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Decentralized Control of Compartmental Networks With H_∞ Tracking Performance

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS 2013年第2期60卷 546-553页

作者： Li, Ping Lam, James Univ Hong Kong Dept Mech Engn Pokfulam Hong Kong Peoples R China

This paper studies the decentralized H-infinity control problem for a class of compartmental networks, where the controller gain matrix is required to be diagonal and elementwise restricted. To solve the problem, we first propose a novel characterization under which the closed-loop system is asymptotically stable with a prescribed H-infinity performance. Then, a necessary and sufficient condition for the existence of a required controller is obtained, and an iterative linear matrix inequality approach is developed to solve the design condition. Moreover, a D-K iteration method is presented to optimize the initial value such that the solvability of the original problem can be further enhanced. Finally, the obtained results are illustrated through an application to a simple air traffic flow network model.

关键词： Compartmental networks decentralized structure H-infinity control iterative algorithm positive systems

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Approach for modeling accurate undeformed chip thickness in milling operation

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INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 2013年第5-8期68卷 1429-1439页

作者： Song, Ge Li, Jianfeng Sun, Jie Shandong Univ Sch Mech Engn Jinan 250061 Peoples R China Shandong Univ Minist Educ Key Lab High Efficiency & Clean Mech Manufacture Jinan 250061 Peoples R China

An accurate approach of the instantaneous undeformed chip thickness is a key issue for analyzing milling process. The presented models for approximating instantaneous undeformed chip thickness are oversimplified and complex for use in academic and manufacture practice. In this paper, a new model for determining the undeformed chip thickness in milling process with higher accuracy is proposed. According to the true trochoid path of tool tooth, the true instantaneous undeformed chip thickness can be derived by solving the deduced transcendental equation. An iterational algorithm is used to approach the value in the transcendental equation with infinitesimal calculation error. Our main contributions include that the accurate positions of the geometric points of the undeformed chip profile with different level of width of cut are analyzed and derived, as well as the accurate undeformed chip thicknesses of the chip cross-section profile are approached by iterative algorithm. Case studies with different parameter combinations show that the new model has a higher accuracy compared with the presented models. With this innovative approach, a method of accurate prediction of the geometric profile and thickness of the undeformed chip profile in milling process is provided.

关键词： Milling Undeformed chip thickness True tooth trajectories iterative algorithm

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A deterministic annealing algorithm for approximating a solution of the linearly constrained nonconvex quadratic minimization problem

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NEURAL NETWORKS 2013年 39卷 1-11页

作者： Dang, Chuangyin Liang, Jianqing Yang, Yang City Univ Hong Kong Dept Syst Engn & Engn Management Kowloon Hong Kong Peoples R China Shanxi Univ Sch Comp & Informat Technol Taiyuan Peoples R China Xuzhou Inst Technol Sch Math & Phys Sci Xuzhou Peoples R China

A deterministic annealing algorithm is proposed for approximating a solution of the linearly constrained nonconvex quadratic minimization problem. The algorithm is derived from applications of a Hopfield-type barrier function in dealing with box constraints and Lagrange multipliers in handling linear equality constraints, and attempts to obtain a solution of good quality by generating a minimum point of a barrier problem for a sequence of descending values of the barrier parameter. For any given value of the barrier parameter, the algorithm searches for a minimum point of the barrier problem in a feasible descent direction, which has a desired property that the box constraints are always satisfied automatically if the step length is a number between zero and one. At each iteration, the feasible descent direction is found by updating Lagrange multipliers with a globally convergent iterative procedure. For any given value of the barrier parameter, the algorithm converges to a stationary point of the barrier problem. Preliminary numerical results show that the algorithm seems effective and efficient. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Nonconvex quadratic minimization Linear constraints Hopfield-type barrier function Lagrange multiplier Descent direction iterative algorithm

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Compressed sensing for SAR-based wideband three-dimensional microwave imaging system using non-uniform fast Fourier transform

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IET RADAR SONAR AND NAVIGATION 2013年第6期7卷 658-670页

作者： Kajbaf, Hamed Case, Joseph T. Yang, Zengli Zheng, Yahong Rosa Missouri Univ Sci & Technol Elect & Comp Engn Dept Rolla MO 65409 USA

A new compressed sensing (CS) image reconstruction method is proposed for high-resolution wideband three-dimensional synthetic aperture radar (SAR) imaging systems. In contrast to existing CS SAR methods that employ only a forward SAR transform in pre- or post-processing, the proposed method employs both forward SAR and reverse SAR (R-SAR) transforms in each CS iteration to improve the quality of reconstructed images. This study proposes a simple and elegant truncation repair method to combat the truncation error and utilises non-uniform fast Fourier transform to reduce the SAR and R-SAR transform errors, thereby ensuring the convergence of the CS algorithm and improving the quality of the reconstructed images. The proposed CS SAR method is applied to microwave and millimeter wave imaging systems for non-destructive evaluation of materials embedded in stratified media. Three different specimens under test are measured by conventional uniform sampling and by random under-sampling with 20% or 30% spatial points of the uniform sampling. The reconstructed images show that, albeit having much less measurement points, the proposed CS method achieves better image quality and lower background artefacts than the images reconstructed from the fully-sampled uniform measurements.

