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Control Design for Transient Performance

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IEEE/CAA Journal of Automatica Sinica 2023年第1期10卷 3-7页

作者： Qing-guo wang Institute of Artificial Intelligence and Future Networks Beijing Normal University Guangdong Key Lab of AI and Multi-Modal Data Processing BNU-HKBU United International CollegeZhuhai 519087China

CONTROL systems are everywhere – chemical plants,energy systems, manufacturing, homes and buildings,automobiles and trains, medical devices, cellular telephones and internet, aircraft and spacecraft. Recent developments in these fields bring up the systems with the unprecedented scope, scale and complexity such as cyber-physical and human systems, and the required control task becomes more challenging than ever [1]。

关键词： telephone automobile everywhere

Microstructure and mechanical properties of hot-rolled low-carbon steel containing Ti–Ca oxide particles: a comparison between base metal and HAZ

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Journal of Iron and Steel Research International 2020年第4期27卷 440-450页

作者： Chao wang Xin wang Jian Kang guo Yuan guo-dong wang The State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

The effect of inclusion-induced nucleation on hot-rolled steel base metal was evaluated in comparison with welding heataffected zone(HAZ).Microstructure and mechanical properties of hot-rolled low-carbon steel containing Ti–Ca oxide particles were *** results showed that inclusions in Ti–Ca deoxidized steel distributed dispersely and were effective for intragranular acicular ferrite *** hot rolling and controlled cooling conditions,microstructure in steel base metal was significantly refined and mainly consisted of acicular ferrite and intragranular bainite,which exhibited higher strength and excellent *** microstructural evolution behavior followed the process that acicular ferrite plates divided the austenite grain,intragranular bainite packets formed between interlocking acicular ferrite plates,and the remaining austenite decomposed into fine polygonal ferrite *** resultant complex microstructure improved the impact toughness *** comparison,in HAZ microstructure,laminar grain boundary ferrite having similar crystallography orientation showed adverse effect on toughness.

关键词： Low-carbon steel Ti–Ca oxide Hot rolling Mechanical property Acicular ferrite Heat-affected zone

Normal Form for Families of Hamiltonian Systems

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Acta Mathematica Sinica,English Series 2007年第7期23卷 1199-1216页

作者： Zhi guo wang Department of Mathematics Nanjing University School of Mathematical Sciences Suzhou University

We consider perturbations of integrable Hamiltonian systems in the neighborhood of normally parabolic invariant tori. Using the techniques of KAM-theory we prove that there exists a canonical transformation that puts the Hamiltonian in normal form up to a remainder of weighted order 2d ＋ 1. And some dynamical consequences are obtained.

关键词： KAM lower dimensional tori normal form resonant torus

Efficient Processing of Distributed Twig Queries Based on Node Distribution

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Journal of Computer Science & Technology 2017年第1期32卷 78-92页

作者： Xin Bi Xiang-guo Zhao guo-Ren wang College of Computer Science and Engineering Northeastern University Shenyang 110815 China

Massive XML data are increasingly generated for the representation, storage and exchange of web information. Twig query processing over massive XML data has become a research focus. However, most traditional algorithms cannot be directly implemented in a distributed manner. Some of the existing distributed algorithms generate a lot of useless intermediate results and execute many join operations of partial results in most cases; others require the priori knowledge of query pattern before XML partition, storage and query processing, which is impractical in the cases of large-scale data or frequent incoming new queries. To improve efficiency and scalability, in this paper, we propose a 3-phase distributed algorithm DisT3 based on node distribution mechanism to avoid unnecessary intermediate results. Furthermore, we propose a lightweight local index ReP with an enhanced XML partitioning approach using arbitrary partitioning strategy, and based on ReP we propose an improved 2-phase distributed algorithm DisT2ReP to further reduce the communication cost. After the performance guarantees are analyzed, extensive experiments are conducted to verify the efficiency and scalability of our proposed algorithms in distributed twig query applications.

关键词： XML twig query distributed computing node distribution

Optimal approximate merging of a pair of Bézier curves with G^2-continuity

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 554-561页

作者： Ping ZHU guo-zhao wang Institute of Computer Graphics and lmage Processing State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China

We present a novel approach for dealing with optimal approximate merging of two adjacent Bezier eurves with G^2-continuity. Instead of moving the control points, we minimize the distance between the original curves and the merged curve by taking advantage of matrix representation of Bezier curve＇s discrete structure, where the approximation error is measured by L2-norm. We use geometric information about the curves to generate the merged curve, and the approximation error is smaller. We can obtain control points of the merged curve regardless of the degrees of the two original curves. We also discuss the merged curve with point constraints. Numerical examples are provided to demonstrate the effectiveness of our algorithms.

