• ETRI Journal
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• 제27권5호
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• pp.635-638
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• 2005

Spatial audio coding (SAC) is an extremely high compact representation of encoded multi-channel audio material. This paper suggests a multi-channel audio service in the terrestrial digital multimedia broadcasting (T-DMB) system using a novel SAC tool, which is called a virtual source location information (VSLI)-based SAC tool. Intensive experiments are presented to evaluate the validity of the proposed VSLI-based SAC tool, and prototypical systems are also presented to demonstrate the reliability of the proposed multi-channel T-DMB system in real applications.

• 한국주거학회논문집
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• 제19권4호
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• pp.49-57
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• 2008

The case study for this research is a middle school music room located in Iksan City, Korea. Although the room is used for teaching music, indiscreet sound-absorbing materials were applied within the space. Accordingly, a number of difficulties have been experienced when using the room. During a music lesson, the sound-volume is inadequate for music appreciation, while the music performance has an arid sound due to an insufficient echo. In order to control the obstructive factors resulting from a short Reverberation Time, the acoustic factor is optimized in this study by using an Acoustic Simulation, following an arrangement of Acoustic Design. A Psycho-acoustics Experiment was conducted using the Auralizational Technique, whereby the Virtual Acoustic Field can be experienced at the design stage.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(4)
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• pp.135-138
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• 2001

Many researchers have developed the techniques of an efficient 3-D sound system based on the psycho-acoustics of spatial hearing with multimedia or virtual reality In this paper, we propose an idea for the improved 3-D sound system using conventional stereo headphones to obtain a better sound diffusion from the mono-sound recorded at an anechoic chamber. We use the HRTF (Head Related Transfer Function) for the sound localization and the wavelet filter bank with time delay for the sound diffusion. We investigate the effects of the 3-B sound depending on the length of time delay at lowest frequency band. Also the correlation coefficient of the signals between the left channel and the right channel is measured to identify the sound diffusion.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2011년도 정기 학술대회
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• pp.295-298
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• 2011

최근 3년간 판 구조물의 손상진단에서 시간반전램파 (Time reversal Lamb waves)의 가능성이 주목 받고 있다. 시간반전음향학(Time reversal acoustics)에 의하면 시간반전램파의 공간모임을 적절히 활용하면 판에 순간적으로 가해지거나 발생한 충격하중의 위치를 높은 공간해상도와 신호대 잡음비로 추정할 수 있다고 알려져 있다. 이 연구에서는 시간반전램파의 공간모임을 직사각형 평판에서 가상탐지자 모델을 이용하여 모사한다. 특히, 평판에서의 파 반사에 의해 발생하는 가상탐지자 효과에 의해 단일 부착형 압전소자만을 사용하더라도 시간반전 램파의 공간 모임 구현이 가능함을 보인다. 또한 제안된 방법의 결과를 유한 요소 해석결과와 비교하고 제안된 방법의 타당성을 보인다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송∙미디어공학회 2022년도 추계학술대회
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• pp.26-29
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• 2022

The diffuse sound field plays a crucial role in the perceptual quality of the auralization of virtual scenes. Diffuse Rain is a geometrical scattering model which enables the simulation of diffuse fields that is compatible with acoustic ray tracing, but is often computationally expensive. We develop a novel method that can reduce this cost by rendering the large number of Diffuse Rain data in Ambisonics format. The proposed method is evaluated in a shoebox scene simulation run on MATLAB, in reference to a more faithful method of rendering the Diffuse Rain data ray-by-ray. The EDC and IACC of the binaural output show that the simulated diffuse field can be rendered in Ambisonics with only minimal deviations in energy decay and spatial quality, even with 1^st-order Ambisonics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.48-48
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• 2010

Sound quality and NVH-issues(Noise, Vibration and Harshness) of vehicles has become very important for car manufacturers. It is interpreted as among the most relevant factors regarding perceived product quality, and is important in gaining market advantage. The general sound quality of vehicles was gradually improved over the years. However, today the development cycles in the automotive industry are constantly reduced to meet the customers' demands and to react quickly to market needs. In addition, new drive and fuel concepts, tightened ecological specifications, increase of vehicle classes and increasing diversification(increasing market for niche vehicles), etc. challenge the acoustic engineers trying to develop a pleasant, adequate, harmonious passenger cabin sound. Another aspect concerns the general pressure for reducing emission and fuel consumption, which lead to vehicle weight reductions through material changes also resulting in new noise and vibration conflicts. Furthermore, in the context of alternative powertrains and engine concepts, the new objective is to detect and implement the vehicle sound, tailored to suit the auditory expectations and needs of the target group. New questions must be answered: What are appropriate sounds for hybrid or electric vehicles? How are new vehicle sounds perceived and judged? How can customer-oriented, client-specific target sounds be determined? Which sounds are needed to fulfil the driving task, and so on? Thus, advanced methods and tools are necessary which cope with the increasing complexity of NVH-problems and conflicts and at the same time which cope with the growing expectations regarding the acoustical comfort. Moreover, it is exceedingly important to have already detailed and reliable information about NVH-issues in early design phases to guarantee high quality standards. This requires the use of sophisticated simulation techniques, which allow for the virtual construction and testing of subsystems and/or the whole car in early development stages. The virtual, testing is very important especially with respect to alternative drive concepts(hybrid cars, electric cars, hydrogen fuel cell cars), where complete new NVH-problems and challenges occur which have to be adequately managed right from the beginning. In this context, it is important to mention that the challenge is that all noise contributions from different sources lead to a harmonious, well-balanced overall sound. The optimization of single sources alone does not automatically result in an ideal overall vehicle sound. The paper highlights modern and innovative NVH measurement technologies as well as presents solutions of recent NVH tasks and challenges. Furthermore, future prospects and developments in the field of automotive acoustics are considered and discussed.

