• 대한물리의학회지
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• 제10권1호
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• pp.37-43
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• 2015

PURPOSE: The purpose of this study is to investigate the effect of the physical therapy treatment room environment using microwave diathermy on the autonomic nervous system of human body. METHODS: Participants were 24 healthy adults. Standard deviation of all normal R-R intervals(SDNN), root mean square of successive differences(RMSSD), low frequency(LF), high frequency(HF), LF/HF ratio were compared in microwave irradiation and non-irradiation group. Data were analyzed in Wilcoxon's signed-ranks test and Mann-Whitney U test. RESULTS: Standard deviation of all normal R-R intervals (SDNN), root mean square of successive differences (RMSSD), low frequency(LF), high frequency(HF), LF/HF ratio were not significantly different in microwave irradiation group. Standard deviation of all normal R-R intervals(SDNN), root mean square of successive differences (RMSSD), low frequency(LF), high frequency(HF), LF/HF ratio were not significantly different in microwave non-irradiation group. Standard deviation of all normal R-R intervals(SDNN), root mean square of successive differences (RMSSD), low frequency(LF), high frequency(HF), LF/HF ratio were not significantly different between two groups. CONCLUSION: There was no significant change in the sympathetic nervous system and parasympathetic nervous system regardless of the presence of microwave irradiation. There was no significant change in the autonomic nervous system adaptability regardless of the presence of microwave irradiation.According to this study, microwave diathermy does not have significant effect on the autonomic nervous system.Future study is necessary to investigate the long term effect of the physical therapy treatment room environment using microwave diathermy on the autonomic nervous system of the human body.

• Wind and Structures
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• 제11권2호
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• pp.137-152
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• 2008

This paper discusses engineering aspects of the rear-flank downdraft that was recorded near Lubbock, Texas on 4 June 2002, and produced a gust wind speed nearly equal to the design value (50-year return period) for the region. The general characteristics of the storm, and the decomposition of the time histories into deterministic 'running mean' and random turbulence components are discussed. The fluctuating wind speeds generated by the event can be represented as a dominant low-frequency 'running mean' with superimposed random turbulence of higher frequencies. Spectral and correlation characteristics of the residual turbulence are found to be similar to those of high-frequency turbulence in boundary-layer winds. However, the low-frequency components in the running-mean wind speeds are spatially homogeneous, in contrast to the low-frequency turbulence found in synoptic boundary-layer winds. With respect to transmission line design, this results in significantly higher 'span reduction factors'.

• 대한의용생체공학회:의공학회지
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• 제11권2호
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• pp.195-202
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• 1990

The hypothesis of asymmetric resistance to explain the phenomenon of lung hyperinflation (LHI) during hlgh frequency ventilation (HFV) was quantitatively studied. LHI was predicted by modeling the ism-volume pressure-flow (IVPF) data from 5 human subjects using the empirical Rohrer's equation. Non-steadiness during HFV was compensated by em- ploying recently proposed volume-frequency diagram. Tidal volume and ventilation frequency were 100 ml and 20 Hz, respectively. Airflow pattern was a symmetric sinusoid. The predic- tion results of mean pressure drop across the airways were averaged for those 5 subjects, and compared with zero by one-sided student's t-test. A marginally significant (P<0.1) increase in mean pressure drop was observed during HFV at low lung volumes (below FRC) , which could increase mean lung volume up to one liter When the lung volume was above FRC, no significant LHI (P >0.25) was resulted. LHI seemed to be inversely related to the lung volume. These results recommend to clinically apply HFV only at lung volumes above FRC.

• 환경영향평가
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• 제15권3호
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• pp.207-215
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• 2006

The purpose of this paper is to analyze the spatial distribution and change of the frequency of Yellow Sand days and to examine their relationship with atmospheric circular characteristics at the surroundings of the Korean peninsula. Yellow Sand days data are used by intensity, Siberian High Index and monthly mean temperature of the Northern Hemisphere. In the Middle-western region, the occurrence frequency of Yellow Sand days was higher during the study period (1973-2004). Also, the occurrence frequency of Yellow Sand days increased to latter half 16 years compared with the first half 16 years, and be clearer in Middlewest regions. Yellow Sand days frequency increased, and the trend was distinct in the Jungbu region during the study period. Increasing trend of Yellow Sand days frequency was significant for the recent 22 years. Yellow Sand days had a negative relationship with Siberian High Index in February and March. Therefore, Siberian High Index became weaker in the spring, and possibility for the occurrence of Yellow Sand days was generating larger. Yellow Sand days had a positive relationship in monthly mean temperature of the Northern Hemisphere. Especially, the case of the strong Yellow Sand days is significant. Recently, global warming might be affecting the occurrence of strong Yellow Sand days.

