期刊文献+
共找到257篇文章
< 1 2 13 >
每页显示 20 50 100
Fixed-Point Iteration Method for Solving the Convex Quadratic Programming with Mixed Constraints 被引量:1
1
作者 Ruopeng Wang Hong Shi +1 位作者 Kai Ruan Xiangyu Gao 《Applied Mathematics》 2014年第2期256-262,共7页
The present paper is devoted to a novel smoothing function method for convex quadratic programming problem with mixed constrains, which has important application in mechanics and engineering science. The problem is re... The present paper is devoted to a novel smoothing function method for convex quadratic programming problem with mixed constrains, which has important application in mechanics and engineering science. The problem is reformulated as a system of non-smooth equations, and then a smoothing function for the system of non-smooth equations is proposed. The condition of convergences of this iteration algorithm is given. Theory analysis and primary numerical results illustrate that this method is feasible and effective. 展开更多
关键词 fixed-point ITERATION CONVEX QUADRATIC programming Problem Convergence SMOOTHING Function
下载PDF
Compactness, Contractibility and Fixed Point Properties of the Pareto Sets in Multi-Objective Programming
2
作者 Zdravko Dimitrov Slavov Christina Slavova Evans 《Applied Mathematics》 2011年第5期556-561,共6页
This paper presents the Pareto solutions in continuous multi-objective mathematical programming. We discuss the role of some assumptions on the objective functions and feasible domain, the relationship between them, a... This paper presents the Pareto solutions in continuous multi-objective mathematical programming. We discuss the role of some assumptions on the objective functions and feasible domain, the relationship between them, and compactness, contractibility and fixed point properties of the Pareto sets. The authors have tried to remove the concavity assumptions on the objective functions which are usually used in multi-objective maximization problems. The results are based on constructing a retraction from the feasible domain onto the Pareto-optimal set. 展开更多
关键词 Multi-Objective programming PARETO-OPTIMAL Pareto-Front Compact CONTRACTIBLE fixed point RETRACTION
下载PDF
Hierarchical adaptive stereo matching algorithm for obstacle detection with dynamic programming 被引量:1
3
作者 Ming BAI Yan ZHUANG Wei WANG 《控制理论与应用(英文版)》 EI 2009年第1期41-47,共7页
An adaptive weighted stereo matching algorithm with multilevel and bidirectional dynamic programming based on ground control points (GCPs) is presented. To decrease time complexity without losing matching precision,... An adaptive weighted stereo matching algorithm with multilevel and bidirectional dynamic programming based on ground control points (GCPs) is presented. To decrease time complexity without losing matching precision, using a multilevel search scheme, the coarse matching is processed in typical disparity space image, while the fine matching is processed in disparity-offset space image. In the upper level, GCPs are obtained by enhanced volumetric iterative algorithm enforcing the mutual