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LIMITING DIRECTIONS OF JULIA SETS OF ENTIRE SOLUTIONS TO COMPLEX DIFFERENTIAL EQUATIONS 被引量:2
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作者 王珺 陈宗煊 《Acta Mathematica Scientia》 SCIE CSCD 2017年第1期97-107,共11页
In this paper,we mainly investigate the dynamical properties of entire solutions of complex differential equations.With some conditions on coefficients,we prove that the set of common limiting directions of Julia sets... In this paper,we mainly investigate the dynamical properties of entire solutions of complex differential equations.With some conditions on coefficients,we prove that the set of common limiting directions of Julia sets of solutions,their derivatives and their primitives must have a definite range of measure. 展开更多
关键词 limiting direction Julia set entire function linear differential equation defi-ciency
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A NOTE ON THE JULIA SETS OF ENTIRE SOLUTIONS TO DELAY DIFFERENTIAL EQUATIONS 被引量:2
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作者 李叶舟 孙合庆 《Acta Mathematica Scientia》 SCIE CSCD 2023年第1期143-155,共13页
Let f be an entire solution of the Tumura-Clunie type non-linear delay differential equation.We mainly investigate the dynamical properties of Julia sets of f,and the lower bound estimates of the measure of related li... Let f be an entire solution of the Tumura-Clunie type non-linear delay differential equation.We mainly investigate the dynamical properties of Julia sets of f,and the lower bound estimates of the measure of related limiting directions is verified. 展开更多
关键词 delay differential equation dynamical properties Julia sets limiting directions
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Function S-Rough sets and its applications 被引量:25
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作者 Cui Yuquan Shi Kaiquan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第2期331-338,共8页
Based on S-rough sets(singular rough sets), this paper presents function S-rough sets (function singular rough sets)and its mathematical structures and features. Function S-rough sets has two forms: function one ... Based on S-rough sets(singular rough sets), this paper presents function S-rough sets (function singular rough sets)and its mathematical structures and features. Function S-rough sets has two forms: function one direction S-rough sets (function one direction singular rough sets) and function two direction S-rough sets (function two direction singular rough sets). This paper advances the relationship theorem of function S-rough sets and S-rough sets. Function S-rough sets is the general form of S-rough sets, and S-rough sets is the special ease of function S-rough sets. In this paper, applications of function S-rough sets in rough law mining-discovery of system are given. Function S-rough sets is a new research direction of rough sets and rough system. 展开更多
关键词 function s-rough sets structure of function s-rough sets relationship theorem rough law mining-discovery applications.
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Function S-rough sets and mining-discovery of rough law in systems 被引量:25
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作者 Shi Kaiquan Xia Jiarong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2006年第4期919-926,共8页
Function S-rough sets (function singular rough sets) is defined on a -function equivalence class [u]. Function S-rough sets is the extension form of S-rough sets. By using the function S-rough sets, this paper gives... Function S-rough sets (function singular rough sets) is defined on a -function equivalence class [u]. Function S-rough sets is the extension form of S-rough sets. By using the function S-rough sets, this paper gives rough law generation model of a-function equivalence class, discussion on law mining and law discovery in systems, and application of law mining and law discovery in communication system. Function S-rough sets is a new theory and method in law mining research. 展开更多
关键词 function s-rough sets structure of function s-rough sets relationship theorem rough law mining-discovery applications.
