期刊文献+
共找到52篇文章
< 1 2 3 >
每页显示 20 50 100
基于模糊理论的混凝土热力学参数识别方法 被引量:9
1
作者 李守巨 刘迎曦 《岩土力学》 EI CAS CSCD 北大核心 2004年第4期570-573,共4页
根据混凝土内部温度观测数据,建立了基于模糊理论的混凝土热力学参数识别方法。根据观测点的温度观测数据的误差特性,建立了模糊优化的目标函数。将热传导反问题作为非线性优化问题处理,然后采用BFGS方法求解。由于温度观测误差的随机特... 根据混凝土内部温度观测数据,建立了基于模糊理论的混凝土热力学参数识别方法。根据观测点的温度观测数据的误差特性,建立了模糊优化的目标函数。将热传导反问题作为非线性优化问题处理,然后采用BFGS方法求解。由于温度观测误差的随机特性,分析了混凝土热力学参数识别结果的统计特性。数值计算结果表明,在考虑到温度观测误差的条件下,所建立的参数反演方法能够有效地识别出混凝土的热力学参数。 展开更多
关键词 反问题 混凝土热力学参数 参数识别 隶属函数 正态分布
下载PDF
微分中值定理与积分中值定理的逆定理 被引量:4
2
作者 张兴龙 王丽霞 《江苏理工大学学报(自然科学版)》 1999年第1期91-94,共4页
给出并论证了微分中值定理(Lagrange中值定理和Cauchy中值定理)及积分第一、第二中值定理在某种条件下的逆定理.
关键词 中值定理 逆定理 微分中值定理 积分中值定理
下载PDF
A Certain Subclass of Analytic Functions with Bounded Positive Real Part 被引量:2
3
作者 Young Jae Sim Oh Sang Kwon 《Advances in Pure Mathematics》 2013年第4期409-414,共6页
For real numbers α and β such that 0≤α<1<β, we denote by T(α,β) the class of normalized analytic functions which satisfy , where U denotes the open unit disk. We find some relationships involving function... For real numbers α and β such that 0≤α<1<β, we denote by T(α,β) the class of normalized analytic functions which satisfy , where U denotes the open unit disk. We find some relationships involving functions in the class T(α,β). And we estimate the bounds of coefficients and solve Fekete-Szego problem for functions in this class. Furthermore, we investigate the bounds of initial coefficients of inverse functions or bi-univalent functions. 展开更多
关键词 functions of Bounded Positive Real Part Fekete-Szego Problem inverse functions Bi-Univalent functions
下载PDF
Some Universal Properties of the Green’s Functions Associated with the Wave Equation in Bounded Partially-Homogeneous Domains and Their Use in Acoustic Tomography
4
作者 Mithat Idemen 《Applied Mathematics》 2017年第4期483-499,共17页
Direct and inverse scattering problems connected with the wave equation in non-homogeneous bounded domains constitute challenging actual subjects for both mathematicians and engineers. Among them one can mention, for ... Direct and inverse scattering problems connected with the wave equation in non-homogeneous bounded domains constitute challenging actual subjects for both mathematicians and engineers. Among them one can mention, for example, inverse source problems in seismology, nondestructive archeological probing, mine prospecting, inverse initial-value problems in acoustic tomography, etc. In spite of its crucial importance, almost all of the available rigorous investigations concern the case of unbounded simple domains such as layered planar or cylindrical or spherical structures. The main reason for the lack of the works related to non-homogeneous bounded structures is the extreme complexity of the explicit expressions of the Green’s functions. The aim of the present work consists in discovering some universal properties of the Green’s functions in question, which reduce enormously the difficulties arising