A robust regression approach for spectrophotometric signal analysis

The effectiveness of a regression method strongly depends on the characteristics of the considered regression problem. As a consequence, this makes it difficult to choose a priori the most appropriate algorithm for a given dataset. This issue is faced in this work through a novel regression approach based on the fusion of an ensemble of different regressors. In order to implement the proposed robust multiple system (RMS), four different fusion strategies are explored. In this context, we propose a novel fusion strategy named selection‐based strategy (SBS) that provides as output the estimate obtained by the regression algorithm (included in the ensemble) characterized by the highest expected accuracy in the region of the feature space associated with the considered model. The SBS is based not on a direct combination of the estimates yielded by all the regressors but on a selection mechanism that identifies the expected best available estimate. For such purpose, it exploits the accuracies of the regressors included in the ensemble in different portions of the input feature space. The experimental assessment of the RMS was carried out on three different datasets: a wine, an orange juice, and an apple datasets. The obtained experimental results suggest that, in general, the fusion of an ensemble of different regression algorithms leads to a regression process that is more robust and sometimes also more accurate than traditional regression methods. In particular, the proposed SBS method represents an effective solution to carry out the fusion process. Copyright © 2012 John Wiley & Sons, Ltd.     

Experimental and theoretical analyses of package-on-package structure under three-point bending loading

<正>High density packaging is developing toward miniaturization and integration,which causes many difficulties in designing,manufacturing,and reliability testing.Package-on-Package(PoP) is a promising three-dimensional highdensity packaging method that integrates a chip scale package(CSP) in the top package and a fine-pitch ball grid array (FBGA) in the bottom package.In this paper,in-situ scanning electron microscopy(SEM) observation is carried out to detect the deformation and damage of the PoP structure under three-point bending loading.The results indicate that the cracks occur in the die of the top package,then cause the crack deflection and bridging in the die attaching layer.Furthermore,the mechanical principles are used to analyse the cracking process of the PoP structure based on the multi-layer laminating hypothesis and the theoretical analysis results are found to be in good agreement with the experimental results.     

多层隔热材料飞行试验研究综述

考虑在低地球轨道中热控材料的性能变化直接影响航天器的温度,本文从3个方面研究了多层隔热组件的在轨性能变化。首先,介绍了地面模拟空间环境对热控材料的破坏试验;然后,重点对比分析了哈勃望远镜、长期暴露装置和国际空间站上多层隔热组件样本的试验数据,得到了相关的材料性能结果;最后,详细描述了哈勃望远镜维修用多层隔热组件面膜的地面筛选试验。通过对比在轨飞行数据和地面试验数据发现,影响近地轨道卫星多层隔热组件面膜寿命的首要因素是原子氧和温度循环的共同作用,紫外照射和带电粒子的影响相对较弱。该结论为地面加速试验的规划与修正和长寿命航天器的热设计提供了参考依据。     

Asymptotic behavior of solutions of a free boundary problem modeling multi-layer tumor growth in presence of inhibitor

In this paper we study well-posedness and asymptotic behavior of solution of a free boundary problem modeling the growth of multi-layer tumors under the action of an external inhibitor. We first prove that this problem is locally well-posed in little Hölder spaces. Next we investigate asymptotic behavior of the solution. By computing the spectrum of the linearized problem and using the linearized stability theorem, we give the rigorous analysis of stability and instability of all stationary flat solutions under the non-flat perturbations. The method used in proving these results is first to reduce the free boundary problem to a differential equation in a Banach space, and next use the abstract well-posedness and geometric theory for parabolic differential equations in Banach spaces to make the analysis.     

基于严格耦合波理论的宽光谱金属介质膜光栅衍射特性分析

基于严格耦合波理论建立了金属介质膜光栅的衍射机理模型,给出了TE模式金属介质膜光栅衍射效率的表达式.以-1级衍射效率和工作带宽为评价函数,对金属介质膜光栅的表面浮雕结构进行了优化设计.对于800 nm和1053 nm为中心的TE波,设计的金属介质膜光栅-1级衍射效率优于97%的工作带宽分别达到130 nm和150 nm,最后讨论了设计的宽光谱高衍射效率金属介质膜光栅的制备工艺容差.此研究对于提高脉宽压缩光栅的性能具有重要的意义. 关键词： 衍射效率 金属介质膜光栅 严格耦合波理论     

An Analytical Solution to the One-Dimensional Solute Advection-Dispersion Equation in Multi-Layer Porous Media

An analytical solution to the one-dimensional solute advection-dispersion equation in multi-layer porous media is derived using a generalized integral transform method. The solution was derived under conditions of steady-state flow and arbitrary initial and inlet boundary conditions. The results obtained by this solution agree well with the results obtained by numerically inverting Laplace transform-generated solutions previously published in the literature. The analytical solution presented in this paper provides more flexibility with regard to the inlet conditions. The numerical evaluation of eigenvalues and matrix exponentials required in this solution technique can be accurately and efficiently computed using the sign-count method and eigenvalue evaluation methods commonly available. The illustrative calculations presented herein have shown how an analytical solution can provide insight into contaminant distribution and breakthrough in transport through well defined layered column systems. We also note that the method described here is readily adaptable to two and three-dimensional transport problems.     

带阈值的模糊感知器的收敛性

1 前言各种神经网络被广泛用来解决有导师分类问题．对于模糊感知器,文献[1]提出一种新的训练算法,并证明当样本可分时,该算法有限收敛．文献[2]在模糊神经元中加入阈值 v∈[0,1]．对某些模糊神经网络学习算法如FBP(见文献[3]),阈值在收敛性证明中起着重要的作用．那么,在模糊感知器中加入阈值是否还能得到算法的收敛性?本文将对这个问题进行讨论．     

多层介质的发汗冷却自适应控制

针对一维固定边界复合介质发汗冷却系统的自适应控制问题 ;给出了一个根据实际观测 .基于对气动加热面边界热流密度的估算 ,由热平衡方程及热阻滞函数的特征确定控制输入的自校正控制方法 .理论和数据试验显示 ,对时变的热流及未知的热阻滞函数 ,此方法可以取得很好的控制效果 .     

一种基于后验概率差值的拒识算法

本文提出了一种孤立词语音识别系统中基于后验概率差值的拒识算法。研究了作为拒识特征时，输入词的后验概率和后验概率差值之间的区别，并将多层感知人工神经网络用于拒识特征的学习。相比现存的几种拒识算法，本算法几乎不需要额外的计算和存储量。当识别率为98．2％时，拒识率达到了95．4％。     

Optical Pickup with a Spherical Aberration Compensator Using a Crossed-Stripe Liquid Crystal Device

To increase recording density in an optical disk system, a two-lens system which enlarge its numerical aperture (NA) has been developed. When NA becomes larger, however, the spherical aberration due to disk thickness error increases. We propose an optical pickup with a spherical aberration compensator using nematic liquid crystal (LC). Our LC device is composed of two LC cells each of which has X and Y stripe electrodes, respectively. We discussed how the spherical aberration due to the disk thickness error can be compensated by combination of two crossed cylindrical phase distributions induced by the LC cells, and confirmed the compensation effect in a design example by simulation. We have also fabricated the crossed stripe LC device actually, and have obtained the experimental result which shows that amount sufficient to compensate the aberration is achieved.