constraint and the threshold constraint. Under the supervision of the highly reliable GCPs, bidirectional dynamic programming framework is employed to solve the inconsistency in the optimization path. In the lower level, to reduce running time, disparity-offset space is proposed to efficiently achieve the dense disparity image. In addition, an adaptive dual support-weight strategy is presented to aggregate matching cost, which considers photometric and geometric information. Further, post-processing algorithm can ameliorate disparity results in areas with depth discontinuities and related by occlusions using dual threshold algorithm, where missing stereo information is substituted from surrounding regions. To demonstrate the effectiveness of the algorithm, we present the two groups of experimental results for four widely used standard stereo data sets, including discussion on performance and comparison with other methods, which show that the algorithm has not only a fast speed, but also significantly improves the efficiency of holistic optimization. 展开更多
关键词 Stereo matching Ground control points Adaptive weighted aggregation Bidirectional dynamic programming Obstacle detection based on stereo vision
下载PDF
Shape Retrieval Using ECPDH with Dynamic Programming
4
作者 Xin Shu Lei Pan Yunsong Qi 《Journal of Computer and Communications》 2016年第16期63-78,共16页
The matching and retrieval of the 2D shapes are challenging issues in object recognition and computer vision. In this paper, we propose a new object contour descriptor termed ECPDH (Elliptic Contour Points Distributio... The matching and retrieval of the 2D shapes are challenging issues in object recognition and computer vision. In this paper, we propose a new object contour descriptor termed ECPDH (Elliptic Contour Points Distribution Histogram), which is based on the distribution of the points on an object contour under the polar coordinates. ECPDH has the essential merits of invariance to scale and translation. Dynamic Programming (DP) algorithm is used to measure the distance between the ECPDHs. The effectiveness of the proposed method is demonstrated using some standard tests on MPEG-7 shape database. The results show the precision and recall of our method over other recent methods in the literature. 展开更多
关键词 Shape Descriptor Shape Retrieval Elliptic Contour points Distribution Histogram dynamic programming
下载PDF
A NEW DETERMINISTIC FORMULATION FOR DYNAMIC STOCHASTIC PROGRAMMING PROBLEMS AND ITS NUMERICAL COMPARISON WITH OTHERS
5
作者 陈志平 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 2003年第2期173-185,共13页
A new deterministic formulation,called the conditional expectation formulation,is proposed for dynamic stochastic programming problems in order to overcome some disadvantages of existing deterministic formulations.We ... A new deterministic formulation,called the conditional expectation formulation,is proposed for dynamic stochastic programming problems in order to overcome some disadvantages of existing deterministic formulations.We then check the impact of the new deterministic formulation and other two deterministic formulations on the corresponding problem size,nonzero elements and solution time by solving some typical dynamic stochastic programming problems with different interior point algorithms.Numerical results show the advantage and application of the new deterministic formulation. 展开更多