• 한국엔터테인먼트산업학회논문지
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• 제14권7호
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• pp.299-307
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• 2020

1964년부터 국악기의 현대화, 표준화, 과학화 등을 위해 국악기에 대한 연구와 개량사업이 추진되었으나, 국악기가 가지고 있는 고질적인 문제들은 큰 성과를 거두지 못하였다. 이러한 주요 원인중 하나는 국악기에 대한 악기 음향학 연구가 선행되지 못한 것으로 분석되고 있다. 국악기 중 협주곡이나 독주곡에서 사용하고 있는 소금은 맑은 음색과 높은 음역으로 인하여 국악관현악단에서도 서양 오케스트라에서의 플룻의 역할을 수행하고 있는 악기이다. 본 논문에서는 비슷한 음색으로 들리는 소금과 플룻의 음색을 악기가 가지고 있는 배음의 분포와 구조를 통해 분석하였다. 이를 통해 전체적인 음색은 소금에 비하여 플룻이 풍부하고 부드럽다는 것을 알 수 있었고, 고음으로 갈수록 배음들의 비슷한 구성으로 인하여 두 악기의 음색이 비슷하게 들린다는 것을 알 수 있었다. 추후에는 다양한 국악기들에 대한 악기 음향학적 연구가 지속적으로 수행되어 국악기의 대중화와 세계화에 작게나마 도움이 되길 기대한다.

• Advances in aircraft and spacecraft science
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• 제5권2호
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• pp.205-223
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• 2018

During launch a spacecraft is subjected to a variety of dynamical loads transmitted through the launcher to spacecraft interface or air-born transmission excitations in the acoustic pressure field inside the fairing. As a result, spacecraft are tested on ground to ensure and demonstrate the global integrity of the structure against these loads, to screen the flight hardware for quality of workmanship and to validate mathematical models. This paper addresses the numerical modelling and simulation of the low frequency sine and random vibration tests performed on electrodynamic shaker facilities to comprise the mechanical-borne transmission loads through the launcher to spacecraft interface. Consequently, the paper reviews techniques and methodologies to derive a reliable and representative coupled virtual vibration testing simulation environment based on experimental data. These technologies are explored with the main objectives to ensure a stable, reliable and accurate control while testing. As a result, the use of the derived simulation models in combination with the added value of improved control and signal processing algorithms can lead to a safer and smoother vibration test control of the entire environmental test campaign.

• 한국소음진동공학회논문집
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• 제17권8호
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• pp.708-719
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• 2007

In case of indoor gymnastics training floor, in view of its characteristics, since it is simultaneously required the related smooth communication between the coach and the player, also the acoustic performance regarding to the clearness of music, besides the sport activity, the consideration about the acoustic character has entered the stage as an indispensable element. On such viewpoint, recently constructed dome-typed gymnastic training floor was optimized acoustic design with remodeling through acoustic simulation test. And acoustic satisfaction degree and reaction was attempted to investigate about the gymnastics training floor estimating value of human's psychological(sensual) degree using auralization that enables to experience the virtual sound field at the stage of design. As the result of investigation about the research on the space of object, it could be known that the valuation regarding to the acoustic performance of 'after-improvement' was distinctly more refined than that of 'before-improvement'. It is now considering that such result of the study can be utilized as the useful data which enables to improve the retrenchment effect of the construction cost as well as the acoustic capability, by means of the prediction control on the acoustic problem from the stage of design, for the occasion when the similar indoor sport gymnasium is planning to build for the near future.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2008년도 춘계학술발표대회 논문집
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• pp.272-275
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• 2008

In case a middle school music room locating in Iksan City, this space had been finished its construction work with the indiscreet sound-absorbing materials despite the music lesson is taught thereat. Accordingly, when music lesson since it sounds aridly due to insufficiency of echo and sound-volume feeling in music appreciation or music performance sound, there is some difficulty in the music lesson. For the purpose to control the obstructive factors owing to such short Reverberation Time, it optimizes the acoustic factor using Acoustic Simulation after arrangement of Acoustic Design, it has conducted a Psycho-acoustics Experiment using the Auralizational Technique that can experience the Virtual Acoustic Field at its designing stage. As the result of investigation about the acoustic satisfaction on the relevant subject space and the satisfaction with regard to the pertinent each items, it was known that the valuation on acoustic performance was evidently improved at 'after-reformation' than 'before-reformation'. It is considered that such material could be utilized as the useful material that can improve the architectural acoustic factor when construction and renovation of any middle school music room in the future.