• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.237-243
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• 2004

A multichannel smart sound sensor capable to detect and identify sound events in noisy conditions is presented in this paper. Sound information extraction is a complex task and the main difficulty consists is the extraction of high­level information from an one-dimensional signal. The input of smart sound sensor is composed of data collected by 5 microphones and its output data is sent through a network. For a real time working purpose, the sound analysis is divided in three steps: sound event detection for each sound channel, fusion between simultaneously events and sound identification. The event detection module find impulsive signals in the noise and extracts them from the signal flow. Our smart sensor must be capable to identify impulsive signals but also speech presence too, in a noisy environment. The classification module is launched in a parallel task on the channel chosen by data fusion process. It looks to identify the event sound between seven predefined sound classes and uses a Gaussian Mixture Model (GMM) method. Mel Frequency Cepstral Coefficients are used in combination with new ones like zero crossing rate, centroid and roll-off point. This smart sound sensor is a part of a medical telemonitoring project with the aim of detecting serious accidents.

• 한국음향학회지
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• 제41권3호
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• pp.302-311
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• 2022

방음벽은 도심구간의 도로 및 철도에서 환경소음 저감을 위한 가장 효율적 대안의 하나이다. 도로교통소음 등에 대한 방음벽의 삽입손실은 방음판의 음향투과손실, 흡음손실 및 방음벽의 회절감쇠에 의한 음에너지 저감량의 합으로 이루어진다. 방음판의 음향투과손실은 방음벽의 삽입손실을 결정하는 중요한 요인 중 하나로 방음벽의 성능을 결정하는 기본적인 지표이다. 그럼에도 불구하고 아직까지 우리나라는 방음판의 음향투과손실 측정방법에 관한 별도의 규격이 없다. 방음판의 일반적 재질에 대해 규정하고 있는 KS F 4770 시리즈의 한두 항목으로 가볍게 다루고 있을 뿐이다. 이 논문은 방음판의 음향투과손실 측정 및 평가 규격의 필요성에 대해 고찰하고, 실내 건축부재와 달리 외부공간에 설치되는 방음벽의 특성을 감안한 자유음장(무향실) 수음실에서의 측정방법을 모색하였다. 아울러 도로변이나 철로변 등 다양한 설치장소에 따른 방음효과를 간단히 표시할 수 있도록 기준 스펙트럼을 활용한 단일수치 평가법을 제안하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제12권2호
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• pp.21-34
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• 1988

Machinery enclosures are widely adopted to reduce the noise emission in various fields of application. Emitted noise, which is due to the vibration of enclosure's outer surface, is composed of two kinds of sound with different path of propagation. One is the "structure-borne sound", while the other is "air-borne sound". In order to get a most efficient machinery enclouser a prudent consideration upon the above structure-borne and air-borne sound is required, as the guiding principle of contermeasure for each noise is quite different. The controlling of input vibration and its isolation are major subjects for the structure-borne sound, and the specifications of absorbing members and damping panels are the major related matters for the air-borne sound. Hence, it seems very efficient to separate the total sounds into two categories with a great accuracy when one think of further reduction of noise from the existing enclosure, although its separating methods have not been made clear for many years. Author proposes an application method of experimental modal analysis to extract the structure-borne sound from the measured total radiation sound, as the air-borne sound is deduced by the vectorial difference between the measured total radiation sound and the calculated structure-borne sound. In order to calculate the correct structure-borne sound by the excitation at an arbitrary point on the enclosure structure, it is important to decide 1) how to estimate the enclosure's surface vibration velocity and 2) how to compute the radiation sound which is considered as the effect of vibration modes of enclosure surface. The former can be solved with total frequency response function calculated by the application of experimental modal analysis. The latter is to be solved by the author's new approaches for radiation sound computation by means of the Rayleigh's integral equation and the boundary-element method applied complex surface vibration velocity. As a first step, structure-borne sound by the excitation at an arbitry point on the rectangular plate with fixed edges, has been calculated to verified the reliability of the developed computation methods. The results of calculation show good agreements with those of the actual measurements.actual measurements.

• 한국컴퓨터정보학회논문지
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• 제28권9호
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• pp.55-62
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• 2023

