• 대한후두음성언어의학회지
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• 제30권1호
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• pp.28-33
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• 2019

Background and Objectives : Laryngeal electromyography (LEMG) is valuable to evaluate the innervation status of the laryngeal muscles and the prognosis of vocal fold paralysis (VFP). However, there is a lack of agreement on quantitative interpretation of LEMG. The aim of this study is to measure the motor unit action potentials (MUAP) quantitatively in order to find cut-off values of amplitude, duration, phase for unilateral vocal fold paralysis patients. Materials and Method : Retrospective chart review was performed for the unilateral VFP patients who underwent LEMG from March 2016 to May 2018. Patient's demography, cause of VFP, vocal cord mobility, and LEMG finding were analyzed. The difference between normal and paralyzed vocal folds and cut-off values of duration, amplitude, and phase in MUAP were evaluated. Results : Thirty-six patients were enrolled in this study. Paralyzed vocal fold had significantly longer duration (p=0.021), lower amplitude (p=0.000), and smaller phase (p=0.012) than the normal. The cut-off values of duration, amplitude, and phase in MUAP for unilateral VFP were 5.15 ms, $68.35{\mu}V$, and 1.85 respectively. Conclusion : An analysis of MUAP successfully provided quantitative differences between normal and paralyzed vocal folds. But, additional research is needed to get more available cut-off value which is helpful to evaluate the status of laryngeal innervations.

• 조명전기설비학회논문지
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• 제26권11호
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• pp.87-96
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• 2012

This paper propose a development of surface permanent mount synchronous generator(SPMSG) for 5-phase 5Kw in order to study a polyphase ac machinery that keep hold of advantages more than traditional three-phase squirrel-cage induction motor, such as reducing a amplitude of torque pulsation decreasing electric noises, and increasing the reliability. Design methods of the generator use a development tools with Maxwell 2D and Simplorer. There are designed drawing of manufactured frames of the SPMSG. A amplitude and waveform of the generated electromotive force, FFT analysis of harmonics within output voltages, and reviewing a experiment results are shown by variable output frequency. We are presenting a design and manufacture methods for the SPMSG.

• 센서학회지
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• 제14권1호
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• pp.42-46
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• 2005

It has been known that 1/f noise of MOSFET is generated by superposition of random telelgraph signals (RTS). In this study, jitters and phase noise caused by 1/f noise of MOSFET are analysed with RTS supplied to all of the nodes of the CMOS ring oscillator under investigation. Through the analysis of jitters and jitter ratios with varying values of the amplitude of RTS, it is found that the jitters and the jitter ratios are proportional to the amplitude of RTS. And the analysis of FFT of the output of the ring oscillator reveals that the jitters are closely related to the phase noise of the high order harmonics of the ring oscillator outputs.

• 열처리공학회지
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• 제24권3호
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• pp.144-148
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• 2011

Change in damping capacity with strain amplitude was studied in Mg-Al-Si alloy in as-cast, solution-treated and aged states, respectively. The as-cast microstructure of the alloy is characterized by eutectic ${\beta}$($Mg_{17}Al_{12}$) phase and Chinese script type $Mg_2Si$ particles. The solution treatment dissolved the ${\beta}$ phase into the matrix, while the aging treatment resulted in the distribution of continuous and discontinuous type ${\beta}$ precipitates. The solution-treated microstructure showed better damping capacity than as-cast and aged microstructures both in strain-dependent and strain-independent damping regions. The decrease in second-phase particles which weakens the strong pinning points on dislocations and distribution of solute atoms in the matrix, would be responsible for the enhanced damping capacity after solution treatment.

• 천문학회보
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• 제37권2호
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• pp.125.1-125.1
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• 2012

The wave number 4 (wave-4) and wave number 3 (wave-3) longitudinal structures in the thermospheric neutral mass density are understood as tidal structures driven by diurnal eastward-propagating zonal wave number 3 (DE3) and wave number 2 (DE2) tides, respectively. However, those structures have been identified using data from limited time periods, and the consistency and recurrence of those structures have not yet been examined using long-term observation data. We examine the persistence of those structures by analyzing the neutral mass density data for the years 2001-2008 taken by the CHAllenging Minisatellite Payload (CHAMP) satellite. During years of low solar activity, the amplitude of the wave-4 structure is pronounced during August and September, and the wave-4 phase shows a consistent eastward phase progression of $90^{\circ}$ within 24 h local time in different months and years. During years of high solar activity, the wave-4 amplitude is small and does not show a distinctive annual pattern, but the tendency of the eastward phase shift at a rate of $90^{\circ}$/24 h exists. Thus the DE3 signature in the wave-4 structure is considered as a persistent feature. The wave-3 structure is a weak feature in most months and years. The amplitude and phase of the wave-3 structure do not show a notable solar cycle dependence. Among the contributing tidal modes to the wave-3 structure, the DE2 amplitude is most pronounced. This result may suggest that the DE2 signature, although it is a weak signature, is a perceivable persistent feature in the thermosphere.

