• Title/Summary/Keyword: 실내음향

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Evaluation of Interior Sounds of High-speed Trains Considering the Condition of Tunnel Running (터널 주행을 고려한 고속열차의 실내소음 특성 평가)

  • Kim, Jae Ho;Kim, Ho Jun;Jeon, Jin Yong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.3
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    • pp.253-260
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    • 2014
  • conducted. In-situ measurements were conducted to investigate the noise characteristics in high-speed trains such as KTX and KTX-Sancheon. Binaural microphones and spherical microphone were adopted to record and evaluate the spectral characteristics and noise incidence characteristics at the seats in the passenger cars. Environmental elements were also recorded during the noise measurements using a camcorder and GPS application. In addition, auditory tests were conducted to investigate annoyance of interior noise of high-speed trains. Based on the objective measure and subjective responses on interior noise, statistical analysis such as correlation and regression analyses were carried out. From the results perception models for evaluating the interior noise of high-speed train were derived.

Optimum Design of the Microphone Sensor Array for 3D TDOA Positioning System (3차원 TDOA 위치인식 시스템의 마이크 센서 배열 최적 설계)

  • Oh, Jongtaek
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.1
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    • pp.31-36
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    • 2014
  • A study on the indoor positioning system has been active recently for the location based service indoors. In the 3 dimensional positioning system based on the acoustic signal and TDOA technology, the error characteristics of the estimated source position would be changed depending on the number of microphones and the pattern of the microphone array. In this paper, the estimated position error according to the measured distance error between the microphones and the signal source is analyzed, and the optimum microphone array is decided considering the estimated position error patterns and the total amount of the estimated position error.

A Study on the Space Design of the Virtual Reality Simulation Exclusive Space (가상현실(VR) 시뮬레이션 전용관 공간설계에 관한 연구)

  • 임종엽;유태관
    • Korean Institute of Interior Design Journal
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    • no.33
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    • pp.115-121
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    • 2002
  • This study is based on the Virtual Reality Space what grow rapidly compared with other space type. We make a certain definite possibilities by the functional, material, scientific and conceptual space comparison approved with existing visual space about the function of sound and visual system & the application of the mechanical system. Symbol and Expression Media are showing characteristics more than a tool in Modern times being changed from materialistic world to immaterial one. Especially, Augmented Reality, which is the new technology showing human beings real world and virtual world simultaneously recently and being exceeded to existent many limits, is going ahead. Simulation space is the technology one which can be applied to various fields such as culture, industry and education etc., and it helps human beings to overcome their limitations. The gains from this study are the specified and detailed yardsticks and cases of Simulation(space) facilities classified as a specific space. Therefore, the space mainly consists of the parts on size, equipment, and material etc. judging from technical point of view. Architectural Space, especially, should be considered very importantly in the middle of the transition from image realization to experience. The comprehension on various contents together with mechanical facilities will be requested to the connection applied to physical space expression, and that is what we have to study continuously afterward.

A Study on the Architectural Characteristics of Vuoksenniska Church (부오크세니스카 교회의 건축 특성에 관한 연구)

  • Chung, Tae-Yong
    • Korean Institute of Interior Design Journal
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    • v.18 no.1
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    • pp.19-26
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    • 2009
  • Aalto designed his own modern architecture in comparison with other modern architects of his days. It is because Aalto went beyond the principle of dogmatic functionalism based on his attitude not to copy images of functionalism but to fulfill function of the building. He decided architectural form and space according to logical basis including the effective use of light and sound. Vuoksenniska church, as is called the most exceptional and notable church in his works, was designed based on the fulfillment of program. As he knew that the program needed the extension of the main church space into social areas, he put emphasis on individuality of space rather than the wholeness of space. Sound and light analysis of Vuoksenniska church shows that Aalto tried to have adequate environment of each space at the start and Integrate them later. The spatial configuration of Vuoksenniska church shows that the individuality of space has priority over the wholeness of spaces. Discordance between roof form and ceiling is the best example for this matter. Aalto designed various windows that have different sizes, figure and location to induce desirable light for each space of the church. He also adjusted the shape of the ceiling and the angle of wall for a effective sound transmission. This result indicates that he knew the activity of the church is normally confined to one weekly morning and the whole space Is hardly used as a religious purpose.

Noise Attenuation by Landscape Woody Plants - Comparisons as a Hedge Species Between Japanese Spindle Tree & Oriental Arbor-vitae - (조경수목(造景樹木)의 소음감쇠효과(騷音減衰効果)에 관(關)한 연구(硏究) - 사철나무와 측백나무 수벽(樹壁)의 비교분석(比較分析) -)

  • Kim, Yong Shik;Chang, Ho Gyeong;Kim, Ye Hyun
    • Journal of Korean Society of Forest Science
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    • v.78 no.1
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    • pp.30-34
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    • 1989
  • Effects on noise attenuation of the hedge species, Thuja orientalis L. and Euonymus japonicus Thunb., widely used as road side hedges, were analysed at the frequencies of 1,000, 2,000 and 3,150 Hz., respectively. The present experiments were carried out both in the field and in a Semianechoic Chamber. As increasing the distances from the noise source, attenuation rates of noise level were increased at high frequencies. But the attenuation rates of the noise level at low frequencies showed varied as the distances increased, and this trend appeared to be caused by the influence of ground waves. Generally, in this experiment, Thuja orientalis L., which is a coniferous species, showed more effective on the abilities of noise attenuation than that of Euonymus japonicus Thunb., which is a broad-leaved evergreen species.

