• Proceedings of the KIEE Conference
• /
• 1999.11c
• /
• pp.624-1-624-3
• /
• 1999

In this paper, complex demodulation method to access the dynamic autonomic nervous system characteristic of patients with syncope is proposed. Assessment of heart rate variability using conventional power spectral analysis such as FFT or AR-modeling could not capture a split change occurrence. However, in this paper, these changes are seen and by using Complex Demodulation Method(CDM) autonomic nervous system function assessments of patients with vasovagal syncope were verified and suggested.

• Science of Emotion and Sensibility
• /
• v.3 no.1
• /
• pp.1-6
• /
• 2000

단조 작업에 의한 정신적 피로도의 평가를 위하여 피험자에게 1자릿수 숫자 3개를 더하는 연산 작업을 수행하게 하였다. 주관적 평가를 통해 단조작업임이 확인된 task를 사용하여 작업 시간이 증가함에 따라 단조감이 증가하도록 실험과정을 설계하고 생리신호를 측정하였다. 측정된 생리신호 중 심전도, 피부온도, 호흡을 분석하였다. 단조 작업을 수행함에 따라 피부온도의 증가 경향이 나타났으며, 심박 변화율의 전력스펙트럽 분석결과 고주파성분의 감소와 Power spectrum balance가 증가하였다. 특히 power spectrum balance와 주관적 평가치의 상관관계가 높게 나타났다. 또한 상관관계가 높은 생리신호를 사용하여 정신피로를 예측한 결과 (R=0.945)가 정신피로를 잘 나타낼 수 있음을 알 수 있었다.

• Science of Emotion and Sensibility
• /
• v.3 no.2
• /
• pp.103-112
• /
• 2000

본 연구는 Graphic simulator에서 자동차 속도 변화에 따른 운전자의 감성변화를 주관적 평가와 자율신경계의 반응을 통해 알아보고자 한다. 속도 변화는 정차(0km/h), 40km/h, 100km/h, 160km/h로 제시하였고, 건강한 10명의 피험자를 대상으로 심박변화율, 피부저항, 피부온도, 맥파 등의 생리신호를 측정하였다. 본 연구 목적에 적절한 속도 관련 어휘를 추출하여 각 속도에서의 주관적 감성 변화를 평가하였다. 또한, 각 속도 실험 전 후에 Simulator Sickness를 측정하여 Simulator Sickness가 실험 결과에 미치는 영향을 분석하였다. 속도가 증가함에 따라 긴장도와 쾌도가 증가한다는 주관적 평가 결과를 얻었다. 실험 전에 비해 실험 후의 Simulator Sickness 값은 증가하였지만 실험 전, 후의 통계적 차이는 관찰할 수 없었다. 속도 증가에 따라, 평균 R-R간격, 피부온도의 진폭은 감소하였고, 피부저항은 증가하였고, 맥파의 평균 진폭은 감소하였다. 그러므로 본 연구를 통해 Simulator Sickness의 큰 영향 없이 Graphic Simulator에서 속도의 증가에 따라 교감신경계가 활성화됨을 관찰할 수 있었고, 이는 실제 동적 환경에서 속도 변화에 따른 자율신경계의 반응 및 주관적 평가 결과와 일치하는 것이다. 향후 복합 감각 자극이 가능한 시뮬레이터가 구축이 될 것이고, 이를 통해 보다 현실감 있는 동적 환경 제시와 감성 측정이 가능할 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.464-471
• /
• 2016

