方向积分与多元非张量积小波的构造

以方向积分为工具,给出一种利用一元小波构造二元非张量积小波的方法,从而为继承和提高现有张量积小波的优秀性质提供了可能性.

用作图法判定航空相机TDI CCD积分方向

由于Time Delay and Integration CCD(TDI CCD)是一种类似面阵结构的线阵输出CCD,其光电荷转移具有一定的方向性,所以TDI CCD图像传感器的积分方向与CCD成像运动方向必须保持一定的关系才能成像。本文以推扫成像相机和摆扫成像相机为例,介绍了一种基于高斯成像原理的作图法,用以确定TDI CCD积分方向与传感器成像运动方向的关系,分析和论证表明,TDI CCD的积分方向必须与地物在像面上的像移方向一致。实践证明这种方法可以清楚、简便、快速地确定TDI CCD的积分方向,从而确定TDI CCD的安装方向,适宜在实际的工程设计中采用。

基于方向灰度积分曲线特征的织物疵点检测算法研究

针对于断纱、缺纱、穿错、粗纱等这类结构型织物疵点,由于其具有灰度跳变不明显、疵点面积小的特征在疵点检测过程中难以检测这一问题,本文结合织物图像自身的纹理特征及结构型疵点的方向性特征,创新性地提出基于方向灰度积分曲线特征的织物疵点检测方法,将二维织物图像的疵点检测转化为对一维灰度积分曲线特征的分类识别。该方法通过对输入的图像提取垂直水平方向灰度积分波形曲线,并对积分曲线提取了包括平均值、方差、能量等14个波形特征,然后利用可优化SVM分类算法对提取特征进行疵点判别。通过对漏针、断纱、并经、粗纱等疵点进行检测试验,结果表明,本文提出的疵点检测方法不仅对检测灰度跳变较小的结构型疵点具有较好的检测效果,检测准确率达到了94.34%,而且检测速度快,可以满足实时检测的速度要求。

基于积分方法的二元B样条多尺度细分

利用二元B样条的积分定义方法,构造其M(M≥2)尺度的加细方程.所得结果可概括现有的二元Box样条和最小支集的二元B样条的细分方法.

移动荷载作用下饱和土—桩系统动力响应的积分方程法(英文)

采用Muki虚拟桩法,在频域内建立了移动荷载作用下饱和土体—桩系统相互作用的第二类Fred-holm积分方程,通过离散积分方程与傅里叶逆变换,得到了时间、空间域内桩—土的动力响应,并通过数值计算,分析结果表明:当荷载速度较高时,桩侧有明显的负摩阻力,同时桩顶上部有较大的负孔压.

论由Dirac符号组成的算符之积分——从牛顿-莱布尼兹积分谈起

指出牛顿-莱布尼兹积分的一个新的发展方向,即对量子力学中由Dirac符号组成的算符之积分的必要性和可行性展开讨论,并指出其广泛的应用范围.从而发展Dirac符号法,使其有更多的物理应用.

变量核分数次积分算子的有界性估计

利用球面调和函数展开及插值的方法,获得了方向分数次积分算子的混合范数有界性估计;在此有界性估计的基础上,再借助于旋转法,得到了变量核分数次积分算子的部分有界性证明.所得结果扩充了分数次积分算子的若干有界性结论.

多方向线积分的梯度特征

典型的梯度特征包括HOG(梯度方向直方图)、Shapelet及Edgelet等,这些特征被广泛用于目标检测、目标识别、图像检索及场景分类等领域。针对HOG特征运算复杂度高的问题,提出了一种新的多方向线积分的梯度特征(MDIG)。通过避免计算梯度方向并利用积分图,该特征简化了计算过程,提高了计算速度,因而便于在DSP等硬件上实现。实验中新特征被应用于人体头肩检测。实验结果表明当使用AdaBoost算法训练分类器时,该特征的描述能力与HOG相当,同时其计算时间仅为HOG的1/3,整体性能优于HOG。最后,针对梯度特征的适用范围对其未来应用的发展方向进行了讨论。

非张量积双正交小波的构造

从已知一元小波出发借助于方向积分,给出了构造多元非张量积双正交小波的理论与方法,其目的是继承一元优秀小波的性质.由于利用方向积分构造的尺度函数及对偶尺度函数都不是Box样条函数,所以文中构造的小波均不是Box样条小波.

