당뇨병 환자의 자율신경병증 평가에 있어 24 시간 Holter Monitoring 을 이용한 Power Spectrum 의 Diurnal Variation 에 대한 연구

박순희(Sun Hee Park),박종욱(Chong Wook Park),김정식(Jeong Sik Kim),곽현철(Hyun Cheol Kwak),김광석(Kwang Suck Kim),오성주,김수길,원동준(Dong Jun Won),박정식(Jeong Sik Park) 대한내과학회 1997 대한내과학회지 Vol.53 No.4

Objective: We studied the efficacy of the power spectral and nonspectral analysis and its diurnal variations for the early detection of the diabetic autonomic neuropathy. Method: The spectral and nonspectral analysis of 24hour-Holter monitoring were done for both diabetic neuropathy patients and controls. We also made a comparative analysis of the diurnal variations between the patient and control groups by means of hourly power spectral analysis. Result: 1) The power spectral density of the diabetic neuropathy patients was below than that of the normal controls (P<0.05) (Table 2, Fig. 1). 2) The nonspectral analysis of the diabetic neuropathy patients was below than that of the normal controls except for the mean RR intervals (P<0.05) (Table 3). 3) Every hour-power spectral analysis showed a diurnal variation of day time (06:00 to 16:00) decrease in high frequency area of the normal controls. On the contrary, there was a disappearance of the diurnal variation in patient group. Conclusion: The power spectral and nonspectral analyses after 24hour-Holter monitoring and its diurnal variation in the diabetic patients are considered as good means of the early detection of autonomic neuropathy, but further study of its diagnostic value will be needed.

정상뇌파의 스펙트럼 분석

최경규 대한신경과학회 1999 대한신경과학회지 Vol.17 No.3

Differences between Physostigmine- and Yohimbine-induced States Are Visualized in Canonical Space Constructed from EEG during Natural Sleep-wake Cycle in Rats

이만기,김민지,노무택,장일성,원승희 한국뇌신경과학회 2011 Experimental Neurobiology Vol.20 No.1

Although quantitative EEG parameters, such as spectral band powers, are sensitive to centrally acting drugs in dose- and time-related manners, changes of the EEG parameters are redundant. It is desirable to reduce multiple EEG parameters to a few components that can be manageable in a real space as well as be considered as parameters representing drug effects. We calculated factor loadings from normalized values of eight relative band powers (powers of 0.5, 1.0∼2.0, 2.5∼4.0, 4.5∼5.5, 6.0∼8.0, 8.5∼12.0, 12.5∼24.5, and 25∼49.5 Hz bands expressed as ratios of the power of 0.5-49.5 Hz band) of EEG during pre-drug periods (11:00∼12:00) by factor analysis and constructed a two-dimensional canonical space (reference canonical space) by canonical correlation analysis. Eight relative band powers of EEG produced by either physostigmine or yohimbine were reduced to two canonical scores in the reference canonical space. While changes of the band powers produced by physostigmine and yohimbine were too redundant to describe the difference between two drugs, locations of two drugs in the reference canonical space represented the difference between two drug's effects on EEG. Because the distance between two locations in the canonical space (Mahalanobis distance) indicates the magnitude of difference between two different sets of EEG parameters statistically, the canonical scores and the distance may be used to quantitatively and qualitatively describe the dose-dependent and time-dependent effects and also tell similarity and dissimilarity among effects. Then, the combination of power spectral analysis and statistical analysis may help to classify actions of centrally acting drugs.

일반인구의 심박동수 변이의 결정인자들

전형준,김상섭,성지동,백도명 대한순환기학회 2001 Korean Circulation Journal Vol.31 No.1

출혈성 쇽 환자에서 Power Spectral Analysis를 이용한 심박수 변이도 분석의 의의

김승호,이한식,윤유상,김유선,정상원,지훈상 대한응급의학회 2000 대한응급의학회지 Vol.11 No.1

Background. Recently, with the advent of the chaos theory and computer technology, physicians could analyze the heart rate variability(HRV) which reflects autonomic control of cardiovascular system. The power spectral analysis(PSA) in frequency domain provided valuable informations on cardiac disorders and autonomic diseases. In compensatory phase of hemorrhagic shock, autonomic nervous system plays major role in maintaining near-normal hemodynamic to preserve tissue perfusion. In this thesis, the clinical feasibility of HRV as a new tool for the assessment of severity and responsiveness to treatment during early phase of hemorrhagic shock was studied. Methods. The PSA of HRV was performed using fast Fourier transformation algorithm with 512 RR interval data recorded off-line by Holter system. Each components of PSA were compared between patient and control group, each consisted of 19 patients. Results. On presentation to emergency department, the patient group showed significantly lower very low frequency(VLF) band, low frequency(LF) band, high frequency(HF) band, low frequency normalized unit(LFnu) and high frequency normalized unit(HFnu) than control group. After stabilized, LF and LFnu decreased in the patient group compared to initial phase but there was no statistical significance. As fluid resuscitation started and continued, LF/HF ratio increased and then stabilized thereafter, In one full recovered patient, LF/HF ratio obtained during one hour period on the 20th hospital day showed very unstable and dynamic change which may represent homeodynamic rather homeostasis. Conclusion. The PSA of HRV seemed to be potential tools in the diagnosis and monitoring of hemorrhagic shock. Well-designed further studies are expected for the refinement in data processing and interpretation of results of PSA of HRV.

