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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society for Noise and Vibration Engineering
Journal Basic Information
Journal DOI :
The Korean Society for Noise and Vibration Engineering
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Volume & Issues
Volume 18, Issue 12 - Dec 2008
Volume 18, Issue 11 - Nov 2008
Volume 18, Issue 10 - Oct 2008
Volume 18, Issue 9 - Sep 2008
Volume 18, Issue 8 - Aug 2008
Volume 18, Issue 7 - Jul 2008
Volume 18, Issue 6 - Jun 2008
Volume 18, Issue 5 - May 2008
Volume 18, Issue 4 - Apr 2008
Volume 18, Issue 3 - Mar 2008
Volume 18, Issue 2 - Feb 2008
Volume 18, Issue 1 - Jan 2008
Selecting the target year
Seismic Performance Enhancement of Building Structures with Beam-end Rotation Type Dampers
Woo, Sung-Sik ; Lee, Sang-Hyun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 589~597
DOI : 10.5050/KSNVN.2008.18.6.589
The vertical extension of a building in general remodeling process increases both gravity and seismic loads by simply adding masses to the building. In this study, a vertical extension structural module(VESM) is proposed for enhancing seismic performance of the existing buildings by utilizing the story-increased parts. The proposed VESM is composed of steel column, steel beam, and beam-end rotational damper. The steel columns are connected to the shear walls and transfer the wall rotation in out-of plane to the steel beam, and then the beam-end rotational damper dissipates the earthquake-induced energy. Numerical analysis result from a cantilever beam of which end-rotation is restricted by rotational damper indicates that the displacement, base shear, and base overturning moment of the existing structures showing cantilever behavior can be significantly reduced by using the proposed method. Also, it is observed that friction-type rotational damper is effective than viscous one.
Measurement of Normal Incidence Surface Impedance of Absorbing Materials Using the Improved Beamforming Method in a Free Field
Shin, Chang-Woo ; Sun, Jong-Choen ; Kang, Yeon-June ; Paik, Soon-Kwon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 598~605
DOI : 10.5050/KSNVN.2008.18.6.598
An improved beamforming method is proposed to measure the surface impedance of absorbing materials in a free field. It is possible to estimate the surface impedance by decomposing measured signals into incident and reflected signals by using the spatial filter matrix of the beamforming method. Wavelet do-noising techniques which reduce the white Gaussian noise are applied to improve the results. Phase calibration method is also used to improve the results of the measured surface impedance in a low frequency range. The results of the normal incidence experiments that are performed in a semi-anechoic chamber are verified by comparing with those of the standard test method that is presented in ASTM E1050. The proposed method is found to be reliable to measure the surface impedance for frequencies higher than 400 Hz.
Qualitative Noise Characteristics of Rotating Polygonal Disk Applied to Digital Printer Systems
Jo, Jun-Hyeon ; Kim, Hyeong-Chae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 606~611
DOI : 10.5050/KSNVN.2008.18.6.606
Consumer`s product selection measures are being shifted from the units` operational performance to overall performance. Low noise, low vibration, and low power consumption rate, etc. which used to be additional quality indices, now become vital performance factors. Especially, noise and vibration characteristics are being considered as equivalent to/or even more critical than operational performance in certain products such as office machines and home entertainment systems, which share the same space with human being`s daily life. Therefore, noise reduction and sound quality improvement technology becomes an inevitable design issue for those applications. Qualitative noise characteristics of rotating polygonal disk applied to digital printer systems are presented. Overall sound pressure level change and tonal noise variation with respect to the geometrical properties of polygonal disk, operational speed, and others are briefly discussed based on experimental results.
Study on Shear Layer Correction of Microphone Array Measurement in the Wind Tunnel Test
Kim, Wi-Jun ; Rhee, Wook ; Choi, Jong-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 612~618
DOI : 10.5050/KSNVN.2008.18.6.612
Microphone array beamforming method has been recognized as an important aeroacoustic research field and become a standard technique in localizing sound sources. This method also used in flight acoustic measurement, and especially, it is very useful when measure sounds inside the wind tunnel. In measuring sound which is inside the wind tunnel by traditional beamforming method, there are some errors caused by airstream. The speed and the propagation path of the sound changes as it travel through the airstream. This makes the error which the position of sound is changed a little bit to the down stream direction. In this paper, validation test has made about the correction equation for this wind effects of previous researches. And beamforming including shear layer correction was performed about a sound source in the anechoic open-jet wind tunnel.