电力电缆护层模型中电感的计算

随着城市的发展,电缆在城市电网中的应用越来越广泛。但由于电缆自身结构与敷设方式的原因,电缆金属护层会产生较高的感应电压,特别在系统不对称时更为显著。为解决这一问题,对正三角形和直线形敷设方式下电缆护层电感进行了分析及建模,该模型对现有的电力电缆护层电感模型做了一定的改进,并采用厂家提供的电缆数值进行计算比对,验证了模型的正确性。

Fast alternating direction method of multipliers for total-variation-based image restoration

A novel algorithm, i.e. the fast alternating direction method of multipliers （ADMM）, is applied to solve the classical total-variation （ TV ）-based model for image reconstruction. First, the TV-based model is reformulated as a linear equality constrained problem where the objective function is separable. Then, by introducing the augmented Lagrangian function, the two variables are alternatively minimized by the Gauss-Seidel idea. Finally, the dual variable is updated. Because the approach makes full use of the special structure of the problem and decomposes the original problem into several low-dimensional sub-problems, the per iteration computational complexity of the approach is dominated by two fast Fourier transforms. Elementary experimental results indicate that the proposed approach is more stable and efficient compared with some state-of-the-art algorithms.

Multi-domain Boundary Element Method with Dissipation

The wave diffraction and radiation around a floating body is considered within the framework of the linear potential theory in a fairly perfect fluid. The fluid domain extended infinitely in the horizontal directions but is limited by the sea bed, the body hull, and the part of the free surface excluding the body waterplane, and is subdivided into two subdomains according to the body geometry. The two subdomains are connected by a control surface in fluid. In each subdomain, the velocity potential is described by using the usual boundary integral representation involving Green functions. The boundary integral equations are then established by satisfying the boundary conditions and the continuous condition of the potential and the normal derivation across the control surface. This multi-domain boundary element method （MDBEM） is particularly interesting for bodies with a hull form including moonpools to which the usual BEM presents singularities and slow convergence of numerical results. The application of the MDBEM to study the resonant motion of a water column in moonpools shows that the MDBEM provides an efficient and reliable prediction method.

Vector Product and an Integrable Dynamical System

We study an autonomous system of first order ordinary differential equations based on the vector product. We show that the system is completely integrable by constructing the first integrals.The connection with Nambu mechanics is established.The extension to higher dimensions is also discussed.

A Quadrature Approach for N-Collinear Crack Problem in an Orthotropic Strip

This study presents the determination of the stress intensity factors （SIFs） at the edges of the cracks in an elastic strip weakened by N-collinear cracks. The problem of an orthotropic elastic strip is reduced to a system of Cauchy type singular integral equations. The system of singular integral equations is approached by a Quadrature technique. Under two different loading conditions, the results are obtained for the different cases of crack numbers. The resistance of the strip is examined by considering the orthotropic properties of the strip material. Finally, the crack interactions are clarified during the analysis.

Integral Equation Method for Electromagnetic Wave Propagation in Stratified Anisotropic Dielectric-Magnetic Materials

We investigate the propagation of electromagnetic waves in stratified anisotropic dielectric-magnetic materialsusing the integral equation method (IEM).Based on the superposition principle, we use Hertz vector formulations ofradiated fields to study the interaction of wave with matter.We derive in a new way the dispersion relation, Snell's lawand reflection/transmission coefficients by self-consistent analyses.Moreover, we find two new forms of the generalizedextinction theorem.Applying the IEM, we investigate the wave propagation through a slab and disclose the underlyingphysics, which are further verified by numerical simulations.The results lead to a unified framework of the IEM for thepropagation of wave incident either from a medium or vacuum in stratified dielectric-magnetic materials.

