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Mathematical Foundations for Efficient Structural Controllability and Observability Analysis of Complex Systems

MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-12页

作者： Zufiria, Pedro J. Ubeda-Medina, Luis Herrera-Yaguee, Carlos Barriales-Valbuena, Iker Univ Politecn Madrid ETSI Telecomunicac Dept Matemat Aplicada Tecnol Informac E-28040 Madrid Spain Univ Politecn Madrid ETSI Telecomunicac Catedra Orange E-28040 Madrid Spain MIT Dept Civil & Environm Engn Cambridge MA 02139 USA

The relationship between structural controllability and observability of complex systems is studied. Algebraic and graph theoretic tools are combined to prove the extent of some controller/observer duality results. Two types of control design problems are addressed and some fundamental theoretical results are provided. In addition new algorithms are presented to compute optimal solutions for monitoring large scale real networks.

关键词： STRUCTURAL control (Engineering) GRAPH theory PID controllers computer algorithms LARGE scale systems DUALITY theory (Mathematics) MATHEMATICAL proofs

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Direct active and reactive power control of single-phase grid-tie converters

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IET POWER ELECTRONICS 2012年第8期5卷 1544-1550页

作者： Monfared, M. Sanatkar, M. Golestan, S. Ferdowsi Univ Mashhad Dept Elect Engn Fac Engn Mashhad Iran Islamic Azad Univ Abadan Branch Dept Elect Engn Abadan Iran

In this study, a simple digital power control technique for single-phase grid-tie converters is proposed. The suggested technique is based on the application of dead-beat control theory to the instantaneous powers in the virtual two-axis reference frame. A voltage estimation scheme is added to the proposed direct power control algorithm that allows grid voltage sensorless operation. The simulation and experimental results confirm that the proposed control strategy provides fast, accurate and decoupled power control with a lower alternating current distortion.

关键词： Active instantaneous power control strategy gate voltage Power control direct power Reactive power control Control technology dead-beat Converters computer algorithms

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An Improved Adaptive Deconvolution Algorithm for Single Image Deblurring

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-11页

作者： Tsai, Hsin-Che Wu, Jiunn-Lin Natl Chung Hsing Univ Dept Comp Sci & Engn Taichung 40227 Taiwan

One of the most common defects in digital photography is motion blur caused by camera shake. Shift-invariant motion blur can be modeled as a convolution of the true latent image and a point spread function (PSF) with additive noise. The goal of image deconvolution is to reconstruct a latent image from a degraded image. However, ringing is inevitable artifacts arising in the deconvolution stage. To suppress undesirable artifacts, regularization based methods have been proposed using natural image priors to overcome the ill-posedness of deconvolution problem. When the estimated PSF is erroneous to some extent or the PSF size is large, conventional regularization to reduce ringing would lead to loss of image details. This paper focuses on the nonblind deconvolution by adaptive regularization which preserves image details, while suppressing ringing artifacts. The way is to control the regularization weight adaptively according to the image local characteristics. We adopt elaborated reference maps that indicate the edge strength so that textured and smooth regions can be distinguished. Then we impose an appropriate constraint on the optimization process. The experiments' results on both synthesized and real images show that our method can restore latent image with much fewer ringing and favors the sharp edges.

关键词： ADAPTIVE computing systems DECONVOLUTION (Mathematics) computer algorithms IMAGE analysis DIGITAL photography CAMERAS

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HEURISTIC AND STATISTICAL algorithms FOR AUTOMATED EMISSION SPECTRAL BACKGROUND INTENSITY ESTIMATION

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APPLIED SPECTROSCOPY 1994年第8期48卷 915-925页

作者： SALIT, ML COLLINS, JB YATES, DA MACBETH PROC MEASUREMENTS NEWBURGHNY 12550 PERKIN ELMER CORP NORWALKCT 06859

Two algorithms for the complete automation of background estimation in ICP emission spectroscopy are presented and evaluated. One of these algorithms is based on heuristic spectral interpretation, while the other is based on statistical spectral interpretation. These algorithms both address the weaknesses of the conventionally employed approaches of blank subtraction in calibration and background estimation through interpolation from analyst-selected wavelengths adjacent to the analyte peak. In a rigorous evaluation with synthetic spectra, these algorithms are characterized for performance in terms of accuracy, precision, and robustness. As a demonstration of the algorithms' performance with experimentally measured spectra, a determination of uranium in the presence of a calcium background interference is performed. These algorithms require no analyst interaction for their operation, and they estimate the background for every spectrum measured.

