• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1109-1115
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• 2008

In the ubiquitous health monitoring environments, it is quite important not only to evaluate the physiological health condition but also mental stress condition. In order to achieve this goal, a heart activity monitoring system utilizing a wearable bipolar electrode is devised and the heart rate variability(HRV) is extracted and interpreted in both frequency and time feature domains. Consequently, to evaluate the emotional stress condition of the subjects, a stress-induced experimental protocol was applied to healthy subjects and the time and frequency features of heart activity were analyzed in terms of the ratio of low frequency components v.s., high frequency components and the relevant the moving average distributions compromising the successive RR peaks intervals in the ambulatory ECG measurement system.

• Clinical and Experimental Pediatrics
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• v.52 no.7
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• pp.752-755
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• 2009

It is well known that hemodynamic load is one of the most important determinants of cardiac structure and function. Circadian variations in blood pressure (BP) are usually accompanied by consensual changes in peripheral resistance and/or cardiac output. In recent years, reduction in circadian variations in BP and, in particular, loss of nocturnal decline of BP were observed in hypertensive patients with left ventricular hypertrophy (LVH). The patients with only a slight or no loss of nocturnal decline of BP were considered "non-dippers". Regression of LVH was observed after prolonged antihypertensive therapy. Restoration of the circadian rhythm of BP was also observed. However, the classification of patients into "dippers" and "non-dippers" is arbitrary and poorly standardized and repeatable, and in the recent studies, most hypertensive patients with LVH were "dippers". Therefore, we should be particularly cautious about the conclusions drawn using this index. On the other hand, reduced activity of low-pressure cardiopulmonary baroreceptors and impaired day-to-night modulation of autonomic nervous system activity were observed in patients with only LVH. Therefore, alterations in cardiac structure may impair BP modulation. On the other hand, the reverse can also be trueprimary alterations in BP modulation, through a persistently elevated afterload, can increase cardiac mass. Thus, the interrelationship between cardiac structure and BP modulation is complex. Hence, new and more specific methods of evaluating circadian changes in BP are needed to better clarify the abovementioned reciprocal influences.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.251-260
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• 1998

The Holter monitoring system is a widely used noninvasive diagnostic tool for ambulatory patient who may be at risk from latent life-threatening cardiac abnormalities. In this paper, we design a high performance intelligent holter monitoring system which is characterized by the small-sized and the low-power consumption. The system hardware consists of one-chip microcontroller(68HC11E9), ECG preprocessing circuit, and flash memory card. ECG preprocessing circuit is made of ECG preamplifier with gain of 250, 500 and 1000, the bandpass filter with bandwidth of 0.05-100Hz, the auto-balancing circuit and the saturation-calibrating circuit to eliminate baseline wandering, ECG signal sampled at 240 samples/sec is converted to the digital signal. We use a linear recursive filter and preprocessing algorithm to detect the ECG parameters which are QRS complex, and Q-R-T points, ST-level, HR, QT interval. The long-term acquired ECG signals and diagnostic parameters are compressed by the MFan(Modified Fan) and the delta modulation method. To easily interface with the PC based analyzer program which is operated in DOS and Windows, the compressed data, that are compatible to FFS(flash file system) format, are stored at the flash memory card with SBF(symmetric block format).

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.379-381
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• 2005

Urodynamics describes a collection of tests designed to evaluate lower urinary tract function and can be performed using retrograde filling of the bladder within a room. In this study, we designed and calibrated the potable urodynamics monitoring system using DSP chip (TMS320VC33, Texas InstrumentTM, U.S.) and obtained signals of bladder(Pves) and bladder neck pressure(Pneck) and EMG using calibration kit (DPT9022K0122, MedtronicsTM, U.s,). This system monitor spontaneous urination during daily life and can make patients more comportable.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.834-837
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• 2005

In this paper, we describe the method of non-invasive blood pressure measurement using pulse wave transit time(PWTT). PWTT is a new parameter involved with a vascular that can indicate the change of BP. PWTT is measured by continuous monitoring of ECG and pulse wave. No additional sensors or modules are required. In many cases, the change of PWTT correlates with the change of BP. We measure pulse wave using the photo plethysmograph(PPG) sensor in an earlobe and we measure ECG using the ECG monitoring device our made in the chest. The measurement device for detecting pulse wave consists of infrared LED for transmitted light illumination, pin photodiode as light detector, amplifier and filter. We composed 0.5Hz high pass, 60Hz notch and 10Hz low pass filter. ECG measurement device consists of multiplexer, amplifier, filter, micro-controller and RF module. After amplification and filtering, ECG signal and pulse wave is fed through micro-controller. We performed the initial work towards the development of ambulatory BP monitoring system using PWTT. An earlobe is suitable place to measure PPG signal without the restraint in daily work. From the results, we can know that the dependence of PWTT on BP is almost linear and it is possible to monitoring an individual BP continuously after the individual calibration.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.703-706
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• 2007