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An Experimental Study on the Optical Separation of Highly Concentrated Sunlight (Hot mirror를 이용한 고밀도 태양광의 광분리에 관한 기초실험 연구)

  • Kim, Yeongmin;Mo, Yonghyun;Shin, Sangwoong;Oh, Seungjin;Chun, Wongee
    • Journal of Energy Engineering
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    • v.23 no.4
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    • pp.56-60
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    • 2014
  • Highly concentrated sunlight obtained from a solar concentrator mounted on a solar tracker can be divided into the infrared and visible region before it is actually applied. That is, solar rays are directed toward a unit optically separating sunlight into the infrared and visible region by a hot mirror as they impinge on the surface of a secondary reflector. The Infrared rays can be utilized for thermoacoustic applications while visible rays can be utilized for indoor lighting. This work introduces the separation of two different kinds of light; sunlight and artificial light. As for the artificial light, its wavelength extended from 400m to 720m for the visible region and 620m to 940m for the infrared region. Comparatively, a series of tests performed on sunlight revealed its separation in the visible region from 460m to 680m whereas from 620m to 940m for the artificial light.

A study on A-pillar & wiper wind noise estimation using response surface methodology at design stage (반응면 기법을 이용한 A필라/와이퍼 풍절음 예측 연구)

  • Rim, Sungnam;Shin, Seongryong;Shin, Hyunsu
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.5
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    • pp.292-299
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    • 2018
  • The vehicle exterior design is the main parameter of aerodynamic wind noise, but the modification of it is nearly impossible at a proto-type stage. Therefore, it is very important to verify exterior design and estimate the correct wind noise level at the early vehicle design stages. The numerical simulations of aerodynamic wind noises around A-pillar and wiper were developed for specific vehicle exterior designs, but could not be directly used for the discussions with designers because these need complex modeling and simulation process. This study proposes new approach to A-pillar and wiper wind noise estimation at design stage using response surface methodology of modeFRONTIER, of which database is composed of PowerFLOW simulation, PowerCLAY modeling, SEA-Baced (Statistical Energy Analysis-Based) interior noise simulation, and turbulent acoustic power simulation. New design parameters are defined and their contributions are analyzed. A state-of-the-art, easy and reliable CAT (Computer Aided Test) tool for A-pillar and wiper wind noise are acquired from this study, which shows high usefulness in car development.

Prediction of Heavy-Weight Floor Impact Sound in Multi-unit House using Finite Element Analysis (유한요소해석을 이용한 공동주택의 중량충격음 예측)

  • Mun, Dae-Ho;Lee, Sang-Hyun;Hwang, Jae-Seung;Baek, Gil-Ok;Park, Hong-Gun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.6
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    • pp.645-657
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    • 2015
  • In this study floor impact noise and structure acceleration response of bare concrete slabs were predicted by using Finite Element Analysis(FEA). Prediction results were compared with experimental results to prove the accuracy of numerical model. Acoustic absorption were addressed by using panel impedance coefficients with frequency characteristics and structural modal damping of numerical model were applied by modal testing results and analysis of prediction and test results. By using frequency response function, the floor acceleration and acoustic pressure responses for various impact sources were calculated at the same time. In the FEA, the natural frequencies and the shapes of vibration and acoustic modes can be estimated through the eigen-value analysis, and it can be visually seen the vibration and sound pressure field and the contribution of major modes.

Effect of the Inter-aural Level Differences on the Speech Intelligibility Depending on the Room Absorption in Classrooms (실내 흡음에 따른 양이간 음량차가 강의실의 음성명료도에 미치는 영향)

  • Park, Chan-Jae;Haan, Chan-Hoon
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.4
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    • pp.335-345
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    • 2013
  • The present study investigates the effect of the inter-aural level difference(ILD) on the syllable articulation test in classrooms which can be occurred by the absorption of interior surfaces. In order to do this, the sound absorbing materials were installed in the classroom and sound pressure level(SPL) at each ear was measured using binaural recording systems. Also, syllable articulation tests were carried out at a classroom with and without sound absorption materials by 20 students who have normal hearing condition, in order to investigates the effect of the ILD on the speech intelligibility. As a result, it was found that the larger inter-aural level differences was occurred at the nearer positions to lateral walls after sound absorptions were applied to lateral walls in the classroom. At some places, the measured ILD was lager than JND of sound level (3dB). Also, it was shown that the correlation coefficient of inter-aural level difference with the score of syllable test has the significant result(-0.441). Thus, It is concluded that ILD can affect the subjective speech intelligibility in classrooms.

Modeling of Acoustic Echo Canceller Using Subband Adaptive Signal Processing (서브밴드 적응신호처리를 이용한 음향 에코제거기의 모델링)

  • Kim, Chun-Duck;Sim, Dong-Youn;Chung, Ho-Moon;Lee, Jun-Ku;Cha, Kyung-Hwan
    • The Journal of the Acoustical Society of Korea
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    • v.16 no.5
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    • pp.43-49
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    • 1997
  • Generally, echo cancelers of a TV conference system or a audio conference system are to carry out a real time processing in the case of the closed room having long reverberation time because the system requires much time to modify filter coefficients to environmental changes. Therefore this paper proposes a new subband adaptive filtering method using polyphase filter banks of MPEG(Moving Picture Experts Group) audio system to solve the problems. This method divides signal spectra of input and output into several frequency bands, and each band is adaptively filtered by using ES-NLMS (Exponential Step-Normalized Least Mean Square) algorithm. The optimal number of subband is determined by computational simulations. According to the results of simulation, ERLE of the subband model is 2dB smaller than general full band, calculation rate's of the subband model is decreased about 88%.

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