关键词： EMISSION SPECTROSCOPY SPECTRAL INTERPRETATION BACKGROUND CORRECTION BASE-LINE FITTING computer algorithms SYNTHETIC SPECTRA EXPERIMENTS INDUCTIVELY COUPLED PLASMA

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Effective force testing: A method of seismic simulation for structural testing

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JOURNAL OF STRUCTURAL ENGINEERING-ASCE 1999年第9期125卷 1028-1037页

作者： Dimig, J Shield, C French, C Bailey, F Clark, A Wiss Janney Elstner & Associates Northbrook IL 60062 USA Univ Minnesota Dept Civil Engn Minneapolis MN 55455 USA Univ Minnesota Dept Elect Engn Minneapolis MN 55455 USA MTS Syst Corp Adv Syst Div Eden Prairie MN 55344 USA

This paper presents a test method for real-time earthquake simulation studies of large scale test structures. The method, effective force testing (EFT), is based on a force control algorithm. For systems that can be modeled as a series of lumped masses (e.g., frame structures where masses are assumed lumped at the floor levels), the EFT forces are known a priori for any acceleration record. As opposed to the pseudodynamic test method (a displacement-based control. procedure), there is no computational time required for the EFT method in determining the required force signal;it is known prior to the test once the structural mass and ground acceleration record to be simulated are determined. Research has been conducted on a single-degree-of-freedom system at the University of Minnesota to investigate the potential of the EFT method. A direct application of the method was found ineffective because the actuator was unable to apply force at the natural frequency of the structure owing to actuator/control/structure interaction. However, numerical simulations and experimental implementation indicated that an additional velocity feedback loop incorporated into the control system can overcome this problem while maintaining the ability to do real-time testing.

关键词： floor levels control systems Force Electronic funds transfer Test Method TESTING TIME structural mass simulating Control procedures computer algorithms

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CONTINUOUS-TIME STOCHASTIC-MODEL REFERENCE ADAPTIVE-CONTROL

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IEEE TRANSACTIONS ON AUTOMATIC CONTROL 1991年第11期36卷 1254-1263页

作者： GOODWIN, GC MAYNE, DQ UNIV CALIF DAVIS DEPT ELECT ENGN & COMP SCIDAVISCA 95616 UNIV LONDON IMPERIAL COLL SCI & TECHNOL DEPT ELECT ENGNLONDON SW7 2AZENGLAND

There exist useful paradigms for establishing global convergence of adaptive controllers for linear, discrete-time, deterministic, and stochastic systems and linear continuous-time deterministic systems. More recently, global convergence of an indirect adaptive controller for continuous-time stochastic linear systems has been established. This paper completes this program by establishing global convergence and asymptotic properties of a direct adaptive controller for continuous-time stochastic linear systems. This result is comprehensive and covers many other existing results as special cases. It also has practical implications for the discrete-time case since it reveals how the existing discrete-time results must be modified so that they have meaningful limits as the sampling period decreases.

关键词： global convergence Writers adaptive controller discrete-time Mentoring asymptotic properties sampling interval adaptive control Linear system computer algorithms

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Specification and implementation of directional operators in a 3D spatial query language for building information models

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ADVANCED ENGINEERING INFORMATICS 2009年第1期23卷 32-44页

作者： Borrmann, Andre Rank, Ernst Tech Univ Munich D-80290 Munich Germany

A spatial query language enables the spatial analysis of building information models and the extraction of partial models that fulfill certain spatial constraints. Among other features, the developed spatial query language includes directional operators, i.e., operators that reflect the directional relationships between 3D spatial objects, such as northOf, southOf, eastOf, westOf, above and below. The paper presents in-depth definitions of the semantics of two new directional models for extended 3D objects, the projection-based and the halfspace-based model, by using point-set theory notation. It further describes the possible implementation of directional operators using a newly developed space-partitioning data structure called slot-tree, which is derived from the objects' octree representation. The slot-tree allows for the application of recursive algorithms that successively increase the discrete resolution of the spatial objects employed and thereby enables the user to trade-off between computational effort and the required accuracy. The article also introduces detailed investigations on the runtime performance of the developed algorithms. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： BUILDING information modeling QUERY languages (computer science) SPATIAL analysis (Statistics) THREE-dimensional imaging OPERATOR theory computer algorithms

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An efficient stabilized fast Newton adaptive filtering algorithm for stereophonic acoustic echo cancellation SAEC

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computerS & ELECTRICAL ENGINEERING 2012年第4期38卷 938-952页

