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基于云模型的仿真可信度评估方法 被引量:9
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作者 郑垚宇 方洋旺 +4 位作者 魏贤智 陈少华 高翔 王宏柯 彭维仕 《计算机应用》 CSCD 北大核心 2018年第6期1535-1541,共7页
针对云模型在非正态分布条件下不适用的问题,提出了基于均匀分布的一维逆向云算法,并将其应用于仿真系统的可信度评估体系。首先,阐述了仿真可信度的重要性,并以实际工程为背景建立了某型装备抗干扰能力评估结果可信度评估指标;其次,运... 针对云模型在非正态分布条件下不适用的问题,提出了基于均匀分布的一维逆向云算法,并将其应用于仿真系统的可信度评估体系。首先,阐述了仿真可信度的重要性,并以实际工程为背景建立了某型装备抗干扰能力评估结果可信度评估指标;其次,运用基于云模型的仿真可信度评估方法对系统进行评估,并对该评估方法进行改进;最后,为了完善该评估方法,推导出基于均匀分布的一维逆向云算法,并且设计实验验证了该算法的有效性。仿真实验结果表明,该逆向云算法在较大数据时平均绝对误差小于5%,具有较高实用性,为云模型理论的完善提供一种思路。此外仿真可信度评估结果表明,该评估方法精度高,包含数据的分散度和凝聚度信息,可以进行更全面评估和错误数据预测。 展开更多
关键词 仿真可信度评估 云模型 逆向云算法 均匀分布 中心矩 残差
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基于多项式逼近算法的精确浮点除法器的设计 被引量:2
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作者 李旭军 石娜 +1 位作者 龙科莅 彭祥 《微电子学与计算机》 2023年第5期90-96,共7页
单精度浮点除法运算在图像处理、科学计算、人工智能等领域有极其广泛的应用.基于泰勒级数展开式对多项式逼近算法进行改进,设计了一个符合IEEE-754标准的精确浮点除法器.为了得到满足忠实舍入的运算结果,对运算过程中的所有误差进行分... 单精度浮点除法运算在图像处理、科学计算、人工智能等领域有极其广泛的应用.基于泰勒级数展开式对多项式逼近算法进行改进,设计了一个符合IEEE-754标准的精确浮点除法器.为了得到满足忠实舍入的运算结果,对运算过程中的所有误差进行分析,完成了对系数和中间结果位宽的设计.为了得到精确舍入的结果,提出一种校准方法对有误差的结果进行校准.为了降低硬件成本,使用均匀分段的方式对运算区间进行分段,控制了系数的数量与查找表的大小.为了提高除法器的工作频率与吞吐量,对设计的除法器提出一种流水线划分方式.后仿真结果表明,精确除法器的误差小于0.5 ulp,延时为2.35 ns,面积为0.185 mm^(2),功耗为69.93 mW. 展开更多
关键词 除法运算 均匀分段 误差分析 精确舍入 流水线
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Rates of convergence of powered order statistics from general error distribution 被引量:1
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作者 Yuhan Zou Yingyin Lu Zuoxiang Peng 《Statistical Theory and Related Fields》 CSCD 2023年第1期1-29,共29页
Let{Xn:n≥1}be a sequence of independent random variables with common general error distribution GED(v)with shape parameter v>0,and let Mn,r denote the r-th largest order statistics of X1,X2,...,Xn.With different n... Let{Xn:n≥1}be a sequence of independent random variables with common general error distribution GED(v)with shape parameter v>0,and let Mn,r denote the r-th largest order statistics of X1,X2,...,Xn.With different normalizing constants the distributional expansions and the uniform convergence rates of normalized powered order statistics|Mn,r|p are established.An alternative method is presented to estimate the probability of the r-th extremes.Numerical analyses are provided to support the main results. 展开更多
关键词 Distributional expansion uniform convergence rate general error distribution powered order statistic
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First passage times for multidimensional denumerable state Markov processes 被引量:3
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作者 XU Guanghui(HSU Guang-Hui) and XU DejuInstitute of Applied Mathematics , Chinese Academy of Sciences , Beijing 100080, China Asian-Pacific Operations Research Center within CAS and APORS , Beijing 100080, China 《Chinese Science Bulletin》 SCIE EI CAS 1999年第11期970-980,共11页
For a general multidimensional denumerable state Markov process with any initial state probability vector, the probability density function and its LS transform of the first passage time to a certain given state set a... For a general multidimensional denumerable state Markov process with any initial state probability vector, the probability density function and its LS transform of the first passage time to a certain given state set are obtained and the algorithms for them are derived. It is proved that the resulting errors of the algorithms are both uniform in their respective arguments.Some numerical results are presented. 展开更多
关键词 MULTIDIMENSIONAL denumerable STATE MARKOV process first PASSAGE time uniformIZATION uniform error.
