人群运动中的视觉显著性研究

在公共场所中人们都倾向于以分组的形式进行运动,本文把这种以分组形式运动的若干个行人称为运动群组,具有视觉显著性的人群运动群组是场景理解的重点,其对人群的整体运动也影响最大。本文对运动群组的视觉显著性展开了研究,分别从规模、速度、组内紧致度和变化度４个方面来对运动群组的视觉显著性进行度量,并基于该度量给出了视觉显著性运动群组检测方法。首先,利用光流法对运动人群进行分析得到光流向量;然后通过层次聚类算法对运动人群进行分组;最后,基于本文所给出的度量计算每个群组的视觉显著性,以检测出视觉显著性最高的运动群组。实验表明该方法能够有效地对视觉显 著性运动群组进行检测,该研究成果可应用于人群场景理解、人群运动分析和人群场景分类等计算机视觉研究领域。     

结合深度学习与条件随机场的遥感图像分类

目的 为进一步提高遥感影像的分类精度,将卷积神经网络（CNN）与条件随机场（CRF）两个模型结合,提出一种新的分类方法。方法 首先采用CNN对遥感图像进行预分类,并将其类成员概率定义为CRF模型的一阶势函数;然后利用高斯核函数的线性组合定义CRF模型的二阶势函数,用全连接的邻域结构代替常见的4邻域或8邻域;接着加入区域约束,使用Mean-shift分割方法得到超像素,通过计算超像素的后验概率均值修正各像素的分类结果,鼓励连通区域结果的一致性;最后采用平均场近似算法实现整个模型的推断。结果 选用3组高分辨率遥感图像进行地物分类实验。本文方法不仅能抑制更多的分类噪声,同时还可以改善过平滑现象,保护各类地物的边缘信息。实验采用类精度、总体分类精度OA、平均分类精度AA,以及Kappa系数4个指标进行定量分析,与支持向量机（SVM）、CNN和全连接CRF相比,最终获得的各项精度均得到显著提升,其中,AA提高3.28个百分点,OA提高3.22个百分点,Kappa提高5.07个百分点。结论 将CNN与CRF两种模型融合,不仅可以获得像元本质化的特征,而且同时还考虑了图像的空间上下文信息,使分类更加准确,后加入的约束条件还能进一步保留地物目标的局部信息。本文方法适用于遥感图像分类领域,是一种精确有效的分类方法。     

基于LabVIEW的控制阀性能测试评估系统设计

控制阀在工业控制领域扮演十分重要的角色,但目前国内对控制阀性能测试评估系统的研究十分薄弱,并且常规的仪器仪表很难精确测试控制阀的性能;针对这种情况,基于NI compactRIO硬件、各类传感器以及LabVIEW软件开发设计了一套控制阀性能测试评估系统,该系统能实时检测、采集处理数据,能够把阀门性能测试过程中的数据自动保存与分析处理,实现了控制阀的在线测试和功能评估,并且可将控制阀各项性能指标评估结果汇集于一张类似体检单的报表显示,给阀门厂商的出厂测试、维修检测以及日常维护提供参考依据;采用该系统对某公司的直通气开式薄膜调节阀S9044进行了性能测试评估,实验结果表明,该系统能够全面、精确地测试出调节阀的各项性能指标,且系统软件交互界面良好、扩展性强、精度高。     

A shape prior constraint for implicit active contours

We present a shape prior constraint to guide the evolution of implicit active contours. Our method includes three core techniques. Firstly, a rigid registration is introduced, using a line search method within a level set framework. The method automatically finds the time step for the iterative optimization processes. The order for finding the optimal translation, rotation and scale is derived experimentally. Secondly, a single reconstructed shape is created from a shape distribution of a previously acquired learning set. The reconstructed shape is applied to guide the active contour evolution. Thirdly, our method balances the impact of the shape prior versus the image guidance of the active contour. A mixed stopping condition is defined based on the stationarity of the evolving curve and the shape prior constraint. Our method is completely non-parametric and avoids taking linear combinations of non-linear signed distance functions, which would cause problems because distance functions are not closed under linear operations. Experimental results show that our method is able to extract the desired objects in several circumstances, namely when noise is present in the image, when the objects are in slightly different poses and when parts of the object are invisible in the image.     

