• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.12 s.354
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• pp.74-80
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• 2006

This work presents a novel architecture of phase locked loop (PLL) with the current compensating scheme to improve phase noise performance. The proposed PLL has two Charge Pump (CP), main-CP (MCP) and sub-CP (SCP). The smaller SCP current with same time duration but opposite direction of UP/DN MCP current is injected to the loop filter (LF). It suppress the voltage fluctuation of LF. In result, it improves phase noise characteristic. The Proposed PLL has been fabricated with 0.35fm 3.3V CMOS process. Measured phase noise at 1-MHz offset is -103dBc/Hz resulting in a minimum 3dBc/Hz phase noise improvement compared to the conventional PLL.

• Korean Journal of Biological Psychiatry
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• v.15 no.3
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• pp.186-193
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• 2008

Objectives : The authors tried to investigate the characteristics of Heart Rate Variability(HRV) among the subjects with metabolic syndrome for testing the possibility of clinical application of HRV in evaluating metabolic syndrome. Methods : We examined the difference of the means of HRV between 122 subjects of metabolic syndrome and 1057 healthy controls using T-test, and the change of means in HRV according to increasing risk factors of metabolic syndrome. Using multiple regression analysis, we examined the association of HRV with the risk factors of metabolic syndrome. Results : The HRV indices including SDNN(Standard Deviation of all normal NN intervals), RMSSD(the square Root of the Mean Squared Differences of successive all normal NN interval), TP(Total Power), LF(Low Freuency), and HF(High Frequency) were significantly lower in the metabolic syndrome group than in the normal control group, and the means of all HRV indices except LF/HF were decreased consistently according to increasing risk factors of metabolic syndrome. The fasting glucose, triglyceride, and waist circumference were dependent factors that contributed significantly to the change of HRV. Conclusion : These findings suggest metabolic syndrome adversely affects cardiac autonomic system and HRV could be a useful method for evaluating metabolic syndrome.

• Journal of Oriental Neuropsychiatry
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• v.17 no.2
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• pp.133-145
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• 2006

Objective : The purpose of this experimental-controlled study was to investigate the characteristics of the autonomic nervous system in students with Keongke by using HRV(Heart rate variability) and PSV(Pupil size variability). Method : The study group was consisted of 11 students with self recognition as the experimental group, and 25 normal students as the control group. Informations on gender and age were obtained by medical charts and personal interviews. By using heart rate variability and pupil size variability, we measured the value of HRT(Heart rate), SDNN(Standard deviation of NN intervals), LFnorm(Low frequency normalization), HFnorm(High frequency normalization), LF/HF ratio, Pupil area, B.S.(Basic size), C.R.(Max Constriction Rate) and 1s.d.(1sec Dilation Rate). I compared the degrees of the sympathetic and parasympathetic activity. Result : 1. In the result of heart rate variability between experimental and control group, none of the parameters of experimental group were significantly different from control group. And even though there were no statistical significance, there were some numerical differences in SDNN, LF norm, HF norm. 2. In pupil size variability, C.R. and 1s.d. of the experimental group were increased compared to control group. Conclusion : The study results suggest that the group with Keongke has differences of autonomic nervous system as compared to those in normal state. Measurement value of PSV is a new technical approach to estimate the autonomic nervous system.

• Journal of Haehwa Medicine
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• v.22 no.2
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• pp.81-92
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• 2014

Objective : The purpose of this study was to assess the effects of Cyperus rotundus L. essential oil on relaxation in highly stressed volunteers with heart rate variability(HRV) and electroencephalography(EEG). Methods : 11 highly stressed volunteers participated in this study. The volunteers were examined with HRV and EEG before and after inhalation of Cyperus rotundus L. essential oil. Results : After smelling Cyperus rotundus L. essential oil, mean RR(mean of RR intervals) was incresed significantly(p<0.01), mean HRV(mean of heart rate), HF(high frequency) were decreased significantly(p<0.01). norm LF(low frequency), LF/HF ratio were decreased significantly(p<0.05), norm HF(normalized high frequency) was increased significantly(p<0.05) on HRV. After smelling Cyperus rotundus L. essential oil, relative ${\theta}$ power was decreased significantly(p<0.05) at P3(left parietal) and relative ${\alpha}$ power was increased significantly(p<0.05) at Fp1(left prefrontal), Fp2(right prefrontal) and relative ${\beta}$ power was decreased significantly(p<0.05) at Fp1(left prefrontal) and relative ${\gamma}$ power was decreased significantly(p<0.05) at Fp1(left prefrontal) on EEG. Conclusions : This results show that inhalation of Cyperus rotundus L. essential oil effects on relaxation and decreasing stress.