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S-rough sets and the discovery of F-hiding knowledge 被引量:2
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作者 Hao Xiumei Fu Haiyan Shi Kaiquan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第6期1171-1177,共7页
Singular rough sets (S-rough sets) have three classes of forms: one-directional S-rough sets, dual of onedirectional S-rough sets, and two-directional S-rough sets. Dynamic, hereditary, mnemonic, and hiding propert... Singular rough sets (S-rough sets) have three classes of forms: one-directional S-rough sets, dual of onedirectional S-rough sets, and two-directional S-rough sets. Dynamic, hereditary, mnemonic, and hiding properties are the basic characteristics of S-rough sets. By using the S-rough sets, the concepts of f-hiding knowledge, F-hiding knowledge, hiding degree, and hiding dependence degree are given. Then, both the hiding theorem and the hiding dependence theorem of hiding knowledge are proposed. Finally, an application of hiding knowledge is discussed. 展开更多
关键词 one-direction s-rough sets f-hiding knowledge hiding degree hiding dependence degree hiding theorem hiding dependence theorem application
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Function S-rough Sets and Their Law Characteristic 被引量:1
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作者 李东亚 史开泉 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第2期225-231,共7页
Function S-rough sets(Function Singular rough sets) are defined by R-function equivalence class which has dynamic characteristic, and a function is s law, function S-rough sets have law characteristic. Function S-roug... Function S-rough sets(Function Singular rough sets) are defined by R-function equivalence class which has dynamic characteristic, and a function is s law, function S-rough sets have law characteristic. Function S-rough sets has these forms: function one direction S-rough sets, function two direction S-rough sets and dual of function one direction S-rough sets. This paper presents the law characteristic of function one direction S-rough sets and puts forward the theorems of law-chain-attribute and law-belt. Function S-rough sets is s new research direction of the rough sets theory. 展开更多
关键词 function one direction s-rough sets LAW the theorem of law-chain-attribute the theorem of law-belt
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On Limiting Directions of Julia Sets of Entire Solutions of Complex Differential Equations
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作者 XIA Xin ZHANG Ying HUANG Zhigang 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2024年第4期357-364,共8页
Assume that f is a transcendental entire function.The ray arg z=θ∈[0,2π]is said to be a limiting direction of the Julia set J(f)of f if there exists an unbounded sequence{z_(n)}■J(f)such that lim rn→∞ arg z_(n)=... Assume that f is a transcendental entire function.The ray arg z=θ∈[0,2π]is said to be a limiting direction of the Julia set J(f)of f if there exists an unbounded sequence{z_(n)}■J(f)such that lim rn→∞ arg z_(n)=θ.In this paper,we mainly investigate the dynamical properties of Julia sets of entire solutions of the complex differential equations F(z)f^(n)(z)+P(z,f)=0,and f^(n)+A(z)P(z,f)=h(z),where P(z,f)is a differential polynomial in f and its derivatives,F(z),A(z)and h(z)are entire functions.We demonstrate the existence of close relationships Petrenko's deviations of the coefficients and the measures of limiting directions of entire solutions of the above two equations. 展开更多
关键词 Julia set limiting direction entire function Petrenko's deviation
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THE REGULARITY OF RANDOM GRAPH DIRECTED SELF-SIMILAR SETS 被引量:2
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作者 ZhangXiaoqun LiuYanyan 《Acta Mathematica Scientia》 SCIE CSCD 2004年第3期485-492,共8页
A set in Rd is called regular if its Hausdorff dimension coincides with its upper box counting dimension. It is proved that a random graph-directed self-similar set is regular a.e..
