• Journal of Acupuncture Research
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• 제29권6호
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• pp.47-56
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• 2012

Objectives : This study was performed to investigate the effect of acupuncture at Yintang point(EX-$HN_3$) on heart rate variability in healthy adults with mental stress. Methods : 38 healthy volunteers(sham point group : 19, Yintang point group 19) participated in this study. The study was established by randomized trial. After 10 minutes rest period, mental stress was provided for 10 minutes. HRV was recorded before and after stress. And then simple acupuncture was applied at sham or Yintang point for 15 minutes. We measured HRV 3 times: before and after stress, and after acupuncture. Results : In sham point group, LF norm and HF norm changed significantly after mental stress. In Yintang point group, LF, HF, LF norm, HF norm and LF/HF showed a significant change after mental stress. In sham point group, all indicators were not affected after acupuncture. In Yintang point group, HF norm decreased significantly. LF, LF norm and LF/HF increased significantly. There were significant differences between two groups(p<0.05). Conclusions : The results suggest that acupuncture at Yintang point(EX-$HN_3$) can regulate and prevent the alteration of autonomic nerve system by mental stress.

• 한국컴퓨터정보학회논문지
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• 제16권2호
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• pp.17-23
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• 2011

본 연구에서는 일상생활 속에서의 심전도를 측정하여 HRV(Heart Rate Variability)를 모니터링 하며 스트레스를 추정할 수 있는 시스템을 제안한다. 제안된 무선 생체 측정기 모듈은 전처리필터와 BFP사용으로 잡음은 감소 시키면서 신호의 크기는 증가시키기는 회로를 설계하였고, ECG를 측정하여 R-wave를 추출하고 이를 통한 HRV로 인간의 감성 중 스트레스를 평가하는 알고리즘을 개발하였다. 또한 무선 생체 측정기 시스템은 활동 모니터링을 위해 휴대하기 편한 사각형의 작은 사이즈로 구성되며 측정방법이 간단하여 언제든지 측정이 가능하다. 실험을 통해서 취득한 사용자의 HRV 정보는 스트레스 평가 지수 도출 알고리즘을 통한 스트레스를 추정할 수 있으며 스트레스 부하 프로토콜을 수행 한 전후를 비교 분석하여 많은 파라미터에서 유의미한 차이가 나타났다. 본 연구에서 수행된 실험은 일상생활 중에 심장의 전기 활동을 모니터링 할 수 있는무선 생체측정기를 개발하였으며 이를 이용하여 시간영역 분석 및 주파수 영역 분석을 통하여 스트레스 지수를 평가 할 수 있는 알고리즘 시스템은 건강 모니터링 시스템으로 활용도가 높을 것으로 기대된다.

• 대한통합의학회지
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• 제6권3호
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• pp.11-16
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• 2018

Purpose: Stress tends to cause sympathetic hyperactivity and increase blood cortisol levels. The vagus nerve is a parasympathetic nerve that is involved in relaxing the body. The purpose of this study was to investigate the effects of electrical stimulation of the vagus nerve on stress hormone (cortisol) levels and heart rate variability (HRV) in humans. Methods: A total of 10 healthy subjects participated in the pilot experiment. All subjects underwent electrical vagus nerve stimulation for 20 minutes in the cymba conchae of the left ear. An electro cardiogram meter was used to measure HRV. Blood samples were collected and analyzed for cortisol levels. The standard deviation of all normal N-N intervals (SDNN), root mean square of successive differences (RMSSD), low frequency, high frequency, and cortisol levels were compared in pre and post mean values after the intervention. Data were analyzed using the Wilcoxon's signed-rank test. Results: Coritsol levels were observed to decrease after vagus nerve electrical stimulation. The mean SDNN and RMSSD values were increased after the intervention, but not significantly. Conclusion: Vagus nerve electrical stimulation has been shown to increase the ability of the parasympathetic nerve to adapt to upward regulation and stress. Vagus nerve electrical stimulation could thus be an effective treatment for modern social psychological stress control.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.52-53
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• 2005

Time series of gridded surface wind and wind-stress vectors over the world ocean have been constructed by satellite scatterometer data. The products are derived from the ERS-l,2 covering 9 years during 1992-2000 and the Sea Winds on board QuikSCAT (Qscat) which has been operating up to the present since June 1999, so they allows us to analyze variabilities with various time scales. In this study, we focus on interannual variability of the wind stress in the mid- and high-latitude region of North Pacific. These are compared with those by numerical weather prediction(NWP) ones (NCEP Reanalysis). We also examine variability in the wind-stress curl field that is an important factor for ocean dynamics and focus its time and spatial characters in the northwestern Pacific around Japan. It is found that the vorticity field in the lower atmosphere tends to increase gradually with time, suggesting the enhancement of the North Pacific subtropical gyre.

• Journal of Acupuncture Research
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• 제26권5호
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• pp.49-56
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• 2009

Objectives : The purpose of this study was to assess the effect of Hwangryunhaedok-tang pharmacopuncture at $CV_{17}$ for reducing mental stress using power spectrum analysis of the heart rate variability(HRV). Methods : 30 healthy volunteers(control group: 15, experimental group: 15) participated in this study. After instrumentation and 5-minutes rest period, mental stress by operation was provided for 5-minutes. HRV was recorded before and after the mental stress. And then the control group rested for 15-minutes. The experimental group was injected Hwangryunhaedok-tang pharmacopuncture at $CV_{17}$ and rested for 15-minutes. And then HRV was recorded. Results : In simple rest group, LF norm and HF norm showed a significant change after mental stress. In pharmacopuncture group, LF norm, HF norm and LF/HF showed a significant change after mental stress. But there were no significant difference between two groups(p>0.05). In pharmacopuncture group, LF norm, HF norm and LF/HF showed a significant change after pharmacopuncture injection. There were significant difference between two groups(p<0.01). Conclusions : The result suggests that Hwangryunhaedok-tang pharmacopuncture at $CV_{17}$(Jeonjung) can regulate and prevent the alteration of autonomic nerve system due to mental stress.

