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ON AMODIFIED NEWTON'S METHOD AND CONVERGENCE
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作者 韩丹夫 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 1997年第1期107-112,共6页
In this paper we discuss the convergence of a modified Newton’s method presented by A. Ostrowski [1] and J.F. Traub [2], which has quadratic convergence order but reduces one evaluation of the derivative at every two... In this paper we discuss the convergence of a modified Newton’s method presented by A. Ostrowski [1] and J.F. Traub [2], which has quadratic convergence order but reduces one evaluation of the derivative at every two steps compared with Newton’s method. A convergence theorem is established by using a weak condition a≤3-2(2<sup>1/2</sup>) and a sharp error estimate is given about the iterative sequence. 展开更多
关键词 modified Newton’s method CONVERGENCE majurant method ERROR estimate.
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Symmetry and Exact Solutions of (2+1)-Dimensional Generalized Sasa-Satsuma Equation via a Modified Direct Method
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作者 LU Chang-Cheng CHEN Yong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第6期973-978,共6页
In this paper, first, we employ classic Lie symmetry groups approach to obtain the Lie symmetry groupsof the well-known (2+1)-dimensional Generalized Sasa-Satsuma (GSS) equation. Second, based on a modified directmeth... In this paper, first, we employ classic Lie symmetry groups approach to obtain the Lie symmetry groupsof the well-known (2+1)-dimensional Generalized Sasa-Satsuma (GSS) equation. Second, based on a modified directmethod proposed by Lou [J. Phys. A: Math. Gen. 38 (2005) L129], more general symmetry groups are obtained andthe relationship between the new solution and known solution is set up. At the same time, the Lie symmetry groupsobtained are only special cases of the more general symmetry groups. At last, some exact solutions of GSS equationsare constructed by the relationship obtained in the paper between the new solution and known solution. 展开更多
关键词 classic Lie symmetry groups approach modified CK's direct method generalized sasa-satsuma equation
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Nonlinear constrained optimization using the flexible tolerance method hybridized with different unconstrained methods 被引量:1
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作者 Alice Medeiros Lima Antonio Jose Goncalves Cruz Wu Hong Kwong 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第4期442-452,共11页
This paper proposes the use of the flexible tolerance method(FTM) modified with scaling of variables and hybridized with different unconstrained optimization methods to solve real constrained optimization problems.The... This paper proposes the use of the flexible tolerance method(FTM) modified with scaling of variables and hybridized with different unconstrained optimization methods to solve real constrained optimization problems.The benchmark problems used to analyze the performance of the methods were taken from G-Suite functions.The original method(FTM) and other four proposed