• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.142-152
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• 2019

This study aimed to explore the association between obesity index and heart rate variability (HRV) in college-aged male smokers. A total of 85 male college students (> 10 cigarettes per day for at least 3 years) were participated in this study. According to a standardized protocol, body mass index (BMI), percent body fat (%BF), waist circumference (WC), and waist-to-hip ratio (WHR) were taken as obesity indices. Resting r-r interval was monitored for HRV analysis as an indicator of cardiac autonomic regulation. Compared with low WHR subjects, high WHR subjects had significantly lower values of rMSSD, pNN50, HF, and SD1, suggesting decreased parasympathetic activity. No such differences in LF/HF ratio were found between the WHR-based subgroups. Bivariate correlation analysis showed that obesity indices of WC, WHR, and %BF were significantly associated with rMSSD, pNN50, HF, and SD1, with a tendency for correlation coefficient to be higher with WHR than with WC or %BF. No significant association was found between BMI and HRV parameters indicative of parasympathetic activity. This study suggest that central obesity is significantly associated with decrease in parasympathetic activation, independent of BMI as an indicator of obesity, in male college smokers.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.221-225
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• 1998

From February 1996 to May 1997, 18 patients underwent mitral valve repair for mitral regurgitation. There were 9 male and 9 female patients aged from 19 to 68 years(mean, 53). Thirteen patients were in New York Heart Association(NYHA) class III and IV. The cause of mitral regurgitation was degenerative in 12 patients, rheumatic in 5 patients and infective in 1 patient. Fifteen patients were in Carpentier's functional classification II, 2 patients in Carpentier's class III and 1 patient in Carpentier's class I. Surgical procedures included prosthetic ring annuloplasty(16 cases), rectangular resection of posterior leaflet(15 cases), chordal shortening(5 cases), triangular resection of anterior leaflet(2 cases), commissurotomy(2 cases), partial transposition of posterior leaflet(1 case). These procedures were combined in most patients. There was no operative death. These patients have been followed from 1 to 15 months, mean of 6.7 months. There was one late death resulted from low cardiac output following mitral valve replacement. The function of the repaired valve in other 17 patients has remained satisfactory during the observed interval. We consider that mitral valve repair is highly satisfactory in patients with mitral regurgitation.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.206-216
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• 2013

The emotion plays a critical role in human's daily life including learning, action, decision and communication. In this paper, emotion discrimination classifier is designed to reduce system complexity through reduced selection of dominant features from biosignals. The photoplethysmography(PPG), skin temperature, skin conductance, fontal and parietal electroencephalography(EEG) signals were measured during 4 types of movie watching associated with the induction of neutral, sad, fear joy emotions. The genetic algorithm with support vector machine(SVM) based fitness function was designed to determine dominant features among 24 parameters extracted from measured biosignals. It shows maximum classification accuracy of 96.4%, which is 17% higher than that of SVM alone. The minimum error features selected are the mean and NN50 of heart rate variability from PPG signal, the mean of PPG induced pulse transit time, the mean of skin resistance, and ${\delta}$ and ${\beta}$ frequency band powers of parietal EEG. The combination of parietal EEG, PPG, and skin resistance is recommendable in high accuracy instrumentation, while the combinational use of PPG and skin conductance(79% accuracy) is affordable in simplified instrumentation.

• Journal of Digital Convergence
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• v.19 no.5
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• pp.263-268
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• 2021

The purpose of this study was to propose a model which is suitable for the actual delivery system by designing a fetal delivery hospital operation management and fetal health classification model. The number of deaths during childbirth is similar to the number of maternal mortality rate of 295,000 as of 2017. Among those numbers, 94% of deaths are preventable in most cases. Therefore, in this paper, we proposed a model that predicts the health condition of the fetus using data like heart rate of fetuses, fetal movements, uterine contractions, etc. that are extracted from the Cardiotocograms(CTG) test using a random forest. If the redundancy of the data is unbalanced, This proposed model guarantees a stable management of the fetal delivery health management system. To secure the accuracy of the fetal delivery health management system, we remove the outlier which embedded in the system, by setting thresholds for the upper and lower standard deviations. In addition, as the proportion of the sequence class uses the health status of fetus, a small number of classes were replicated by data-resampling to balance the classes. We had the 4~5% improvement and as the result we reached the accuracy of 97.75%. It is expected that the developed model will contribute to prevent death and effective fetal health management, also disease prevention by predicting and managing the fetus'deaths and diseases accurately in advance.