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幅相误差对阵列天线相位中心的影响分析 被引量:2
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作者 陈曦 杨龙 +1 位作者 吴丹 傅光 《电波科学学报》 EI CSCD 北大核心 2016年第6期1195-1201,共7页
为精确预测阵列天线相位中心的特性,研究了阵列口径的幅相误差对阵列天线相位中心的影响.对阵列天线相位中心的求解方法进行了简要论述,得出了阵列天线相位中心的计算方法;采用该方法对一个算例阵列进行仿真计算,分别引入均匀分布和正... 为精确预测阵列天线相位中心的特性,研究了阵列口径的幅相误差对阵列天线相位中心的影响.对阵列天线相位中心的求解方法进行了简要论述,得出了阵列天线相位中心的计算方法;采用该方法对一个算例阵列进行仿真计算,分别引入均匀分布和正态分布的幅相误差,计算得出不同类型幅相误差造成的天线相位中心变化.分析计算结果可以得出,幅相误差对阵列天线相位中心可造成显著影响,并且该影响与幅相误差分布类型和误差限有关.该研究结论可用于指导高精度阵列天线的设计. 展开更多
关键词 阵列天线 相位中心 幅相误差 均匀分布 正态分布
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最佳一致逼近及容差平滑圆弧拟合平面点列 被引量:3
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作者 肖涤尘 梁锡昌 《重庆大学学报(自然科学版)》 EI CAS CSCD 1989年第3期35-43,共9页
本文应用最佳一致逼近及容差平滑的分段圆弧拟合列表点列平面曲线。本方法具有拟合误差最小;误差不大于给定值时,拟合圆弧段数最少;圆弧段交接处平滑性可控;一定的平滑数据作用,便于直接用于数控加工、绘图等优点和工程实用意义。
关键词 最佳 一致 逼近 容差 平滑 园弧
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二次曲线 Chebyshev 法向逼近的交换算法 被引量:2
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作者 龚劬 《重庆大学学报(自然科学版)》 EI CAS CSCD 1997年第4期60-63,共4页
以机械曲线的逼近为背景,建立了符合机械上误差度量标准的逼近模型即法向一致逼近问题,推出了最佳法向一致逼近二次曲线的特征,给出了一个算法,并对其收敛性进行了讨论,最后将此法用于齿轮齿廓的二次曲线逼近,其误差低于0.8μm.
