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Strong Convergence and Its Rate of Modified Partitioning Estimation for Nonparametric Regression Function under Dependence Samples 被引量:5
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作者 凌能祥 《Northeastern Mathematical Journal》 CSCD 2004年第3期349-354,共6页
In this paper, we study the strong consistency and convergence rate for modified partitioning estimation of regression function under samples that are ψ-mixing with identically distribution.
关键词 partitioning esfimation strong convergence convergence rate nonpara-metric regression function Ψ-MIXING
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Generalised Error Functions from the Kerr Metric
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作者 唐文林 罗子人 刘润球 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第3期12-16,共5页
Motivated by the effort to understand the mathematical structure underlying the Teukolsky equations in a Kerr metric background, a homogeneous integral equation related to the prolate spheroidal function is studied. F... Motivated by the effort to understand the mathematical structure underlying the Teukolsky equations in a Kerr metric background, a homogeneous integral equation related to the prolate spheroidal function is studied. From the consideration of the Fredholm determinant of the integral equation, a family of generalized error function is defined, with which the Fredholm determinant of the sinc kernel is also evaluated. An analytic solution of a special ease of the fifth Painlev~ transcendent is then worked out explicitly. 展开更多
关键词 of IS exp in Generalised Error functions from the Kerr metric from
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Common Fixed Point Results for Quasi-contractions Involving Altering Distance Functions in Ordered Cone Metric Spaces 被引量:1
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作者 SONG Ji-ping WANG Mao-fa 《Chinese Quarterly Journal of Mathematics》 2018年第1期1-16,共16页
Some common fixed point results for mappings satisfying a quasi-contractive condition which involves altering distance functions are obtained in partially ordered complete cone metric spaces. A sufficient condition fo... Some common fixed point results for mappings satisfying a quasi-contractive condition which involves altering distance functions are obtained in partially ordered complete cone metric spaces. A sufficient condition for the uniqueness of common fixed point is proved. Also, an example is given to support our results. 展开更多
关键词 partially ordered cone metric space quasi-contraction common fixed point altering distance function
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AXISYMMETRIC BENDING OF TWO-DIRECTIONAL FUNCTIONALLY GRADED CIRCULAR AND ANNULAR PLATES 被引量:6
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作者 Guojun Nie Zheng Zhong 《Acta Mechanica Solida Sinica》 SCIE EI 2007年第4期289-295,共7页
Assuming the material properties varying with an exponential law both in the thick- ness and radial directions, axisymmetric bending of two-directional functionally graded circular and annular plates is studied using ... Assuming the material properties varying with an exponential law both in the thick- ness and radial directions, axisymmetric bending of two-directional functionally graded circular and annular plates is studied using the semi-analytical numerical method in this paper. The deflections and stresses of the plates are presented. Numerical results show the well accuracy and convergence of the method. Compared with the finite element method, the semi-analytical nu- merical method is with great advantage in the computational efficiency. Moreover, study on ax- isymmetric bending of two-directional functionally graded annular plate shows that such plates have better performance than those made of isotropic homogeneous materials or one-directional functionally graded materials. Two-directional functionally graded material is a potential alternative to the one-directional functionally graded material. And the integrated design of materials and structures can really be achieved in two-directional functionally graded materials. 展开更多
关键词 two-directional functionally graded materials circular and annular plates axisym-metric bending semi-analytical numerical method integrated design
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改进DDPG的磁浮控制研究
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作者 张振利 宋成林 +1 位作者 汪永壮 杨杰 《工程科学学报》 北大核心 2026年第2期422-435,共14页