자율신경계의 활성도 측정을 위한 Data Acquisition System의 개발 및 임상응용

신동구,박종선,김영조,심봉섭,이상학,이준하 영남대학교 기초/임상의학연구소 2001 Yeungnam University Journal of Medicine Vol.18 No.1

Background: Power spectrum analysis method is a powerful noninvasive tool for quantifying autonomic nervous system activity. In this paper, we developed a data acquistion system for estimating the activity of the autonomic nervous system by the analysis of heart rate and respiratory rate variability using power spectrum analysis. Materials and methods: For the detection of QRS peak and measurement of respiratory rate from patient's ECG, we used low-pass filter and impedance method respectively. This system adopt an isolated power for patient's safety. In this system, two output signals can be obtained: R-R interval(heart rate) and respiration rate time series. Experimental ranges are 30∼240 BPM for ECG and 15∼80 BPM for respiration. Regults: The system can acquire two signals accurately both in the experimental test using simulator and in real clinical setting. Conclusion: The system developed in this paper is efficient for the acquisition of heart rate and respiration signals. This system will play a role in research area for improving our understanding of the pathophysiologic involvement of the autonomic nervous system in various disease states.

풍직각방향과 비틀림방향의 응답상관을 고려한 풍하중 조합

김원술(Kim, Wonsul),김용철(Kim, Yong Chul) 대한건축학회 2015 大韓建築學會論文集 : 構造系 Vol.31 No.4

The wind tunnel test was conducted to investigate characteristics of fluctuating wind forces acting on tall buildings for various side ratios (D/B=1.0, 1.1, 1.2, 1.3, 2.0 and 3.0) and different terrain roughnesses. Further, the wind load combination was examined by the correlation of the displacement response between acrosswind and torsional directions through Spectral Modal Analysis Method and Time History Analysis Method. As a result, there was no significant effect of the changing of terrain roughnesses on fluctuating moment coefficients for acrosswind and torsional directions, but they were varied with the changing of wind directions. Acrosswind overturning moment coefficients were highly correlated with the torsional moment coefficient with the increase in wind directions. The response and correlation obtained by Time History Analysis were good agreement with those of Spectral Modal Analysis. Also, the response correlation between acrosswind and torsional directions was highly affected by natural frequency ratios. Hence, the wind load combination for acrosswind and torsional directions shall be considered that when the natural frequencies between acrosswind and torsional directions are close to each other.

Relative Spectral Power Analysis of EEG Activity during Actions Involving Number Sense and Spatial Ability

김지선 대한수학교육학회 2019 수학교육학연구 Vol.29 No.4

Number sense and spatial ability are key components of mathematical abilities. Of late, brain imaging techniques have been used with the aim of identifying definite areas of the brain responsible for processing number sense and spatial ability. The current study analyzes brain waves that are activated while the subjects are performing number sense and spatial ability tasks. Particularly, each band of brainwave captured by electroencephalography (EEG) is assessed using relative spectral power analysis. The results did not highlight the differences between the average values obtained for the number sense tasks and spatial ability tasks; however, there were statistically significant differences in values for various subtypes of the task problems. In the case of theta wave analysis, number sense task 2(NS2) was found to cause more intense theta wave than number sense task 3(NS3). Conversely, alpha wave did now show significant differences in activity levels for the different brain areas and task types. Task spatial ability task 1(SA1) caused a higher beta wave activity compared to spatial ability task 2(SA2), which in the current study is interpreted as the effect of the subjects having become more familiar with the tasks. In regards to the two types of tasks, beta wave tended to be activated more in the right parietal lobe, which is associated with number sense and spatial ability. Gamma wave was more activated by NS3 than by NS2 and spatial ability task 3(SA3), and resulted to the right parietal lobe being more activated. The EEG analysis demonstrated that the same type of tasks does not activate brain waves to an equal extent. The results of the current study may be used to initiate a neurocognitive approach to research on the challenges that the students experience when learning mathematics, thereby building a foundation for solving this problem.

진동 환경에서 감시장치 적외선 가시광 경통 간 변위 간섭 유무의 해석적 확인

송아영(Ah-Young Song),권병오(Byung-Oh Kwon),한대희(Dae-Hee Han),정현수(Hyun-Su Jung),정혜진(Hye-Jin Jung),임성환(Sung-Hwan Yim) 한국소음진동공학회 2020 한국소음진동공학회 논문집 Vol.30 No.2

The displacement characteristics of infrared and visible light camera barrels in military reconnaissance equipment are analyzed. It is difficult to perform the test with a measurement acceleration sensor because of the structural characteristics of the barrel. It is also challenging to secure the stability of the barrel only by analysis. Therefore, the test is conducted in a structure without a barrel. After the test, the vibration analysis is performed, and the results of the test and analysis are compared and analyzed. When the comparative analysis is completed, vibration analysis is performed by modeling the barrel on the test model. Through the results, the displacement characteristics of the barrels are analyzed to confirm the structural stability of the product.

주파수 영역에서의 기계 구조물의 피로수명 예측

박장수(Jangsoo Park),이재원(Jayone Lee),이성범(Seong Beom Lee),김흥섭(Heungseob Kim) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5

The purpose of this paper is to compare with estimation of equivalent fatigue load in time domain and frequency domain. The fatigue analysis for random loads is discussed in several papers. In general, Equivalent fatigue load in time-domain is estimated by rainflow cycle counting. In case of frequency domain, it can estimate through probability density function of Dirlik`s method that directly use power spectrum density of stress. Probability density function of Dirlik`s method is function of spectral moment only. For verification of performance with two methods, simulations is performed with general random signal and FEM analysis.