• Sleep Medicine and Psychophysiology
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• v.19 no.2
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• pp.68-76
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• 2012

Objectives: Sleep disorders cause changes of autonomic nervous system (ANS) which affect cardiovascular system. Primary insomnia (PI) makes acceleration of sympathetic nervous system (SNS) tone by sleep deficiency and arousal. Obstructive sleep apnea syndrome (OSAS) sets off SNS by frequent arousals and hypoxemias during sleep. We aimed to compare the changes of heart rate variability (HRV) indices induced by insomnia or sleep apnea to analyze for ANS how much to be affected by PI or OSAS. Methods: Total 315 subjects carried out nocturnal polysomnography (NPSG) were categorized into 4 groups - PI, mild, moderate and severe OSAS. Severity of OSAS was determined by apnea-hypopnea index (AHI). Then we selected 110 subjects considering age, sex and valance of each group's size [Group 1 : PI (mean age=$41.50{\pm}13.16$ yrs, AHI <5, n=20), Group 2 : mild OSAS (mean age=$43.67{\pm}12.11$ yrs, AHI 5-15, n=30), Group 3 : moderate OSAS (mean age $44.93{\pm}12.38$ yrs, AHI 16-30, n=30), Group 4 : severe OSAS (mean age=$45.87{\pm}12.44$ yrs, AHI >30, n=30)]. Comparison of HRV indices among the four groups was performed with ANCOVA (adjusted for age and body mass index) and Sidak post-hoc test. Results: We found statistically significant differences in HRV indices between severe OSAS group and the other groups (PI, mild OSAS and moderate OSAS). And there were no significant differences in HRV indices among PI, mild and moderate OSAS group. In HRV indices of PI and severe OSAS group showing the most prominent difference in the group comparisons, average RR interval were $991.1{\pm}27.1$ and $875.8{\pm}22.0$ ms (p=0.016), standard deviation of NN interval (SDNN) was $85.4{\pm}6.6$ and $112.8{\pm}5.4$ ms (p=0.022), SDNN index was $57.5{\pm}5.2$ and $87.6{\pm}4.2$ (p<0.001), total power was $11,893.5{\pm}1,359.9$ and $18,097.0{\pm}1,107.2ms^2$(p=0.008), very low frequency (VLF) was $7,534.8{\pm}1,120.1$ and $11,883.8{\pm}912.0ms^2$ (p=0.035), low frequency (LF) was $2,724.2{\pm}327.8$ and $4,351.6{\pm}266.9ms^2$(p=0.003). Conclusions: VLF and LF which were correlated with SNS tone showed more increased differences between severe OSAS group and PI group than other group comparisons. We could suggest that severe OSAS group was more influential to increased SNS activity than PI group.

• Journal of Chest Surgery
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• v.35 no.9
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• pp.672-674
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• 2002