针对部分传统磁浮控制算法依赖精确模型、适应性差的问题,提出一种基于强化学习的改进型深度确定性策略梯度(Improvement deep deterministic policy gradient, IDDPG)控制方法.首先,搭建电磁悬浮系统数学模型并分析其动态特性.其次,针... 针对部分传统磁浮控制算法依赖精确模型、适应性差的问题,提出一种基于强化学习的改进型深度确定性策略梯度(Improvement deep deterministic policy gradient, IDDPG)控制方法.首先,搭建电磁悬浮系统数学模型并分析其动态特性.其次,针对传统DDPG算法在电磁悬浮控制中的不足,设计一种分段式反比例奖励函数,以提升稳态精度和响应速度,并对DDPG控制流程进行分析及优化,以满足实际部署需求.最后,通过仿真与实验,对比分析电流环跟踪、奖励函数、训练步长以及模型变化对控制性能的影响.结果表明:采用分段式反比例奖励函数的IDDPG控制器在降低稳态误差和超调的同时,显著提升系统的响应速度,且优化后的控制流程适用于实际系统部署.此外,不同模型下使用相同参数稳态误差均低于5%,取得基本一致的控制效果,远优于滑模控制(Sliding mode control, SMC)的31%和比例–积分–微分控制(Proportional–Integral–Derivative control, PID)的12%,验证了IDDPG在不依赖精确模型情况下的良好适应性.同时,抗扰实验中,IDDPG相比PID超调减少51%,调节时间缩短49%,具有更强抗扰性. 展开更多
关键词 DDPG 奖励函数 控制指标 系统建模 磁浮系统 学习步长
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Spherical Symmetric Solitons of Interacting Spinor, Scalar and Gravitational Fields in General Relativity
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作者 Jonas Edou Alain Adomou Siaka Massou 《Journal of High Energy Physics, Gravitation and Cosmology》 2021年第1期52-65,共14页
The concept of soliton as regular localized stable solutions of nonlinear differential equations is being widely utilized in pure science for various aims. In present analysis, the soliton concept is used as a model i... The concept of soliton as regular localized stable solutions of nonlinear differential equations is being widely utilized in pure science for various aims. In present analysis, the soliton concept is used as a model in order to describe the configurations of elementary particles in general relativity. To this end, our study deals with the spherical symmetric solitons of interacting Spinor, Scalar and Gravitational Fields in General Relativity. Thus, exact spherical symmetric general solutions to the interaction of spinor, scalar and gravitational field equations have been obtained. The Einstein equations have been transformed into a Liouville equation type and solved. Let us emphasize that these solutions are regular with localized energy density and finite total energy. In addition, the total charge and spin are limited. Moreover, the obtained solutions are soliton-like solutions. These solutions can be used in order to describe the configurations of elementary particles. 展开更多
关键词 Liouville Type Equation Elementary Particles Einstein’s Equations metric functions
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Uniqueness of Common Fixed Points for a Family of Mappings with <i>Φ</i>-Contractive Condition in 2-Metric Spaces 被引量:9
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作者 Yong-Jie Piao 《Applied Mathematics》 2012年第1期73-77,共5页
In this paper, we will introduce a class of 5-dimensional functions Φ and prove that a family of self-mappings {Ti,j} iεN in 2-metric space have an unique common fixed point if 1) {Ti,j} iεN satisfies Φj-contracti... In this paper, we will introduce a class of 5-dimensional functions Φ and prove that a family of self-mappings {Ti,j} iεN in 2-metric space have an unique common fixed point if 1) {Ti,j} iεN satisfies Φj-contractive condition, where ΦjεΦ, for each jεN;2) Tm,μ n,v for all m,n,μ,vεN with μ ≠ v . Our main result generalizes and unifies many known unique common fixed point theorems in 2-metric spaces. 展开更多
关键词 2-metric Space 5-Dimensional functions Φ Φ-Contractive CONDITION CAUCHY Sequence Common Fixed Point
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Examining the distribution and dynamics of impervious surface in different function zones in Beijing 被引量:6
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作者 乔琨 朱文泉 +3 位作者 胡德勇 郝明 陈姗姗 曹诗颂 《Journal of Geographical Sciences》 SCIE CSCD 2018年第5期669-684,共16页
Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for t... Impervious surface(IS) is often recognized as the indicator of urban environmental changes. Numerous research efforts have been devoted to studying its spatio-temporal dynamics and ecological effects, especially for the IS in Beijing metropolitan region. However, most previous studies primarily considered the Beijing metropolitan region as a whole without considering the differences and heterogeneity among the function zones. In this study, the subpixel impervious surface results in Beijing within a time series(1991, 2001, 2005, 2011 and 2015) were extracted by means of the classification and regression tree(CART) model combined with change detection models. Then based on the method of standard deviation ellipse, Lorenz curve, contribution index(CI) and landscape metrics, the spatio-temporal dynamics and variations of IS(1991, 2001, 2011 and 2015) in different function zones and districts were analyzed. It is found that the total area of impervious surface in Beijing increased dramatically