Recent work has highlighted the potential benefits of exploiting ellipsoidal uncertainty set based robust Capon beamformer (RCB) techniques in passive sonar. Regrettably, the computational complexity of forming RCB weights is cubic in the number of adaptive degrees of freedom, which is often prohibitive in practice. For this reason, several low-complexity techniques for computing RCB weights, o...

In multisensor signal processing (underwater acoustics, geophysics, etc.), the initial dataset is usually separated into complementary subspaces called signal and noise subspaces in order to enhance the signal to noise ratio. The Singular Value Decomposition (SVD) is a useful tool to achieve this separation. It provides two orthogonal matrices that convey information on normalized wavelets and ...

Refocusing for time reversed waves propagating in disordered media has recently been observed experimentally and studied mathematically. This surprising effect has a great potential of applications in domains such as medical imaging, underwater acoustics, wireless communications among others. Time refocusing for one-dimensional acoustic waves is now mathematically well understood. In this paper...

Abstract Passive localization of underwater targets was a thorny problem in acoustics. For traditional model-driven passive methods, the main challenges are inevitable environmental mismatch and presence interference noise everywhere. In recent years, data-driven machine learning approaches have opened up new possibilities for However, acquisition processing acoustics data more restricted than ...

Transparent boundary conditions (TBCs) for general Schrödinger– type equations on a bounded domain can be derived explicitly under the assumption that the given potential V is constant on the exterior of that domain. In 1D these boundary conditions are non–local in time (of memory type). Existing discretizations of these TBCs have accuracy problems and render the overall Crank–Nicolson finite d...

Underwater acoustic networks have attracted great attention in the last few years because of its numerous applications. High data rate can be achieved by efficiently modeling the physical layer in the network protocol stack. In Acoustic medium, propagation speed of the acoustic waves is dependent on many parameters such as temperature, salinity, density, and depth. Acoustic propagation speed ca...

We consider a model initial– and boundary–value problem for the third– order wide–angle parabolic approximation of underwater acoustics with depth– and range–dependent coefficients. We discretize the problem in the depth variable by the standard Galerkin finite element method and prove optimal–order L–error estimates for the ensuing continuous–in–range semidiscrete approximation. The associated...

My research focuses on numerical methods for partial differential equations (PDEs) and scientific computing. I have been working on several areas including new Eulerian techniques to approximate high frequency asymptotic solutions to wave phenomena and their related inverse problems, numerical methods for interracial motions, variational and statistical methods for image processing, and Euleria...

In a pure liquid, the behaviour of a gas or vapour microbubble is determined primarily by its size, the ambient pressure and the properties of the surrounding liquid. In practice, however, adsorption of a dissolved substance from the surrounding liquid onto the microbubble surface will often take place, producing a thin coating which can significantly affect both the microbubble's stability and...

We consider the third–order, wide–angle, parabolic approximation of underwater acoustics in a medium with depth– and range–dependent speed of sound in the presence of dissipation and horizontal interfaces. We first discuss the theory of existence and uniqueness of solutions to the problem and derive an energy estimate. We then discretize the problem in the depth variable using two types of Gale...