关键词 切比雪夫逼近 一致逼近 逼近误差 曲线逼近
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解对流占优反应扩散问题一致稳定的差分格式 被引量:3
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作者 张铁 王宝艳 《高校应用数学学报(A辑)》 CSCD 北大核心 2010年第2期195-201,共7页
通过将一般的反应扩散方程转化为主部为守恒型方程形式,构造出一种稳定和高精度的新型差分格式.这种差分格式最大的优点是具有与方程Peclet数和网格步长无关的一致稳定性,特别适合求解强对流占优问题或边界层问题.同时还给出了差分格式... 通过将一般的反应扩散方程转化为主部为守恒型方程形式,构造出一种稳定和高精度的新型差分格式.这种差分格式最大的优点是具有与方程Peclet数和网格步长无关的一致稳定性,特别适合求解强对流占优问题或边界层问题.同时还给出了差分格式按L_∞模的一致稳定性和O(h^2)阶收敛速度的理论分析.数值实验验证了理论分析结果. 展开更多
关键词 强对流占优问题 差分方法 一致稳定性 误差分析
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效应物置入对环境电磁辐射场强测试的影响 被引量:3
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作者 魏光辉 纪凯夫 孟令媛 《北京理工大学学报》 EI CAS CSCD 北大核心 2019年第11期1173-1179,1186,共8页
为降低效应物置入对环境电场强度测量的影响,提高电磁辐射敏感度测试准确度,采用电磁场数值计算与实验验证相结合的方法,以正立方良导体作为效应物的模型,分别研究了效应物置入均匀电场环境或电磁混响室中导致的电场分布变化规律,以效... 为降低效应物置入对环境电场强度测量的影响,提高电磁辐射敏感度测试准确度,采用电磁场数值计算与实验验证相结合的方法,以正立方良导体作为效应物的模型,分别研究了效应物置入均匀电场环境或电磁混响室中导致的电场分布变化规律,以效应物置入前的环境电场强度作基准,确定了在典型方位测量环境电场强度时由于电场畸变导致的相对误差,给出了测量误差随距效应物相对距离的变化曲线.研究结果表明:在效应物前端面对角线方向测量环境电场误差较小,当相对距离l/λ>1时,均可将环境电场强度的相对误差控制在±10%以内,低频测量时,测试距离处于(0.15~0.25)λ之间时,环境电场强度测试误差可控制在15%以内,满足测量误差要求;混响室中置入效应物,电场畸变主要影响其表面附近的平均场强分布,只要偏离效应物表面大于0.4λ,效应物置入引起的电场畸变对环境电场强度测量造成的误差就能控制在2 dB以内;距离效应物表面(0.5~0.9)λ时,电场相对误差更小,建议在该范围内进行环境电场强度测试. 展开更多
关键词 电磁环境 混响室 均匀场 效应物 电场畸变 测量误差
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First passage times: Busy periods and waiting times 被引量:1
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作者 徐光煇 袁学明 《Science China Mathematics》 SCIE 1995年第10期1187-1201,共15页
General expressions of first passage times for denumerable Markov processes are discussed and computation problems for busy periods and waiting times for queues corresponding to Markov processes are studied. In partic... General expressions of first passage times for denumerable Markov processes are discussed and computation problems for busy periods and waiting times for queues corresponding to Markov processes are studied. In particular, the simplified algorithms for busy periods and waiting times for queues corresponding to G//M/1 type and M/G/1 type Markov processes are derived and some numerical examples are presented. 展开更多
关键词 denumerable MARKOV PROCESS first PASSAGE time G1/M/1 TYPE MARKOV PROCESS M/G/1 MARKOV PROCESS M/G/1 TYPE MARKOV PROCESS uniform error.
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Study on Real-time Look-ahead and Adaptive Parametric Curve Interpolator 被引量:2
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作者 郭伟 杜道山 +1 位作者 徐荣珍 李从心 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第3期388-393,共6页
The principle of real-time look-ahead was introduced and analysed. An adaptive parametric curve interpolator with a real-time look-ahead function was developed for non-uniform rational B-spline (NURBS) curves interpol... The principle of real-time look-ahead was introduced and analysed. An adaptive parametric curve interpolator with a real-time look-ahead function was developed for non-uniform rational B-spline (NURBS) curves interpolation, which considering the maximum acceleration/deceleration of the machine tool. In order to deal with the acceleration/deceleration around the feedrate sensitive corners, the look-ahead function was designed and illustrated. It can detect and adjust the feedrate adaptively. With the help of real-time look-ahead, the acceleration/deceleration can be limited to the range of the machine tool capacity. Thus, feedrate fluctuation is reduced. A NURBS curve interpolation experiment was provided to verify the feasibility and advantages of the proposed interpolator with a real-time look-ahead function. 展开更多
关键词 adaptive interpolator LOOK-AHEAD non-uniform rational B-spline curves feedrate sensitive corner chord error
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UNIFORM STABILITY AND ERROR ANALYSIS FOR SOME DISCONTINUOUS GALERKIN METHODS 被引量:1
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作者 Qingguo Hong Jinchao Xu 《Journal of Computational Mathematics》 SCIE CSCD 2021年第2期283-310,共28页
In this paper,we provide a number of new estimates on the stability and convergence of both hybrid discontinuous Galerkin(HDG)and weak Galerkin(WG)methods.By using the standard Brezzi theory on mixed methods,we carefu... In this paper,we provide a number of new estimates on the stability and convergence of both hybrid discontinuous Galerkin(HDG)and weak Galerkin(WG)methods.By using the standard Brezzi theory on mixed methods,we carefully define appropriate norms for the various discretization variables and then establish that the stability and error estimates hold uniformly with respect to stabilization and discretization parameters.As a result,by taking appropriate limit of the stabilization parameters,we show that the HDG method converges to a primal conforming method and the WG method converges to a mixed conforming method. 展开更多
