breathing diagnosis.

• Journal of the Korea Society of Computer and Information
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• v.22 no.6
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• pp.87-93
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• 2017

In this paper, we design a small low power single channel ECG(Electrocardiogram) system of Chest Belt type with fiber-type electrodes to measure emotional state change of game addict. HRV(Heart Rate Variability) is analyzed through heart rate signal measurement and the psychological stress state is judged by using it. And it verifies its effectiveness through prototype. First, we design HR measurement module through low power MCU(Micro Controller Unit) and implement prototype level measurement system. The results showed that the difference between the addiction group and the general group was confirmed and that the system was effective. The result of this study can be used for health management such as reduction of stress of the user through music and breathing that lowers the stress by detecting the stress state of the general person or the chronic ill person.