during the study period, increasing about 144.18%. The deflection angle of major axis of standard deviation ellipse decreased from 47.15° to 38.82°, indicating the major development axis in Beijing gradually moved from northeast-southwest to north-south. Moreover, the heterogeneity of impervious surface’s distribution among 16 districts weakened gradually, but the CI values and landscape metrics in four function zones differed greatly. The urban function extended zone(UFEZ), the main source of the growth of IS in Beijing, had the highest CI values. Its lowest CI value was 1.79 that is still much higher than the highest CI value in other function zones. The core function zone(CFZ), the traditional aggregation zone of impervious surface, had the highest contagion index(CONTAG) values, but it contributed less than UFEZ due to its small area. The CI value of the new urban developed zone(NUDZ) increased rapidly, and it increased from negative to positive and multiplied, becoming animportant contributor to the rise of urban impervious surface. However, the ecological conservation zone(ECZ) had a constant negative contribution all the time, and its CI value decreased gradually. Moreover, the landscape metrics and centroids of impervious surface in different density classes differed greatly. The high-density impervious surface had a more compact configuration and a greater impact on the eco-environment. 展开更多
关键词 impervious surface landscape metrics classification and regression tree(CART) function zones Lorenz curve contribution index
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Block-Based Steganographic Algorithm Using Modulus Function and Pixel-Value Differencing 被引量:1
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作者 Ahlam K. Al-Dhamari Khalid A. Darabkh 《Journal of Software Engineering and Applications》 2017年第1期56-77,共22页
The main purpose in developing the steganographic algorithms lies in achieving most of the steganographic objectives which comprise the embedding capacity, imperceptibility, security, robustness and complexity. In thi... The main purpose in developing the steganographic algorithms lies in achieving most of the steganographic objectives which comprise the embedding capacity, imperceptibility, security, robustness and complexity. In this paper, we propose a high quality steganographic algorithm using new block structure which makes a good use of both modulus function and pixel-value differencing, namely, MF-PVD. We have made many experiments with various test images from several galleries, such as USC-SIPI and UWATERLOO-LINK. The performance of our proposed algorithm is verified using three different performance metrics which include peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), and embedding capacity (EC). Experimental results and comparisons with six pertinent state-of-art algorithms are given to prove the validation and efficiency of the proposed algorithm. 展开更多
关键词 Data Hiding STEGANOGRAPHY WATERMARKING Pixel-Value Differencing MODULUS function Performance metrics
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Dynamic fan-in and fan-out metrics for program comprehension
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作者 王玉英 李青山 +1 位作者 陈平 任春德 《Journal of Shanghai University(English Edition)》 CAS 2007年第5期474-479,共6页
In this paper, an approach to use run-time information to discover knowledge about software systems thus facilitating program comprehension is presented. Some dynamic metrics based on traces of the subject system exec... In this paper, an approach to use run-time information to discover knowledge about software systems thus facilitating program comprehension is presented. Some dynamic metrics based on traces of the subject system execution are proposed. A method of getting these dynamic metrics is introduced, in which instrumentation is implemented by using reflective mechanism based on an open compiler. The system run-time information is captured during the instrumented system running and is then analyzed to get these dynamic metrics. A case study is given to illustrate the use of these dynamic metrics, i.e., identifying critical components of the subject system. These critical components should be focus on user attentions in order to understand the subject system well. 展开更多
关键词 program comprehension dynamic metrics critical components functionality
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A Family of Non-Self Maps Satisfying <i>Φ</i><sub>i</sub>-Contractive Condition and Having Unique Common Fixed Point in Metrically Convex Spaces 被引量:1
