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The smoothed finite element method (S-FEM):A framework for the design of numerical models for desired solutions
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作者 Gui-Rong Liu 《结构与土木工程前沿:英文版》 EI CSCD 2019年第2期456-477,共22页
The smoothed finite element method (S-FEM) was originated by G R Liu by combining some meshfree techniques with the well-established standard finite element method (FEM). It has a family of models carefully designed w... The smoothed finite element method (S-FEM) was originated by G R Liu by combining some meshfree techniques with the well-established standard finite element method (FEM). It has a family of models carefully designed with innovative types of smoothing domains. These models are found having a number of important and theoretically profound properties. This article first provides a concise and easy-to-follow presentation of key formulations used in the S-FEM. A number of important properties and unique features of S-FEM models are discussed in detail, including 1) theoretically proven softening effects;2) upper-bound solutions;3) accurate solutions and higher convergence rates;4) insensitivity to mesh distortion;5) Jacobian?free;6) volumetric-locking-free;and most importantly 7) working well with triangular and tetrahedral meshes that can be automatically generated. The S-FEM is thus ideal for automation in computations and adaptive analyses, and hence has profound impact on Al-assisted modeling and simulation. Most importantly, one can now purposely design an S-FEM model to obtain solutions with special properties as wish, meaning that S-FEM offers a framework for design numerical models with desired properties. This novel concept of numerical model demand may drastically change the landscape of modeling and simulation. Future directions of research are also provided. 展开更多
关键词 computational METHOD FINITE ELEMENT METHOD smoothed FINITE ELEMENT METHOD strain SMOOTHING technique SMOOTHING domain weakened weak form solid mechanics SOFTENING effect upper bound solution
A new error-controllable method for smoothing the G01 commands
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作者 Min WAN Wan-Jing XING +2 位作者 Yang LIU Qun-Bao XIAO Wei-Hong ZHANG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第7期1756-1771,共16页
In real machining, the tool paths are composed of a series of short line segments, which constitute groups of sharp corners correspondingly leading to geometry discontinuity in tangent. As a result, high acceleration ... In real machining, the tool paths are composed of a series of short line segments, which constitute groups of sharp corners correspondingly leading to geometry discontinuity in tangent. As a result, high acceleration with high fluctuation usually occurs. If these kinds of tool paths are directly used for machining, the feedrate and quality will be greatly reduced. Thus, generating continuous tool paths is strongly desired. This paper presents a new error-controllable method for generating continuous tool path. Different from the traditional method focusing on fitting the cutter locations, the proposed method realizes globally smoothing the tool path in an error-controllable way. Concretely, it does the smoothing by approaching the newly produced curve to the linear tool path by taking the tolerance requirement as a constraint. That is, the error between the desired tool path and the G01 commands are taken as a boundary condition to ensure the finally smoothed curve being within the given tolerance. Besides, to improve the smoothing ability in case of small corner angle, an improved local smoothing method is also proposed by symmetrically assigning the control points to the two adjacent linear segments with the constrains of tolerance and G3 continuity. Experiments on an open five-axis machine are developed to verify the advantages of the proposed methods. 展开更多
