• Survey Research
• /
• v.11 no.2
• /
• pp.29-44
• /
• 2010

The aim of this study was to determine principal non-acoustical factors for noise annoyance in the vicinity of Kimpo Airport in Seoul, Korea. Noise annoyance was estimated using self-reported annoyance scale. We have conducted a social survey aiming to identify the main sound sources, evaluate the annoyance and analyse the main effects of noise on people. Acoustical and non-acoustical variables are expected to greatly affect annoyance responses. This study divided acoustical variables into aircraft, road traffic and neighboring noises, and non-acoustical variables into demographic, situational and attitudinal variables. The study performed multiple regression analysis to determine the influences each variable has on annoyance responses. Acoustical variables affect noise annoyance to aircraft and neighboring noise except road traffic noise. For road traffic and neighboring noise annoyance was affected by non-acoustical variable, insulation by housing type. For aircraft noise, main noise source of this area, annoyance was affected by acoustical variable and some non-acoustical variables, mainly exposure time.

• Phonetics and Speech Sciences
• /
• v.12 no.3
• /
• pp.73-83
• /
• 2020

Measured values may differ between Multi-Dimensional Voice Program (MDVP), Praat, and Time-Frequency Analysis software (TF32), all of which are widely used in voice quality analysis, due to differences in the algorithms used in each analyzer. Therefore, this study aimed to compare the values of parameters of normal voice measured with each analyzer. After tokens of the vowel sound /a/ were collected from 35 normal adult subjects (19 male and 16 female), they were analyzed with MDVP, Praat, and TF32. The mean values obtained from Praat for jitter variables (J local, J abs, J rap, and J ppq), shimmer variables (S local, S dB, and S apq), and noise-to-harmonics ratio (NHR) were significantly lower than those from MDVP in both males and females (p<.01). The mean values of J local, J abs, and S local were significantly lower in the order MDVP, Praat, and TF32 in both genders. In conclusion, the measured values differed across voice analyzers due to the differences in the algorithms each analyzer uses. Therefore, it is important for clinicians to analyze pathologic voice after understanding the normal criteria used by each analyzer when they use a voice analyzer in clinical practice.

• Geophysics and Geophysical Exploration
• /
• v.2 no.4
• /
• pp.202-208
• /
• 1999

We introduce a new acoustic parameter for the classification of seafloor sediments from chirp sonar acoustic profiling data. The acoustic parameter is defined as a derivative of the unwrapped phase of the Fourier transform of acoustic profiling data. Consequently, it represents the characteristics of attenuation by dissipative dispersion in sediments. And we estimated acoustic properties by geoacoustic modeling using Chirp data obtained from the different sedimentary facies. Our classification results, when compared with the results of analysis of sampled sediments, show that the acoustic parameter discriminates sedimentary facies and bottom hardness. Thus the method in this paper is expected to be an effective means of geoacoustic modeling of the seafloor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2003.10a
• /
• pp.153-156
• /
• 2003

Backhole, which is one of geometric parameters in swirl coaxial injectors, is found to affect the inner flow motion and the acoustic characteristics of the swirl injector. In order to analyze the effect of the backhole as a damping device such as acoustic cavities of the combustion chamber, it was regarded as a Helmholtz or Quarter-wave resonator. As a result, it is known that the swirl coaxial injector with the backhole may produce the resonant frequency coincided with the frequency of the combustion chamber.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.7
• /
• pp.3048-3056
• /
• 2012

The purpose of this study was to investigate VHI, V-RQOL, and vocal characteristics of a teacher and singer. 56 subjects were participated in this study (20 subjects are a teacher with vocal nodule, 20 subjects are a singer with vocal nodule, and 16 subjects are normal speakers). All subjects completed the VHI, V-RQOL, and vocal characteristics were measured using CSL 4500(Kay Pentax. USA). 21 subjects completed the VHI, V-RQOL, and vocal evaluation using CSL 4500 twice to assess test-retest reliability. A statistical analysis was performed using the Statistical Package for Social Sciences 18.0 (SPSS Inc, Chicago, IL). The VHI and V-RQOL showed that the teacher and singer group were significantly higher than those of the control group in functional, physical and emotional aspects(p<0.05). the acoustic analysis using CSL 4500 showed the teacher and singer group were significantly higher than those of the the control group in fundamental frequency related variables, fundamental perturbation related variables, amplitude perturbation related variables, noise related variable, and tremor related variables(p<0.05). Conclusionally, the teacher and singer group recognized their voice problems as a serious physico-functional aspects.