关键词 uniform Stability uniform error Estimate Hybrid Discontinuous Galerkin Weak Galerkin
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First passage times for Markov renewal processes and applications
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作者 徐光煇 袁学明 李泉林 《Science China Mathematics》 SCIE 2000年第12期1238-1249,共12页
This paper proposes a uniformly convergent algorithm for the joint transform of the first passage time and the first passage number of steps for general Markov renewal processes with any initial state probability vect... This paper proposes a uniformly convergent algorithm for the joint transform of the first passage time and the first passage number of steps for general Markov renewal processes with any initial state probability vector. The uniformly convergent algorithm with arbitrarily prescribed error can be efficiently applied to compute busy periods, busy cycles, waiting times, sojourn times, and relevant indices of various generic queueing systems and queueing networks. This paper also conducts a numerical experiment to implement the proposed algorithm. 展开更多
关键词 MARKOV RENEWAL process (MRP) joint transform first PASSAGE time BUSY period BUSY cycle uniform error.
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GENERALIZATION PERFORMANCE OF MULTI-CATEGORY KERNEL MACHINES——In Memory of Professor Sun Yongsheng
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作者 Hong Chen Luoqing Li 《Analysis in Theory and Applications》 2007年第2期188-195,共8页
Support vector machines are originally designed for binary classification. How to effectively extend it for multi-class classification is still an on-going research issue. In this paper, we consider kernel machines wh... Support vector machines are originally designed for binary classification. How to effectively extend it for multi-class classification is still an on-going research issue. In this paper, we consider kernel machines which are natural extensions of multi-category support vector machines originally proposed by Crammer and Singer. Based on the algorithm stability, we obtain the generalization error bounds for the kernel machines proposed in the paper. 展开更多
关键词 Kernel machine uniform stability generalization error
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Error Estimates for the Difference Method to System of Ordinary Differential Equations with Boundary Layer
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作者 Ilhame Amirali 《Journal of Applied Mathematics and Physics》 2013年第5期79-84,共6页
This work deals with the numerical solution of singular perturbation system of ordinary differential equations with boundary layer. For the numerical solution of this problem fitted finite difference scheme on a unifo... This work deals with the numerical solution of singular perturbation system of ordinary differential equations with boundary layer. For the numerical solution of this problem fitted finite difference scheme on a uniform mesh is constructed and analyzed. The uniform error estimates for the approximate solution are obtained. 展开更多
关键词 SINGULAR PERTURBATION Linear System Difference Scheme uniform Convergence error ESTIMATES
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Algorithms for Markov stochastic models
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作者 XU Guanghui (HSU Guang-Hui)Institute of Applied Mathematics, Chinese Academy of Sciences, Asian-Pacific Operations Research Center Within CAS and APORS, Beijing 100080, China 《Chinese Science Bulletin》 SCIE EI CAS 1999年第2期97-100,共4页
A survey of the main results of algorithmic studies of Markov processes and related stochastic models is shown. It consists of stationary solutions, transient solutions, first passage times, and multidimensional denum... A survey of the main results of algorithmic studies of Markov processes and related stochastic models is shown. It consists of stationary solutions, transient solutions, first passage times, and multidimensional denumerable state Markov processes. In conclusion, some remarks on further works are presented. 展开更多
关键词 MARKOV process stochastic model algorithm STATIONARY SOLUTIONS TRANSIENT SOLUTIONS first PASSAGE time uniform error.