• 한국전자파학회논문지
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• 제27권6호
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• pp.577-580
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• 2016

모노펄스 레이더에 대한 효과적인 재밍은 전파를 왜곡시키는 것이다. 그 중 대표적인 전파왜곡 기법은 두 개의 송신기를 이용하는 크로스 아이 기법이다. 크로스 아이 기법은 모노펄스 레이더의 구현 구조에 관계없이 각도를 기만할 수 있지만, 충분한 각도기만 효과를 갖기 위해서는 두 송신기의 위상 및 진폭 정확도가 확보되어야 한다. 이러한 위상 및 진폭 정확도는 전파왜곡 시스템을 구현하는데 있어서 핵심적인 요구 성능 파라미터이고, 목표로 하는 각도 오차에 따라 그 요구값이 달라진다. 본 논문에서는 목표하는 각도 오차에 따라 필요한 최소 위상차 및 진폭비를 수식으로 유도하고 그 결과를 분석한다.

• 한국전자파학회논문지
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• 제18권2호
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• pp.219-226
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• 2007

본 논문에서는 DPSK(Quadrature Phase Shift Keying), MQAM(M-ary quadrature Amplitude Modulation), OFDM(Orthogonal Frequency Division Multiplex)-MQAM, OFDM-DPSK 변조 방식에 대한 SER(Symbol Error Rate)을 위상 잡음에 대한 영향을 정량적으로 도출하였다. 시뮬레이션(MATLAB)을 이용하여 위상 잡음이 없는 이상적인 경우와 비교하였으며, 또한 상기 변조 방식에 대하여 심벌 레이트와 변조 대역폭간의 비에 따른 위상 잡음 영향을 분석하였고, 각 변조에서 요구되는 최소 위상 잡음 조건을 제시하고 도출하였다.

• 한국통신학회논문지
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• 제35권2C호
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• pp.203-209
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• 2010

본 논문에서는 크기 및 위상 변이 선택사상 기법(amplitude and phase variant SLM)을 제안한다. 이 기법은 직교 진폭 변조(quadrature amplitude modulation; QAM)로 변조된 직교 주파수 분할 다중화(orthogonal frequency division multiplexing; OFDM)신호에서 최대전력 대 평균전력의 비(peak to average power ratio; PAPR)를 감소시킨다. 주파수 영역에서 QAM 심볼들의 위상만을 회전시키는 기존의 SLM과 비교하였을 때에 제안된 기법은 QAM 심볼들로 대응되기 전의 이진 데이터의 특정 위치에 이진 시퀀스를 곱해줌으로써 QAM 심볼에 대응 시에 위상은 물론 크기까지 변화시켜준다. 모의실험 결과는 제안된 기법이 QAM 변조된 OFDM 신호들에 대하여 기존의 SLM 보다 PAPR 감소 성능이 더 좋다는 것을 보여준다.

• 정보저장시스템학회논문집
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• 제1권2호
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• pp.143-149
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• 2005

In this paper we propose a novel volume hologram encryption system with binary amplitude masks rather than phase masks, in which volume holograms can be securely recorded against the attacks by a third party. In our system, the encryption is done by multiplexing two volume holograms in such a way that an original binary data page is first stored as a volume hologram by interference with a binary amplitude mask and then the complementary data page is stored as another volume hologram by interference with the complementary binary amplitude mask over the first hologram. The operation principle of our system is explained with the well-known theory of recording and reading a volume hologram in a photorefractive material and the experimental results are presented. Experimental data show that our encryption system is protected from blind decryptions by randomly-generated incorrect amplitude masks.

• 한국전자파학회논문지
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• 제21권4호
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• pp.433-442
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• 2010

본 논문에서는 멀티베이스라인 인터페로미터 방향 탐지 시스템에서 진폭 및 위상 부정합 오차를 보정할 수 있는 공분산행렬 기반 자체 교정 알고리즘을 제안한다. 제안된 기법은 비용함수를 정의한 후 제한 조건을 갖는 비선형 최소화 방법으로서, 공간 섹터를 이용하여 부정합 오차를 획기적으로 교정하는 알고리즘이다. 다만 공간 섹터를 선정하기 위하여 초기 추정각을 요구하는 단점이 있으나, 이는 일반적인 비선형 최소화 문제의 공통적인 단점이다. 적절한 공간 섹터 간격을 선정하여 시뮬레이션한 결과, 제안된 방법이 기존 인터페로미터 방식보다 표본바이어스, 표본표준편차, 평균제곱오차면에서 획기적으로 우수한 통계적 성능을 보여주었다. 더구나 섹터 간격이 도래각과 $5^{\circ}$ 이내일 경우에, 30 dB의 진폭 부정합 및 $50^{\circ}$ 이상 큰 값의 위상 부정합이 발생하는 경우에도 획기적인 보정 능력을 보여주었으며, 신호대 잡음비에도 덜 민감한 특징을 나타내었다.