• 한국컴퓨터정보학회논문지
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• 제19권6호
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• pp.93-100
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• 2014

본 연구의 목적은170dB 이상의 고충격 소음원에서 실내 충격소음을 측정 평가 할 수 있는 측정시스템 구축 방법을 제안하는데 있다. 이러한 목적을 달성하기 위하여 실내충격소음 측정시스템용 시험장을 설계 및 구현하고, 충격소음 측정용 마이크로폰, Head & Torso Simulator, Ear Simulator를 구성하였다. 충격소음 측정 시 정확한 측정을 위하여 3가지 측정방법을 동시에 측정할 수 있도록 구현하였으며, 정확성과 신뢰성을 위하여 3가지의 실내충격소음 측정값을 상호 비교하였다. 3가지 측정방법에 따른 최대 음압레벨과 옥타브 밴드 결과를 비교 분석함으로써 실내 충격소음의 주파수 특성에 따른 차이점을 확인하였다. 이러한 결과는 반사파의 영향에 의한 것으로 판단된다. 이에, 시험장의 크기를 변형하면서 측정할 수 있도록 실내 충격소음 측정시스템을 구현하였다. 본 시스템 구현을 통하여, 충격 소음원의 특징분석과 해당 주파수별 스펙트럼의 반사파 영향들을 파악할 수 있을 것이며, 향후, 실내 충격소음에 대한 데이터 획득 및 분석을 위하여 유용하게 활용될 수 있을 것으로 판단된다.

• 사상체질의학회지
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• 제17권1호
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• pp.84-102
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• 2005

Objectives The purpose of this study was to objectify the diagnosis of Sasang constitution. It was analyzed the adult female voices into 44 factors with PSSC-2004. Methods The study was conducted on the subjects inputted /a/ 2.5-3 sec of 217 adult women voices to PSSC-2004. The statistical analyses are applied to three groups: total group, under 55 year-old group, over 55 year-old group. The group of total 216 was composed with 8 Taeyangins, 60 Soyangins, 66 Taeumins and 83 Soeumins. The under 55 year-old group was composed with 6 Taeyangins, 53 Soyangins, 55 Taeumins and 76 Soeumins. The over 55 year-old group was composed with 2 Taeyangins, 7 Soyangins, 11 Taeumins and 7 Soeumins. Results 1. In total group and under 55 year-old one, Soeumin's center pitch were significantly high compared with the others(P=0.005)(P=0.019). It was significant for distinction between Taeumin and Soeumin at the result of post mortem. 2. In over 55 year-old group, Soeumin's center freq.(total) and center freq.(1) were significantly high compared with the others(P=0.024)(P=0.016). In under 55 year-old group, Soeumin's center freq.(4) was significantly high(P=0.025). While Taeumin's center freq.(3) in under 55 year-old group and center freq.(4) in over 55 year-old group were significantly high(P=0.049)(P=0.043). 3. In over 55 year-old group, Soeumin's APQ(center), APQ(2/5), APQ(3/5), APQ(4/5) and APQ(2/3) were significantly high compared with the others. It was significant for distinction between Taeumin and Soeumin at the result of post mortem(P=0.004) (P=0.003) (P=0.004) (P=0.013) (P=0.004). 4. In over 55 year-old group, Soeumin's APQ(1/3), APQ(1/2), APQ(2/2) and zeroover APQ were significantly high compared with the others (P=0.013) (P=0.003) (P=0.008) (P=0.012). 5. In over 55 year-old group, Taeyangin's octave 3 shimmer was significantly high compared with the others(P=0.000). 6. In under 55 year-old group, Taeyangin's total energy was significantly high compared with the others(P=0.040). 7. In under 55 year-old group, Taeyangin's zeroover energy sum was significantly high compared with the others(P=0.038). Conclusions From above result, there is the possibility of efficiency standard guide for constitutional diagnosis by analyzation of the voices.

• 한국지능시스템학회논문지
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• 제20권2호
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• pp.251-256
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• 2010

본 논문은 컬러이미지에서 소리를 연상하는 인간의 공감각적 기능을 모방하는 지능로봇의 개발을 위하여 색-음 상호변환에 기초한 응용 시스템의 구축을 목표로 하고 있다. 그 첫 번째 단계로서 컬러 이미지를 소리로 변환하는 방법론에 관한 기초 연구 및 이에 기반한 기본 시스템을 구현하고자 한다. 본 연구에서는 컬러 영상이 갖고 있는 색상과 소리의 파동, 즉 상호 주파수 특성에서의 유사성을 이용하여 가시영역에서 가청영역으로 변환하는 방법을 제시하고, 컬러모델 변환 및 변환된 모델에서의 히스토그램을 이용하여 컬러 영상을 소리의 청각적인 요소로 변환 가능하게 하는 색-음 변환 방법을 제시하고 있다. 또한 본 연구에서 제시된 색-음 변환 방법을 토대로 Microsoft Visual C++을 이용하여 코딩하고 실제 기본 응용 시스템을 구현해 보았다. 그 결과 색채와 소리의 상호 연관성 즉, 색채의 색상(Hue), 채도(Saturation)및 명도(Intensity)를 음의 높이(Fundamental Frequency), 하모닉(Harmonics) 및 옥타브(Octave)에 각각 대응시키고, 변환된 음향 요소를 Csound로 합성하여 웨이브 파일로 변환됨을 확인하였다.

