the stolt (f-k) migration algorithm is a direct (i.e. non-recursive) fourier-domain technique based on a change of variables (or equivalently, a mapping) that converts the input spectrum to the output spectrum. the algorithm is simple and efficient but limited to constant velocity. a v(z)(f-k) migration method, capable of very high accuracy for vertical variations of velocity, can be formulated...

introduction : due to the importance of laser light penetration and propagation in biological tissues, many researchers have proposed several numerical methods such as monte carlo, finite element and green function methods. among them, the monte carlo method is an accurate method which can be applied for different tissues. however, because of its statistical nature, monte carlo simulation requi...

This paper introduces a fast high-resolution imaging algorithm designed for ultra-wideband radar, and combines modified Kirchhoff migration and frequency-wavenumber (F-K) migration. The proposed algorithm also uses the texture method and inverse boundary scattering transform to calculate efficiently the integral arising in modified Kirchhoff migration, and thus enabling the integral in the F-K ...

We implement Stolt-stretch time migration with an analytical formulation for the optimal stretch parameter and show how it improves the quality of imaging. By a cascaded f-k migration approach with this algorithm, we manage to obtain time migration results on real data comparable to Gazdag’s phase-shift method, with a high accuracy for steeply deeping events at a computational cost dramatically...

objective(s): in order to grow cells in a three-dimensional (3d) microenvironment, self-assembling peptides, such as puramatrix, have emerged with potential to mimic the extracellular matrix. the aim of the present study was to investigate the influence of the self-assembling peptide on the morphology, survival, proliferation rate, migration potential, and differentiation of human meningioma st...

PURPOSE To evaluate the dose effect of vitamin K3 on wound healing mechanisms. METHODS Conjunctival fibroblasts were incubated for 24 hours. An artificial wound was made and the cells were incubated with fresh medium plus doses of vitamin K3 to be tested. Wound repair was monitored at 0, 18, 24, and 48 hours. Proliferation was measured in actively dividing cells by [(3)H]thymidine uptake. Six...

in iran, the majority of vegetable oil producers , use pet for packaging their products . due to high solubility of pet oligomers in the oils , and shelf life of liquid oils , it is expected that some compounds migrate into the oil . this study was carried out to determine the amount of migration of terephtalates from pet bottles into sunflower oil and the effect of temperature and storage time...

A well-known clustering algorithm is K-means. This algorithm, besides advantages such as high speed and ease of employment, suffers from the problem of local optima. In order to overcome this problem, a lot of studies have been done in clustering. This paper presents a hybrid Extended Cuckoo Optimization Algorithm (ECOA) and K-means (K), which is called ECOA-K. The COA algorithm has advantages ...