• Journal of Korean Medicine for Obesity Research
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• v.8 no.1
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• pp.63-70
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• 2008

Objectives Obesity is the major risk factor of the heart disease and the metabolic disease. The autonomic nervous system is a key contributor in the regulation of energy balance, so the blunted activity may contribute to the maintenance of the obese state. So we evaluated the function of the autonomic nervous system in young overweight and obese women with heart rate variability. Methods The subjects were 26 overweight and obese young women(BMI〉$23kg/m^2$) and 25 lean women who visited Kangnam Kyunghee hospital for obesity management from March 2006 to April 2008. Bioimpedance Analysis (BIA), short-term spectral analysis of heart rate variability (HRV) were performed. Results HRV of obese young group was lower than the lean young group, but there is no statistical significance. BMI had significantly a negative correlation with Low Frequency(LF) of HRV. LF power is mediated by sympathetic nervous system activity. These results indicate a decrease of sympathetic modulation in overweight and obese young women. Conclusions Overweight and obese young women have decreased sympathetic nervous system activity. In clinical practice, an assessement of HRV would be noninvasive and sensitive methods for sympathetic nervous system of young overweight and obese women.

• Journal of Environmental Health Sciences
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• v.41 no.4
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• pp.223-230
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• 2015

Objectives: There is considerable evidence that polluted ambient air contributes to the risk of cardiovascular morbidity and mortality. Heart rate variability (HRV) is defined as the variation in heartbeat intervals and has been reported as a biological marker of cardiovascular disease. This article reviews the existing literature in order to examine the association between air pollution and HRV. Methods: Literature was searched using Web of Science with the key words of "air pollution", "heart rate variability" and other related terms. A total of 156 articles were listed. For review, 21 of those listed publications were chosen after excluding studies regarding chamber studies, occupational environment, secondhand smoke and automobile exhaust. Results: Research methods employed in the publications were classified by type of participants (elderly/adult), air pollution monitoring (ambient/personal) and HRV monitoring (continuous/spot). Among HRV parameters, power in the low frequency range (LF), power in the high frequency range (HF) and standard deviation of all NN intervals (SDNN) were all associated with air pollutants. The chosen studies were mostly based on elderly populations. In studies based on continuous HRV monitoring, LF and SDNN significantly decreased when $PM_{2.5}$ exposure increased. Conclusion: Continuous HRV monitoring combined with personal exposure monitoring has been one of the most common study methods in recent publications. We expect that this review will be useful for the study of the association between air pollution and cardiovascular effects using HRV.

• Journal of Sasang Constitutional Medicine
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• v.28 no.2
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• pp.123-131
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• 2016

Objectives We observed what effects of Paced Breathing(PB) in specific respiration rate have on heart rate variability (HRV) according to Sasang Constitution.Methods HRV of 72 healthy participants in sitting position was recorded while they carried out usual breathing, 0.2Hz, 0.1Hz, and 0.05Hz PB each 5 minutes in consecutive order. Five minute of relaxation was permitted between each breathing. Finally, HRV indices were statictically analyzed of 32 participants (SOEUM: 11, SOYANG: 10, TAEEUM: 11) after data out of accord with respiration rate or outliers were excluded.Results and Conclusions According to respiration rates, there was no statistical significance of HRV among Sasang Constitution. Regardless of Sasang Constituion, 0.2Hz PB increased mean heart rate and decreased natural logarithmic low frequency(lnLF) oscillation of HRV without the change of natural logarithmic high frequency(lnHF), while 0.1Hz PB increased lnLF and standard deviation of N-N interval(SDNN), and slightly decreased lnHF without the change of mean heart rate. 0.05 Hz PB also showed the same effect as 0.1Hz PB, but was impracticable.

