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Determination of Weak Points Based on Risk Theory and Application to Transmission Network Planning 被引量:1
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作者 LIU Zhe JIA Hongjie +1 位作者 ZENG Yuan QIN Chao 《Transactions of Tianjin University》 EI CAS 2012年第1期38-45,共8页
In the traditional power transmission network planning,deterministic analysis methods are widely used.In such methods,all contingencies are deemed to have the same occurrence probability,which is not reasonable.In thi... In the traditional power transmission network planning,deterministic analysis methods are widely used.In such methods,all contingencies are deemed to have the same occurrence probability,which is not reasonable.In this paper,risk assessment is introduced to the process of transmission network planning considering the probabilistic characteristics of contingencies.Risk indices are given to determine the weak points of the transmission network based on local information,such as bus risk,line overload risk,contingency severity.The indices are calculated by the optimal cost control method based on risk theory,which can help planners to quickly determine weak points in the planning and find solution to them.For simplification,only line overload violation is considered.Finally,the proposed method is validated by an IEEE-RTS test system and a real power system in China from two aspects.In the first case,the original system is evaluated by the proposed method to find the weak points,and then four planning schemes are established,among which the best scheme is selected.In the second case,four initial planning schemes are established by combining the experiences of planners,and after the evaluation by using the proposed method,the best planning scheme is improved based on the information of weak points in the initial schemes,and the risk of improved scheme is reduced from 42 531.86 MW·h per year to 4 431.26 MW·h per year. 展开更多
关键词 risk assessment weak point transmission network planning risk theory
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Spaces with σ-point-discrete N_0-weak bases 被引量:1
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作者 SHEN Rong-xin LIN Shou 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2013年第1期116-126,共11页
It is discussed in this paper the spaces with σ-point-discrete N_0-weak bases. The main results are: (1) A space X has a σ-compact-finite N_0-weak base if and only if X is a k-space with a σ-point-discrete N_0-w... It is discussed in this paper the spaces with σ-point-discrete N_0-weak bases. The main results are: (1) A space X has a σ-compact-finite N_0-weak base if and only if X is a k-space with a σ-point-discrete N_0-weak base; (2) Under (CH), every separable space with a σ-point-discrete N_0-weak base has a countable N_0-weak base. 展开更多
关键词 N_0-weak base σ-point-discrete network σ-compact-finite network separable space.
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Points of Coincidence for Weakly Compatible Pair of Mappings in Cone Metric Spaces 被引量:1
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作者 SONG Jiping 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2015年第1期8-14,共7页
In this paper, some new existence and uniqueness of points of coincidence of weakly compatible pair of mappings is obtained, which does not satisfy continuity and commutativity. The conditions are weaker than the usua... In this paper, some new existence and uniqueness of points of coincidence of weakly compatible pair of mappings is obtained, which does not satisfy continuity and commutativity. The conditions are weaker than the usual conditions in cone metric spaces. 展开更多
关键词 weakly compatible pair of mappings point of coincidence common fixed point cone metric space
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Unique Common Fixed Points for Two Weakly C~*-contractive Mappings on Partially Ordered 2-metric Spaces 被引量:1
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作者 Piao Yong-jie 《Communications in Mathematical Research》 CSCD 2018年第1期77-88,共12页
In this paper, we give existence theorems of common fixed points for two mappings with a weakly C*-contractive condition on partially ordered 2-metric spaces and give a sufficient condition under which there exists a ... In this paper, we give existence theorems of common fixed points for two mappings with a weakly C*-contractive condition on partially ordered 2-metric spaces and give a sufficient condition under which there exists a unique common fixed point. 展开更多
关键词 2-metric space weak C*-contraction common fixed point
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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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弱纹理环境下点线融合鲁棒视觉SLAM算法
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作者 杨官学 刘岳松 +2 位作者 刘慧 沈跃 沈亚运 《计算机工程与应用》 北大核心 2026年第2期313-324,共12页
针对弱纹理和变光照环境下基于点特征的视觉SLAM(simultaneous localization and mapping)算法轨迹漂移的问题,提出了一种基于改进自适应阈值ELSED算法(Adaptive-ELSED)的快速点线融合双目视觉SLAM算法。通过在ELSED算法中添加自适应阈... 针对弱纹理和变光照环境下基于点特征的视觉SLAM(simultaneous localization and mapping)算法轨迹漂移的问题,提出了一种基于改进自适应阈值ELSED算法(Adaptive-ELSED)的快速点线融合双目视觉SLAM算法。通过在ELSED算法中添加自适应阈值矩阵,动态调整不同光照条件下梯度阈值,并使用长度抑制和短线合并策略,提高线特征的质量。利用基于双目几何约束和图像结构相似性(SSIM)进行快速线段特征三角化。基于历史位姿及误差分析获取初始位姿,通过自适应因子实现光束法平差过程中点线特征的更有效融合。实验结果表明,所提算法在提高线特征质量的同时,耗时仅为LSD算法的50%,线特征匹配速度较传统LBD算法提升67%,挑战性场景下轨迹误差较ORB-SLAM3降低62.2%,系统的平均跟踪帧率为27帧/s,在保证系统实时性的同时,显著提升了系统在弱纹理、变光照环境下的精度和鲁棒性。 展开更多
关键词 双目视觉 弱纹理 视觉同步定位与地图构建(SLAM) 点线特征 特征匹配
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基于薄弱点定位的电力电子化交流配用电系统振荡抑制方法
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作者 沈冰 柴炜 +2 位作者 王凯 李骁远 吕敬 《上海交通大学学报》 北大核心 2026年第1期32-41,I0001,I0002,共12页
近年来,电力电子变流器因其可控性与灵活性等特点,在交流配用电系统中得到大量应用.然而,随着电力电子设备接入比例不断提高,高度电力电子化带来的振荡稳定性问题成为目前新型配用电系统面临的关键技术难题之一.在实际交流配用电系统中,... 近年来,电力电子变流器因其可控性与灵活性等特点,在交流配用电系统中得到大量应用.然而,随着电力电子设备接入比例不断提高,高度电力电子化带来的振荡稳定性问题成为目前新型配用电系统面临的关键技术难题之一.在实际交流配用电系统中,次/超同步振荡问题频发,严重影响工业生产和电网安全稳定运行.为此,提出一种基于薄弱点定位的电力电子化交流配用电系统振荡抑制方法.首先,构建电力电子化交流配用电系统的频域阻抗网络,建立该系统的节点导纳矩阵模型,基于主导特征值分析多机系统的次/超同步稳定性.然后,进一步计算得到系统薄弱模态的节点参与因子矩阵,确定系统薄弱节点,并定义节点耦合度,量化评估节点间的交互作用强弱;最后,提出一种基于直流电压反馈有源阻尼的振荡抑制方法.通过某实际电力电子化交流配用电系统算例验证了所提方法的有效性. 展开更多
关键词 电力电子化电力系统 次同步振荡 薄弱点定位 节点参与因子 频域模态分析
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井冈山国家农高区创建与高质量发展的现状、问题与对策研究
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作者 彭柳林 马烨 《江西农业学报》 2026年第1期110-116,共7页
国家农业高新技术产业示范区作为区域农业科技创新策源地、农业创新驱动发展先行区和农业供给侧结构性改革试验区,是引领农业高质量发展的重要政策创新。井冈山农高区以“南方红壤高效农业”为主题、绿色食品为主导产业,自2020年启动升... 国家农业高新技术产业示范区作为区域农业科技创新策源地、农业创新驱动发展先行区和农业供给侧结构性改革试验区,是引领农业高质量发展的重要政策创新。井冈山农高区以“南方红壤高效农业”为主题、绿色食品为主导产业,自2020年启动升建以来,在基础设施、科创资源、产业集聚等方面取得了阶段性成效,但仍面临科技创新能力不足、主导产业竞争力偏弱、体制机制不够顺畅、保障体系不够健全等问题。为全方位推进井冈山国家农高区高标准创建与高质量发展,在总结已获批国家农高区经验启示的基础上,从“挖掘自身优势—提升科创能力—做强主导产业—健全保障机制”四个维度提出了对策建议。 展开更多
关键词 井冈山农高区 高质量发展 比较优势 短板弱项 对策建议
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基于BCWSM-AHP模型的复杂配电网薄弱节点识别精度提升研究 被引量:1
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作者 王凌云 李洋 +2 位作者 鲍刚 王艳阳 赵铜鑫 《智慧电力》 北大核心 2025年第8期46-53,共8页
为提升复杂配电网中受环网结构与分布式电源影响的薄弱节点识别精度,首次融合二项系数加权法与层次分析法,提出基于二项系数加权层次分析(BCWSM-AHP)模型的识别精度提升方法。该模型基于复杂网络理论,构建了包括改进节点度指标、改进节... 为提升复杂配电网中受环网结构与分布式电源影响的薄弱节点识别精度,首次融合二项系数加权法与层次分析法,提出基于二项系数加权层次分析(BCWSM-AHP)模型的识别精度提升方法。该模型基于复杂网络理论,构建了包括改进节点度指标、改进节点PageRank指标、改进节点电气介数指标、潮流增量冲击指标及节点电压稳定指标等5大新型指标的评估体系,可全面评估复杂配电网的薄弱节点。通过二项式系数加权法优化准则层权重分配,将专家判断的主观一致性指数从0.047降至0.015,显著降低了传统层次分析法(AHP)中的主观性。算例分析表明,BCWSM-AHP模型能更精准定位有源配电网的关键薄弱节点。 展开更多
关键词 薄弱点识别 复杂配电网 复杂网络理论 层次分析法
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WEAK LIMITS OF EMPIRICAL MEASURES FOR A FAMILY OF DIFFUSION PROCESSES
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作者 席福宝 赵丽琴 《Acta Mathematica Scientia》 SCIE CSCD 2004年第2期301-306,共6页
This paper considers diffusion processes {X^(?)(t)} on R^2, which are perturbations of dynamical system {X(t)} (dX(t)=b(X(t))dt) on R^2. By means of weak convergence of probability measures, the authors characterize t... This paper considers diffusion processes {X^(?)(t)} on R^2, which are perturbations of dynamical system {X(t)} (dX(t)=b(X(t))dt) on R^2. By means of weak convergence of probability measures, the authors characterize the limit behavior for empirical measures of {X^(?)(t)} in a neighborhood domain of saddle point of the dynamical system as the perturbations tend to zero. 展开更多
关键词 Empirical measures weak convergence saddle point
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基于频域模态法的新能源电力系统振荡稳定性评估 被引量:1
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作者 高磊 马骏超 +3 位作者 吕敬 刘佳宁 王晨旭 蔡旭 《上海交通大学学报》 北大核心 2025年第6期821-835,I0008,I0009,共17页
随着新能源接入比例的不断提高,电力系统的次/超同步振荡风险加剧,准确评估新能源电力系统的振荡稳定性是保障系统安全稳定运行的关键.首先,研究了一种基于频域模态分析的新能源电力系统振荡稳定性评估方法,该方法通过建立新能源机组和... 随着新能源接入比例的不断提高,电力系统的次/超同步振荡风险加剧,准确评估新能源电力系统的振荡稳定性是保障系统安全稳定运行的关键.首先,研究了一种基于频域模态分析的新能源电力系统振荡稳定性评估方法,该方法通过建立新能源机组和场站、传输线、同步机、变压器等关键设备和场站的频域阻抗或导纳模型,根据实际系统拓扑构建系统级频域网络模型.然后,通过求解回路阻抗矩阵或节点导纳矩阵行列式的零点来评估新能源电力系统的振荡稳定性,通过计算弱阻尼振荡模式的节点参与因子矩阵定位系统薄弱点,为振荡抑制措施的实施提供依据.以国内华东地区某实际新能源电力系统为例,利用频域模态分析法评估新能源接入容量和电网运行工况变化下系统的振荡稳定性.最后,利用PSCAD/EMTDC软件搭建该系统的时域仿真模型,验证了理论分析的正确性. 展开更多
关键词 新能源电力系统 振荡稳定性 频域网络 频域模态分析 稳定性评估 薄弱点定位
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针刺经穴对脾胃虚弱型功能性消化不良患者血清5-羟色胺、血管活性肽及胰高血糖素样肽-1的影响 被引量:5
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作者 李朵朵 岳增辉 刘未艾 《中医杂志》 北大核心 2025年第13期1357-1362,共6页
目的观察针刺经穴治疗脾胃虚弱型功能性消化不良(FD)的临床疗效并探讨其可能作用机制。方法将60例脾胃虚弱型FD患者随机分为针刺经穴组和多潘立酮组,每组30例。针刺经穴组取经穴足三里、内关、公孙、阴陵泉,平补平泻,单侧取穴,左右交替... 目的观察针刺经穴治疗脾胃虚弱型功能性消化不良(FD)的临床疗效并探讨其可能作用机制。方法将60例脾胃虚弱型FD患者随机分为针刺经穴组和多潘立酮组,每组30例。针刺经穴组取经穴足三里、内关、公孙、阴陵泉,平补平泻,单侧取穴,左右交替,每日1次,每次30 min,5次1个疗程,每个疗程间隔2日。多潘立酮组给予多潘立酮片,每次1片,每日3次,饭前15~30 min口服。两组疗程均为4周。比较两组治疗前及治疗4、8周后两组患者的临床症状(包括餐后饱胀不适、早饱感、上腹痛、上腹部烧灼不适)评分,检测血清中5-羟色胺(5-HT)、血管活性肽(VIP)及胰高血糖素样肽-1(GLP-1)含量;治疗后评价临床疗效。结果与本组治疗前比较,两组患者治疗4、8周后餐后饱胀不适、早饱感、上腹痛、上腹部烧灼不适评分均降低,血清中5-HT、VIP及GLP-1含量亦明显降低(P<0.05);治疗4周后,针刺经穴组各症状评分,血清中5-HT、GLP-1水平明显低于多潘立酮组(P<0.05);治疗8周后,针刺经穴组餐后饱胀不适、早饱感、上腹痛症状评分,血清中5-HT、VIP水平明显低于多潘立酮组(P<0.05)。治疗后针刺经穴组临床总有效率为96.67%(29/30),优于多潘立酮组的86.67%(26/30,P>0.05)。结论针刺经穴治疗脾胃虚弱型FD可显著改善临床症状,其机制可能与降低患者血清5-HT、VIP及GLP-1含量相关。 展开更多
关键词 功能性消化不良 脾胃虚弱 经穴 针刺 5-羟色胺 血管活性肽 胰高血糖素样肽-1
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A Weak Convergence Theorem for A Finite Family of Asymptotically Nonexpansive Mappings
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作者 Kan Xu-zhou Guo Wei-ping 《Communications in Mathematical Research》 CSCD 2014年第4期295-300,共6页
The purpose of this paper is to prove a new weak convergence theorem for a finite family of asymptotically nonexpansive mappings in uniformly convex Banach space.
关键词 asymptotically nonexpansive mapping weak convergence common fixed point uniformly convex Banach space
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A Fixed Point Theorem in Intuitionistic Fuzzy Metric Spaces by Using New Commutativity Condition
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作者 Sushil Sharma Bhavana Deshpande 《模糊系统与数学》 CSCD 北大核心 2010年第4期151-161,共11页
We prove a common fixed point theorem for discontinuous,noncompatible mappings on noncomplete intuitionistic fuzzy metric spaces by using a new commutativity condition.We validate our main result by an example.
关键词 Triangular Norms Triangular Conorms Intuitionistic Fuzzy Meuric Spaces (DS)-weak Commutativity Common Fixed points
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Weak Convergence Theorems for Nonself Mappings 被引量:1
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作者 LIU YONG-QUAN GUO WEI-PING Ji You-qing 《Communications in Mathematical Research》 CSCD 2015年第1期15-22,共8页
Let E be a real uniformly convex and smooth Banach space, and K be a nonempty closed convex subset of E with P as a sunny nonexpansive retraction. Let T1, T2 : K → E be two weakly inward nonself asymptotically nonex... Let E be a real uniformly convex and smooth Banach space, and K be a nonempty closed convex subset of E with P as a sunny nonexpansive retraction. Let T1, T2 : K → E be two weakly inward nonself asymptotically nonexpansive mappings with respect to P with a sequence {kn^(i)} [1, ∞) (i = 1, 2), and F := F(T1)∩ F(T2) ≠ 0. An iterative sequence for approximation common fixed points of the two nonself asymptotically nonexpansive mappings is discussed. If E has also a Frechet differentiable norm or its dual E^* has Kadec-Klee property, then weak convergence theorems are obtained. 展开更多
关键词 asymptotically nonexpansive nonself-mapping weak formly convex Banach space common fixed point smooth Banach convergence urnspace
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A Point-of-Care Test System for Biochemical Blood Analysis Based on ADUC824
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作者 Hui Wang Qing Tian +3 位作者 Liying Jiang Chunxiu Liu Zonghui Guo Xinxia Cai 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第A03期75-79,共5页
A point-of-care test system has been studied in this paper.It was used to determine substances in blood such as Hemoglobin (HB),Aspartate Aminotransferase (AST),Creatine Kinase (CK) and so on.Based on the principle ... A point-of-care test system has been studied in this paper.It was used to determine substances in blood such as Hemoglobin (HB),Aspartate Aminotransferase (AST),Creatine Kinase (CK) and so on.Based on the principle of amperometric determination,the research on detecting weak current signals was carried on.At the same time as to the weak signals (nA level),magnifying,sampling and processing the signals were also studied.Controlled by ADUC824 and assisted by other units, every substance could be determined automatically and rapidly integrated with the corresponding biosensor.In the experiment, the minimum detectable current of the instrument (YT2005-1) is 0.2 nA.With regard to the 1 nA which the experiment demanded,it could be up to the mustard.And the system can provide results in 180 s with a long term stability. 展开更多
关键词 point-of-care test ADUC824 weak signals HB AST and CK
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A Study of Caristi’s Fixed Point Theorem on Normed Space and Its Applications
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作者 Md. Abdul Mannan Moqbul Hossain +1 位作者 Halima Akter Samiran Mondal 《Advances in Pure Mathematics》 2021年第3期169-179,共11页
In this work, we will discuss Caristi’s fixed point theorem for mapping results introduced in the setting of normed spaces. This work is a generalization of the classical Caristi’s fixed point theorem. Also, Caristi... In this work, we will discuss Caristi’s fixed point theorem for mapping results introduced in the setting of normed spaces. This work is a generalization of the classical Caristi’s fixed point theorem. Also, Caristi’s type of fixed points theorem was partial discussed in Reich, Mizoguchi and Takahashi’s and Amini-Harandi’s results, we developed ideas that many known fixed point theorems can easily be derived from the Caristi theorem. 展开更多
关键词 NORM UNIFORMITY Mizoguchi and Takahashi’s Rich’s Problem Caristi’s Fixed point Theorem Strong and weak Contraction SEMI-CONTINUOUS
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广义混合变分不等式的weak-sharp解及算法的有限收敛
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作者 余静 夏福全 《四川师范大学学报(自然科学版)》 CAS 北大核心 2020年第5期590-596,共7页
提出广义混合变分不等式问题的解集满足的weak-sharp条件,并通过约束集的支撑函数的一些性质,获得weak-sharp条件的等价刻画.在广义混合变分不等式问题的解集满足weak-sharp条件之下,还获得任意迭代算法有限收敛的等价条件,其中有限收... 提出广义混合变分不等式问题的解集满足的weak-sharp条件,并通过约束集的支撑函数的一些性质,获得weak-sharp条件的等价刻画.在广义混合变分不等式问题的解集满足weak-sharp条件之下,还获得任意迭代算法有限收敛的等价条件,其中有限收敛指算法在有限次迭代后,得到广义混合变分不等式问题的精确解.最后,以广义混合变分不等式问题的超投影近似点算法为特例,在一定的条件下,获得该算法的有限收敛性. 展开更多
关键词 广义混合变分不等式 weak-sharp条件 有限收敛 超投影近似点算法
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Approximation of Common Fixed Points of Pointwise Asymptotic Nonexpansive Maps in a Hadamard Space
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作者 Safeer Hussain Khan H. Fukhar-ud-din 《Advances in Pure Mathematics》 2012年第6期450-456,共7页
We establish weak and strong convergence of Ishikawa type iterates of two pointwise asymptotic nonexpansive maps in a Hadamard space. For weak and strong convergence results, we drop “rate of convergence condition”,... We establish weak and strong convergence of Ishikawa type iterates of two pointwise asymptotic nonexpansive maps in a Hadamard space. For weak and strong convergence results, we drop “rate of convergence condition”, namely (Cn(x)-1)< to answer in the affirma-tive to the open question posed by Tan and Xu [1] even in a general setup. 展开更多
关键词 pointWISE ASYMPTOTIC NONEXPANSIVE Map Common Fixed point ISHIKAWA Iteration Process Strong CONVERGENCE weak CONVERGENCE
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On Almost Type α-F-Z-Weak Contraction in Metric Spaces
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作者 Jia Deng Xiaolan Liu +1 位作者 Yan Sun Laxmi Rathour 《Open Journal of Applied Sciences》 2022年第4期528-540,共13页
In this article, we introduce a new type of contraction named almost type α-F-Z-weak contraction, which comes from a combination of F-contraction, Z-contraction, and almost contraction, and then we provide sufficient... In this article, we introduce a new type of contraction named almost type α-F-Z-weak contraction, which comes from a combination of F-contraction, Z-contraction, and almost contraction, and then we provide sufficient conditions for the existence and uniqueness of fixed point of such contractions in complete metric spaces and give some related fixed point results. In addition, some related fixed point results can derive from our main results. 展开更多
关键词 Fixed point α-Admissible α-F-Z-weak Contraction Almost Contraction
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