• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.699-702
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• 2001

본 연구에서는 생활공간에서의 음 환경이 인체에 미치는 영향을 조사하기 위하여 긍정감성 유발 음환경으로서 시냇물 흐르는 소리를 배경으로한 명상음악을 제시하고 부정감성을 유발하는 음환경으로서 '헬리콥터소음'과 '마루삐그덕 소음'을 제시하여 자율신경계 생리반응으로서 심전도의 HRV를 분석하였다. HRV는 AR(autoregressive) 모델로 구하였으며 Power spectrum을 LF(0.01 - 0.08 Hz), MF(0.08 - 0.15 Hz), HF(0.15 - 0.5 Hz) 영역으로 나누어 LF. MF. HF 영역의 Power 및 LF/HF와 MF/(LF+HF) Power Ratio를 분석하였다.

• 한국초지조사료학회지
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• 제33권1호
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• pp.45-51
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• 2013

본 실험은 조사료와 농후사료비율(조:농비)에 따라 low forage(LF)구 및 high forage(HF)구로 나누어 Holstein 착유소(초산) 10두를 각 5두씩 배치하여 실시하였다. LF구는 조:농비가 37:63로 BIRG 사일리지와 혼합건초를 포함한 조사료의 급여량을 줄인 반면 농후사료를 다량 급여하였다. HF구는 조:농비가 62:38로 농후사료 급여량을 줄인 반면 BIRG 사일리지와 혼합건초를 포함한 조사료를 다량 급여하였다. 평균 조사료섭취량은 LF구 7.1 및 HF구 13.0 kg으로 HF구에서, 평균 농후사료 섭취량은 LF구 12.3 및 HF구 7.9 kg으로 LF구에서 유의적으로 높았다(p<0.05). 총 사료 섭취량은 LF구 19.4 및 HF구 20.9 kg으로 HF구에서 높은 경향을 보였으나 유의적인 차이는 없었다(p>0.05). CP, TDN 및 NEL 섭취량은 두 처리구간에 유의적인 차이는 없었다(p>0.05). 실제 산유량은 LF구 26 및 HF구 23.9 kg/d 으로 처리 간에 유의적인 차이는 없었으나(p>0.05) LF구에서 높은 경향을 보였다. 4% FCM은 LF구 22.8 및 HF구 22.3 kg/d 으로 유의적인 차이는 없었다(p>0.05). HF구에서 유지방 함량은 높고 MUN 함량은 낮았다. 우유의 C14:0, C16:0 및 C16:1n7 함량은 HF구가 LF구 보다 유의적으로 높았으나(p<0.05), 그 외의 우유지방산은 두 처리구간에 차이는 없었다. 이상의 결과로부터 본 연구에서와 같이 급여 사료 중 BIRG 사일리지와 수입건초와 같은 조사료를 적절하게 배합하여 다량급여 하여도 착유소(초산우)에 필요한 영양소 충족이 가능하여 산유량의 감소가 없는 것으로 사료된다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권8호
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• pp.2068-2082
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• 2023

With the rapid development of deep learning, Depth Map Super-Resolution (DMSR) method has achieved more advanced performances. However, when the upsampling rate is very large, it is difficult to capture the structural consistency between color features and depth features by these DMSR methods. Therefore, we propose a color-image guided DMSR method based on iterative depth feature enhancement. Considering the feature difference between high-quality color features and low-quality depth features, we propose to decompose the depth features into High-Frequency (HF) and Low-Frequency (LF) components. Due to structural homogeneity of depth HF components and HF color features, only HF color features are used to enhance the depth HF features without using the LF color features. Before the HF and LF depth feature decomposition, the LF component of the previous depth decomposition and the updated HF component are combined together. After decomposing and reorganizing recursively-updated features, we combine all the depth LF features with the final updated depth HF features to obtain the enhanced-depth features. Next, the enhanced-depth features are input into the multistage depth map fusion reconstruction block, in which the cross enhancement module is introduced into the reconstruction block to fully mine the spatial correlation of depth map by interleaving various features between different convolution groups. Experimental results can show that the two objective assessments of root mean square error and mean absolute deviation of the proposed method are superior to those of many latest DMSR methods.

