一种云样本的控制产生及在电路故障诊断中的应用

为了选择电路故障诊断中的特征样本,提出了产生云样本的方法,并用于神经网络的训练和识别.首先采用逆向云理论对初始特征样本进行统计以获取数字特征,其次采用正向云理论产生扩展训练样本,并用新产生的样本训练两种神经网络.仿真结果表明,采用云样本训练的神经网络要比采用常规样本训练的性能稳健,具有较好的抗噪卢性能,在模拟电路故障诊断中达到了较好的诊断效果.     

基于基因库的新型检测器生成方法

提出一种新的检测器生成方法。由于非我样本中存在着关于非我空间的信息,提出通过统计非我样本中各属性的分布情况来构建基因库,并应用基因库来生成检测器的方法来检测入侵。应用KDDCup1999数据集,通过实验证明该方法能够生成检测率更高的检测器集。     

基于多元回归算法的PaaS平台资源自动化分配方法

针对PaaS平台下资源离散性过强、数据量过大导致的分配不均问题,提出了一种基于多元回归的自动化分配算法实现有效解决。统计所有资源数据样本,利用多元回归算法计算观测序列中残差平方和最小的样本集,代入损失函数中求出损失差值,得到最小损失值,根据梯度下降规律寻找集合中梯度值最优样本,以该样本作为分配参照。设立一套内容为分配与参考样本值相关度最高的资源数据约束条件,不断迭代计算直至求得所有符合约束条件的资源,将符合条件的为一组分配,剩余为另一组分配。根据资源的时间和位数的分布序列,不断实施离散捕捉查找残留资源,再实施二次分配。仿真实验证明,所提方法分配后PaaS平台资源吞吐量增加,消耗代价减少,算法分配时间较低,整体实用能力强。     

物理域中针对人脸识别系统的对抗样本攻击方法

对抗样本攻击揭示了人脸识别系统可能存在不安全性和被攻击的方式。现有针对人脸识别系统的对抗样本攻击大多在数字域进行,然而从最近文献检索的结果来看,越来越多的研究开始关注如何能把带有对抗扰动的实物添加到人脸及其周边区域上,如眼镜、贴纸、帽子等,以实现物理域的对抗攻击。这类新型的对抗样本攻击能够轻易突破市面上现有绝大部分人脸活体检测方法的拦截,直接影响人脸识别系统的结果。尽管已有不少文献提出数字域的对抗攻击方法,但在物理域中复现对抗样本的生成并不容易且成本高昂。本文提出一种可从数字域方便地推广到物理域的对抗样本生成方法,通过在原始人脸样本中添加特定形状的对抗扰动来攻击人脸识别系统,达到误导或扮演攻击的目的。主要贡献包括:利用人脸关键点根据脸型构建特定形状掩膜来生成对抗扰动;设计对抗损失函数,通过训练生成器实现在数字域的对抗样本生成;设计打印分数损失函数,减小打印色差,在物理域复现对抗样本的生成,并通过模拟眼镜佩戴、真实场景光照变化等方式增强样本,改善质量。实验结果表明,所生成的对抗样本不仅能在数字域以高成功率攻破典型人脸识别系统VGGFace10,且可方便、大量地在物理域复现。本文方法揭示了人脸识别系统的潜在安全风险,为设计人脸识别系统的防御体系提供了很好的帮助。     

Gold immunochromatographic sensor for the rapid detection of twenty-six sulfonamides in foods

A gold immunochromatographic sensor (GICS) was developed for the rapid detection of 26 sulfonamides in honey samples.The sensor was based on a group-specific monoclonal antibody (mAb) that can recognize all 26 sulfonamides.Three haptens (hapten 1 with a thiazole ring,hapten 2 with a benzene ring,and hapten 3 with a straight carbon chain) were used for antigen preparation.With hybridoma technology,a group-specific mAb was screened with a 50％ maximal inhibitory concentration (IC50) against sulfathizole (STZ) and the other 25 analogues ranging from 0.08 to 90.18 ng/mL.Mono-dispersed gold nanoparticles were conjugated with the mAb to develop the lateral immunochromatographic strip.A labeled antibody concentration of 0.1 μg/mL and a coating antigen concentration of 0.2 μg/mL in the test line were chosen for strip preparation.Under optimized conditions,the visual limits of detection (vLOD) for the concentrations of STZ,sulfamethoxazole,sulfamethizole,sulfadiazine,sulfamerazine,sulfadimethoxine,sulfamonomethoxine,sulfameter,sulfamethoxypyridazine,and sulfachloropyridazine were 5,0.25,0.25,10,5,10,25,2.5,5,0.25,and 10 μg/kg,respectively.Scanner analysis in honey samples revealed good performance for detection of the 26 sulfonamides.Commercial honey samples were tested with the sensor and positive results were confirmed with high-performance liquid chromatography.The proposed strip sensor provides a convenient method for the rapid and reliable determination of sulfonamides pollutants in honey samples.     