methods:(i) FTM with scaling of variables(FTMS),(ii) FTMS hybridized with BFGS(FTMS-BFGS),(iii) FTMS hybridized with modified Powell's method(FTMS-Powell)and(iv) FTMS hybridized with PSO(FTMS-PSO), were implemented. The success rates of the methods were 80%,100%, 75%, 95% and 85%, for FTM, FTMS, FTMS-BFGS, FTMS-Powell and FTMS-PSO, respectively. Numerical experiments including real constrained problems indicated that FTMS gave the best performance, followed by FTMSPowell and FTMS-PSO. Despite the inferior performance compared to FTMS and FTMS-Powell, the FTMS-PSO method presented some advantages since good different initial points could be obtained, which allow exploring different routes through the solution space and to escape from local optima. The proposed methods proved to be an effective way of improving the performance of the original FTM. 展开更多
关键词 Flexible tolerance method modified Powell’s method BFGs PsO scaling HYBRIDIZATION
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Application of the Improved Kudryashov Method to Solve the Fractional Nonlinear Partial Differential Equations 被引量:2
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作者 Md. Abdus Salam Umme Habiba 《Journal of Applied Mathematics and Physics》 2019年第4期912-920,共9页
Our purpose of this paper is to apply the improved Kudryashov method for solving various types of nonlinear fractional partial differential equations. As an application, the time-space fractional Korteweg-de Vries-Bur... Our purpose of this paper is to apply the improved Kudryashov method for solving various types of nonlinear fractional partial differential equations. As an application, the time-space fractional Korteweg-de Vries-Burger (KdV-Burger) equation is solved using this method and we get some new travelling wave solutions. To acquire our purpose a complex transformation has been also used to reduce nonlinear fractional partial differential equations to nonlinear ordinary differential equations of integer order, in the sense of the Jumarie’s modified Riemann-Liouville derivative. Afterwards, the improved Kudryashov method is implemented and we get our required reliable solutions where the results are justified by mathematical software Maple-13. 展开更多
关键词 IMPROVED Kudryashov method Time-space FRACTIONAL KdV-Burger Equation TRAVELLING Wave solutions Jumarie’s modified Riemann-Liouville Derivative
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Stability Control of Stretch-Twist-Fold Flow by Using Numerical Methods
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作者 Shahab Ud-Din Khan Yonglu Shu Salah Ud-Din Khan 《World Journal of Mechanics》 2012年第6期334-338,共5页
In this study, the multistep method is applied to the STF system. This method has been tested on the STF system, which is a three-dimensional system of ODE with quadratic nonlinearities. A computer based Matlab progra... In this study, the multistep method is applied to the STF system. This method has been tested on the STF system, which is a three-dimensional system of ODE with quadratic nonlinearities. A computer based Matlab program has been developed in order to solve the STF system. Stable and unstable position of the system has been analyzed graphically and finally a comparison as well as accuracy between two-step sizes with detail. Newton’s method has been applied to show the best convergence of this system. 展开更多