关键词 动态随机规划 条件期望公式 内点算法 随机事件
下载PDF
Uncertainty Principle and Bifurcations in the SU(2) Nonlinear Semiquantum Dynamics
6
作者 Roberta Hansen Claudia M. Sarris Angelo Plastino 《Applied Mathematics》 2018年第1期1-16,共16页
In this paper, a nonlinear semiquantum Hamiltonian associated to the special unitary group SU(2) Lie algebra is studied so as to analyze its dynamics. The treatment here applied allows for a reduction in: 1) the syste... In this paper, a nonlinear semiquantum Hamiltonian associated to the special unitary group SU(2) Lie algebra is studied so as to analyze its dynamics. The treatment here applied allows for a reduction in: 1) the system’s dimension, as well as 2) the number of system’s parameters (to only three). We can now discern clear patterns in: 1) the complete characterization of the system’s fixed points and 2) their stability. It is shown that the parameter associated to the uncertainty principle, which constitutes a very strong constraint, is the key one in determining the presence of fixed points and bifurcation curves in the parameter’s space. 展开更多
关键词 Semiquantum dynamics Uncertainty PRINCIPLE fixed pointS BIFURCATION CURVES
下载PDF
Existence of Traveling Waves in Lattice Dynamical Systems
7
作者 Xiaojun Li Yong Jiang Ziming Du 《Journal of Applied Mathematics and Physics》 2016年第7期1231-1236,共6页
Existence of traveling wave solutions for some lattice differential equations is investigated. We prove that there exists  c<sub>*</sub>>0 such that for each c≥c*</sub>, the systems und... Existence of traveling wave solutions for some lattice differential equations is investigated. We prove that there exists  c<sub>*</sub>>0 such that for each c≥c*</sub>, the systems under consideration admit monotonic nondecreasing traveling waves. 展开更多
关键词 Traveling Wave Lattice dynamical Systems Schauder’s fixed point Theorem
下载PDF
Existence and Uniqueness of Solutions for two Classes of Functional Equations Arising in Dynamic Programming 被引量:1
8
作者 Ze-qing Liu Shin Min Kang 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 2007年第2期195-208,共14页
In this paper we establish the existence, uniqueness and iterative approximation of solutions for two classes of functional equations arising in dynamic programming of multistage decision processes. The results presen... In this paper we establish the existence, uniqueness and iterative approximation of solutions for two classes of functional equations arising in dynamic programming of multistage decision processes. The results presented here extend, and unify the corresponding results due to Bellman, Bhakta and Choudhury, Bhakta and Mitra, Liu and others. 展开更多
关键词 Functional equation dynamic programming fixed point successive approximation nonexpansive mapping
