Dowan Kim (E-mail : marinater@daum.net) Beomsoo Han (E-mail : sc17921792@naver.com) Sungho Mun (E-mail : smun@seoultech.ac.kr) Deok-Soon An (E-mail : dsan@kict.re.kr) ABSTRACT PURPOSES : This study is to predict the Sound Pressure Level(SPL) obtained from the Noble Close ProXimity(NCPX) method by using the Extended Kalman Filter Algorithm employing the taylor series and Linear Regression Analysis based on the least square method. The objective of utilizing EKF Algorithm is to consider stochastically the effect of error because the Regression analysis is not the method for the statical approach. METHODS : For measuring the friction noise between the surface and vehicle s tire, NCPX method was used. With NCPX method, SPL can be obtained using the frequency analysis such as Discrete Fourier Transform(DFT), Fast Fourier Transform(FFT) and Constant Percentage Bandwidth(CPB) Analysis. In this research, CPB analysis was only conducted for deriving A-weighted SPL from the sound power level in terms of frequencies. EKF Algorithm and Regression analysis were performed for estimating the SPL regarding the vehicle velocities. RESULTS : The study has shown that the results related to the coefficient of determination and RMSE from EKF Algorithm have been improved by comparing to Regression analysis. CONCLUSIONS : The more the vehicle is fast, the more the SPL must be high. But in the results of EKF Algorithm, SPLs are irregular. The reason of that is the EKF algorithm can be reflected by the error covariance from the measurements. Keywords extended kalman filter algorithm, Sound Pressure Level(SPL), constant percentage bandwidth analysis, NCPX(Noble Close ProXimity) method, Fast Fourier Transform(FFT) analysis Corresponding Author : Mun, Sungho, Associate Professor Department of Civil Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Nowon-gu, Seoul, 139-743, Korea Tel : +82.2.970.9014 E-mail : smun@seoultech.ac.kr International Journal of Highway Engineering http://www.ksre.or.kr/ ISSN 1738-7159 (print) ISSN 2287-3678 (Online) 59
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Bongkoo, Han, Dowan, Kim, Sungho, Mun, and Hayeon, Kim. (2013) A study of Eliminating the Vehicle Noise of Engine RPM from the Friction Noise between Tire and Road Pavement by Using a NCPX method. Journal of the Korean Society of Road Engineers, Vol. 15, No. 4. pp. 31-42. Dowan, Kim, Deoksoon, An and Sungho, Mun. (2013) A study on Development of a Prediction Model for the Sound Pressure Level Related to Vehicle Velocity by Measuring NCPX Measurement. Journal of the Korean Society of Road Engineers, Vol. 15, No. 4. pp. 21-29. Dowan, Kim, Yeongsun, Jang and Sungho, Mun. (2013) A Study on the Vibration Decibel Related to the Shape of Rumble Strip Located on the Highway Tollgate. Journal of the Korean Society of Road Engineers, Vol. 15, No. 6. pp. 93-101. Dowan, Kim, Sooahn, Kwon, Yoonshin, Bae and Sungho, Mun. (2013) An Analysis of the Asphalt/Concrete Roads Noise in Seoul. Journal of the Seoul Institute, Vol. 14, No. 2. pp. 193-209. Dowan, Kim, Sungho, Mun, Deoksoon, An and Hyeonjang, Son. (2013) A study on Development of the Prediction Model Related to the Sound Pressure in Terms of Frequencies, Using the Pass-by and NCPX Method. Journal of the Korean Society of Road Engineers, Vol. 15, No. 6. pp. 79-91. Mun, S., and Cho, D-S and Choi T-M. (2007) Influence of pavement surface noise : Korea Highway Corporation test road. Canadian Journal of Civil Engineering, Vol. 34. pp. 809-816. Mun, S., and Cho, D-S. (2008) Development of a highway traffic noise prediction model that considers various road surface types. Applied Acoustics, Vol. 69. pp. 1120-1128. Mun, S., and Cho, D-S. (2008) Determination of the sound power levels emitted by various vehicles using a novel testing method. Applied Acoustics, Vol. 69. pp. 185-195. Mun, S., and Cho, D-S. (2009) Noise measuring technique and field evaluation based on the effects of vehicles and pavement types. Canadian Journal of Civil Engineering, Vol. 36. pp. 1816-1824. Sungho, Mun, Kwang-ho, Lee, Dae-Seung, Cho, (2011) Software Developmet of the Traffic Noise Prediction Based on the Frictional Interaction between Pavement Surface and Tire. Journal of the Korean Society of Road Engineers, Vol. 13, No. 2. pp. 67-75. Sangyum, Lee, Junghoon, Jin, Sungho, Mun, Hak-Ryong, Moon. (2012) Study on the Noise Characteristics of Bridge Deck Pavements in Seoul Inner Ring Road. Journal of the Korean Society of Road Engineers, Vol. 14, No. 2. pp. 19-28. Sangyum, Lee, In-Tae, Kim, Sungho, Mun, Sooahn, Kwon. (2012) Study on the Functional Evaluation of Permeable Asphalt Concrete Pavement in Seoul City. Journal of the Korean Society of Road Engineers, Vol. 14, No. 3. pp. 33-39. 66 International Journal of Highway Engineering Vol.16 No.5