• 한국안전학회지
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• 제18권1호
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• pp.38-43
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• 2003

In this paper, the low cycle fatigue(LCF) life tests were carried out under waveforms of asymmetric triangle($4{\times}10^{-3}$ and $4{\times}10^{-10}$ strain rate) and hold-time(1min and 10min) in strain control. In triangular waveform, the fatigue lives of fast-slow waveforms were decreased to about 63-73% and them of slow-fast waveforms were down to about 23-24% compared to them of fast-fast waveforms. The shapes of fracture surfaces were transgranular in fast-fast and fast-slow waveforms and intergranular in slow-fast ones. The fatigue lives of slow-fast waveforms were remarkedly shorter than them of hold-time waveforms even though cycle times of hold time waveforms were longer than them of slow-fast ones. The damage mechanisms of frature surfaces were mixed frature with both transgranular and intergranular, but intergranular fratures were r-type cavity in hold-time waveforms and w-type cavity in slow-fast ones.

• Korean Journal of Acupuncture
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• 제26권4호
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• pp.13-22
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• 2009

Objectives : Informations on pulse diagnosis in literature are based on diagnosing pulse waveforms on supine posture. However, today's pulse waveforms are measured on various postures for the convenience of patients or doctors. For objective measurement, the effect of posture on the pulse waveforms should be considered. The objective of this study was to find posture-related changes in the radial pulse waveforms. Methods : We used an instrument, DMP-3000(DAEYOMEDI Co., Ansan, Korea), measuring radial pulse waveforms noninvasively by tonometric method. 25 male subjects participated in the trial. Before measuring radial pulse waveforms subjects had rest for 5 min. The pulse waveforms were measured on the left wrist. Each subject underwent this course on the supine, sitting, and standing posture. We analyzed pulse waveforms with Height-parameters, Time-parameters, Energy, and Elastic rate. Results : Height-parameters(h1~h5) on the supine posture were bigger than those on the sitting and standing posture. In case of Time-parameters, the parameters making up systolic time decrease in order of on standing, sitting, and supine position. However, systolic time and diastolic time didn't have any changes. Energy of pulse was the biggest on supine posture and Elastic rate on standing posture. Conclusions : In this study we found that posture changes affect radial pulse waveforms. For quantification of the changes, more trials should be done. After analyzing much data we might apply parameters of pulse waveforms changed by posture. Also, we might diagnose special disease with properties of pulse waveforms by posture.

• 조명전기설비학회논문지
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• 제18권4호
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• pp.160-164
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• 2004

본 논문에서는 근사화된 해석파형을 사용한 DS/CDMA 시스템에 적용하였다. 제안된 칩 파형은 균일 엔벌로프를 가진 균일칩 파형과 비균일 엔벌로프를 가진 비균일칩 파형의 두 가지로 형태로 분류한다. 근사화된 해석칩 파형의 단순성은 칩파형, 엔벨로프, 위상, 상관관계와 대역폭 성질 등을 비교하고 증명하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1543-1546
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• 2008

Modified pulse waveforms were applied to an AC plasma display panel with an auxiliary electrode in order to improve the operation voltage margin. Reciprocal sustain pulse waveforms and modified auxiliary pulse waveforms were applied to the sustain and auxiliary electrode, respectively. During the sustain period, the influence of the address electrode on the luminous efficacy of long-coplanar gap discharges was mitigated by application of reciprocal sustain pulse waveforms. Modified auxiliary pulse waveforms maintained the high efficacy obtained from the AC PDP with an auxiliary electrode. The proposed reciprocal sustain and modified auxiliary pulses waveforms can induce stable discharges in long-coplanar gap discharges and can control wall charges with a wider auxiliary pulse voltage margin, thereby enhancing the luminous efficacy of the AC PDP with an auxiliary electrode.

