• Fire Science and Engineering
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• v.33 no.1
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• pp.130-137
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• 2019

In this study, the acoustic characteristics of 13 types of emergency broadcasting speakers were tested under the test set-up of UL 2043 and compared. When the sound pressure level of 1 W speakers was compared with speakers with a 15 W output, the SPL of the 15 W speakers was approximately 20 dB higher in some frequency bands. Loudness analysis showed that people can recognize emergency sound from a 15 W speaker twice as loud as the emergency sound from 1 W speakers. The analysis results on the articulation index (room) had an opposite tendency with loudness results, meaning that small speakers can generate clearer sound. Therefore, it is necessary to improve emergency broadcasting speakers to generate louder and clearer sound. Moreover, a performance evaluation standard is needed based on the reasonable and quantitative measurements and evaluations of the acoustic characteristics of the emergency-broadcasting speakers so that a sufficient and clear sound can be generated in various spaces. In addition, it is necessary to establish standards for the clarity of emergency broadcasting in various spaces.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.47-52
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• 1996

Interior noise, engine speed and vehicle speed are measured under road-load condition and interior noise signal is transformed by using the transient signal analysis methods such as the spectrogram and wavelet transform. Using the analyzed results, subjective noise criteria such as the loudness, noisiness and articulation index at each vehicle speed can be estimated and characteristics of interior noise for various running mode can be discussed in the viewpoint of noise quality.

• The Journal of the Acoustical Society of Korea
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• v.4 no.1
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• pp.43-54
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• 1985

이 논문에서는 Frequency weighting을 이용하여 선형예측 부호화기의 명료성을 개선하는 방법 을 연구한다. 잡음이 섞이지 않은 음성에 대해서는 음성을 분석하기전에 frequency weighting을 행한다. 또한 잡음이 섞인 음성인 경우에는 잡음성분을 spectral subtraction 방법에 의해서 제거한 다음에 frequency weighting을 준다. 이 때 frequency weighting을 주기 위해서 귀의 특성과 연관되어 잘 알려 진 C- message weighting 함수, flanagan weighting 함수 및 articulation index를 약간 수정한 weighting 함수를 사용했다. 여러 객관적인 distance measure를 사용하여 frequency weighting 방법의 성능을 측정하고 귀로 들어 본 결과, frequency weighting 방법을 사용하여 선형예측 방법에 의한 합성 음의 명료도를 효율적으로 개선할 수 있었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2930-2936
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• 2014

The purposes of this study were to investigate the characteristics of speech rate and pause in patients with flaccid dysarthria. For this purpose, 15 patients with flaccid dysarthria and 15 normal speakers matched in gender and age participated as subjects. The overall speech rate, the articulation rate, the inter-sentence and the intra-sentence pause duration and pause frequency were measured during reading the standardized passage "Autumn"(Kim, 1996). As a result, the overall speech rate and articulation rate of patients with flaccid dysarthria were significantly slower than normal speakers and intra-sentence pause duration and frequency of patients with flaccid dysarthria were significantly higher than normal speakers, but those of inter-sentence weren't. The results from this study provides the speech rate index of flaccid dysarthria and indicates that to control the speech rate of flaccid dysarthria have regard to not only the overall speech rate and the articulation rate but also the intra-sentence pause duration and the frequency.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.1
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• pp.32-38
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• 2007

In order to establish the environmental condition of sounds in the classroom, we measured the impulse response in cases of using and not-using PA(Public-Address). By calculating the physical index of acoustics, I examined the differences between the two cases. The degree of improvement in listening with the help of PA has also been studied by testing the voice articulation with the use of the measured impulse response. As a result, I found that the clearness is enhanced by increasing the sound pressure level in the case of short reverberation. However, it was not the case when the reverberation time was long.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.440-443
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• 2005

The wide spread of internet business recently necessitates recommendation systems which can recommend the most suitable product fur customer demands. Currently the recommendation systems use content-based filtering and/or collaborative filtering methods, which are unable both to explain the reason for the recommendation and to reflect constantly changing requirements of the users. These methods guarantee good efficiency only if there is a lot of information about users. This paper proposes an algorithm called 'demand articulate & integration' which can perceive user's continuously varying intents and recommend proper contents. A method of knowledge classification which can be applicable to this algorithm is also developed in order to disassemble knowledge into basic units and articulate indices. The algorithm provides recommendation outputs that are close to expert's opinion through the tracing of articulate index. As a case study, a knowledge base for heritage information is constructed with the expert guide's knowledge. An intelligent recommendation system that can guide heritage tour as good as the expert guider is developed.

