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基于灰度共生矩阵的纹理特征提取 被引量:175
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作者 高程程 惠晓威 《计算机系统应用》 2010年第6期195-198,共4页
纹理广泛存在于自然界中,是物体表面最本质的属性。纹理分析技术一直是热门的研究领域,纹理特征提取作为纹理分析的首要任务更是人们研究的焦点。针对五种木材纹理提出了用灰度共生矩阵的方法提取纹理特征,通过MATLAB仿真实现,结果表明... 纹理广泛存在于自然界中,是物体表面最本质的属性。纹理分析技术一直是热门的研究领域,纹理特征提取作为纹理分析的首要任务更是人们研究的焦点。针对五种木材纹理提出了用灰度共生矩阵的方法提取纹理特征,通过MATLAB仿真实现,结果表明由灰度共生矩阵产生的四个纹理特征能有效的描述木材的纹理特征,具有较好的鉴别能力。 展开更多
关键词 纹理 纹理特征 特征提取 纹理分析 灰度共生矩阵
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Semi-tensor product of matrices and its application to Morgen's problem 被引量:52
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作者 程代展 《Science in China(Series F)》 2001年第3期195-212,共18页
This paper proposes a new matrix product, namely, semi-tensor product. It is a general-ization of the conventional matrix product. Meanwhile, it is also closely related to Kronecker (tensor) product of matrices. The p... This paper proposes a new matrix product, namely, semi-tensor product. It is a general-ization of the conventional matrix product. Meanwhile, it is also closely related to Kronecker (tensor) product of matrices. The purpose of introducing this product is twofold: (i) treat multi-dimensional da-ta; (ii) treat nonlinear problems in a linear way. Then the computer and numerical methods can be easily used for solving nonlinear problems. Properties and formulas are deduced. As an application, the Morgan's problem for control systems is formulated as a numerically solvable problem. 展开更多
关键词 swap matrix left-semi-tensor product mapping of matrices decoupling matrix Morgen's problem.
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拖拉机抗性消声器声学子结构声传递矩阵研究 被引量:16
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作者 蔡超 宫镇 +1 位作者 赵剑 曾发林 《农业机械学报》 EI CAS CSCD 北大核心 1994年第2期65-72,共8页
以消声器传递矩阵分析方法为基础,给出了12种拖拉机抗性消声器声学子结构的声传递矩阵。以传递损失为评价指标,实验验证了两个消声器的声学性能。本文研究结果,为进行拖拉机抗性消声器的优化设计创造了条件。
关键词 拖拉机 消声器 声学 矩阵
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求解大规模矩阵问题的Krylov子空间方法 被引量:18
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作者 戴华 《南京航空航天大学学报》 EI CAS CSCD 北大核心 2001年第2期139-145,共7页
求解大规模矩阵问题包括线性方程组和特征值问题等是计算数学和科学工程计算中的重大课题。最近几年 ,其研究工作取得了许多重大进展。文中给出大型线性方程组和特征值问题 Krylov子空间方法若干进展的一个概述 ,其中包括作者对这些问... 求解大规模矩阵问题包括线性方程组和特征值问题等是计算数学和科学工程计算中的重大课题。最近几年 ,其研究工作取得了许多重大进展。文中给出大型线性方程组和特征值问题 Krylov子空间方法若干进展的一个概述 ,其中包括作者对这些问题的研究成果。涉及的专题包括求解大型线性方程组的共轭梯度法、SYMMLQ算法、MINRES算法、GMRES算法、Lanczos双正交化算法、QMR算法以及这些算法的块格式 ;求解大型对称特征值问题的 Lanczos算法和块 Lanczos算法 ;求解大型非对称特征值问题的 Lanczos算法、Arnoldi算法以及这些算法的块推广。讨论求解大规模矩阵问题的加速技术和预处理技术。 展开更多
关键词 线性方程组 特征值 KRYLOV子空间方法 大规模矩阵
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Contraction Integrated Semigroups and Their Applicationto Continuous-time Markov Chains 被引量:31
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作者 YangRongLI 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2003年第3期605-618,共14页
We introduce the notion of the contraction integrated semigroups and give the Lumber-Phillips characterization of the generator, and also the charaterazied generators of isometric integrated semigroups. For their appl... We introduce the notion of the contraction integrated semigroups and give the Lumber-Phillips characterization of the generator, and also the charaterazied generators of isometric integrated semigroups. For their application, a necessary and sufficient condition for q-matrices Q generating a contraction integrated semigroup is given, and a necessary and sufficient condition for a transition function to be a Feller-Reuter-Riley transition function is also given in terms of its q-matrix. 展开更多