关键词 Energy APPROXIMATION METHOD Error-controllable global SMOOTHING METHOD G3 CONTINUITY Local SMOOTHING METHOD Quasi-uniform quintic Bspline CURVE
基于轮轨关系的钢轨打磨代表廓形计算方法研究 预览
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作者 丁军君 吴朋朋 +1 位作者 王军平 李芾 《铁道学报》 EI CAS CSCD 北大核心 2019年第7期135-140,共6页
钢轨廓形打磨能有效延长钢轨使用寿命,打磨过程中的一个重要步骤是从多个实测钢轨廓形中选取或计算一个代表廓形,与目标廓形对比后对打磨电机磨石角度进行排列安排。针对实测钢轨廓形数据中均存在的周期性或偶发脉冲干扰问题,利用Savitz... 钢轨廓形打磨能有效延长钢轨使用寿命,打磨过程中的一个重要步骤是从多个实测钢轨廓形中选取或计算一个代表廓形,与目标廓形对比后对打磨电机磨石角度进行排列安排。针对实测钢轨廓形数据中均存在的周期性或偶发脉冲干扰问题,利用Savitzky-Golay平滑法能很好地保持曲线形状,同时又达到较好的平滑效果。基于轮轨接触几何关系及接触点位置的概率分布,分析采用算术平均、加权平均、最小二乘距离法和散点拟合法计算得到的钢轨代表廓形与实测钢轨廓形组的轮轨接触点分布曲线相关性。结果表明:无论是在直线还是曲线区段,算术平均法的结果均最贴近实测数据结果,其次是散点拟合法的结果,加权平均、最小二乘距离法的结果相符程度较低。 展开更多
关键词 钢轨廓形 平滑 代表廓形 轮轨接触 相关系数
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Variable Selection via Generalized SELO-Penalized Cox Regression Models
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作者 SHI Yueyong XU Deyi +1 位作者 CAO Yongxiu JIAO Yuling 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2019年第2期709-736,共28页
The seamless-L0(SELO) penalty is a smooth function that very closely resembles the L0 penalty, which has been demonstrated theoretically and practically to be effective in nonconvex penalization for variable selection... The seamless-L0(SELO) penalty is a smooth function that very closely resembles the L0 penalty, which has been demonstrated theoretically and practically to be effective in nonconvex penalization for variable selection. In this paper, the authors first generalize the SELO penalty to a class of penalties retaining good features of SELO, and then develop variable selection and parameter estimation in Cox models using the proposed generalized SELO(GSELO) penalized log partial likelihood(PPL) approach. The authors show that the GSELO-PPL procedure possesses the oracle property with a diverging number of predictors under certain mild, interpretable regularity conditions. The entire path of GSELO-PPL estimates can be efficiently computed through a smoothing quasi-Newton(SQN) with continuation algorithm. The authors propose a consistent modified BIC(MBIC) tuning parameter selector for GSELO-PPL, and show that under some regularity conditions, the GSELOPPL-MBIC procedure consistently identifies the true model. Simulation studies and real data analysis are conducted to evaluate the finite sample performance of the proposed method. 展开更多
关键词 CONTINUATION Cox models GENERALIZED SELO modified BIC penalized LIKELIHOOD SMOOTHING QUASI-NEWTON
A three-dimensional two-level gradient smoothing meshfree method for rainfall induced landslide simulations
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作者 Dongdong WANG Jiarui WANG +2 位作者 Junchao WU Junjun DENG Ming SUN 《结构与土木工程前沿:英文版》 EI CSCD 2019年第2期337-352,共16页
A three-dimensional two-level gradient smoothing meshfree method is presented for rainfall induced landslide simulations. The two-level gradient smoothing for meshfree shape function is elaborated in the threedimensio... A three-dimensional two-level gradient smoothing meshfree method is presented for rainfall induced landslide simulations. The two-level gradient smoothing for meshfree shape function is elaborated in the threedimensional Lagrangian setting with detailed implementation procedure. It is shown that due to the successive gradient smoothing operation without the requirement of derivative computation in the present formulation, the two-level smoothed gradient of