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基于均匀设计搜索算法的圆度误差评定技术研究 被引量:1
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作者 徐晓栋 龚非 常明珠 《工具技术》 北大核心 2016年第12期96-99,共4页
为了提高圆度误差的评定精度和效率,提出均匀设计搜索算法的圆度误差评定方法。首先随机取点构造圆,以该圆心为中心做边长为零件精度两倍的正方形,采用均匀设计搜索算法,计算均匀搜索点与测量点距离的极大值、极小值和极差;然后以最小... 为了提高圆度误差的评定精度和效率,提出均匀设计搜索算法的圆度误差评定方法。首先随机取点构造圆,以该圆心为中心做边长为零件精度两倍的正方形,采用均匀设计搜索算法,计算均匀搜索点与测量点距离的极大值、极小值和极差;然后以最小极差值为新圆心,不断缩小正方形半径,直到搜索终止。经实例证明,均匀设计搜索算法简单,评定精度高,搜敛速度快,对实际圆度误差评定有指导意义。 展开更多
关键词 搜索算法 均匀设计 圆度误差
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伪随机码用于靶场武器系统的精密测时 被引量:1
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作者 马瑞平 《无线电工程》 2006年第6期39-40,53,共3页
伪随机码具有类似于白噪声的自相关函数及频谱特性,具有扩展频谱的功能,具有较强的抗干扰能力。伪随机码广泛应用于通信及测控领域。介绍了伪随机码的主要特点,简要描述了伪随机码测时的工作原理,对系统的测时精度进行了详细分析、计算... 伪随机码具有类似于白噪声的自相关函数及频谱特性,具有扩展频谱的功能,具有较强的抗干扰能力。伪随机码广泛应用于通信及测控领域。介绍了伪随机码的主要特点,简要描述了伪随机码测时的工作原理,对系统的测时精度进行了详细分析、计算并得到了期望的结果。分析及试验表明,系统测时精度满足任务要求。最后得到结论,利用伪随机码技术进行靶场武器系统的精密时间测量是可行的。 展开更多
关键词 伪随机码 精密测时 均匀分布 随机误差
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分层网格上半奇异摄动问题的有限元逼近 被引量:1
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作者 朱国庆 李清善 陈绍春 《广西师范大学学报(自然科学版)》 CAS 北大核心 2007年第3期48-51,共4页
考虑半奇异摄动反应扩散问题的双线性有限元逼近。首先给出关于真解的一些新的正则性估计。在先验分层网格剖分基础上,在ε-加权H1-模意义下得到了拟最优阶一致收敛的误差估计。
关键词 半奇异摄动方程 分层网格 一致收敛 误差估计
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The Convergence of 1-Periodic Branched Continued Fraction of the Special Form in Parabolic Regions
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作者 Dmytro I. Bodnar Mariia M. Bubniak 《Journal of Mathematics and System Science》 2014年第4期269-274,共6页
Branched continued fractions are one of the multidimensional generalization of the continued fractions. Branched continued fractions with not equivalent variables are an analog of the regular C-fractions for multiple ... Branched continued fractions are one of the multidimensional generalization of the continued fractions. Branched continued fractions with not equivalent variables are an analog of the regular C-fractions for multiple power series. We consider 1-periodic branched continued fraction of the special form which is an analog fraction with not equivalent variables if the values of that variables are fixed. We establish an analog of the parabola theorem for that fraction and estimate truncation error bounds for that fractions at some restrictions. We also propose to use weight coefficients for obtaining different parabolic regions for the same fraction without any additional restriction for first element. 展开更多
关键词 Continued fractions 1-periodic branched continued fraction of special form CONVERGENCE uniform convergence truncation error bounds.
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