in various applications. The universality mentioned here means that the properties are not depend on the geometrical and physical properties of the configuration. To this end one considers first the case when the domain is partially-homogeneous. Then the results are generalized to the most general case. To show the importance of the universal properties in question, they are applied to an inverse initial-value problem connected with photo-acoustic tomography. 展开更多
关键词 Green’s functions inverse Source PROBLEM inverse Initial-Value PROBLEM TOMOGRAPHY Photo-Acoustic TOMOGRAPHY Thermo-Acoustic TOMOGRAPHY Wave Equation
下载PDF
蚁群算法求解双弹性模量桁架结构反问题 被引量:3
5
作者 杨海天 张晓月 +1 位作者 赵潇 何宜谦 《工程力学》 EI CSCD 北大核心 2010年第10期155-161,共7页
利用光滑函数和有限元技术,建立了求解弹性双模量桁架结构的正问题数值模型,推导了敏度计算公式,并采用Newton-Raphson算法进行求解,在正问题建模的基础上,利用蚁群算法对拉压弹性模量进行识别,并探讨了参数取值范围和数据噪音对识别结... 利用光滑函数和有限元技术,建立了求解弹性双模量桁架结构的正问题数值模型,推导了敏度计算公式,并采用Newton-Raphson算法进行求解,在正问题建模的基础上,利用蚁群算法对拉压弹性模量进行识别,并探讨了参数取值范围和数据噪音对识别结果的影响,计算结果表明蚁群算法可有效地求解不同模量桁架反问题。 展开更多
关键词 拉压双弹性模量 反问题 光滑函数 蚁群算法 桁架
原文传递
两级敏度分析求解双弹性模量桁架结构反问题 被引量:2
6
作者 杨海天 张晓月 何宜谦 《固体力学学报》 CAS CSCD 北大核心 2010年第2期198-204,共7页
利用光滑函数和有限元技术,建立了求解双弹性模量桁架结构正问题的数值模型,可方便推导刚度对位移、位移对弹性模量的敏度计算公式.在此基础上,发展了一种基于两级敏度分析求解双弹性模量桁架结构反问题的数值模型,正问题与反问题分别采... 利用光滑函数和有限元技术,建立了求解双弹性模量桁架结构正问题的数值模型,可方便推导刚度对位移、位移对弹性模量的敏度计算公式.在此基础上,发展了一种基于两级敏度分析求解双弹性模量桁架结构反问题的数值模型,正问题与反问题分别采用Newton-Raphson与Gauss-Newton算法进行求解,数值验证给出了令人满意的结果,并考虑了数据噪音的影响. 展开更多
关键词 拉压双弹性模量 反问题 光滑函数 两级敏度分析 桁架
下载PDF
On Algebraic Immunity of Trace Inverse Functions on Finite Fields of Characteristic Two 被引量:1
7
作者 FENG Xiutao GONG Guang 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2016年第1期272-288,共17页
The trace inverse functions Tr(λx^(-1)) over the finite field F_(2~n) are a class of very important Boolean functions and are used in many stream ciphers such as SFINKS,RAKAPOSHI,the simple counter stream cipher(SCSC... The trace inverse functions Tr(λx^(-1)) over the finite field F_(2~n) are a class of very important Boolean functions and are used in many stream ciphers such as SFINKS,RAKAPOSHI,the simple counter stream cipher(SCSC) presented by Si W and Ding C(2012),etc.In order to evaluate the security of those ciphers in resistance to(fast) algebraic attacks,the authors need to characterize algebraic properties of Tr(λx^(-1)).However,currently only some bounds on algebraic immunity of Tr(λx^(-1)) are given in the public literature,for example,the NGG upper bound and the Bayev lower bound,etc.This paper gives the exact value of the algebraic immunity of Tr(λx^(-1)) over F_(2~n),that is,AI(Tr(λx^(-1))) =[2n^(1/2)]- 2,where n ≥ 2,A ∈ F_(2~n) and λ≠ 0,which shows that Dalai's conjecture on the algebraic immunity of Tr(λx^(-1)) is correct.What is more,the authors demonstrate some weak properties of Tr(λx^(-1)) against fast algebraic attacks. 展开更多
关键词 Algebraic immunity boolean functions fast algebraic attacks trace inverse functions
原文传递
反三角函数是怎样产生的?