• Science of Emotion and Sensibility
• /
• v.15 no.2
• /
• pp.201-208
• /
• 2012

The objectives of this study were to investigate the psychoacoustic properties of PTFE(Poly tetra Fluoroethylene) laminated vapor permeable water repellent fabrics which are frequently used for sportswear, to examine the relationship among fabrics' basic characteristics, mechanical properties and the psychoacoustic properties, and finally to propose the predicting model to minimize the psychoacoustic fabric sound. A total of 8 specimens' frictional sound were recorded and Zwicker's psychoacoustic parameters such as loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z) were calculated using the Sound Quality Program. Mechanical properties of specimens were measured by KES-FB system. Loudness(Z) of specimen D-1 was the highest, which means the rustling sound of the specimen D-1 was the most noisy. Statistically significant difference among film type was observed only in loudness(Z) for fabric sound. Based on ANOVA and post-hoc test, specimens were classified into less loud PTFE film group (groupI) and loud PTFE film group (groupII). Loudness(Z) was higher when staple yarn was used compared when filament yarn was used. According to the correlation between the mechanical properties of fabrics and loudness(Z) in groupI, the shear properties, compression properties and weight showed positive correlation with loudness(Z). According to the regression equation predicting loudness(Z) of groupI, the layer variable was chosen. In groupII, variables explaining the loudness(Z) were yarn types and shear hysteresis(2HG5).

• Proceedings of the KSLP Conference
• /
• 2003.11a
• /
• pp.240-240
• /
• 2003

본 논문에서는 기존의 매개변수들과 달리 화자의 고유한 특성을 보여주는 화자인식 매개변수를 발성유형에서 찾고자 한다. 일반적으로 화자의 음원 특성이 발성 유형을 결정한다. 발성유형의 특성을 나타내는 매개변수로는 개방지수(open quotient)와 스펙트럼의 기울기 (spectral tilt)가 있으며, 스펙트럼의 기울기는 음향학적으로 그 특성을 측정할 수 있다. 그러나 기존의 측정방식은 사람마다 다른 기본 주파수와 모음의 영향을 전부 혹은 일부 배제하지 못하였다. (중략)

• Journal of the korean Society of Automotive Engineers
• /
• v.17 no.1
• /
• pp.20-30
• /
• 1995

제1부에서는 소음기를 구성하는 각종 기본요소의 구조에 따른 음향성능의 특성을 간략히 살펴보았고, 제2부에서는 소음기의 음향특성을 해석할 때 쓰이는 각종 성능지수의 정의와 계산상 처리방법에 관하여 토론을 하였다. 본 3부에서는 선형음향해석시에 관련된 각 요소당 관련변수에 대해 알아보고, 소음계 설계에 있어서 기본적으로 염두에 두어야 할 사항들에 대해 논의하고자 한다. 최근에는 컴퓨터 원용설계가 일반적으로 적극 수용되고 있으며 여기서는 이를 이해하기 위한 음향해석의 기본원리를 토론하고, 개념설계시에 사용되는 기본요소들의 기초적 특성에 대하여 언급하고자 한다. 1. 선형 음향해석. 1.1 일반적 가정. 1.2 선형모델에 포함된 소음계 요소의 기하학적 변수. 1.3 각 소음계 요소의 전달 매트릭스. 2. 가장 기초적인 일반 설계 지침.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.399-402
• /
• 2009

Acoustic design parameters of a Helmholtz resonator are studied experimentally and numerically for acoustic stability in a model acoustic tube. According to standard acoustic-test procedures, acoustic-pressure signals are measured. Quantitative acoustic properties of sound absorption coefficient are evaluated and thereby, the acoustic damping capacity of the resonator is characterized. Helmholtz resonator on spring-damper system use were understanding for acoustic damping. The length of orifice and the volume of cavity of resonator are selected as design parameters for tuning of the resonator. Acoustic- damping capacity of the resonator increases with its cavity volume. And orifice length as increases with acoustic damping capacity was decreased.

• Journal of KSNVE
• /
• v.6 no.5
• /
• pp.661-669
• /
• 1996

Proposed is an aero-acoustic performance prediction method of axial fan. The fan aerodynamic performance is predicted by combining pitch-averaged quasi 3-D flow analysis with pressure loss models for blade boundary layer and wake, secondary flow, endwall boundary layer and tip leakage flows. Fan noise is assumed to be radiated as dipole distribution type, and its generation is assumed to be mainly due to the vortex street shed from blade trailing edge. The fluctuating pressure and lift on the blade surface are analyzed by incorporating the wake vortex stree shed from blade trailing edge. The fluctuating pressure and lift on the blade surface are analyzed by incorporating the wake vortex street model with thin airfoil theory. The aero-acoustic performance prediction results by the present method are in good agreement with the measured results of several axial fans. With the present prediction method, parametric studies are carried out to investigate the effects of blade chord length and spacing on the efficiency and the noise level of fan. In the case of lightly loaded fan, both efficiency improvement and noise reduction can be achieved by decreasing chord length or by increasing blade specing. However, when fan is designed at highly loaded condition, the noise reduction by increasing blade spacing penalizes the attaninable efficiency of fan.