关键词： fast Fourier transforms image reconstruction image sampling iterative methods microwave imaging millimetre wave imaging radar imaging synthetic aperture radar compressed sensing compressed sensing CS image reconstruction method wideband three-dimensional microwave imaging system nonuniform fast Fourier transform high-resolution synthetic aperture radar forward transform reverse transforms R-SAR transform error truncation error millimeter wave imaging systems iterative algorithm nondestructive evaluation stratified media uniform sampling random sampling background artefacts fully-sampled uniform measurements

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A Fast Calibration Method for Triaxial Magnetometers

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2013年第11期62卷 2929-2937页

作者： Tabatabaei, Seyed Amir Hoseini Gluhak, Alexander Tafazolli, Rahim Univ Surrey Ctr Commun Syst Res Guildford GU2 7XH Surrey England

This paper presents a novel iterative calibration algorithm for triaxial magnetometers. The proposed algorithm estimates and compensates the effects of deterministic interference parameters using only nine distinct measurements. The results of our extensive simulations and empirical evaluations confirm that the proposed method outperforms conventional ellipsoid fitting based models both in terms of accuracy and reliability even in the presence of a moderate wideband noise. The algorithm also achieves considerably faster convergence, which makes it suitable for real-time applications. The algorithm performance is also shown to be independent of the initial guesses of the interference parameters.

关键词： Calibration iterative algorithm magnetic field measurement parameter estimation

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On the iterative refinement of matrix upper bounds for the solution of continuous coupled algebraic Riccati equations

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AUTOMATICA 2013年第7期49卷 2168-2175页

作者： Xu, Jianhong Xiao, MingQing So Illinois Univ Dept Math Carbondale IL 62901 USA

In this paper, we develop a new approach for the iterative refinement algorithm along with fully mathematical justificationS, which sharpens matrix solution upper bounds for the well-known continuous coupled algebraic Riccati equation (CCARE). Our methodology is studied within a broader framework recently proposed in Xu (in press). Several desirable properties of the algorithm are then established, which include the strict monotonicity and convergence of the sequences generated by the algorithm, thus strengthening the existing results in the literature for computing tighter matrix upper solution bounds for the CCARE. In addition, new admissibility conditions within the general framework are proposed, which guarantee tighter matrix upper solution bounds to be computed from the algorithm. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Coupled Riccati equation Matrix bound iterative algorithm

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Modelling volatility by variance decomposition

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JOURNAL OF ECONOMETRICS 2013年第2期175卷 142-153页

作者： Amado, Cristina Terasvirta, Timo Univ Minho P-4710057 Braga Portugal NIPE P-4710057 Braga Portugal Aarhus Univ Dept Econ & Business CREATES DK-8000 Aarhus C Denmark

In this paper, we propose two parametric alternatives to the standard GJR-GARCH model of Glosten et al. (1993), based on additive and multiplicative decompositions of the variance. They allow the variance of the model to have a smooth time-varying structure. The suggested parameterizations describe structural change in the conditional and unconditional variances where the transition between regimes over time is smooth. The main focus is on the multiplicative decomposition of the variance into an unconditional and conditional components. Estimation of the multiplicative model is discussed in detail. An empirical application to daily stock returns illustrates the functioning of the model. The results show that the 'long memory type behaviour' of the sample autocorrelation functions of the absolute returns can also be explained by deterministic changes in the unconditional variance. (C) 2013 Elsevier B.V. All rights reserved.

关键词： Conditional heteroskedasticity Nonlinear time series Maximum likelihood estimation iterative algorithm Time-varying parameter model

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Scalable Hierarchical Parallel algorithm for the Solution of Super Large-Scale Sparse Linear Equations

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JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME 2013年第2期80卷 020901-020901-8页

作者： Xu, Ran Liu, Bin Dong, Yuan Tsinghua Univ Dept Engn Mech Beijing 100084 Peoples R China Tsinghua Univ Dept Comp Sci & Technol Beijing 100084 Peoples R China

The parallel linear equations solver capable of effectively using 1000+ processors becomes the bottleneck of large-scale implicit engineering simulations. In this paper, we present a new hierarchical parallel master-slave-structural iterative algorithm for the solution of super large-scale sparse linear equations in a distributed memory computer cluster. Through alternatively performing global equilibrium computation and local relaxation, the specific accuracy requirement can be met in a few iterations. Moreover, each set/slave-processor majorly communicates with its nearest neighbors, and the transferring data between sets/slave-processors and the master-processor is always far below the communication between neighboring sets/slave-processors. The corresponding algorithm for implicit finite element analysis has been implemented based on the MPI library, and a super large 2-dimension square system of triangle-lattice truss structure under randomly distributed loadings is simulated with over 1 x 10(9) degrees of freedom (DOF) on up to 2001 processors of the "Exploration 100" cluster in Tsinghua University. The numerical experiments demonstrate that this algorithm has excellent parallel efficiency and high scalability, and it may have broad applications in other implicit simulations.

关键词： super large linear equations parallel computing finite element method iterative algorithm hierarchical

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On asymptotic contractions

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MATHEMATICAL NOTES 2013年第1-2期94卷 214-219页

作者： Kornev, A. A. Stepin, A. M. Moscow MV Lomonosov State Univ Moscow Russia

A constructive generalization of the contraction mapping principle to the case of mappings with arbitrary rate of contraction is given.

关键词： attractor contraction rate iterative algorithm dynamical system intermittency

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An Improved Traffic Matrix Decomposition Method with Frequency-Domain Regularization

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2013年第3期E96D卷 731-734页

作者： Wang, Zhe Hu, Kai Yin, Baolin Beihang Univ Sch Comp Sci & Engn State Key Lab Software Dev Environm Beijing Peoples R China

We propose a novel network traffic matrix decomposition method named Stable Principal Component Pursuit with Frequency-Domain Regularization (SPCP-FDR), which improves the Stable Principal Component Pursuit (SPCP) method by using a frequency-domain noise regularization function. An experiment demonstrates the feasibility of this new decomposition method.

关键词： traffic matrix stable principal component pursuit frequency-domain regularization iterative algorithm

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