期刊文献+
共找到574篇文章
< 1 2 29 >
每页显示 20 50 100
Adaptive Learning Rate Optimization BP Algorithm with Logarithmic Objective Function
1
作者 李春雨 盛昭瀚 《Journal of Southeast University(English Edition)》 EI CAS 1997年第1期47-51,共5页
This paper presents an improved BP algorithm. The approach can reduce the amount of computation by using the logarithmic objective function. The learning rate μ(k) per iteration is determined by dynamic o... This paper presents an improved BP algorithm. The approach can reduce the amount of computation by using the logarithmic objective function. The learning rate μ(k) per iteration is determined by dynamic optimization method to accelerate the convergence rate. Since the determination of the learning rate in the proposed BP algorithm only uses the obtained first order derivatives in standard BP algorithm(SBP), the scale of computational and storage burden is like that of SBP algorithm,and the convergence rate is remarkably accelerated. Computer simulations demonstrate the effectiveness of the proposed algorithm 展开更多
关键词 BP ALGORITHM ADAPTIVE LEARNING RATE optimization fault diagnosis logarithmic objective function
在线阅读 下载PDF
Logarithmic Sine and Cosine Transforms and Their Applications to Boundary-Value Problems Connected with Sectionally-Harmonic Functions
2
作者 Mithat Idemen 《Applied Mathematics》 2013年第2期378-386,共9页
Let stand for the polar coordinates in R2, ?be a given constant while satisfies the Laplace equation in the wedge-shaped domain or . Here αj(j = 1,2,...,n + 1) denote certain angles such that αj αj(j = 1,2,...,n + ... Let stand for the polar coordinates in R2, ?be a given constant while satisfies the Laplace equation in the wedge-shaped domain or . Here αj(j = 1,2,...,n + 1) denote certain angles such that αj αj(j = 1,2,...,n + 1). It is known that if r = a satisfies homogeneous boundary conditions on all boundary lines ?in addition to non-homogeneous ones on the circular boundary , then an explicit expression of in terms of eigen-functions can be found through the classical method of separation of variables. But when the boundary?condition given on the circular boundary r = a is homogeneous, it is not possible to define a discrete set of eigen-functions. In this paper one shows that if the homogeneous condition in question is of the Dirichlet (or Neumann) type, then the logarithmic sine transform (or logarithmic cosine transform) defined by (or ) may be effective in solving the problem. The inverses of these transformations are expressed through the same kernels on or . Some properties of these transforms are also given in four theorems. An illustrative example, connected with the heat transfer in a two-part wedge domain, shows their effectiveness in getting exact solution. In the example in question the lateral boundaries are assumed to be non-conducting, which are expressed through Neumann type boundary conditions. The application of the method gives also the necessary condition for the solvability of the problem (the already known existence condition!). This kind of problems arise in various domain of applications such as electrostatics, magneto-statics, hydrostatics, heat transfer, mass transfer, acoustics, elasticity, etc. 展开更多
关键词 INTEGRAL Transforms Harmonic functions WEDGE PROBLEMS Boundary-Value PROBLEMS logarithmic SINE TRANSFORM logarithmic COSINE TRANSFORM