关键词： Approximate merging Gl-continuity G^2-continuity Discrete subdivision Point constraints

Relation among C-curve characterization diagrams

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第10期8卷 1663-1670页

作者： CAO Juan wang guo-zhao Institute of Computer Graphics and Image Processing Department of Mathematics Zhejiang University Hangzhou 310027 China

As three control points are fixed and the fourth control point varies, the planar cubic C-curve may take on a loop, a cusp, or zero to two inflection points, depending on the position of the moving point. The plane can, therefore, be partitioned into regions labelled according to the characterization of the curve when the fourth point is in each region. This partitioned plane is called a "characterization diagram". By moving one of the control points but fixing the rest, one can induce different characterization diagrams. In this paper, we investigate the relation among all different characterization diagrams of cubic C-curves based on the singularity conditions proposed by Yang and wang (2004). We conclude that, no matter what the C-curve type is or which control point varies, the characterization diagrams can be obtained by cutting a common 3D characterization space with a corresponding plane.

关键词： Spline C-curve Characterization diagram Singularity

Optimal constrained multi-degree reduction of Bézier curves with explicit expressions based on divide and conquer

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 577-582页

作者： Lian ZHOU guo-jin wang Institute of Computer Graphics and Image Processing State Key Lab of CAD & CG Zhejiang University Hangzhou 310027 China

We decompose the problem of the optimal multi-degree reduction of Bézier curves with corners constraint into two simpler subproblems, namely making high order interpolations at the two endpoints without degree reduction, and doing optimal degree reduction without making high order interpolations at the two endpoints. Further, we convert the second subproblem into multi-degree reduction of Jacobi polynomials. Then, we can easily derive the optimal solution using orthonormality of Jacobi polynomials and the least square method of unequally accurate measurement. This method of 'divide and conquer' has several advantages including maintaining high continuity at the two endpoints of the curve, doing multi-degree reduction only once, using explicit approximation expressions, estimating error in advance, low time cost, and high precision. More importantly, it is not only deduced simply and directly, but also can be easily extended to the degree reduction of surfaces. Finally, we present two examples to demonstrate the effectiveness of our algorithm.

关键词： Bezier curves Multi-degree reduction Divide and conquer

Nonlinear Fractional-Order Dynamic Stability of Fluid-Conveying Pipes Constituted by the Viscoelastic Materials with Time-Dependent Velocity

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Acta Mechanica Solida Sinica 2022年第5期35卷 733-745页

作者： Ye Tang guo wang Qian Ding School of Mechanical Engineering Anhui Polytechnic UniversityWuhu241000China Department of Mechanics Tianjin UniversityTianjin300350China

Considering that the fluid-conveying pipes made of fractional-order viscoelastic material such as polymeric materials with pulsatile flow are widely applied in engineering,we focus on the stability and bifurcation behaviors in parametric resonance of a viscoelastic pipe resting on an elastic *** Riemann–Liouville fractional-order constitutive equation is used to accurately describe the viscoelastic *** on this,the nonlinear governing equations are established according to the Euler–Bernoulli beam theory and von Karman’s nonlinearity,with using the generalized Hamilton’s *** stability boundaries and steady-state responses undergoing parametric excitations are determined with the aid of the direct multiple-scale *** numerical examples are carried out to show the effects of fractional order and viscoelastic coefficient on the stability region and nonlinear bifurcation *** is noticeable that the fractional-order viscoelastic property can effectively reconstruct the dynamic behaviors,indicating that the stability of the pipes can be conspicuously enhanced by designing and tuning the fractional order of viscoelastic materials.

关键词： Pipes conveying fluid Fractional-order viscoelastic damping Parametric vibration Stability Bifurcation

Growth and Spectral Properties of Nd^(3+) Doped KLa(MoO_4)_2 Crystal

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Chinese Journal of Structural Chemistry 2006年第2期25卷 192-196页

作者： wang guo-Jian HAN Xiu-Mei LONG Xi-Fa wang guo-Fu Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China

Nd^3＋ doped KLa（MoO4）2 single crystal with the size up to Ф25 × 40 mm^3 was grown by the Czochralski technique. The absorption and luminescence spectra of trivalent neodymium in KLa（MoO4）2 crystal were investigated at room temperature. The absorption and emission cross 10-20 sections are 3.02 ×10^-20 cm^2 at 808 nm and 20.01 × 10^-2 cm^2 at 1061 nm, respectively. The fluorescence lifetime is 164μs at room temperature.

关键词： Nd^3+ :KLa(MoO4)2 crystal crystal growth spectral properties