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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 16, Issue 12 - Dec 2006
Volume 16, Issue 11 - Nov 2006
Volume 16, Issue 10 - Oct 2006
Volume 16, Issue 9 - Sep 2006
Volume 16, Issue 8 - Aug 2006
Volume 16, Issue 7 - Jul 2006
Volume 16, Issue 6 - Jun 2006
Volume 16, Issue 5 - May 2006
Volume 16, Issue 4 - Apr 2006
Volume 16, Issue 3 - Mar 2006
Volume 16, Issue 2 - Feb 2006
Volume 16, Issue 1 - Jan 2006
Selecting the target year
A Study on the Data Transmission of Multiple Sensor Using Code Division Multiple Access
Mun, Se-Sang ; Park, Woo-Il ; Kim, Woo-Shik ; Cho, Hyang-Duck ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1093~1099
DOI : 10.5050/KSNVN.2006.16.11.1093
In general, a measuring instrument of sound noise use only one wired channel by one sensor. Therefor the measuring instrument use wired cables as the number of channels are provided by instrument. In a point of observed target it needs data from multiple sensors and In case of measured point is a large numbers the environment of constitution would be complicated because that is in need of channel and cable. So we need the method that can improve the existing transmission channel and cable environment even the measured point is increased. If we use the Code Division Multiple Access(CDMA) we transmit a large numbers of sensor data by using a common transmission channel. We present the method that transmits data of multiple sensor to wireless by using CDMA. This method can simplify the measurement environment dramatically when collecting data by using multiple sensor. We expect this study to contribute the part of multiple access technology and relation technologies on the measuring environment.
Performance Enhancement of Pneumatic Vibration Isolator in Low Frequency by Time Delay Control
Oh, Ki-Yong ; Shin, Yun-Ho ; Lee, Jeung-Hoon ; Kim, Kwang-Joon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1100~1107
DOI : 10.5050/KSNVN.2006.16.11.1100
As environmental vibration requirements on precision equipment become more stringent, use of pneumatic isolators has become more popular and their performance is subsequently required to be further improved. Performance of passive pneumatic isolators is related to various design parameters in a complicated manner and, hence, is very limited especially in low frequency range by chamber volume. In this study, transmissibility behavior of the pneumatic isolators depending on frequency and dynamic amplitude are presented. Then, an active control technique, time delay control, which is adequate for a low frequency nonlinear system, is applied. A procedure of applying the time delay control law to a pneumatic isolator is presented and it`s effectiveness in the transmissibility performance is shown. Comparison between passive and active pneumatic isolators is made based on simulation.
Analysis for Anti-shock Characteristics of Underwater Acoustic Transducers to the Explosive Shock
Goh, Byeong-Jun ; Seo, Hee-Seon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1108~1114
DOI : 10.5050/KSNVN.2006.16.11.1108
Underwater acoustic transducers can be exposed to a underwater explosive shock caused by various types of underwater weapon. So, a robust anti-shock design is required for transducers to endure the underwater explosive shock. To check the anti-shock characteristics of a transducer, underwater explosive shock test is needed. The conditions of underwater explosive shock test are set up referring to various oversea explosive shock test specifications, and the explosive shock pressure values are calculated according to those conditions. Transient analyses art: carried out for two kinds of underwater acoustic transducer model to verify the anti-shock characteristics. The applied model has robust anti-shock characteristics enough to endure the explosive shock up to 2300 psi. In the future, the transducer design should be certified through the fields test, and modified if needed.
Vibration Characteristics of a Nuclear Fuel Rod in Uniform Axial Flow
Jeon, Sang-Youn ; Suh, Jung-Min ; Kim, Kyu-Tae ; Park, Nam-Gyu ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1115~1123
DOI : 10.5050/KSNVN.2006.16.11.1115
Nuclear fuel rods are exposed to axial flow in a reactor, and flow-induced-vibration due to the flow usually causes damage in the fuel rods. Thus a prior knowledge about dynamic behavior of a fuel rod exposed to the flow condition should be provided. This paper shows that dynamic characteristics of a nuclear fuel rod depend on axial flow velocity. Assuming small lateral displacement, the effects of uniform axial flow are investigated. The analytic results show that axial flow generally reduces fuel rod stiffness and raises its damping in normal condition. Also, the critical axial velocities which make the fuel rod behavior unstable were found. That is, solving generalized eigenvalue equation of the fuel rod dynamic system, the eigenvalues with positive real part are detected. Based on the simulation results, on the other hand, it turns out that the ordinary axial flow in nuclear reactors does not affect to stability of a nuclear fuel rod even in the conservative condition.
A Study on the Evaluation Method of Sound Power for a Travelling Vehicle Using CPX and Pass-by Measurements
Choi, T.M. ; Moon, S.H. ; Seo, Y.G. ; Kim, J.H. ; Kim, B.H. ; Bae, H.J. ; Ji, W.J. ; Cho, D.S. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1124~1131
DOI : 10.5050/KSNVN.2006.16.11.1124
This paper presents a novel method to determine sound power level(PWL) emitted by a travelling vehicle for road traffic noise simulation. The PWL is evaluated by the equivalent sound pressure level (SPL) measured by close proximity method and the sound power correction factor derived from the maximum SPL measured by pass-by method and the propagation attenuation of vehicle noise during the pass-by measurement. Using the method, we derive the empirical formula for PWL estimation in 1/1-octave and overall frequency bands for 8 vehicles (automobile, SUV, small truck, large bus, trailer, 3 dump trucks) tested at two road surfaces (dense graded asphalt, 30mm transverse tinning concrete) of Korean highway test road. The suggested approach, if securing sufficient data to represent the acoustic characteristics of all vehicle types, has il strong merit to be able to evaluate sound power levels for any combination of vehicle categories and traffic volumes.