A 40-years-old male with dilated cardiomyopathy(DCMP) and end-stage heart failure had undergone partial left ventriculectomy(PLV) in July 1997 and then underwent cardiac transplantation in January 1999. Three months later he showed increased ejection fraction (EF) from 26% to 42.6%, decreased left ventricular end diastolic diameter(LVEDD) from 71mm to 45mm, cardiac output(CO) 3.95 L/min and cardiac index(CI) 2.28 L/min/m$^2$echocardiographically. Eight months later, left ventriclular end diastolic and systolic diameters increased to 56 and 51 mm respectively and EF decreased to 17% in echocardiographic follow-up. He had been on maximum medication until he underwent cardiac transplantation 18 months after the PLV. Consecutive myocardial biopsies (1, 3 and 6 month later) showed ISHLT (international society of heart and lung transplantation) class la and the treatment for rejection was not needed until now on. We report a partial left ventriculectomy as a successful bridge to cardiac transplantation in a patient with DCMP and end-stage heart failure.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.423-429
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• 2015

The purpose of this research was to examine the effect of dance sports for twelve weeks on physical self-efficacy in post-menopausal depression obese women. A total 38 women participated in this study, and they were divided into three groups: mild-depression group(n=9), light-depression group(n=14) and control group(n=15). For the exercise program in this study, a dance sports program performed at an intensity of heart rate reserve 50~80%, 60 minutes of exercise time, and the frequency of 3 times a week. Physical self-efficacy for mild-depression group after 12-week dance sports program was significantly increased compared to before the exercise. Although light-depression group and control group didn't show significant increase in physical self-efficacy, dance sports is expected to act positively on mental stability, such as depression and hope used as an effective tool to improve the quality of life. Furthermore, we expect a convergence is achieved between the sports science and medical research sectors.

• The Journal of Society for e-Business Studies
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• v.22 no.2
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• pp.1-18
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• 2017

Recently, identification of the extremely stressed condition of children is an essential skill for real-time recognition of a dangerous situation because incidents of children have been dramatically increased. In this paper, therefore, we present a model based on machine learning techniques for stress status identification of a child by using bio-signals such as voice and heart rate that are major factors for presenting a child's emotion. In addition, a smart band for collecting such bio-signals and a mobile application for monitoring child's stress status are also suggested. Specifically, the proposed method utilizes stress patterns of children that are obtained in advance for the purpose of training stress status identification model. Then, the model is used to predict the current stress status for a child and is designed based on conventional machine learning algorithms. The experiment results conducted by using a real-world dataset showed that the possibility of automated detection of a child's stress status with a satisfactory level of accuracy. Furthermore, the research results are expected to be used for preventing child's dangerous situations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.418-425
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• 2013

In this study, the three scents effects on subjects due to EEG type, and it researched to find optimal scent to increase their amenity and productivity. EEG and HRV were compared and analyzed in the environmental test room by classifying subjects into two type: A and B. The condition of the environmental test room was in temperature 31[$^{\circ}C$], relative humidity 50[RH%], air current speed 0.02[m/s] and illuminance 1000[lux] with setting up three different scents which are Rosemary, Jasmine and Hazelnut. The result of this study, at Jasmine scent for A and B type, relative ${\alpha}$ wave, SEF50, $\frac{SMR}{\theta}$ and SDNN were revitalized, and ${\alpha}$ wave asymmetry index, HRT, stress index and fatigue degree were decreased. It was found that favorite scent of A and B type is same as Jasmine scent, but A type was more sensitive than B type about scent. Therefore Jasmine scent is very effective to increase amenity, productivity and concentration, and to decrease stress and fatigue degree.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.484-487
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• 2014

In this paper, We describe antenna characteristics for efficiently detecting human signs using small, planar and low power antenna. Then we can measure biological signals including respiration, heart rate, blood pressure, and blood sugar, using UWB (Ultra Wide Band) pulses, while does not contact the human body. The antenna need stable and wideband impedance characteristic, because it use gaussian pulse signal. Usually it has trade-off between wideband impedance and gain. But we don't considered array type antennas because we want to need small size. Generally the antennas that classified as frequency independent satisfy our requirements. Frequency independent antennas include spiral, log-periodic, sinuous, and etc. These antennas are possible to have shape planar type. In this paper, We tested these kind antenna's characteristics in center frequency 5 GHz, Especially circular patch and sinuous antenna designed and analyzed.