Consideration is given to the problem of robust stability analysis of linear dynamic systems with uncertain physical parameters entering as polynomials in the state equation matrices. A method is proposed giving neces...
详细信息
Consideration is given to the problem of robust stability analysis of linear dynamic systems with uncertain physical parameters entering as polynomials in the state equation matrices. A method is proposed giving necessary and sufficient conditions for computing the uncertain system stability margin in parameter space, which provides a measure of maximal parameter perturbations preserving stability of the perturbed system around a known, stable, nominal system. A globally convergent optimization algorithm that enables solutions to the problem to be obtained is presented. Using the polynomial structure of the problem, the algorithm generates a convergent sequence of interval estimates of the global extremum. These intervals provide a measure of the accuracy of the approximating solution achieved at each step of the iterative procedure. Some numerical examples are reported, showing attractive features of the algorithm from the point of view of computational burden and convergence behavior.
Notation and a theorem are presented which, using a result of B. Chazelle and L.J. Guibas (1985), enable the authors to design an O(n log n) algorithm for reporting all visibility edges of a given n-vertex polygon. Im...
详细信息
Notation and a theorem are presented which, using a result of B. Chazelle and L.J. Guibas (1985), enable the authors to design an O(n log n) algorithm for reporting all visibility edges of a given n-vertex polygon. Improving on this bound to O(n) is presently focused upon. This problem is solved for polygons with at least one given visibility edge. It is assumed that both endpoints of this edge are convex vertices. Subsequently, it is shown how to drop this restriction. The general case of detecting weak edge visibility of an arbitrary simple polygon is dealt with.
The authors propose novel one-pass minimum-variance deconvolution (MVD) algorithms which give the MV estimate, or the approximate MV estimate, of a system's input sequence by means of just one reversed-time filter...
详细信息
The authors propose novel one-pass minimum-variance deconvolution (MVD) algorithms which give the MV estimate, or the approximate MV estimate, of a system's input sequence by means of just one reversed-time filter. They develop the one-pass MVD algorithm in two steps. First, by projecting the input sequence into the space spanned by the future states, they obtain a reversed-time Markov model. Then, by running a Kalman filter for this model, they obtain the MV estimate of the input sequence. In order to avoid the high computational load of the optimal algorithm, a one-pass approximate MVD algorithm which gives almost the same results as the optimal algorithm is developed. Storage requirements and operation counts of J.M. Mendel's (1983) two-pass MVD algorithm and the proposed one-pass approximate MVD algorithm are analyzed for the case of a single-channel system in controllable canonical form. The results are of interest in connection with the seismic deconvolution problem.
An effective quasi-TEM design method for 3-db hybrid couplers using a semi-reentrant coupling section is presented. The analysis is based on the use of the rectangular boundary division method for solving the boundary...
详细信息
An effective quasi-TEM design method for 3-db hybrid couplers using a semi-reentrant coupling section is presented. The analysis is based on the use of the rectangular boundary division method for solving the boundary value problem, including thick-strip conductors in an inhomogeneous medium. A trial design of a microstrip 3-dB coupler using substrates of low dielectric constant has been carried out by adding a sequential optimisation algorithm to the analysis method. Measured parameters of the designed 3-dB hybrid coupler are compared with the theoretical ones.
A general formulation for the mechanics of the grasp with elastic multi-articulated fingers is presented. A procedure utilizing linear programming is given for computing a unique solution for the normal forces as well...
详细信息
A general formulation for the mechanics of the grasp with elastic multi-articulated fingers is presented. A procedure utilizing linear programming is given for computing a unique solution for the normal forces as well as the frictional forces and moments at the contact areas which insures stability of the grasp at the considered configuration. The procedure is particularly useful when the deformation or precision movement of the grasped object is of importance. An efficient optimization algorithm is also given to determine the best grasping configuration for any shape object undergoing any task using end effectors with any number of fingers.
