• 인간식물환경학회지
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• 제22권3호
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• pp.309-319
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• 2019

This study was conducted to investigate the effects of watching a virtual reality (VR) forest video on stress reduction in adults. Experiments were performed in an artificial climate chamber where temperature, humidity and illumination were controlled. To cause stress in subjects, the subjects were asked to multiply two digit numbers by one digit numbers for two minutes. The subjects then watched a VR forest video for five minutes. During the experiment, the heart rate variability (HRV) and heart rate (HR) of subjects were continuously measured for evaluating their physiological state. After measuring the baseline and watching a VR forest video, their psychological state was evaluated using the profile of mood state (POMS), semantic differential (SD) method, and positive affect and negative affect schedule (PANAS). The results of physiological evaluation after watching a VR forest video showed a decrease in the stress index and HR, an increase in the activity of the parasympathetic nervous system, and the standard deviation of normal to normal RR intervals (SDNN). The results of psychological assessment confirmed that watching a VR forest video induced "comfort", "natural", and "soothed" feelings in subjects. In addition, watching a VR forest video decreased "tension-anxiety (T-A)", "depression-dejection (D)", "anger-hostility (A-H)", "fatigue (F)", "total mood disturbance (TMD)", and increased "vigor (V)" compared to the base line, and decreased "negative affect" and increased "positive affect." These results indicate that watching a VR forest video decreases adults' stress index, stabilizes physiological state, and has a positive impact on psychological state. The findings of this study can serve as a basis for providing forest welfare services to people in the blind spots of forest welfare, and can lay a foundation for the adoption of VR, one of the technologies of the fourth industrial revolution in forestry.

• 수면정신생리
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• 제19권1호
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• pp.27-34
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• 2012

목 적 : HRV 검사는 교감 신경과 부교감 신경의 억제 체제에 의해 조절되는 심박변이도를 측정하고 분석하는 도구로서, 현재 민감하고 비침습적인 도구로 인정받고 있다. 우울증 환자들은 불안, 우울과 같은 정신적 스트레스를 지속적으로 받으면서 자율신경계 억제 기전의 교란을 받게 된다. 우울증은 또 심혈관 질환의 이환과 사망률을 예측하는 독립적 예측인자라고 보고되고 있다. 본 연구에서는 HRV 검사를 통하여 정상인과 우울증 환자 사이에서 HRV와 lipid level 사이의 상관관계를 알아보려고 하였다. 방 법 : 2011년 7월부터 2012년 3월까지 서울의료원 정신건강의학과 우울증 클리닉에 내원한 외래 및 입원 환자 중, 만 19세 이상 65세 이하 환자(42명)를 대상으로 하였고, 환자들과 나이, 성별을 일치시킨 병원에서 근무하는 직원 중 정신과 과거력과 신체 질환이 없는 사람(32명)을 대상으로, HRV, 혈중 지질 농도, HAM-A(hamilton anxiety scale), HAM-D(hamilton depression scale)를 조사하였다. 우울증 환자군과 정상대조군을 독립표본 t-검정 및 카이제곱-검정을 시행하여 비교하였다. Pearson 상관 분석을 이용하여 우울 증상의 심각도, HRV 세부지표, 혈중 지질 농도 간의 상관관계를 살펴보았다(p<0.05). 결 과 : 우울증 환자군과 정상대조군 사이에 인구학적 변인은 차이가 없었으며, 우울증 환자군에게서 HAM-D & HAM-A 점수가 높았다. 혈중 지질 농도 검사에서, 우울증 환자군이 정상군보다 cholesterol, TG, LDL 수치가 유의하게 높게 측정되었다. HRV 시간영역 분석(time domain analyses)에서, 우울증 환자군이 정상군보다 SDNN이 낮게 나왔으나 유의한 차이는 보이지 않았다. 한편, ApEn(approximate entrophy)이 정상군보다 우울증 환자군에서 유의하게 높았으며, ApEn은 LDL, HAM-D, HAM-A와 유의한 상관관계를 보였다. 결 론 : 우울증 환자군의 HRV에서 ApEn이 정상대조군보다 높게 측정되었다. ApEn은 최근에 개발된 비선형적 분석으로 HRV 신호가 얼마나 복잡한 지를 통계적으로 정량화한 수치이며, 데이터 양이 적고, 잡음이 많은 생리학적 데이터를 분석하기에 적합하다고 알려져 있다. 본 연구에서는 ApEn이 우울증 환자군에서 유의하게 높게 나왔으며, ApEn이 LDL, HAM-D, HAM-A와도 상관관계를 갖는 것으로 나타났다. 향후, HRV를 임상적 상황에서 실용적으로 사용하는 연구에 있어, ApEn을 새로운 평가 도구로서 주목할 필요가 있겠다.

