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The 1-Lipschitz mapping between the unit spheres of two Hilbert spaces can be extended to a real linear isometry of the whole space 被引量:48
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作者 定光桂 《Science China Mathematics》 SCIE 2002年第4期479-483,共5页
Let E and F be Hilbert spaces with unit spheres S1(E) and S1(F). Suppose that V0 S1(E)→S1(F) is a Lipschitz mapping with Lipschitz constant k=1 such that -V0[S1(E)] V0[S1(E)]. Then V0 can be extended to a real linear... Let E and F be Hilbert spaces with unit spheres S1(E) and S1(F). Suppose that V0 S1(E)→S1(F) is a Lipschitz mapping with Lipschitz constant k=1 such that -V0[S1(E)] V0[S1(E)]. Then V0 can be extended to a real linear isometric mapping V from E into F. In particular, every isometric mapping from S1(E) onto S1(F) can be extended to a real linear isometric mapping from E onto F. 展开更多
关键词 ISOMETRIC mapping STRICTLY convex SMOOTH point.
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The Generalized Roper-Suffridge Extension Operator for Locally Biholomorphic Mappings 被引量:48
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作者 LIU Xiao-song,LIU Tai-shun (Department of Mathematics, University of Science and Technology of C hina, Hefei 230026, China) 《Chinese Quarterly Journal of Mathematics》 CSCD 2003年第3期221-229,共9页
In this paper, we introduce the generalized R oper-Suffridge extension operator for locally biholomorphic mappings. It is sh own that this operator preserves the starlikeness on some Reinhardt domains and does not pre... In this paper, we introduce the generalized R oper-Suffridge extension operator for locally biholomorphic mappings. It is sh own that this operator preserves the starlikeness on some Reinhardt domains and does not preserve convexity for some cases. Meanwhile, the growth theorem and di stortion theorem of the corresponding mappings are given. 展开更多
关键词 biholomorphic mappings starlike mappings and convex mappings the generalized Roper-Suffridge extension operator
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Survey of convex optimization for aerospace applications 被引量:36
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作者 Xinfu Liu Ping Lu Binfeng Pan 《Astrodynamics》 2017年第1期23-40,共18页
Convex optimization is a class of mathematical programming problems with polynomial complexity for which state-of-the-art, highly efficient numerical algorithms with predeterminable computational bounds exist. Computa... Convex optimization is a class of mathematical programming problems with polynomial complexity for which state-of-the-art, highly efficient numerical algorithms with predeterminable computational bounds exist. Computational efficiency and tractability in aerospace engineering, especially in guidance, navigation, and control (GN&C), are of paramount importance. With theoretical guarantees on solutions and computational efficiency, convex optimization lends itself as a very appealing tool. Coinciding the strong drive toward autonomous operations of aerospace vehicles, convex optimization has seen rapidly increasing utility in solving aerospace GN&C problems with the potential for onboard real-time applications. This paper attempts to provide an overview on the problems to date in aerospace guidance, path planning, and control where convex optimization has been applied. Various convexification techniques are reviewed that have been used to convexify the originally nonconvex aerospace problems. Discussions on how to ensure the validity of the convexification process are provided. Some related implementation issues will be introduced as well. 展开更多
关键词 convex optimization optimal control convexIFICATION convex relaxation
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On Decomposition Theorem of normalized biholomorphic convex mappings in Reinhardt domains 被引量:30
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作者 张文俊 刘太顺 《Science China Mathematics》 SCIE 2003年第1期94-106,共13页
