• 대한한방내과학회지
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• 제30권1호
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• pp.173-180
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• 2009

Objectives : The aim of this study was to investigate the evaluation of gastrointestinal parasympathetic nerve activity by comparing between HRV and bowel sound parameters in patients with functional dyspepsia. Methods : 62 patients (male 22, female 40) were enrolled. HRV was measured in all patients. and TP (total power), LF (low frequency density: 0.04$\sim$0.15Hz), HF (high frequency density: 0.15$\sim$0.4Hz). and LF/HF ratio were analyzed. HF band is a reflection of parasympathetic activity. and the LF-to-HF ratio is considered a marker of sympathovagal balance. Bowel sounds were recorded at the day after, and postprandial %BS was used to indicate the gastric vagal activity after eating. HRV and bowel sound parameters were compared. and correlation between them was analyzed. Results : There was no difference in LF/HF ratio between patient group and healthy group of other report. According to values of %BS, each patient was classified into a normal (>6 %BS) or hypoactivity (<6 %BS) of gastric vagus nerve group. HF component of the hypoactivity group was not significantly higher than that of the normal group. There was no correlation between HRV and bowel sound parameters. Conclusions : Because no correlation was found between HRV and bowel sound parameters in patients with functional dyspepsia, we concluded that it is not proper to evaluate gastric vagus nerve activity by HRV measurement.

• 한국음향학회지
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• 제19권3호
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• pp.86-91
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• 2000

본 논문에서는 피아노 음을 FFT(Fast Fourier Transform)를 이용하여 주파수 영역으로 변환한 후, 크기(magnitude)와 위상(phase)에 대한 특성들을 분석한다. 이 분석한 결과로 크기와 위상을 모델링하여 파라미터를 생성한다. 크기의 특성에서 기본주파수와 고조파 부분은 다른 부분에 비해 크기가 매우 크다. 그래서 이 부분의 모델링은 오차를 줄이기 위해 곡선의 적합성(Curve Fitting) 방법을 이용하였고, 노이즈 부분의 모델링은 기본주파수 전후의 노이즈가 피아노 음색 특성에 중요한 역할을 하고 불규칙하므로 선분 근사법을 이용하였으며, 크기가 작고 완만하게 변하는 나머지 노이즈 부분은 곡선의 적합성을 이용하였다. 위상은 크기에 적응한 방법과 동일하게 적용하였다. 생성된 파라미터로 크기와 위상을 만들어 역변환 FFT를 하면 피아노 원음에 매우 근접한 음을 얻을 수 있다.

• 한국음향학회지
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• 제25권3호
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• pp.129-136
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• 2006

소음에 대한 인간의 심리적 인지는 소음의 여러 가지 물리적 요인에 의하여 영향을 받는다. 그러나 현재의 환경소음 평가는 A 가중치 등가 소음 수준을 기준으로 평가되고 있으며 인간의 다양한 감성적 요인을 반영하지 못하고 있다. 따라서 본 연구에서는 환경소음 평가를 위하여 환경소음원 43개에 대하여 주관평가와 통계적 분석방법을 사용하여 인간의 감성에 영향을 주는 음질인자 (Sound quality factor)를 분석하였다. 분석방법은 먼저 다양한 환경소음원에 대한 음질물리량 (Sound quality metrics)을 분석하여 음원을 분류하였으며 분류된 음원의 주된 음질 물리량을 고찰하였다. 그리고 쌍대비교법 (Paired comparisons method)과 어의분별척도법 (Semantic differential method)을 사용하여 주관 평가를 실시하고 음질의 요인을 분석하였으며 물리량과의 관계를 규명하였다. 마지막으로 요인에 대한 물리량의 기여도를 분석함으로써 환경소음의 감성적 인지에 대한 기초 물리량을 설정하였다.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.43-49
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• 2006

In this paper, an index for the evaluation of a vehicle intake booming noise and intake sound quality were developed through a correlation analysis and a multiple factor regression analysis of objective measurement and subjective evaluation data. At first, an intake orifice noise was measured at the wide-open throttle test condition. And then, an acoustic transfer function between intake orifice noise and interior noise at the steady state condition was estimated. Simultaneously, subjective evaluation was carried out with a 10-scale score by 8 intake noise and vibration expert evaluators. Next, the correlation analysis between the psychoacoustic parameters derived from the measured data and the subjective evaluation was performed. The most critical factor was determined and the corresponding index for intake booming noise and sound quality are obtained from the multiple factor regression method. And, the optimal design of intake system was studied using the booming noise and the sound quality evaluation index for expectation performance of intake system. Conclusively, the optimal designing parameters of intake system from noise level and sound quality whose point of view were extracted by adapting comparative weighting between the booming noise and sound quality evaluation index, which optimized the process. These work could be represented guideline to system engineers, designers and test engineers about optimization procedure of system performance by considering both of noise level and sound quality.