• 수면정신생리
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• 제25권1호
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• pp.15-20
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• 2018

목 적 : 본 연구는 우울장애 환자를 대상으로 안정 시와 기립 시기, 정신적 스트레스 시기에 심박변이도 지수(heart rate variability index, HRV index) 검사를 시행하여 자율신경계 불균형이 육체적 및 정신적 스트레스에서 어떻게 변화되는 지 알아보고자 하였다. 방 법 : 우울장애 환자 62명을 대상으로 연구를 수행하였다. 안정 시기, 기립 시기, 정신적 스트레스 자극을 준 시기동 안 각각 심박변이도 지수를 측정하였다. 긴장 정도와 스트레스 정도에 대해 visual analogue scale (VAS) score로 측정하였고, Beck depression inventory (BDI), state trait anxiety inventory-I, II (STAI-I, II)를 사용하여 불안증상과 우울증상 의 심각도를 평가하였다. 통계적 검증은 안정 시기와 기립 시기, 안정 시기와 정신적 스트레스 시기 간의 각각의 자율신경계 관련 지수 변화를 보기 위해 paired t-test로 분석하였고, 성별 차이를 보기 위해 ANCOVA로 비교 분석하였다. 결 과: 안정 시기와 비교하여 기립 시기에서 SDNN, LF/ HF의 유의한 증가(p < 0.01) 및 NN50(p < 0.05), pNN50(p < 0.01)의 유의한 감소를 보였다. 안정 시기와 비교하여 스트레스 시기에서 SDNN (p < 0.01), RMSSD (p < 0.05) 유의한 증가를 보였다. 기립 시기와 비교하여 스트레스 시기에 SDNN, NN50, pNN50 지수가 유의하게 높은 결과를 보였다. 결 론: 기립 시기만 안정 시기와 비교하여 자율신경계 불균형과 관련된 LF/HF ratio의 유의한 상승을 보였으나, 정신적 스트레스와 안정 시기, 두 스트레스 간 LF/HF ratio의 차이는 보이지 않았다. 정신적 스트레스에 비해서 기립시기에서 SDNN, NN50 및 pNN50의 유의 한 증가하였다는 것은 우울증 환자들이 정신적 스트레스에 비해 신체적 스트레스에 보다 좀 더 민감하게 반응하는 경향이 있다는 것을 제시할 수 있다.

• Computers and Concrete
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• 제7권5호
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• pp.455-468
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• 2010

This paper presents a prediction and simulation method of tensile stress-strain curves of Engineered Cementitious Composites (ECC). For this purpose, the bridging stress and crack opening relations were obtained by the fiber bridging constitutive law which is quantitatively able to consider the fiber distribution characteristics. And then, a multi-linear model is employed for a simplification of the bridging stress and crack opening relation. In addition, to account the variability of material properties, randomly distributed properties drawn from a normal distribution with 95% confidence are assigned to each element which is determined on the basis of crack spacing. To consider the variation of crack spacing, randomly distributed crack spacing is drawn from the probability density function of fiber inclined angle calculated based on sectional image analysis. An equation for calculation of the crack spacing that takes into quantitative consideration the dimensions and fiber distribution was also derived. Subsequently, a series of simulations of ECC tensile stress-strain curves was performed. The simulation results exhibit obvious strain hardening behavior associated with multiple cracking, which correspond well with test results.

