A new algorithm of non-Gaussian component analysis with radial kernel functions

We consider high-dimensional data which contains a linear low-dimensional non-Gaussian structure contaminated with Gaussian noise, and discuss a method to identify this non-Gaussian subspace. For this problem, we provided in our previous work a very general semi-parametric framework called non-Gaussian component analysis (NGCA). NGCA has a uniform probabilistic bound on the error of finding the non-Gaussian components and within this framework, we presented an efficient NGCA algorithm called Multi-index Projection Pursuit. The algorithm is justified as an extension of the ordinary projection pursuit (PP) methods and is shown to outperform PP particularly when the data has complicated non-Gaussian structure. However, it turns out that multi-index PP is not optimal in the context of NGCA. In this article, we therefore develop an alternative algorithm called iterative metric adaptation for radial kernel functions (IMAK), which is theoretically better justifiable within the NGCA framework. We demonstrate that the new algorithm tends to outperform existing methods through numerical examples.     

线性规划Karmarkar算法的一种改进算法及其数值检验

本文给出求解线性规划问题的一种改进的Karmarkar算法IKA.本算法通过施行仿射变换,将已给定的一个可行内点,变成另一空间可行域中所有分量为1的点e,然后从e出发,沿梯度方向进行一维搜索,使问题的目标函数单调下降,并收敛于最优值,因而不需假定目标函数最优值为已知.几个有数百个约束方程和变量的实际算例表明本算法比Karmarkar算法有效.     

Characterization of a dual wavelength fibre laser based-on dumbbell configuration

This paper reports the design of a dual wavelength fibre laser system using a dumbbell shaped configuration. The oscillation of the lasing wavelength is completed via fibre loop mirrors with a tuneable bandpass filter. The output power, side mode suppression ratio and wavelength spacing of the lasers were investigated against the pump power for forward and backward pumping schemes. The output powers of 4.99 and 3.69 dBm at 1545.08 and 1547.28 nm, respectively, for forward pumping scheme. On contrary, the output powers of 1.93 and 2.14 dBm at 1546.12 and 1551.48 nm, respectively, for backward pumping scheme. The peak output powers of less than 1 dB difference are obtained without any adjustment of the intra-cavity loss over a wider spectral range.     

A linear Bragg–Fresnel optics fabricated for 1D focusing of 18 nm X-ray radiation

The theoretical and technique results of a 1D focusing linear Bragg–Fresnel optics working at 18 nm X-ray radiation are given in the present paper. A theoretical method describing its optical performances is introduced briefly, the parameters of the diffraction pattern are presented. The preparation of multilayer mirrors, the decision of X-ray absorber layer thickness and the fabrication process of the diffraction pattern are described. The studied results of thermal and chemical stabilities for Mo/Si multilayer structure are shown. Some measured results for the 1D focusing linear Bragg–Fresnel optics are given.     

A fundamental relationship between the relaxation spectra and the tangent distribution function in the theory of linear viscoelasticity

The tangent distribution function (TDF) is analyzed within the theory of linear viscoelasticity on mechanical properties. A proof is given that both the relaxation and retardation spectra can be derived from the TDF, through a Fredholm integral equation. Furthermore, the relaxation strength can be calculated as a consequence of this relationship. Finally, as an example, the relationship is applied to discrete spectra.     

12 MeV直线感应加速器主开关的优化设计

 介绍了12MeV直线感应加速器主开关的一种优化设计。在保持原有主开关的设计风格和接口结构的条件下，通过优化设计局部结构和调整开关电极尺寸，把主开关的结构电感从63.7nH减小到35nH，使得加速腔的高压脉冲前沿从39.6ns减小到27ns，从而有利于提高12MeV直线感应加速器的性能，验证了优化设计的可行性。     

Physics possibilities at a linear collider

We review some recent studies about the parameter determination of top quarks,W bosons, Higgs bosons, supersymmetric particles and in the ADD model of extra dimensions at a linear collider.     

The simplex method and unrestricted variables

Suppose that the simplex method is applied to a linear programming problem havingm equality constraints andr unrestricted variables. We give a method of performing the steps of the simplex method which reduces the arithmetic operation count byrm at each iteration. This savings in operations is achieved, since the method does not update the rows of the basis inverse associated with the unrestricted variables. Similar computational savings are achieved when the method is applied to the updating of anLU-factorization of the basis matrix.This research was supported by the Natural Sciences and Engineering Research Council of Canada under Grant No. A8189 and by a postgraduate fellowship.     

On a “stability” in the linear complementarity problem

In this work we re-wrote the Linear Complementarity Problem in a formulation based on unknown projector operators. In particular, this formulation allows the introduction of a concept of “stability” that, in a certain way, might explain the way block pivotal algorithm performs.     

线性流形上反对称正交对称矩阵反问题的最小二乘解

该文讨论了线性流形上矩阵方程AX=B反对称正交对称反问题的最小二乘解及其最佳逼近问题．给出了最小二乘问题解集合的表达式，得到了给定矩阵的最佳逼近问题的解，最后给出计算任意矩阵的最佳逼近解的数值方法及算例．