On the basis of comparing the electromagnetic characteristics of the beam-ion channel with a traditional medium waveguide for the condition of a step-boundary defined in this paper, the numerical simulation results show that by changing the plasma frequency one can control the electromagnetic working mode in ion channel.

The results proved that for step edge in two dimension, Gabor filter was optimized when the product of the frequency and the spatial constant was close to 1.

In this paper,from the natural characters of step edge of image,we proposed a feature vector that consists of 3 components based on the information measure accordingly.

Addressing to deficiencies of this method,optimum partition method which is widely used in mass analysis is developed to fit thermocline boundary calculation.

Using the simple Green function as basic solution,this paper applies the fast multipole method(FMM) to the higher order boundary element method(HOBEM) so that the computation cost and storage of the computer are reduced to order of O(Nlog N) and O(N) respectively,where N is the number of unknowns.

Inviscid three-dimensional extreme free surface wave motions in infinite water-depth are simulated using a novel quadratic higher-order boundary element model(HOBEM) based on potential theory.

Based on the integral equation,the high order boundary element method (HOBEM) is employed to solve the second order derivative on z direction of potential on the free surface in potential fluent diffraction.

A fully-nonlinear numerical model based on the time-domain higher-order boundary element method(HOBEM) is established to simulate the kinematics of extreme waves.