• 전자공학회논문지B
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• 제32B권7호
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• pp.1025-1035
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• 1995

In this paper, we realize a real time digital FM synthesizer based on genetic algorithm using a general purpose digital signal processor. Especially, we synthesize diverse music sounds nicely using a synthesis model consisting of a single modulator and multiple carriers. Also we present genetic algorithm-based technique which determines optimal parameters for reconstruction through FM synthesis of a sound after analyzing the spectrum of PCM data as a standard music sound using FFT. Using the suggested parameter extractiuon algorithm, we extract parameters of several instruments and then synthesize digital FM sounds. To verify the validity of the parameter extraction algorithm as well as realization of a real time digital music synthesizer, the evaluation is first done by listening the sound directly as subjective test. Secondly, to evaluate the synthesized sound objectively with an engineering sense, we compare the synthesized sound with an original one in a time domain and a frequency domain.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.530-533
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• 2005

Recently, modern reciprocating air compressors tend to be smaller and lighter. But, as the development of performance, they have many problems for noise and vibration. For this reason, many researches are processing for the reduction of noise and vibration by arranging cylinders with V/W type. Especially, noise and vibration problems of reciprocating air compressor cause a rotating unbalance of crankshaft, so it needs a change of crankshaft parameters appropriately. Hence in this study, we changed crankshaft parameters to solve the rotating unbalance and compared results in order to verify the noise and vibration reduction between new and original air compressor. According to modify a crankshaft parameter, the improvements of noise and vibration were showed results of spectrum measured at selected points of the air compressor crankshaft housing and sound intensity contours measured at a belt left side, table that figure out characteristics of noise. Furthermore, we analyzed objective sound quality metrics with recording data of systems. The results showed that, the new design has improved the level of the first harmonic of vibration displacement, noise and objective sound quality metrics.

• Fibers and Polymers
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• 제7권4호
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• pp.450-456
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• 2006

The objectives of this study were to investigate physiological and psychological responses to the rustling sound of Korean traditional silk fabrics and to figure out objective measurements such as sound parameters and mechanical properties determining the human responses. Five different traditional silk fabrics were selected by cluster analysis and their sound characteristics were observed in terms of FFT spectra and some calculated sound parameters including level pressure of total sound (LPT), Zwicker's psychoacoustic parameters - loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z), and sound color factors such as ${\Delta}L\;and\;{\Delta}f$. As physiological signals, the ratio of low frequency to high frequency (LF/HF) from the power spectrum of heart rate variability, pulse volume (PV), heart rate (HR), and skin conductance level (SCL) evoked by the fabric sounds were measured from thirty participants. Also, seven aspects of psychological state including softness, loudness, sharpness, roughness, clearness, highness, and pleasantness were evaluated when each sound was presented. The traditional silk fabric sounds were likely to be felt as soft and pleasant rather than clear and high, which seemed to evoke less change of both LF/HF and SCL indicating a negative sensation than other fabrics previously reported. As fluctuation strength(Z) were higher and bending rigidity (B) values lower, the fabrics tended to be perceived as sounding softer, which resulted in increase of PV changes. The higher LPT was concerned with higher rating for subjective loudness so that HR was more increased. Also, compression linearity (LC) affected subjective pleasantness positively, which caused less changes of HR. Therefore, we concluded that such objective measurements as LPT, fluctuation strength(Z), bending rigidity (B), and compression linearity (LC) were significant factors affecting physiological and psychological responses to the sounds of Korean traditional silk fabrics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.141-146
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• 2007

A gear whine sound due to the axle system is one of the most important sound qualities in a sport utility vehicle (SUV). In the previous research about the gear whine sound, it was known that it is difficult to evaluate the gear whine sound objectively by using the only A-weighted sound pressure level because of the masking effect. In this paper, for the objective evaluation of the axle-gear whine sound, the characteristics of the axle-gear whine sound is at the first investigated based on the synthetic sound technology and the new objective evaluation method for the axle-gear whine sound is developed by using the sound metrics, which is the psychoacoustics parameters, and the artificial neural network (ANN) used for the modeling of the correlation between objective evaluation and subjective evaluation.

• 한국음향학회지
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• 제36권1호
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• pp.78-87
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• 2017

본 논문에서는 심리음향학적 연구 방법론을 음악의 작품 분석에 적용하여 음악의 매개체인 소리에 내재된 주관성을 객관화하고자 한다. 먼저, 대표적인 표제음악인 베를리오즈의 '환상교향곡'에서 18개의 샘플음원을 추출한 다음 쯔비커의 음질 파라메터(Loudness, Sharpness, Roughness, Fluctuation Strength)를 이용해서 샘플음원의 객관적 음질을 평가하였다. 주관적 음질 평가를 위하여 환상교향곡의 표제성을 기초로 9개의 대표 음질형용사를 추출한 다음 수치등급평가법과 쌍대비교법을 사용하여 1차 청음평가를 수행하였다. 1차 청음평가결과의 요인분석법을 통하여 "밝은", "시끄러운", "현실적인"의 세 가지 음질을 추출하였다. 세 가지 음질 형용사를 사용하여 2차 청음평가를 수행하고 그 결과를 객관적 음질 파라메터와 상관분석을 수행하여 음질지표를 개발하였다.

• 대한한방내과학회지
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• 제28권4호
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• pp.769-778
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• 2007

Background & Object : Postprandial epigastric fullness is one of common symptoms in functional dyspepsia, but its pathophysiological mechanism has still been unknown. In this study, its association between postprandial epigastric fullness and pyloric valve disturbance was studied through analysis of bowel sounds and electrogastrography. Methods : Bowel sounds and electrogastrography were recorded together for fasting 15 min and postprandial 40 min. Parameters of bowel soundincluding motility index, sound to sound interval, standard deviation of sound to sound interval, sounds per minute, % of bowel sound, sound length, intensity, dominant frequency of sounds, and postprandial / fasting ratio of dominant frequency of sounds were analyzed with a specialized program. By electrogastrography, regularity of slow waves and power ratio were obtained. Results : Significances of bowel sounds appeared in motility index (p=0.046), dominant frequency of fasting (p=0.048), postprandial (p=0.003), and the ratio of postprandial/fasting (p=0.000); those of EGG parameters were shown in postprandial regularity of slow waves (p=0.006) and power ratio (p=0.011). Conclusion : Pyloric valve disturbance was a cause of postprandial epigastric fullness in patients with functional dyspepsia. Analysis of bowel sound might be useful in diagnosing its existence.