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作者 Yongjie Piao Dongzhe Piao 《Advances in Pure Mathematics》 2012年第4期280-284,共5页
Class of 5-dimensional functions Φ was introduced and a convergent sequence determined by non-self mappings satisfying certain Φi-contractive condition was constructed, and then that the limit of the sequence is the... Class of 5-dimensional functions Φ was introduced and a convergent sequence determined by non-self mappings satisfying certain Φi-contractive condition was constructed, and then that the limit of the sequence is the unique com-mon fixed point of the mappings was proved. Finally, several more general forms were given. Our main results gener-alize and unify many same type fixed point theorems in references. 展开更多
关键词 metrically Convex Space 5-Dimensional functions Φ Φi-Contractive CONDITION Common Fixed Point Complete
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A Note on the Selection Expectation and Support Function
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作者 Rigao He 《Advances in Pure Mathematics》 2015年第10期583-586,共4页
In this paper, we prove the relationship between selection expectation and support function by a new method.
关键词 Support function HAUSDORFF metric RANDOM Set SELECTION EXPECTATION
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A Remark on the Uniform Convergence of Some Sequences of Functions
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作者 Guy Degla 《Advances in Pure Mathematics》 2015年第9期527-533,共7页
We stress a basic criterion that shows in a simple way how a sequence of real-valued functions can converge uniformly when it is more or less evident that the sequence converges uniformly away from a finite number of ... We stress a basic criterion that shows in a simple way how a sequence of real-valued functions can converge uniformly when it is more or less evident that the sequence converges uniformly away from a finite number of points of the closure of its domain. For functions of a real variable, unlike in most classical textbooks our criterion avoids the search of extrema (by differential calculus) of their general term. 展开更多
关键词 Sequence of functionS UNIFORM CONVERGENCE metric BOUNDEDNESS
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COMMON FIXED POINT OF GENERALIZED WEAKLY CONTRACTIVE MAPS IN PARTIAL METRIC SPACES 被引量:5
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作者 Vesna COJBAIC RAJIC Stojan RADENOVIC Sunny CHAUHAN 《Acta Mathematica Scientia》 SCIE CSCD 2014年第4期1345-1356,共12页
In this paper, using the context of complete partial metric spaces, some common fixed point results of maps that satisfy the generalized (ψ, Ф)-weak contractive conditions are obtained. Our results generalize, ext... In this paper, using the context of complete partial metric spaces, some common fixed point results of maps that satisfy the generalized (ψ, Ф)-weak contractive conditions are obtained. Our results generalize, extend, unify, enrich and complement many existing results in the literature. Example are given showing the validaty of our results. 展开更多
关键词 Common fixed point lower semi-continuous function weak (ψ Ф)-contraction partial metric space
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Common Fixed Points for Two Mappings with Implicit-linear Contractions on Partially Ordered 2-metric Spaces
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作者 PIAO YONG-JIE 《Communications in Mathematical Research》 CSCD 2019年第3期225-234,共10页
In this paper, we introduce a new class U of 3-dimensional real functions, use U and a 2-dimensional real function ? to construct a new implicit-linear contractive condition and obtain some existence theorems of commo... In this paper, we introduce a new class U of 3-dimensional real functions, use U and a 2-dimensional real function ? to construct a new implicit-linear contractive condition and obtain some existence theorems of common fixed points for two mappings on partially ordered 2-metric spaces and give a sufficient condition under which there exists a unique common fixed point. The obtained results goodly generalize and improve the corresponding conclusions in references. 展开更多
关键词 2-metric space class U of functions implicit-linear CONTRACTION common fixed point
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Characterizations of Semi-Metric Spaces
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作者 Erguang YANG 《Journal of Mathematical Research with Applications》 CSCD 2015年第3期350-354,共5页
We use the notions of weak base g-functions and pair networks to give some new characterizations of semi-metric spaces.