meshfree shape function is capable of achieving a given influence domain more efficiently than the standard gradient of meshfree shape function. Subsequently, the two-level smoothed gradient of meshfree shape function is employed to discretize the weak form of coupled rainfall seepage and soil motion equations in a nodal integration format, as provides an efficient three-dimensional regularized meshfree formulation for large deformation rainfall induced landslide simulations. The exponential damage and pressure dependent plasticity relationships are utilized to describe the failure evolution in landslides. The plastic response of soil is characterized by the true effective stress measure, which is updated according to the rotationally neutralized objective integration algorithm. The effectiveness of the present threedimensional two?level gradient smoothing meshfree method is demonstrated through numerical examples. 展开更多
关键词 meshfree method LANDSLIDE RAINFALL THREE-DIMENSIONAL TWO-LEVEL GRADIENT SMOOTHING nodal integration
基于卷积网络的边缘保持滤波方法 预览
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作者 石晓红 黄钦开 +1 位作者 苗佳欣 苏卓 《计算机科学》 CSCD 北大核心 2019年第9期277-283,共7页
边缘保持滤波是计算机视觉、图像处理领域的重要基础理论研究,作为图像预处理操作对后续的处理结果有着重要影响。区别于传统滤波方法,边缘保持滤波方法不仅注重图像的平滑处理,还注重保持边缘细节。卷积神经网络在很多领域得到了应用,... 边缘保持滤波是计算机视觉、图像处理领域的重要基础理论研究,作为图像预处理操作对后续的处理结果有着重要影响。区别于传统滤波方法,边缘保持滤波方法不仅注重图像的平滑处理,还注重保持边缘细节。卷积神经网络在很多领域得到了应用,并取得显著的成果。本文将卷积神经网络引入边缘保持滤波,利用卷积神经网络的良好扩展性和灵活性来构建深度卷积神经网络模型(Deep Convolutional Neural Network,DCNN),通过3种类型的网络堆叠层,采用反向传播迭代更新网络参数,训练残差图像,实现基于DCNN的边缘保持滤波方法;还构建了基于梯度域的卷积神经网络模型(Gradient CNN,GCNN),对彩色图像的梯度信息进行学习,通过三层卷积对梯度图进行边缘保持平滑操作,得到边缘保持平滑梯度图,进而利用输入图像引导平滑梯度图进行彩色重建,得到彩色滤波图像。最后通过实验与常见的边缘保持滤波方法进行主观和客观评价对比。DCNN不仅在视觉上达到了其他滤波的效果,同时在处理时间上也存在较大优势,表明DCNN可以通过大量的数据训练有效地拟合出多种边缘保持滤波算法。与其他边缘保持滤波结果相比,GCNN在视觉上可以保持颜色风格与输入图像整体一致,而且图像相似度评价指标也更好,表明GCNN解决了部分滤波处理出现颜色偏差、梯度反转等问题,而且提高了处理效率。 展开更多
关键词 滤波 边缘保持 平滑操作 卷积神经网络
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Fast and Error-Bounded Space-Variant Bilateral Filtering
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作者 Meng-Ke Yuan Long-Quan Dai +3 位作者 Dong-Ming Yan Li-Qiang Zhang Jun Xiao Xiao-Peng Zhang 《计算机科学技术学报:英文版》 SCIE EI CSCD 2019年第3期550-568,共19页
The traditional space-invariant isotropic kernel utilized by a bilateral filter(BF)frequently leads to blurry edges and gradient reversal artifacts due to tlie existence of a large amount of outliers in the local aver... The traditional space-invariant isotropic kernel utilized by a bilateral filter(BF)frequently leads to blurry edges and gradient reversal artifacts due to tlie existence of a large amount of outliers in the local averaging window.However,the efficient and accurate cstiinatioii of space-variant k(4rnels which adapt to image structures,and the fast realization of the corresponding space-variant bilateral filtering are challenging problems.To address these problems,we present a space-variant BF(SVBF).and its linear time and error-bounded acceleration method.First,we accurately estimate spacevariant,anisotropic kernels that vary with image structures in linear time through structure tensor and mininnini spanning tree.Second,we perform SVBF in linear time using two error-bounded approximation methods,namely,low-rank tensor approximation via higher-order singular value decomposition and exponential sum approximation.Tlierefore.the proposed SVBF can efficiently achieve good edge-preserving results.We validate the advantages of the proposed filter in applications including:image denoising,image enhancement,and image focus editing.Experimental results(leinonstrate that our fast and error-bounded SVBF is superior to state-of-the-art methods. 展开更多