• Journal of information and communication convergence engineering
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• 제8권2호
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• pp.159-162
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• 2010

This paper presents a new Kurtosis driven Variable Step-Size Normalized Least Mean Square (KVSSN-LMS) algorithm to prevent repeater from oscillation due to feedback signal of radio frequency (RF) repeater. To get better Mean Square Error (MSE) performance, step-size is adjusted using the kurtosis. The proposed algorithm shows the better performance of steady state MSE. The proposed algorithm shows a better ERLE performance than that of KVSS-LMS, VSS-NLMS, NLMS algorithms.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2120-2125
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• 2005

The principal idea of vibration isolation is to filter out the response of the system over the corner frequency. The isolation objectives are to transmit the attitude control torque within the bandwidth of the attitude control system and to filter all the high frequency components coming from vibration equipment above the bandwidth. However, when a reaction wheels or control momentum gyros control spacecraft attitude, vibration inevitably occurs and degrades the performance of sensitive devices. Therefore, vibration should be controlled or isolated for missions such as Earth observing, broadcasting and telecommunication between antenna and ground stations. For space applications, technicians designing controller have to consider a periodic vibration and disturbance to ensure system performance and robustness completing various missions. In general, past research isolating vibration commonly used 6 degree order freedom isolators such as Stewart and Mallock platforms. In this study, the vibration isolation device has 3 degree order freedom, one translational and two rotational motions. The origin of the coordinate is located at the center-of-gravity of the upper plane. In this paper, adaptive notch filter finds the disturbance frequency and the reference signal in filtered-x least mean square is generated by the notch frequency. The design parameters of the notch filter are updated continuously using recursive least square algorithm. Therefore, the adaptive filtered-x least mean square algorithm is applied to the vibration suppressing experiment without reference sensor. This paper shows the experimental results of an active vibration control using an adaptive filtered-x least mean squares algorithm.

• 대한통합의학회지
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• 제4권4호
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• pp.77-82
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• 2016

Purpose: The purpose of this study was to investigate the therapeutic effect of non-invasive vagus nerve stimulation by transcutaneous electrical nerve stimulation application on the autonomic nervous system of human body. Methods: Participants were seventeen healthy adults. Standard deviation of all normal N-N intervals(SDNN), root mean square of successive differences(RMSSD), low frequency(LF), high frequency(HF) were compared in pre and post Mean values after intervention. Data were analyzed in Wilcoxon's signed-ranks test. Results: The results of this study is that sistolic blood pressure and pulse rate decreased mean value after non-invasive vagus nerve stimulation by transcutaneous electrical nerve stimulation. High frequency, low frequency, SDNN, RMSSD increased mean value in heart rate variability after intervention. But that is not significant except for SDNN. Conclusion: Non-invasive vagus stimulation by transcutaneous electrical nerve stimulation effect on parasympathetic nerve stimulation, and then it might be effective method for autonomic nerve balance control.

• 대한전자공학회논문지TC
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• 제42권12호
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• pp.77-84
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• 2005

OFDM(Orthogonal Frequency Division Multiplexing) 및 SC-CP(Single Carrier with Cyclic Prefix) 방식은 문선 분야에서 각기 각광받고 있으며, 두 방식 모두 주파수 영역에서 효율적인 등화를 수행할 수 있는 장점을 지니고 있다. 무선 채널의 도플러 쉬프트 현상이 수반되는 경우 등화기만으로 온전히 왜곡 보상이 여의치 않을 수 있으며, 이에 따라 위상에러 추적회로와 등화기를 연동시켜 성능 향상을 도모할 수 있다. 본 논문에서는 평균위상에러의 효과를 기술하였고, 결정지향 방식의 평균위상 에러 추적회로와 proportional 등화기를 연동한 성능을 설계하였다. 아울러 시뮬레이션 결과를 통해 시스템의 성능 저하를 최소화하면서 추적회로의 연산 부담을 줄일 수 있음을 제시하였다.

• 한국수자원학회논문집
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• 제49권7호
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• pp.599-606
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• 2016

본 연구에서는 남한강 유역내 충주댐 직하류부터 양평 수위관측소 지점까지 댐의 영향을 받는 지역에 대해 저류함수모형을 이용하여 댐에 의해서 조절되지 않은 자연상태의 홍수량을 모의하고, 이를 근거로 홍수빈도분석을 실시하여 기본홍수량의 거동 특성을 분석하였다. 충주댐 하류부 6지점에 대한 지점빈도해석을 통해 산정한 재현기간에 따른 분위수의 변화는 지점별로 서로 유사하였고, 이의 평균적인 거동은 지역빈도분석 결과와 거의 일치하였다. 충주댐 하류지역 자연홍수량에 대해 계산된 분위수 및 빈도홍수량의 평균치는 충주댐 상류에서 기 도출된 결과와 유사한 특성을 나타내었다. 충주댐 하류지역의 분위수와 빈도홍수량의 평균치는 댐 유무에 따라 큰 차이를 나타내었으며, 특히 분위수는 재현기간이 커짐에 따라 더욱 큰 편차를 보였고, 통제된 경우 빈도홍수량의 평균치는 댐 하류로 갈수록 기본홍수량에 점차 근접해가는 형태를 나타내었다.

• 한국응급구조학회지
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• 제12권2호
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• pp.5-26
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• 2008

Purpose : This study was performed to develop the curriculum of Emergency Medical technology of College. Method : The authors analyzed curricular of EMT in 12 college in Korea. We conducted the distribution, credit, mean, frequency of liberal arts, majors, teaching profession subject by Kim and Lee(2007). We compared curriculum of knowledge and clinical training courses. Results : The numbers of whole subjects were 59.3 and the number of mean and the credits were 130.8 degree of mean. The numbers of liberal arts were 9.5 number of mean and the credits were 15.5 degree of mean. The numbers of major were 47.5 number of mean and the credits were 111.4 degree of mean. The numbers of teaching profession subject were 1.9 number of mean and the credits were 4 degree of mean. Finally, frequency of curriculum of knowledge and clinical training courses were 57.1% and 42%, respectively. Conclusion : This results will represent curriculum development and will standardize curriculum for EMT collage. in addition, it will make EMT curriculum standardized.