• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06c
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• pp.125-128
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• 1994

선형예측기법으로 피치동기식 분석을 하기 위해 우선적으로 필요한 정보로서 유성음 신호의 영교차 구간별 평균 진폭변동율 추출에 의한 주기별 피치를 검출할 수 있는 기법을 제안하였다. 유성음의 제1포먼트 성분에 대한 각 영교차 구간에서의 평균진폭값은 성대 폐쇄시점에서 주기별 최대치를 나타내며, 평균진폭변동율은 "+" 영역의 평균진폭값과 선행하는 "-" 영역 값의 차로 표시한다. 이 평균 진폭 변동율은 성대파형의영향이 반영되어 주기성이 더욱 강조되므로 분석구간에 대한 구간별 평균피치와 변화의 정도를 이용하여 주기별피치정보를 추출할 수 있다. 검출결과는 구간별 평균피치와 비교하였으며, 좋은 결과가 나타나는 것을 확인할 수 있다.과가 나타나는 것을 확인할 수 있다.

• The Journal of the Acoustical Society of Korea
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• v.34 no.3
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• pp.227-233
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• 2015

In this paper, we propose music and voice separation using kernel sptectrogram models backfitting based on log-spectral amplitude estimator. The existing method separates sources based on the estimate of a desired objects by training MSE (Mean Square Error) designed Winer filter. We introduce rather clear music and voice signals with application of log-spectral amplitude estimator, instead of adaptation of MSE which has been treated as an existing method. Experimental results reveal that the proposed method shows higher performance than the existing methods.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.42-49
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• 2021

As a measure of susceptibility on the combustion instability, thermo-acoustic instabilities in rocket combustion system was considered for the estimation of the operational stability margin. Growth rate, which governs the asymptotic stability behavior of the system, was determined from the dynamic data measured during combustion tests in order to understand the dynamic characteristics of combustor system. Frequency transform technique was first applied to determine the system parameters such as growth rate and/or damping coefficient for an interested mode from the time series pressure data, and the PDFs of pressure amplitude were extracted from the amplitude envelope of pressure oscillation for the stochastic analysis.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.5
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• pp.529-536
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• 2019

In this paper, the signals of the sensor for extracting characteristic parameters of the rotor are collected and the performance of the extraction technique is analyzed. To this end, a vibration test league was developed for conducting model tests to analyze the signal characteristics under normal operation. As a result, it is judged that no change in the measured the raw data amplitude will occur in the acceleration sensor with the unbalanced mass measured from the acceleration sensor. Performing FFT showed a significant increase in amplitude of the rotational frequency of 20 Hz as the unbalanced mass increased. The analysis results according to the change in the unequal mass of the speed sensor also showed a significant increase in the 1X Harmonics component, such as the acceleration sensor. There was no change in the amplitude of the acceleration sensor data when the misalignment occurred, and for the Envelope data, the amplitude of 2X (40 Hz) was increased depending on the degree of misalignment. The velocity sensor at change of misalignment also showed similar results to the acceleration sensor, and the peak was reduced at 600 Hz as the load increased in the frequency spectrum.

• The Journal of the Acoustical Society of Korea
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• v.9 no.6
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• pp.15-21
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• 1990

유-무-묵음 분류 과정은 음성분석시에 아주 중요한 문제중의 하나이다. 음성에너지, ZCR, 자기 상관계수, LPC 계수, 예측에러 에너지등을 퍼래미터로 사용하여 지금까지 많은 분류기법이 제안되어져 왔다. 이런기법들은 기본적으로 퍼래미터를 추출해야 하고, 이 때문에 많은 계산량이 요구되고, 이들 퍼 래미터는 음성 본래의 정보들의 대부분을 상실하게 된다. 이 때문에 각 프레임의 진폭분포를 사용하는 새로운 앨고리즘을 제안하였다. 첫째로 V-U-S 영역은 개별 진폭분포형태를 가지기 때문에 주어진 프레 임에서 진폭분포를 구한다. 그런 다음에는 신경망을 통해 분류를 하게 된다. 신경망은 문덕값을 별도로 선정할 필요없고, 배경잡음에 강력하며, 또한 실시간 처리에 적합하다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.2
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• pp.17-24
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• 2023

