• Proceedings of the Korea Society of Design Studies Conference
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• 2002.05b
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• pp.266-267
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• 2002

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 1994.05a
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• pp.11-17
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• 1994

The increase of road traffic niose in residential area has been considered to be a serious environmental problem to deteriorate a living condition. The understanding of noise environment in multiple family housing is needed for noise reduction. This study attempts to find out the characteristics of noise environment. For this purpose, the field survey has been carried out to investigate the noise environment(sound level, quality of sound) and the residents' responses(noiseness, annoyance) for noise environment based on 173 households living in 3 apartment compounds built in Pusan according to site location. The major findings are as follows : 1. The sound levels by road traffic noise were measured by dB(A) and dB(Lin). The sound levels were : 77.0dB(A), 86.6dB(Lin) in D-Apt, 73.3dB(A), 82.6dB(Lin) in K-Apt, and 59.1dB(A), 74.6dB(Lin) in M-Apt. Especially, the difference between dB(A) and dB(Lin) was very big in the cae of M-Apt with a barriers for traffic noise reduction. 2. The internal sound levels were shown the soudn attenuation by horizontal distance and by opening or shuting condition of windows.

• Journal of the Korean Institute of Navigation
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• v.22 no.3
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• pp.17-25
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• 1998

This paper describes elemental technologies for the creation of three-dimensional(3-D) sound-field to implement the next-generation Ship Handling Simulator with human -computer interaction, known as Virtual Reality. In the virtual reality system, Head-Related Transfer Functions(HRTF's) are used to generate 3-D sound environmental context. Where, the HRTF's are impulse response characterizing the acoustical transformation in a space. This work is divided into two parts, the part Ⅰis mainly for the model constructions of the HRTF's, the part Ⅱis for the control of 3-D sound-field by using the HRTF's . In this paper, as first part, we search for the theory to formulate models of the HRTF's which reduce the dimensionalityof the formulation without loss of any directional information . Using model HRTF's we report results from psychophysical tests used to asses the validity of the proposed modleing method.

• The Journal of the Acoustical Society of Korea
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• v.42 no.6
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• pp.617-626
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• 2023

This study aims to investigate the preferred sound level of water sound for various levels of open-plan-office noise regarding soundscape quality and speech privacy. And assessment of the work efficiency of the water sound. For the laboratory experiment, office noise was recorded using a binaural microphone in a real open-plan office. For the assessment of the soundscape quality and speech privacy, Overall Soundscape Quality (OSQ) and Listening Difficulty (LD) were evaluated under three different sound levels (55 dBA, 60 dBA, and 65 dBA) and five different signal-to-noise ratios (SNR -10 dB, -5 dB, 0 dB, +5 dB, and +10 dB). After the evaluation, the preferred SNR was proposed according to OSQ and LD. For the assessment of to work efficiency of water sound, this study evaluated the cognitive performance of both of the condition noise only and combine the water sound with office noise. The results showed that LD increased as the water sound level increased, but OSQ decreased. When the water sound level was more than the office noise level, the OSQ decreased from noise only. Therefore, considering OSQ and LD, the preferred SNR of water sound was -5 dB for all noise levels. At the preferred level of water sound, the cognitive performance results were shown to decrease at 55 dBA compared to noise only, but at 60 dBA and 65 dBA combine the water sound results were increased than the noise only.

• MALSORI
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• no.59
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• pp.89-99
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• 2006

This paper proposes a new structural head-related transfer function(HRTF) model to produce sounds in a virtual environment. The proposed HRTF model generates 3-D sounds by using a head model, a pinna model and the proposed distance model for azimuth, elevation, and distance that are three aspects for 3-D sounds, respectively. In particular, the proposed distance model consists of level normalization block distal region model, and proximal region model. To evaluate the performance of the proposed model, we setup an experimental procedure that each listener identifies a distance of 3-D sound sources that are generated by the proposed method with a predefined distance. It is shown from the tests that the proposed model provides an average distance error of $0.13{\sim}0.31$ meter when the sound source is generated as if it is 0.5 meter $\sim$ 2 meters apart from the listeners. This result is comparable to the average distance error of the human listening for the actual sound source.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.51.3-51
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• 2002

3D sound user often finds the results that the sound image appear to originate either inside, or close to, the head when he uses headphone-based binaural system. This phenomenon is called in-head localization(IHL). The main factors were chosen to evaluate externalization performance : individualized HRTFs, near-field HRTF characteristics and reverberation. Direct comparison was conducted among them, especially two factors\ulcorner reverberation and near-field HRTFs.

