• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.975-978
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• 2007

This paper investigates stage acoustics in concert halls for ensemble performance in terms of stage support parameters. A concert hall with large stage area was selected. Objective measurements were carried out according to Gade's methods for investigating stage support (ST1). The sound field on the stage was evaluated using stage and audience acoustical parameters. According to the positions at stage, different acoustical characteristics were found. Higher ST1 and lower $IACC_{E3}$ were measured near side and rear stage walls. In case of conductor/soloist vs. orchestra player, objective measurement of acoustical parameters shows that early sound fields depend on the source-receiver distance but late sound fields depend on the location of side and rear walls. In addition, in-situ evaluation of the trio instrumentalists was carried out. Results show that ensemble is favored by higher early reflection of sounds and sound diffusion affecting ‘blending’ of their performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2629-2650
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• 2019

It is important to construct fully homomorphic encryption with ciphertext matrix that makes fully homomorphic encryption become very nature and simple. We present a general design method of constructing fully homomorphic encryption whose ciphertext is matrix. By using this design method, we can deduce a fully homomorphic encryption scheme step by step based on a basic encryption scheme. The process of deduction is similar to solving equation and the final output result is a fully homomorphic encryption scheme with ciphertext matrix. The idea of constructing ciphertext matrix is ciphertexts stack, which don't simply stack ciphertexts together but is to obtain the desired homomorphic property. We use decryption structure as tool to analyze homomorphic property and noise growth during homomorphic evaluation. By using this design method, we obtain three corresponding fully homomorphic encryption schemes. Our obtained fully homomorphic encryption schemes are more efficient. Finally, we introduce the adversary advantage and improve the previous method of estimating concert parameters of fully homomorphic encryption. We give the concert parameters of these schemes.

• The Journal of the Acoustical Society of Korea
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• v.24 no.2
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• pp.111-116
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• 2005

This study deals with a subjective assessment to investigate the preferred acoustic conditions and determine the important acoustical parameters in concert halls. A subjective test was carried out using dummy head recorded sounds made in actual halls in Australia (referred to as Hall A and Hall B) to evaluate the acoustic performance of two halls. The results of subjective tests were then correlated with measured acoustical parameters to investigate the significant determinants for the preference judgements. The listeners show a stronger Preference for seats in the Hall B than those in the Hall A. The low preferences for seats in the Hall A are in agreement with live performance ratings assessed by musicians. It is found that the sound level is the most significant acoustical parameter for evaluating the overall acoustic preference in the two halls.

• The Journal of the Acoustical Society of Korea
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• v.38 no.2
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• pp.139-144
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• 2019

Various room acoustic parameters and their optimal values were proposed and verified as proper interpretations to the listeners' preference of concert hall sounds. However the listening environment has been changed since they were developed, and the listeners' preference may not be the same among countries of different cultural backgrounds. Actual listeners' preference should be applied to the design of a new concert hall. A survey on the listening preference was carried out for 22 music experts. A room acoustical design process was proposed which made the acoustical environment of a concert hall as close to the listeners' preferences.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.987-990
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• 2007

The accuracy of sound strength (G) measurement method in ISO 3382 has been questioned. One of the main reason is the difficulty in measuring a reference sound level in an anechoic chamber with the same set-up which was applied for the actual hall measurements. In the present paper, an in-situ measurement method for G was proposed by investigating the present G measurement method shown in ISO 3382. In addition, the sound radiation characteristics of typical omnidirectional loudspeakers were investigated and Phi (O) of auto correlation function (ACF) parameters was also calculated from an actual music excerpt to characterize the sound energy distribution in concert halls.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.979-982
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• 2007

The effect of a scattering wall surfaces on sound diffusion can be assessed by determining the scattering and diffusion coefficients in the laboratory. However, the sound field in a concert hall including scattered reflections is different from the laboratory measurement condition. Therefore, there is a need for objective investigation of diffusion in real sound fields. In this paper, possible acoustical parameters of in-situ measurements are discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.87-91
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• 2005

The effects of the movable reflectors on the stage acoustics in Seoul's Sejong Performing Arts Center (3,048-seat multi-purpose hall, stage area of $270m^2$ within an orchestra shell) and Ceramic Palace Hall (440-seat concert hall, stage area of $105m^2$) were investigated. Acoustical parameters were evaluated by measuring stage and audience acoustics in the two halls. The study was primarily based on the stage support parameter STI proposed by Gade (Acustica 65, pp.193-203, 1989). Results showed that STI varied on the stage of the large hall according to the position of the reflectors, whereas STI did not vary in the small hall. In the large hall, a smaller clear stage area (bounded by the reflectors) yields an increase in both STI and other early energy measures. In the small hall, early energy decreases when its stage's surface diffusion was covered with specular reflectors.

• The Journal of the Acoustical Society of Korea
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• v.19 no.1
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• pp.48-53
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• 2000

To analyze a room reverberation, many objective parameters have been suggested as measures of subjective perception in concert hall acoustics. However, it is difficult to understand the relationship among the individual parameters and to have a whole image of them. In this paper five primary objective parameters were selected and a reverberation model based on them was established by the reverberation decay curve. The proposed model was interpreted geometrically in terms of subjective characteristics. And finally we discuss the usefulness and the limitation of the model when it is applied to the analysis and.

• The Journal of the Acoustical Society of Korea
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• v.42 no.3
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• pp.189-202
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• 2023

In this study, the acoustic performance was analyzed by architectural shapes of the hall. There are four architectural shapes of halls. They are rectangular, horseshoe, surround, and fan-shape. Eight acoustic parameters were used to determine the acoustic performance. These are RT₆₀, EDT, C₈₀, BQI, LF, G_mid, G₁₂₅ and ITDG. First, measurement data of famous concert halls around the world were analyzed. The correlation coefficient R was obtained by regression analysis of the relationship between the subjective ranking of the halls and the acoustic parameters. It was found that BQI, G, and ITDG have higher correlation coefficients R. Also the average of acoustic parameters for each architectural shape were obtained. The total acoustic performance for each shape was calculated by using the correlation coefficient R as a weight for each acoustic parameters. As a result, rectangular halls and horseshoe halls showed good acoustical performances. Second, 3D models of each architectural shape were created and acoustic simulation had been performed. The simulation was performed by creating 3D models of each four shapes of concert halls with the same volume and sound absorption coefficient. Listening test was carried out using the sound source which is created from impulse responses of 3D model. As a result, rectangular hall and horseshoe hall showed the best performance however surround hall and fan-shaped hall showed relatively poor performance.

• The Journal of the Acoustical Society of Korea
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• v.27 no.6
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• pp.296-302
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• 2008

This study investigated that the preference model of soloist performers for both vocal and instrumental types in terms of a stage support parameter, ST1. The test was carried out on a stage of a fan-shaped multi-purpose hall with orchestra shell. Objective measurements were carried out at 15 positions on the stage to evaluate various stage condition. The results showed that ST1 varies between -19.9 and -11.3 dB. Vocal and instrumental players participated in performance evaluation test as they played at 5 selected positions according to ST1 values. Players' preference was evaluated by 5-point rating and rank ordering method. As a result, it was found that the preference model of vocalist is different from that of instrumentalist. It was also found that the ST1 does not correlate well with the performer's preference.