• 대한음성언어의학회:학술대회논문집
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• 대한음성언어의학회 1995년도 제4회 학술대회 심포지움 및 워크샵
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• pp.141-153
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• 1995

CSpeech is a software package that implements an audio waveform/speech analysis workstation on an IBM Personal Computer or hardware compatible computer. Features include digitizing audio waveforms on single or multiple channels, displaying the digitized waveforms, playing back audio waveforms from selected intervals of sing1e channels, saving and retrieving waveforms from binary format disk files, and analysing audio waveforms for their temporal and spectral properties. The distinguishing characteristics of CSpeech are its support for multiple channels, minimal restrictions on sample rate and waveform duration support fur a variety of hardware configurations, fast graphics display, and its user- extensible menu- based command structure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.553-555
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• 1996

This paper concerns with a method to improve the current and power waveforms of the variable speed $3{\Phi}$ AC motor system driven by the single-pulse PWM, and the current waveforms and $3{\Phi}$ power waveforms are analyzed by FFT under various running conditions. By the performance analysis through the experiments, the following results have been obtained. AC source of pseudo sine waveform can be obtained from the modulated alternating square voltage by means of the well designed LC filter. It is confirmed that current waveforms and $3{\Phi}$ power waveforms can be improved by utilizing the high order low pass LC filter than that of lower order. Especially, current waveforms and $3{\Phi}$ power waveforms tan be much improved at low frequency domain. $3{\Phi}$ power waveforms have a smatter ripple and bigger power by utilizing the high order low pass LC filter than that of lower order. Also, the running condition of $3{\Phi}$ AC motor is good at low frequency domain.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.55-64
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• 2016

The development of high-speed rail (HSR) has had a major impact on the power supply grid. Based on the monitored waveforms of HSR, a pattern recognition approach is proposed for the first time in this paper to identify the operating conditions. To reduce the data dimensions for monitored waveforms, the principal component analysis (PCA) algorithm was used to extract the characteristics and their waveforms from the monitored waveforms data. The dynamic time wrapping (DTW) algorithm was then used to identify the operating conditions of the HSR. Cases studies show that the proposed approach is effective and feasible, and that it is possible to identify the real-time operating conditions based on the monitored waveforms.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1824-1826
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• 1997

In this paper, in order to obtain statistical informations on lightning electromagnetic waveforms, electric field waveforms produced by lightning return strokes were measured and analyzed. The electric field measuring system consists of hemisphere antenna 30[cm] in diameter, integrator and data acquisition. system. The frequency bandwidth of the measuring system is 200[Hz] to 1.56[MHz], and the sensitivity is 0.96[mV/V/m]. The mean value of front time of electric field waveforms produced by positive lightning return strokes is 5.87[${\mu}s$], and that of negative is 4.12[${\mu}s$]. The mean values of zero-crossing time for positive or negative electric field waveforms are 35.00 and 26.61[${\mu}s$], respectively. The mean value of percentage dip-depth for positive electric field waveforms is 33.68[%], and that for negative is 28.36[%].

• 한국전기전자재료학회논문지
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• 제32권2호
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• pp.151-156
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• 2019

The aim of this investigation is to detect specific waveforms in a distribution line prior to the occurrence of a fault. Conditions were introduced such that a feeder remote terminal unit (FRTU) of the distribution automation system selects and stores fault waveforms from the different waveforms detected in the distribution line. In addition, an algorithm was developed to detect specific waveforms from the fault waveforms stored using the FRTU. This algorithm exploits the duration and periodicity of harmonic changes in voltage and current. The efficacy of the algorithm was confirmed based on the measurements of fault waveforms in an actual distribution line. The results indicated that faults in a distribution line can be predicted via experimental measurements.

• 조명전기설비학회논문지
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• 제16권2호
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• pp.113-120
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• 2002

본 논문은 인체에 의해 발생하는 정전기 방전과도전압 파형의 특성에 관한 것으로 정전기 방전전압의 피크 크기와 초기상승부분의 특성에 대한 통계를 분석하기 위해서 여러 가지 실험조건에서 정전기 방전전압을 측정하였다. 정전기 방전전압의 측정에는 주파수대역이 DC∼400[MHz]인 전압측정계를 사용하였으며, 정전기 방전전압의 파형은 전류 파형과 거의 동일하였다. 또한 본 연구에서 제안한 등가회로를 적용한 시뮬레이션결과는 측정결과와 거의 일치하였다. 정전기 방전전압 파형은 접촉 물체의 재질과 접근속도에 크게 영향을 받으며, 빠른 접근일 때가 느린 접근일 때보다 초기상승시간이 짧은 파형으로 나타났다. 손에 의한 정전기 방전전압의 상승시간은 10∼30[ns]로 비교적 길었으나, 크기는 작았다. 반면에 절연손잡이를 갖는 드라이버를 통한 정전기 방전전압 파형은 1[ns]이하의 매우 짧은 상승시간과 매우 큰 피크값을 나타내었다. 본 연구결과는 저전압 소전류인 전자기기의 정전기 장해에 대한 대책의 마련에 응용될 것이다.