• Journal of Acupuncture Research
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• 제28권2호
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• pp.27-41
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• 2011

Objectives : The aim of this study was to examine the effect of manual acupuncture at the bilateral $LI_4$, $ST_{36}$ and $LR_3$ on normal human every 3 minute time interval by using power spectrum analysis. Methods : 25 healthy volunteers participated in this study. 32 channel EEG(Electroencephalogram) measurements were carried out before, during and after acupuncture treatments. In this study, power spectrum was used as a measure of complexity. Statistical analysis was performed using repeated measure ANOVA and Bonferroni method. Results : 1. In acupuncture group, Mean HRT, PSI, Normalized HF decreased significantly. SDNN, Ln(TP), Ln(LF), Ln(VLF), Normalized LF and LF/HF ratio increased significantly. RMSSD, Ln(HF) were not affected. 2. In sham acupuncture group, all indicators were not affected. 3. In control group, mean HRT, Ln(TP) decreased significantly. SDNN, RMSSD, PSI, Ln(LF), Ln(HF), Ln(VLF), normalized LF, normalized HF and LF/HF ratio were not affected. Conclusions : This results suggest that manipulation needling of 6 acupoints induced increase of delta, theta, beta waves. Both manipulation and simple needling induced decrease of alpha wave during 12~15 time intervals.

• 한국안전학회지
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• 제30권2호
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• pp.56-62
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• 2015

The purpose of this study was to identify the relationship between the index of Electrocardiography(LF/HF) and the occurrence of drowsiness driving while driving in a simulated situation. Participants were 31 undergraduate students with an experience in driving and they participated 30 minutes driving under enough sleep condition and 1 hour under the sleep deprivation condition. The Euro Truck Simulator II was used for driving simulation task and ECG and perceived drowsiness of each participants were measured during two driving conditions. Perceived sleepiness recorded by the checklist every 10 minutes and ECG data extracted before and after 15 seconds of every 10 minutes to verify the relationship between two variables. The results showed that the level of perceived sleepiness under sleep deprivation condition was higher than that under the enough sleep condition, and the level of LF/HF under sleep deprivation condition was lower than that under the enough sleep condition. In addition, the result of analysis of repeated measure ANOVA for ECG indicated that authentic sleepiness revealed in 20 minutes after the start of driving under the sleep deprivation condition. However, the result of perceived drowsiness indicated that authentic sleepiness revealed in 30 minutes after the start of driving. These result suggest that the time difference between biological and perceived response on drowsiness may be exist. Finally, the significant negative correlation between the LF/HF level and perceived drowsiness was observed. These findings suggest that ECG(LF/HF) can be an possible index to measure drowsiness driving.

• The Korean Journal of Physiology and Pharmacology
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• 제3권6호
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• pp.605-613
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• 1999

The purpose of the present study was to evaluate cardiovascular regulation during passive standing (PS) after ethanol ingestion by spectral analysis of heart rate variability (HRV) in flushed and nonflushed subjects. Of 24 young male subjects, 8 belonged to flushed group (F) and 16 to nonflushed group (NF). Two sessions of 10-min PS were performed before and after ethanol (0.5 g/kg) ingestion. Powers of R-R interval variability in very low frequency $(VLF,\;0{\sim}0.05\;Hz),$ low frequency $(LF,\;0.05{\sim}0.15\;Hz)$ and high frequency $(HF,\;0.15{\sim}0.50\;Hz)$ bands, normalized powers (LFn and HFn) and LF/HF ratio were obtained. After ethanol ingestion, F showed higher heart rate than NF. PS increased LFn $(+22.9{\pm}3.6\;in\;NF,\;+12.8{\pm}4.7$ in F, in normalized units) and LF/HF $(+3.10{\pm}0.57\;in\;NF,\;+3.00{\pm}1.08\;in\;F)$ and decreased HFn powers. Ethanol ingestion increased LFn and LF/HF and decreased HFn. PS after ethanol resulted in higher LFn and LF/HF and lower HFn than the prior PS. F showed a greater and more sustained HRV change than NF after ethanol. In conclusion, PS or ethanol ingestion increased LFn and LF/HF and decreased HFn. Flushed subjects showed an accentuated HRV response to ethanol.