• Journal of Acupuncture Research
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• 제27권2호
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• pp.51-58
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• 2010

Objectives : The purpose of this study was to assess the effect of $PC_6$ moxibustion treatment for reducing mental stress using power spectrum analysis of the heart rate variability(HRV). Methods : 20 healthy volunteers(simple rest group : 10, moxibustion treatment group : 10) participated in this study. After instrumentation and 5-minutes rest period, mental stress by operation was provided for 5-minutes. HRV was recorded before and after the mental stress. And then the simple rest group rested for 15-minutes. The moxibustion treatment group was treated by $PC_6$ moxibustion and rested for 15-minutes. And then HRV was recorded. Results : In simple rest group, LF norm and HF norm showed a significant change after mental stress. In moxibustion treatment group, LF, HF, LF norm, HF norm and LF/HF showed a significant change after mental stress. But there were no significant difference between two groups(p>0.05) except HF. In moxibustion treatment group, LF, LF norm, HF norm and LF/HF showed a significant change after moxibustion treatment. There were significant differences between two groups(p<0.05). Conclusions : The result suggests that $PC_6$ moxibustion treatment can regulate and prevent the alteration of autonomic nerve system by mental stress.

• Journal of Acupuncture Research
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• 제27권5호
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• pp.51-58
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• 2010

Objectives : The purpose of this study is to assess the effect of laser acupuncture at $HT_7$ for reducing mental stress using power spectrum analysis of the heart rate variability. Methods : 36 healthy volunteers(control group: 18, treatment group: 18) participated in this study. After instrumentation and 5-minute rest period, 5-minute metal stress by operation was provided. HRV was recorded before and after the mental stress(1st, 2nd HRV). After 2nd HRV recording, the control group rested for 15 minutes without any treatments. Participants in the treatment group received laser acupuncture to $HT_7$ unilaterally and rested for 15minutes. Points were irradiated for 60seconds, and the intensity was 1.8J(output 20%). And then 3rd HRV was recorded. Results : In simple rest group, LF norm showed a significant change after mental stress. In laser acupuncture group, LF norm, HF norm, LF, HF and LF/HF ratio showed a significant change after mental stress. But there were no significant difference between two groups(ANCOVA test, p>0.05). In laser acupuncture group, LF norm, HF norm, HF and LF/HF ratio showed a significant change after laser acupuncture treatment. And there were significant differences between two groups(p<0.05). Conclusions : This study suggests that laser acupuncture at $HT_7$ can regulate and prevent the alternation of autonomic nervous system due to mental stress.

• 한국항공운항학회지
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• 제30권2호
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• pp.70-77
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• 2022

This study is a study to analyze the stress difference of pilots according to the category of aircraft. According to previous studies, pilot stress is affected by several factors such as flight time, fatigue regulation, and operating environment, and it is known that stress also affects cardiac variability. In this paper, we analyzed that there is a difference in stress according to the operating environment through airline pilots and pilots of educational institutions, and then tested the difference in stress between airplane pilots and helicopter pilots. This study differs in that it is a study that has almost no empirical research on pilot fatigue and stress considering the role of flight crew members and operational conditions for each mission. If we expand and verify the sample of the results for the stress difference in the future, it will be a great contribution to practical aviation safety research in connection with the fatigue risk management system in the future.

• Korea-Australia Rheology Journal
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• 제18권1호
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• pp.15-24
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• 2006

The first international inter-laboratory study, involving six laboratories, has been conducted to examine issues associated with yield stress measurements in suspensions. The initial focus of the project was to evaluate the reliability and reproducibility of several common yield stress measuring techniques employed in different laboratories and with different instruments. Aqueous suspensions of colloidal $TiO_2$ at concentrations of 40-70 wt% solids were used as the test fluids. A wide range of instruments and techniques employing both direct and indirect methods were used to determine the yield stress of the samples prepared according to a prescribed procedure. The results obtained indicated that although variations of results existed among different techniques, direct yield stress measurements using static methods produced more reliable and repeatable results than other methods. Variability of the yield stress measured using different techniques within any laboratory however was less significant than variability of the results among different laboratories. The nature and condition of the test suspensions was identified as the most likely factor responsible for the poor reproducibility of yield stress measurements from different laboratories.

• 동의신경정신과학회지
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• 제22권1호
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• pp.1-12
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• 2011

Objectives : This study was conducted to assess effects of oriental medicine music therapy on heart rate variability(HRV) in normal subjects under mental stress. Methods : 34 healthy volunteers(control group:17, experimental group:17) participate in this study. The volunteers were randomly allocated into two groups. After 10-minutes rest period and instrumentation, both groups performed a mental stress test for 12-minutes. HRV was recorded before and after the mental stress. And then the experimental group applied oriental medicine music therapy for 10-minutes. In the control group, they rested for 10-minutes. And HRV was recorded. Results : After giving mental stress stimulation to both groups, LF and LF/HF ratio were significantly increased and HF, mean HRV were decreased. In experimental group, LF, LF/HF ratio were significantly decreased and HF, SDNN were significantly increased after applying oriental medicine music therapy. In control group, LF was significantly decreased. And LF/HF ratio was decreased and HF, SDNN were increased, but it was not significant. Conclusions : This results show that oriental medicine music therapy could be relatively useful to decrease sympathetic activity and prevent the alteration of autonomic nervous system due to mental stress.