A Blind Watermarking Algorithm Resisting to Geometric Transforms Based on SVD

A new watermarking algorithm resisting to geometric transformation based on singular value decomposition(SVD) in logarithm polar coordinate is proposed.The log-polar mapping(LPM) is used to resist rotation and scaling attacks,and the odd-even quantization algorithm is used to embed watermark so it can be extracted without the original host image.The experiments show that the proposed algorithm not only resists various geometric attacks but also is robust enough to the common signal processing.     

A Direct Spectral Collocation Poisson Solver in Polar and Cylindrical Coordinates

In this paper, we present a direct spectral collocation method for the solution of the Poisson equation in polar and cylindrical coordinates. The solver is applied to the Poisson equations for several different domains including a part of a disk, an annulus, a unit disk, and a cylinder. Unlike other Poisson solvers for geometries such as unit disks and cylinders, no pole condition is involved for the present solver. The method is easy to implement, fast, and gives spectral accuracy. We also use the weighted interpolation technique and nonclassical collocation points to improve the convergence.     

三斜晶体介质中三维平面波的反射

讨论三斜晶体介质半空间应力自由边界处三维平面波的传播.给出了1个寻找三维准P(qP)、准SV(qSV)和准SH(qSH)波的所有3个相速度解析表达式的方法.得出了三斜介质中qP、qSV、qSH波反射系数振幅比的三维闭式解,将其用于研究不同入射角时,对应的反射系数的数值变化,给出了不同极角和方位角时的图示.最后通过数值实例表明,与二维的情况相比较,三维各向异性对反射系数的影响更明显.     

Extended Thorin classes and stochastic integrals

Extended Thorin classes T ^ϰ (R ^d ), ϰ > 0, of infinitely divisible probability laws on R ^d are defined and analytically characterized in [6]. Using general results from [8] and [9], in this paper, we derive a stochastic integral representation of these classes. Published in Lietuvos Matematikos Rinkinys, Vol. 47, No. 4, pp. 497–503, October–December, 2007.     

球面上Poisson方程的两子域加性Schwarz算法

研究求解球面上的Poisson方程的加性Schwarz算法。对于两子域加性Schwarz算法,通过选取最优参数得到子域内边界上的优化传输条件,由此得到的最优加性算法可大大加快收敛的速度;而且,算法具有有限步收敛性。     

Conformation‐Dependent Sequence Design of HP Copolymers: An Algorithm Based on Sequential Modifications of Monomer Units

We present a new modification of the so‐called conformation‐dependent sequence design scheme for HP copolymers which was proposed several years ago (H and P refer to the hydrophobic and polar monomer units, respectively). New method models the real chemical experiments more realistically. We performed Monte Carlo computer simulations using the bond‐fluctuation model for protein‐like copolymers obtained by means of the new “iterative” method and compared the results with those obtained for originally proposed “instantaneous coloring” procedure. Copolymers designed by the “iterative” method are shown to have better‐optimized functional properties. The investigation of the influence of sequence preparation conditions has revealed that the statistical properties of designed HP sequences depend rather strongly on the density of the parent homopolymer globule but not on the composition of H and P units.     

极地平流层云及其非均相化学

南极臭氧洞的形成与南极平流层云及其非均相化学过程有很大关系.南极平流层云中存在着硫酸气溶胶粒子、与硫酸/硝酸/水有关的固体或液体粒子以及水的冰晶粒子等,在其表面上可以发生非均相化学反应,一方面使本来比较惰性的硝酸氯(ClONO₂)具有相当大的活性,另一方面可以把NO₂或硝酸以硝酸固体粒子的形式从平流层中移走.由非均相化学产生的HOCl和Cl₂发生光离解,产生活性氯,加强了与ClO的二聚物或者与ClO-BrO互反应有关的破坏臭氧的催化循环圈的进行,加快南极臭氧洞的形成.本文重点介绍极地平流层云及其非均相化学在极地平流层臭氧消耗过程中的作用,使人们对加重平流层臭氧消耗的非均相化学有所了解。     

各向异性磁介质毕奥-萨伐尔定律极坐标形式

给出磁各向异性介质中的毕奥-萨伐尔定律的极坐标形式.据此,可求出若干电流按曲线方程r=r(θ)分布的极坐标极点处的磁场,比用定律的笛卡儿坐标形式求解来得简便.     

从分子中正电荷分数探讨常用溶剂的极性顺序

基于桑德逊电负性均衡原理,改进了计算方法,计算出溶剂分子中的正电荷分数,得到的常用溶剂极性顺序与实测顺序基本一致。改进的计算方法比受溶剂纯度等条件影响的实际测量更通用,并有一定的预见性。