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矩阵型布鲁姆过滤器在病毒过滤防火墙中的研究 被引量:1
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作者 王景中 杜飞 《计算机应用》 CSCD 北大核心 2009年第11期2939-2941,3010,共4页
针对传统的基于特征码的病毒过滤算法在实际运行中存在的效率问题,提出了一种基于矩阵型布鲁姆过滤器(MBF)的病毒过滤算法。在分析该算法的空间效率、时间效率以及错误判断率的基础上,进一步研究了它的数学模型,并给出了该算法在高速病... 针对传统的基于特征码的病毒过滤算法在实际运行中存在的效率问题,提出了一种基于矩阵型布鲁姆过滤器(MBF)的病毒过滤算法。在分析该算法的空间效率、时间效率以及错误判断率的基础上,进一步研究了它的数学模型,并给出了该算法在高速病毒过滤引擎中的设计方案。最后,通过仿真实验验证该算法的有效性和实用性。 展开更多
关键词 病毒特征码 矩阵型布鲁姆过滤 哈希算法
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一种面向闪存键值存储的矩阵索引布鲁姆过滤器
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作者 李玮 张大方 +2 位作者 谢鲲 黎文伟 何杰 《计算机研究与发展》 EI CSCD 北大核心 2015年第5期1210-1222,共13页
索引结构是提高闪存键值存储插入和查询性能的关键技术之一.在分析目前相关索引结构特点的基础上提出了一种面向闪存键值存储的矩阵索引布鲁姆过滤器(matrix-indexed Bloom filter,MIBF),由m×s的位矩阵表示的多个布鲁姆过滤器组(mu... 索引结构是提高闪存键值存储插入和查询性能的关键技术之一.在分析目前相关索引结构特点的基础上提出了一种面向闪存键值存储的矩阵索引布鲁姆过滤器(matrix-indexed Bloom filter,MIBF),由m×s的位矩阵表示的多个布鲁姆过滤器组(multiple Bloom filter group,MBFG)和一个附加布鲁姆过滤器(additional Bloom filter,ABF)组成,其核心思想是键值对的闪存页地址被拆分为多组位串,每组位串采用MBFG中的一组布鲁姆过滤器(Bloom filter,BF)来表示,同时将键值对的Key与闪存页地址组合值存入ABF中.根据Key查询Value时,MBFG中的每组BF产生多位,组合生成键值对的闪存页地址,并通过ABF滤掉部分伪闪存页地址达到较精确地址定位,从而降低闪存访问次数,提高系统性能.与已有类似方法相比,MIBF的查询地址定位精度提高,内存和闪存访问次数降低明显,插入和查询性能显著提升. 展开更多
关键词 键值存储 闪存页地址 索引结构 布鲁姆过滤 矩阵索引布鲁姆过滤
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一个基于分布式并行过滤的前置式邮件过滤模型 被引量:1
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作者 孙晓斌 郑宇 吴耿锋 《计算机应用与软件》 CSCD 北大核心 2006年第12期88-89,118,共3页
提出一种新的邮件过滤模型———基于分布式并行过滤的通用前置式邮件过滤模型PDPF,由此构造的邮件过滤系统,其运行不依赖于特定的邮件服务器而在网关提供过滤服务,对到达的邮件进行并行过滤处理,其分布式并行过滤矩阵通过“并行与”操... 提出一种新的邮件过滤模型———基于分布式并行过滤的通用前置式邮件过滤模型PDPF,由此构造的邮件过滤系统,其运行不依赖于特定的邮件服务器而在网关提供过滤服务,对到达的邮件进行并行过滤处理,其分布式并行过滤矩阵通过“并行与”操作,能够加快过滤速度。在真实环境下的实验表明,在日均邮件流量高达10万封的情况下,每封邮件的处理时间不超过50m s。 展开更多
关键词 SMTP前置式邮件过滤模型 分布式并行过滤矩阵 并行与操作
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Jordan标准化问题的入一矩阵初等变换法
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作者 郭淑娟 《新乡师范高等专科学校学报》 1999年第1期 103-107,共5页
本文运用入一矩阵的不变因子理论导出了求Jordan标准化问题的入一矩阵初等变换方法。运用这种方法可以直接求任-n阶矩阵的A的Jordan标准形和过渡矩阵。
关键词 入一矩阵 入一矩阵初等变换 不变因子 JORDAN标准形 过滤矩阵
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一种恢复图像自然色彩的重构方法 被引量:1
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作者 陶霖密 袁春 王浩达 《智能系统学报》 CSCD 北大核心 2019年第5期877-881,共5页
现代数码相机是通过颜色过滤矩阵在每个像素位置采集一个颜色分量,重构出全彩色数字图像。压缩感知理论证明了该重构是误差有界的,但在实际应用时却隐含着一个问题:重构图像所需的稀疏编码字典是从图像数据库学习出来的,而目前数字图像... 现代数码相机是通过颜色过滤矩阵在每个像素位置采集一个颜色分量,重构出全彩色数字图像。压缩感知理论证明了该重构是误差有界的,但在实际应用时却隐含着一个问题:重构图像所需的稀疏编码字典是从图像数据库学习出来的,而目前数字图像都是重构出来的,因此存在着从重构的图像学习字典去重构图像的循环悖论。针对这个问题,提出并构建了新的完全采样彩色图像的Sandwich图像数据集,打破了压缩感知理论在应用于图像重构时的循环悖论,使得压缩感知方法能够真正地重建自然彩色图像。Sandwich图像数据集的构建及其训练得到的字典可以应用于如图像超分辨率重构、去噪、修复等领域。深入的图像重建实验表明,使用sandwich图像集训练的字典不论是字典原子特性还是由其重构得到的图像质量均好于基于传统数据集的结果。 展开更多
关键词 颜色过滤矩阵 压缩感知 稀疏编码 字典学习 图像重构 自然色彩
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Network-Based H_∞ Filtering for Linear Systems with Randomly Varying Sensor Delay 被引量:1
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作者 刘金良 韩华 胡一帆 《Journal of Donghua University(English Edition)》 EI CAS 2011年第4期400-404,共5页
An H∞ filter design for linear time delay system with randomly varying sensor delay is investigated.The delay considered here is assumed to satisfy a certain stochastic characteristic.A stochastic variable satisfying... An H∞ filter design for linear time delay system with randomly varying sensor delay is investigated.The delay considered here is assumed to satisfy a certain stochastic characteristic.A stochastic variable satisfying Bernoulli random binary distribution is introduced and a new system model is established by employing the measurements with random delay.By using the linear matrix inequality(LMI) technique,sufficient conditions are derived for ensuring the mean-square stochastic stability of the filtering error systems and guaranteeing a prescribed H∞ filtering performance.Finally,a numerical example is given to demonstrate the effectiveness of the proposed approach. 展开更多
关键词 H∞ filter design linear matrix inequality (LMI) time-varying delay matrix function convex
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Robust H_∞ filtering for neutral jump system with time-delays and uncertainties
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作者 何舒平 刘飞 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2009年第1期41-46,共6页