关键词 sTF system CHAOs modified method Fixed Point ITERATION method Newton’s method
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基于改进的D-S证据理论在设备故障诊断中的应用 被引量:7
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作者 齐占伟 辜承林 《海军工程大学学报》 CAS 北大核心 2008年第1期60-64,共5页
多传感器、多手段检测的信息融合技术在设备检测中的应用日益广泛,而常用的基于D-S证据理论的融合技术除了没有给出可信度的分配方法外,融合结果上还有很多不足之处。探讨了可信度的分配问题,提出了几种改进的融合方法,较好地解决了证... 多传感器、多手段检测的信息融合技术在设备检测中的应用日益广泛,而常用的基于D-S证据理论的融合技术除了没有给出可信度的分配方法外,融合结果上还有很多不足之处。探讨了可信度的分配问题,提出了几种改进的融合方法,较好地解决了证据冲突时的否定性、积化性和敏感性问题。 展开更多
关键词 D-s证据 改进融合方法 故障诊断
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国际汇率分形特征的实证研究:修正的R/S分析 被引量:8
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作者 宋耀 田华 《河北大学学报(哲学社会科学版)》 CSSCI 2004年第4期93-96,共4页
首先对修正的R/S方法进行了介绍;然后通过实证研究指出国际汇率变化不服从正态分布并且汇率波动的相关性不显著;最后运用修正的R/S方法实证研究了国际汇率波动的分形特征,与使用传统R/S方法所得结论不同,通过实证说明外汇波动并不存在... 首先对修正的R/S方法进行了介绍;然后通过实证研究指出国际汇率变化不服从正态分布并且汇率波动的相关性不显著;最后运用修正的R/S方法实证研究了国际汇率波动的分形特征,与使用传统R/S方法所得结论不同,通过实证说明外汇波动并不存在明显的长程相关性。 展开更多
关键词 汇率 分形 长程相关 修正R/s分析
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耦合Burgers方程的对称群和新精确解 被引量:1
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作者 杨立娟 杨琼芬 杜先云 《四川师范大学学报(自然科学版)》 CAS CSCD 北大核心 2014年第1期81-85,共5页
利用推广的CK直接方法,求出了耦合Burgers方程的一般对称群,建立了方程新旧解之间的关系,进一步利用对称求得了耦合Burgers方程的不变量和若干约化,通过约化方程求得耦合Burgers方程大量新的精确解,包括有理函数解、三角函数解和双曲函... 利用推广的CK直接方法,求出了耦合Burgers方程的一般对称群,建立了方程新旧解之间的关系,进一步利用对称求得了耦合Burgers方程的不变量和若干约化,通过约化方程求得耦合Burgers方程大量新的精确解,包括有理函数解、三角函数解和双曲函数解. 展开更多
关键词 耦合Burgers方程 推广的CK直接方法 精确解 对称群 约化
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Adomian分解法在完全非线性S-G方程中的运用
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作者 王玉春 《成都信息工程学院学报》 2009年第1期91-98,共8页
为分析具有高非线性强度下的偏微分方程的初值问题,简化变量分离等方法带来的繁杂计算,研究了一类完全非线性Sine-Gordon方程以及它的近似方程(在|up|很小的情况下),经过适当的函数变换,运用改进的Ado-mian分解法解决了一些特殊情况下... 为分析具有高非线性强度下的偏微分方程的初值问题,简化变量分离等方法带来的繁杂计算,研究了一类完全非线性Sine-Gordon方程以及它的近似方程(在|up|很小的情况下),经过适当的函数变换,运用改进的Ado-mian分解法解决了一些特殊情况下它们的初值问题,结合Talyor级数展开式,得到了一些精确解:扭结解(kink)、紧孤子解(compacton)、多重紧孤子解、compacton-kink解。另外运用线性化的方法结合不同形式的解得到它们一些更加丰富的新形式的精确解。 展开更多
关键词 完全非线性sine-Gordon方程 近似s-G方程 改进的Adomian分解法 ADOMIAN多项式 COMPACTON解
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Symmetry Groups and New Exact Solutions to (2+1)-Dimensional Variable Coefficient Canonical Generalized KP Equation 被引量:7
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作者 ZHANG Li-Hua LIU Xi-Qiang BAI Cheng-Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第3X期405-410,共6页
In this paper, the modified CK's direct method to find symmetry groups of nonlinear partial differential equation is extended to (2+1)-dimensional variable coeffficient canonical generalized KP (VCCGKP) equation... In this paper, the modified CK's direct method to find symmetry groups of nonlinear partial differential equation is extended to (2+1)-dimensional variable coeffficient canonical generalized KP (VCCGKP) equation. As a result, symmetry groups, Lie point symmetry group and Lie symmetry for the VCCGKP equation are obtained. In fact, the Lie point symmetry group coincides with that obtained by the standard Lie group approach. Applying the given Lie symmetry, we obtain five types of similarity reductions and a lot of new exact solutions, including hyperbolic function solutions, triangular periodic solutions, Jacobi elliptic function solutions and rational solutions, for the VCCGKP equation. 展开更多