• The Journal of Korean Obstetrics and Gynecology
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• v.32 no.4
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• pp.25-38
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• 2019

Objectives: The purpose of this study is to analysis differences of heart rate variability (HRV), body composition, digital infrared thermal imaging (DITI), and electro pulse graph by whether there are some causes of dysmenorrhea or not. Methods: We studied 89 patients who took at least one test among HRV, Body composition, DITI, and electro pulse graph visiting Kyung Hee University Hospital at Gangdong from March 1, 2014 to May 7, 2019. Results: There were statistically significant differences in Low frequency (LF), LF norm and High frequency norm (HF norm) of HRV between primary dysmenorrhea patients and secondary dysmenorrhea patients. There were statistically significant differences in Body Mass Index (BMI) and body fat percentage of Body composition between two groups. But both BMI were included in normal range. There were no statistically significant difference in DITI results. And there was significant difference of Estimated circulation resistance (ECR) between two groups. Conclusions: The results suggest that hormone imbalance of secondary dysmenorrhea patients can affect HRV results. And because of high ECR, phlegm pathology can be more considered in secondary dysmenorrhea patients. Further study should be conducted to confirm the results of body composition and DITI differences.

• Korean Journal of Exercise Nutrition
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• v.13 no.2
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• pp.155-160
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• 2009

PURPOSE. The purpose of this study was to investigate the effects of fasting and high-fat diet feeding on uncoupling protein 3 (UCP3) mRNA levels, uncoupling the respiratory chain and producing heat, of skeletal muscle in rat. METHODS. Fasting experiment: Forty Male Sprague-Dawley rats (5 wk) were divided into non-fasting groups (CON) and fasting groups (FG) for 0 day, 0.5 day (12 hr), 1 day, 2 day and 3 day. The rats of CON were sacrificed at 0 and 3 day. High-fat diet experiment: Forty Male Sprague-Dawley rats (5 wk) were divided into low-fat diet groups (LF) and high-fat diet group feeding for 0 day, 0.5 day (12 hr), 1 day, 2 day and 3 day. The rats of LF were sacrificed at 0 and 3 day. Analysis: Analysis of UCP3 mRNA expression was used by Real-time PCR. RESULTS. UCP3 mRNA levels of FG group were increased according to time course for 2 days- fasting but decreased at 3 day-fasting. UCP3 mRNA of HF were increased during HF diet feeding for 2 day, and peaked at 1 day-HF feeding, but decreased 2 day and 3 day-HF feeding CONCLUSION. Therefore, it may be rational that UCP3 is up-regulation when a large amount of fatty acids influx occurs in skeletal muscles as well as might have a role for fine adjustments of energy expenditure.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.27-39
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• 2023

Purpose : The aim of this study was to identify the influence of transient isokinetic exercise on cardiac autonomic modulation and muscle properties in healthy male subjects. Methods : Twenty-eight healthy males underwent isokinetic exercise of both knee joints using a Biodex systems 3 isokinetic dynamometer with an angular velocity of 60 °/sec. The changes in activity of the autonomic nervous system, as determined by heart rate variability (HRV), and in muscle properties were evaluated at three times: pre-exercise, immediately post-exercise, and 10 min post-exercise. Results : The time domain analysis of HRV revealed significant changes in the beat count and mean and minimal heart rate (HR) measured at pre-exercise, immediately post-exercise, and 10 min post-exercise (p<.001). The beat count and mean HR were markedly increased immediately post-exercise compared to pre-exercise, but then significantly decreased at 10 min post-exercise (p<.001). All parameters of the frequency domain were significantly altered by isokinetic exercise (p<.01). The low frequency/high frequency (LF/HF) ratio, as an index for the sympathovagal balance, was elevated by exercise and remained at a similarly high level at 10 min post-exercise (p<.01). The muscle properties of rectus femoris were changed as follows: Muscle tone and stiffness were significantly increased between pre-exercise and immediately post-exercise (p<.001), and between pre-exercise and at 10 min post-exercise (p<.001). Whereas, the elasticity showed no significant change. Conclusion : These results demonstrated that transient isokinetic exercise could induce changes in cardiac autonomic control and muscle properties. In particular, up-regulation of LF/HF ratio after exercise signifies thus enhanced sympathetic modulation by isokinetic exercise. Therefore, it is needed to understand the cardiovascular risks that may arise during isokinetic exercise for providing the basic evidence to establish appropriate isokinetic exercise protocols as effective rehabilitation exercises.