关键词 Keywords Integrated semigroups Contraction integrated semigroups Markov chains Transition functions q matrices Feller Reuter Riley transition functions
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水深、基质、光和去苗对菹草石芽萌发的影响 被引量:31
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作者 简永兴 王建波 +1 位作者 何国庆 陈家宽 《水生生物学报》 CAS CSCD 北大核心 2001年第3期224-229,共6页
通过野外调查 ,研究了水深对菹草石芽萌发率的影响 ,比较了梁子湖与湖北省其他四个不同水深的湖泊间菹草石芽萌发率月动态 ;并通过萌发实验探讨了基质、光和去苗对菹草石芽萌发的影响。结果如下 :无光环境下菹草石芽的萌发率较有光下的... 通过野外调查 ,研究了水深对菹草石芽萌发率的影响 ,比较了梁子湖与湖北省其他四个不同水深的湖泊间菹草石芽萌发率月动态 ;并通过萌发实验探讨了基质、光和去苗对菹草石芽萌发的影响。结果如下 :无光环境下菹草石芽的萌发率较有光下的小 ,基质的有无及其类型对萌发率影响不大 ,去苗能使其萌发第二苗和第三苗的百分率分别从自然状况下的3.2 %和 1 .0 %提高至 96.8%和 64.0 % ( 1 2月初 ) ;五个湖泊的石芽均于 7月初即开始萌发 ,相同月份不同湖泊石芽的平均萌发率基本与其平均水深成负相关关系 ,但 1 2月初各湖泊的平均萌发率相近 ( >95% ) ;同一湖泊水深越大 ,相同月份的萌发率越低 ,水深的增加能显著推迟萌发起始时间 ,但不改变其最终萌发率 ( 1 2月初 >95% )。菹草石芽高萌发率的特征和极高的萌发第二、第三苗的潜力可能是其成为许多湖泊优势种的两个极其重要的维持机制。 展开更多
关键词 水深梯度 基质 去苗 菹草 石芽 萌发 水草 沉水植物
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Systematic Geometric Error Modeling for Workspace Volumetric Calibration of a 5-axis Turbine Blade Grinding Machine 被引量:30
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作者 Abdul Wahid Khan 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2010年第5期604-615,共12页
A systematic geometric model has been presented for calibration of a newly designed 5-axis turbine blade grinding machine. This machine is designed to serve a specific purpose to attain high accuracy and high efficien... A systematic geometric model has been presented for calibration of a newly designed 5-axis turbine blade grinding machine. This machine is designed to serve a specific purpose to attain high accuracy and high efficiency grinding of turbine blades by eliminating the hand grinding process. Although its topology is RPPPR (P: prismatic; R: rotary), its design is quite distinct from the competitive machine tools. As error quantification is the only way to investigate, maintain and improve its accuracy, calibra- tion is recommended for its performance assessment and acceptance testing. Systematic geometric error modeling technique is implemented and 52 position dependent and position independent errors are identified while considering the machine as five rigid bodies by eliminating the set-up errors of workpiece and cutting tool. 39 of them are found to have influential errors and are accommodated for finding the resultant effect between the cutting tool and the workpiece in workspace volume. Rigid body kinematics techniques and homogenous transformation matrices are used for error synthesis. 展开更多
关键词 5-axis machine tools CALIBRATION modeling geometric errors kinematics homogenous transformation matrices
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环上矩阵的广义Moore-Penrose逆 被引量:25
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作者 刘淑丹 游宏 《数学杂志》 CSCD 北大核心 2002年第1期116-120,共5页
本文给出带有对合的有 1的结合环上一类矩阵的广义 Moore- Penrose逆存在的充要条件 ,而这类矩阵概括了左右主理想整环 ,单
关键词 广义MOORE-PENROSE逆 结合环 矩阵 单Artin环
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M-矩阵的等价表征 被引量:20
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作者 逄明贤 孙玉祥 《应用数学》 CSCD 北大核心 1995年第1期44-50,共7页
本文引进了按环路弱不可约非零元素链对角占优的概念,讨论了M-矩阵的等价条件,给出了M-矩阵的两个等价表征,改进与推广了[1]、[2]、[5]、[9]的相应结果。
关键词 对角占优 有向图 M矩阵 G函数 弱不可约矩阵