关键词 (2+1)-dimensional variable coefficient canonical generalized KP (VCCGKP) equation modified CK's'direct method symmetry groups Lie symmetry similarity reductions new exact solutions
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Symplocosionosides A-C, Three Megastigmane Glycosides, a Neolignan Glucoside, and Symplocosins A and B, Two Triterpene Glycosyl Esters from the Leaves of <i>Symplocos cochinchinensis</i>var. <i>Philippinensis</i> 被引量:3
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作者 Wen-Hu Cai Katsuyoshi Matsunami +1 位作者 Hideaki Otsuka Yoshio Takeda 《American Journal of Plant Sciences》 2011年第4期609-618,共10页
From the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Symplocos cochinchinensis var. philippinensis, 12 compounds were isolated. Spectroscopic analyses of compounds 1 - 3 established their structures to ... From the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Symplocos cochinchinensis var. philippinensis, 12 compounds were isolated. Spectroscopic analyses of compounds 1 - 3 established their structures to be megastig-mane glycosides, named symplocosionosides A-C. The absolute structure of 1 was determined by the modified Mosher’s method. Compound 4 was found to be a neolignan glucoside and named symplocosneolignan. The structures of com-pounds 5 and 6, named symplocosins A and B, were elucidated to be the saponins of hederagenin sugar esters. The structures of the remaining known compounds (7 - 12) were identified by comparison of spectroscopic data with those reported in the literature. 展开更多
关键词 sYMPLOCOs cochinchinensis var. Philippinensis symplocaceae MEGAsTIGMANE Glycoside NEOLIGNAN Glucoside TRITERPENE Glycosyl Ester modified Mosher’s method
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Synthesis and Determination of Absolute Configuration of a Divergent Polyhydroxy Enyne Compound
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作者 Zhi Jie XUE Yuan Chao LI 《Chinese Chemical Letters》 SCIE CAS CSCD 2005年第12期1569-1572,共4页
Polyhydroxy enyne compound (+)-(1'S, 2R, 3S, 5S, 6S)-5,6-dimethoxy-5, 6-dimethyl- 2-(1'-hydroxylpropyl-2-ne)-3-vinyl-l,4-dioxane has been synthesized from D-(-)-tartaric acid. A new chiral center was establ... Polyhydroxy enyne compound (+)-(1'S, 2R, 3S, 5S, 6S)-5,6-dimethoxy-5, 6-dimethyl- 2-(1'-hydroxylpropyl-2-ne)-3-vinyl-l,4-dioxane has been synthesized from D-(-)-tartaric acid. A new chiral center was established by nucleophilic addition with 87% de. The modified Mosher's method was employed to confirm the absolute configuration of 17, which assigned the S-configuration at the new chiral center. 展开更多
关键词 Tartaric acid enyne compound nucleophilic addition modified Mosher's method
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Symmetry Groups and New Exact Solutions of(2+1)-Dimensional Dispersive Long-Wave Equations