Provenance of the lower Es2 in the Shanghe area of the Huimin sag

The provenance of the lower Es2 in the Shanghe area was determined from an approach incorporating analysis, elemental ratios,paleocurrent direction,the typomorphic characteristics of detritus and the distribution of conglomerate and gritstone in the peripheral basin.Typical elemental ratios characteristic of the sedimentary area were compared with those from the source areas as abstracted from sediments of the Huimin sag using cluster analysis.The results show that the distribution pattern focuses on Mg/Mn,Fe/K,Al/Na,Ba/Mn and Al/Mg.Mg/Mn is the highest ratio,from 25 to 45.This is similar to the pattern from the Precambrian.Furthermore,paleocurrent direction was used to determine provenance by examining the distribution of gritstone and the seismic progradational reflections.The research results indicate that the provenance is to the northwest in the Precambrian strata where the sand grain size is rough.To the east there is siltstone,fine sandstone and mudstone.This is significant for the exploration of oil and gas within the study area.

Solutions of second order degenerate integro-differential equations in vector-valued function spaces

We study the well-posedness of the second order degenerate integro-differential equations （P2）： （Mu）t＇（t） ＋ a（Mu）＇（t） = Au（t） ＋ ft_c~ a（t - s）Au（s）ds ＋ f（t）, 0 ≤ t ≤ 27r, with periodic boundary conditions Mu（O） = Mu（27r）, （Mu）＇（O） = （Mu）＇（2π）, in periodic Lebesgue-Bochner spaces LP（T,X）, periodic Besov spaces BBp,q（T, X） and periodic Triebel-Lizorkin spaces F~,q（＇F, X）, where A and M are closed linear operators on a Banach space X satisfying D（A） C D（M）, a C LI（R＋） and a is a scalar number. Using known operator- valued Fourier multiplier theorems, we completely characterize the well-posedness of （P2） in the above three function spaces.

BSDEs with Jumps and Path-Dependent Parabolic Integro-differential Equations

This paper deals with backward stochastic differential equations with jumps,whose data(the terminal condition and coefficient) are given functions of jump-diffusion process paths. The author introduces a type of nonlinear path-dependent parabolic integrodifferential equations, and then obtains a new type of nonlinear Feynman-Kac formula related to such BSDEs with jumps under some regularity conditions.

FOUR STEP SCHEME FOR GENERAL MARKOVIAN FORWARD-BACKWARD SDES

This paper studies a class of forward-backward stochastic differential equations (FBSDE)in a general Markovian framework.The forward SDE represents a large class of strong Markov semimartingales,and the backward generator requires only mild regularity assumptions.The authors showthat the Four Step Scheme introduced by Ma,et al.(1994) is still effective in this case.Namely,the authors show that the adapted solution of the FBSDE exists and is unique over any prescribedtime duration;and the backward components can be determined explicitly by the forward componentvia the classical solution to a system of parabolic integro-partial differential equations.An importantconsequence the authors would like to draw from this fact is that,contrary to the general belief,in aMarkovian set-up the martingale representation theorem is no longer the reason for the well-posednessof the FBSDE,but rather a consequence of the existence of the solution of the decoupling integralpartialdifferential equation.Finally,the authors briefly discuss the possibility of reducing the regularityrequirements of the coefficients by using a scheme proposed by F.Delarue (2002) to the current case.

Effect of electromagnetic boundary condition on dynamo actions

In this paper, based on the mean field dynamo theory, the influence of the electromagnetic boundary condition on the dynamo actions driven by the small scale turbulent flows in a cylindrical vessel is investigated by the integral equation approach. The numerical results show that the increase of the electrical conductivity or magnetic permeability of the walls of the cylindrical vessel can reduce the critical magnetic Reynolds number. Furthermore, the critical magnetic Reynolds number is more sensi- tive to the varying electrical conductivity of the end wall or magnetic permeability of the side wall. For the anisotropic dynamo which is the mean field model of the Karlsruhe experiment, when the relative electrical conductivity of the side wall or the rel- ative magnetic permeability of the end wall is less than some critical value, the m=l （m is the azimuthal wave number） mag- netic mode is the dominant mode, otherwise the m=0 mode predominates the excited magnetic field. Therefore, by changing the material of the walls of the cylindrical vessel, one can select the magnetic mode excited by the anisotropic dynamo.