The problem of robust H∞ filtering for a class of neutral jump systems with time-delay and norm- bounded uncertainties is considered. By re-constructing the system, the dynamics of overall augmented error systems is ... The problem of robust H∞ filtering for a class of neutral jump systems with time-delay and norm- bounded uncertainties is considered. By re-constructing the system, the dynamics of overall augmented error systems is obtained which involves unknown inputs represented by disturbances, model uncertainties and time-delays. As to the nominal system, sufficient conditions are provided for the existence of the mode-dependent H∞ filter by selecting the appropriate Lyapunov-Krasovskii function and the robust H∞ filter is proposed for the jump system while considering the time-delays and uncertainties. Both of above conditions for the existence of the H∞ filter and roust H∞ filter are presented in terms of linear matrix inequalities, and convex optimization problems are formulated to design the desired filters. By employing the proposed mode-dependent H∞ filter, the systems have the stochastic stability and better ability of restraining disturbances stochastically, and the given prescribed H∞ performance is guaranteed. Simulation resuhs illustrate the effectiveness of developed techniques. 展开更多
关键词 neutral jump systems robust H∞ filtering TIME-DELAYS UNCERTAINTIES linear matrix inequality
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A NONMONOTONE LINE SEARCH FILTER METHOD WITH REDUCED HESSIAN UPDATING FOR NONLINEAR OPTIMIZATION 被引量:1
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作者 GU Chao ZHU Detong 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2013年第4期534-555,共22页
This paper proposes a nonmonotone line search filter method with reduced Hessian updating for solving nonlinear equality constrained optimization.In order to deal with large scale problems,a reduced Hessian matrix is ... This paper proposes a nonmonotone line search filter method with reduced Hessian updating for solving nonlinear equality constrained optimization.In order to deal with large scale problems,a reduced Hessian matrix is approximated by BFGS updates.The new method assures global convergence without using a merit function.By Lagrangian function in the filter and nonmonotone scheme,the authors prove that the method can overcome Maratos effect without using second order correction step so that the locally superlinear convergence is achieved.The primary numerical experiments are reported to show effectiveness of the proposed algorithm. 展开更多
关键词 CONVERGENCE filter method lagrangian function line search maratos effect nomnono- tone.
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An improved adaptive Sage filter with applications in GEO orbit determination and GPS kinematic positioning 被引量:3
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作者 XU TianHe JIANG Nan SUN ZhangZhen 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第5期892-898,共7页
The shortcomings of an adaptive Sage filter are analyzed in this paper.An improved adaptive Sage filter is developed by using a weighted average quadratic form of the historical residuals of observations and predicted... The shortcomings of an adaptive Sage filter are analyzed in this paper.An improved adaptive Sage filter is developed by using a weighted average quadratic form of the historical residuals of observations and predicted states to evaluate the covariance matrices of observations and dynamic model errors at the present epoch.The weight function is constructed based on the variances of observational residuals or predicted state residuals and the space distance between the previous and the present epoch.In order to balance the contributions of the measurements and the dynamic model information,an adaptive factor is applied by using a two-segment function and predicted state discrepancy statistics.Two applications,orbit determination of a maneuvered GEO satellite and GPS kinematic positioning,are conducted to verify the performance of the proposed method. 展开更多
关键词 Kalman filter adaptive Sage filter orbit determination kinematic positioning two-segment function
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