共查询到20条相似文献，搜索用时 671 毫秒
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本文介绍采用Excel处理大学物理实验数据时,利用格拉布斯准则判别粗大误差,并通过实例说明,用宏命令自动剔除粗大误差的方法. 相似文献
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对非齐次等式约束线性回归模型提出一种有偏估计,即条件岭型估计,证明了在一定的条件下,在均方误差及均方误差矩阵意义下都优于回归系数的约束最小二乘估计,并给出了两次随机数据模拟的结果,模拟数据结果表明在一定的条件下,条件岭型估计优于最小二乘估计. 相似文献
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为实现生鲜牛肉嫩度等级的无损快速判别,用可见近红外光谱检测实验系统,获取不同嫩度的40块牛肉样品的400~1650 nm范围的光谱信息,以肉类嫩度测量仪测量牛肉剪切力值为分类依据.用多元散射校正(MSC)、SG平滑处理方法处理光谱数据,分别建立牛肉嫩度的线性判别分类模型和支持向量机分类模型.结果显示,用MSC+SG预处理后所建立的线性判别分类模型预测能力最好,训练集和测试的回判识别率和预测识别率分别为96.7%、100%.结果表明,用光谱技术结合线性判别分析,可以对牛肉嫩度进行无损快速判别. 相似文献
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时非齐次等式约束线性回归模型回归系数提出广义条件岭估计.证明了在一定的条件下,在均方误差矩阵、均方误差及广义均方误差意义下,广义条件岭估计都优于约束最小二乘估计和狭义条件岭估计. 相似文献
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＂用伏安法测电源电动势和内电阻＂实验是中学物理电学基本实验之一,对培养学生实验操作能力、图像法处理数据及误差分析能力起着重要的作用.同时,伏安法也被认为是中学阶段测量电源电动势的各种电路中误差最小的方法.其实这种观点源于人们对另一种＂直接测量法＂的误读.以下从实际实验数据和理论角度对两种测量方法的误差作一个对比分析. 相似文献
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万丽 《河北理科教学研究》2008,(1):41-42
判别数列收敛性的方法有多种,但对迭代数列我们一般采用两种方法来判别:定义法和定理法.用定义法判别是学生最感困难的,而用定理在单调性和有界性的证明中有时也并不是十分容易的.下面介绍一种判别迭代数列收敛性的新方法,在判别收敛性的同时还可得到其收敛值. 相似文献
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本文介绍了“根值判别法“的一种等价形式,该方法把“根值判别法“和“比值判别法“有机地结合起来,能较好地解决某些同号级数敛散性的问题. 相似文献
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MEI Cong-li SU Hong-ye CHU Jian 《浙江大学学报(A卷英文版)》2007,8(6):904-909
A novel mixed integer linear programming （NMILP） model for detection of gross errors is presented in this paper. Yamamura et al.（1988） designed a model for detection of gross errors and data reconciliation based on Akaike information criterion （AIC）. But much computational cost is needed due to its combinational nature. A mixed integer linear programming （MILP） approach was performed to reduce the computational cost and enhance the robustness. But it loses the super performance of maximum likelihood estimation. To reduce the computational cost and have the merit of maximum likelihood estimation, the simultaneous data reconciliation method in an MILP framework is decomposed and replaced by an NMILP subproblem and a quadratic programming （QP） or a least squares estimation （LSE） subproblem. Simulation result of an industrial case shows the high efficiency of the method. 相似文献
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《天津大学学报(英文版)》2017,(6)
Conventional camera calibration that employs calibration targets is a commonly used method to acquire a camera's intrinsic and/or extrinsic parameters. The calibration targets are usually designed as periodic arrays of simple high-contrast patterns that provide highly accurate world coordinate system points and the corresponding image pixel coordinate system points. The existing pixel coordinate extraction algorithms can reach a sub-pixel level; however, they treat each single pattern in one image as an independent individual, which makes it difficult to further improve extraction accuracy. In this paper, a novel method is proposed by utilizing the periodic arrangement characteristics of the calibration target pattern as a global constraint to improve the calibration accuracy. Based on a camera's pinhole model, the intersection point of two fitted curves is used as an optimized pixel point to replace the initial one. Following the pixel coordinate optimization procedures, experiments were performed using real data from a 3D laser line scanner and a dynamic precision calibration target. Our results show that the relative errors of camera homography matrix elements obtained by the proposed optimization method were reduced compared with the commonly used method. The average coordinate measurement accuracy can be improved by nearly 0.05 mm. It is shown that the proposed optimization method can enhance the camera calibration accuracy,especially when the extracted pixels are of poorer precision. 相似文献
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This paper presents a distribution free method for predicting the extreme wind velocity from wind monitoring data at the site
of the Runyang Suspension Bridge (RSB), China using the maximum entropy theory. The maximum entropy theory is a rational approach
for choosing the most unbiased probability distribution from a small sample, which is consistent with available data and contains
a minimum of spurious information. In this paper, the theory is used for estimating a joint probability density function considering
the combined action of wind speed and direction based on statistical analysis of wind monitoring data at the site of the RSB.