关键词 Random graph-directed self-similar set Hausdorff dimension box-counting dimension REGULAR
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Function S-rough sets and two law forecast
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作者 Fu Haiyan Shi Kaiquan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第2期332-338,共7页
Function S-rough sets has the properties of dynamics, heredity, and memory. Function S-rough sets is penetrated and crossed with the issue of economic law forecast, then a new forecast model based on function S-rough ... Function S-rough sets has the properties of dynamics, heredity, and memory. Function S-rough sets is penetrated and crossed with the issue of economic law forecast, then a new forecast model based on function S-rough sets namely the two law forecast model is proposed, which includes upper law forecast model and lower law forecast model; and its' implement algorithm is given. Finally, the validity of the model is demonstrated by the forecast for region economic development of Hainan Province. 展开更多
关键词 function s-rough sets two law forecast dynamic economic system
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Designing a Protection Scheme in Micro-Grid Systems with DG Using Central Protection Unite and Multiple Setting Group Protection Relays
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作者 Mostafa I. Saleh Gaber El-Saady +1 位作者 Ali M. Yousef El-Noby A. Ibrahim 《Journal of Power and Energy Engineering》 2024年第9期37-49,共13页
Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this... Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains. 展开更多
关键词 directional Overcurrent Relay Protection Coordination Distributed Generators Central Protection Unite Multiple setting Group Protection Relay
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Optimality for Henig Proper Efficiency in Vector Optimization Involving Dini Set-Valued Directional Derivatives
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作者 Guolin Yu Huaipeng Bai 《Applied Mathematics》 2011年第7期922-925,共4页
This note studies the optimality conditions of vector optimization problems involving generalized convexity in locally convex spaces. Based upon the concept of Dini set-valued directional derivatives, the necessary an... This note studies the optimality conditions of vector optimization problems involving generalized convexity in locally convex spaces. Based upon the concept of Dini set-valued directional derivatives, the necessary and sufficient optimality conditions are established for Henig proper and strong minimal solutions respectively in generalized preinvex vector optimization problems. 展开更多
关键词 VECTOR Optimization Dini set-VALUED directional DERIVATIVE Generalized Preinvex Function Henig PROPER Efficiency
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基于Vague Sets-topsis理论的爆破方案优选 被引量:2
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作者 李小贝 蒙云琪 +1 位作者 吴剑锋 吝学飞 《爆破》 CSCD 北大核心 2018年第2期94-100,共7页
为了解决复杂框架结构楼房爆破拆除过程中如何选择爆破方案的技术难题,建立改进的Vague Sets-topsis综合评价指标模型,对爆破方案进行优选。首先对爆破方案中的关键参数建立评审指标集;然后利用逼近理想解的排序法,计算出各个方案的综... 为了解决复杂框架结构楼房爆破拆除过程中如何选择爆破方案的技术难题,建立改进的Vague Sets-topsis综合评价指标模型,对爆破方案进行优选。首先对爆破方案中的关键参数建立评审指标集;然后利用逼近理想解的排序法,计算出各个方案的综合优越度,从而确定各个爆破方案的优劣;最后以铁四院前大楼爆破为例,采用改进的Vague Sets-topsis理论模型对"内向折叠爆破"(S1)、"双向折叠爆破"(S2)和"单向折叠双切口爆破"(S3)等不同方案的关键参数进行综合对比分析,得到方案的最优排序为:S3>S2>S1。实际爆破拆除实例表明:S3拆除效果良好,证明采用改进的Vague Sets-topsis理论模型可以用于复杂框架结构楼房控制爆破拆除优选。 展开更多
关键词 爆破拆除 VAGUE sets-topsis理论 折叠爆破 爆破效果
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JULIA LIMITING DIRECTIONS OF ENTIRE SOLUTIONS OF COMPLEX DIFFERENTIAL EQUATIONS 被引量:2
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作者 Jun WANG Xiao YAO Chengchun ZHANG 《Acta Mathematica Scientia》 SCIE CSCD 2021年第4期1275-1286,共12页
For entire or meromorphic function f,a value θ∈[0,2π)is called a Julia limiting direction if there is an unbounded sequence{z_(n)}in the Julia set satisfying limn→∞ arg z_(n)=θ.Our main result is on the entire s... For entire or meromorphic function f,a value θ∈[0,2π)is called a Julia limiting direction if there is an unbounded sequence{z_(n)}in the Julia set satisfying limn→∞ arg z_(n)=θ.Our main result is on the entire solution f of P(z,f)+F(z)f^(s)=0,where P(z,f)is a differential polynomial of f with entire coefficients of growth smaller than that of the entire transcendental F,with the integer s being no more than the minimum degree of all differential monomials in P(z,f). We observe that Julia limiting directions of f partly come from the directions in which F grows quickly. 展开更多
关键词 Julia set meromorphic function Julia limiting direction complex differential equations
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CONE-DIRECTED CONTINGENT DERIVATIVES AND GENERALIZED PREINVEX SET-VALUED OPTIMIZATION 被引量:10
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作者 丘京辉 《Acta Mathematica Scientia》 SCIE CSCD 2007年第1期211-218,共8页
By using cone-directed contingent derivatives, the unified necessary and sufficient optimality conditions are given for weakly and strongly minimal elements respectively in generalized preinvex set-valued optimization.
