• Journal of Korean Institute of Industrial Engineers
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• v.40 no.3
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• pp.325-332
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• 2014

High cognitive workload decreases a driver's ability of judgement and response in traffic situation and could result in a traffic accident. Electrocardiography (ECG) has been used for evaluation of drivers' cognitive workload; however, individual differences in ECG response corresponding to cognitive workload have not been fully considered. The present study developed an evaluation method of individual driver's cognitive workload based on ECG data, and evaluated its usefulness through an experiment in a driving simulator. The evaluation method developed by the present study determined the optimal ECG evaluation condition for individual participant by analysis of area under the receiver operating characteristic curve (AUC) for various conditions (total number of conditions = 144) in terms of four aspects (ECG measure, window span, update rate, and workload level). AUC analysis on the various conditions showed that the optimal ECG evaluation condition for each participant was significantly different. In addition, the optimal ECG evaluation condition could accurately detect changes in cognitive workload for 47% of the total participants (n = 15). The evaluation method proposed in the present study can be utilized in the evaluation of individual driver's cognitive workload for an intelligent vehicle.

• Journal of the Korean Society of Safety
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• v.30 no.2
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• pp.56-62
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• 2015

The purpose of this study was to identify the relationship between the index of Electrocardiography(LF/HF) and the occurrence of drowsiness driving while driving in a simulated situation. Participants were 31 undergraduate students with an experience in driving and they participated 30 minutes driving under enough sleep condition and 1 hour under the sleep deprivation condition. The Euro Truck Simulator II was used for driving simulation task and ECG and perceived drowsiness of each participants were measured during two driving conditions. Perceived sleepiness recorded by the checklist every 10 minutes and ECG data extracted before and after 15 seconds of every 10 minutes to verify the relationship between two variables. The results showed that the level of perceived sleepiness under sleep deprivation condition was higher than that under the enough sleep condition, and the level of LF/HF under sleep deprivation condition was lower than that under the enough sleep condition. In addition, the result of analysis of repeated measure ANOVA for ECG indicated that authentic sleepiness revealed in 20 minutes after the start of driving under the sleep deprivation condition. However, the result of perceived drowsiness indicated that authentic sleepiness revealed in 30 minutes after the start of driving. These result suggest that the time difference between biological and perceived response on drowsiness may be exist. Finally, the significant negative correlation between the LF/HF level and perceived drowsiness was observed. These findings suggest that ECG(LF/HF) can be an possible index to measure drowsiness driving.

• Journal of Biomedical Engineering Research
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• v.29 no.4
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• pp.295-301
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• 2008

A wireless 3 channel ECG monitoring system was developed so that it could monitor the health and movement state during subject's daily life. The developed system consists of a wireless biomedical signal acquisition device, a personal healthcare server, and a remote medical server. Three experiments were performed to evaluate the accuracy, reliability and operability, applicability during daily life of the developed device. First, ECG signals were measured using the developed device and commercial reference device during sitting and marking time and compared to verify the accuracy of R-R intervals. Second, the reliable data transmission to remote server was verified on two types of simulated emergency event using patient simulator. Third, during five types of motion in daily life, the accuracy of data transmission to remote server using CDMA network was verified on two types of event occurring. By acquiring and comparing subject's biomedical signal and motion signal, the accuracy, reliability and operability, applicability during daily life of the developed device were verified. In addition, PDA-phone based wireless system enabled subject to be monitored without any constraints. Therefore, the developed system is expected to be applicable for monitoring the aged and chronic diseased people and giving first-aid in emergency.

• Journal of Biomedical Engineering Research
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• v.12 no.2
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• pp.121-130
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• 1991

This paper presents a QRS recognition algorithm using attribute grammar and its interpreter. This system extracts primitive and their attributes by linear approximation technique and then represented linguistic formation using attribute grammar. These nonterminals and their attributes are evaluated by attribute grammar interpreter. The performance of the QRS recognition algorithm has been evaluated using arrhythmia simulator and CSE ECG library.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2217-2224
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• 2014

This paper deals with system development which measures 12 channel ECG using medical analog front end(AFE) and discriminates arrythmia through signal analysis. Recently, occurrences of cardiac arrest have been increased. So the need of system that diagnoses an arrythmia which results in cardiac arrest is increasing. There are some drawbacks of conventional 12 channel ECG system that it occupies bulk and consists of complicated circuit. To improve those, we made up the system composed of medical AFE, algorithm for discriminating arrythmia and DSP for signal processing. This system can be monitored 12 channel ECG waveforms and the discriminant analysis result of arrhythmia through 7" LCD and received the input through touch pannel. In this study, we conducted normal operation test about output signal of ECG simulator(normal/abnormal ECG signal) to verify the implemented system and performance evaluation of the optimization process for applying arrhythmia algorithm to an embedded environment.