• Journal of Acupuncture Research
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• 제24권5호
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• pp.1-12
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• 2007

목적 : 양심안영(養心安營), 청신녕지(淸神寧志), 조리기혈(調理氣血)의 효능을 가진 심유혈(心兪穴)($BL_{15}$)이 자율신경의 안정에 기여할 수 있다는 것을 입증하기 위하여 객관적으로 자율신경의 활성과 심장의 많은 연관성이 있다고 알려진 HRV(Heart Rate Variability)를 이용하였다. 방법 : 안정을 취한 후 29명의 남자 대상자를 HRV가 먼저 측정하였다. HRV 측정 후 대상자의 량측(兩側) 심유혈(心兪穴)에 자침하고 전침으로 지속적인 자극을 주었으며, 15분간 이 상태로 류침(留鍼)하였다. 발침(拔鍼) 후 다시 HRV를 측정하여 이를 측정 전과 비교하였다. 측정 결과의 비교 항목은 MHRT, SDNN, RMSSD, TP, VLF, LF, HF, Norm LF, Norm HF, LF/HF ratio로 하였다. 결과 : MHRT는 유의성이 있었다. SDNN은 유의성이 없었다. RMSSD는 증가하였으나, 유의성이 없었다. TP는 감소하였으나, 유의성이 없었다. VLF는 감소하였으나, 유의성이 없었다. LF는 감소하였으나, 유의성이 없었다. HF는 증가하였으나, 유의성은 없었다. Norm LF는 감소하였으나, 유의성이 없었다. Norm HF는 증가하였으나, 유의성은 없었다. LF/HF ratio는 감소하였으나, 유의성이 없었다. 결론 : 심유혈(心兪穴) 자침 결과는 교감 신경의 흥분을 가라앉히고 부교감 신경의 안정성을 증대하여, 심장의 안정도에 기여하는 것으로 보이나, 이는 통계적으로 의미가 없었다. 본 연구의 대상 집단이 소규모이며 스트레스가 아주 심하지 않은 집단이라는 점에서 유의성이 상대적으로 부각되지 못했다. 향후 비교할 만한 대조군을 설정하여 더 심한 스트레스를 받은 큰 집단을 대상으로 한 연구가 필요할 것으로 사료된다.

• 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.

• 대한통합의학회지
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• 제7권4호
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• pp.161-170
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• 2019

Purpose : This study aimed to investigate the effects of a thoracic flexibility exercise program on pain, heart rate variability (HRV), and depression in patients with chronic low back pain. Methods : Fifty patients with chronic low back pain participated in this study. Each participant performed a pre-test and post-test. The outcome measures evaluated were a visual analog scale, HRV test results (automatic activity, standard deviation normal to normal [SDNN], low frequency [LF], high frequency [HF], and LF/HF ratio), and the Beck Depression Inventory. Patients underwent conventional physiotherapy for 35 minutes per session. In addition, a thoracic flexibility exercise program (trunk rotation exercise, McKenzie exercise, and supine thoracic extension exercise) were performed 3 times per week for 4 weeks. Results : After the training period, the visual analog scale results showed a significant decrease in the post-test compared to the pre-test. Automatic activity, SDNN, LF, HF, and LF/HF ratio significantly increased in the post-test compared to the pre-test. The Beck depression inventory results significantly decreased in the post-test compared to the pre-test. Conclusion : This study demonstrated that a thoracic flexibility exercise program improves a visual analog scale, HRV (automatic activity, SDNN, LF, HF, and LF/HF ratio), and the Beck Depression Inventory in patients with chronic low back pain.

• 전기전자학회논문지
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• 제24권1호
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• pp.170-177
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• 2020

본 논문은 HF/LF 변조 방법을 적용한 ANPC (active neutral point clamped) 인버터의 스위치 개방 고장에 대응하기 위한 허용 제어 방법을 제안한다. 기존 Si 기반 인버터에 비해 SiC MOSFET과 Si IGBT로 구성된 ANPC 인버터는 시스템의 효율이 높고 출력 품질이 우수하다. HF/LF 변조는 커뮤테이션 루프를 줄일 수 있어 MW 급 대용량 인버터를 위해 사용되는 변조 기법이다. MW 급 인버터의 스위치 개방 고장은 부하에 심각한 손상을 입히며, 인버터가 동작을 멈출 경우 막대한 경제적 손실을 야기한다. 제안하는 스위치 개방 고장의 허용 제어 기술은 ANPC 인버터의 지속적인 운전을 가능하게 하며 신뢰성을 향상 시킨다. 제안하는 기법의 성능은 시뮬레이션 결과를 통해 검증한다.