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作者 TIAN Ying-Hui CHEN Han-Lin LIU Xi-Qiang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第5期781-784,共4页
Using the modified CK's direct method, we derive a symmetry group theorem of (2+1)-dimensional dispersive long-wave equations. Based upon the theorem, Lie point symmetry groups and new exact solutions of (2+1)-... Using the modified CK's direct method, we derive a symmetry group theorem of (2+1)-dimensional dispersive long-wave equations. Based upon the theorem, Lie point symmetry groups and new exact solutions of (2+1)- dimensional dispersive long-wave equations are obtained. 展开更多
关键词 (2+1)-dimensional dispersive long-wave equations exact solution modified CK's direct method symmetry groups
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Bayesian Estimations with Fuzzy Data to Estimation Inverse Rayleigh Scale Parameter
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作者 Shurooq Ahmed Kareem AL-Sultany 《Open Journal of Applied Sciences》 2019年第8期673-681,共9页
In this paper, Bayesian computational method is used to estimate inverse Rayleigh Scale parameter with fuzzy data. Based on imprecision data, the Bayes estimates cannot be obtained in explicit form. Therefore, we prov... In this paper, Bayesian computational method is used to estimate inverse Rayleigh Scale parameter with fuzzy data. Based on imprecision data, the Bayes estimates cannot be obtained in explicit form. Therefore, we provide Tierney and Kadane’s approximation to compute the Bayes estimates of the scale parameter under Square error and Precautionary loss function using Non-informative Jefferys Prior. Also, we provide compared numerically through Monte-Carlo simulation study to obtained estimates of the scale parameter in terms of mean squared error values. 展开更多
关键词 INVERsE RAYLEIGH DIsTRIBUTION IMPRECIsION Data modified NEWTON method Tierney and Kadane’s APPROXIMATION
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Modified Kadomtsev-Petviashvili Equation in (3+1) Dimensions:Multiple Front-Wave Solutions
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作者 A.M.Wazwaz XU Gui-Qiong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2015年第6期727-730,共4页
A modified Kadomtsev-Petviashvili (mKP) equation in (3+1) dimensions is presented. We reveal multiple front-waves solutions for this higher-dimensional developed equation, and multiple singular front-wave solutio... A modified Kadomtsev-Petviashvili (mKP) equation in (3+1) dimensions is presented. We reveal multiple front-waves solutions for this higher-dimensional developed equation, and multiple singular front-wave solutions as well. The constraints on the coefficients of the spatial variables, that assure the existence of these multiple front-wave solutions are investigated. We also show that this equation falls the Painleve test, and we conclude that it is not integrable in the sense of possessing the Painleve property, although it gives multiple front-wave solutions. 展开更多
关键词 modified Kadomtsev-Petviashvili equation multiple front-waves solutions Hirota's method
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改进的人工鱼群算法和Powell法结合的医学图像配准 被引量:21
