What is Acoustics@home?

Acoustics@home is a BOINC-based volunteer computing project aimed at solving inverse problems in underwater acoustics. You can contribute to our research by running a free program on your computer.

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In underwater acoustics the notion of geoacoustic inversion refers to a collection of techniques that can be used for the reconstruction of medium parameters. The medium parameters are usually understood as the sound speed profile in water (i.e., the dependence of the sound speed on the depth) and the sound speed and density in the sea bottom sediment layers. Medium parameters reconstruction is of great importance for problems of underwater communication and for the development of underwater navigation systems.

While normally measurements for the geoacoustic inversion are performed using expensive receiver arrays, recently it was shown that single-hydrophone recording of a broadband pulse signal can be also successfully used for estimating the medium parameters.

The method of geoacoustic inversion developed in our study is based on using modal dispersion data. Waveguide dispersion is usually induced by the difference in group velocities of propagation of normal waves of different mode numbers at different frequencies. By using special algorithms of the frequency-time analysis of signals, it is possible to filter out the modal components of a pulse signal from its time series recorded by a single hydrophone. The implementation of this method in practice can be thought of as a solution of an optimization problem in a (very large) discrete search space, and every evaluation of the cost function requires numerous solutions of an acoustic spectral problem. Thus, the whole computational burden can be easily divided into a large number of relatively simple independent tasks, which can be solved using volunteer computing.

News

Report at GRID'2018

15 Sep 2018, 21:38:08 UTC
The report 'Application of BOINC-based volunteer computing for comparison of the geoacoustic inversion algorithms efficiency.' was made in Dubna at the conference GRID'2018. In this report, results obtained in Acoustics@home are discussed. The presentation is available online

На 8-ой международной конференции GRID'2018 в Дубне был сделан доклад по результатам Acoustics@home.

On the current experiment

14 May 2018, 9:32:02 UTC
In the current experiment, we study the accuracy of the sound speed profile reconstruction in a shallow-water waveguide using a dispersion-based geoacoustic inversion scheme. This problem was transformed into a problem of black-box minimization of a certain mismatch function. A sound speed profile is considered a piecewise-linear function with fixed uniformly-spaced nodes. At these nodes, the values of sound speed are obtained in the course of inversion. The main novelty is that the depths of the sound speed profile nodes are also considered inversion parameters. Note, that in the previous experiment held in Autumn 2017 the depths were constant.

В текущем эксперименте исследуется точность восстановления профиля скорости звука в волноводе мелкого моря с использованием схемы обращения, основанной на данных дисперсии. Эта задача была сведена к задаче оптимизации вида 'черный ящик'. Профиль скорости звука рассмотрен как линейно-кусочная функция с фиксированными узлами, расположенными равномерно. Значения профиля скорости звука в этих узлах вычисляются в результате решения задачи обращения. Основной новизной является то, что глубины профиля скорости звука также рассматриваются как варьиреумые параметры. Отметим, что в предыдущем эксперименте, проведенном осенью 2017 года, значения глубин были константными.
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