• 월간산업보건
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• 통권5호
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• pp.4-15
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• 1988

In order to proffer the fundamental data for the better working environment and the effective establishment of hearing conservation program on workers exposed to industrial noise, author assessed noise levels on the 42 noisy processes among 84 manufactures of 9 industries and measured noise gearing loss by the type of industries on 3,104 workers at these noisy processes from March, 1986 to Februry, 1987. The results were summarized as follows: 1. The averge of A-weight sound level of 23 processes(54.8%) and the avergae of sound level at each octave band of 14 processes(33.3%) exceeded the permissible exposure limits in 8 hours per day. 2. The noise level was the highest in process of cocking of ship building(109.1dBA), and followed by plating of steel rolling(104.3dBA), rivet of manufacture of motor vehicles(102.5dBA), shot of ship building(98.5dBA), aciding(95.7BA) and steel tubing(95.0dBA) of steel rolling, weaving of textiles(95.0dBA). 3. The permissible exposure time for the average of sound level at each octave band was only 30 minutes in the process of cocking of ship building, plating of steel rolling and rivet of manufacture of motor vehicles. 4. As a result of audiometric examination in 3,104 workers, the rate of hearing loss over 50dB at 4,000Hz was 7.3%(227 workers) and the rate of hearing loss over 41dB at 60average method was 2.9%(89 workers). 5. The prevalence of occupational hearing loss in ship building and manufacture of motor vehicle was 5.2% and it was the highest among prevalence of these 9 industries. 6. As a result of this suvery, the noise control and gearing conservation program were required especially in the industry of ship building and manufacture of motor vehicle.

• 융합신호처리학회논문지
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• 제16권4호
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• pp.175-181
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• 2015

본 논문은 전파천문 관측데이터 분석을 위해 소프트웨어를 이용한 디지털필터 설계방법에 대해 제안한다. 전파천문 관측시스템은 컴퓨팅 시스템의 발전과 함께 하드웨어에서 소프트웨어를 이용한 분석방법으로 넘어가는 단계이다. 기존 하드웨어로는 특정규격에 맞도록 설계 제작되었기 때문에 규격을 변경하는 것이 어렵고 제작에 많은 비용이 소요되지만, 소프트웨어는 규격 변경이 유연하고 공개 소프트웨어를 이용할 경우 저렴하게 설계할 수 있는 장점이 있다. 그러나 소프트웨어로 전파천문과 같이 많은 자료를 분석하기 위해서는 컴퓨터 시스템의 성능이 우수해야 하는 점도 있다. 본 연구에서는 한국우주전파관측망에서 운영하고 있는 관측시스템 중에서 하드웨어로 구성된 디지털필터와 같은 성능을 갖는 소프트웨어 디지털 필터 설계에 대해 제안한다. 제안 방법은 표준 C언어를 이용하여 디지털 필터를 설계하였으며, 설계한 디지털필터에 대해 GNU Octave로 시뮬레이션을 수행하여 유효성을 검토하였다. 또한 설계한 디지털필터의 고속연산을 위해 병렬연산이 가능한 SSE 라이브러리를 도입하였다. KVN 관측모드 중에 광대역 관측데이터를 대상으로 제안한 방법의 디지털 필터를 통하여 협대역 관측모드로 데이터 필터링을 수행하였다. 그 결과, 대역 내의 필터링이 설계대로 수행되었고 리플이 발생하지 않아, 제안방법이 유효함을 확인하였다.