• Journal of Acupuncture Research
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• 제27권2호
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• pp.11-21
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• 2010

Objectives : We tried to investigate the effects of Carthami Semen(CF) pharmacopuncture and Bovis Calculus Fei Ursi(BU) pharmacopuncture on the heart rate variability(HRV) in adult men. As well as we tried to observe how CF pharmacopuncture and BU pharmacopuncture effect on the balance of the autonomic nervous system. Methods : We investigated on 40 healthy volunteers consisted of 20 subjects in CF pharmacopuncture group and 20 subjects in BU pharmacopuncture group respectively. We ruled out subjects whose vital sign isn't in normal range, yet they had taken a rest. The study established by a randomized, single-blind clinical trial. CF pharmacopuncture and BU pharmacopuncture was applied on each group. We measured HRV 7 times : baseline measurement and every 5 minutes for 30 minutes after injection. The SPSS 15.0 for Windows was used to analyze the data by the paired t-test(in group) and Independent sample t-test(between the groups). Results 1. After injection of CF pharmacopuncture, SDNN, Ln(TP), Ln(VLF) and Ln(LF) increased significantly, and Complexity, pNN50 decreased significantly. 2. After injection of BU pharmacopuncture, RMSSD, SDSD and HRV-index increased significantly. Conclusions : We suggest that CF pharmacopuncture activate sympathetic nervous system and BU pharmacopuncture tend to activate the autonomic nervous system.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1619-1624
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• 2007

The rainfall frequency estimations are critical in the design of hydraulic structures (such as bridges and culverts) to ensure that they are built economically and safely. In other words, they are not over designed or under designed. However one of the main assumptions in the creation of these analysis is that the rainfall data for a site is stationary. That is, climatic trends and variability in a region have negligible effects on the curves. But as has been proved in recent history, climatic variability and trends do exist and their effects on precipitation have not been negligible. Increasing occurrences of the El Nino phenomenon have lead to droughts and floods around the world, and long term trends in rainfall, both increases and decreases, have been seen in all regions across Korea. The purpose of this paper is to investigate and evaluate impacts of ENSO on rainfall characteries and rainfall frequency estimations in Korea. In this paper, The available rainfall data were categorized into Warm(EL Nino), Cold(La Nina), Normal episodes based on the Cold & Warm Episodes by Season then 50 years of daily rainfall data were generated for each episodic events(EL Nino, La Nina)

• 대한한의학회지
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• 제28권1호통권69호
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• pp.249-259
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• 2007

Objectives : We performed this study to analyze correlation among hair tissue minaral ratio, autonomic function and obesity. Methods : Subjects were gathered from January 2005 to March 2007. This study was carried out on 263 subjects who had visited Garosero oriental clinic and had no previous cardiovascular disease and thyroid disease. Heart rate variability (HRV) parameters, tissue mineral ratio and obesity degree were statistically compared with correlation and T-test analysis. Results : The results of this study are summarized as follows : 1. Normal group were predominant over obesity group in HRV parameters(SDNN, RMSSD, VLF, LF, HF). 2. Ca/P, Ca/K, Na/K and Fe/Cu, Na/Mg ratio in hair tissue mineral ratio have correlation with BMR, BMI and waist circumference. 3. Ca/P ratio has correlation with LF norm in HRV, and Na/K with HF, Na/Mg with LF, equally. Conclusions : Taken together these results may suggest that there are significant relationships between hair tissue mineral analysis and HRV.

