• 한국전문물리치료학회지
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• 제12권1호
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• pp.111-119
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• 2005

The purpose of this study was to compare the differences of hip and thigh muscle activities between subjects with increased and decreased femoral anteversion during stair ascent. Twelve healthy female volunteers participated in this study. The subjects were divided into two groups (group 1 with increased anteversion of the hip, group 2 with decreased anteversion of the hip). This study analyzed differences in each mean peak gluteus maximus (GM), gluteus medius (GD) and tensor fascia lata (TLF) EMG amplitude: composite mean peak hip muscles (GM, GD, TFL) EMG amplitude ratios and in each mean peak vastus medialis oblique (VMO), vastus lateralis (VL), biceps femoris (HM) and semitendinosus (HL) EMG amplitude: composite thigh muscles (VMO, VL, HM, HL) EMG amplitude ratios among subjects with decreased or increased relative femoral anteversion. EMG ratios were compared in the stance and swing phase of stair ascent. Group 1 showed an increased standardized mean GM and GD EMG amplitude and decreased standardized mean TFL to composite mean hip muscles EMG amplitude ratios in stair ascent during both stance and swing phase. Also, group 1 showed an increased standardized mean HL EMG amplitude and decreased standardized mean VL and HM to composite mean thigh muscles EMG amplitude ratios in stair ascent during both stance and swing phases. There was no statistically significant difference in vastus medialis oblique between subjects with increased or decreased relative femoral anteversion. In order to provide rehabilitation professionals with a clearer picture of the specific requirements of the stair climbing task, further research must be expanded to include a wider range of age groups that represent the general public, such as including middle-aged healthy persons.

• 산업경영시스템학회지
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• 제35권3호
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• pp.103-109
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• 2012

The purpose of this paper is to suggest the strategical lifting postures able to alleviate imbalanced EMG amplitude leading to an increase in low back muscle fatigue while lifting asymmetric load dynamically. Eleven male subjects are required to lift symmetrically an external load with 15.8kg and load center of gravity (LCG) deviated 10cm to the right from the floor to the waist height at the speed of about 25cm/sec. The EMG amplitudes on bilateral low back muscles (Longissimus, Iliocostalis, and Multifidus) are recorded during 2sec and analyzed. Independent variables are trunk postures (No bending vs. Bending to the LCG) and feet placements (Parallel vs. Right foot in front of the other vs. Right foot behind the other). Dependent variables are EMG amplitude average on six muscles and the EMG amplitude difference between right and left muscle group. Results indicate the phenomenon showing an amplitude increase in the left muscle group is equal to an decrease in the right one is observed in dynamic as well as static lifts, bending the trunk to the LCG increases amplitude discrepancy more than no trunk bending, and the amplitude discrepancy in one foot ipsilateral to LCG in front of the other foot is lowest among other foot postures. As bilateral EMG amplitude discrepancy increases total low back muscle fatigue, the strategical combination of no trunk bending and one foot close to LCG in front of the other is recommended for preventing elevated incidence of low back pain (LBP).

• 생물정신의학
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• 제16권3호
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• pp.181-189
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• 2009

