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基于准多项式的二阶时滞系统的稳定性分析
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作者 陈宇杰 《浙江理工大学学报(自然科学版)》 2006年第1期68-71,共4页
从频域分析一类二阶时滞系统的稳定性。运用时延微分方程领域的两个结论对特征方程转化而来的准多项式进行稳定性分析,给出了使系统稳定的控制器参数范围。
关键词 二阶时滞系统 准多项式 稳定性
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有限域上的广义准多项式码
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作者 刘丽 徐溢 《系统科学与数学》 CSCD 北大核心 2019年第3期470-476,共7页
文章提出了一类新的码--广义准多项式码,它是多项式码的一种推广.文中首先给出了广义准多项式码的概念及其生成矩阵的结构,然后重点研究了1-生成元的广义准多项式码参数的相关性质,并且基于这些性质构造出了一些最优码.
关键词 多项式 广义准多项式 1-生成元 最优码
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多项式展开配准的多图谱大脑磁共振图像分割 被引量:2
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作者 蔡文琴 王远军 《光学技术》 CAS CSCD 北大核心 2020年第6期734-740,共7页
全脑区的自动分割对于大脑疾病的诊断和治疗具有重要的临床意义。为了提高分割准确率,提出了一种多项式展开配准的多图谱分割算法。利用线性多项式展开模型,结合仿射变换和非刚体变换将待分割的目标图像与图谱图像进行逐一的配准来获取... 全脑区的自动分割对于大脑疾病的诊断和治疗具有重要的临床意义。为了提高分割准确率,提出了一种多项式展开配准的多图谱分割算法。利用线性多项式展开模型,结合仿射变换和非刚体变换将待分割的目标图像与图谱图像进行逐一的配准来获取位移场;利用归一化互信息计算二者的相似度,筛选出与目标图像相似度较高的图谱,并对图谱的标记图像进行位移场映射,得到粗分割结果;采用全局加权投票法将粗分割结果进行融合,得到最终的细分割结果。选取了35例来自MICCAI 2012 Multi-Atlas Labeling挑战和10例来自上海交通大学医学院附属第九人民医院的磁共振T1加权图像对该方法进行验证,最终全脑区的DSC值分别为0.7585和0.7351。实验结果表明,算法具有较高的大脑分割精确度和鲁棒性,有望辅助临床进行大脑相关疾病的诊断和治疗。 展开更多
关键词 磁共振成像 多图谱分割 全脑区 多项式展开配
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二阶加纯滞后过程的非脆弱PID稳定化控制器设计 被引量:5
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作者 徐建明 俞立 杨马英 《控制与决策》 EI CSCD 北大核心 2003年第1期29-33,39,共6页
根据 Herm ite- Biehler定理在准多项式稳定性问题上的推广 ,研究用 PID控制器镇定二阶加纯滞后过程的问题。给出了使闭环系统稳定的 PID参数区域 ,并以稳定的 PID参数区域内切圆半径为目标函数 ,寻优得到非脆弱 PID控制器参数。最后通... 根据 Herm ite- Biehler定理在准多项式稳定性问题上的推广 ,研究用 PID控制器镇定二阶加纯滞后过程的问题。给出了使闭环系统稳定的 PID参数区域 ,并以稳定的 PID参数区域内切圆半径为目标函数 ,寻优得到非脆弱 PID控制器参数。最后通过线性规划给出了非脆弱 PID稳定化控制器的设计方法。 展开更多
关键词 二阶加纯滞后过程 非脆弱PID稳定化控制器 设计 PID控制 线性规划 准多项式 工业控制 Hermite-Biehler定理
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大口径SiC轻量化主镜热变形的定标 被引量:25
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作者 吴小霞 王鸣浩 +1 位作者 明名 王富国 《光学精密工程》 EI CAS CSCD 北大核心 2012年第6期1243-1249,共7页
为了准确地预算出大口径SiC轻量化主镜镜面的温度变形,研究了不同热模式下SiC轻量化主镜镜面面形的定标和计算方法。将SiC轻量化主镜上的温度传感器在轴向厚度方向上进行分层处理,对每层上的温度分布采用准Zernike多项式进行拟合。以4m... 为了准确地预算出大口径SiC轻量化主镜镜面的温度变形,研究了不同热模式下SiC轻量化主镜镜面面形的定标和计算方法。将SiC轻量化主镜上的温度传感器在轴向厚度方向上进行分层处理,对每层上的温度分布采用准Zernike多项式进行拟合。以4mSiC轻量化主镜为例,采用有限元法分别对准Zernike前9项温度模式(18种温度场)下的镜面变形进行定标计算,得出各种单位载荷作用下轻量化主镜镜面的最大变形以及面形误差PV值和RMS值。计算结果表明:准Zernike第一项模式、单位载荷作用下镜面变形最大,其面形误差RMS为278.3nm。采用最小二乘法对各种温差场下的镜面误差进行准Zernike多项式拟合,获得了准Zernike像差项的系数。采用最小二乘法拟合计算出镜面变形误差产生的准Zernike像差项的系数,结果表明,18种温度场下产生的像差形式主要有:平移、倾斜、离焦、彗差和像散。 展开更多
关键词 大口径主镜 SiC轻量化主镜 热变形 定标 Zernike多项式
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主动光学技术在薄镜面中的应用及算法研究 被引量:5
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作者 王富国 杨洪波 +1 位作者 李宏壮 杨飞 《红外技术》 CSCD 北大核心 2007年第12期704-707,共4页
针对采用准zernike多项式拟和法求主动光学校正力的过程中,因为准zernike多项式的不正交性造成求解误差大、求解不稳定的问题,提出了对准zernike多项式进行householder变换的方法。该方法不同于传统的最小二乘法和Gram-Schmidt正交化方... 针对采用准zernike多项式拟和法求主动光学校正力的过程中,因为准zernike多项式的不正交性造成求解误差大、求解不稳定的问题,提出了对准zernike多项式进行householder变换的方法。该方法不同于传统的最小二乘法和Gram-Schmidt正交化方法,它避免了因构造法方程组出现严重病态而引入的计算误差。根据该方法求出主镜的刚度矩阵,然后采用阻尼最小二乘法求校正力。基于此方法对直径为400 mm的实验镜进行了多次仿真计算,计算结果表明,采用householder变换后波面拟和精确,求解稳定,校正效果较好。 展开更多
关键词 主动光学 householder变换 zernike多项式
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F_2+uF_2上奇偶长循环码的结构特性
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作者 盖新貌 李超 《计算机工程与科学》 CSCD 2007年第7期74-76,共3页
码长为2n(n为奇数)的循环码被称为奇偶长的循环码。本文证明了F2+uF2上奇偶长循环码具有形如(a1(x2)a3(x2)a4(x2)a5(x)a6(x),ua1(x2)a2(x2)a4(x)a5(x2))的结构,其中ai(x),i=1,2,…,6,满足■6i=1ai(x)=xn-1,而且a5(x)≡a5(x)(modu),并给... 码长为2n(n为奇数)的循环码被称为奇偶长的循环码。本文证明了F2+uF2上奇偶长循环码具有形如(a1(x2)a3(x2)a4(x2)a5(x)a6(x),ua1(x2)a2(x2)a4(x)a5(x2))的结构,其中ai(x),i=1,2,…,6,满足■6i=1ai(x)=xn-1,而且a5(x)≡a5(x)(modu),并给出了奇偶长循环码之对偶码的生成元表达。 展开更多
