基于粒子滤波的多区域辨识性建模跟踪算法

为使跟踪算法中的目标模型不被相同特征的背景像素所干扰,在粒子滤波的框架下引入多区域辨识性建模机制,提出1种新的鲁棒的目标跟踪算法。提出的算法侧重能够辨识前景与背景的最有效信息,把目标物体划分为多个子区域。通过统计子区域与背景类别的类内/类间特性选择出最具信息量的子区域。在选出的目标区域基础上,提出的算法以贝叶斯的方式同时考虑图像信息及空间信息,建立具有辨识性的目标表观模型,并在粒子滤波的更新阶段用以估量目标的所在区域。在一系列具有挑战性的视频序列上的实验结果证明了,在许多复杂场景下,提出的方法与传统的粒子滤波跟踪器相比的鲁棒性以及有效性。     

基于Jack的虚拟环境中一种防止穿越的实现

在虚拟环境下虚拟人手和虚拟物体的交互中,会发生穿越现象。为了解决穿越问题,在人体模型系统Jack的虚拟环境中,根据约束Constraint对象的特点,利用Constraint对象来模拟物体对人手阻挡作用,并利用约束队列实现了对场景中Constraint对象的管理,达到防穿越的效果。     

基于Widrow-Hoff神经网络的多指标推荐算法

为解决传统的协同过滤推荐算法不能综合运用多个指标进行推荐的问题,通过引入多指标评分的概念对标准的协同过滤推荐算法进行扩展,提出一种基于Widrow-Hoff神经网络的多指标推荐算法。利用Widrow-Hoff最小二乘法自适应算法在进行系统辨识时的高精度拟合特性,提出一种基于Widrow-Hoff最小二乘法算法的用户偏好特征向量计算方法。利用用户偏好特征向量和空间距离矩阵度量用户相似度,以定位邻居集并为用户推荐最优项目。实验结果表明,本文算法可提高推荐精度,改进推荐质量。     

Biomimetic micropatterning of silica by surface-initiated polymerization and microcontact printing

Micropatterns of silica on a gold substrate were generated by a biomimetic approach, namely, the biosilicification of silicic acids. The procedure consists of three simple steps: pattern generation of a polymerization initiator, (BrC(CH(3))(2)COO(CH(2))(11)S)(2), by microcontact printing; surface-initiated, atom-transfer radical polymerization of 2-(dimethylamino)ethyl methacrylate (DMAEMA) from the patterned area; and polycondensation of silicic acids. The tertiary amine-containing polymer, pDMAEMA, aided in the spatially controlled polycondensation of silicic acids on surfaces in the presence of phosphate ions, and micropatterns of silica on a gold substrate were successfully generated in combination with the technique of microcontact printing. The procedure could be extended to the controlled fabrication of silica patterns with any size, shape, or thickness.     

Advances in Soft Materials for Sustainable Electronics

In the current shift from conventional fossil-fuel-based materials to renewable energy,ecofriendly mate-rials have attracted extensive research interest due to ...     

An efficient second‐order characteristic finite element method for non‐linear aerosol dynamic equations

In the paper we consider the non‐linear aerosol dynamic equation on time and particle size, which contains the advection process of condensation growth and the process of non‐linear coagulation. We develop an efficient second‐order characteristic finite element method for solving the problem. A high accurate characteristic method is proposed to treat the condensation advection while a second‐order extrapolation along the characteristics is proposed to approximate the non‐linear coagulation. The method has second‐order accuracy in time and the optimal‐order accuracy of finite element spaces in particle size, which improves the first‐order accuracy in time of the classical characteristic method. Numerical experiments show the efficient performance of our method for problems of log‐normal distribution aerosols in both the Euler coordinates and the logarithmic coordinates. Copyright © 2009 John Wiley & Sons, Ltd.     

Selective Coloration of Melanin Nanospheres through Resonant Mie Scattering

Black melanin inks are prepared to selectively exhibit colors under strong light, inspired by human hair. High absorbance of melanin suppresses multiple scattering, causing resonant Mie scattering predominant. Various colors can be developed as the resonant wavelength dictated by nanosphere diameter. Therefore, the melanin inks can be used to encrypt and selectively disclose multicolor patterns for anticounterfeiting applications.     

异步电机电磁振动研究综述

异步电动机是将电能转化为机械功的关重设备,在工业和人类生活中有着极为广泛的应用。振动作为电能-机械能转换不可避免的环节,其影响了能量转换的效率以及设备的安全性、可靠性,一般对振动问题的总结与描述从故障诊断的角度进行了分析研究较多,而从振动产生机理及动力学的方面进行论述却很少。综述力求以动力学(激励源)研究为基础,力求搭建异步电机电磁振动系统性的分析途径与方法,以帮助工程技术人员掌握异步电机电磁振动理论的进展并为深入研究提供借鉴。首先介绍了电机中电磁振动的来源,包括机械因素和电磁因素。并介绍电磁振动分析的理论方法。     

超高效液相色谱串联质谱法测定牛奶中三氮脒残留

目的 本研究旨在结合超高效液相色谱－串联质谱(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)技术,建立简便、快速的样品前处理方法,对牛奶中的痕量三氮脒残留进行检测。方法 用1%乙酸乙腈溶液振荡提取后,在-4℃条件下高速离心,取上清液旋转蒸干后,用10%乙腈水溶液复溶,用超高效液相色谱-串联质谱仪在正离子扫描及多反应监测(multiple reaction monitoring, MRM)模式下分析,外标法定量。结果 牛奶中三氮脒的检出限(limit of detection, LOD)为5 μg/kg,定量限(limit of quantification, LOQ)为15 μg/kg,在20~1000 μg/L浓度范围内线性良好,相关系数(r)为0.9993。将所研究的方法应用于实际牛奶样本中,其加标回收率在81.65%至85.49%之间,日内精密度分别在4.5%~5.5%,日间精密度在5.9%~8.2%之间。结论 本方法采用振荡提取加低温高速离心净化的前处理方法,简单快速,结合UPLC-MS/MS,可实现痕量水平残留的高灵敏度检测,适用于快速、高灵敏检测牛奶及其他动物源性食品中的三氮脒残留。