关键词 error-bounded ACCELERATION edge-aware SMOOTHING space-variant BILATERAL FILTERING
ANALYTICAL SMOOTHING EFFECT OF SOLUTION FOR THE BOUSSINESQ EQUATIONS 预览
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作者 程峰 徐超江 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第1期165-179,共15页
In this article, we study the analytical smoothing effect of Cauchy problem for the incompressible Boussinesq equations. Precisely, we use the Fourier method to prove that the Sobolev H~1 -solution to the incompressib... In this article, we study the analytical smoothing effect of Cauchy problem for the incompressible Boussinesq equations. Precisely, we use the Fourier method to prove that the Sobolev H~1 -solution to the incompressible Boussinesq equations in periodic domain is analytic for any positive time. So the incompressible Boussinesq equations admit exactly same smoothing effect properties of incompressible Navier-Stokes equations. 展开更多
关键词 ANALYTICITY SMOOTHING effect of SOLUTIONS BOUSSINESQ EQUATION
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基于B样条曲线的无人机航路修正方法研究
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作者 张弛 丁轶 《信息化研究》 2019年第2期13-17,共5页
B样条曲线(B-spline curve)是贝塞尔曲线的一种一般化,具有几何不变性、凸包性、保凸性、变差减小性、局部支撑性等许多优良性质,可用于给几何体建造精确模型。文章介绍了B样条曲线的定义、特征、基本算法,将其应用于无人机航路修正与... B样条曲线(B-spline curve)是贝塞尔曲线的一种一般化,具有几何不变性、凸包性、保凸性、变差减小性、局部支撑性等许多优良性质,可用于给几何体建造精确模型。文章介绍了B样条曲线的定义、特征、基本算法,将其应用于无人机航路修正与平滑处理,以保证无人机能在航路上正常飞行,并通过仿真验证其有效性。 展开更多
关键词 B样条曲线 航路修正 平滑处理
改进的SMC-CBMeMBer前向后向平滑检测前跟踪算法 预览
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作者 裴家正 黄勇 +1 位作者 董云龙 陈小龙 《通信学报》 EI CSCD 北大核心 2019年第8期102-113,共12页
针对在雷达观测下机动弱小目标的检测前跟踪(TBD)问题中,基于序贯蒙特卡洛的势均衡多伯努利检测前跟踪(SMC-CBMeMBer-TBD)算法存在目标的数目估计不准确及状态估计精度随时间下降的问题,提出了一种基于SMC-CBMeMBer前向后向平滑检测前... 针对在雷达观测下机动弱小目标的检测前跟踪(TBD)问题中,基于序贯蒙特卡洛的势均衡多伯努利检测前跟踪(SMC-CBMeMBer-TBD)算法存在目标的数目估计不准确及状态估计精度随时间下降的问题,提出了一种基于SMC-CBMeMBer前向后向平滑检测前跟踪的改进算法。该算法在预测和更新过程之间加入多目标粒子群优化算法(MOPSO),基于观测值设置适应度目标函数,使粒子集群向后验概率密度较为集中的位置分布,缓解了粒子贫乏的问题;在更新步骤之后加入平滑递归方法,利用观测值平滑滤波值,算法运算时间虽有一定延长,但获得了数目和状态估计精度的提升。仿真实验表明,与CBMeMBer-TBD方法相比,所提算法在对机动目标数目估计和目标状态估计的准确度等性能上都有所改进。 展开更多
关键词 粒子群优化 粒子滤波 势均衡多伯努利滤波 平滑 检测前跟踪
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A general, fast and robust B-spline fitting scheme for micro-line tool path under chord error constraint
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作者 BI QingZhen HUANG Jie +2 位作者 LU YaoAn ZHU LiMin DING Han 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第2期321-332,共12页
The discontinuity of linear tool path(or G01 blocks) brings about unnecessary feedrate deceleration and fluctuation during machining. To improve the continuity, the linear tool path is usually smoothed by the local tr... The discontinuity of linear tool path(or G01 blocks) brings about unnecessary feedrate deceleration and fluctuation during machining. To improve the continuity, the linear tool path is usually smoothed by the local transition method or the global fitting method. For micro-line tool path, the transition method will significantly decrease the machining efficiency and introduce feedrate fluctuation. The global fitting method cannot be directly used in the NC interpolation because the indispensable chord error checking and iterative fitting processes are computation-intensive. This paper presents a general, fast and robust B-spline fitting scheme under chord error constraint for high speed interpolation of micro-line tool path. The proposed fitting method guarantees the chord error by utilizing the strong convex hull property of B-spline curves. The knot vector and control points are initially generated by a progressive iterative approximation method and locally refined to conform to the chord error constraint by using an analytical method. The analytical