A unified approach for impulsive lag synchronization of chaotic systems with time delay

In this paper, we propose a unified approach for impulsive lag-synchronization of a class of chaotic systems with time delay by employing the stability theory of impulsive delayed differential equations. Three well-known delayed chaotic systems are presented to illustrate our results. Also, the estimates of the stable regions for these systems are given, respectively.     

Linear programming approaches for multicategory support vector machines

We consider linear programming approaches for support vector machines (SVM). The linear programming problems are introduced as an approximation of the quadratic programming problems commonly used in SVM. When we consider the kernel based nonlinear discriminators, the approximation can be viewed as kernel principle component analysis which generates an important subspace from the feature space characterized the kernel function. We show that any data points nonlinearly, and implicitly, projected into the feature space by kernel functions can be approximately expressed as points lying a low dimensional Euclidean space explicitly, which enables us to develop linear programming formulations for nonlinear discriminators. We also introduce linear programming formulations for multicategory classification problems. We show that the same maximal margin principle exploited in SVM can be involved into the linear programming formulations. Moreover, considering the low dimensional feature subspace extraction, we can generate nonlinear multicategory discriminators by solving linear programming problems.Numerical experiments on real world datasets are presented. We show that the fairly low dimensional feature subspace can achieve a reasonable accuracy, and that the linear programming formulations calculate discriminators efficiently. We also discuss a sampling strategy which might be crucial for huge datasets.     

Preparation and optical properties of three-dimensional navel-like Bi2WO6 hierarchical microspheres

Three-dimensional (3D) navel-like Bi₂WO₆ hierarchical microspheres were successfully prepared using a simple hydrothermal method. The 3D navel-like BWO hierarchical structure composed of well-ordered nanosheets displayed the excellent photocatalytic activity, and the degradation rate of norfloxacin was about 67%.     

Synthesis,Crystal Structures and Antioxidant Activities of 1,5-Diketone Derivatives

A new transition-metal-free protocol for the synthesis of polysubstituted 1,5-diketone derivatives from readily available starting materials has been developed. All the compounds were confirmed by HRMS, ~1H NMR and ~(13)C NMR, and the single crystal structure of compound 4 f was determined to be of triclinic system, space group P1 with a = 8.6515(8), b = 8.6694(10), c = 12.4985(8) ?, b = 102.152(6)°, V = 895.43(15) ?~3, D_c = 1.625 g/cm~3, Z = 2, F(000) = 436, m(MoKα) = 1.807 mm~(-1), R = 0.0342 and w R = 0.0691. Furthermore, the result of antioxidation test demonstrated that compound 4 a exhibited better antioxidant activity than butylated hydroxytoluene and vitamin C by the ABTS+ radical cation decolorization assay. In addition, we further studied the mechanism of the transition-metal-free catalytic multicomponent domino reaction.     

单向耦合神经元网络中螺旋波的自发形成机制

构造一个具有单向耦合的二维神经元网络，引入信息传输熵来描述定向信息传输，采用Hindmarsh-Rose神经元模型研究网络中螺旋波等有序波自发产生的机制.数值模拟表明：适当选取耦合的强度和单向耦合的距离，网络可自发出现螺旋波、行波、靶波和平面波.各种有序波的产生与网络中出现信息间歇定向传输有关，网络出现单或多螺旋波时发生熵共振现象.噪声、抑制性耦合和排斥性耦合诱发螺旋波时网络中也存在信息间歇定向传输.首次发现自维持长平面波，其存在是由于网络存在持续的强信息定向传输.     

在全息照相实验中增设光栅辅助白光再现全息图的尝试

针对目前大多数理工科院校开设的全息照相实验中一般只用单色光再现的现状,在保留单色光再现的基础上,增加了光栅辅助白光再现实验内容,丰富了实验内容和提升了实验层次,加深了学生对全息术理论和光栅衍射的理解.     

广义线性模型中检验回归参数统计量的渐近分布

在广义线性模型中,若(对某个α>0),且其它一些正则条件满足,可以证明Wald检验统计量的渐近分布是X2分布,其中,是ZiZi'的最小特征根,Zi是有界的p×q回归系数,yi是q×1响应变量．     

On the propagation of congestion waves in the Internet

Traffic modeling of communication networks such as the Internet has become a very important field of research. A number of interesting phenomena are found in measurements and traffic simulations. One of them is the propagation of congestion waves opposite to the main packet flow direction. The purpose of this paper is to model and analyze packet congestion on a given route and to provide a possible explanation for this phenomenon.