8
作者 聂学建 《职大学报》 2014年第2期71-72,共2页
三角函数学了正弦、余弦和正切,没学余切、正割和余割;更没学反三角函数了!这就是今年某些大专新生在初等数学方面的薄弱之处;读懂本文后,新生们一定能有所弥补,在进校后的高等数学学习中扎实地迈进一大步。
关键词 函数 反函数 三角函数 反三角函数
下载PDF
Optimal obstacle avoidance via distributed consensus algorithms with communication delay
9
作者 Jingliang Sun Chunsheng Liu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第6期1272-1282,共11页
A consensus problem of multi-agent system subject to the communication delay with fixed and switching topologies as well as optimal obstacle avoidance is investigated. An innovative non-quadratic obstacle avoidance co... A consensus problem of multi-agent system subject to the communication delay with fixed and switching topologies as well as optimal obstacle avoidance is investigated. An innovative non-quadratic obstacle avoidance cost function is designed from an inverse optimal control perspective and a novel dynamic potential field whose vectors are rotating around the obstacle is introduced to avoid obstacles. The asymptotic stability condition of dynamical networks based on the Lyapunov-Krasovskii function is obtained via a linear matrix inequality (LMI) formulation. Finally, numerical examples are presented to show the effectiveness of the proposed theoretical results. © 2016 Beijing Institute of Aerospace Information. 展开更多
关键词 Asymptotic stability Collision avoidance Cost functions inverse problems Linear matrix inequalities
下载PDF
A General Algorithm for Biorthogonal Functions and Performance Analysis of Biorthogonal Scramble Modulation System
10
作者 Yueyun Chen Zhenhui Tan 《Wireless Sensor Network》 2010年第3期199-205,共7页
Applying the theorems of Mobius inverse and Dirichlet inverse, a general algorithm to obtain biorthogonal functions based on generalized Fourier series analysis is introduced. In the algorithm, the orthogonal function... Applying the theorems of Mobius inverse and Dirichlet inverse, a general algorithm to obtain biorthogonal functions based on generalized Fourier series analysis is introduced. In the algorithm, the orthogonal function can be not only Fourier or Legendre series, but also can be any one of all orthogonal function systems. These kinds of biorthogonal function sets are used as scramble signals to construct biorthogonal scramble modulation (BOSM) wireless transmission systems. In a BOSM system, the transmitted signal has significant security performance. Several different BOSM and orthogonal systems are compared on aspects of BER performance and spectrum efficiency, simulation results show that the BOSM systems based on Chebyshev polynomial and Legendre polynomial are better than BOSM system based on Fourier series, also better than orthogonal MCM and OFDM systems. 展开更多
关键词 BIORTHOGONAL functions BIORTHOGONAL SCRAMBLE Modulation Generalized FOURIER Series MOBIUS inverse Wireless Transmission
下载PDF
感应测井的最小平方反滤波 被引量:1
11
作者 朱军 夏克文 《测井技术》 CAS CSCD 1993年第6期433-441,共9页
感应测井响应是地层非线性时变滤波的结果。获得地层真电导率的方法就是将感应测井响应进行非线性时变的反滤波处理。本文用最小平方法设计出了一种非线性的反滤波因子,并对模拟的感应测井响应曲线进行了处理。结果表明,与传统的处理方... 感应测井响应是地层非线性时变滤波的结果。获得地层真电导率的方法就是将感应测井响应进行非线性时变的反滤波处理。本文用最小平方法设计出了一种非线性的反滤波因子,并对模拟的感应测井响应曲线进行了处理。结果表明,与传统的处理方法(包括三因子反滤波和趋肤效应提升)相比,该方法可大大地改进感应测井的精度。 展开更多
关键词 感应测井 最小平方 反滤波 电测井
下载PDF
RKRLS及在混炼胶质量建模与预报中的应用研究 被引量:1
12
作者 解应春 王海清 李平 《浙江大学学报(工学版)》 EI CAS CSCD 北大核心 2004年第8期941-945,共5页
对递推最小二乘(RLS)进行了非线性的核(kernel)变换,并采用正则化技术改写了目标范函,提出了一种正则核变换递推最小二乘(regularizedkernel,RLS)算法.获得了RKRLS模型的系数和误差表达式,分析了算法的推广能力并证明了KeYnelRLS算法为... 对递推最小二乘(RLS)进行了非线性的核(kernel)变换,并采用正则化技术改写了目标范函,提出了一种正则核变换递推最小二乘(regularizedkernel,RLS)算法.获得了RKRLS模型的系数和误差表达式,分析了算法的推广能力并证明了KeYnelRLS算法为其特例,进而导出了RKRLS算法在限定、增长和缩减记忆三种不同模式下的递推公式均无需进行求逆计算.RKRLS算法具有三个特性:小样本、可控的推广能力和速度快,因而非常适合于工业应用场合.通过对橡胶混炼质量的门尼指标进行建模和预测分析表明,本算法具有较好的跟踪预测性能. 展开更多
关键词 递推最小二乘 核函数 正则化 混炼胶 时间序列分析
下载PDF
A Class of Inverse Boundary Value Problems for (λ,1) Bi-Analytic Functions
13
作者 LIN Juan 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2023年第3期185-191,共7页