• 한국해양학회지
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• v.20 no.2
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• pp.10-21
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• 1985

The sound velocity (compressional wave) and attenuation coefficient in the marine surface sediments in the nearshore areas off the Pohang, Pusan, Yeosu and Kunsan were investigated in terms of the geotechnical properties of the marine surface sediments in the water depth range of 10-50 meters. The marine surface sediments in the study areas are variable, that is, sand to clay. Due to the various four different study area, the sound velocities and attenuation coefficients in the surface sediment facies vary 1,44m/sec to 1,510m/sec in velocity and 0.82dB/m to 3.70dB/m in coefficient respectively. In fact, the sound velocity increases with increasing of density and mean grain sizes of the sediments, and however, with decreasing of porosith. The correlation equations between the sound velocith and geotechnical properties of mean grain size, density, and porosity were expressed as the following: Vp=1512.28406-9.16083(Mz)＋0.20795(Mz)$\^$2/, Vp=1876.15527-597.50397(d)＋210.48375(d)$\^$2/, Vp=1559.47217-2.09266(n)$\^$2/. where Vp is sound velocity, Mz is mean grain size, d is density, and m is porosity, respectively. However, the relationship between the attenuation and geotechnical properties were different from that of sound velocity and geotchnical properties. Furthermore, the correlation equations between attenuation coefficient and geotechnical properties were expressed as the following: a=1.85217＋0.67197(Mz)-0.09035 (Mz)$\^$2/, a=48.87859＋58.21721(d)-16.3.143(d)$\^$2/, a=2.06765＋0.07215(n)-0.00111(n)$\^$2/, where a is attenuation coefficient. The high attenuation appeared in the silty sand through fine sand facies in sediment and k values in these facies were in the range of 0.86 to 0.89 dB/m/KHz.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.2
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• pp.71-75
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• 1982

The feeding sounds of three fishes, Lateolabrax japonicus, stephanolepis cirrhifer and Fugu vermicularis were recorded in the tank, and the frequency and the sound pressure level were analyzed. The recorded sounds were emitted again into the tank and the response of fishes were observed. The results obtained are summarized as follows: 1) The frequency and the sound pressure level of the feeding sound of Lateolabrax japonicus, Stephanolepis cirrhifer, and Fugu vermicularis are 80~350 Hz and 250~500 Hz, and 101~103 dB, 106~115 dB and 102~112dB. 2) It was most effective to increase the sound pressure level as much as dB that make the fishes respond positive reaction to the feeding sound. 3) Lateolabrax japonicus and stephanolepis cirrhifer showed positive response and Fugu vermicularis showed little to the emitted feeding sound. 4) The fishes showed positive response to the sound until 5 minutes and then showed negative response, as the sound emitting succeed 10 minutes.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.61-67
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• 2004

This paper describes Three-Dimensional Listening Simulation System (3D-LSS) which is to analyze whistle sound related marine casualties, and is to evaluate the accident situations using 3D sound by Head Related Transfer Function. At first, the three-dimensional listening model from the analysis of accident situations is proposed, and then the reproduction and evaluation methods of 3D sounds are also discussed. The system is designed to explain the accident situations and to simulate the possible situations with GUI based graphics and 3D sound reproduction. The evaluation experiments using 3D-LSS are carried out with six cases that did not known whether it is true or not the blast and listening of the whistle sound between two vessels. As results of psychological assessments by five subjects, the six cases can be analyzed clearly by visual images and audio sounds, thus the usability of 3D-LSS as one of the judgment assistant system of marine casualty is verified.

• Journal of Navigation and Port Research
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• v.28 no.8
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• pp.659-666
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• 2004

This paper describes Three-Dimensional Listening Simulation System (3D-LSS) which is to analyze whistle sound related marine casualties, and is to evaluate the accident situations using 3D sound by Head Related Transfer Function At first, the hree-dimensional listening model from the analysis of accident situations is proposed, and then the reproduction and evaluation methods of 3D sounds are also discussed. The system is designed to explain the accident situations and to simulate the possible situations with GUI based graphics and 3D sound reproduction. The evaluation experiments using 3D-LSS are carried out with six cases that did not known whether it is true or not the blast and listening of the whistle sound between two vessels. As results of psychological assessments by five subjects, the six cases can be analyzed clearly by visual images and audio sounds, thus the usability of 3D-LSS as one of the judgment assistant system of marine casualty is verified.