• Journal of Biomedical Engineering Research
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• v.43 no.1
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• pp.27-34
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• 2022

Drunk driving defines a driver as unable to drive a vehicle safely due to drinking. To crack down on drunk driving, alcohol concentration evaluates through breathing and crack down on drinking using S-shaped courses. A method for assessing drunk driving without using BAC or BrAC is measurement via biosignal. Depending on the individual specificity of drinking, alcohol evaluation studies through various biosignals need to be conducted. In this study, we measure biosignals that are related to alcohol concentration, predict BrAC through SVM, and verify the effectiveness of the S-shaped course. Participants were 8 men who have a driving license. Subjects conducted a d2 test and a scenario evaluation of driving an S-shaped course when they attained BrAC's certain criteria. We utilized SVR to predict BrAC via biosignals. Statistical analysis used a one-way Anova test. Depending on the amount of drinking, there was a tendency to increase pupil size, HR, normLF, skin conductivity, body temperature, SE, and speed, while normHF tended to decrease. There was no apparent change in the respiratory rate and TN-E. The result of the D2 test tended to increase from 0.03% and decrease from 0.08%. Measured biosignals have enabled BrAC predictions using SVR models to obtain high Figs in primary and secondary cross-validations. In this study, we were able to predict BrAC through changes in biosignals and SVMs depending on alcohol concentration and verified the effectiveness of the S-shaped course drinking control method.

• Progress in Superconductivity and Cryogenics
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• v.17 no.4
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• pp.34-37
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• 2015

Developing Magnetoencephalography (MEG) based on Superconducting Quantum Interference Device (SQUID) facilitates to observe the human brain functions in non-invasively and high temporal and high spatial resolution. By using this MEG, we studied alpha rhythm (8-13 Hz) that is one of the most predominant spontaneous rhythm in human brain. The 8-13 Hz rhythm is observed in several sensory region in the brain. In visual related region of occipital, we call to alpha rhythm, and auditory related region of temporal call to tau rhythm, sensorimotor related region of parietal call to mu rhythm. These rhythms are decreased in task related region and increased in task irrelevant regions. This means that these rhythms play a pivotal role of inhibition in task irrelevant region. It may be helpful to attention to the task. In several literature about the alpha-band inhibition in multi-sensory modality experiment, they observed this effect in the occipital and somatosensory region. In this study, we hypothesized that we can also observe the alpha-band inhibition in the auditory cortex, mediated by the tau rhythm. Before that, we first investigated the existence of the alpha and tau rhythm in occipital and temporal region, respectively. To see these rhythms, we applied the visual and auditory stimulation, in turns, suppressed in task relevant regions, respectively.

• Progress in Superconductivity and Cryogenics
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• v.16 no.4
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• pp.44-48
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• 2014

A liquid nitrogen-cooled prepolarization ($B_p$) coil made for ultra-low field nuclear magnetic resonance and magnetic resonance imaging (ULF-MR) designed to generate 7 mT/A was fabricated. However, with suspected internal insulation failure, the coil was investigated in order to find out the source of the failure. This paper reports detailed build of the failed $B_p$ coil and a number of analysis methods utilized to figure out the source and the mode of failure. The analysis revealed that pyrolytic graphite sheet linings put on either sides of the coil for better thermal conduction acted as an electrical bridge between inner and outer layers of the coil to short out the coil whenever a moderately high voltage was applied across the coil. A simple model circuit simulation corroborated the analysis and further revealed that the failed insulation acted effectively as a damping resistor of $R_{d,eff}=6{\Omega}$ across the coil. This damping resistance produced a 50 ms-long voltage tail after the coil current was ramped down, making the coil not suitable for use in ULF-MR, which requires complete removal of magnetic field from $B_p$ coil within milliseconds.

• Journal of the Ergonomics Society of Korea
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• v.21 no.2
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• pp.59-70
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• 2002

This paper is about the evaluation of stress response and recovery using biosignals and fuzzy theory. We caused mental stress by means of a coin-stacking task. During the experiment, 4 kinds of biosignals, including frontalis EMG, ECG, peripheral skin temperature and skin conductance level, were acquired. Then, the degree of stress was assessed by synthetically those signals using fuzzy inference. From the fuzzy inference result, the parameters (amount of physiological change / amount of imposed stress) and (time to 25% recovery), which represent response and recovery respectively, were derived. We made a two-dimensional point graph using the response parameter as an abscissa and the recovery parameter as an ordinate for each subject.

• Journal of Biomedical Engineering Research
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• v.42 no.5
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• pp.211-224
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• 2021

Purpose: The purpose of this study is to present a way to alleviate motion sickness(MS) by stimulating acupoint through PEMFs, and to assess the effectiveness of PEMFs against stimulation previously used to stimulate acupoint using biosignal evaluations and surveys. Materials and Methods: Thirteen healthy men participated in the experiment. MS was induced in the participants, and MS relief stimulation was applied for 30 minutes. There were 4 types of MS relief stimulation, and Sham, Reliefband, Transcutaneous electrical nerve stimulation(TENS), and Pulsed electromagnetic fields stimulation(PEMFs) were used. The biosignals were measured during 30 minutes of applying MS relief stimulation, and the symptoms of MS were evaluated through a questionnaire survey. The measured biosignals are Electrocardiogram(ECG), Electrodermal activity(EDA), Respiration, Skin temperature(SKT), and Electrogastrogram(EGG). A one-way ANOVA test was performed for the rate of change by stimulation for MS relief over time. Results: Participants who were stimulated had a sharp decrease in MS symptoms. Biosignals were analyzed to evaluate autonomic nervous system activity, and the parasympathetic nervous system could be activated through stimulation. Conclusion: TENS and PEMFs were more effective in relieving MS symptoms than Reliefband. It is believed that PEMFs will be effective in consideration of the comfort of participants to be applied to actual vehicles, and studies to further verify the effects of PEMFs on MS should be conducted.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.213-220
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• 2014