在线阅读 下载PDF
Constructing Hash Function Based on Coupled Network Generated by Logarithmic Map
3
作者 SONG Yu-rong JIANG Guo-ping 《南京邮电大学学报(自然科学版)》 2010年第1期6-10,共5页
In this paper,based on coupled network generated by chaotic logarithmic map,a novel algorithm for constructing hash functions is proposed,which can transform messages and can establish a mapping from the transformed m... In this paper,based on coupled network generated by chaotic logarithmic map,a novel algorithm for constructing hash functions is proposed,which can transform messages and can establish a mapping from the transformed messages to the coupled matrix of the network.The network model is carefully designed to ensure the network dynamics to be chaotic.Through the chaotic iterations of the network,quantization and exclusive-or (XOR) operations,the algorithm can construct hash value with arbitrary length.It is shown by simulations that the algorithm is extremely sensitive to the initial values and the coupled matrix of the network,and has excellent performance in one-way,confusion and diffusion,and collision resistance. 展开更多
关键词 计算机网络 应用程序 网络安全 网络协议
在线阅读 下载PDF
Existence of a Sigh-Changing Solution Result for Logarithmic Schrödinger Equations with Weight Function
4
作者 Jingxing Huang Junhui Xie 《Journal of Applied Mathematics and Physics》 2024年第7期2665-2681,共17页
This paper is devoted to studying the existence of solutions for the following logarithmic Schrödinger problem: −div(a(x)∇u)+V(x)u=ulogu2+k(x)| u |q1−2u+h(x)| u |q2−2u,  x∈ℝN.(1)We first prove that the correspon... This paper is devoted to studying the existence of solutions for the following logarithmic Schrödinger problem: −div(a(x)∇u)+V(x)u=ulogu2+k(x)| u |q1−2u+h(x)| u |q2−2u,  x∈ℝN.(1)We first prove that the corresponding functional I belongs to C1(HV1(ℝN),ℝ). Furthermore, by using the variational method, we prove the existence of a sigh-changing solution to problem (1). 展开更多
关键词 logarithmic Schrödinger Equations Weight function Constrained Minimization Method Symmetric Mountain Pass Theorem
在线阅读 下载PDF
混合Pareto-logarithmic分布
5
作者 田兵 《常熟理工学院学报》 2021年第2期115-119,共5页
基于元件的寿命服从双参数的混合Pareto分布,而元件的个数服从Logarithmic分布.本文提出了一种新的寿命分布:混合Pareto-logarithmic分布(MPL分布),研究了MPL分布的各种性质,同时给出了其参数的极大似然估计的渐近协方差阵和近似置信区间.
关键词 PARETO分布 logarithmic分布 失效率函数 生存函数 极大似然估计
在线阅读 下载PDF
凸体的最小Logarithmic函数
6
作者 夏落燕 曾春娜 《西南师范大学学报(自然科学版)》 CAS 北大核心 2017年第6期28-31,共4页
为了解决Logarithmic Minkowski问题,已对球面上的任意有限偶Borel测度引入了Logarithmic函数.考虑单位球面上旋转不变概率测度的Logarithmic函数,并考虑它的最小值问题.
关键词 logarithmic函数 凸体 最小平均宽度
在线阅读 下载PDF
REGULARITY OF POISSON EQUATION IN SOME LOGARITHMIC SPACE
7
作者 Jia Huilian Li Dongsheng Wang Lihe 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2007年第1期29-36,共8页
In this note, the regularity of Poisson equation -△u = f with f lying in logarithmic function space L^P(LogL)^a(Ω)(1 〈 p 〈 ∞, a ∈ R) is studied. The result of the note generalizes the W^2,p estimate of Poi... In this note, the regularity of Poisson equation -△u = f with f lying in logarithmic function space L^P(LogL)^a(Ω)(1 〈 p 〈 ∞, a ∈ R) is studied. The result of the note generalizes the W^2,p estimate of Poisson equation in L^P(Ω). 展开更多
关键词 maximal function logarithmic function space distribution function.