본 논문에서는 기하학 기반의 사운드 생성 기법을 활용하여 1)다중 음원, 2)바람의 이류와 3)온도에 따른 상호작용을 효율적으로 처리할 수 있는 방법을 제시한다. 최근에 절감된 광선추적법(Reduced raytracing) 기반으로 사운드(Sound) 위치를 업데이트하고 많은 레이(Ray)의 재귀적인 반사/굴절 없이 사운드 전파와 회절을 효율적으로 계산하는 방법이 제안되었지만, 이 접근법은 사운드의 전파 특징만을 고려했지 다중 음원, 바람의 이류와 온도에 따른 상호작용은 고려하지 못했다. 이러한 한계는 정적인 사운드만 생성하기 때문에, 다양한 가상환경에서 사운드를 통한 장면 제작을 어렵게 만든다. 본 논문에서는 여러 개의 사운드가 배치된 상황에서 사운드 맵을 효율적으로 구성할 수 있는 방법과 이것을 통해 효율적으로 에이전트의 움직임을 제어할 수 있는 방법을 제시한다. 뿐만 아니라 바람의 이류와 온도를 고려하여 사운드 전파를 제어를 할 수 있는 방법을 제안한다. 본 논문에서 제안하는 방법은 사운드를 기반으로 콘테츠 몰입을 개선시킬 수 있는 게임뿐만 아니라 메타버스 환경 디자인, 군중 시뮬레이션 등 다양한 분야에서 활용이 가능하다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.727-732
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• 2009

The objective of this study is to analyze and evaluate design factors relating to sound reduction performance in dry wall system. The main contents of this study are as follows. 1) Analysis and pre-evaluation of sound reduction performance of drywall system ; The sound reduction performance was pre-evaluated by INSUL simulation and these results of analyzing walls were analyzed by screening DOE(design of experiment) for selecting major factors that dominant influence the sound reduction performance. These main factors relating to sound reduction performance can be used for development of 1st grade sound reduction performance drywall system. 2) Design and evaluation of 1st grade sound reduction performance drywall system; The evaluation test of the sound reduction performance gave vaues higher than 1st grade (Rw+C=64). When campared with existing dry wall system, respectivelly, the new system shows performance higher than 8 dB.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 추계학술대회 논문집
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• pp.586-591
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• 2010

The sound field can be classified to the direct and reverberant sound field. If the sound absorption material in a room is not applied sufficiently, the reverberant sound field increases and the sound pressure in a room also increases when the sound source exists in a room. Therefore, the reverberation time should be controled in order to reduce the reverberant sound as well as sound pressure level in a room. Even though the reverberation time is specified and researched widely in architectural engineering, it is rarely performed in a marine engineering. Therefore, in this research, the reverberation time in a navel vessel is researched related to the noise reduction in a cabin.

• 환경영향평가
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• 제14권4호
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• pp.217-225
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• 2005

In apartment buildings, floor-impact sound has bean regarded as the major source which induces complaints from residents. It is mainly due to the use of light-weight structures. The vibration produced by impact on one part of an apartment building would travel as far as the other parts of structure with a little alleviation. As a result, the impact sound from upstairs has been regarded as a main source of noise causing discontentment among occupants. This study was carried out to measure the floor-impact sound levels and evaluate the insulation performance of floor-impact sound for nine apartment buildings. The floor-impact sound levels were measured for twenty-five On-dol floor structures and various factors which influence the floor-impact sound were analyzed.

• 한국염색가공학회지
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• 제23권4호
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• pp.304-311
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• 2011

For sound absorption and sound insulation in automobile industry, the sound absorption materials based on meltblown nonwovens were prepared by SMS (spunbond-meltblown-spunbond) technique. And the sound absorption coefficient (${\alpha}$) of the meltblown nonwoven, produced with isotatic-polypropylene(PP), was examined for the various processing conditions such as die-to-collector distance(DCD), nonwoven weight(GSM), and air suction conditions. The meltblown nonwoven for sound absorption materials was composed of bulky microfiber web, increasing with increases in weight and DCD. The sound absorption coefficient(${\alpha}$) was excellent as a sound absorption materials of PAD type composed of SMS(spunbond-meltblownspunbond) nonwovens.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.92-99
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• 1998

The sound insulation capacity of honeycomb sandwich plates which have relatively higher strength ratios to weight is poorer than those of uniform and another sandwich plates. Therefore, improvement of the sound insulation capacity of the honeycomb sandwich plate which has a meritof lightness is required to use it in automobile and rapid rail road industries. In this study, to improving the sound insulation capacity of the honeycomb sandwich plate, the sound transmission loss of the structure is experimentally investigated by adding a viscoelastic damping layer, The effective add position and thickness of the layer were investigated from the viewpoints of both sound transmission loss and improved sound transmission loss over the frequency range from 800Hz to 10kHz.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.492-497
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• 2006

This study gives the results of the measurements and analysises of the reverberation times in a small room such as apartment houses. We measured the RT by changing measurement conditions, which were sound sources. sound source's positions, receiving point & height, sampling time and so on. The critical factor affecting reverberation time was sound source in unoccupied houses and the reverberation time differences between result of RT using impulsive and interrupted sound source was 0.3sec at 500Hz frequency. And the difference of RT due to sound sources affected the sound insulation such as apparent sound reduction index and sound level difference about 1dB at each frequency in unoccupied houses.