The construction of normalized biholomorphic convex mappings in the Reinhardt domain $D_p = \{ (z_1 ,z_2 , \cdots ,z_n ) \in \mathbb{C}^n :\left| {z_1 } \right|^{p_1 } + \left| {z_2 } \right|^{p_2 } + \cdots + \left| ... The construction of normalized biholomorphic convex mappings in the Reinhardt domain $D_p = \{ (z_1 ,z_2 , \cdots ,z_n ) \in \mathbb{C}^n :\left| {z_1 } \right|^{p_1 } + \left| {z_2 } \right|^{p_2 } + \cdots + \left| {z_n } \right|^{p_n } < 1\} $ , p j > 2, j = 1,2,?, n) of ? n is discussed. The authors set up a Decomposition Theorem for such mappings. As a special case, it is proved that, for each such mapping f, the first k-terms of the homogeneous expansion of its j-th component f j , j = 1, 2, ?, n, depends only on z j , where k is the number that satisfies k < min {p 1, p 2,?, p n ≤ k + 1. When p1,p2, ... ,pn → ∞ , this derives the Decomposition Theorem of normalized biholomorphic convex mappings in the polydisc which was gotten by T.J. Suffridge in 1970. 展开更多
关键词 Reinhardt domain biholomorphic convex mapping Schwarz Lemma Schwarz Lemma
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高压XLPE电缆击穿的制造因素分析及有效控制 被引量:25
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作者 鲁宁 《电力工程技术》 2017年第4期43-47,58,共6页
高压电缆尤其是超高压交联聚乙烯(XLPE)电缆在输电运行中一旦被击穿,将对电网造成巨大损害,给国家造成重大损失。同时,企业在生产制造过程中,一旦发生电缆局放值(PC值)超标,甚至耐压测试击穿,给企业造成的经济损失也非常巨大。该文从电... 高压电缆尤其是超高压交联聚乙烯(XLPE)电缆在输电运行中一旦被击穿,将对电网造成巨大损害,给国家造成重大损失。同时,企业在生产制造过程中,一旦发生电缆局放值(PC值)超标,甚至耐压测试击穿,给企业造成的经济损失也非常巨大。该文从电击穿理论入手,对高压XLPE电缆的生产制造过程进行了分析研究,找出导致高压击穿及局放值超标的关键要点,如导体毛刺;导体半导电屏蔽带的电导率;模具及流道的磕碰、划伤;材料的洁净和储存;绝缘层中微孔的数量、大小、内应力等。通过对这些容易被忽视,而且又极其重要的生产制造环节进行剖析,并给出控制方法,以达到降低局放值和击穿频率,提高高压XLPE电缆整体品质的目的。 展开更多
关键词 电树枝 尖端 凸刺 击穿 局放值 微孔 晕环 焦烧
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The isometric extension problem in the unit spheres of l^p(Г)(p >1) type spaces 被引量:24
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作者 定光桂 《Science China Mathematics》 SCIE 2003年第3期333-338,共6页
In this paper, we first derive the representation theorem of onto isometric mappings in the unit spheres of l p (Г) (@#@(p >) 1,p ≠ 2 type spaces, and then we conclude that such mappings can be extended to the wh... In this paper, we first derive the representation theorem of onto isometric mappings in the unit spheres of l p (Г) (@#@(p >) 1,p ≠ 2 type spaces, and then we conclude that such mappings can be extended to the whole space as real linear isometries by using the previous result of the author. 展开更多
关键词 isometric mapping strictly convex
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A proximal point algorithm revisit on the alternating direction method of multipliers 被引量:23
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作者 CAI XingJu GU GuoYong +1 位作者 HE BingSheng YUAN XiaoMing 《Science China Mathematics》 SCIE 2013年第10期2179-2186,共8页
The alternating direction method of multipliers(ADMM)is a benchmark for solving convex programming problems with separable objective functions and linear constraints.In the literature it has been illustrated as an app... The alternating direction method of multipliers(ADMM)is a benchmark for solving convex programming problems with separable objective functions and linear constraints.In the literature it has been illustrated as an application of the proximal point algorithm(PPA)to the dual problem of the model under consideration.This paper shows that ADMM can also be regarded as an application of PPA to the primal model with a customized choice of the proximal parameter.This primal illustration of ADMM is thus complemental to its dual illustration in the literature.This PPA revisit on ADMM from the primal perspective also enables us to recover the generalized ADMM proposed by Eckstein and Bertsekas easily.A worst-case O(1/t)convergence rate in ergodic sense is established for a slight extension of Eckstein and Bertsekas’s generalized ADMM. 展开更多
关键词 alternating direction method of multipliers convergence rate convex programming proximalpoint algorithm
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Formation-Containment Control Using Dynamic Event-Triggering Mechanism for Multi-Agent Systems 被引量:21
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作者 Amir Amini Amir Asif Arash Mohammadi 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2020年第5期1235-1248,共14页