The real-time monitoring about the activity of the human provides useful information about the activity quantity and an ability. This study developed a system for human physical activity assessment in ambulatory monitoring using portable sensing device combining a tri-axial accelerometer and wireless sensor node. This real-time system is able to identify several postures, posture transitions and movements with classification algorithm. In addition, this system also features fall detection capability. The results of the assessment for evaluating the performance of the system show high identification accuracy.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.4
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• pp.406-412
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• 2009

ECG is used on purpose to keep good health or monitor cardiac function of aged person as well as on purpose to diagnose the disease of heart patients. The ambulatory ECG monitoring system under guarantee of safety and accuracy is very efficient to prevent the progress of heart disease and sudden death. These systems can detect the temporary change of ECG that is very significant to diagnose heart disease such as myocardial ischemia, arrhyamia and cardiac infarction. In this paper, we describe the ECG signal analysis algorithm and measurement device for ECG monitoring. The authors designed a small-size portable ECG device that consisted of instrumentation amplifier, micro-controller, filter and RF module. The device measures ECG with four electrodes on the body and detects QRS complex and ST level change in realtime. Also it transmits the measured signals to the personal computer. The developed software for ECG analysis in personal computer has the function to detect the feature points and ST level changes.

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.49-57
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• 2022

Objective: This study aims to conduct a comprehensive review of monitoring systems to monitor and manage physical function of community-dwelling elderly living alone and suggest future directions of unobtrusive monitoring. Design: Literature review Methods: The importance of health-related monitoring has been emphasized due to the aging population and novel corona virus (COVID-19) outbreak.As the population gets old and because of changes in culture, the number of single-person households among the elderly is expected to continue to increase. Elders are staying home longer and their physical function may decline rapidly,which can be a disturbing factorto successful aging.Therefore, systematic elderly management must be considered. Results: Frequently used technologies to monitor elders at home included red, green, blue (RGB) camera, accelerometer, passive infrared (PIR) sensor, wearable devices, and depth camera. Of them all, considering privacy concerns and easy-to-use features for elders, depth camera possibly can be a technology to be adapted at homes to unobtrusively monitor physical function of elderly living alone.The depth camera has been used to evaluate physical functions during rehabilitation and proven its efficiency. Conclusions: Therefore, physical monitoring system that is unobtrusive should be studied and developed in the future to monitor physical function of community-dwelling elderly living alone for the aging population.

• Journal of Electrical Engineering and Technology
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• v.8 no.2
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• pp.376-384
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• 2013

With the continuous aging of the populations in developed countries, the medical requirements of the aged are expected to increase. In this paper, a ring-type pulse oximeter finger sensor and a 24-hour ambulatory heart rate monitoring system for the aged are presented. We also demonstrate the feasibility of extracting accurate heart rate variability measurements from photoelectric plethysmography signals gathered using a ring-type pulse oximeter sensor attached to the finger. We designed the heart rate sensor using a CPU with built-in ZigBee stack for simplicity and low power consumption. We also analyzed the various distorted signals caused by motion artifacts using a FFT, and designed an algorithm using a least squares estimator to calibrate the signals for better accuracy.

• Journal of Digital Contents Society
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• v.9 no.4
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• pp.601-606
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• 2008

U-Healthcare is one of the major applications in ubiquitous sensor network. U-Healthcare has potential to become a critical service for the people who immediately require emergency ambulatory attention. This paper describes about the real time pulse monitoring and reporting system, consisting of two components: thus, the one is a reliable bio-sensor that continuously monitors the pulse information of the subject, and the other is the automatic transfer system that transmits pulse information to both his/her family and hospital care system through the Base Station. In the hospital, this bio-information can be used to treat the patient accordingly. I designed the pulse information monitored by a bio-sensor module that transfers the pulse information to both the Base Station and the central monitoring system through transmitting protocols such as Zigbee and TCP/IP, as well as designed the architecture of information packets for the corresponding protocols. Furthermore, the central monitoring system automatically parses the pulse information of the subject into the web database server, which can continuously provides the real time information and status of the subject via an internet browser to the clients who are family members of the subject and the authenticated medical care personnel as well.