• 대한한방내과학회지
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• 제32권4호
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• pp.473-486
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• 2011

Objectives : This study was designed to investigate the clinical characteristics and usefulness of comprehensive diagnosis of Yin-deficiency and heart rate variability in patients with burning mouth syndrome (BMS). Methods : We surveyed 30 burning mouth syndrome patients visiting the Oral Diseases Clinic of Kyung Hee University Oriental Medicine Hospital from April to September of 2011. The subjects were evaluated on self-assessed severity of burning mouth syndrome and xerostomia using visual analogue scale (VAS) score and Yin-deficiency condition (based on the 10-item Yin-deficiency questionnaire). Salivary function was measured by the unstimulated salivary flow rate (USFR), and heart rate variability (HRV) parameters were recorded by SA-2000E (Medicore Co., Ltd., Korea). Results : There were substantial significant positive correlations between burning sensation VAS scores in mouth and Yin-deficiency scores. There was significant negative correlation between xerostomia VAS score and USFR. Compared to the normal range of total power (TP) in HRV parameters, the burning mouth syndrome patients showed significant lower values of TP. Conclusions : The results of this study suggest that comprehensive diagnosis of Yin-deficiecny and HRV parameters are useful in diagnosing of burning mouth syndrome patients. Therefore, we assume that improvement of Yin-deficiency condition can be a potentially effective way to treat burning mouth syndrome.

• 대한약침학회지
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• 제11권1호
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• pp.41-54
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• 2008

Objective : In this study, we investigated the effects of Sweet Bee Venom(SBV) and Bee Venom(BV) at a acupoint, HT7(Shinmun) on the Heart Rate Variability(HRV) in the healthy man. And we tried to observe how Sweet Bee Venom and Bee Venom affects on the balance of the autonomic nervous system. Methods : We investigated on 22 heathy volunteers consisted of 10 subjects in SBV group and 12 subjects in BV group. Study form was a randomized, placebo-controlled, double-blind clinical trial. 22 subjects of each group were injected SBV and BV at HT7(Shinmun). And we measured HRV by QECG-3:LXC3203 (LAXTHA Inc. Korea) on 7 times : before and after injection per 5minutes during 30minutes. Results : 1. After SBV injection, Mean-RR was significantly high from 0 to 10 minutes, Mean-HRV was significantly low from to 10 minutes, SDNN was significantly high after 25minutes, Complexity was significantly high from 5 to 10 minutes and RMSSD was significantly high from 5 to 10minutes. 2. Complexity of SBV Group significantly decreased from 20 to 25minutes, RMSSD of SBV Group significantly increased from 10 to 15minute and from $20{\sim}25$minutes, SDSD of SBV Group significantly increased from 10 to 15 minute and from $20{\sim}25$minutes compared with that of BV group. 3. After SBV injection, Ln(VLF) was significantly from 25 to 30minutes. Conclusions : The results suggest that SBV in heathy adult man tend to activate the autonomic nervous system compared to BV within normal range.

• Journal of Acupuncture Research
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• 제29권5호
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• pp.127-137
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• 2012

Objectives : The purpose of this study is to review on current status of use and measurement condition of heart rate variability(HRV) by reviewing clinical studies published in journal of Korean medicine registered Korea citraion index(KCI). Methods : One hundred twenty articles were found by searching the representative Korean databases. At first analysis was performed by current status of use(journal, academic field of corresponing author, purpose of study, disease of subject, HRV measurement devices, intervention methods and tests compared to HRV). At second analysis was performed by measurement condition(uncontrolled study, relaxation before measurement, measurement position, measurement place, measurement time period and restriction of smoking, alcohol, caffeine, meal). Results : The analysis showed that department of acupuncture & moxibustion, department of oriental neuropsychiatry are major part in journal & academic field. The purpose of study were classified under studies to verify therapeutic effect on normal subject(39%), to verify therapeutic effect on the patients(8%), to investigate characteristics of the patients(34%) and to be compared with other test(19%). Disease of subject & measurement devices in article were so various. Major intervention methods were acupuncture(61.4%), mind-body intervention(19.2%). Studies that measurement condition were not controlled were relax time(24%), measurement position(19%), measurement place(26%), measurement time period(91%) and restriction of smoking, alcohol, caffeine, meal(49%). Conclusions : This study showed that current status of use of HRV is widespread in Korean medicine but more controlled measurement conditon are needed to get more reliable result from clinical studies and to improve diagnosis and treatment of Korean medicine.