The design discussed is of linear, lumped, time-invariant, multivariable feedback systems, subject to various frequency and time-domain performance specifications. The approach is based on the use of stabilizing contr...
详细信息
The design discussed is of linear, lumped, time-invariant, multivariable feedback systems, subject to various frequency and time-domain performance specifications. The approach is based on the use of stabilizing controller parametrizations which result in the formulation of feedback system design problems as convex, nondifferentiable optimization problems. These problems are solvable by recently developed nondifferentiable optimization algorithms for the constrained minimization of regular, uniformly locally Lipschitz continuous functions in R/sup N/.
Two difficulties arise in the use of optimization algorithms based on an exact penalty function and quadratic subproblems: the possible inconsistency of the quadratic programs and the admissibility of the unit stepsiz...
详细信息
Two difficulties arise in the use of optimization algorithms based on an exact penalty function and quadratic subproblems: the possible inconsistency of the quadratic programs and the admissibility of the unit stepsize after a finite number of iterations. In this paper, assuming that no inequality constraint is present, the author devises an algorithm, using a nondifferentiable augmented Lagrangian, that, under convenient hypotheses, solves both problems.
A capacitor sizing problem for capacitors placed on a radial distribution system is formulated as a nonlinear programming problem, and a solution algorithm is developed. The object is to find the optimal size of the c...
详细信息
A capacitor sizing problem for capacitors placed on a radial distribution system is formulated as a nonlinear programming problem, and a solution algorithm is developed. The object is to find the optimal size of the capacitors so that the power losses will be minimized for a given load profile while considering the cost of the capacitors. The formulation also incorporates the AC power flow model for the system and the voltage constraints. The solution algorithm developed for the capacitor sizing problem is based on a Phase I-Phase II feasible directions approach. Novel power flow equations and a solution method, called DistFlow, for radial distribution systems are introduced. The method is computationally efficient and numerically robust, especially for distribution systems with large r/x ratio branches. DistFlow is used repeatedly as a subroutine in the optimization algorithm for the capacitor sizing problem. The test results for the algorithm indicate that the method is computationally efficient and has good convergence characteristics.
For pt.I see ibid., vol.36, no.9, p.935-45 (1989). A discrete-time, lumped-parameter mathematical model of the human cardiopulmonary circulation as it appears during a first-transit radionuclide study was described in...
详细信息
For pt.I see ibid., vol.36, no.9, p.935-45 (1989). A discrete-time, lumped-parameter mathematical model of the human cardiopulmonary circulation as it appears during a first-transit radionuclide study was described in pt.I. An optimal fitting process is used to match curves obtained from the model to curves obtained from first transit studies in order to estimate the parameters of the subject's heart. The development of the optimization technique is described. The results of testing the effects of overlapping compartments and errors in delay estimates are presented. A parameter determination analysis is performed by applying the optimization algorithm to simulated data. This analysis technique provides a method of estimating many parameters of heart function using a single, simple, rapid procedure.
An automatic algorithm has been developed for high-speed detection of cavity boundaries in sequential 2-D echocardiograms using an optimization algorithm called simulated annealing (SA). The algorithm has three stages...
详细信息
An automatic algorithm has been developed for high-speed detection of cavity boundaries in sequential 2-D echocardiograms using an optimization algorithm called simulated annealing (SA). The algorithm has three stages. (1) A predetermined window of size n*m is decimated to size n'*m' after low-pass filtering. (2) An iterative radial gradient algorithm is employed to determine the center of gravity (CG) of the cavity. (3) 64 radii which originate from the CG defined in stage 2 are bounded by the high-probability region. Each bounded radius is defined as a link in a 1-D, 64-member cyclic Markov random field. This algorithm is unique in that it compounds spatial and temporal information along with a physical model in its decision rule, whereas most other algorithms base their decisions on spatial data alone. This is the first implementation of a relaxation algorithm for edge detection in echocardiograms. Results attained using this algorithm on real data have been highly encouraging.
暂无评论