Optimal combination forecasts for hierarchical time series

In many applications, there are multiple time series that are hierarchically organized and can be aggregated at several different levels in groups based on products, geography or some other features. We call these “hierarchical time series”. They are commonly forecast using either a “bottom-up” or a “top-down” method.In this paper we propose a new approach to hierarchical forecasting which provides optimal forecasts that are better than forecasts produced by either a top-down or a bottom-up approach. Our method is based on independently forecasting all series at all levels of the hierarchy and then using a regression model to optimally combine and reconcile these forecasts. The resulting revised forecasts add up appropriately across the hierarchy, are unbiased and have minimum variance amongst all combination forecasts under some simple assumptions.We show in a simulation study that our method performs well compared to the top-down approach and the bottom-up method. We demonstrate our proposed method by forecasting Australian tourism demand where the data are disaggregated by purpose of travel and geographical region.     

新型核序列自相关函数用于非同源蛋白质结构类预测

从天然氨基酸的50个性质参数中经主成分分析得出1种新的氨基酸描述子:氨基酸特征性质得分.并在此基础上通过定义基于向量形式的自相关函数以及引入Mercer核技术将该函数运算空间进行非线性变换,最终提出了1种新的蛋白质序列表征方法:核序列自相关函数.采用该函数对632个已知晶体结构的非同源蛋白分类研究结果表明:KSACF能...     

光纤法珀应变传感器波长检测量化误差理论分析

介绍了光纤法珀应变传感器的基本原理,通过钢衍梁连续加载实验发现了应变误差有规律的跳动现象,并在误差理论的基础上深入分析了影响传感器精度的因素,提出了光探测器件本身波长感知的不连续性是造成传感器误差的重要原因,并对此进行了实验仿真,验证了我们的分析,对于进一步提高传感器的精度有较强的实际意义。     

RAID系统的结构化模型、

分析RAID系统组成,按功能分成target,内存管理,RAID管理和initiator四个部分,对各个部分的功能简单说明。     

飞行指挥模拟器的飞行指挥训练方程的设计

介绍了飞行指挥模拟器的起落方程、飞行空中方程和特情调度方程等的设计与求解方法,该方法实现了对各种飞行情况的习行指挥调度训练的评分与打印。实际运行结果表明,本文介绍了方法具有飞行指挥调度训练灵活、训练评分准确有效、训练员操作简便以及用户界面友好等优点。     

Synthesis of bio-functionalized copolymer particles bearing carboxyl groups via a microfluidic device

Monodisperse copolymer particles carrying surface carboxyl groups in the range of 50–200 μm were prepared by in situ UV polymerization of ethyleneglycol dimethacrylate (EGDMA) with acrylic acid (AA) via a microfluidic flow-focusing device (MFFD). The design of the coaxial orifices in the MFFD enables the confinement of the comonomer liquid thread to the central axis of the microchannel, which can avoid the wetting problem of comonomer liquid with the microchannel and can successfully produce monodisperse copolymer microspheres with coefficient of variance below 5%. The effects of concentration of EGDMA and AA on droplet diameters and the distribution of carboxyl group on particle surfaces were examined. It has been found that, increasing the concentration of AA would decrease particle sizes, but increase the distribution of carboxyl group on particle surfaces. Bioconjugation of the carboxylated copolymer particles with the anti-rabbit IgG–Cy3 conjugates was successfully demonstrated. By increasing the concentration of AA accompanied with decreasing the particle sizes, high efficiency of bioconjugation on carboxylated copolymer particles was achieved. The rapid continuous synthesis of carboxylated copolymer particles via a microfluidic device provides a reliable control of particle sizes and composition for massive production in biotechnological applications.