The paper proposes a novel approach for formationcontainment control based on a dynamic event-triggering mechanism for multi-agent systems.The leader-leader and follower-follower communications are reduced by utilizin... The paper proposes a novel approach for formationcontainment control based on a dynamic event-triggering mechanism for multi-agent systems.The leader-leader and follower-follower communications are reduced by utilizing the distributed dynamic event-triggered framework.We consider two separate sets of design parameters:one set comprising control and dynamic event-triggering parameters for the leaders and a second set similar to the first one with different values for the followers.The proposed algorithm includes two novel stages of codesign optimization to simultaneously compute the two sets of parameters.The design optimizations are convex and use the weighted sum approach to enable a structured trade-off between the formation-containment convergence rate and associated communications.Simulations based on non-holonomic mobile robot multi-agent systems quantify the effectiveness of the proposed approach. 展开更多
关键词 Co-design convex optimization dynamic event-triggered schemes formation-containment control multi-agent systems
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An isoperimetric deficit upper bound of the convex domain in a surface of constant curvature 被引量:17
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作者 LI Ming & ZHOU JiaZu School of Mathematics and Statistics,Southwest University,Chongqing 400715,China 《Science China Mathematics》 SCIE 2010年第8期1941-1946,共6页
In this paper,we give a reverse analog of the Bonnesen-style inequality of a convex domain in the surface X of constant curvature,that is,an isoperimetric deficit upper bound of the convex domain in X.The result is an... In this paper,we give a reverse analog of the Bonnesen-style inequality of a convex domain in the surface X of constant curvature,that is,an isoperimetric deficit upper bound of the convex domain in X.The result is an analogue of the known Bottema's result of 1933 in the Euclidean plane E2. 展开更多
关键词 KINEMATIC formula the SURFACE of constant curvature ISOPERIMETRIC DEFICIT convex set
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Recent progress in random metric theory and its applications to conditional risk measures 被引量:18
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作者 GUO TieXin 《Science China Mathematics》 SCIE 2011年第4期633-660,共28页
The purpose of this paper is to give a selective survey on recent progress in random metric theory and its applications to conditional risk measures.This paper includes eight sections.Section 1 is a longer introductio... The purpose of this paper is to give a selective survey on recent progress in random metric theory and its applications to conditional risk measures.This paper includes eight sections.Section 1 is a longer introduction,which gives a brief introduction to random metric theory,risk measures and conditional risk measures.Section 2 gives the central framework in random metric theory,topological structures,important examples,the notions of a random conjugate space and the Hahn-Banach theorems for random linear functionals.Section 3 gives several important representation theorems for random conjugate spaces.Section 4 gives characterizations for a complete random normed module to be random reflexive.Section 5 gives hyperplane separation theorems currently available in random locally convex modules.Section 6 gives the theory of random duality with respect to the locally L0-convex topology and in particular a characterization for a locally L0-convex module to be L0-pre-barreled.Section 7 gives some basic results on L0-convex analysis together with some applications to conditional risk measures.Finally,Section 8 is devoted to extensions of conditional convex risk measures,which shows that every representable L∞-type of conditional convex risk measure and every continuous Lp-type of convex conditional risk measure(1 ≤ p < +∞) can be extended to an L∞F(E)-type of σ,λ(L∞F(E),L1F(E))-lower semicontinuous conditional convex risk measure and an LpF(E)-type of T,λ-continuous conditional convex risk measure(1 ≤ p < +∞),respectively. 展开更多
关键词 random normed module random inner product module random locally convex module random conjugate space L0-convex analysis conditional risk measures
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DISTORTION THEOREMS FOR BIHOLOMORPHICCONVEX MAPPINGS ON BOUNDEDCONVEX CIRCULAR DOMAINS 被引量:19
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作者 GONGSHENG LIUTAISHUN 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1999年第3期297-304,共8页
In terms of Caratheodory metric and Kobayashi metric, distortion theorems for biholomorphic convex mappings on bounded circular convex domains are given.
