• 산업기술연구
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• 제38권1호
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• pp.1-7
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• 2018

This paper introduces the design, casting, and sound evaluation results of the Great Bell of 2018 Pyeongchang Winter Olympics. The Olympic Bell was manufactured to announce the opening of the successful Winter Olympics in the world with a grand sound. The bell was designed to the dynamic shape to give a grand and harmonious sound in consideration of the global sports festival. In this study, the performance of the beat making the sound magnificent and the harmony of the bell sound were quantitatively evaluated using acoustical factors. Beat maps were investigated to understand the directivity of the beating sound. The purpose of the research is to present the production technique of a traditional Korean bell that has a dynamic shape and a grand and harmonious sound.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.121-124
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• 2014

Many of research on noise reduction techniques have been progressed for the improvement of noise environment in subway train. There are many way to noise reduction techniques in the tunnel, but it has been reported as an alternative to attach sound absorption material on tunnel wall. For this reason sound absorption material has been studied for application of tunnel. The objective of this study is to investigate design parameters on a Helmholtz resonator with built-in sound absorption panel for the reduction of the tunnel noise in the subway. Sound absorption panel composed of the perforated panel with sub-millimeter holes and the airspace backed a rigid wall or between panels. The experiment is performed through the change of number of perforated panel, cross sectional area and the depth of airspace of the sound absorption panel under the normal incidence sound.

• International journal of advanced smart convergence
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• 제9권4호
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• pp.101-105
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• 2020

In this study, we are going to discuss the role of sound, which exists as the background of a movie scene, and the relationship between seeing and hearing. In order to analyze the form in which the scene and sound are matched, the visual content of the image must be analyzed first. In this study, we analyzed Stanley Kubrick's film . Generally, there are both visual and auditory features in the scene of the movie. In some cases, the sound is emphasized more than the scene, and the scene is emphasized more than the sound. In particular, the sound in movies enables a wider imagination and a three-dimensional experience. Images and sounds will have different meanings and effects depending on the purpose of use. By analyzing the correlation between visual scene and auditory sound based on the role sound plays in the film in this study, we would like to confirm that sound is one essential element that has the role of equivalent and independent expression, not the role of assisting images.

• 한국소음진동공학회논문집
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• 제25권9호
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• pp.614-619
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• 2015

The purpose of this study is that developing the index which evaluate sound quality of door latch and improving its sound quality through that results. For that, various operating sound of door latch was used for jury test. Loudness and sharpness related metrics are dominant in sound quality index we developed. This research investigate the main transfer path of its operating sound through sound field visualization and get conclusion that could reduce the impact sound of door latch. Therefore, we could verify sound quality improvement of modified product by using sound quality index.

• 한국소음진동공학회논문집
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• 제22권2호
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• pp.103-114
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• 2012

Nowadays membrane material is widely used for large indoor spaces and long spaces such as traditional market. Thermal insulation and sound field control performance is considered as a main properties for design of such buildings. In this paper sound absorption and thermal insulation properties of membrane material was investigated. Firstly, normal incidence sound absorption coefficient of 10 kinds of glass wool textiles showed that sound absorption coefficient was increased in proportion of thickness and surface density of textile. Sound absorption coefficient of 4 kinds of sound absorptive inner membrane with outer membrane was tested in the reverberation chamber. Sound absorption coefficient of mid frequency range was about 0.4 ~ 0.6. Also, sound absorption coefficient was changed by the air space behind the membrane material. Secondly, sound field control performance was investigated using mock-up space. By the installation of sound absorption membrane material, reverberation time was decreased and speech intelligibility was increased. Finally, thermal resistance and room temperature in two kinds of mock-up rooms were tested, simultaneously. Results of thermal properties showed thermal insulation properties ware increased by adding inner membrane material underneath the outer membrane.