在线阅读 下载PDF
Refinement of an Inequality for the Generalized Logarithmic Mean
8
作者 SHI Huan-nan WU Shan-he 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第4期594-599,共6页
In this article, we show that the generalized logarithmic mean is strictly Schurconvex function for p 〉 2 and strictly Schur-concave function for p 〈 2 on R_+^2. And then we give a refinement of an inequality for t... In this article, we show that the generalized logarithmic mean is strictly Schurconvex function for p 〉 2 and strictly Schur-concave function for p 〈 2 on R_+^2. And then we give a refinement of an inequality for the generalized logarithmic mean inequality using a simple majoricotion relation of the vector. 展开更多
关键词 INEQUALITY REFINEMENT generalized logarithmic mean strictly Schur-convex function strictly Schur-concave function
在线阅读 下载PDF
Logarithm of a Function, a Well-Posed Inverse Problem
9
作者 Silvia Reyes Mora Víctor A. Cruz Barriguete Denisse Guzmán Aguilar 《American Journal of Computational Mathematics》 2014年第1期1-5,共5页
It poses the inverse problem that consists in finding the logarithm of a function. It shows that when the function is holomorphic in a simply connected domain , the solution at the inverse problem exists and is unique... It poses the inverse problem that consists in finding the logarithm of a function. It shows that when the function is holomorphic in a simply connected domain , the solution at the inverse problem exists and is unique if a branch of the logarithm is fixed. In addition, it’s demonstrated that when the function is continuous in a domain , where is Hausdorff space and connected by paths. The solution of the problem exists and is unique if a branch of the logarithm is fixed and is stable;for what in this case, the inverse problem turns out to be well-posed. 展开更多
关键词 logarithm function INVERSE PROBLEM STABILITY
在线阅读 下载PDF
Local Rate of Convergence in the Functional Limit Theorem for Increments of a Fractional Brownian Motion 被引量:1
10
作者 LIU Yonghong DING Ding ZHOU Xia 《数学进展》 北大核心 2025年第1期197-211,共15页
In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):104... In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192]. 展开更多
关键词 fractional Brownian motion INCREMENT local functional law of the iterated logarithm large deviation small deviation
原文传递
A LAW OF THE ITERATED LOGARITHM FOR NEAREST NEIGHBOR ESTIMATION OF MULTIVARIATE DENSITY FUNCTION
11
作者 洪圣岩 陈规景 +1 位作者 孔繁超 高集体 《Acta Mathematica Scientia》 SCIE CSCD 1992年第4期472-478,共7页
Let X be a d-dimensional random vector with unknown density function f(z) = f (z1, ..., z(d)), and let f(n) be teh nearest neighbor estimator of f proposed by Loftsgaarden and Quesenberry (1965). In this paper, we est... Let X be a d-dimensional random vector with unknown density function f(z) = f (z1, ..., z(d)), and let f(n) be teh nearest neighbor estimator of f proposed by Loftsgaarden and Quesenberry (1965). In this paper, we established the law of the iterated logarithm of f(n) for general case of d greater-than-or-equal-to 1, which gives the exact pointwise strong convergence rate of f(n). 展开更多
关键词 A LAW OF THE ITERATED logarithm FOR NEAREST NEIGHBOR ESTIMATION OF MULTIVARIATE DENSITY function exp
在线阅读 下载PDF
A New Function for Modelling Diameter Frequency Distribution in the Tropical Rain Forest of Xishuangbanna,Southwest of China 被引量:6
12
作者 LuYuanchang LeiXiangdong JiangLei 《Forestry Studies in China》 CAS 2003年第2期1-6,共6页
Permanent plots in the montane tropical rain forests in Xishuangbanna, southwest China, were established, and different empirical models, based on observation data of these plots in 1992, were built to model diameter ... Permanent plots in the montane tropical rain forests in Xishuangbanna, southwest China, were established, and different empirical models, based on observation data of these plots in 1992, were built to model diameter frequency distributions. The focus of this study is on predicting accuracy of stem number in the larger diameter classes, which is much more important than that of the smaller trees, from the view of forest management, and must be adequately considered in the modelling and estimate. There exist 3 traditional ways of modelling the diameter frequency distribution: the negative exponential function model, limiting line function model, and Weibull distribution model. In this study, a new model, named as the logarithmic J-shape function, together with the others, was experimented and was found as a more suitable model for modelling works in the tropical forests. 展开更多
关键词 tropical forests diameter distribution modelling logarithmic j-shape function
在线阅读 下载PDF
Solutions for Series of Exponential Equations in Terms of Lambert-W Function and Fundamental Constants 被引量:1
13
作者 S. Gnanarajan 《Journal of Applied Mathematics and Physics》 2018年第4期725-736,共12页
Series of exponential equations in the form of were solved graphically, numerically and analytically. The analytical solution was derived in terms of Lambert-W function. A general numerical solution for any y is found... Series of exponential equations in the form of were solved graphically, numerically and analytically. The analytical solution was derived in terms of Lambert-W function. A general numerical solution for any y is found in terms of n or in base y. A solution is close to the fine structure constant. The equation which provided the solution as the fine structure constant was derived in terms of the fundamental constants. 展开更多
关键词 EXPONENTIAL EQUATION Lambert-W function Fine Structure Constant logarithmic EQUATION Numerical Analysis FUNDAMENTAL CONSTANTS
