一种快速核密度估计背景建模方法

针对核密度估计背景建模方法运算量大难以实时应用的问题,提出了一种基于背景直方图分布的快速核密度估计背景建模方法。选用三角核函数进行核密度估计,根据三角核带宽函数的截断效应,引入背景分布的直方图完成快速背景建模,在保证目标检测准确性的同时提高运算速度。测试实验结果验证了算法能够满足监控系统的实时性要求。     

组合核支持向量机的模式分析新方法

基于支持向量机核函数的条件,将Sobolev Hilbert空间的再生核函数和多项式核函数进行有效的线性组合,给出一种新的支持向量机的组合核函数,提出一种基于再生核的组合核函数支持向量机的模式分析方法,该方法兼具了全局核函数与局部核函数的优点,且算法的复杂度被降低。仿真实验结果表明：支持向量机的核函数采用基于再生核的组合核函数是可行的,且此核函数不仅具有核函数的非线性映射特征,而且也继承了核函数对非线性逐级精细逼近的特征,模式分析的效果比单核函数可以更加细腻。     

基于核密度估计的三维非等距模型簇的对应关系计算方法

针对三维非等距模型簇的一致对应关系计算问题,提出了一种基于核密度估计的三维非等距模型簇对应关系计算方法.首先引入离散时间演化过程描述符(DEP)提取三维模型表面的特征描述符,得到不同区域的不同分布特征;其次通过核密度估计建立非等距模型间的映射关系;最后利用弹性网罚函数对非等距模型簇映射关系进行凸优化,从而得到更准确的三维非等距模型簇点到点对应关系.实验结果表明,利用时变描述符与核密度估计相结合的方法计算非等距模型簇的对应关系,在一定程度上减小了模型簇一致对应的测地错误,与Aubry的算法比较,测地错误平均下降至0.054.该基于核密度估计的匹配算法与使用函数映射或随机森林函数的方法相比,能构建出更为准确的非等距模型簇一致对应关系.     

核密度估计及其在聚类算法构造中的应用

经典数理统计学中的核密度估计理论是构造基于数据集密度函数聚类算法的理论基础，采用分箱近似的快速核密度函数估计方法同样为构造高效的聚类算法提供了依据．通过对核密度估计理论及其快速分箱核近似方法的讨论，给出分箱近似密度估计相对于核密度估计的均方误差界，提出基于网格数据重心的分箱核近似方法．在不改变计算复杂度的条件下，基于网格数据重心的分箱核近似密度函数计算可以有效地降低近似误差，这一思想方法对于构造高效大规模数据聚类分析算法具有指导意义．揭示了基于网格上密度函数近似的聚类算法与核密度估计理论之间的关系．     

针对不平衡数据的改进的近邻分类算法

针对不平衡数据分类问题,一种基于密度的近邻分类算法（DNN）被提出。它利用核密度估计敏锐地捕捉不平衡数据的局部分布特征,由此产生更好的分类结果。用核密度估计方法估计查询实例的各类别密度,以此对其进行密度定位;将原始数据空间中的点映射到由类别密度和距离信息构成的空间;在这个映射空间中动态地选择近邻并对查询实例进行分类。实验结果表明,DNN算法在15个不平衡数据集上分类性能良好。     

改进的核密度点云去噪算法的研究与实现

针对目前基于核密度估计的去噪算法在核函数参数的选取上未能充分体现散乱点云数据的表面特征,提出一种改进的去噪算法。以当前点法向量与其邻域内点的法向量构造的差向量作为核函数的参数,引入面积权重进行光顺,通过构造空间单元格的最大连通域剔除离群点,结合K-近邻搜索建立点云之间的拓扑关系,以改进的高斯函数作为核函数计算当前点的影响值。实验结果表明,该算法在有效去除表面噪声和离群点的同时,能够较好保留模型的细节特征。     

核密度估计在立体匹配中的应用

提出了一种基于核密度估计相似性测度的立体匹配方法。将匹配基元中对应像素点的颜色差值在差值特征空间中进行核密度估计,并以此作为相似性测度。在此基础上建立全局能量函数,并采用改进的置信度传播算法进行视差图的求解。实验结果证明该相似性测度较传统方法有明显的改进。     

立体视觉中基本矩阵的改进投影M估计方法

在立体视觉与图像运动分析中，需要排除特征误配点的影响进而得到精确的基本矩阵估计。针对EIV(Error In Variables)模型中基于投影的M估计方法存在的核密度估计和正常点与异常点阈值确定的局限性，提出一种改进的投影M估计算法：首先给出新的用于搜索极值点的自适应核密度估计函数，然后改进了正常点的确定方法。对模拟及真实数据进行了实验，验证了改进投影M估计方法的有效性及稳健性。     

基于点密度加权的多尺度分层点云识别网络

与密集且规则分布的2D栅格状图像不同,3D点云是不规则且无序的,对其进行卷积可能会存在一定的困难,因此,提出了一种针对原始3D点云的卷积运算。该方法使用高斯核密度估计和多层感知器（multi-layer perceptron,MLP）网络来学习密度函数,将学习到的点的密度尺度结合点的相对位置,通过由MLP网络近似的权重函数之中,得到局域中每个点的权重值。整个卷积核可视为由权重函数和密度函数组成的3D点局域坐标的非线性函数,可用于对3D空间中任意点集进行平移不变和置换不变的卷积,并融合多尺度采样分组和法向特征使网络达到最佳效果。在ModelNet40和ModelNet10数据集的分类实验中,该网络分别取得了92.8%和94.7%的准确率,均高于所对比的同类方法的性能水平。将CIFAR-10和MNIST图像数据集转为点云并进行测试,结果表明网络在2D图像中的性能基本等效于传统2D卷积网络。     

图像抖动核函数估计与图像恢复

抖动模糊是摄影中常见的问题,为此提出了一个鲁棒快速的核函数估计和图像恢复方法。给定一幅因相机抖动而模糊的图像,该方法首先建立金字塔,然后自顶向下、迭代地估计运动模糊核函数,同时对图像进行恢复。使用混合高斯模型对核函数建模,使用自然图像的边缘大尾巴分布对图像进行约束。通过冲击滤波器预测图像的强边缘,对图像的边缘与核函数进行约束,从而更好地估计核函数。并通过迟滞阈值方法和核函数重新定位的方法,降低核函数的噪声,提高核函数估计的鲁棒性能。在求解核函数能量方程时,采用共轭梯度法,利用图像的一阶和二阶偏导数降低系统方程的条件数,加快收敛速度。最后,在一个国际公开的包含32组运动模糊图像的数据集上验证了该方法。实验结果表明,该方法所恢复的图像,其边缘和纹理清晰,能够很好地避免噪声和振铃走样问题。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate