期刊文献+
共找到230篇文章
< 1 2 12 >
每页显示 20 50 100
Meet Uniform Continuous Posets
1
作者 Xuxin MAO Luoshan XU 《Journal of Mathematical Research with Applications》 CSCD 2019年第5期459-468,共10页
In this paper, as a generalization of uniform continuous posets, the concept of meet uniform continuous posets via uniform Scott sets is introduced. Properties and characterizations of meet uniform continuous posets a... In this paper, as a generalization of uniform continuous posets, the concept of meet uniform continuous posets via uniform Scott sets is introduced. Properties and characterizations of meet uniform continuous posets are presented. The main results are:(1) A uniform complete poset L is meet uniform continuous iff ↑(U∩↓x) is a uniform Scott set for each x∈L and each uniform Scott set U;(2) A uniform complete poset L is meet uniform continuous iff for each x∈L and each uniform subset S, one has x∧∨ S =∨{x∧s|s∈S}. In particular, a complete lattice L is meet uniform continuous iff L is a complete Heyting algebra;(3) A uniform complete poset is meet uniform continuous iff every principal ideal is meet uniform continuous iff all closed intervals are meet uniform continuous iff all principal filters are meet uniform continuous;(4) A uniform complete poset L is meet uniform continuous if L1 obtained by adjoining a top element 1 to L is a complete Heyting algebra;(5) Finite products and images of uniform continuous projections of meet uniform continuous posets are still meet uniform continuous. 展开更多
关键词 uniform set uniform SCOTT set complete Heyting algebra MEET uniform CONTINUOUS POset principal ideal uniform CONTINUOUS projection
原文传递
Design and Structure Optimization of Plenum Chamber with Airfoil Baffle to Improve Its Outlet Velocity Uniformity in Heat Setting Machines
2
作者 钱淼 魏鹏郦 +2 位作者 林子杰 向忠 胡旭东 《Journal of Donghua University(English Edition)》 CAS 2023年第5期515-524,共10页
The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly af... The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly affecting the heat setting performance.In a traditional heat setting machine,the outlet airflow maldistribution of the plenum chamber still exists.In this study,a novel plenum chamber with an airfoil baffle was established to improve the uniformity of the velocity distribution at the outlet in a heat setting machine.The structural influence of the plenum chamber on the velocity distribution was investigated using a computational fluid dynamics program.It was found that a chamber with a smaller outlet partition thickness had a better outlet velocity uniformity.The structural optimization of the plenum chamber was conducted using the particle swarm optimization algorithm.The outlet partition thickness,the transverse distance and the longitudinal distance of the optimized plenum chamber were 20,686.2 and 274.6 mm,respectively.Experiments were carried out.The experimental and simulated results showed that the optimized plenum chamber with an airfoil baffle could improve the outlet velocity uniformity.The air outlet velocity uniformity index of the optimized plenum chamber with an airfoil baffle was 4.75%higher than that of the plenum chamber without an airfoil baffle and 5.98%higher than that of the conventional chamber with a square baffle in a commercial heat setting machine. 展开更多
关键词 velocity distribution uniformity structure optimization numerical simulation AIRFOIL plenum chamber heat setting
在线阅读 下载PDF
Image segmentation by level set evolution with region consistency constraint 被引量:5
3
作者 ZHONG Li ZHOU Yuan-feng +2 位作者 ZHANG Xiao-feng GUO Qiang ZHANG Cai-ming 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2017年第4期422-442,共21页
Image segmentation is a key and fundamental problem in image processing,computer graphics,and computer vision.Level set based method for image segmentation is used widely for its topology flexibility and proper mathem... Image segmentation is a key and fundamental problem in image processing,computer graphics,and computer vision.Level set based method for image segmentation is used widely for its topology flexibility and proper mathematical formulation.However,poor performance of existing level set models on noisy images and weak boundary limit its application in image segmentation.In this paper,we present a region consistency constraint term to measure the regional consistency on both sides of the boundary,this term defines the boundary of the image within a range,and hence increases the stability of the level set model.The term can make existing level set models significantly improve the efficiency of the algorithms on segmenting images with noise and weak boundary.Furthermore,this constraint term can make edge-based level set model overcome the defect of sensitivity to the initial contour.The experimental results show that our algorithm is efficient for image segmentation and outperform the existing state-of-art methods regarding images with noise and weak boundary. 展开更多
关键词 level set evolution image segmentation uniformity testing multiple level contours region consistency constraint
在线阅读 下载PDF
A NOTE IN APPROXIMATIVE COMPACTNESS AND MIDPOINT LOCALLY K-UNIFORM ROTUNDITY IN BANACH SPACES 被引量:4
4
作者 刘春燕 张子厚 周宇 《Acta Mathematica Scientia》 SCIE CSCD 2018年第2期643-650,共8页
In this article, we prove the following results: (1) A Banach space X is weak midpoint locally k-uniformly rotund if and only if every closed ball of X is an approximatively weakly compact k-Chebyshev set; (2) A ... In this article, we prove the following results: (1) A Banach space X is weak midpoint locally k-uniformly rotund if and only if every closed ball of X is an approximatively weakly compact k-Chebyshev set; (2) A Banach space X is midpoint locally k-uniformly rotund if and only if every closed ball of X is an approximatively compact k-Chebyshev set. 展开更多
关键词 k-Chebyshev set approximatively weak compactness approximative compactness weak midpoint locally k-uniform rotundity midpoint locally k-uniform rotundity k-strict rotundity
在线阅读 下载PDF
ON RADII OF ABSORBING SETS FOR KURAMOTOSIVASHINSKY EQUATION
5
作者 王冠香 刘曾荣 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1999年第7期28-37,共10页
In this article sharper estimates on the radii of absorbing sets for the Kuramoto_Sivashinsky equation are given. It is proved that radii of absorbing sets will decay to zero as the coefficient of viscosity tends to a... In this article sharper estimates on the radii of absorbing sets for the Kuramoto_Sivashinsky equation are given. It is proved that radii of absorbing sets will decay to zero as the coefficient of viscosity tends to a certain critical value, which is more reasonable in the physical sence compared with classical results. 展开更多
关键词 K_S equation uniform estimate absorbing set
在线阅读 下载PDF
INTERSECTION OF MCMULLEN SET WITH ITS RATIONAL TRANSLATION
6
作者 Meifeng Dai Lixin Tang 《Analysis in Theory and Applications》 2008年第1期29-39,共11页
In this paper, we study the intersection of Mcmullen set with its rational translation. The main difficulty is that the generating structure of the intersection. By the radix expansion of translating vector, we give i... In this paper, we study the intersection of Mcmullen set with its rational translation. The main difficulty is that the generating structure of the intersection. By the radix expansion of translating vector, we give its fractal characterization. We find that the Hausdorff measure of these sets forms a discrete spectrum whose non-zero values come only from translating the vector (x,y) with its radix expansion. 展开更多
关键词 Mcmullen set m-part uniform Cantor set INTERSECTION Hausdorff measure
在线阅读 下载PDF
On the Uniformly Balancedness of Graphs
7
作者 WEN Yi-hui 《Chinese Quarterly Journal of Mathematics》 CSCD 2010年第4期565-571,共7页
In this paper,the definition of absolutely balanced and uniformly balanced for graphs are introduced,the difference between balance graphs are pointed out.Using(p,p+1)-graph as an example,we explained the existence... In this paper,the definition of absolutely balanced and uniformly balanced for graphs are introduced,the difference between balance graphs are pointed out.Using(p,p+1)-graph as an example,we explained the existence of this difference and obtained some new results. 展开更多
关键词 balance graph absolutely balance uniformly balance balance index set
在线阅读 下载PDF
Maximal elements and generalized games involving condensing mappings in locally FC-uniform spaces and applications(Ⅰ)
8
作者 丁协平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第12期1561-1568,共8页
First, the notions of the measure of noncompactness and condensing setvalued mappings are introduced in locally FC-uniform spaces without convexity structure. A new existence theorem of maximal elements of a family of... First, the notions of the measure of noncompactness and condensing setvalued mappings are introduced in locally FC-uniform spaces without convexity structure. A new existence theorem of maximal elements of a family of set-valued mappings involving condensing mappings is proved in locally FC-uniform spaces. As applications, some new equilibrium existence theorems of generalized game involving condensing mappings are established in locally FC-uniform spaces. These results improve and generalize some known results in literature to locally FC-uniform spaces. Some further applications of our results to the systems of generalized vector quasi-equilibrium problems will be given in a follow-up paper. 展开更多
关键词 condensing set-valued mapping maximal element generalized game equi-librium locally FC-uniform spaces
在线阅读 下载PDF
基于改进的NSGA-Ⅱ算法的动态武器目标分配研究
9
作者 郑巍 郭俊 +3 位作者 潘浩 熊小平 樊鑫 肖鹏 《兵器装备工程学报》 北大核心 2025年第12期132-140,共9页
在现代空战中,武器与目标的动态分配(dynamic weapon target assignment,DWTA)策略对于战斗结果具有决定性的影响。现有的NSGA-Ⅱ算法在处理这一问题时,会面临收敛精度不足且速度较慢这一个显著问题。为应对这一挑战,本文中提出了一种... 在现代空战中,武器与目标的动态分配(dynamic weapon target assignment,DWTA)策略对于战斗结果具有决定性的影响。现有的NSGA-Ⅱ算法在处理这一问题时,会面临收敛精度不足且速度较慢这一个显著问题。为应对这一挑战,本文中提出了一种改进的NSGA-Ⅱ算法(MYNSGA-Ⅱ),以更好地处理复杂的DWTA问题。首先,为了种群在解空间中的分布更加合理,引入了佳点集的概念,旨在对算法的种群策略进行优化,从而提升了搜索效率和效果。其次,为了将变异算子的作用与代数关联起来,采用了非均匀变异方式,这一改进,使得算法可以在前期变异的范围会较大,随着演化代数的增加,变异范围越来越小,增加算法的微调能力。最后,为了提高算法的收敛速度,借鉴粒子群算法,从而提出了引导式杂交,目的是使种群个体往好的方向进化。实验仿真比较了MYNSGA-Ⅱ,NSGA-Ⅱ和MOPSO算法,结果表明,MYNSGA-Ⅱ在寻找真实Pareto前沿方面更为精确,有效提升了DWTA问题的求解效率和解决方案的质量,展现了其在现代空战武器目标分配中的优越性。 展开更多
关键词 动态武器目标分配 NSGA-Ⅱ 佳点集 非均匀变异 PARETO前沿
在线阅读 下载PDF
EXISTENCE RESULT FOR FRACTIONAL STATE-DEPENDENT SWEEPING PROCESSES
10
作者 Shengda ZENG Abderrahim BOUACH Tahar HADDAD 《Acta Mathematica Scientia》 2025年第4期1471-1481,共11页
This paper addresses the evolution problem governed by the fractional sweeping process with prox-regular nonconvex constraints.The values of the moving set are time and state-dependent.The aim is to illustrate how a f... This paper addresses the evolution problem governed by the fractional sweeping process with prox-regular nonconvex constraints.The values of the moving set are time and state-dependent.The aim is to illustrate how a fixed point method can establish an existence theorem for this fractional nonlinear evolution problem.By combining Schauder’s fixed point theorem with a well-posedness theorem when the set C is independent of the state u(i.e.C:=C(t),as presented in[22,23]),we prove the existence of a solution to our quasi-variational fractional sweeping process in infinite-dimensional Hilbert spaces.Similar to the conventional state-dependent sweeping process,achieving this result requires a condition on the size of the Lipschitz constant of the moving set relative to the state. 展开更多
关键词 fractional differential inclusion Moreau's sweeping process prox-regular sets fixed point
在线阅读 下载PDF
Lattice point partition designs for experiments with mixture
11
作者 LI Jun-peng LI Guang-hui ZHANG Chong-qi 《Applied Mathematics(A Journal of Chinese Universities)》 2025年第3期725-740,共16页
The upper bound on the model error will be decreased when the mean square error and the maximum distance deviation are sufficiently small in the uniform designs for mixture experiments and the design is more robust fo... The upper bound on the model error will be decreased when the mean square error and the maximum distance deviation are sufficiently small in the uniform designs for mixture experiments and the design is more robust for the model.However,the analytical expressions of MSED and MD are currently only available in the hypercube,but both types of deviations in other studies are just approximations.Although it can obtain good approximations in the low-dimensional case,the calculation will be more complicated for an experiment with more variables.Therefore,in this paper,an algorithm based on lattice point partitioning design is proposed to obtain the analytical expression of the MSED and MD in the region covered by the lattice points.Furthermore,the design’s optimality is considered and illustrated by examples under the same uniformity. 展开更多
关键词 Lattice point set D-OPTIMALITY uniform design mixture experiments
在线阅读 下载PDF
Nearest Point Maps onto Uniformly Convex Sets
12
作者 Qingjin Cheng Cuiling Wang Jianjian Wang 《Acta Mathematica Sinica,English Series》 2025年第5期1315-1327,共13页
Let K be a(bounded)closed uniformly convex subset of a Banach space X.We show that(i)the nearest point map is well-defined and always continuous from X onto K,(ii)there is a reflexive space Y with a uniform rotund in ... Let K be a(bounded)closed uniformly convex subset of a Banach space X.We show that(i)the nearest point map is well-defined and always continuous from X onto K,(ii)there is a reflexive space Y with a uniform rotund in every direction norm such that Y contains K as a subset and the nearest point map PK:Y→K is uniformly continuous from any bounded set containing K onto K. 展开更多
关键词 uniformly convex set nearest point map RETRACT Banach space
原文传递
涡轮钻具四支点接触球轴承载荷分析与级数优选
13
作者 熊紫云 《现代机械》 2025年第3期44-48,共5页
针对涡轮钻具中,四支点接触球轴承组承载不均匀的问题,基于均载理论,结合有限元仿真分析方法,在恒定轴向载荷情况下,对不同级轴承组承受的载荷分布情况进行分析,得出轴承组的最佳级数,使得轴承组的承载能力达到最优。结果表明:最靠近施... 针对涡轮钻具中,四支点接触球轴承组承载不均匀的问题,基于均载理论,结合有限元仿真分析方法,在恒定轴向载荷情况下,对不同级轴承组承受的载荷分布情况进行分析,得出轴承组的最佳级数,使得轴承组的承载能力达到最优。结果表明:最靠近施加载荷处的第一排轴承承受载荷最大,轴承排数越大的轴承,承受的载荷越小。在轴向载荷一定时,2~15级轴承组中第一排轴承承受的载荷逐渐减小,而从15级到20级轴承组中第一排轴承承受的载荷占比下降幅度较小,结合经济角度考虑,15级轴承组是178涡轮钻具四支点接触球轴承组的最佳级数。 展开更多
关键词 涡轮钻具 轴承组 均载 承载能力
在线阅读 下载PDF
非凸变分不等式的四步投影算法及其收敛性分析 被引量:3
14
作者 张亮 吴至友 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2014年第10期109-113,共5页
利用非凸变分不等式和不动点问题的等价关系,给出了一个新的求解非凸变分不等式的四步投影算法.该算法在现有的三步迭代算法基础上,利用校正方法建立了第四步迭代公式.最后在适当条件下证明了该算法的收敛性,所得结论推广了该领域内的... 利用非凸变分不等式和不动点问题的等价关系,给出了一个新的求解非凸变分不等式的四步投影算法.该算法在现有的三步迭代算法基础上,利用校正方法建立了第四步迭代公式.最后在适当条件下证明了该算法的收敛性,所得结论推广了该领域内的一些最新结果. 展开更多
关键词 非凸变分不等式 一致临近正则集 ξ 强单调算子 η-Lipschitz 连续算子 四步投影算法
原文传递
一类新的推广非凸变分不等式的平行投影算法(英文) 被引量:1
15
作者 张亮 吴至友 《重庆师范大学学报(自然科学版)》 CAS CSCD 北大核心 2015年第1期6-11,共6页
对定义在一致临近正则集上的一类新的推广的非凸变分不等式,本文提出了一个平行投影算法,算法的收敛点既是该变分不等式的解,又是两个Lipschitz映像的不动点。进一步,本文在适当条件下证明了该算法的收敛性。本文所得结论改进并推广了... 对定义在一致临近正则集上的一类新的推广的非凸变分不等式,本文提出了一个平行投影算法,算法的收敛点既是该变分不等式的解,又是两个Lipschitz映像的不动点。进一步,本文在适当条件下证明了该算法的收敛性。本文所得结论改进并推广了有关变分不等式和相关最优化问题的一些结果。 展开更多
关键词 推广的非凸变分不等式 一致临近正则集 松弛强制映像 强单调算子 Lipschitz连续映像
原文传递
遗传交叉运算的可达性研究 被引量:16
16
作者 张军英 许进 保铮 《自动化学报》 EI CSCD 北大核心 2002年第1期120-125,共6页
定义了遗传交叉运算的可达性及其达概率的概念 ,指出传统的单点交叉运算只使得参与交叉运算的个体对所张成子空间的边缘是可达的 ,且为非均匀可达的 ,从而大大地限制了该运算的搜索能力 .为此 ,讨论了一致交叉运算的可达性 ,指出它使得... 定义了遗传交叉运算的可达性及其达概率的概念 ,指出传统的单点交叉运算只使得参与交叉运算的个体对所张成子空间的边缘是可达的 ,且为非均匀可达的 ,从而大大地限制了该运算的搜索能力 .为此 ,讨论了一致交叉运算的可达性 ,指出它使得参与交叉运算的个体对所张成子空间的全空间都是可达的 ,且可以构造交叉字串使得它是均匀可达的 ,从而有效提高算法的搜索能力 . 展开更多
关键词 标准交叉运算 一次交叉运算 个体 群体 可达概率 遗传算法 可达性
在线阅读 下载PDF
集值模糊测度的自连续性 被引量:12
17
作者 高娜 李艳红 王贵君 《四川师范大学学报(自然科学版)》 CAS CSCD 北大核心 2008年第4期386-389,共4页
在m维正欧式空间的子集类上引入一种新的序结构.定义了集合列依序收敛的概念,讨论了集值模糊测度的自连续、一致自连续、逆自连续和一致逆自连续性,给出了逆零可加、逆自连续、一致逆自连续等定义,进而研究它们的蕴涵关系,从而丰富了集... 在m维正欧式空间的子集类上引入一种新的序结构.定义了集合列依序收敛的概念,讨论了集值模糊测度的自连续、一致自连续、逆自连续和一致逆自连续性,给出了逆零可加、逆自连续、一致逆自连续等定义,进而研究它们的蕴涵关系,从而丰富了集值模糊测度和集值模糊积分的理论. 展开更多
关键词 集值模糊测度 自连续 一致自连续 逆零可加 一致逆自连续
在线阅读 下载PDF
一致极小集及其对一致连续偏序集的应用 被引量:7
18
作者 阮小军 徐晓泉 《模糊系统与数学》 CSCD 北大核心 2014年第4期80-83,共4页
对于一致极小集,讨论了它的一些性质及与一致连续偏序集的关系,给出了一致连续偏序集中保一致极小集映射的一些等价刻划。最后,得到了关于保一致极小集映射的扩张定理。
关键词 一致极小集 一致连续偏序集 一致基
原文传递
早中侏罗世大鄂尔多斯古地理重建与内陆拗陷的发育演化 被引量:48
19
作者 程守田 黄焱球 付雪洪 《沉积学报》 CAS CSCD 北大核心 1997年第4期43-49,共7页
通过沉积构成、古流体系和相带分布等沉积的成因联系及沉积学比较分析,论证了现今鄂尔多斯与其以东山西宁武、大同等地下中侏罗统同期地层原始沉积充填的统一性,证实了它们属于同一个大鄂尔多斯沉积盆地。并按照四个时期重建和阐明了... 通过沉积构成、古流体系和相带分布等沉积的成因联系及沉积学比较分析,论证了现今鄂尔多斯与其以东山西宁武、大同等地下中侏罗统同期地层原始沉积充填的统一性,证实了它们属于同一个大鄂尔多斯沉积盆地。并按照四个时期重建和阐明了早中侏罗世盆地沉积古地理,从而揭示了大鄂尔多斯拗陷—隆升—再拗陷的形成演化的构造阶段性及其充填动力学背景的迁移性。关于内陆拗陷构造背景的探讨。 展开更多
关键词 盆地 沉积 古地理 内陆拗陷 发育演化 侏罗世
在线阅读 下载PDF
满足均匀分布的不确定数据关联规则挖掘算法 被引量:18
20
作者 陈爱东 刘国华 +3 位作者 费凡 周宇 万小妹 貟慧 《计算机研究与发展》 EI CSCD 北大核心 2013年第S1期186-195,共10页
云计算为大数据提供了展示和共享的平台.为了防止隐私泄露,这些数据中往往包含人为添加的不确定因素,如何挖掘这些不确定数据是大数据共享亟待解决的问题.在用于共享的大数据中,不确定数据通过对精确数据的泛化处理来实现,具有均匀分布... 云计算为大数据提供了展示和共享的平台.为了防止隐私泄露,这些数据中往往包含人为添加的不确定因素,如何挖掘这些不确定数据是大数据共享亟待解决的问题.在用于共享的大数据中,不确定数据通过对精确数据的泛化处理来实现,具有均匀分布特性,这一特性不利于精确查询,但可为关联规则的挖掘提供便利条件.首先,依据泛化值之间可能的相交或包含关系,将泛化值进行分层聚类,为了保存与不确定数据集挖掘相关的重要信息,给出了构建不确定频繁模式树的算法,在此基础上,提出了频繁项集挖掘子算法(data mining algorithm for uncertain frequent item-sets,UFI-DM)和关联规则生成子算法(algorithm for generating association rules,GAR),分别用于挖掘频繁项集和生成关联规则,最后,通过理论分析和实验比对,论证了算法的可行性和有效性. 展开更多
关键词 大数据 均匀分布不确定数据 数据挖掘 关联规则 频繁项集
在线阅读 下载PDF
上一页 1 2 12 下一页 到第
使用帮助 返回顶部