• Journal of Oral Medicine and Pain
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• v.11 no.1
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• pp.57-66
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• 1986

A study of occlusal relationship and TMJ dysfunction, parafunctional relationship and TMJ dysfunction using PRI was investigated in 23 dental students without history of being treated, ranging from 19 to 24 years old. The author used Denar Pantronic and D5-A articulator to study above. The obtained results were as follows : 1. Distribution of PRI in experimental subjects was as follows. None 13%, Slight 43%, Moderate 40%, Severe 4% Prevalance of TMJ Dysfunction was 87% 2. PRI scores of occlusal group Aoi (less than 5 in Helkimo occlusion/articulation index) was $11.72\pm2.32$ , those of occlusal group Boi (more than 5 in Helkimo occlusion/articulation index) 23.0 $\pm$ 8.06. There was a significant difference between group Aoi and group Boi(P<0.01) 3. PRI scores of occlusal group Ald (no eccentric interference, less than 0.5mm in lateral shift of slide in centric) was 12.0 $\pm$ 2.49, those of occlusal group Bld(no eccentric interference, less than 0.5mm in lateral shift of slide in centric) 24.5$\pm$5.33 There was a significant difference between group Ald and group Bld(P<0.05) 4. Prevalance of parafunction subjects(%) was 65.2%. 5. PRI scores of parafunction group was 21.6 $\pm$ 9.48, those of nonparafunctional group 18.7 $\pm$ 9.06. There was not significant difference between parafunctional group and nonparafunctional group(P>0.1)

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.5
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• pp.615-622
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• 2012

Airborne radio communications, navigation, and identification equipments are the basic equipment of airplane. Airborne radio communications, navigation, and identification equipments are characterized by user's many quantitative and qualitative requirements. These equipment look like simple test and evaluation, but they have many complex factors. This paper describe the test and evaluation of airborne radio communications, navigation, and identification equipments.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.6
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• pp.509-523
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• 2012

The sound quality based on design optimization, throughout the development process of various electronic office equipments, needs to be considered in order to respond the increased needs for the emotional satisfaction of customers in terms of psycho-acoustics. This paper focuses on how to describe the characteristics of operating sound radiated from laser printers by using various sound attributes, and to model the sound quality index that can properly evaluate the subjective preference on modification conditions in the improvement study quantitatively. Especially, the proposed verification process, in the form of combining the correlation based method and the decision error based method, was applied to improve the generality and reliability of a group of participants in the jury evaluation. The modified Aures tonality model was also proposed to improve the correlation coefficient with the mean response of participants by optimizing some parameters. As a result, the loudness, articulation index, roughness, tonality, fluctuation strength were used to model the sound quality index for laser printers by using the multiple-linear regression method. Through the improvement study, it was confirmed that replacing the absorbing materials is effective to reduce the tonalness radiated from the side of a reference printer model. Based on above results, it can be concluded that the proposed model has enough usefulness as quantitative evaluation index to evaluate the difference between modification conditions in the improvement study.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.10
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• pp.883-889
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• 2011

The brand sound of vehicle diesel engine is recently one of the important advantage strategies in the automotive company. Because various noise components masked under high frequency level can be audible in quieter driving situation. Many researches have been carried out for subjective and objective assessments on vehicle sounds and noises. In particular, the interior sound quality has been one of research fields that can give high quality feature to vehicle products. Vehicle interior noise above 500 Hz is usually controlled by sound package parts. The materials and geometries of sound package parts directly affect on this high frequency noise. This paper describes the sound quality evaluation method for the vehicle diesel engine noise to establish objective criteria for sound quality assessment. Considering the sensitivity of human hearing to impulsive sounds such as diesel noise, the human auditory mechanism was simulated by introducing temporal masking in the time domain. Furthermore, each of the human auditory organs was simulated by computer codes, providing reasonable analytical explanations of typical human hearing responses to diesel noise. This method finally provides the sound quality index of vehicle diesel engine noise that includes high frequency intermittent offensive sounds caused by impacting excitations of combustion and piston slap.