A post-processing technique for the measurement signal of a solenoid-type sensor is introduced. The solenoid-type sensor nondestructively evaluates an external tendon of prestressed concrete using the total flux leakage (TFL) method. The TFL solenoid sensor consists of primary and secondary coils. AC electricity, with the shape of a sinusoidal function, is input in the primary coil. The signal proportional to the differential of the input is induced in the secondary coil. Because the amplitude of the induced signal is proportional to the cross-sectional area of the tendon, sectional loss of the tendon caused by ruptures or corrosion can be identified by the induced signal. Therefore, it is important to extract amplitude information from the measurement signal of the TFL sensor. Previously, the amplitude was extracted using local maxima, which is the simplest way to obtain amplitude information. However, because the sampling rate is dramatically decreased by amplitude extraction using the local maxima, the previous method places many restrictions on the direction of TFL sensor development, such as applying additional signal processing and/or artificial intelligence. Meanwhile, the proposed method uses amplitude demodulation to obtain the signal amplitude from the TFL sensor, and the sampling rate of the amplitude information is same to the raw TFL sensor data. The proposed method using amplitude demodulation provides ample freedom for development by eliminating restrictions on the first coil input frequency of the TFL sensor and the speed of applying the sensor to external tension. It also maintains a high measurement sampling rate, providing advantages for utilizing additional signal processing or artificial intelligence. The proposed method was validated through experiments, and the advantages were verified through comparison with the previous method. For example, in this study the amplitudes extracted by amplitude demodulation provided a sampling rate 100 times greater than those of the previous method. There may be differences depending on the given situation and specific equipment settings; however, in most cases, extracting amplitude information using amplitude demodulation yields more satisfactory results than previous methods.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1867-1872
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• 2016

In the area of digital signal processing, it is necessary to improve the quality of the speech signal after removing the background noise which exists in a various real environments. The important thing to consider when removing the background noise acoustically is that to solve the problem, depending on the information of the human auditory mechanism is mainly the amplitude spectrum of the speech signal. This paper introduces the characteristics of a frequency-weighted spectrum shaping filter for the extraction of the amplitude spectrum of the speech signal with the primary purpose. Therefore, this paper proposes an algorithm using the methods of a Wiener filter and the frequency-weighted spectrum shaping filter according to the acoustic model, after extracted the amplitude spectral information in the noisy speech signal. The spectral distortion (SD) output of the proposed algorithm is experimentally improved more than 5.28 dB compared to a conventional method.

• Korean Journal of Optics and Photonics
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• v.14 no.2
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• pp.155-160
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• 2003

We have constructed and characterized a depolarized fiber-optic gyroscope that uses a length of single-mode fiber as a sensing loop fiber. We have also calculated the noise characteristics of the gyroscope and have found an optimum phase modulation depth that gives the highest signal-to-noise ratio in the gyroscope. The random walk coefficient as small as 0.7$\times$10$^{-3}$ deg/√hr was obtained at the modulation depth of around 2.4 rad. The random walk coefficients measured at various modulation depths were found to be in reasonable agreement with the calculation.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.474-479
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• 2018

In this study, ultrasound-assisted extraction conditions of total anthocyanins and total phenolic compounds from Campbell early grape (Vitis labruscana) were optimized via response surface methodology using a Box-Behnken design. Three independent variables, including solid-liquid ratio (1/30-1/50 g/mL), extraction time (2-10 min), and amplitude (20-100%), significantly affected total anthocyanin content. However, no significant effect of these variables was observed in the total phenolic compound content. The optimized extraction conditions were solid-liquid ratio of 1/48.13 g/mL, extraction time of 2 min, and amplitude of 20%. Under these conditions, the predicted values of total anthocyanins and total phenolic compounds were 94.96 and 1,661.16 mg/100 g dry weight (DW), respectively. The experimental values of total anthocyanins and total phenolic compounds were 88.25 and 1,554.37 mg/100 g DW, respectively, which is well matched with the predicted values within 7.5% difference.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.147-150
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• 1995

최근의 마취과학에 관한 연구에 있어서의 주된 경향은 마취심도 및 의식수준의 결정을 신경생리학적인 관점에서 분석하고자 하는 것이다. 즉, 마취와 의식에 관한 인간의 뇌가 가지고 있는 기능이나 약리학적인 반응을 대표할 수 있는 생체신호를 검출, 분석하여 정량화하고 이들을 이용하면 마취심도 및 의식수준과의 큰 상관관계를 얻을 수 있을 것이라 가정하는 것이다. 본 연구에서는 청각유발전위 (LAEP, Long latency Auditory Evoked Potential)를 검출하여 추출된 변수들과 마취제 투여량간의 변화에 따른 상관성을 분석하고자 하였다. 수술환자(17명)를 대상으로 실험을 실시하였으며 마취제로서는 Midazolam과 Diazepam을 인체로 투여하고 1 KHz와 2 KHz의 청각자극을 제시하였을 때 피검자로부터 발생되는 LAEP를 검출하였다. 검출된 LAEP로부터 추출된 N100과 P300의 진폭은 마취량의 증가에 따라서 간소함을 알 수 있었으며, 이러한 유의한 상관성을 보이는 진폭의 변화는 마취제의 투여에 따른 의식수준의 변화를 나타내는 지수(index)의 설정 및 알고리듬의 수립에 이용될 수 있을 것이다.