原文传递
双转子转速协同规划的涡扇发动机加减速控制计划研究
9
作者 强星煜 周登极 +1 位作者 尉询楷 王浩 《推进技术》 EI CAS CSCD 北大核心 2024年第4期233-242,共10页
当前涡扇发动机加减速控制计划,不能规划双轴加速进程,导致加速末期推力波动。本文提出了分阶段的加速度控制计划,按边界约束划分加速进程,基于动态稳定法设计初始加速度计划,通过寻找系统参数的超调临界点,协同修正初始加速度计划,满... 当前涡扇发动机加减速控制计划,不能规划双轴加速进程,导致加速末期推力波动。本文提出了分阶段的加速度控制计划,按边界约束划分加速进程,基于动态稳定法设计初始加速度计划,通过寻找系统参数的超调临界点,协同修正初始加速度计划,满足边界约束的同时保证双转子加速时间相同。在仿真验证环节,与基于定状态法的控制计划比较,本文方法可避免燃油振荡现象,推力超调量降低2.43%,推力稳定时间缩短1.045 s;与等转速增量的加速度控制计划比较,进一步改进了本文方法,推力响应时间缩短0.24 s,控制计划设计耗时为7.5781 s。综上,本文方法缩短了推力超调量和推力稳定时间,有望应用于发动机控制计划在线计算。 展开更多
关键词 涡扇发动机 分阶段控制计划 加速进程划分 动态稳定法 超调临界点
下载PDF
有向根树上局部更新函数为NAND或NOR的广义并序动力系统的固定点
10
作者 孙彦文 郑洁 《Journal of Donghua University(English Edition)》 CAS 2024年第2期214-220,共7页
研究对象为有向根树上的广义并序动力系统,其局部更新函数为NAND或NOR。为了研究这类广义并序动力系统中的固定点的个数及状态,采用结构分析法和分类讨论法,得到了此类动力系统中关于固定点的确切结果。证明了这类广义并序动力系统中的... 研究对象为有向根树上的广义并序动力系统,其局部更新函数为NAND或NOR。为了研究这类广义并序动力系统中的固定点的个数及状态,采用结构分析法和分类讨论法,得到了此类动力系统中关于固定点的确切结果。证明了这类广义并序动力系统中的固定点状态完全由有向根树中的自环决定。离散动力系统是数学建模的重要工具,该文可为离散动力系统的研究提供新的思路。 展开更多
关键词 广义并序动力系统 有向根树 布尔函数 固定点
下载PDF
Dynamics of 2×2 matrix non-Hermitian quantum systems on Bloch sphere
11
作者 Libin Fu 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第4期66-71,共6页
By casting evolution to the Bloch sphere, the dynamics of 2 × 2 matrix non-Hermitian systems are investigated in detail. This investigation reveals that there are four kinds of dynamical modes for such systems. T... By casting evolution to the Bloch sphere, the dynamics of 2 × 2 matrix non-Hermitian systems are investigated in detail. This investigation reveals that there are four kinds of dynamical modes for such systems. The different modes are classified by different kinds of fixed points, namely,the elliptic point, spiral point, critical node, and degenerate point. The Hermitian systems and the unbroken PT non-Hermitian cases belong to the category with elliptic points. The degenerate point just corresponds to the systems with exceptional point(EP). The topological properties of the fixed point are also discussed. It is interesting that the topological charge for the degenerate point is two, while the others are one. 展开更多
关键词 non-Hermitian quantum system two-level system dynamics on the Bloch sphere PT-SYMMETRY fixed points
原文传递
基于动态规划的逐点后退法在路线压缩中的应用研究
12
作者 李岩 王佳豪 王利民 《河北建筑工程学院学报》 CAS 2024年第1期238-243,共6页
提出了一种路线数据压缩算法,该算法以“道格拉斯-普克(Douglas-Peucker, DP)压缩算法”为基础,并对其进行了一系列的改进。该算法对路线中的矢量坐标,以所设定的阈值为参考标准,从后向前递归的进行压缩,并提取出特征点。相对于DP算法,... 提出了一种路线数据压缩算法,该算法以“道格拉斯-普克(Douglas-Peucker, DP)压缩算法”为基础,并对其进行了一系列的改进。该算法对路线中的矢量坐标,以所设定的阈值为参考标准,从后向前递归的进行压缩,并提取出特征点。相对于DP算法,本算法具有更高的压缩效率,更小的压缩误差,在相对复杂曲线的压缩上,本算法在准确度方面具有更优异的表现。通过进一步结合动态规划方法,可使该算法平均误差在原算法的基础上再降低70%的误差,从而保证了压缩后曲线的准确度和完整性。 展开更多
关键词 曲线压缩 DP算法 动态规划算法 特征点
下载PDF
Multiplicities of fixed points of holomorphic maps in several complex variables 被引量:1
13
作者 张广远 《Science China Mathematics》 SCIE 2001年第3期330-337,共8页
Let Δυ be the unit ball in ?υ with center 0 (the origin of υ) and let F:Δυ→?υbe a holomorphic map withF(0) = 0. This paper is to study the fixed point multiplicities at the origin 0 of the iteratesF i =F°... Let Δυ be the unit ball in ?υ with center 0 (the origin of υ) and let F:Δυ→?υbe a holomorphic map withF(0) = 0. This paper is to study the fixed point multiplicities at the origin 0 of the iteratesF i =F°?°F (i times),i = 1,2,.... This problem is easy when υ = 1, but it is very complicated when υ > 1. We will study this problem generally. 展开更多
关键词 holomorphic maps complex dynamical systems multiplicities of fixed points
原文传递
基于水下目标抓取的UVMS抗扰控制方法研究
14
作者 魏延辉 赵康康 谢吉顺 《中北大学学报(自然科学版)》 CAS 2024年第2期132-145,共14页
水下机器人-机械臂系统(UVMS)在水下作业过程中存在自身结构不确定性干扰、系统动力学耦合干扰以及海流干扰的问题,这对水下机器人的运动控制提出了更高的要求。本文以某欠驱动水下机器人系统作为研究对象,提出了一种误差受限的抗干扰... 水下机器人-机械臂系统(UVMS)在水下作业过程中存在自身结构不确定性干扰、系统动力学耦合干扰以及海流干扰的问题,这对水下机器人的运动控制提出了更高的要求。本文以某欠驱动水下机器人系统作为研究对象,提出了一种误差受限的抗干扰控制方法。基于视线法和设定性能函数得到UVMS的误差动力学模型,再基于此模型设计水下机器人(AUV)抗扰控制器。通过牛顿-欧拉方程估算机械臂对于AUV本体的耦合干扰并进行实时补偿。采用神经网络控制补偿AUV系统的结构性不确定性,并利用自适应控制来补偿神经网络估计误差、非结构性不确定性误差和机械臂耦合干扰的补偿误差。通过机械臂静止和定点作业两组工况下的仿真实验发现,运动控制任务符合设定预期时间和跟踪精度,同时也验证了分离式UVMS运动控制方案在水下定点作业任务中的可行性和有效性。本文方法具有很强的鲁棒性,且能够通过此抗扰控制方法来抑制这些不确定性干扰的影响。 展开更多
关键词 UVMS 抗扰控制器 水下定点作业 误差动力学方程
下载PDF
多智能体系统事件触发固定时间最优一致性
15
作者 甘勤涛 李瑞鸿 茹怡珊 《陆军工程大学学报》 2024年第2期28-38,共11页
针对多智能体系统(multi-agent systems,MASs)固定时间最优领导-跟随一致性问题,基于性能优化目标,设计了一种基于事件触发机制的最优控制策略,兼顾固定时间最优一致性控制目标和有限的系统通信计算资源。为了近似求解Hamilton-Jacobi-B... 针对多智能体系统(multi-agent systems,MASs)固定时间最优领导-跟随一致性问题,基于性能优化目标,设计了一种基于事件触发机制的最优控制策略,兼顾固定时间最优一致性控制目标和有限的系统通信计算资源。为了近似求解Hamilton-Jacobi-Bellman(HJB)方程获得最优值函数的表达式,提出一种仅包含Critic神经网络结构的自适应动态规划(adaptive dynamic programming,ADP)在线学习算法,结合梯度下降法和经验重放方法,利用历史记录数据和当前数据更新神经网络权重向量近似最优值函数及其梯度。采用基于无人地面车辆的无人集群系统验证了该方法的可行性。 展开更多
关键词 多智能体系统 最优控制 固定时间一致性 自适应动态规划 事件触发机制
下载PDF
The numbers of periodic orbits hidden at fixed points of 2-dimensional holomorphic mappings
16
作者 ZHANG GuangYuan Department of Mathematical Sciences, Tsinghua University, Beijing 100084, China 《Science China Mathematics》 SCIE 2010年第3期863-886,共24页
Let △n be the ball |x| 【 1 in the complex vector space C n , let f :△n→ C n be a holomorphic mapping and let M be a positive integer. Assume that the origin 0 = (0, . . . , 0) is an isolated fixed point of both f ... Let △n be the ball |x| 【 1 in the complex vector space C n , let f :△n→ C n be a holomorphic mapping and let M be a positive integer. Assume that the origin 0 = (0, . . . , 0) is an isolated fixed point of both f and the M-th iteration f M of f. Then the (local) Dold index P M (f, 0) at the origin is well defined, which can be interpreted to be the number of virtual periodic points of period M of f hidden at the origin: any holomorphic mapping f 1 :△n→ C n sufficiently close to f has exactly P M (f, 0) distinct periodic points of period M near the origin, provided that all the fixed points of f M 1 near the origin are simple. Therefore, the number O M (f, 0) = P M (f, 0)/M can be understood to be the number of virtual periodic orbits of period M hidden at the fixed point. According to the works of Shub-Sullivan and Chow-Mallet-Paret-Yorke, a necessary condition so that there exists at least one virtual periodic orbit of period M hidden at