关键词 Distortion theorem convex mappins Infinitesimal form of Caratheodory metric Infinitesimal form of Kobayashi-Royden metric Minkowski functional
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四叉树高效Delaunay三角网生成算法 被引量:10
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作者 石松 朱泉锋 唐丽玉 《计算机工程》 CAS CSCD 北大核心 2005年第18期87-89,共3页
实现了一种以地形为应用背景的大规模离散点快速生成TIN的算法,该算法首先对大规模离散点按一定的阈值进行四叉树分割,然后对四叉树的每个叶子块分别以凸壳技术构三角网,而后再自底向上合并具有相同父亲节点的块,最后进行全局优化,生成D... 实现了一种以地形为应用背景的大规模离散点快速生成TIN的算法,该算法首先对大规模离散点按一定的阈值进行四叉树分割,然后对四叉树的每个叶子块分别以凸壳技术构三角网,而后再自底向上合并具有相同父亲节点的块,最后进行全局优化,生成Delaunay三角网。经实际地形数据验证结果表明:同样的算法,采用四叉树分块比采用平均分块策略有着更高的执行效率。 展开更多
关键词 不规则三角网 DELAUNAY三角网 凸壳 四叉树
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SUPER EFFICIENCY IN THE NEARLY CONE-SUBCONVEXLIKE VECTOR OPTIMIZATION WITH SET-VALUED FUNCTIONS 被引量:14
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作者 徐义红 刘三阳 《Acta Mathematica Scientia》 SCIE CSCD 2005年第1期152-160,共9页
Some properties for convex cones are discussed, which are used to obtain an equivalent condition and another important property for nearly cone-subconvexlike set-valued functions. Under the nearly cone-subconvexlikene... Some properties for convex cones are discussed, which are used to obtain an equivalent condition and another important property for nearly cone-subconvexlike set-valued functions. Under the nearly cone-subconvexlikeness, some characterizations of the super efficiency are given in terms of scalarization and Lagrangian multipliers. Related results are generalized. 展开更多
关键词 Nearly cone-subconvexlikeness convex cones super efficiency SCALARIZATION Lagrangian multipliers
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BENSON PROPER EFFICIENCY IN THE NEARLY CONE-SUBCONVEXLIKE VECTOR OPTIMIZATION WITH SET-VALUED FUNCTIONS 被引量:16
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作者 XuYihong LiuSanyang 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2003年第1期95-102,共8页
Some properties of convex cones are obtained and are used to derive several equivalent conditions as well as another important property for nearly cone-subconvexlike set-valued functions. Under the assumption of nearl... Some properties of convex cones are obtained and are used to derive several equivalent conditions as well as another important property for nearly cone-subconvexlike set-valued functions. Under the assumption of nearly cone-subconvexlikeness,a Lagrangian multiplier theorem on Benson proper efficiency is presented. Related results are generalized. 展开更多
关键词 nearly cone-subconvexlikeness convex cones Benson proper efficiency Lagrangian multiplier theorem.
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The Bonnesen isoperimetric inequality in a surface of constant curvature 被引量:18
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作者 ZENG ChunNa MA Lei +1 位作者 ZHOU JiaZu CHEN FangWeit 《Science China Mathematics》 SCIE 2012年第9期1913-1919,共7页
We first estimate the containment measure of a convex domain to contain in another in a surface X of constant curvature.Then we obtain the analogue of the known Bonnesen isoperimetric inequality for convex domain in X... We first estimate the containment measure of a convex domain to contain in another in a surface X of constant curvature.Then we obtain the analogue of the known Bonnesen isoperimetric inequality for convex domain in X.Finally we strengthen the known Bonnesen isoperimetric inequality. 展开更多
关键词 hyperbolic plane projective plane kinematic formula Bonnesen isoperimetric inequality isoperi-metric deficit convex domain
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THE SCHUR HARMONIC CONVEXITY FOR A CLASS OF SYMMETRIC FUNCTIONS 被引量:13
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作者 褚玉明 孙天川 《Acta Mathematica Scientia》 SCIE CSCD 2010年第5期1501-1506,共6页
In this article, we prove that the symmetric function Fn(x,r)=∑i1+i2+……in=r(x1(i1x2^i2……xn^in)1/r is Schur harmonic convex for x ∈ R+n and r ∈N -=(1, 2, 3,...} As its applications, some analytic inequa... In this article, we prove that the symmetric function Fn(x,r)=∑i1+i2+……in=r(x1(i1x2^i2……xn^in)1/r is Schur harmonic convex for x ∈ R+n and r ∈N -=(1, 2, 3,...} As its applications, some analytic inequalities are established. 展开更多
关键词 symmetric function Schur convex Schur harmonic convex
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Growth theorem of convex mappings on bounded convex circular domains 被引量:13
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作者 刘太顺 任广斌 《Science China Mathematics》 SCIE 1998年第2期123-130,共8页
The growth theorem and the 1/2 covering theorem are obtained for the class of normalized biholomorphic convex mappings on bounded convex circular domains, which extend the corresponding results of Sufridge, Thomas, Li... The growth theorem and the 1/2 covering theorem are obtained for the class of normalized biholomorphic convex mappings on bounded convex circular domains, which extend the corresponding results of Sufridge, Thomas, Liu, Gong, Yu, and Wang. The approach is new, which does not appeal to the automorphisms of the domains; and the domains discussed are rather general on which convex mappings can be studied, since the domain may not have a convex mapping if it is not convex. 展开更多
关键词 convex MAPPINGS growth and COVERING theorem convex CIRCULAR domains.