关键词 F2+uF2 循环码 生成元 多项式
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Strategies for h-Adaptive Refinement for a Finite Element Treatment of Harmonic Oscillator Schrodinger Eigenproblem
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作者 T.D.Young R.Armiento 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第6期1017-1023,共7页
A Schrodinger eigenvalue problem is solved for the 219 quantum simple harmonic oscillator using a finite element discretization of real space within which elements are adaptively spatially refined. We compare two comp... A Schrodinger eigenvalue problem is solved for the 219 quantum simple harmonic oscillator using a finite element discretization of real space within which elements are adaptively spatially refined. We compare two competing methods of adaptively discretizing the real-space grid on which computations are performed without modifying the standard polynomial basis-set traditionally used in finite element interpolations; namely, (i) an application of the Kelly error estimator, and (ii) a refinement based on the local potential level. When the performance of these methods are compared to standard uniform global refinement, we find that they significantly improve the total time spent in the eigensolver. 展开更多
关键词 adaptive finite element analysis Harmonic oscillator problems Schrodinger equation
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SEED REGION SELECTION AND HOMOGENEITY CRITERION FOR DOORPLATE IMAGE SEGMENTATION IN MOBILE ROBOT NAVIGATION
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作者 Yang Guosheng Tan Min 《Journal of Electronics(China)》 2005年第5期505-512,共8页
Focused on the seed region selection and homogeneity criterion in Seeded Region Growing (SRG), an unsupervised seed region selection and a polynomial fitting homogeneity criterion for SRG are proposed in this paper. F... Focused on the seed region selection and homogeneity criterion in Seeded Region Growing (SRG), an unsupervised seed region selection and a polynomial fitting homogeneity criterion for SRG are proposed in this paper. First of all, making use of Peer Group Filtering (PGF) techniques, an unsupervised seed region selection algorithm is presented to construct a seed region. Then based on the constructed seed region a polynomial fitting homogeneity criterion is applied to solve the concrete problem of doorplate segmentation appearing in the robot navigation along a corridor. At last, experiments are performed and the results demonstrate the effectiveness of the proposed algorithm. 展开更多
关键词 Image segmentation Seeded Region Growing (SRG) Peer Group Filtering(PGF) Polynomial approximation
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Robust Stability Analysis of a Kind of Combined Integrating Control System
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作者 任正云 贾永基 《Journal of Donghua University(English Edition)》 EI CAS 2009年第4期397-401,共5页
This paper offeres an exact study on the robust stability of a kind of combined integrating control system, and the robust stability belongs to the analysis of a kind of quasi-polynomial with two independent time dela... This paper offeres an exact study on the robust stability of a kind of combined integrating control system, and the robust stability belongs to the analysis of a kind of quasi-polynomial with two independent time delays. The parameters of stable space under time delay uncertainty are fixed after Rekasius transformation, and then a new cluster treatment of characteristic roots (CTCR) procedure is adopted to determine the stable space. By this strategy we find that the unstable space is not continuous and both Karitonov vertices theory and Edge theory are unable to be extended to quasi-polynomial under time delay uncertainty. 展开更多