关键词 Preinvex set-valued optimization cone-directed contingent derivative optimality conditions
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Image Filter for Removal of Impulse Noise Based on Directional Derivatives 被引量:2
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作者 KONG Tao, LI Jun-li, CHEN Gang (College of Information Science and Engineering, Ningbo University, Ningbo 315211, China) 《Computer Aided Drafting,Design and Manufacturing》 2008年第2期91-102,共12页
One of the most common image processing tasks involves the removal of noise from images. Noise can be introduced during image capture, during transmission, or during storage. For design purposes, noise sources are fre... One of the most common image processing tasks involves the removal of noise from images. Noise can be introduced during image capture, during transmission, or during storage. For design purposes, noise sources are frequently approximated by random variables with a known probability distribution. One common noise model corrupts a signal by introducing impulses. And the surface of the image disturbed by impulse noise displays many peaks or vales. According to the characteristic of impulse noise, a novel algorithm is proposed to the detection of impulse noise point from images based on directional derivatives. First, the theory of calculus on directional derivatives is introduced in detail. Then it is applied to the field of image to removing noise with the discrete form derived from its continuous mathematical model. And a number of contrasting simulations illustrate that our algorithm not only can preserve the structure information while removing impulse noise but also can mostly save the gray value of the pixels undisturbed by noise. In addition, the comparisons of the filtering performance for removing impulse noise are analyzed in detail in the case of different noise densities, and also show that the algorithm suggested outperforms the conventional filter algorithms such as mean filter, median filter and so on in speed and impulse noise reduction, especially in random-valued impulse noise reduction. So it is a very good alternative to the existing schemes. 展开更多
关键词 level sets directional derivatives impulse noise median filter
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A NOTE ON q-DIFFERENCE OPERATOR AND RELATED LIMIT DIRECTION
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作者 Yezhou LI Ningfang SONG 《Acta Mathematica Scientia》 SCIE CSCD 2018年第6期1678-1688,共11页
The growth of entire functions under the q-difference operators is studied inthis paper, and then some properties of Julia set of entire functions under the higher orderq-difference operators are obtained.