聚碳酸酯基聚氨酯/芳纶纤维复合材料的制备与性能

以聚碳酸酯二元醇为软段,利用预聚体法制备了系列聚碳酸酯基聚氨酯/芳纶浆粕纤维(Aramid pulp)复合材料,研究了芳纶浆粕纤维对聚碳酸酯基聚氨酯弹性体(PUE)力学性能的影响。采用扫描电镜、X射线衍射、差示扫描量热分析、热重分析、红外光谱及电子拉伸机等测试仪器对聚氨酯复合材料的结构与性能进行了表征和分析。结果表明,芳纶浆粕纤维能有效实现对聚氨酯弹性体的增强作用,其中对撕裂强度的增强尤为突出。当芳纶浆粕纤维用量为0.5%时,复合材料的撕裂强度由106 k N/m提高到120 k N/m,表现出最好的力学性能;芳纶浆粕纤维在聚氨酯中分散均匀,提高了复合材料的热稳定性。     

Semisupervised dimensionality reduction for hyperspectral images based on the combination of semisupervised learning and metric learning

This paper presents a semisupervised dimensionality reduction (DR) method based on the combination of semisupervised learning (SSL) and metric learning (ML) (CSSLML-DR) in order to overcome some existing limitations in HSIs analysis. Specifically, CSSML focuses on the difficulties of high dimensionality of hyperspectral images (HSIs) data, the insufficient number of labelled samples and inappropriate distance metric. CSSLML aims to learn a local metrics under which the similar samples are pushed as close as possible, and simultaneously, the different samples are pulled away as far as possible. CSSLML constructs two local-reweighted dynamic graphs in an iterative two-steps approach: L-step and V-step. In L-step, the local between-class and within-class graphs are updated. In V-step, the transformation matrix and the reduced space are updated. The algorithm is repeated until a stopping criterion is satisfied. Experimental results on two well-known hyperspectral image data sets demonstrate the superiority of CSSLML algorithm compared to some traditional DR methods.     

一种纸浆模塑蜂窝板材缓冲性能的研究

目的 为了解决因技术水平制约,纸蜂窝材料芯纸构型单一、单层厚度受限等瓶颈问题,开发一种通用型缓冲结构板材。方法 以纸浆模塑为原材料,以六棱柱结构为例,设计并加工出一种通过正反插方式组合而成的蜂窝板材,并采用有限元方法进行仿真,得到关键结构参数和相关最优参数组合。结果 正反插结构的纸浆模塑板材具有较好的耦合效应,承载能力相较于单层板材大幅提高;结合极限载荷、比吸能等评价指标对板材性能进行定量分析,初始压缩载荷最大可达到73.7kN,满足托盘等重型包装器具的承载需求。通过极差和方差分析可知,各结构参数对板材承载性能和缓冲性能的影响程度,研究表明单元壁厚、中截面边长对该板材承载性能和缓冲性能影响显著。结论 正反插结构解决了现有纸蜂窝材料高度、厚度受限,构型单一等瓶颈问题,提高了纸浆模塑蜂窝板材的承载性能和缓冲性能,可以满足重载要求。与之相关的其他正多边形锥形薄壁管单元亦可以使用同样的正反插设计理念和研究方法。     

New aspects in the microstructure of YBCO melt-textured high-Tc superconductors

The microstructure and phase constitution of bulk textured YBCO samples prepared by the modified MTG method in the longitudinal temperature gradient have been investigated. We found the existence of an unusual phase between stacked platelets. Microanalysis shows that this phase may be characterized as Y-143. This phase forms ellipsoid-like particles with a typical size about 0.05–2 which can play the role of effective pinning centers. The reason for the phase formation is discussed. We assume that this phase exists commonly in melt-textured samples prepared in the temperature field gradient.     

2010年我国恶意代码新特点的研究

文章以公安部2010年计算机病毒疫情调查活动的数据作为基础,以国家计算机病毒应急处理中心国家级恶意代码样本库作为支撑,结合信息网络安全通报机制成员单位汇总的情况和各反病毒研究机构发布的安全报告,阐述了2010年我国恶意代码发展的总体情况,分析了2010年我国恶意代码出现的新特点,探索了今后恶意代码的发展趋势并提出对策建议。