Study for Characteristics of DDAM using MIL-S-901D Shock Test and Transient Response Analysis
Song, Oh-Seop ; Kim, Yong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1132~1139
DOI : 10.5050/KSNVN.2006.16.11.1132
Non-contact underwater explosions against surface ship could cause extensive equipment damage during wartime service. Thus, the need to develop methods for the design of shock resistant equipment structures and systems was strongly established. In analytical methods, DDAM(Dynamic Design and Analysis Method) and transient repsonse method are used for ship shock design. In this paper, to analyze the characteristics of DDAM, medium weight shock test, DDAM and transient response analysis for missile system equipment are performed.
Study on Transmission Loss in Smart Panel Using Admittance
Zhao, Lijie ; Kim, Jae-Hwan ; Kim, Heung-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1140~1148
DOI : 10.5050/KSNVN.2006.16.11.1140
In this paper, transmission loss of smart panel was investigated using piezoelectric shunt damping. Admittance of piezoelectric system was introduced to represent electro-mechanical coupling of smart panel and to predict the performance of shunt damping. Finite element method was used to obtain numerical admittance. In order to illuminate the effect of noise reduction in the shunt system, transmission loss of the smart panel was investigated. Two models were considered to show the relation between admittance and transmission loss of smart panel. It was observed that admittance of piezoelectric system could be used as a design index of smart panel.
Translation-invariant Wavelet Denoising Method Based on a New Thresholding Function for Underwater Acoustic Measurement
Choi, Jae-Yong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1149~1157
DOI : 10.5050/KSNVN.2006.16.11.1149
Donoho et al. suggested a wavelet thresholding denoising method based on discrete wavelet transform. This paper proposes an improved denoising method using a new thresholding function based on translation-invariant wavelet for underwater acoustic measurement. The conventional wavelet thresholding denoising method causes Pseudo-Gibbs phenomena near singularities due to the lack of translation-invariant of the wavelet basis. To suppress Pseudo-Gibbs phenomena, a denoising method combining a new thresholding function based on the translation-invariant wavelet transform is proposed in this paper. The new thresholding function is a modified hard-thresholding to each node according to the discriminated threshold so as to reject unknown external noise and white gaussian noise. The experimental results show that the proposed method can effectively eliminate noise, extract characteristic information of radiated noise signals.
Measuring Young`s Modulus of Materials by Using Accelerometer
Sohn, Chang-Ho ; Park, Jin-Ho ; Yoon, Doo-Byung ; Chong, Ui-Pil ; Choi, Young-Chul ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1158~1164
DOI : 10.5050/KSNVN.2006.16.11.1158
For the description of the elastic properties of linear objects a convenient parameter is the ratio of the stress to the strain, a parameter called the Young`s modulus of the material. Young`s modulus can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material. Conventional method for estimating Young`s modulus measured the ratio of stress to corresponding strain below the proportional limit of a material using a tensile testing machine. But the method needs precision specimens and expensive equipment. In this paper, we proposed method for estimating Young`s modulus using accelerometer. The basic idea comes from that the wave velocity is different as the Young`s modulus. To obtain Young`s modulus, a group velocity is obtained. It is difficult to measure group velocity. This is because plate medium has a dispersive characteristics which has different wave speed as frequency. In this paper, we used Wigner-Ville distribution to measure group velocity. To verify the proposed method, steel and acryl plate experiments have been performed. Experimental results show that the proposed method is powerful for estimating Young`s modulus.
Design and Control of Jetting Dispenser Driven by Piezoelectric Actuator
Choi, Min-Kyu ; Nguyen, Quoc-Hung ; Yun, Bo-Young ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1165~1171
DOI : 10.5050/KSNVN.2006.16.11.1165
This paper presents a new type of jetting dispenser for the integrated circuit (IC) fabrication and surface mount technology The proposed system is featured by the piezoelectric actuator and hydraulic magnification device. After describing structural component of the dispensing mechanism and its operation principle, both the fluid modeling and the hydraulic magnification modeling are undertaken with a lumped-parameter method based on the analogy of the fluid system and mechanical system. A mathematical governing equation is then derived by integrating the fluid model with the mechanical model of the driving piston and piezoelectric actuator. Subsequently, in order to achieve a desired dispensing amount, control algorithm adjusting duty cycle of the driving voltage is synthesized and control responses are presented in time domain.
On-line Strain Measurement of Rotating Blade Using Fiber Bragg Grating Sensors and Beam Coupler
Lee, In-Jae ; Lee, Jong-Min ; Lee, Sang-Bae ; Hwang, Yo-Ha ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 11, 2006, Pages 1172~1178
DOI : 10.5050/KSNVN.2006.16.11.1172
Measurement of blade strain with sensors directly installed on the blade has one critical issue, how to send the sensor signal to the ground. Strain-gauges have been dominantly used to directly measure stress of a blade and either a slip ring or a telemetry system has to be used to send measured signal to the ground. However, both systems have many inherent problems and sometimes very severe limitations to be practically used. In this paper, new on-line strain monitoring method using. FBG(Fiber Bragg Grating) sensors and a beam coupler is introduced. Measurement of rotor stress using FBG sensors is nothing new, but unlike other system which installs all necessary instruments on the rotor and use telemetry system to send data to the ground, this system makes use of light`s unique characteristic - light travels through space. In this new approach, single optical fiber with many FBG sensors is installed on the blade and all other necessary instruments can be installed at ground thereby giving tremendous advantages over slip ring or telemetry system. A reference sensor is also introduced to compensate the beam coupler`s transmission loss change due to rotation. The suggested system`s good performance is demonstrated with experiments.