Korean magnetoencephalography (MEG) system had been developed and installed to hospital. The Korean MEG system contains helmet-shaped arrays of 152 first-order double relaxation oscillation SQUID (DROS) sensor. As a clinical application we have measured and analyzed evoked responses in patients with functional brain disease by outer stimulation as follows; 1) auditory evoked field in patients with hemifacial spasm, 2) somatosensory evoked fields in patients with tumor. We confirm that neuromagnetic data by Korean MEG system can provide useful information for pre-surgical planning or functional brain research.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.04a
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• pp.171-175
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• 1998

This work presents an estimation for stress status using biosignal and fuzzy theory. Stress is estimated by 'coin-build' experiment with two type, relax and stress status. The estimator uses five biosignals, fuzzy logic to combine these signals and physiological knowledge. The system was tested in 10 records of healthy indivisuals and acheived a template of a stress progress. This work presents an estimation for stress status using biosignal and fuzzy theory. Stress is estimated by 'coin-build' experiment with two type, relax and stress status. The estimator uses five biosignals, fuzzy logic to combine these signals and physiological knowledge. The system was tested in 10 records of healthy indivisuals and acheived a template of a stress progress.

• Journal of Sensor Science and Technology
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• v.32 no.6
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• pp.378-385
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• 2023

Human biosignals provide essential information for diagnosing diseases such as dementia and Parkinson's disease. Owing to the shortcomings of current clinical assessments, noninvasive solutions are required. Machine learning (ML) on wearable sensor data is a promising method for the real-time monitoring and early detection of abnormalities. ML facilitates disease identification, severity measurement, and remote rehabilitation by providing continuous feedback. In the context of wearable sensor technology, ML involves training on observed data for tasks such as classification and regression with applications in clinical metrics. Although supervised ML presents challenges in clinical settings, unsupervised learning, which focuses on tasks such as cluster identification and anomaly detection, has emerged as a useful alternative. This review examines and discusses a variety of ML algorithms such as Support Vector Machines (SVM), Random Forests (RF), Decision Trees (DT), Neural Networks (NN), and Deep Learning for the analysis of complex clinical data.

• The Journal of Korean Medicine
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• v.28 no.2 s.70
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• pp.80-92
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• 2007

Objectives : Functional dyspepsia (FD) is one of the most common gastrointestinal diseases. Nevertheless, there are many unknown mechanisms of autonomic functioning in FD patients. This study was designed to investigate the relationship between FD and biosignals from heart rate variability (HRV) and Yangdorak diagnosis. Methods : 32 patients (22 female, 10 male; mean age 40) and 32 healthy volunteers (21 female, 11 malemean; age 38) participated in this study. First gastrointestinal symptoms rating scale (GSRS) was assessed by questionnaires in both groups to evaluate the types of gastrointestinal symptoms. Second, HRV and Yangdorak diagnosis were measured in both groups. Results : 1. The FD group in this study mainly had the complaint of 'bloating' symptoms. 2. There was statistically no significant difference between Yangdorak (total average and 24 acupoints) and HRV values except logarithmic low-frequency band (lnLF) and total power (TP) in frequency domain. 3. There was statistically no significant relationship between HRV and Yangdorak in either group. However, most Yangdorak values were positively related with some HRV values (low-frequency, low-frequency/high-frequency ratio and high-frequency, etc) in the control group. Conclusions : FD patients had relatively lesser sympathetic domain than healthy subjects, indicated by decreased lnLF and TP. Particularly, there were positive relationships and significant differences between Yangdorak and HRV in young healthy subjects. This suggests that biosignals from HRV may be a useful method that can differentiate FD from healthy state in those of young age.

• Science of Emotion and Sensibility
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• v.17 no.3
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• pp.95-106
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• 2014

This research analyzed biosignals associated with the change of emotion from lighting felt by the occupants and task type under various indoor thermal environments and illuminance, and examined the biosignals' impacts on work. To this end, the indoor thermal environment was constructed on the basis of PMV (predicted mean vote) index value, and various indoor environments were created by changing the brightness of LED stands. In this manner, a variety of indoor environments were constructed, and experiments were carried out. This research evaluates the sensibility response to lighting through a questionnaire survey in the given environment and incorporates different types of error searches. In this way, changes were analyzed by measuring electroencephalogram (EEG) and electrocardiograms (ECG). As a result, all biosignals on the task type showed significant differences from the thermal environment change. When PMV index value was 0.8 (temperature: $25^{\circ}C$, humidity: 50 %), concentration and attention were the most activated. However, the biosignals did not show significant differences from the illuminance change. Concentration on an occupant's work capability was confirmed to be closely related to the thermal environment. As for the subjective emotional response to lighting, the occupants felt comfort as illuminance was lower, while they felt discomfort as illuminance was higher. However, there were no significant differences from the thermal environment change.