approximation and refining methods avoid solving a linear system of equations that is necessary in the standard B-spline fitting method. The feasibility and efficiency of the proposed scheme has been verified via simulations and experiments. Compared with the traditional fitting method, the proposed scheme can strictly constrain the chord error and can significantly decrease the computational load. Compared with the transition scheme, the proposed scheme can significantly increase the machining efficiency for the same micro-line tool path under the same chord error tolerance. 展开更多
关键词 NC interpolation high speed machining micro-line SEGMENTS path SMOOTHING B-SPLINE FITTING
一种基于LMS滤波的单通道窄带干扰抑制平滑算法 预览
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作者 王纪东 吴治国 付睿 《舰船电子工程》 2019年第2期66-71,109共7页
信道中的窄带干扰严重影响通信的可靠性,因此必须加以抑制。针对现有方法在处理低频单音窄带干扰时的缺陷,提出了一种基于LMS滤波的单通道窄带干扰抑制平滑算法。该算法首先将受到干扰污染的信号复制为两路输入并做预处理,其次利用LMS... 信道中的窄带干扰严重影响通信的可靠性,因此必须加以抑制。针对现有方法在处理低频单音窄带干扰时的缺陷,提出了一种基于LMS滤波的单通道窄带干扰抑制平滑算法。该算法首先将受到干扰污染的信号复制为两路输入并做预处理,其次利用LMS滤波器进行窄带干扰抑制并获取滤波器响应与参考信号间的差值;最后针对低频单音干扰对输出的差值序列进行平滑处理。仿真结果表明,该算法能够对窄带单音干扰进行抑制,尤其在干扰频率较低时能够有效提升接收端信干比,提高通信质量。 展开更多
关键词 LMS算法 自适应滤波器 窄带干扰抑制 平滑处理 有限字长效应
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汽车车身拼接曲面光顺方法研究 预览
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作者 王鹏 徐家川 +2 位作者 孙凯 李迪 李波 《汽车技术》 CSCD 北大核心 2019年第2期53-57,共5页
针对车身拼接曲面光顺精度低和光顺效率低等问题,提出不同曲率半径拼接曲面的光顺方法。对于大曲率半径的拼接曲面,根据曲面与点云贴合精度调节控制顶点排序;在小曲率半径的拼接曲面中,提取拼接边线并光顺,通过裁剪的方式重新构造曲面... 针对车身拼接曲面光顺精度低和光顺效率低等问题,提出不同曲率半径拼接曲面的光顺方法。对于大曲率半径的拼接曲面,根据曲面与点云贴合精度调节控制顶点排序;在小曲率半径的拼接曲面中,提取拼接边线并光顺,通过裁剪的方式重新构造曲面。实际应用表明,根据光顺精度确定的不同曲率半径拼接曲面的光顺方法,能够快速光顺出高品质车身A级曲面。 展开更多
关键词 车身 A级曲面 拼接 光顺
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Infrared LSS-Target Detection Via Adaptive TCAIE-LGM Smoothing and Pixel-Based Background Subtraction
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作者 Yanfeng WU Yanjie WANG +2 位作者 Huiyuan LUO Boyang CHENG Haijiang SUN 《光子传感器:英文版》 EI CAS CSCD 2019年第2期179-188,共10页
Infrared small target detection is a significant and challenging topic for daily security. This paper proposes a novel model to detect LSS-target (low altitude, slow speed, and small target) under the complicated back... Infrared small target detection is a significant and challenging topic for daily security. This paper proposes a novel model to detect LSS-target (low altitude, slow speed, and small target) under the complicated background. Firstly, the fundamental constituents of an infrared image including the complexity and entropy are calculated, which are invoked as adaptive control parameters of smoothness. Secondly, the adaptive L0 gradient minimization smoothing based on texture complexity and information entropy (TCAIE-LGM) is proposed in order to remove noises and suppress low-amplitude details in infrared image abstraction. Finally, difference of Gaussian (DoG) map is incorporated into the pixel-based adaptive segmentation (PBAS) background modeling algorithm, which can differ LSS-target from the sophisticated background. Experimental results demonstrate that the proposed novel model has a high detection rate and produces fewer false alarms, which outperforms most state-of-the-art methods. 展开更多
关键词 Small target detection L0 SMOOTHING texture complexity information entropy pixel-based ADAPTIVE segmentation
Local Least Product Relative Error Estimation for Varying Coefficient Multiplicative Regression Model
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作者 Da-hai HU 《应用数学学报:英文版》 SCIE CSCD 2019年第2期274-286,共13页