作者： Djendi, Mohamed Univ Saad Dahleb Blida Signal Proc & Image Lab LATSI Blida 09000 Algeria

This paper addresses the field of stereophonic acoustic echo cancellation (SAEC) by adaptive filtering algorithms. Recently, we have proposed a new version of the fast Newton transversal FNTF algorithm for SAEC applications. In this paper, we propose an efficient modification of this algorithm for the same applications. This new algorithm uses a new proposed and simplified numerical stabilization technique and takes into account the cross-correlation between the inputs of the channels. The basic idea is to introduce a small nonlinearity into each channel that has the effect of reducing the inter-channel coherence while not being noticeable for speech due to self masking. The complexity of the proposed algorithm does not alter the complexity of the original version and is kept less than half the complexity of the fastest two-channel FTF filter version. Simulation results and comparisons with the extended two-channel normalized least mean square NLMS and FTF algorithms are presented. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： ELECTRIC filters computer algorithms STEREOPHONIC receivers ECHO suppression ENERGY consumption STATISTICAL correlation COMPARATIVE studies computer simulation

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A temperature-based controller for a shape memory alloy actuator

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JOURNAL OF VIBRATION AND ACOUSTICS-TRANSACTIONS OF THE ASME 2005年第3期127卷 285-291页

作者： Elahinia, MH Ashrafiuon, H Ahmadian, M Tan, HH Univ Toledo Mech Ind & Mfg Engn Dept Toledo OH 43606 USA Villanova Univ Dept Mech Engn Villanova PA 19085 USA Virginia Tech Dept Mech Engn Blacksburg VA 24061 USA Univ Toledo Mech Ind & Mfg Engn Dept Toledo OH 43606 USA

This paper presents a robust nonlinear control that uses a variable estimator for control of a single degree of freedom manipulator actuated by shape memory alloy (SMA) wire. A model for SMA actuated manipulator is presented The model includes nonlinear dynamics of the manipulator a constitutive model of the shape memory alloy, and the electrical and transfer behavior of SMA wire. The current experimental setup allows for the measurement of only one state variable which is the angular position of the arm. Due to measurement difficulties, the other three state variables, arm angular velocity and SMA wire stress and temperature, cannot be directly measured. A model-based state estimator that works with noisy measurements is presented based on the extended Kalman filter (EKF). This estimator estimates the state vector at each time step and corrects its estimation based on the angular position measurements. The estimator is then used in a nonlinear and robust control algorithm based on variable structure control (VSC). The VSC algorithm is a control gain switching technique based on the arm angular position (and velocity) feedback and EKF estimated SMA wire stress and temperature. Using simulation it is shown that the state vector estimates help reduce or avoid the undesirable and inefficient overshoot problem in SMA one-way actuation control.

关键词： Stone matrix asphalt Shape memory alloys state vectors Heat transfer Shape memory Variable structure control computer algorithms nonlinear control velocity feedback METAL ALLOY angular position ELECTRIC WIRE State estimation State variable

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The design and control of a jetting dispenser for semiconductor electronic packaging driven by a piezostack and a flexible beam

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SMART MATERIALS AND STRUCTURES 2008年第6期17卷 065028-1-065028-12-0页

作者： Nguyen, Quoc-Hung Choi, Seung-Bok Kim, Jae-Do Inha Univ Dept Mech Engn Inchon 402751 South Korea

This paper presents the performance characteristics of a new type of jetting dispenser which can be applicable for modern semiconductor packaging processes. The proposed jetting dispenser is driven by both a piezostack actuator and a flexible beam mechanism. After describing the geometric configuration and operational principle of the dispenser, a mathematical model of the system is derived by considering the dynamic behaviors of structural parts such as the piezostack, the flexible beam, the needle structure, and the adhesive fluid dynamics. In the modeling, a lumped parameter method is employed and the governing equation of the whole dispenser is then formulated by integrating the structural model with the fluid model. Based on the proposed model, significant structural components of the dispenser such as the piezostack, the flexible beam, and the actuating spring are designed in order to achieve operational requirements (needle motion amplitude: up to 0.4 mm;operating frequency: up to 700 Hz). Subsequently, dispensing performances such as the dispensing dot size and flow rate are experimentally evaluated. In addition, a control algorithm is designed and empirically realized to demonstrate some benefits of the proposed jetting dispenser such as accurate controllability of dispensing amount.

关键词： Dot Size performance characteristics Dispersers Structural parts FLEXIBLE Dispensing Governing equation computer algorithms Hydrodynamics

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