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海藻酸钠骨架材料中药物释放的影响因素 被引量:20
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作者 聂淑芳 吴学明 +2 位作者 刘宏飞 姜华威 潘卫三 《药学学报》 CAS CSCD 北大核心 2004年第7期561-565,共5页
目的 以海藻酸钠为亲水骨架材料 ,考察药物从海藻酸钠骨架片中释放的体外影响因素。方法 以茶碱为模型药物 ,采用直接压片法制备了茶碱海藻酸钠亲水骨架片 ,通过对骨架片膨胀性、吸水性以及溶蚀性的考察 ,研究了影响药物从海藻酸钠骨... 目的 以海藻酸钠为亲水骨架材料 ,考察药物从海藻酸钠骨架片中释放的体外影响因素。方法 以茶碱为模型药物 ,采用直接压片法制备了茶碱海藻酸钠亲水骨架片 ,通过对骨架片膨胀性、吸水性以及溶蚀性的考察 ,研究了影响药物从海藻酸钠骨架材料中释放的体外因素。结果 茶碱海藻酸钠骨架片的释药速率和释药机理与骨架片中海藻酸钠粘度、释放介质pH值、离子强度以及转速均有关。结论 海藻酸钠能有效地控制骨架片中药物的释放 。 展开更多
关键词 海藻酸钠 茶碱 骨架片 体外释放
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分光光度法测定不同食品基质中亚硝酸盐含量 被引量:23
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作者 任韧 金铨 +3 位作者 龚立科 薛鸣 樊继彩 黄希汇 《中国食品卫生杂志》 2016年第4期480-484,共5页
目的建立测定不同食品基质中亚硝酸盐含量的分光光度法。方法取适量样品,按不同基质进行提取和净化,用分光光度法测定亚硝酸盐含量(以亚硝酸钠计)。结果方法检出限:液态乳和发酵乳中为0.02 mg/kg,其他样品中为0.2 mg/kg。淀粉类样品... 目的建立测定不同食品基质中亚硝酸盐含量的分光光度法。方法取适量样品,按不同基质进行提取和净化,用分光光度法测定亚硝酸盐含量(以亚硝酸钠计)。结果方法检出限:液态乳和发酵乳中为0.02 mg/kg,其他样品中为0.2 mg/kg。淀粉类样品在添加浓度1.0-5.0 mg/kg范围内,回收率为77.6%-113%,RSD为1.9%-13.4%;肉制品类样品在添加浓度2.0-10.0 mg/kg范围内,回收率为77.5%-111.5%,RSD为2.1%-7.8%;腌菜类样品在添加浓度2.0-10.0 mg/kg范围内,回收率为58.5%-78.1%,RSD为4.0%-12.5%;液态乳、发酵乳类样品在添加浓度0.2-1.0 mg/kg范围内,回收率为81.5%-98.8%,RSD为1.4%-8.1%。结论该方法对不同食品基质样品的前处理方法进行了优化,干扰少,准确度、灵敏度高,能满足各类食品中亚硝酸盐的测定。 展开更多
关键词 食品 基质 亚硝酸盐 分光光度法 测定 食品安全
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环上矩阵的Moore-Penrose逆 被引量:16
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作者 刘晓冀 刘三阳 王志坚 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2003年第4期728-730,共3页
本文研究环上矩阵的广义逆,得到其存在的充要条件,给出它的表达式,推广了以往文献的相应结果。
关键词 矩阵 Moore—Penrose逆
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Semi-tensor product approach to networked evolutionary games 被引量:18
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作者 Daizhan CHENG Hongsheng QI +2 位作者 Fehuang HE Tingting XU Hairong DONG 《Control Theory and Technology》 EI CSCD 2014年第2期198-214,共17页
In this paper a comprehensive introduction for modeling and control of networked evolutionary games (NEGs) via semi-tensor product (STP) approach is presented. First, we review the mathematical model of an NEG, wh... In this paper a comprehensive introduction for modeling and control of networked evolutionary games (NEGs) via semi-tensor product (STP) approach is presented. First, we review the mathematical model of an NEG, which consists of three ingredients: network graph, fundamental network game, and strategy updating rule. Three kinds of network graphs are considered, which are i) undirected graph for symmetric games; ii) directed graph for asymmetric games, and iii) d-directed graph for symmetric games with partial neighborhood information. Three kinds of fundamental evolutionary games (FEGs) are discussed, which are i) two strategies and symmetric (S-2); ii) two strategies and asymmetric (A-2); and iii) three strategies and symmetric (S-3). Three strategy updating rules (SUR) are introduced, which are i) Unconditional Imitation (UI); ii) Fermi Rule(FR); iii) Myopic Best Response Adjustment Rule (MBRA). First, we review the fundamental evolutionary equation (FEE) and use it to construct network profile dynamics (NPD)of NEGs. To show how the dynamics of an NEG can be modeled as a discrete time dynamics within an algebraic state space, the fundamental evolutionary equation (FEE) of each player is discussed. Using FEEs, the network strategy profile dynamics (NSPD) is built by providing efficient algorithms. Finally, we consider three more complicated NEGs: i) NEG with different length historical information, ii) NEG with multi-species, and iii) NEG with time-varying payoffs. In all the cases, formulas are provided to construct the corresponding NSPDs. Using these NSPDs, certain properties are explored. Examples are presented to demonstrate the model constructing method, analysis and control design technique, and to reveal certain dynamic behaviors of NEGs. 展开更多