In this paper,a class of inverse boundary value problems for(λ,1)bi-analytic functions is given.Using the method of Riemann boundary value problem for analytic functions,the conditions of solvability and the expressi... In this paper,a class of inverse boundary value problems for(λ,1)bi-analytic functions is given.Using the method of Riemann boundary value problem for analytic functions,the conditions of solvability and the expression of the solutions for the inverse problems are obtained. 展开更多
关键词 inverse problem Riemann boundary value problem k)bi-analytic functions canonical function
原文传递
Solving Cauchy Issues of Highly Nonlinear Elliptic Equations Using a Meshless Method
14
作者 Chih-Wen Chang 《Computers, Materials & Continua》 SCIE EI 2022年第8期3231-3245,共15页
In this paper,we address 3D inverse Cauchy issues of highly nonlinear elliptic equations in large cuboids by utilizing the new 3D homogenization functions of different orders to adapt all the specified boundary data.W... In this paper,we address 3D inverse Cauchy issues of highly nonlinear elliptic equations in large cuboids by utilizing the new 3D homogenization functions of different orders to adapt all the specified boundary data.We also add the average classification as an approximate solution to the nonlinear operator part,without requiring to cope with nonlinear equations to resolve the weighting coefficients because these constructions are owned many conditions about the true solution.The unknown boundary conditions and the result can be retrieved straightway by coping with a small-scale linear system when the outcome is described by a new 3D homogenization function,which is right to find the numerical solutions with the errors smaller than the level of noise being put on the over-specified Neumann conditions on the bottom of the cuboid.Besides,note that the new homogenization functions method(HFM)does not require dealing with the regularization and highly nonlinear equations.The robustness and accuracy of the HFM are verified by comparing the recovered results of several numerical experiments to the exact solutions in the entire region,even though a very large level of noise 50%is imposed on the over specified Neumann conditions.The numerical errors of our scheme are in the order of O(10^(−1))-O(10^(−4)). 展开更多
关键词 inverse cauchy problems homogenization functions method(HFM) 3D highly nonlinear elliptic equations 3D homogenization functions
下载PDF
单叶亚纯函数逆函数的一些极值问题
15
作者 黄新民 张玉宏 《广西大学学报(自然科学版)》 CAS CSCD 1990年第2期56-60,共5页
设∑′表示|Z|>1中单叶解析,在∞处有一个一阶极点的函数F(z)=z+sum from n=1 to ∞ b_n/z^n的全体。∑′中奇函数的子族记为∑′_(odd)而以∑′^(+1),∑′_(odd)^(-1)分别表示它们的逆函数子族。本文用变分法重新获得∑′_(odd)^(-1... 设∑′表示|Z|>1中单叶解析,在∞处有一个一阶极点的函数F(z)=z+sum from n=1 to ∞ b_n/z^n的全体。∑′中奇函数的子族记为∑′_(odd)而以∑′^(+1),∑′_(odd)^(-1)分别表示它们的逆函数子族。本文用变分法重新获得∑′_(odd)^(-1)中一个准确估计,讨论了∑′_(odd)^(-1)中这个估计与Spriger猜想的关系。在∑′^(-1)中还给出了一个新的准确的估计。 展开更多
关键词 单叶亚纯函数 逆函数 系数 极值
下载PDF
关于分段函数的教学
16
作者 彭奇林 赵士银 《河南教育学院学报(自然科学版)》 2001年第3期11-13,共3页
针对高等数学教学中的薄弱环节 ,考虑分段函数教学的有关问题 ,包括分段函数的定义 ,图像 ,单调性 ,奇偶性 ,反函数及复合函数等 ;提出了几个相关结论 ;
关键词 分段函数 定义 图像 单调性 反函数 复合函数
下载PDF
Wave Kernels with Bi-Inverse Square Potentials on Euclidean Plane
17
作者 MOUSTAPHA Mohamed Vall Ould 《Journal of Partial Differential Equations》 CSCD 2015年第1期9-22,共14页
The Cauchy problem for the wave equation with bi-inverse square potential on Euclidean plane is solved in terms of the two variables Appell F2 hypergeometric functions. Our principal tools are the Hankel transforms an... The Cauchy problem for the wave equation with bi-inverse square potential on Euclidean plane is solved in terms of the two variables Appell F2 hypergeometric functions. Our principal tools are the Hankel transforms and the special functions of mathematical physics. 展开更多
关键词 inverse square potential wave equation Hankel transform Bessl functions F2- Appell hypergeometric function.
