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IMAGE UNDERSTANDING AND INTERPRETATION IN MICROWAVE DIVERSITY IMAGING

IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 1989年第8期37卷 1048-1057页

作者： LI, HJ FARHAT, NH SHEN, YS WERNER, CL UNIV PENN MOORE SCH ELECT ENGNDEPT ELECT ENGNPHILADELPHIAPA 19104 CALTECH JET PROP LABPASADENACA 91109

The authors investigate microwave imaging of metallic objects using a diversity method and interpret and predict the reconstructed image from an approach based on analysis of the scattering mechanism and a back-projection algorithm used in image retrieval. The connection between the various scattering mechanisms and the reconstructed images is discussed, what the images represent is interpreted, and a prediction is made as to what the image will look like over given spectral and angular windows. A brief description is given of the microwave diversity imaging system and the formulation of the microwave diversity imaging based on the physical optics approximation. The scattering mechanism of a complex shaped metallic object is then briefly reviewed and an alternate approach to interpreting the reconstruction image based on the understanding of the scattering mechanism and the reconstruction algorithm is given. Several numerical and experimental examples are included to support this interpretation approach.

关键词： image retrieval MICROWAVE Imaging projection algorithms image reconstruction Angle Image understanding Diversity methods broadcasting Reconstruction algorithm

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Shape control of composite plates by bonded actuators with high performance configuration

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JOURNAL OF REINFORCED PLASTICS AND COMPOSITES 1997年第18期16卷 1692-1710页

作者： Hsu, CY Lin, CC Gaul, L Natl Chung Hsing Univ Inst Appl Math Taichung 402 Taiwan Univ Stuttgart Inst Mech A D-70550 Stuttgart Germany

The electrical fields and configuration parameters such as location, size and thickness of piezoelectric actuators are very important for shape control of structures. By using a performance index, the configuration parameters of actuators and adhesive can be chosen by some rules for improving performance. In this study a procedure combining a finite element model and the gradient projection algorithm is proposed for optimum design of shape control. This finite element model contains the actuator element, the adhesive interface element, and an eight-node isoparametric plate element which is employed for the calculation of plate shape. The gradient projection algorithm is used to choose the optimal values of design variables. Some numerical examples are illustrated and results reveal that the present method is effective and can be applied to the problem of shape control.

关键词： Piezoelectric actuators Element Design plate gradient projection COMPOSITION BOARD Elements design variable PLATES interface element finite element model Element configuration parameter projection algorithms Shape control Piezoelectric actuators configurations actuators

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Application of capacitance tomography to gas-solid flows

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CHEMICAL ENGINEERING SCIENCE 1997年第13期52卷 2099-2110页

作者： Dyakowski, T Edwards, RB Xie, CG Williams, RA UNILEVER RES PORT SUNLIGHT LABS WIRRAL L63 3JWMERSEYSIDEENGLAND SCHLUMBERGER CAMBRIDGE RES LTD CAMBRIDGE CB3 0ELENGLAND UNIV EXETER CAMBORNE SCH MINESPARTICLE & COLLOID ENGN GRPREDRUTH TR15 3SEENGLAND

The fundamental principles of electrical capacitance tomography (ECT) are presented. In particular, the recent developments in the use of a back-projection algorithm applied to solve an inverse problem are discussed. Experimental results obtained for monitoring a pneumatic conveying system and bubbling fluidization are reviewed and revised data are presented. The performance of the ECT is assessed in quantitative and qualitative terms. The use of ECT to provide novel on-line measurement information suitable for modelling or control purposes is illustrated. (C) 1997 Elsevier Science Ltd. All rights reserved.