关键词 combined integrating control system robust stability quasi-polynomial multiple time delay
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Another Elementary Proof of the Stability Criterion of Liénard and Chipart
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作者 贾利新 《Chinese Quarterly Journal of Mathematics》 CSCD 1999年第3期76-79, ,共4页
Using the theory of polynomials,this paper gives a new necessary and sufficient condition for a polynomial to be Hurwitz polynomial,a simple proof of the stability criterion of Liénard and Chipart is also obtained.
关键词 Hurwitz polynomial polynomials of the first kind stability criterion of Liénard and Chipart
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On Turán type inequality with doubling weights and A weights
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作者 虞旦盛 韦宝荣 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第7期764-768,共5页
Let Hn be the set of real algebraic polynomials of degree n, whose zeros all lie in the interval [-1,1]. The well known Turán type inequalities tell us that forf(x)∈Hn, it holds ‖f'‖≥C√n‖f‖. This note d... Let Hn be the set of real algebraic polynomials of degree n, whose zeros all lie in the interval [-1,1]. The well known Turán type inequalities tell us that forf(x)∈Hn, it holds ‖f'‖≥C√n‖f‖. This note deals with the weighted Turán type inequalities with the weights having inner singularities under L^p norm for 0〈p≤∞. Our results essentially extend the result of Wang and Zhou (2002), and the method used in this paper is simpler and more direct than that of Wang and Zhou (2002). The results and methods have their own values in approximation theory and computation. 展开更多
关键词 Turán type inequality Doubling weights A weights
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Quasi-Periodic Structures Based on Symmetrical Lucas Function of (2+1)-Dimensional Modified Dispersive Water-Wave System
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作者 Emad A-B.ABDEL-SALAM 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第12期1004-1012,共9页
By introducing the Lucas-Riccati method and a linear variable separation method, new variable separation solutions with arbitrary functions are derived for a (2+1)-dimensional modified dispersive water-wave system.... By introducing the Lucas-Riccati method and a linear variable separation method, new variable separation solutions with arbitrary functions are derived for a (2+1)-dimensional modified dispersive water-wave system. The main idea of this method is to express the solutions of this system as polynomials in the solution of the Riecati equation that the symmetrical Lucas functions satisfy. From the variable separation sohition and by selecting appropriate functions, some novel Jacobian elliptic wave structure with variable modulus and their interactions with dromions and peakons are investigated. 展开更多
关键词 Lucas functions quasi-periodic structure variable separation excitations modified dispersive water-wave system
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On the Filtration Dimensions of a Standardly Stratified Algebra and Its Polynomial Algebra 被引量:1
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作者 康娜 姚海楼 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2006年第3期440-450,共11页
This paper deals with Δ-good filtration dimensions of a standardly stratified algebra and Δ[x]-good titration dimensions of its polynomial algebra.
关键词 standardly stratified algebras filtration dimensions polynomial algebras quasihereditary algebras.