A Fault Diagnosis on the Rotating Machinery Using MTS
Park, Sang-Gil ; Park, Won-Sik ; Lee, You-Yub ; Kim, Dong-Sub ; Oh, Jae-Eung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 619~623
DOI : 10.5050/KSNVN.2008.18.6.619
As higher reliability and accuracy on production facilities are required to detect incipient faults, a diagnostic system for predictive maintenance of the facility is highly recommended. In this paper, it presents a study on the application of vibration signals to diagnose faults for a rotating machinery using the Mahalanobis distance-Taguchi system. RMS, crest factor and Kurtosis that is known as the statistical methods and the spectrum analysis are used to diagnose faults as parameters of Mahalanobis distance.
Questionnaire Study Conducted Around Gimpo International Airport by Using THI - Comparison with the Responses of the Residents at Gimpo and Futenma, Okinawa -
Son, Jin-Hee ; Lee, Kun ; Lee, Seung-Wook ; Chang, Seo-Il ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 624~631
DOI : 10.5050/KSNVN.2008.18.6.624
This study evaluates the impact of aircraft noise on people`s health using the Todai health index(THI). A questionnaire survey was conducted in the vicinity of Gimpo International Airport in Seoul, South Korea, from August 8th to September 9th, 2005. The survey area was divided into three groups based on different aircraft noise levels : area (1) for
WECPNL, area (2) for
WECPNL and area (3) for less than 75 WECPNL. In each area, approximately 200 respondents were sampled. Twelve scale scores of THI are converted to dichotomous variables based on scale scores of 90 percentile value or 10 percentile value in the control group. Logistic regression analysis taking twelve scores converted as the dependent variables and WECPNL(area), age, gender as the independent variables is conducted. Significant dose-response relationships are found in the scale of MOUT, DEPR, NERV, LIFE. Factor analysis was carried out and 2 factors are extracted. Those two factors might be called the "somatic factor" and the "mental factor". The dose-response relationship between two factors and noise seems to be unclear. Unexpectedly the odds ratio of the menatl factor in area (2), where the noise exposure level is lower than that of the area (1), is the highest and the annoyance in this area is also higher than area (1).
Dynamic Modeling of Piezoelectric Energy Harvesting Device and Experiments
Kwak, Moon-K. ; Kim, Ki-Young ; Kang, Ho-Yong ; Kim, Nae-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 632~641
DOI : 10.5050/KSNVN.2008.18.6.632
This paper is concerned with the development of the piezoelectric energy harvesting(PEH) device for ubiquitous sensor node(USN). The USN needs auxiliary power to lengthen its operational life. In this study, the piezoelectric energy harvesting system consisting of a cantilever with a tip mass and piezoelectric wafer was investigated in detail both theoretically and experimentally. The dynamic model for the addressed system was derived using the assumed mode method. The resulting equations of motion were expressed in matrix form, which had never been developed before. The power output characteristics of the PEH was then calculated and discussed. Various experiments were carried out to investigate the charging characteristics of electrical components. Theoretical and experimental results showed that the PEH was able to charge a battery with ambient vibrations but still needed an effective mechanism which can convert mechanical energy to electrical energy and an optimal electric circuit which dissipates small energy.
Comparison of Head-related Transfer Function Models Based on Principal Components Analysis
Hwang, Sung-Mok ; Park, Young-Jin ; Park, Youn-Sik ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 642~653
DOI : 10.5050/KSNVN.2008.18.6.642
This study deals with modeling of head-related transfer functions(HRTFs) using principal components analysis(PCA) in the time and frequency domains. Four PCA models based on head-related impulse responses(HRIRs), complex-valued HRTFs, augmented HRTFs, and log-magnitudes of HRTFs are investigated. The objective of this study is to compare modeling performances of the PCA models in the least-squares sense and to show the theoretical relationship between the PCA models. In terms of the number of principal components needed for modeling, the PCA model based on HRIR or augmented HRTFs showed more efficient modeling performance than the PCA model based on complex-valued HRTFs. The PCA model based on HRIRs in the time domain and that based on augmented HRTFs in the frequency domain are shown to be theoretically equivalent. Modeling performance of the PCA model based on log-magnitudes of HRTFs cannot be compared with that of other PCA models because the PCA model deals with log-scaled magnitude components only, whereas the other PCA models consider both magnitude and phase components in linear scale.