In this article, we consider the varying coefficient multiplicative regression model, which is very useful to model the positive response. The criterion of least product relative error (LPRE) is extended to the varyin... In this article, we consider the varying coefficient multiplicative regression model, which is very useful to model the positive response. The criterion of least product relative error (LPRE) is extended to the varying coefficient multiplicative regression model by kernel smoothing techniques. Consistency and asymptotic normality of the proposed estimator are established. Some numerical simulations are carried out to assess the performance of the proposed estimator. As an illustration, the ethanol data is analyzed. 展开更多
关键词 VARYING COEFFICIENT MODEL MULTIPLICATIVE regression MODEL relative error KERNEL SMOOTHING
农牧交错带典型样区DEM分辨率对高程梯度的影响 预览
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作者 师动 杨勤科 朱奇峰 《东北农业大学学报》 CAS CSCD 北大核心 2019年第9期59-68,共10页
根据坡度算法基本项高程梯度p和q,选取陕西绥德和黑龙江拜泉两个样点,分析分辨率及组分对p和q影响。结果表明,p和q反映地形在x、y方向起伏程度。随平滑程度增加、采样间距增大及分辨率降低,p和q变化规律类似。随分辨率降低,图像平滑且... 根据坡度算法基本项高程梯度p和q,选取陕西绥德和黑龙江拜泉两个样点,分析分辨率及组分对p和q影响。结果表明,p和q反映地形在x、y方向起伏程度。随平滑程度增加、采样间距增大及分辨率降低,p和q变化规律类似。随分辨率降低,图像平滑且产生信息损失,方差、值域变小,分布集中。分辨率及组分对p和q影响排序为:分辨率>平滑程度>采样间距。 展开更多
关键词 高程梯度 DEM分辨率 平滑程度 采样间距 农牧交错带
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A Study on Precipitation Products with High Resolution in Anhui Province Based on Thin Plate Smoothing Spline 预览
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作者 Li Jun Wen Huayang Chen Fengjiao 《气象与环境研究:英文版》 CAS 2019年第3期41-47,共7页
In order to achieve refined precipitation grid data with high accuracy and high spatial resolution,hourly precipitation grid dataset with 1 km spatial resolution in Anhui Province from May to September (in the rainy s... In order to achieve refined precipitation grid data with high accuracy and high spatial resolution,hourly precipitation grid dataset with 1 km spatial resolution in Anhui Province from May to September (in the rainy season) in 2016 and from August 2017 to July 2018 was established based on thin plate smoothing spline (TPS),which meets the needs of climate change research and meteorological disaster risk assessment.The interpolation errors were then analyzed.The grid precipitation product obtained based on thin plate smoothing spline,CLDAS-FAST and CLDAS-FRT were evaluated.The results show that the interpolated values of hourly precipitation by thin plate smoothing spline are close to the observed values in the rainy season of 2016.The errors are generally below 0.9 mm/h.However,the errors of precipitation in the mountainous areas of eastern Huaibei and western Anhui are above 1.2 mm/h.On monthly scale,the errors in June and July are the largest,and the proportion of absolute values of the errors ≥2 mm/h is up to 2.0% in June and 2.2% in July.The errors in September are the smallest,and the proportion of absolute values of the errors ≥2 mm/h is only 0.6%.The root mean square (RMSE) is only 0.37 mm/h,and the correlation coefficient (COR) is 0.93.The interpolation accuracy of CLDAS-FRT is the highest,with the smallest RMSE (0.65 mm/h) and mean error ( ME =0.01 mm/h),and the largest COR (0.81).The accuracy of the precipitation product obtained by thin plate smoothing spline interpolation is close to that of CLDAS-FAST.Its RMSE is up to 0.80 mm/h,and its ME is only -0.01 mm/h.Its COR is 0.73,but its bias (BIAS) is up to 1.06 mm/h. 展开更多
关键词 PRECIPITATION High RESOLUTION THIN plate SMOOTHING SPLINE
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Testing the fidelity of Gaussian processes for cosmography
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作者 周欢 李正祥 《中国物理C:英文版》 SCIE CAS CSCD 2019年第3期99-106,共8页