the fixed point, i.e., O M (f, 0)≥1, is that the linear part of f at the origin has a periodic point of period M. It is proved by the author recently that the converse holds true. In this paper, we will study the condition for the linear part of f at 0 so that O M (f, 0)≥2. For a 2 × 2 matrix A that is arbitrarily given, the goal of this paper is to give a necessary and sufficient condition for A, such that O M (f, 0)≥2 for all holomorphic mappings f :△2 → C 2 such that f(0) = 0, Df(0) = A and that the origin 0 is an isolated fixed point of f M . 展开更多
关键词 complex dynamicAL systems periodic pointS fixed point indices
原文传递
分析老年慢性心力衰竭患者窦性心率震荡检查的效果
17
作者 云斐 刘艺 蒋柳溪 《中外医疗》 2024年第15期32-35,共4页
目的 研究窦性心率震荡运用于老年慢性心力衰竭患者中的效果。方法 方便选取新疆生产建设兵团第七师医院于2022年3月—2024年3月收治的55例老年慢性心力衰竭患者和30例健康体检者为研究对象。老年慢性心力衰竭患者为观察组、健康体检者... 目的 研究窦性心率震荡运用于老年慢性心力衰竭患者中的效果。方法 方便选取新疆生产建设兵团第七师医院于2022年3月—2024年3月收治的55例老年慢性心力衰竭患者和30例健康体检者为研究对象。老年慢性心力衰竭患者为观察组、健康体检者为对照组,两组均行24 h窦性心率震荡检查,计算窦性心率震荡的相关数据,分析窦性心率震荡检查用于老年慢性心力衰竭患者的效果。结果 患者心功能分级越高,震荡初始值、左心室舒张末期内径、左心室收缩末期内径、左心室舒张末期容积、左心室收缩末期容积越高,而震荡斜率值、左室射血分数越低,差异有统计学意义(P均<0.05)。观察组震荡初始值(0.48±0.11)%高于对照组,震荡斜率值(2.16±0.22)ms/RR低于对照组,差异有统计学意义(t=5.430、22.355,P均<0.05)。结论 窦性心率震荡提示在老年慢性心力衰竭患者不同心功能下有明显的差异,可为其治疗和预后提供依据。 展开更多
关键词 窦性心率震荡 老年慢性心力衰竭 超声心动图 24 h动态定点图
下载PDF
EXISTENCE OF POSITIVE SOLUTIONS TO A THREE-POINT BOUNDARY VALUE PROBLEM FOR SECOND ORDER DYNAMIC EQUATIONS WITH DERIVATIVE ON TIME SCALES
18
作者 Jinjun Fan Fangfang Han 《Annals of Differential Equations》 2014年第3期282-290,共9页
In this paper, we consider the existence of positive solutions to a three-point boundary value problem for second order dynamic equations with derivative on time scales.Applying Leggett-Williams fixed point theorem, w... In this paper, we consider the existence of positive solutions to a three-point boundary value problem for second order dynamic equations with derivative on time scales.Applying Leggett-Williams fixed point theorem, we obtain at least three positive solutions to the problem. An example is also presented to illustrate the applications of the results obtained. 展开更多
关键词 positive solutions time scales dynamic equations fixed point theorem
原文传递
非线性动力系统多重周期解的伪不动点追踪法 被引量:17
19
作者 刘恒 虞烈 +2 位作者 谢友柏 刘恭忍 姚福生 《力学学报》 EI CSCD 北大核心 1999年第2期222-229,共8页
提出一种求解非线性动力系统多重周期解的新的思路和方法(伪不动点追踪法);这一方法由寻找非线性动力系统同时存在的各个周期解间的联系入手;引入一个反映系统全局瞬态信息的标量函数,将非线性动力系统求各个周期解的问题转化为此... 提出一种求解非线性动力系统多重周期解的新的思路和方法(伪不动点追踪法);这一方法由寻找非线性动力系统同时存在的各个周期解间的联系入手;引入一个反映系统全局瞬态信息的标量函数,将非线性动力系统求各个周期解的问题转化为此标量函数的寻优问题.文中以布鲁塞尔振子及轴承转子系统为例。顺序求得了T,3T,4T,…周期解。 展开更多
关键词 非线性 动力系统 周期解 不动点追踪
下载PDF
计及可平移负荷的微网经济优化调度 被引量:75
20
作者 符杨 蒋一鎏 +1 位作者 李振坤 卫春峰 《中国电机工程学报》 EI CSCD 北大核心 2014年第16期2612-2620,共9页
微网以一种更为有效的方式集成了分布式能源、储能设备和可控负荷。经济调度是微网经济运行的关键,该文从供能和负荷控制角度对微网经济优化调度问题进行研究。综合考虑不同用电特性的可平移负荷单元,建立可平移负荷模型,并提出负荷平... 微网以一种更为有效的方式集成了分布式能源、储能设备和可控负荷。经济调度是微网经济运行的关键,该文从供能和负荷控制角度对微网经济优化调度问题进行研究。综合考虑不同用电特性的可平移负荷单元,建立可平移负荷模型,并提出负荷平移求解策略。将经济调度视为离散最优控制问题,构建基于动态规划的微网经济优化调度模型。然后将其转化为二次规划问题,采用预估校正内点算法求解。算例分析了负荷平移对调度结果的影响,从而验证了所提模型和算法的有效性。 展开更多
关键词 微网 可平移负荷 经济调度 动态规划 二次规划 预估校正内点算法
下载PDF
上一页 1 2 13 下一页 到第
使用帮助 返回顶部