• Science of Emotion and Sensibility
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• v.6 no.3
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• pp.13-20
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• 2003

In an experimental study, we assessed human sensibility in terms of psychophysiological response according to change of speeds (40, 70, 100km/h) in a driving simulator and application of motion fitters (washout filter, non-washout later) in a roller coaster simulator. For the driving and roller coaster simulators, a group of 12 healthy men in their twenties and a group of 8 healthy men in their twenties, respectively, participated. Participants each completed a simulator sickness questionnaire (SSQ), a subjective assessment of sensations of pleasantness, tension, and arousal, and perception of speed. Physiological signals were measured by 1/f fluctuation of EEG (electroencephalogram), ECG (electrocardiogram), and GSR (galvanic skin response). These were measured pre-to-post under the experimental conditions for each simulator. Subjective pleasantness, tension, arousal, and perception of speed and physiological responses indicating a feeling of pleasantness by 1/f fluctuation were higher for the roller coaster simulator than those measured for low speed driving in the driving simulator. The mean frequency of alpha band (8-l3㎐) in EEG increased with exposure to the driving simulator relative to that for the roller coaster simulator. Heart rate variability and GSR were significantly changed between pre- and post- under each condition in the driving and roller coaster simulators. The data suggest that subjective sensibility was elevated according to gain of speed and variety of simulator motion, and physiological responses were activated with increased speed.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.87-93
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• 2015

The accidents caused by drivers while driving are considered as the major causes along with other causes such as conditions of roads, weather and cars. In this study, we investigated the driver's workloads under three different driving conditions (Weather, Driving time zone, and Traffic density) through analyzing biological signals obtained from a car driving simulator system. The proposed method is able to detect R waves and R-R interval calculation in the ECG. Heart rate variability (HRV) was investigated for the time domain to determine the changes in driver's conditions.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.2
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• pp.111-117
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• 2019

We investigated the variations in the magnetic-field distribution and power transmission efficiency, resulting from changes in the relative positions of the transmitting and receiving coils, for electromagnetic-induction-type wireless power transmission using an elliptical receive coil. Results of simulations using a high-frequency structure simulator were compared to actual measurement results. The simulations showed that the transmission efficiency could be maintained relatively stable even if the alignment between the transmitting and receiving coils was changed to some extent. When the centre of the receiving coil was perfectly aligned with the centre of the transmitting coil, the transmission efficiency was the maximum; however, the degree of decrease in the transmission efficiency was small even if the centre of the receiving coil moved by ± 10mm from the centre of the transmitting coil. Therefore, it is expected that the performance of the wireless power transmission system will not be degraded significantly even if perfect alignment is not maintained. The results suggested a standardized application method of wireless transmission in the utilization of wireless power for implantable sensors.

• Korea Journal of Hospital Management
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• no.spc
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• pp.74-84
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• 2016

This research is for an innovative health information service cases based on Information Communication Technology (ICT), conducted at a general hospital in Korea. This study introduces a personal use self-diagnosis & self management device for pulmonary chronic disease patients, a mobile communication application service for doctor rounds, a surgical education system providing natural-user-interface with virtual reality for surgeons, and an Internet of things(IOT) technology using personal electrocardiogram (ECG) measurement device cases. Due to every case is on developing, there are still many issues needed to be improved. For this reason, various opinions with constructive critiques from the readers of this paper will be welcomed for better practical implementation.

• Science of Emotion and Sensibility
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• v.5 no.4
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• pp.51-57
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• 2002

The purpose of the study was to measure and compare driver's psychophysiological responses in different driving conditions through driving simulator. Twelve male adults(more than 1 year of driving experience) were assigned to four different driving conditions, such as normal speed(70㎞/h), sudden start(0㎞/h→70㎞/h), and sudden stop(70㎞/h→0㎞/h), and their simulator sickness, subjective pleasantness and arousal, EEG, ECG, skin temperature, and GSR were measured. Subjective and physiological evaluations were executed before and after driving in each condition. The results showed that subjective pleasantness and arousal increased in sudden stop and sudden start conditions, relative to stop and normal speed conditions. As the central nervous responses, beta wave increased and alpha wave decreased in sudden stop and sudden start conditions, relative to stop and normal speed conditions. With regard to the autonomic responses, heart rate and GSR increased, while skin temperature decreased in sudden stop and sudden start conditions, which means an activation of sympathetic nervous system. The results suggested that based upon observation of the distinctive psychophysiological changes by driving conditions, it is possible to evaluate the human sensibility in dynamic environment.