关键词 Networked evolutionary game Fundamental evolutionary equation Strategy profile dynamics Homogeneous/heterogeneous NEG Semi-tensor product of matrices
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矩阵特征值反问题的若干进展 被引量:11
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作者 戴华 《南京航空航天大学学报》 CAS CSCD 1995年第3期400-413,共14页
给出矩阵特征值反问题若干进展的一个概述。涉及的专题包括合参数的特征值反问题、Jacobi矩阵和实对称带状矩阵特征值反问题和线性(谱)约束下矩阵(束)逼近问题。这些问题出现在各种应用领域,如粒子物理的核光谱学、结构设计... 给出矩阵特征值反问题若干进展的一个概述。涉及的专题包括合参数的特征值反问题、Jacobi矩阵和实对称带状矩阵特征值反问题和线性(谱)约束下矩阵(束)逼近问题。这些问题出现在各种应用领域,如粒子物理的核光谱学、结构设计、振动反问题、Sturm-Liouville反问题和数学物理反问题的离散化以及结构动力模型的校正。最近20年,对这些问题的提法逐渐完善,解的存在性和数值方法方面已取得了许多重要进展。本文评述这些问题的一些理论结果和数值方法。 展开更多
关键词 数值代数 矩阵 特征值 反问题
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基于方向余弦参量的物坐标系与世界坐标系间的坐标变换 被引量:14
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作者 许社教 张郁 《工程图学学报》 CSCD 2004年第1期123-127,共5页
借助物体上三点建立了物坐标系,并给出了其坐标轴的方向余弦计算式。利用矢量代数的方法,推导出以方向余弦为参量的物坐标系到世界坐标系的坐标变换矩阵;利用矩阵求逆的方法,推导出世界坐标系到物坐标系的坐标变换矩阵。作为推论,推导... 借助物体上三点建立了物坐标系,并给出了其坐标轴的方向余弦计算式。利用矢量代数的方法,推导出以方向余弦为参量的物坐标系到世界坐标系的坐标变换矩阵;利用矩阵求逆的方法,推导出世界坐标系到物坐标系的坐标变换矩阵。作为推论,推导出两种特殊情况的坐标变换矩阵。文中推出的物坐标系与世界坐标系间的两个变换矩阵可作为任意两个坐标系间的坐标变换矩阵,故具有通用性。 展开更多
关键词 工程图学 坐标变换 矩阵 矢量代数 方向余弦参量 物坐标系 世界坐标系
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Preparation and Characterization of Collagen-GAGs Bioactive Matrices for Tissue Engineering 被引量:7
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作者 Hongyi YANG and Qiqing ZHANG Institute of Biomedical Engineering, Chinese Academy of Medical Science, Tianjin 300192, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2001年第5期495-500,共6页
Collagen materials were crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) in the presence of chondroitin sulfate (CS), one of glycosaminoglycans (GAGS). PVA and chitosan were also blended with colla... Collagen materials were crosslinked by 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) in the presence of chondroitin sulfate (CS), one of glycosaminoglycans (GAGS). PVA and chitosan were also blended with collagen. The physical and chemical properties of the matrices were characterized by SEM, DSC, and ESCA. L929 cells were implanted on the matrices to show the cytotoxic and the biological characters of the materials. The results indicate that EDC is an effective and non-cytotoxic cross-link reagent, which can replace the common dialdehyde reagent. The attachment of CS can improve the stability of collagen and accelerate cell growth. The addition of PVA can prepare porous matrices with smaller bore size. There are reactions between the chitosan and collagen, and the composite has good biological character. The presence of chitosan can also increase the amount of incorporated CS. 展开更多
关键词 Preparation and Characterization of Collagen-GAGs Bioactive matrices for Tissue Engineering PVA EDC CS
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环上矩阵的广义Moore-Penrose逆 被引量:12