• The Journal of the Acoustical Society of Korea
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• 제17권2E호
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• pp.31-37
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• 1998

This paper proposes a feature extraction method using wavelet transform for speech recognition. Speech recognition system generally carries out the recognition task based on speech features which are usually obtained via time-frequency representations such as Short-Time Fourier Transform (STFT) and Linear Predictive Coding(LPC). In some respects these methods may not be suitable for representing highly complex speech characteristics. They map the speech features with same may not frequency resolutions at all frequencies. Wavelet transform overcomes some of these limitations. Wavelet transform captures signal with fine time resolutions at high frequencies and fine frequency resolutions at low frequencies, which may present a significant advantage when analyzing highly localized speech events. Based on this motivation, this paper investigates the effectiveness of wavelet transform for feature extraction of wavelet transform for feature extraction focused on enhancing speech recognition. The proposed method is implemented using Sampled Continuous Wavelet Transform (SCWT) and its performance is tested on a speaker-independent isolated word recognizer that discerns 50 Korean words. In particular, the effect of mother wavelet employed and number of voices per octave on the performance of proposed method is investigated. Also the influence on the size of mother wavelet on the performance of proposed method is discussed. Throughout the experiments, the performance of proposed method is discussed. Throughout the experiments, the performance of proposed method is compared with the most prevalent conventional method, MFCC (Mel0frequency Cepstral Coefficient). The experiments show that the recognition performance of the proposed method is better than that of MFCC. But the improvement is marginal while, due to the dimensionality increase, the computational loads of proposed method is substantially greater than that of MFCC.

• 한국음향학회지
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• 제36권2호
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• pp.144-150
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• 2017

음악 장르는 음악 검색 및 분류 등의 정보 처리 시스템 구현에 있어서 필수적인 요소이다. 일반적으로 장르 분류를 위한 스펙트럼 특징은 음악의 화음 및 강약 구조를 표현하기 위해 부밴드로 분해하여 구해진다. 본 논문은 음악 장르 분류 성능 개선을 위한 특징 추출을 위한 부밴드 분해 방법에 관해 연구하였다. 또한 부밴드 음악 특징의 차수를 줄일 수 있는 방법에 대해서도 연구하였다. 널리 사용되고 있는 장르 데이터셋들에서 실험을 수행하여 널리 사용되고 있는 옥타브 스케일보다 세분화된 부밴드 분해가 장르 분류 성능을 향상시킬 수 있으며, 특징 차수 축소를 결합하여 분류기의 계산량도 줄일 수 있음을 보였다.

• 한국소음진동공학회논문집
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• 제16권11호
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• pp.1124-1131
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• 2006

This paper presents a novel method to determine sound power level(PWL) emitted by a travelling vehicle for road traffic noise simulation. The PWL is evaluated by the equivalent sound pressure level (SPL) measured by close proximity method and the sound power correction factor derived from the maximum SPL measured by pass-by method and the propagation attenuation of vehicle noise during the pass-by measurement. Using the method, we derive the empirical formula for PWL estimation in 1/1-octave and overall frequency bands for 8 vehicles (automobile, SUV, small truck, large bus, trailer, 3 dump trucks) tested at two road surfaces (dense graded asphalt, 30mm transverse tinning concrete) of Korean highway test road. The suggested approach, if securing sufficient data to represent the acoustic characteristics of all vehicle types, has il strong merit to be able to evaluate sound power levels for any combination of vehicle categories and traffic volumes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.962-965
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• 2005

A high intensity progressive wave tube is installed at Korea Aerospace Research Institute (KARI) for acoustic environmental tests. The test facility has 700 mm x 800 mm cross-sectional area, and provides acoustic environment of 165 dB over the frequency range of $25Hz{\sim}10,000Hz$. The facility consists of a 6 m long acoustic wave tube, acoustic power generation systems, gases nitrogen supply systems, and acoustic control systems. This paper describes how the basic parameters of the facility and power generation systems are controlled to meet the requirement of the test. The shape and length of the tube has been designed by using the size of test objects and the wave propagation characteristics of the tube. The capacity of acoustic power generation systems is determined by the energy conversion of acoustic wave and the efficiency of acoustic modulators. Moreover, the paper introduces test run results of the tube. Overall of 163dB has been generated by using the test facility.

• 소음진동
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• 제4권3호
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• pp.377-384
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• 1994

This paper is an investigation of the performance of absorption diffusers to suppress the vent noise emitted when high pressure gas is throttled. First, experiment for the static performance is carried out. When there is no through-flow, the insertion loss has been obtained in terms of 1/3 octave band spectrum and the effect of the number of diffusers and the thickness of the absorption material on the static performance has been obtained. And the similarity in the spectrum of the static insertion loss is confirmed by comparing two similar models with different size. Second, the dynamic performance has been obtained by experiment using blow-down of compressed air from a storage tank through an orifice of diameter 10 mm. The back pressure by the diffuser is measured and compared with that of a single diffuser. It is found that the insertion loss of asingle diffuser is very low around 3 dB at high frequencies with negative value at low frequencies. By absorption material between the diffuser tubes, however, the performance is increased considerably. Without flow the static insertion loss increases by 3 - 4 dB by doubling the thickness or the density of the absorptionmaterial. With flow, however, the dynamic insertion loss increases. While, the back pressure by the diffuser is small enough to be neglected.