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作者 赵海峰 姚丽莎 罗斌 《西安交通大学学报》 EI CAS CSCD 北大核心 2011年第4期46-52,共7页
针对目前基于互信息图像配准的局部极值问题,提出了一种改进的人工鱼群算法和Powell算法结合的多分辨率医学图像配准算法.该算法采用新的相似性测度方法即归一化模糊加权互信息和归一化局部能量加权匹配度,利用多分辨率策略采用HPV插值... 针对目前基于互信息图像配准的局部极值问题,提出了一种改进的人工鱼群算法和Powell算法结合的多分辨率医学图像配准算法.该算法采用新的相似性测度方法即归一化模糊加权互信息和归一化局部能量加权匹配度,利用多分辨率策略采用HPV插值,并采用改进的人工鱼群算法结合Powell算法完成医学图像的配准.采用改进的人工鱼群算法在图像的最低分辨率上进行全局优化,以全局最优值为初始值,结合Powell算法完成图像配准.这不仅基本解决了互信息函数和Powell算法的局部极值问题,还减少了数据的处理量,加快了配准速度.实验结果表明,文中算法与其他经典的配准算法相比,提高了配准的精确度和性能. 展开更多
关键词 图像配准 改进的人工鱼群算法 Powell法 多分辨率
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超声提取-改进BCR法测定PM_(2.5)中6种重金属元素的化学形态 被引量:6
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作者 杨华 吴宇峰 +2 位作者 王静 闫荣馨 张永刚 《理化检验(化学分册)》 CAS CSCD 北大核心 2015年第8期1154-1158,共5页
应用改进的BCR法对大气微颗粒物(PM2.5)进行分析,用超声法代替原来的机械振荡法,对所采得的微颗粒物样品中6种重金属元素(铜、锌、铅、镉、镍、铬)的4种化学形态(酸可交换态F1,可还原态F2,可氧化态F3及残渣态F4)进行分别提取,所得各形... 应用改进的BCR法对大气微颗粒物(PM2.5)进行分析,用超声法代替原来的机械振荡法,对所采得的微颗粒物样品中6种重金属元素(铜、锌、铅、镉、镍、铬)的4种化学形态(酸可交换态F1,可还原态F2,可氧化态F3及残渣态F4)进行分别提取,所得各形态溶液中的金属元素含量用电感耦合等离子体质谱法测定。结果表明:超声提取法的提取时间仅为30min(对F1及F2)和20min(对F3),而原方法需16h;而且超声提取的效率较高,是原方法的89.5%~133%;6种元素的化学形态测定结果的相对标准偏差(n=8)均小于25%。此外,样品中的元素形态总量(ng·m-3)与元素全量(ng·m-3)之间的偏差在-30.7%^-11.5%之间。 展开更多
关键词 超声提取 改进BCR法 PM2.5微颗粒物 重金属元素 化学形态
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厚截面复合材料局域孔隙超声检测方法 被引量:8
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作者 陈越超 周晓军 +2 位作者 杨辰龙 李钊 郑慧峰 《农业机械学报》 EI CAS CSCD 北大核心 2015年第6期372-378,共7页
采用超声脉冲反射法对厚截面复合材料局域孔隙缺陷进行检测,提取超声背散射信号进行分析。结果表明,在材料近表面区域可能产生共振结构噪声,孔隙会导致结构噪声频率降低、幅值减小;在远表面区域的背散射信号恢复正常状态,孔隙则会导致... 采用超声脉冲反射法对厚截面复合材料局域孔隙缺陷进行检测,提取超声背散射信号进行分析。结果表明,在材料近表面区域可能产生共振结构噪声,孔隙会导致结构噪声频率降低、幅值减小;在远表面区域的背散射信号恢复正常状态,孔隙则会导致较小幅值回波的出现。在此基础上提出了基于背散射信号处理的局域孔隙识别方法。对近表面信号使用改进S变换生成时频系数矩阵,再计算信号主频极小值及增益来识别孔隙。对远表面信号则先进行小波变换模极大值去噪,再使用改进S变换生成时频系数矩阵,最后计算信号主频极大值及增益来识别孔隙。对厚截面复合材料平板和曲面试块的实验表明,使用该信号处理方法可以有效识别厚截面复合材料局域孔隙缺陷。 展开更多
关键词 厚截面复合材料 超声脉冲反射法 背散射信号 改进s变换 小波模极大
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改进的WHITTAKER方法:一种多尺度的嵌套式植物多样性取样方法 被引量:5
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作者 梁继业 于春堂 杨晓晖 《水土保持研究》 CSCD 北大核心 2007年第1期226-229,233,共5页
在分析了目前植物多样性研究中取样技术存在的一些问题之后,着重介绍了改进的Whittaker取样方法。Whittaker方法是一种标准的多尺度嵌套式长方形取样技术,而改进的Whittaker方法是对这种方法的进一步完善和充实。这种取样方法的应用将... 在分析了目前植物多样性研究中取样技术存在的一些问题之后,着重介绍了改进的Whittaker取样方法。Whittaker方法是一种标准的多尺度嵌套式长方形取样技术,而改进的Whittaker方法是对这种方法的进一步完善和充实。这种取样方法的应用将有助于降低空间尺度对物种丰富度的影响,使之更为有效地量度和预测不同生态系统的物种丰富度,特别是对空间异质性较大的生态系统更具有较高的实用价值。 展开更多
关键词 Whittaker取样方法 改进的Whittaker取样方法 生物多样性 空间尺度
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一类离散时间代数Riccati矩阵方程对称解的双迭代算法 被引量:3
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作者 张凯院 宁倩芝 牛婷婷 《计算机工程与科学》 CSCD 北大核心 2015年第2期329-334,共6页
利用逆矩阵的Neumann级数形式,将在线性二次优化问题中遇到的含未知矩阵之逆的离散时间代数Riccati矩阵方程(DTARME)转化为高次多项式矩阵方程,然后采用牛顿算法求高次多项式矩阵方程的对称解,并采用修正共轭梯度法求由牛顿算法每一步... 利用逆矩阵的Neumann级数形式,将在线性二次优化问题中遇到的含未知矩阵之逆的离散时间代数Riccati矩阵方程(DTARME)转化为高次多项式矩阵方程,然后采用牛顿算法求高次多项式矩阵方程的对称解,并采用修正共轭梯度法求由牛顿算法每一步迭代计算导出的线性矩阵方程的对称解或者对称最小二乘解,建立求DTARME的对称解的双迭代算法。双迭代算法仅要求DTARME有对称解,不要求它的对称解唯一,也不对它的系数矩阵做附加限定。数值算例表明双迭代算法是有效的。 展开更多
关键词 Riccati矩阵方程 对称解 牛顿算法 修正共轭梯度法 双迭代算法
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