在线阅读 下载PDF
COMPLETE MONOTONICITY FOR A NEW RATIO OF FINITELY MANY GAMMA FUNCTIONS
14
作者 Feng QI 《Acta Mathematica Scientia》 SCIE CSCD 2022年第2期511-520,共10页
In this paper,by deriving an inequality involving the generating function of the Bernoulli numbers,the author introduces a new ratio of finitely many gamma functions,finds complete monotonicity of the second logarithm... In this paper,by deriving an inequality involving the generating function of the Bernoulli numbers,the author introduces a new ratio of finitely many gamma functions,finds complete monotonicity of the second logarithmic derivative of the ratio,and simply reviews the complete monotonicity of several linear combinations of finitely many digamma or trigamma functions. 展开更多
关键词 Bernoulli number RATIO generating function complete monotonicity gamma function digamma function trigamma function logarithmic derivative linear combination INEQUALITY
在线阅读 下载PDF
Integral Inequalities of Hermite-Hadamard Type for <i>r</i>-Convex Functions
15
作者 Lingxiong Han Guofeng Liu 《Applied Mathematics》 2012年第12期1967-1971,共5页
The main aim of this present note is to establish three new Hermite-Hadamard type integral inequalities for r-convex functions. The three new Hermite-Hadamard type integral inequalities for r-convex functions improve ... The main aim of this present note is to establish three new Hermite-Hadamard type integral inequalities for r-convex functions. The three new Hermite-Hadamard type integral inequalities for r-convex functions improve the result of original one by H?lder’s integral inequality, Stolarsky mean and convexity of function. 展开更多
关键词 Hermite-Hadamard Integral INEQUALITY r-Convex function logarithmic Mean Stolarsky Mean
在线阅读 下载PDF
On a special type of Ma-Minda function
16
作者 S.Sivaprasad Kumar Shagun Banga 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第4期654-673,共20页
We introduce a primitive class of analytic functions, by specializing in many wellknown classes, classify Ma-Minda functions based on its conditions and their interesting geometrical aspects. Further, study a newly de... We introduce a primitive class of analytic functions, by specializing in many wellknown classes, classify Ma-Minda functions based on its conditions and their interesting geometrical aspects. Further, study a newly defined subclass of starlike functions involving a special type of Ma-Minda function introduced here for obtaining inclusion and radius results. We also establish some majorization, Bloch function norms, and other related problems for the same class. 展开更多
关键词 Ma-Minda function typically real function Hankel determinants sharp coefficient bounds radius problems logarithmic function
在线阅读 下载PDF
Complements to the Theory of Higher-Order Types of Asymptotic Variation for Differentiable Functions 被引量:1
17
作者 Antonio Granata 《Advances in Pure Mathematics》 2019年第5期434-479,共46页
The purpose of this paper is to add some complements to the general theory of higher-order types of asymptotic variation developed in two previous papers so as to complete our elementary (but not too much!) theory in ... The purpose of this paper is to add some complements to the general theory of higher-order types of asymptotic variation developed in two previous papers so as to complete our elementary (but not too much!) theory in view of applications to the theory of finite asymptotic expansions in the real domain, the asymptotic study of ordinary differential equations and the like. The main results concern: 1) a detailed study of the types of asymptotic variation of an infinite series so extending the results known for the sole power series;2) the type of asymptotic variation of a Wronskian completing the many already-published results on the asymptotic behaviors of Wronskians;3) a comparison between the two main standard approaches to the concept of “type of asymptotic variation”: via an asymptotic differential equation or an asymptotic functional equation;4) a discussion about the simple concept of logarithmic variation making explicit and completing the results which, in the literature, are hidden in a quite-complicated general theory. 展开更多
关键词 HIGHER-ORDER Regularly-Varying functionS HIGHER-ORDER Rapidly-Varying functionS Smoothly-Varying functionS Exponentially-Varying functionS logarithmically-Varying functionS ASYMPTOTIC Differential EQUATIONS As-ymptotic functional EQUATIONS ASYMPTOTIC VARIATION of Wronskians
在线阅读 下载PDF
A New Approximation to the Jacobian Logarithm Suitable for MAP Decoding in BICM-ID
18
作者 Slimane Benmahmoud Ali Djebbari 《Computer Technology and Application》 2013年第5期241-244,共4页
In this paper, a new method to approximate the compensation term in the Jacobian logarithm used by the MAP decoder is proposed. Using the proposed approximation, the complex functions In(.) and exp(.) in the Exact... In this paper, a new method to approximate the compensation term in the Jacobian logarithm used by the MAP decoder is proposed. Using the proposed approximation, the complex functions In(.) and exp(.) in the Exact-log-MAP algorithm can be estimated with high accuracy and lower computational complexity. The efficacy of the proposed approximation is investigated and demonstrated by applying it to iteratively decoded BICM (Bit Interleaved Coded Modulation). 展开更多
关键词 LOG-MAP Bahl-Cocke-Jelinek-Raviv (BCJR) algorithm max function Jacobian logarithm correction (compensation)term function BICM-ID (Bit Interleaved Coded Modulation with Iterative Decoding).
