The finite difference time domain (FDTD) method is commonly used as a numerically accurate way of propagating sound. However, it requires extensive computation. We present a simple method for accelerating FDTD. Specifically, we modify the FDTD update loop to prioritize computation where it is needed most in order to faithfully propagate waves through the simulated space. We estimate for each po...

The scope of the paper is the simulation of the sound field radiated by a string in the time domain. Different time domain methods have been successfully implemented for string simulations. These methods not only perform real-time string sound synthesis, but also pressure and particle velocity generated near strings can be obtained. This is very useful to analyze sound field interaction with ex...

In this paper, the Specific Absorption Rate (SAR) distribution in a human head irradiated by an obliquely incident electromagnetic plane wave is studied. A simple planar multi-layered structure is used to model the human head. Moreover, the steady state thermal elevation distribution is calculated by solving the bioheat equation using the finite difference time domain (FDTD) method. Both types ...

In this paper, an alternating implicit block method for solving two dimensional scalar wave equation is presented. The new method consist of two stages for each time step implemented in alternating directions which are very simple in computation. To increase the speed of computation, a group of adjacent points is computed simultaneously. It is shown that the presented method increase the maximu...

The performances of absorbing boundary conditions (ABCs) in four widely used finite difference time domain (FDTD) methods, i.e. explicit, implicit, explicit staggered-time, and Chebyshev methods, for solving the time-dependent Schr dinger equation are assessed and compared. The computation efficiency for each approach is also evaluated. A typical evolution problem of a single Gaussian wave pack...

[1] This study explores a simulation of ice cloud optical properties similar to those observed using the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), a dual-wavelength (0.532 and 1.064 mm) lidar. The goal is to better understand the sensitivity of the color ratio (the ratio of the backscatter coefficients at the wavelengths of 1.064 and 0.532 mm) to ice particle habit. The single-...

In this paper we demonstrate low loss transmission both above and below the primary band-gap for a photonic crystal (PC) super-prism device consisting of 600 lattice periods. By modifying the refractive index of the holes, we reduce overall insertion loss to just 4.5 dB across the entire visible spectrum. We show that the remaining loss is predominantly due to impedance mismatch at the boundari...

This paper analyzes dielectric resonators using the FDTD method. Resonant frequencies and quality factors are calculated using Prony's method instead of the classical FFT

We developed a matrix theory that applies to any cylindrically symmetric fiber surrounded with Bragg cladding, which includes both the Bragg fibers and the recently proposed dielectric coaxial fibers. In this formalism, an arbitrary number of inner dielectric layers are treated exactly and the outside cladding structure is approximated in the asymptotic limit. An estimate of the radiation loss ...

The Finite Difference Time Domain (FDTD) method is becoming increasingly popular for room acoustics simulation. Yet, the literature on grid excitation methods is relatively sparse, and source functions are traditionally implemented in a hard or additive form using arbitrarily-shaped functions which do not necessarily obey the physical laws of sound generation. In this paper we formulate a sourc...