The joint probability distribution model is further used to estimate the extreme wind velocity at the deck level of the RSB.
The results of the analysis reveal that the probability density function of the maximum entropy method achieves a result that
fits well with the monitoring data. Hypothesis testing shows that the distributions of the wind velocity data collected during
the past three years do not obey the Gumbel distribution. Finally, our comparison shows that the wind predictions of the maximum
entropy method are higher than that of the Gumbel distribution, but much lower than the design wind speed. 相似文献
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A new method was worked out to improve the precision of springback prediction in sheet metal forming by combining the finite element method (FEM) with the data mining (DM) technique. First the genetic algorithm (GA) was adopted for recognizing the material parameters. Then according to the even design idea, the suitable calculation scheme was confirmed, and FEM was used for calculating the springback. The computation results were compared with experiment data, the difference between them was taken as source data, and a new pattern recognition method of DM called hierarchical optimal map recognition method (HOMR) is applied for summarizing the calculation regulation in FEM. At the end, the mathematics model of the springback simulation was established.Based on the model, the calculation errors of springback can be controlled within 10 % compared with the experimental results. 相似文献
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彭家寅 《内江师范学院学报》2008,23(2):5-10
用模糊熵来度量模糊推理结果的模糊程度,并用极大模糊熵原则对模糊推理α-反向三Ⅰ算法做进一步解释和改进,提出了基于极大模糊熵原理的模糊推理α-反向三Ⅰ算法,讨论了FMP和FMT问题的模糊熵α-反向三Ⅰ支持算法解的存在条件,研究了α-反向三Ⅰ解与模糊熵α-反向三Ⅰ解的关系,获得了几个常见蕴涵算子的FMP问题与FMT问题的模糊熵α-反向三Ⅰ解的计算公式． 相似文献
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孙金礼 《雁北师范学院学报》2008,24(5)
分析了地面控制网、井下导线测量、立井定向和加测陀螺定向边对贯通大型巷道精度的影响;讨论了提高测量精度的可行性方法.同时,就测距导线边长化归到投影水平面和投影到高斯平面的两项改正误差对精度的影响及测距三角高程能否代替井下一级水准等问题,提出了自己的观点. 相似文献
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杨明 《河北能源职业技术学院学报》2003,3(2):69-71,86
由于地质体和地质过程相当复杂，其相应的数学模型也较复杂，模型的求解只能采用数值法近似得到，结果误差大，精度低。要想得到较高的精度，需大大地增加运算量。本文介绍一种新的数值解析解，是基于有限元方法，通过变化单元的划分，消除系统误差，来推出高精度的解。此法方便易行，使用于各种复杂的数学模型，尤其适用于精度较高的计算问题。文中给出一个渗流算例，结果令人满意。 相似文献
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关键词提取是问答系统中问句分析的重要步骤,它有助于问答系统快速、准确地返回答案。针对现有文献中基于T FIDF等方法在关键词提取准确率及效率方面的不足,提出一种基于平均信息熵的中文问句关键词提取方法。通过加入专业领域词汇,并在停用词过滤的基础上计算问句中每个词的平均信息熵,以词的信息熵值直接体现该词在问句中的重要性;同时在关键词提取过程中,通过设定不同提取比例,并在不同提取比例下观察评价标准值,以最佳提取比例获取更为合适的关键词。实验结果表明,与传统的T FIDF等其他方法相比,该方法的查准率、查全率以及 F1测度值都得到显著提高。 相似文献
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提出一种基于Boosting BP神经网络的交通事件检测方法.以上下游的流量和占有率作为特征,BP神经网络作为分类器进行交通事件的自动分类与检测.为了进一步提高神经网络的泛化能力,采用一种调整权值分布,限制权重扩张的改进的Boosting方法,分类器以加权投票方式进行分类决策.实验结果表明该交通事件检测算法是有效的. 相似文献