To investigate the effects of cardiac rehabilitation (CR) on cardiopulmonary exercise capacity in both elderly and younger patients with myocardial infarction (MI). Of the MI patients who received hospital-based CR between February 2012 and December 2015, we retrospectively reviewed the medical records of patients who continued a follow-up through the outpatient clinic. A total of 46 patients (18 elderly patients (${\geq}60years$) and 28 younger patient (< 60)) were included in this study. The subjects visited the clinic to perform aerobic exercises with ECG monitoring based on their initial exercise tolerance test outcome. The exercise capacity was measured by symptom-limited exercise tests before and after hospital-based CR. Before CR, the elderly group had a significantly lower exercise capacity in peak VO2, METs, anaerobic threshold, exercise time, respiratory exchange ratio (RER) than the younger group. After CR, elderly groups showed a significantly improved exercise capacity in exercise time, HRmax, HRrest, peak VO2, METs, anaerobic threshold, and RER. Both elderly and younger groups showed similar improvement of cardiopulmonary exercise capacity after hospital-based CR. There is a very low cardiac rehabilitation participation and referral rates with MI patients in Korea. It is considered necessary to further expand the participation of cardiac rehabilitation in elderly MI patients.

• Journal of Chest Surgery
• /
• v.30 no.12
• /
• pp.1205-1213
• /
• 1997

This study reviewed useful aspects of the intraoperative transesophageal echocardiography among the patients in whom heart surgery were undertaken between January 1996 and July 1996 at St.Pauls hospital, Medical College of Catholic University, Seoul, Korea. During that period, 61 patients were operated on because of valvular heart disease(25 patients), coronary artery disease(22 patients), congenital heart disease(13 patients), and combined coronary artery disease and valvular heart disease(1 patient). Two patients(1 redo-VSD and 1 valvular heart diease) needed repeated aortic cross clamping and complementary procedures because of incomplete initial procedures. There was no incidence of air embolism. We could observe significant relationship of cardiac output monitoring methods either by thermodilution technique and transesophageal echocardiography by linear regression analysis(p<0.001). We tested myocardial response(percentage of systolic wall thickness, PSWT) with low dose dobutamine challenge to predict post-CABG myocardial perfusion. And the test showed statistically significant resp.onse(sensitivity 76%, specificity 94.7%, positive predictive value 95%, negative predictive value 75%). These results suggest that cardiac surgeon could draw more benefits by intraoperative transesophageal echocardiography.

• Journal of the Korean Applied Science and Technology
• /
• v.40 no.3
• /
• pp.570-578
• /
• 2023

Experiments on zebrafish embryo toxicity and whitening efficacy, which is an alternative experimental animal model, were conducted using coffee by-products. As a result of the embryo toxicity test treated with the coffee residue extract, the coagulation rate was 3, 3, and 5% at 24, 48, and 72 hpf and concentration of 125 ppm, respectively. The hatching rate of embryos was 73% at the highest concentration of 125 ppm. In the heart beat rate experiment of zebrafish larva, the heart beat rate after 72 hpf was confirmed to be 153 times/60 s' at a concentration of 125 ppm. The negative control group showed no significant change in heart rate compared to the control group at 148 times/60s', and showed low toxicity. In addition, as a result of evaluating the whitening effect in zebrafish, melanin formation was inhibited as the concentration of the coffee residue extract increased. The results of this study suggest the possibility that naturally derived by-product materials can be used as raw materials for cosmetics, and are expected to be used in the cosmetics industry as an example of research that increases the added value of natural product residue.

• Science of Emotion and Sensibility
• /
• v.18 no.3
• /
• pp.63-70
• /
• 2015

This study identified heart response of participants while listening to sounds which have 1/f fluctuations with exponent ${\alpha}$ gradient. The participants were engaged in emotional stress work. Prior studies related to 1/f fluctuation sound have reported that sound source can alleviate psychological and physiological state of users. Subjects of this study were exposed to sound with three levels of ${\alpha}$ gradient. Heart response of subjects were measured with Photoplethysmography(PPG) sensor simultaneously. The dependent variables of this study were beat per minute(BPM), very low frequency percent of pulse rate variability (VLF percent), the standard deviation of all normal RR intervals (SDNN), and high frequency power(HF power). Subject showed arousal response when exposed to sound with exponent ${\alpha}$ gradient of 3 whereas the sound with exponent ${\alpha}$ gradient of 1 and 2 resulted in relax effect. The characteristic of 1/f fluctuation sounds can be applied to alleviate stress for employers under emotional labor.