关键词： System Tomography projection algorithms Electrical capacitance tomography EVAPORATOR CONDENSATE TANK capacitance Inverse method Pneumatic Conveying System

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Linearly constrained global optimization and stochastic differential equations

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JOURNAL OF GLOBAL OPTIMIZATION 2006年第2期36卷 191-217页

作者： Parpas, Panos Rustem, Berc Pistikopoulos, Efstratios N. Univ London Imperial Coll Sci Technol & Med Dept Comp London SW7 2AZ England Univ London Imperial Coll Sci Technol & Med Dept Chem Engn Ctr Proc Syst Engn London SW7 2AZ England

A stochastic algorithm is proposed for the global optimization of nonconvex functions subject to linear constraints. Our method follows the trajectory of an appropriately defined Stochastic Differential Equation (SDE). The feasible set is assumed to be comprised of linear equality constraints, and possibly box constraints. Feasibility of the trajectory is achieved by projecting its dynamics onto the set defined by the linear equality constraints. A barrier term is used for the purpose of forcing the trajectory to stay within the box constraints. Using Laplace's method we give a characterization of a probability measure (Pi) that is defined on the set of global minima of the problem. We then study the transition density associated with the projected diffusion process and show that its weak limit is given by Pi. Numerical experiments using standard test problems from the literature are reported. Our results suggest that the method is robust and applicable to large-scale problems.

关键词： stochastic global optimization simulated annealing stochastic differential equations Fokker-Planck equation Laplace's method projection algorithms

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Ultrasonic Imaging Through Aberrating Layers Using Covariance Matching

IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING

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IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING 2023年 9卷 745-759页

作者： van der Meulen, Pim Coutino, Mario Bosch, Johannes G. Kruizinga, Pieter Leus, Geert Delft Univ Technol Circuits & Syst Grp NL-2628 Delft Netherlands Erasmus Med Ctr Thorax Biomed Engn Dept Cardiol NL-3015 Rotterdam Netherlands Erasmus MC Dept Neurosci NL-3015 Rotterdam Netherlands

We consider the scenario of finding the transfer function of an aberrating layer in front of a receiving ultrasound (US) array, assuming a separate non-aberrated transmit source. We propose a method for blindly estimating this transfer function without exact knowledge of the ultrasound sources or acoustic contrast image, and without directly measuring the transfer function using a separate controlled calibration experiment. Instead, the measurement data of many unknown random images is collected, such as from blood flow, and its second-order statistics are exploited. A measurement model is formulated that explicitly defines the layer's transfer function. A covariance domain problem is then defined to eliminate the image variable, and it is solved for the layer's transfer function using manifold-based optimization. The proposed approach and calibration algorithm are evaluated on a range of challenging and realistic simulations using the k-Wave toolbox. Our results show that, given a sufficiently efficient parameterization of the layer's transfer function, and by jointly estimating the transfer function at multiple frequencies, the proposed algorithm is able to obtain an accurate estimate. Subsequent simulated imaging experiments using the obtained transfer function also show increased imaging performance in various aberrating layers, including a skull layer.

关键词： Aberration correction blind calibration covariance matching projection algorithms ultrasonic imaging

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SUPERLINEAR CONVERGENCE THEOREM IN THE ABSG CLASS OF algorithms FOR NONLINEAR ALGEBRAIC EQUATIONS

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JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS 1988年第1期59卷 39-43页

作者： ABAFFY, J 1.Institute of Mathematics and Computer Science Karl Marx University of Economics Budapest Hungary

In this paper, it is shown that, when two subclasses of algorithms in the ABSg family are applied to a set of nonlinear algebraic equations, then the convergence is superlinear. The conditions for the theorem to be tr... 详细信息

关键词： Nonlinear algebraic equations conjugate direction methods optimization projection algorithms

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A STABLE INDIRECT ADAPTIVE-CONTROL SCHEME FOR 1ST-ORDER PLANTS WITH NO PRIOR KNOWLEDGE ON THE PARAMETERS

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IEEE TRANSACTIONS ON AUTOMATIC CONTROL 1993年第5期38卷 766-771页

作者： GIRI, F IOANNOU, PA AHMEDZAID, F UNIV SO CALIF DEPT ELECT ENGN SYSTLOS ANGELESCA 90089

An indirect adaptive control scheme for a first-order linear time-invariant plant with unknown parameters is presented and analyzed. The scheme requires no a priori knowledge on the sign or bounds of the plant parameters. A discontinuous control law, involving the use of probing,is utilized to avoid any singularities caused by the lack of stabilizabilty of the estimated model. The scheme guarantees signal boundedness and zero residual tracking error.