Objectives : N100 amplitude slope(the intensity dependence of the cortical auditory evoked potentials) is widely considered as an indirect indicator of central serotonergic neurotransmission. However, there are only a few studies about N100 amplitude slopes of major psychiatric disorders. In this study, we examined N100 amplitude slope differences among major depressive disorder(MDD), bipolar disorder(BD), schizophrenia (SCZ) and normal controls(NC). Methods : We measured the N100 amplitude slopes of 35 patients with MDD, 33 patients with BD, 27 patients with SCZ and 35 NC subjects. Amplitude differences from N1 to P2 at the five different sound intensities(55, 65, 75, 85 and 95dB) were examined at Cz electrode. The N100 amplitude slope was calculated as the linear regression of five N1/P2 peak-to-peak amplitudes across stimulus intensities. Results : BD patients showed significantly reduced N100 amplitude slope compared with NC(0.54${\pm}$0.70 vs. 0.96${\pm}$0.72, p=0.035). N100 amplitude slope of SCZ patients was significantly reduced compared with NC(0.50${\pm}$0.47 vs. 0.96${\pm}$0.72, p=0.027). N100 amplitude slope of BD patients was significantly lower than that of MDD patients(0.54${\pm}$0.70 vs. 0.94${\pm}$0.60, p=0.046). SCZ patients also showed significant reduction of N100 amplitude slope compared with MDD patients(0.50${\pm}$0.47 vs. 0.94${\pm}$0.60, p=0.036). There was no significant difference of N100 amplitude slope between MDD patients and NC(0.94${\pm}$0.60 vs. 0.96${\pm}$0.72, p=1.000). Conclusion : Interestingly, the N100 amplitude slopes of BD and SCZ were reduced compared to NC and MDD patients. Our results suggest the predictive use of N100 amplitude slope in making differential diagnoses of major psychiatric disorders. Clinical implications of N100 amplitude slope in major psychiatric disorders were discussed.

• 한국전자파학회논문지
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• 제16권6호
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• pp.549-555
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• 2005

본 논문은 전파 수집 및 감시 시스템 등에 사용되는 초고주파 신호의 도래 방향 측정에 관한 연구로써, 방향탐지 장치의 안테나를 통해서 수신된 신호들의 진폭차를 이용하여 신호의 입사 방향을 측정하는 진폭 비교 방향 탐지 방식과 동일한 안테나로 수신된 고주파 신호들의 위상차를 이용하여 전파의 도래 방향을 측정하는 위상 비교 방향 탐지 방식을 결합하는 새로운 기술이다. 본 방식은 위상 비교 기술의 정밀한 방향 탐지 능력과 진폭 비교 방식의 측정 방위 모호성 제거 능력을 복합하여 간단한 구성으로써 모호성이 없고 정밀하게 전파 도래 방향을 측정하는 기술이다. 제시된 방향 탐지 기술을 $360^{\circ}$ 전 방위각에서 전파의 방향을 측정하기 위해서 8개의 안테나를 원주를 따라서 $45^{\circ}$ 간격으로 일정 하게 배치하고, 인접한 안테나의 수신 신호 위상차를 이용하여 전파의 도래 방향을 측정하고, 진폭차를 이용하여 도래 방향 모호성을 제거하였을 때, 설계된 방향 탐지 장치의 모사 및 측정 결과는 도래 신호의 신호 대 잡음비가 30 dB인 경우에 $2.0\~6.0$ GHz주파수 범위에서 $0.5^{\circ}$ 이하의 양호한 방향 탐지 오차를 얻었다.

• 전자공학회논문지
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• 제50권3호
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• pp.139-145
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• 2013

본 논문에서는 스테레오 패닝 시스템에 대해 기존의 진폭 패닝이 가지는 문제점을 분석하였다. 이러한 문제점이 피드포워드 빗형 필터 형태로 발생하는 것을 관찰하고 이를 해결하기 위하여 피드백 빗형 필터를 사용한 스테레오 진폭 패닝 시스템을 제안하였다. 방향 인지에 대해 중요한 단서인 양이간레벨차의 차이가 최소가 되도록 하여 빗형 필터를 설계하였으며 제안된 시스템이 방향 인지에 관련된 대역에 대해 선택적으로 동작하도록 주파수 대역을 설정하였다. 제안된 시스템의 성능을 주관적 음질 평가를 통하여 검증하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제4권5호
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• pp.417-425
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• 2000