Flow-induced Vibration of Carbon Nanotubes Conveying Fluid
Choi, Jong-Woon ; Gil, Bo-Ramm ; Song, Oh-Seop ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 654~662
DOI : 10.5050/KSNVN.2008.18.6.654
In this paper, flow-induced flutter instability of cantilever carbon nanotubes conveying fluid and modelled as a thin-walled beam is investigated. Non-classical effects of transverse shear and rotary inertia are incorporated in this study. The governing equations and the associated boundary conditions are derived through Hamilton`s principle. Numerical analysis is performed by using extend Galerkin method which enables us to obtain more exact solutions compared with conventional Galerkin method. Cantilevered carbon nanotubes are damped with decaying amplitude for flow velocity below a certain critical value, however, beyond this critical flow velocity, flutter instability may occur. Variations of critical flow velocity with both radius ratio and length of carbon nanotubes are investigated and pertinent conclusion is outlined.
An Experimental Study on the Subjective Response for Water Supply and Drain Installations in Apartment Bathroom
Lee, Tai-Gang ; Ko, Kwang-Pil ; Kim, Hang ; Song, Guk-Gon ; Kim, Sun-Woo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 663~673
DOI : 10.5050/KSNVN.2008.18.6.663
The purpose of this study is to analyze the appropriate evaluation method for the water supply and drain noise of bathroom in apartment and to propose some fundamental idea on its regulation. For this reason, it was studied the acoustical characteristics of water supply and drain noise as modifying the water supply pressure for the washbasins and toilet stools and suggested the optimum evaluation method through psychoacoustic test. As a result of investigation of the levels by evaluating the adjectives and noise sources with 7-step criteria corresponding to each level of plumbing noises and analysis of the correlation between physical evaluation values by comparing the criteria, dB(A), N, and NC, with subject`s response, determination coefficient(
) was shown to be relatively fair or higher ranged from 0.65 to 0.92. It is shown that `Harsh`, `Nervous`, `Unpleasant`, `Distasteful`, and `Repellent` as a second factor are to be appropriate to evaluate plumbing noise. Above these results could be used in basic data establishing KS(Korean Standard) for evaluation and rating procedure and measures reducing these noise.
Development of Meshless Method for Free Vibration Analysis of Arbitrarily Shaped Free Plates Using Local Polar Coordinates
Kang, Sang-Wook ; Atluri, S. N. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 674~680
DOI : 10.5050/KSNVN.2008.18.6.674
A new meshless method for obtaining natural frequencies of arbitrarily shaped plates with the free boundary condition is introduced in the paper. In order to improve the characteristics of convergence and accuracy of the method, a special local polar coordinates system is devised and located for each of nodes distributed along the boundary of the plate of interest. In addition, a new way of decreasing the size of the system matrix that gives natural frequencies of the plate is employed to reduce the amount of numerical calculations, which is needed for computing the determinant of the system matrix. Finally the excellence of the characteristics of convergence and accuracy of the method is shown in several case studies, which indicate that natural frequencies by the proposed method are very accurate and converged swiftly to exact values as the number of boundary nodes increases.
Free Vibration Analysis of a Circular Plate with an Eccentric Circular Hole by the Independent Coordinate Coupling Method
Heo, Seok ; Kwak, Moon-K. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 6, 2008, Pages 681~689
DOI : 10.5050/KSNVN.2008.18.6.681
This paper is concerned with the free vibration analysis of a circular plate with an eccentric circular hole by the Independent coordinate coupling method(ICCM). It was proved in the previous study that the ICCM can accurately predict the natural frequencies and mode shapes of the annular plates and can also be used for the free vibration analysis of the simply-supported circular plate with an eccentric circular hole. In this study, the clamped and free boundary conditions were considered for the circular plate. The numerical results show that the ICCM can be used effectively for the free vibration problem of circular plate with an eccentric hole compared to the finite element method.