• 대한산업공학회지
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• 제35권1호
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• pp.101-108
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• 2009

This study aims to design ergonomic warning sound that is not confusing and enhancing preference. Four factors of the warning sound represented as interval, chord, reverberation and pitch were selected as independent variables. And, perceived urgency, perceived criticality, degree of confusion and user preference are measured as dependent variables. An experiment was conducted in silent lab environment. Warning sounds were given in 90dB constantly to subjects through stereo speakers. A statistical analysis revealed that interval was significant for perceived urgency; also interval and chord were both effective for perceived criticality. Pitch, interval, chord and the interaction between pitch and chord were effective in degree of confusion, so were reverberation, the interaction between reverberation and pitch and the interaction between reverberation and chord for preference. This study characterized the situation under which warning sounds are required into three types in terms of urgency and criticality; and found the right warning sound that the subjects perceived to best represent the situation through the validation study. These findings are expected to help the designer choose the right warning sound according to the situational contexts in which such warning sounds are implemented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.728-733
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• 2008

Though multi-panel structures lined with a poroelastic material have been widely used to reduce sound transmission in various fields, most of the previous works to design them were conducted by repeated analyses or experiments based on initially given configurations or sequences. Therefore, it was difficult to obtain the optimal sequence of multi-panel structures lined with a poroelastic material yielding superior sound isolation capability. In this work, we propose a new design method to sequence a multi-panel structure lined with a poroelastic material having maximized sound transmission loss. Being formulated as a one-dimensional topology optimization problem for a given target frequency, the optimal sequencing of panel-poroelastic layers is systematically carried out in an iterative manner. In this method, a panel layer is expressed as a limiting case of a poroelastic layer to facilitate the optimization process. This means that main material properties of a poroelastic material are treated as Interpolated functions of design variables. The designed sequences of panel-poroelastic layers were shown to be significantly affected by the target frequencies; more panel layers were used at higher target frequencies. The sound transmission loss of the system was calculated by the transfer matrix derived from Biot's theory.

• 한국소음진동공학회논문집
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• 제21권11호
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• pp.1059-1066
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• 2011

The micro-perforated panel absorber(MPPA) is one of promising noise control elements because of its applicability to extreme environments where general porous materials cannot be used. Since the MPPA is inherently non-porous sound absorber, it can be a good candidate of acoustic protection system of a space launcher. The overall sound pressure level inside payload fairings of commercial launch vehicles is so high(around 140 dB OASPL) that the conventional linear impedance model cannot be directly applied to the design of the acoustic protection systems. In this paper an acoustic impedance models of a micro-perforated panel absorber at high sound pressure environment were reviewed and the use of the impedance on the practical design of MPPAs was addressed. The variation of absorption characteristics of MPPA was discussed according to the design parameters, e.g., perforation ratio, the minute hole diameter, the thickness of MPP and the incident sound pressure level.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.178-185
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• 2011

The micro-perforated panel absorber (MPPA) is one of promising noise control elements because of its applicability to extreme environments where general porous materials cannot be used. Since the MPPA is inherently non-porous sound absorber, it can be a good candidate of acoustic protection system of a space launcher. The overall sound pressure level inside payload fairings of commercial launch vehicles is so high (around 140 dB OASPL) that the conventional linear impedance model cannot be directly applied to the design of the acoustic protection systems. In this paper an acoustic impedance models of a micro-perforated panel absorber at high sound pressure environment were reviewed and the use of the impedance on the practical design of MPPAs was addressed. The variation of absorption characteristics of MPPA was discussed according to the design parameters, e.g., perforation ratio, the minute hole diameter, the thickness of MPP and the incident sound pressure level.

• 전기학회논문지
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• 제65권7호
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• pp.1263-1269
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• 2016

Hearing impaired persons are exposed to the danger since they can't be aware of many dangerous situations like fire alarms, car hones and so on. Therefore they need haptic or visual informations when they meet dangerous situations. In this paper, we design a dangerous sound detection engine for hearing impaired. We consider four dangerous indoor situations such as a boiled sound of kettle, a fire alarm, a door bell and a phone ringing. For outdoor, two dangerous situations such as a car horn and a siren of emergency vehicle are considered. For a test, 6 data sets are collected from those six situations. we extract LPC, LPCC and MFCC as feature vectors from the collected data and compare the vectors for feasibility. Finally we design a matching engine using an artificial neural network and perform classification tests. We perform classification tests for 3 times considering the use outdoors and indoors. The test result shows the feasibility for the dangerous sound detection.