关键词 semi-metric spaces weak base g-functions pair networks co-cushioned families
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PSEUDOHYPERBOLIC METRIC AND UNIFORMLY DISCRETE SEQUENCES IN THE REAL UNIT BALL
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作者 任广斌 Uwe KHLER 《Acta Mathematica Scientia》 SCIE CSCD 2014年第3期629-638,共10页
We present an overview of the properties of the pseudohyperbolic metric in several real dimensions and study uniformly discrete sequences for the real unit ball in R^n.
关键词 Uniformly discrete sequences harmonic functions Bergman spaces pseudohy-perbolic metric
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Fixed Point Theorems of the Iterated Function Systems
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作者 Ji You-qing Liu Zhi Ri Song-il 《Communications in Mathematical Research》 CSCD 2016年第2期142-150,共9页
In this paper, we present some fixed point theorems of iterated function systems consisting of α-ψ-contractive type mappings in Fractal space constituted by the compact subset of metric space and iterated function s... In this paper, we present some fixed point theorems of iterated function systems consisting of α-ψ-contractive type mappings in Fractal space constituted by the compact subset of metric space and iterated function systems consisting of Banach contractive mappings in Fractal space constituted by the compact subset of generalized metric space, which is Mso extensively applied in topological dynamic system. 展开更多
关键词 fixed point α-ψ-contractive mapping iterated function system gener-alized metric space
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二维单项式多面体与复欧氏空间的公共子流形
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作者 程晓亮 桂琳 马会波 《贵州师范大学学报(自然科学版)》 北大核心 2025年第5期92-96,共5页
K hler流形间的全纯等距嵌入问题是多复变领域的热点问题之一。单项式多面体是Hartogs三角形的非平凡推广,研究其与复欧氏空间是否具有公共子流形是有意义的。借助Nash函数的性质及二维单项式多面体的Bergman核函数,得到具有Bergman度... K hler流形间的全纯等距嵌入问题是多复变领域的热点问题之一。单项式多面体是Hartogs三角形的非平凡推广,研究其与复欧氏空间是否具有公共子流形是有意义的。借助Nash函数的性质及二维单项式多面体的Bergman核函数,得到具有Bergman度量的二维单项式多面体与具有平坦度量的复欧氏空间不存在公共的K hler子流形,即二维单项式多面体与复欧氏空间是不相关的。 展开更多
关键词 单项式多面体 全纯等距嵌入 BERGMAN度量 Nash函数
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On Geodesic E-quasiconvex Functions and Geodesic E-epigraphs
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作者 LIN Qing-ying HUANG Long-guang 《Chinese Quarterly Journal of Mathematics》 2015年第2期184-189,共6页
The definition of geodesic E-quasiconvex functions is established in a geodesic metric space. Meanwhile, the relations of geodesic E-quasiconvex functions, geodesic Econvex functions and geodesic E-almostconvex functi... The definition of geodesic E-quasiconvex functions is established in a geodesic metric space. Meanwhile, the relations of geodesic E-quasiconvex functions, geodesic Econvex functions and geodesic E-almostconvex functions are studied. Furthermore, the notion of E-epigraphs is generalized to geodesic E-epigraphs and a characterization of geodesic E-quasiconvex functions in terms of its geodesic E-epigraphs is considered. 展开更多
关键词 geodesic metric space geodesic E-quasiconvex functions geodesic E-almostconvex functions geodesic E-convex functions geodesic E-epigraphs
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