• Journal of the Korean Society of Radiology
• /
• v.10 no.4
• /
• pp.285-290
• /
• 2016

The purpose of our study was to retrospectively evaluate the cause of a decreased calcium score of follow-up studies on coronary artery calcium scores (CACs) computed tomography (CT). The subjects were healthy 100 people(85 males $60.6{\pm}6.9$ years, 15 females $67.2{\pm}7.3$ years). The subjects decreased CACs were divided into 4 subgroups depending on Agatston classification, minimal (1-10), mild (11-100), moderate (101-400), severe (400<). As a result of decreased CACs were scan location disagreement 51%, motion artifact 26%, equipment changes 14%, operator mistakes 5%, input miss 2%, image loss 1%, arrhythmia 1%. In the mild group, the most common decreased CACs were 49 people. In the minimal group, the most significant variation reduction has occurred to 6 people. Scan location disagreement was considered a partial volume effects due to the scan starting position. It showed less than 100 CACs a high variation (19.7%) in more than 100 CACs, a lower variation (2.2%), these could be seen that the variation range is different that can be tolerated according to the calcification score. Motion artifact factor was found in 26%, which is so closely related to the preceding tests that affect the higher heart rate like this pulmonary function test, exercise stress test.

• Science of Emotion and Sensibility
• /
• v.14 no.4
• /
• pp.653-662
• /
• 2011

As technology in 3D industry has rapidly advanced, a lot of studies primarily focusing on visual function and cognition have become vigorous. However, studies on effect of 3D visual fatigue on autonomic nervous system have not less been conducted. Thus, this study was to identify and determine the effect that might have a negative influence on sympathetic nervous system, parasympathetic nervous system, and cardiovascular system. Fifteen undergraduates (female: 9, mean age: $22.53{\pm}2.55$) participated and were sat on a comfortable chair, viewing a 3D content during about 1 hour. Cardiac responses like SDNN(standard deviation of RR intervals), RMS-SD(root mean squared successive difference), and HF/LF ratios extracted from the measured PPG(Photo-PlethysmoGram) before viewing 3D were compared to those after viewing 3D. The results showed that after subjects watched the 3D, responses in sympathetic nervous system and parasympathetic nervous system were activated and deactivated, respectively relative to those before watching the 3D. The results showed that HF/LF ratio, Ln(LF), and Ln(HF) after viewing 3D were significantly reduced relative to those before viewing 3D. No significant effects were observed in SDNN and RMS-SD. Results obtained in this study showed that visual fatigue induced by watching 3D adversely influenced autonomic nervous system, and thereby reduced heart rate variability causing sympathetic nervous acceleration.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.2
• /
• pp.65-74
• /
• 2010

We propose a system that automatically recognizes the tense or relaxed condition of scrolling-shooting game subject that plays. Existing study compares the changed values of source of stimulation to the player by suggesting the source, and thus involves limitation in automatic classification. This study applies SOM of unsupervised learning for automatic classification and recognition of player's condition change. Application of SOM for automatic recognition of tense and relaxed condition is composed of two steps. First, ECG measurement and analysis, is to extract characteristic vector through HRV analysis by measuring ECG after having the player play the game. Secondly, SOM learning and recognition, is to classify and recognize the tense and relaxed conditions of player through SOM learning of the input vectors of heart beat signals that the characteristic extracted. Experiment results are divided into three groups. The first is HRV frequency change and the second the SOM learning results of heart beat signal. The third is the analysis of match rate to identify SOM learning performance. As a result of matching the LF/HF ratio of HRV frequency analysis to the distance of winner neuron of SOM based on 1.5, a match rate of 72% performance in average was shown.