This paper presents a new method that combines quasi-Monte Carlo quadrature with importance sampling to solve the general rendering equation efficiently. Since classical importance sampling has been proposed for Monte-Carlo integration, first an appropriate formulation is elaborated for deterministic sample sets used in quasi-Monte Carlo methods. This formulation is based on integration by vari...

Atmospheric tomography is a prerequisite step before wavefront perturbations can be corrected in Multi Conjucate Adaptive Optics (MCAO) systems. Recently, the use of a Landweber-Kaczmarz iteration has been proposed to solve the tomography problem. However, due to the geometric partitioning of the update steps in this method, discontinuities in the solution appear that are physically implausible...

the paper presents the semi-numerical solution for the magnetohydrodynamic (mhd) viscous flow due to a stretching sheet caused by boundary layer of an incompressible viscous flow. the governing partial differential equations of momentum equations are reduced into a nonlinear ordinary differential equation (node) by using a classical similarity transformation along with appropriate boundary cond...

A theoretically exact computational boundary is introduced, that is based on modal residual potentials for the spherical geometry. The boundary produces a set of first-order, uncoupled ordinary differential equations for nodal boundary responses, and a set of uncoupled time-stepping equations for modal boundary responses. The two sets are coupled through nodal-modal transformation based on the ...

A computationally efficient method is proposed for computing the simplest normal forms of vector fields. A simple, explicit recursive formula is obtained for general differential equations. The most important feature of the approach is to obtain the “simplest” formula which reduces the computation demand to minimum. At each order of the normal form computation, the formula generates a set of al...

due to the tilt of the platform carrying the synthetic aperture radar(sar), the image formation algorithms(like rda) can not yield to good quality images from the ground. therefore, it is convenient to use a two-step approach for motion compensation in image formation algorithms. in this paper, using an approximated linear model for the motion error and the impact of range compression step of r...

This paper presents a framework for model transformation, organised around Java agents. Internally, the agents are hierarchically composed to build each translation step, offering a fine-grained control over the transformation. Externally, a linear composition of translation steps is used to create a multi-level, forwards transformation from high-level models to executable code, in which interm...

In this study, NiTi thin films were deposited on the glass and NaCl substrates by means of magnetron sputtering method. The influence of aging temperature, over the range 300-500 oC, on phase transformation and mechanical properties of the sputtered NiTi thin films were studied by differential scanning calorimetry (DSC) and nano-indentation assay, respectively. The DSC curves showed that the ag...

Numerical integrators for second-order differential equations with time-dependent high frequencies are proposed and analysed. We derive two such methods, called the adiabatic midpoint rule and the adiabatic Magnus method. The integrators are based on a transformation of the problem to adiabatic variables and an expansion technique for the oscillatory integrals. They can be used with far larger ...