Dynamic importance weighting is proposed as a Monte Carlo method that has the capability to sample relevant parts of the configuration space even in the presence of many steep energy minima. The method relies on an additional dynamic variable (the importance weight) to help the system overcome steep barriers. A non-Metropolis theory is developed for the construction of such weighted samplers. A...

An integration algorithm that conjugates a Method of Lines (MOL) strategy based on finite differences space discretizations, with a collocation strategy based on increasing level dyadic grids is presented. It reveals potential either as a grid generation procedure and a Partial Differential Equation (PDE) integration scheme. It copes satisfactorily with a example characterized by a steep travel...

One-way recursive wavefield extrapolation and migration has many advantages over other wavefield extrapolation methods. The method can handle complex models and is robust. However, the extrapolation of turning waves is one important omission of one-way wavefield extrapolation In this paper a new hybrid approach for the imaging of steep salt flanks is presented: CFP redatuming is used to redatum...

Landslides are one of the critical natural hazards that cause human, infrastructure, and economic losses. Risk of catastrophic losses due to landslides is significant given sprawled urban development near steep slopes and the increasing proximity of large populations to hilly areas. For reducing these losses, a high-resolution digital terrain model (DTM) is an essential piece of data for a qual...

We propose an image-domain velocity model building method using the two-way wave equation and extended seismic images. We show that common-image-point gathers can effectively extract velocity information from steep reflections imaged with the two-way wave propagator. Such gathers have the advantages over conventional common-image gathers that they are capable of characterizing reflections with ...

In this paper a time-dependent moving-grid method is described to numerically solve timedependent partial differential equations (PDEs) in two space dimensions involving fine scale structures such as steep moving fronts, emerging steep layers, pulses and shocks. The method is based on an equidistribution principle along coordinate lines in the two spatial directions. Smoothing in the spatial di...

We introduce the concept of fractional spectral vanishing viscosity (fSVV) to solve conservations laws that govern the evolution of steep fronts. We apply this method to the two-dimensional surface quasigeostrophic (SQG) equation. The classical solutions of the inviscid SQG equation can develop finite-time singularities. By applying the fSVV method, we are able to simulate these solutions with ...

proper conditions for producing crude beta-galactosidase from waste materials were de-termined. this enzyme is to be used in the production of lactose-hydrolyzed milk. whey permeate was used as a basic medium. twenty seven treatments were developed by 3 vary-ing factors of: yeast extract (1, 2, and 3 %), wheat steep liquor (1, 2, and 3 %), and whey powder (0.5, 1, and 1.5 %). crude enzyme extra...