关键词 q-difference operator order limit direction Julia set
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新质生产力视域下高等教育强国建设的实践路向——基于64个国家的比较分析 被引量:1
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作者 李晓虹 张婷婷 王梓宁 《中国电化教育》 CSSCI 北大核心 2024年第9期41-50,共10页
探究新质生产力视域下高等教育强国建设的实践路向,对于推进高等教育高质量发展,提升国际竞争力具有重要意义。研究基于新质生产力视角,以64个国家为样本,构建出高等教育强国建设的分析框架,提炼出入学与人才培养能力、科研与学科建设... 探究新质生产力视域下高等教育强国建设的实践路向,对于推进高等教育高质量发展,提升国际竞争力具有重要意义。研究基于新质生产力视角,以64个国家为样本,构建出高等教育强国建设的分析框架,提炼出入学与人才培养能力、科研与学科建设能力、知识与技术创新能力、全球影响力4个条件变量,并运用模糊集定性比较分析方法(fs QCA),探索条件变量之间的“多向互动”以及不同条件组合对高等教育强国建设产生的“联合效应”。研究发现,单一条件无法单独构成高等教育强国建设的必要条件;高等教育强国高水平建设路径有两条,分别是高等教育人才培养与科研学科建设的内生发展型、知识与技术创新赋能高等教育全球影响力的外生驱动型。为加快推进高等教育强国建设,应突破单一要素攻关,发挥多要素间的耦合协同,共同推进高等教育强国建设;立足人才培养与科研学科建设,释放高等教育强国建设的内生动力,提升服务新质生产力的能力;聚焦知识技术创新与全球影响力,激活高等教育强国建设的外源动力,培育发展新质生产力的新动能。 展开更多
关键词 新质生产力 高等教育强国 模糊集定性比较分析(fsQCA) 实践路向
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基于重叠网格的船舶航向稳定性数值研究
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作者 贾爱鹏 彭晓星 +1 位作者 戚建祥 吴晓红 《武汉船舶职业技术学院学报》 2024年第3期88-91,110,共5页
基于重叠网格技术,采用URANS粘性数值模拟方法,对标准船模KVLCC2裸船体的航向稳定性进行了数值预报。基于STAR-CCM+平台,采用重叠网格技术和切割体网格,根据SIMMAN2014提供的标准算例,对KVLCC2进行了斜航运动和纯艏摇运动的数值模拟,得... 基于重叠网格技术,采用URANS粘性数值模拟方法,对标准船模KVLCC2裸船体的航向稳定性进行了数值预报。基于STAR-CCM+平台,采用重叠网格技术和切割体网格,根据SIMMAN2014提供的标准算例,对KVLCC2进行了斜航运动和纯艏摇运动的数值模拟,得到了横向力和转首力矩的历时曲线,并根据操纵性数学模型推倒出水动力导数,并计算稳定性衡准数,所有计算结果同模型试验数据吻合较好,验证了采用当前处理方法预报航向稳定性的可靠性。 展开更多
关键词 重叠网格 斜航运动 纯艏摇运动 航向稳定性
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高压直流输电保护定值整定依据及配合关系探讨
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作者 王俊生 蒲莹 张建锋 《电力系统自动化》 EI CSCD 北大核心 2024年第17期181-189,共9页
在中国30余年的高压直流输电工程实践中形成了一套高压直流输电保护系统定值体系。文中结合近年来在应用中出现的复杂案例,对以下保护的定值整定依据开展了进一步探讨:阀短路保护启动定值需避开与换流阀并联的阻容回路的充电电流;换流... 在中国30余年的高压直流输电工程实践中形成了一套高压直流输电保护系统定值体系。文中结合近年来在应用中出现的复杂案例,对以下保护的定值整定依据开展了进一步探讨:阀短路保护启动定值需避开与换流阀并联的阻容回路的充电电流;换流器过流保护过负荷段定值整定依据是直流控制系统失控造成直流运行电流超过控制的过负荷目标值,以及控制目标电流超过所设定的运行时间;直流低电压保护阈值及延时定值的整定需兼顾保护的后备功能,不确保与换相失败保护双桥原理长延时段配合。另外,深入探讨了交直流系统间、金属回线运行方式下直流保护间,以及高压线路再启动与低压再启动间的定值配合问题。最后,提出了高压直流输电保护系统的定值及定值间的配合应有一定的规范性和适度的灵活性的建议。 展开更多
关键词 高压直流输电 保护定值 短路保护 过流保护 再启动
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集值映射的Michel-Penot方向导数与Michel-Penot次微分
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作者 黄辉 陈智勇 《云南大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第5期819-828,共10页
采用标量化方法,研究集值映射的方向导数和次微分.借助Gerstewizt函数,给出了集值映射的Michel-Penot方向导数和Michel-Penot次微分的概念,研究了它们的性质,建立了它们的计算法则,并利用Michel-Penot次微分给出了无约束集值优化问题的... 采用标量化方法,研究集值映射的方向导数和次微分.借助Gerstewizt函数,给出了集值映射的Michel-Penot方向导数和Michel-Penot次微分的概念,研究了它们的性质,建立了它们的计算法则,并利用Michel-Penot次微分给出了无约束集值优化问题的优化条件. 展开更多
关键词 Michel-Penot方向导数 Michel-Penot次微分 集值映射 优化条件
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