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A novel image segmentation approach for wood plate surface defect classification through convex optimization 被引量:15
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作者 Zhanyuan Chang Jun Cao Yizhuo Zhang 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第6期1789-1795,共7页
Detection of wood plate surface defects using image processing is a complicated problem in the forest industry as the image of the wood surface contains different kinds of defects. In order to obtain complete defect i... Detection of wood plate surface defects using image processing is a complicated problem in the forest industry as the image of the wood surface contains different kinds of defects. In order to obtain complete defect images, we used convex optimization(CO) with different weights as a pretreatment method for smoothing and the Otsu segmentation method to obtain the target defect area images. Structural similarity(SSIM) results between original image and defect image were calculated to evaluate the performance of segmentation with different convex optimization weights. The geometric and intensity features of defects were extracted before constructing a classification and regression tree(CART) classifier. The average accuracy of the classifier is 94.1% with four types of defects on Xylosma congestum wood plate surface: pinhole, crack,live knot and dead knot. Experimental results showed that CO can save the edge of target defects maximally, SSIM can select the appropriate weight for CO, and the CART classifier appears to have the advantages of good adaptability and high classification accuracy. 展开更多
关键词 convex optimization Threshold segmentation Structure similarity Decision tree Defect recognition
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New approaches to robust l2-l∞ and H∞ filtering for uncertain discrete-time systems 被引量:11
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作者 高会军 王常虹 《Science in China(Series F)》 2003年第5期355-370,共16页
The problems of robust I2-I∞ and H∞ filtering for discrete-time systems with parameter uncertainty residing in a polytope are investigated in this paper. The filtering strategies are based on new robust performance ... The problems of robust I2-I∞ and H∞ filtering for discrete-time systems with parameter uncertainty residing in a polytope are investigated in this paper. The filtering strategies are based on new robust performance criteria derived from a new result of parameter-dependent Lyapunov stability condition, which exhibit less conservativeness than previous results in the quadratic framework. The designed filters guaranteeing a prescribed I2-I∞ or H∞ noise attenuation level can be obtained from the solution of convex optimization problems, which can be solved via efficient interior point methods. Numerical examples have shown that the filter design procedures proposed in this paper are much less conservative than earlier results. 展开更多
关键词 robust filtering state estimation linear matrix inequality convex optimization I2-I∞ performance H∞ performance.
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Existence,uniqueness and stability of C^m solutions of iterative functional equations 被引量:14
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作者 麦结华 刘新和 《Science China Mathematics》 SCIE 2000年第9期897-913,共17页
In this paper we discuss a relatively general kind of iterative functional equation G(x,f(x), ...,f n (x)) = 0 (for allx ∈J), whereJ is a connected closed subset of the real number axis ?,G∈C m (J n+1, ?) andn ≥ 2.... In this paper we discuss a relatively general kind of iterative functional equation G(x,f(x), ...,f n (x)) = 0 (for allx ∈J), whereJ is a connected closed subset of the real number axis ?,G∈C m (J n+1, ?) andn ≥ 2. Using the method of approximating fixed points by small shift of maps, choosing suitable metrics on functional spaces and finding a relation between uniqueness and stability of fixed points of maps of general spaces, we prove the existence, uniqueness and stability ofCm solutions of the above equation for any integer m ≥ 0 under relatively weak conditions, and generalize related results in reference in different aspects. 展开更多
关键词 iterative functional equation C m map function space compact convex set flxed point diagonal method
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