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On deep holes of standard Reed-Solomon codes 被引量:10
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作者 WU RongJun HONG ShaoFang 《Science China Mathematics》 SCIE 2012年第12期2447-2455,共9页
Determining deep holes is an important open problem in decoding Reed-Solomon codes. It is well known that the received word is trivially a deep hole if the degree of its Lagrange interpolation polynomial equals the di... Determining deep holes is an important open problem in decoding Reed-Solomon codes. It is well known that the received word is trivially a deep hole if the degree of its Lagrange interpolation polynomial equals the dimension of the Reed-Solomon code. For the standard Reed-Solomon codes [p-1, k]p with p a prime, Cheng and Murray conjectured in 2007 that there is no other deep holes except the trivial ones. In this paper, we show that this conjecture is not true. In fact, we find a new class of deep holes for standard Reed-Solomon codes [q-1, k]q with q a power of the prime p. Let q≥4 and 2≤k≤q-2. We show that the received word u is a deep hole if its Lagrange interpolation polynomial is the sum of monomial of degree q-2 and a polynomial of degree at most k-1. So there are at least 2(q-1)qk deep holes if k q-3. 展开更多
关键词 deep hole Reed-Solomon code cyclic code BCH code DFT IDFT
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Karhunen-Loeve expansions for the m-th order detrended Brownian motion 被引量:2
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作者 AI XiaoHui LI WenBo V. 《Science China Mathematics》 SCIE 2014年第10期2043-2052,共10页
The m-th order detrended Brownian motion is defined as the orthogonal component of projection of the standard Brownian motion onto the subspace spanned by polynomials of degree up to m. We obtain the Karhunen-Loeve ex... The m-th order detrended Brownian motion is defined as the orthogonal component of projection of the standard Brownian motion onto the subspace spanned by polynomials of degree up to m. We obtain the Karhunen-Loeve expansion for the process and establish a connection with the generalized (m-th order) Brownian bridge developed by MacNeill (1978) in the study of distributions of polynomial regression. The resulting distribution identity is also verified by a stochastic Fubini approach. As applications, large and small deviation asymptotic behaviors for the L2 norm are given. 展开更多
关键词 m-th order detrended Brownian motion Karhunen-Loeve expansions stochastic Fubini approach Zeilberger algorithm large deviation small deviation
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Hypercube and Tetrahedron Algebra
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作者 Bo HOU Suogang GAO 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2015年第2期293-306,共14页
Let D be an integer at least 3 and let H(D, 2) denote the hypercube. It is known that H(D, 2) is a Q-polynomial distance-regular graph with diameter D, and its eigenvalue sequence and its dual eigenvalue sequence are ... Let D be an integer at least 3 and let H(D, 2) denote the hypercube. It is known that H(D, 2) is a Q-polynomial distance-regular graph with diameter D, and its eigenvalue sequence and its dual eigenvalue sequence are all {D-2i}D i=0. Suppose that denotes the tetrahedron algebra. In this paper, the authors display an action of ■ on the standard module V of H(D, 2). To describe this action, the authors define six matrices in Mat X(C), called A, A*, B, B*, K, K*.Moreover, for each matrix above, the authors compute the transpose and then compute the transpose of each generator of ■ on V. 展开更多
关键词 Tetrahedron algebra HYPERCUBE Distance-regular graph Onsager algebra
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On Non-standard Hilbert Functions
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作者 Amir Bagheri Rahim Rahmati-Asghar 《Algebra Colloquium》 SCIE CSCD 2018年第1期71-80,共10页
. Let S = k[x1,..., xn] be a non-standard polynomial ring over a field k and let M be a finitely generated graded S-module. In this paper, we investigate the behaviour of Hilbert function of M and its relations with l... . Let S = k[x1,..., xn] be a non-standard polynomial ring over a field k and let M be a finitely generated graded S-module. In this paper, we investigate the behaviour of Hilbert function of M and its relations with lattice point counting. More precisely, by using combinatorial tools, we prove that there exists a polytope such that the image of Hilbert function in some degree is equal to the number of lattice points of this polytope. 展开更多
关键词 polynomial ring non-standard Hilbert function Hermite normal form
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A CRITERION FOR TESTING WHETHER A DIFFERENCE IDEAL IS PRIME
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作者 Chunming YUAN Xiao-Shan GAO Key Laboratory of Mathematics Mechanization,Institute of Systems Science Academy of Mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100190,China. 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2009年第4期627-635,共9页
This paper presents a criterion for testing the irreducibility of a polynomial over an algebraicextension field.Using this criterion and the characteristic set method,the authors give a criterion fortesting whether ce... This paper presents a criterion for testing the irreducibility of a polynomial over an algebraicextension field.Using this criterion and the characteristic set method,the authors give a criterion fortesting whether certain difference ascending chains are strong irreducible,and as a consequence,whetherthe saturation ideals of these ascending chains are prime ideals. 展开更多
关键词 Characteristic set difference prime ideal IRREDUCIBILITY strong irreducibility.
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