原文传递
A Meshless Method for Retrieving Nonlinear Large External Forces on Euler-Bernoulli Beams
18
作者 Chih-Wen Chang 《Computers, Materials & Continua》 SCIE EI 2022年第10期433-451,共19页
We retrieve unknown nonlinear large space-time dependent forces burdened with the vibrating nonlinear Euler-Bernoulli beams under varied boundary data,comprising two-end fixed,cantilevered,clamped-hinged,and simply su... We retrieve unknown nonlinear large space-time dependent forces burdened with the vibrating nonlinear Euler-Bernoulli beams under varied boundary data,comprising two-end fixed,cantilevered,clamped-hinged,and simply supported conditions in this study.Even though some researchers used several schemes to overcome these forward problems of Euler-Bernoulli beams;however,an effective numerical algorithm to solve these inverse problems is still not available.We cope with the homogeneous boundary conditions,initial data,and final time datum for each type of nonlinear beam by employing a variety of boundary shape functions.The unknown nonlinear large external force can be recuperated via back-substitution of the solution into the nonlinear Euler-Bernoulli beam equation when we acquire the solution by utilizing the boundary shape function scheme and deal with a smallscale linear system to gratify an additional right-side boundary data.For the robustness and accuracy,we reveal that the current schemes are substantiated by comparing the recuperated numerical results of four instances to the exact forces,even though a large level of noise up to 50%is burdened with the overspecified conditions.The current method can be employed in the online real-time computation of unknown force functions in space-time for varied boundary supports of the vibrating nonlinear beam. 展开更多
关键词 inverse problems nonlinear Euler-Bernoulli beams ill-posed problems nonlinear space-time dependent force boundary shape functions
下载PDF
感应测井反褶积因子的优化设计
19
作者 罗岚 高嵩 +1 位作者 李少康 盛钢 《西安工业学院学报》 1999年第1期11-15,共5页
感应测井测得的是地层视电导率,获得地层真电导率的方法之一就是将感应测井响应进行反滤波处理.如果使用空间频域滤波的方法设计反滤波因子,由于感应测井响应函数存在盲频率,会产生严重的吉布斯效应.本文用Remez交换法设计反... 感应测井测得的是地层视电导率,获得地层真电导率的方法之一就是将感应测井响应进行反滤波处理.如果使用空间频域滤波的方法设计反滤波因子,由于感应测井响应函数存在盲频率,会产生严重的吉布斯效应.本文用Remez交换法设计反滤波因子,能够有效地减弱吉布斯效应,得到较理想的真电导率曲线. 展开更多
关键词 感应测井 优化设计 数据处理 反褶积因子
下载PDF
变增益的完全补偿原理
20
作者 鲁好忠 《青岛大学学报(工程技术版)》 CAS 1999年第4期70-71,共2页
对于过程控制系统设计时的非线性增益补偿问题,根据逆函数,提出了完全补偿原理。
关键词 非线性增益 完全补偿 自动控制系统
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部