关键词： Adaptive control Programmable control Parameter estimation State feedback Frequency estimation Parametric statistics Scholarships projection algorithms

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ROBUST ADAPTIVE BEAMFORMING

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IEEE TRANSACTIONS ON ACOUSTICS SPEECH AND SIGNAL PROCESSING 1987年第10期35卷 1365-1376页

作者： COX, H ZESKIND, RM OWEN, MM BBN Laboratories Inc. Arlington VA USA

Adaptive beamforming algorithms can be extremely sensitive to slight errors in array characteristics. Errors which are uncorrelated from sensor to sensor pass through the beamformer like uncorrelated or spatially white noise. Hence, gain against white noise is a measure of robustness. A new algorithm is presented which includes a quadratic inequality constraint on the array gain against uncorrelated noise, while minimizing output power subject to multiple linear equality constraints. It is shown that a simple scaling of the projection of tentative weights, in the subspace orthogonal to the linear constraints, can be used to satisfy the quadratic inequality constraint. Moreover, this scaling is equivalent to a projection onto the quadratic constraint boundary so that the usual favorable properties of projection algorithms apply. This leads to a simple, effective, robust adaptive beamforming algorithm in which all constraints are satisfied exactly at each step and roundoff errors do not accumulate. The algorithm is then extended to the case of a more general quadratic constraint.

关键词： Array signal processing Noise robustness Sensor phenomena and characterization White noise Subspace constraints Adaptive arrays Gain measurement Noise measurement Power generation projection algorithms

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A new spectral variable selection pattern using competitive adaptive reweighted sampling combined with successive projections algorithm

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ANALYST 2014年第19期139卷 4894-4902页

作者： Tang, Guo Huang, Yue Tian, Kuangda Song, Xiangzhong Yan, Hong Hu, Jing Xiong, Yanmei Min, Shungeng China Agr Univ Coll Sci Beijing 100193 Peoples R China Beijing Third Class Supervis Stn Tobacco Beijing 101121 Peoples R China

The competitive adaptive reweighted sampling-successive projections algorithm (CARS-SPA) method was proposed as a novel variable selection approach to process multivariate calibration. The CARS was first used to select informative variables, and then SPA to refine the variables with minimum redundant information. The proposed method was applied to near-infrared (NIR) reflectance data of nicotine in tobacco lamina and NIR transmission data of active ingredient in pesticide formulation. As a result, fewer but more informative variables were selected by CARS-SPA than by direct CARS. In the system of pesticide formulation, a multiple linear regression (MLR) model using variables selected by CARS-SPA provided a better prediction than the full-range partial least-squares (PLS) model, successive projections algorithm (SPA) model and uninformative variables elimination-successive projections algorithm (UVE-SPA) processed model. The variable subsets selected by CARS-SPA included the spectral ranges with sufficient chemical information, whereas the uninformative variables were hardly selected.

关键词： variable selection pattern Cars projection algorithms pesticide formulations Input variables Variable

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CUBIC-SPLINES FOR FILTER DESIGN IN COMPUTED-TOMOGRAPHY

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IEEE TRANSACTIONS ON NUCLEAR SCIENCE 1980年第5期27卷 1368-1374页

作者： HUANG, SC PHELPS, ME HOFFMAN, EJ KUHL, DE UNIV CALIF LOS ANGELES SCH MEDDIV NUCL MEDLOS ANGELESCA 90024

Application of cubic splines is investigated to provide a convenient method of designing flexible reconstruction filters for computed tomography (CT). Cubic splines were found to be compatible with the basic requirements of CT filter's frequency response functions. An interactive computer software system was developed to implement the method of designing CT filters with cubic splines. The system was found to be convenient to use and could provide filters of various characteristics. An example is shown to illustrate the capability of the method in designing filters that can reduce noise levels in emission CT images.

关键词： Filters Computed tomography Image reconstruction Design methodology Biomedical imaging Frequency response Software systems Noise level Back projection algorithms

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