The dependence of implications from observations on cosmological models is an intractable problem not only in cosmology, but also in astrophysics. Gaussian processes(GPs), a powerful nonlinear interpolating tool witho... The dependence of implications from observations on cosmological models is an intractable problem not only in cosmology, but also in astrophysics. Gaussian processes(GPs), a powerful nonlinear interpolating tool without assuming a model or parametrization, have been widely used to directly reconstruct functions from observational data(e.g., expansion rate and distance measurements) for cosmography. However, the fidelity of this reconstructing method has never been checked. In this study, we test the fidelity of GPs for cosmography by mocking observational data sets comprising different number of events with various uncertainty levels. These factors are of great importance for the fidelity of reconstruction. That is, for the expansion rate measurements, GPs are valid for reconstructing the functions of the Hubble parameter versus redshift when the number of observed events is as many as 256 and the uncertainty of the data is ~3%. Moreover, the distance-redshift relation reconstructed from the observations of the upcoming Dark Energy Survey type la supernovae is credible. 展开更多
关键词 EXPANSION RATE RECONSTRUCTION GAUSSIAN process SMOOTHING
A Study on Spatial Interpolation of Temperature in Anhui Province Based on ANUSPLIN 预览
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作者 Wen Huayang Chen Fengjiao +2 位作者 Li Jun Qiu Kangjun Wang Gen 《气象与环境研究:英文版》 CAS 2019年第2期51-55,60共6页
To achieve refined temperature grid data with high accuracy and high spatial resolution,hourly temperature grid dataset with spatial resolution of 1 km in Anhui Province from January to December in 2016 was establishe... To achieve refined temperature grid data with high accuracy and high spatial resolution,hourly temperature grid dataset with spatial resolution of 1 km in Anhui Province from January to December in 2016 was established using the ANUSPLIN thin plate spline algorithm,which meets the needs of climate change research and meteorological disaster risk assessment. And the interpolation error was analyzed. The results show that the interpolated values of hourly temperature by ANUSPLIN are close to the observed values in 2016. The error is generally below 1. 5 ℃,and the root mean square error is 0. 937 6 ℃. On monthly scale,the interpolated values of hourly temperature by ANUSPLIN are also close to the observed values.In October,November,June and May,the interpolation accuracy is the highest,and the proportion of absolute error of hourly temperature lower than 2 ℃ is up to 99%,97. 4%,98. 1% and 97. 4% respectively. In February,March,August and December,the interpolation accuracy is the lowest,and the proportion of absolute error higher than 2 ℃ is 8. 1%,5. 3%,4. 1% and 4. 2% respectively. Due to the effect of complex topography in Anhui,the interpolation accuracy is the lowest in the mountainous areas of southern and western Anhui,and the interpolation error in these regions even exceeds 1. 5 ℃ annually and 1. 8 ℃ monthly. 展开更多
关键词 TEMPERATURE INTERPOLATION ANUSPLIN THIN plate SMOOTHING SPLINE
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基于三次样条曲线的码垛机器人平滑轨迹规划方法 预览 被引量:2
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作者 张玲 《高技术通讯》 北大核心 2018年第1期78-82,共5页
以混联式圆柱坐标码垛机器人为对象,研究了高速码垛机器人在关节空间内快速平稳的轨迹规划问题。首先应用三次样条曲线对机器人轨迹进行规划,其次以路径点的逼近程度与轨迹曲线的参数连续性为参考,建立了机器人平滑轨迹优化模型,得到了... 以混联式圆柱坐标码垛机器人为对象,研究了高速码垛机器人在关节空间内快速平稳的轨迹规划问题。首先应用三次样条曲线对机器人轨迹进行规划,其次以路径点的逼近程度与轨迹曲线的参数连续性为参考,建立了机器人平滑轨迹优化模型,得到了基于三次样条曲线的码垛机器人平滑轨迹。仿真结果表明,给定不同的曲线最大拟合误差,机器人的运动轨迹优化效果不同,验证了该轨迹规划方法能够兼顾码垛机器人的运动平稳性与轨迹平滑连续的控制要求,减小其在加、减速过程中产生的机械振动。 展开更多
关键词 轨迹规划 三次样条曲线 平滑性 码垛机器人
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