Scattering properties of a material are changed when the material is injected with small acoustically soft particles. It is shown that its new scattering behavior can be understood as a solution of a potential scattering problem with the potential q explicitly related to the density of the small particles. In this paper we examine the inverse problem of designing a material with the desired foc...

AS scientific simulation software becomes more complicated, the scientific-software implementer’s need for component tests from new model developers becomes more crucial. The community’s ability to follow the basic premise of the Scientific Method requires independently repeatable experiments, and model innovators are in the best position to create these test fixtures. Scientific software devel...

Nonlinear stochastic optimal control problems are treated that are nonlinear in the state dynamics, but are linear in the control. The cost functional is a general function of the state, but the costs are quadratic in the control. The system is subject random fluctuations due to discontinuous Poisson noise that depends on both the state and control, as well as due to discontinuous Gaussian nois...

with fixed initial data x(t = x where x is the n-dimensional o) o' state vector, u is the r-dimensional vector control function, A(t) , B(t) are the nxn, nxr matrix functions, respectively. A(t), B(t), are assumed to be piecewise continuous for t ~ to on any finite in­ terval. A control function u(t) is said to be admissible if it is measur­ able over any finite interval and takes its values fr...

Measuring surface fluxes using the surface renewal (SR) method requires a set of programmatic algorithms for tabulation, algebraic calculation, and quality control. Field experiments were conducted over a variety of surface conditions to determine the shortest valid time averaging period for the SR method. Because the SR method utilizes high frequency (20 Hz+) measurements, some steps in the fl...

Evaluating the power densities emitted by GSM1800 and GSM900 BTS antennas isconducted via two methods. Measurements are carried out in half a square meter grids around twoantennas. CST Microwave STUDIO software is employed to estimate the power densities in order fordetailed antenna and tower modeling and simulation of power density. Finally, measurements obtainedfrom computational and experime...

0045-7825/$ see front matter 2012 Elsevier B.V. A http://dx.doi.org/10.1016/j.cma.2012.06.012 ⇑ Corresponding author. E-mail address: [email protected] (J.E. Andrad This paper presents a method within the family of the discrete element method (DEM) capable of accurately capturing grain shape by using Non-Uniform Rational Basis-Splines (NURBS). The new method, called GEM, bypasses one of the ...