Jun TangWestlake University · School of Engineering
Jun Tang
PhD
About
12
Publications
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Introduction
Additional affiliations
September 2020 - December 2022
April 2019 - September 2020
August 2012 - March 2019
Publications
Publications (12)
The performance of warping transformation in diminishing the error in underwater source-bearing estimation, caused by horizontal refraction effects (also named 3D effects), is studied. First, the capability of warping transformation for separating the normal modes, as well as their direct and horizontally refracted paths, in a standard Acoustical S...
Some notes on the derivation of the modal amplitude equation for the problem of P-SV wave propagation in the oceans are presented. Firstly, the derivation in the case of a line source is revisited. Secondly, the extension of the derivation to the case of a point source, though not fully accomplished, is discussed.
A propagation matrix method for the solution of the parabolic equation in ocean acoustics is presented, where the sound fields at an arbitrary distance are expressed as a product of the initial fields and a sequential multiplication of the propagation matrices. The method
contains two main calculation steps, i.e., producing and multiplying the prop...
Modelling of sound propagation and analyzing of sound fields are important parts in underwater acoustics. With the frequency band of sonar being extended towards low frequency, it is necessary to consider bottom elasticity in sound propagation modelling, because low-frequency sound waves can penetrate deep into the elastic bottom, and then transmit...
For the application of vector hydrophone in bearing estimation, effects of horizontal refraction on vector-field characteristics in the problem of three-dimensional (3D) underwater sound propagation are studied. Through theoretical analysis, it is shown that with the presence of horizontal refraction, the horizontal displacement is elliptically pol...
In this study the method of source images for the problem of sound propagation in a penetrable wedge [G. Deane and M. Buckingham, J. Acoust. Soc. Am. 93 (1993) 1319–1328] is revisited. This solution is very important three-dimensional (3D) benchmark in computational underwater acoustics, since a wedge bounded from above by the sea surface and overl...
A three-dimensional (3D) parabolic equation (PE) model for sound propagation in a seismo-acoustic waveguide is developed in Cartesian coordinates, with x, y, and z representing the marching direction, the longitudinal direction, and the depth direction, respectively. Two sets of 3D PEs for horizontally homogenous media are derived by rewriting the...
The parabolic equation (PE) method and the finite element method (FEM) are both applied to modelling of seismic wave propagation in two issues: nuclear explosion and wind turbine noise. Explosion inside the elastic layer is modelled as delta function and its derivatives in both P and S wave equations in PE, while as the combination of normal and ta...
This work is aimed at exploring characteristics of horizontal refraction in three-dimensional sound propagation. The horizontal refraction angle is used as the indicator for evaluating strength of horizontal refraction effects. The horizontal refraction angle, as well as the sound fields, in a series of wedge-shaped ocean waveguides with different...
The perfectly matched layer (PML) is an effective technique for truncating unbounded domains with minimal spurious reflections. A fluid parabolic equation (PE) model applying PML technique was previously used to analyze the sound propagation problem in a range-dependent waveguide (Lu and Zhu, 2007). However, Lu and Zhu only considered a standard fl...
Broadband sound propagation in shallow water is studied in this work. It is essential for a shallow water sound propagation model to involve the effects of bottom interaction and range-dependence. Therefore, a realistic model that consists of a fluid overlying an elastic sloping bottom is treated in this paper, where the effects of shear waves are...
Questions
Questions (6)
I've been initiating my new research topic personal sound zone (also called personal audio, multi-zone sound reproduction, etc), which is a branch of spatial sound reproduction.
The consistency of the amplitude response and phase response (related with the latency consistency) between the loudspeaker-array elements are important for accurately controlling the sound fields in the space. Thus, I'm wondering if there is any standard approach to do the calibration between the array elements.
As we know, the calibration of a microphone array is straightforward. This is because the mics receive the signals, and we can easily evaluate the channel consistency with the received signals. While in order to calibrate a loudspeaker array, I assume, one has to consider the overall response of loudspeaker-room-mic. Is that right?
I'm new in this study. I don't know if there is any stand approach or any open source tool box for this. Will be appreciate if anyone can give some advice. Thank you.
We know that the pre-processing of speech recognition includes echo cancellation, de-reverberation, audio enhancement, noise suppression, and so on. Is there a comprehensive toolbox/code for that purpose that can be a start point for a beginner?
We know that by using a microphone array we gain extra SNR. In the meantime, vector sensors are also with that advantage, and moreover, able to achieve that with a single sensor without the necessity of using an array. However, the reality is nowadays most acoustic products are using a microphone array instead of a vector sensor. Why is that?
Microphone array is heavily used in acoustical techniques such as detection, DOA, target tracking and so on. I'm wondering if there is a user-friendly code or toolbox that can be used for demos in the classroom for an acoustic course for master/bachelor students.
Noise suppression is an important link in audio technology. In voice interaction inside cars, a new challenge is the tackling of tire-pavement noise which is not considered in the design of the currently popular VI products.
Just out of curiosity, I'm wondering if there is any open source data for tire-pavement noise? Data measured inside the cars are even better.
As we know, the radiation condition is what we use to ensure the uniqueness of the solutions of partial differential equations such as wave equations and heat equations.
"the sources must be sources, not sinks of energy. The energy which is radiated from the sources must scatter to infinity; no energy may be radiated from infinity into ... the field."
Above is the words (the mostly used English version) by Sommerfeld for the description of radiation condition, and it is quoted in many books on partial differential equations. According to these books, the above words are written a book of Sommerfeld , "Partial differential equations in Physics".
I would like to ask, in which page is the above sentence?
(I have an electric version of this book, but in the format of djvu, which is extremely difficult to go over quickly. If anybody know the place of this sentence, please kindly tell me.)
Many thanks!!!