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作者 王志坚 刘晓冀 《数学杂志》 CSCD 北大核心 2004年第6期638-640,共3页
本文研究环上矩阵的广义Moore -Penros逆 ,利用矩阵行空间与列空间的包含关系 ,给出其存在的充要条件及表达式 ,推广了以往文献的相应结果 .
关键词 矩阵 广义MOORE-PENROSE逆
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子空间旋转的最小二乘问题 被引量:12
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作者 张磊 谢冬秀 《湖南大学学报(自然科学版)》 EI CAS CSCD 1992年第1期115-120,共6页
本文研究了子空间旋转的最小二乘逼近解,给出了解的表达式及其算法.
关键词 矩阵 最小二乘法 奇异值分解 逼近
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Blind recognition of k/n rate convolutional encoders from noisy observation 被引量:13
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作者 Li Huang Wengu Chen +1 位作者 Enhong Chen Hong Chen 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第2期235-243,共9页
Blind recognition of convolutional codes is not only essential for cognitive radio, but also for non-cooperative context. This paper is dedicated to the blind identification of rate k/n convolutional encoders in a noi... Blind recognition of convolutional codes is not only essential for cognitive radio, but also for non-cooperative context. This paper is dedicated to the blind identification of rate k/n convolutional encoders in a noisy context based on Walsh-Hadamard transformation and block matrix (WHT-BM). The proposed algorithm constructs a system of noisy linear equations and utilizes all its coefficients to recover parity check matrix. It is able to make use of fault-tolerant feature of WHT, thus providing more accurate results and achieving better error performance in high raw bit error rate (BER) regions. Moreover, it is more computationally efficient with the use of the block matrix (BM) method. © 2017 Beijing Institute of Aerospace Information. 展开更多
关键词 Cognitive radio CONVOLUTION Convolutional codes Error correction Hadamard matrices Hadamard transforms Linear transformations Mathematical transformations Matrix algebra Signal encoding
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Orthogonal arrays obtained by generalized difference matrices with g levels 被引量:11
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作者 ZHANG YingShan LI WeiGuo +1 位作者 MAO ShiSong ZHENG ZhongGuo 《Science China Mathematics》 SCIE 2011年第1期133-143,共11页
Nowadays orthogonal arrays play important roles in statistics, computer science, coding theory and cryptography. The usual difference matrices are essential for the construction for many mixed orthogonal arrays. But t... Nowadays orthogonal arrays play important roles in statistics, computer science, coding theory and cryptography. The usual difference matrices are essential for the construction for many mixed orthogonal arrays. But there are also orthogonal arrays which cannot be obtained by the usual difference matrices, such as mixed orthogonal arrays of run size 60. In order to construct these mixed orthogonal arrays, a class of special so-called generalized difference matrices were discovered by Zhang (1989,1990,1993,2006) from the orthogonal decompositions of projection matrices. In this article, an interesting equivalent relationship between orthogonal arrays and the generalized difference matrices is presented and proved. As an application, a lot of new orthogonal arrays of run size 60 have been constructed. 展开更多
关键词 mixed-level orthogonal arrays generalized difference matrices projection matrices permutation matrices
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