Variable step-size affine projection algorithm based on global speech absence probability for adaptive feedback cancellation

A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current frame.The weight vector of the adaptive filter is updated by the probability of the speech absence.The performance measure of acoustic feedback cancellation is evaluated using normalized misalignment.Experimental results demonstrate that the proposed approach has better performance than the normalized least mean square(NLMS) and the constant step-size affine projection algorithms.

利用HyperChem获取反应过渡态的方法

利用HyperChem的动态数据交换DDE(Dynamic Data Exchange)功能,通过Excel中的Visual BasicA编程来控制Hy-perChem的运行,从而控制反应过程中的反应坐标和反应步长,计算得到反应系统沿反应坐标的能量变化曲线,从而可获取反应的过渡态和活化能△E。利用该计算方法搜寻了喹啉分子在S-Mo-Ni催化剂晶体表面催化加氢反应的过渡态,取得较好的效果。利用该方法可以确定复杂反应过渡态,从而为实验研究起理论指导作用。