The underlying mechanism commonly applicable for both the positive and negative force-frequency relationships (FFR) was pursued in left atria (LA) of rat and rabbit. The species differences in the roles of $Na^+/Ca^{2+}$ exchanger and sarcoplasmic reticulum (SR), which are major intracellular $Ca^{2+}$ regulatory mechanisms in the heart, were examined in the amplitude accommodation to the frequency that changed from 3 Hz to the variable test frequencies for 5 minutes in the electrically field stimulated left atria (LA) of rat and rabbit. Norepinephrine strongly increased the frequency-related amplitude accommodation in both of rat and rabbit LA, while monensin, oubain or the reduced $Na^+$ and 0 mM $Ca^{2+}$ containing Tyrode solution increased the frequency-related amplitude accommodation only in the rabbit LA. Monenisn was also able to increase the frequency-related amplitude accommodation only in 1-day old rat LA but not in 4-week old rat LA that had 75% less $Na^+/Ca^{2+}$ exchanger with 97% higher SR than 1-day old rat LA. Taken together, it is concluded that the differences in the prevalence between myocardial $Na^+/Ca^{2+}$ exchanger and SR in the amplitude accommodation to the frequency-change determine the difference in the FFR between rat and rabbit heart.

• Journal of Information Processing Systems
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• 제13권4호
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• pp.677-688
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• 2017

In order to solve the undetected probability of multiple targets in ultra-wideband (UWB) through-the-wall radar imaging (TWRI), a time-delay and amplitude modified back projection (BP) algorithm is proposed. The refraction point is found by Fermat's principle in the presence of a wall, and the time-delay is correctly compensated. On this basis, transmission loss of the electromagnetic wave, the absorption loss of the refraction wave, and the diffusion loss of the spherical wave are analyzed in detail. Amplitude compensation is deduced and tested on a model with a single-layer wall. The simulating results by finite difference time domain (FDTD) show that it is effective in increasing the scattering intensity of the targets behind the wall. Compensation for the diffusion loss in the spherical wave also plays a main role. Additionally, the two-layer wall model is simulated. Then, the calculating time and the imaging quality are compared between a single-layer wall model and a two-layer wall model. The results illustrate the performance of the time-delay and amplitude-modified BP algorithm with multiple targets and multiple-layer walls of UWB TWRI.

• 산업기술연구
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• 제21권B호
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• pp.175-185
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• 2001

A numerical model is represented to calculate the reflected waves, the runup of waves and the wave induced velocities on impermeable slopes for the normally incident wave trains of nonlinear monochromatic wave and solitary wave. The finite amplitude shallow water equations with the effects of bottom friction are solved numerically in time domain using an explicit dissipative Lax-Wendroff finite difference method. The numerical model is verified by comparisons with the other numerical results, the measured data and asymptotic results. It is found that the uprushing and downrushing of incident waves may be accurately predicted by the present numerical model. Therefore, the present numerical model can be applicable to swells as well as long waves.

• 한국군사과학기술학회지
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• 제20권2호
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• pp.272-278
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• 2017

In this paper, we consider a single-channel amplitude comparison monopulse system(SCACMS). The monopulse ratio curve(MR-C) of the SCACMS can be controlled by an amplitude difference between sum and different signal, a phase difference and the coefficient of the signal processor. We first propose the SCACMS with multiple variables, and then apply a genetic algorithm to optimize the multiple variables in terms of minimizing a root mean square error. The simulation results show that when three variables of the SCACMS are jointly optimized, the linear region of the MR-C can be extended approximately 187 % compared to that of two variables.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.198-198
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• 2010

The low-k SiOCH thin films were prepared by CCP-PECVD method using BTMSM(Bis-trimethylsilylmethane) precursors deposited on p-Si wafer. The structural complexity originate the complex refractive constants of the films, and resulted the elliptical polarization of the incident linearly polarized light source of Xe-ramp in the range from 190nm to 2100nm. Phase difference and amplitude ratio between s wave and p wave propagating through SiOCH thin film was studied. After annealing, the amplitude of p wave was reduced more than s wave, and phase difference between p and s wave was also reduced.