在线阅读 下载PDF
基于水活度法测定包衣种子含水量
19
作者 潘佳 刘亚洁 胡小文 《中国草地学报》 北大核心 2025年第8期142-148,共7页
种子含水量是种子质量评定的重要指标,其准确、快速地测定对种子质量定级尤为重要。为提高种子质量,种子包衣技术在种子生产和贸易中已较为常见。因外围包衣材料的影响,传统的高(低)恒温烘干法无法准确测定种子含水量,往往严重低估包衣... 种子含水量是种子质量评定的重要指标,其准确、快速地测定对种子质量定级尤为重要。为提高种子质量,种子包衣技术在种子生产和贸易中已较为常见。因外围包衣材料的影响,传统的高(低)恒温烘干法无法准确测定种子含水量,往往严重低估包衣种子的实际含水量。鉴于此,本研究以紫花苜蓿、披碱草、多年生黑麦草、鸭茅等4个物种的包衣种子为试验材料,分析包衣种子水活度和裸种子含水量之间的关系,构建基于水活度的包衣种子含水量预测模型。结果表明紫花苜蓿、披碱草、多年生黑麦草、鸭茅4个物种预测模型的拟合优度分别为0.9003、0.9124、0.9076、0.9323,水分预测相对误差分别为2.87%、4.08%、3.07%、4.14%,表明种子水活度可用于包衣种子含水量的无损快速测定。 展开更多
关键词 数学模型 水活度 指数函数 裸种子 决定系数 拟合优度
在线阅读 下载PDF
面向向量部件的指数和对数函数优化方法
20
作者 沈洁 龙标 +2 位作者 黄春 唐滔 彭林 《计算机工程与科学》 北大核心 2025年第1期18-26,共9页
指数和对数函数是浮点计算中重要的超越函数,在不同应用领域使用广泛。现代处理器向量寄存器宽度呈现逐代增加的趋势,为了进一步提高上层应用对向量部件的利用率,研究向量指数和对数函数优化方法具有重要的科学价值和现实意义。针对现... 指数和对数函数是浮点计算中重要的超越函数,在不同应用领域使用广泛。现代处理器向量寄存器宽度呈现逐代增加的趋势,为了进一步提高上层应用对向量部件的利用率,研究向量指数和对数函数优化方法具有重要的科学价值和现实意义。针对现有向量函数实现的性能瓶颈,设计和实现了面向向量部件的指数和对数函数优化方法,包括基于硬件加速指令的向量查表优化、分支优化和精度性能取舍优化。模拟器上的实验表明,优化实现的向量指数和对数函数均达到业界高精度标准,函数性能优于当前最佳开源实现,加速比达1.44以上。真实应用测试进一步表明,应用程序在优化的向量函数支持下可以实现高效向量化,相比原始标量实现平均性能提升达2.53倍。 展开更多
关键词 指数函数 对数函数 向量化 查表优化 硬件加速指令
在线阅读 下载PDF
上一页 1 2 29 下一页 到第
使用帮助 返回顶部