Models and model quality are prime concerns for most design issues in control and systems analysis. The success of a simulation study hinges upon the reliability of the model used. In this contribution we discuss how ...
Models and model quality are prime concerns for most design issues in control and systems analysis. The success of a simulation study hinges upon the reliability of the model used. In this contribution we discuss how to build mathematical models that given certain constraints, are of optimum quality for a prespecified (simulation) application. We then take into account the influence of both bias errors and random errors on the model. It turns our that for a fairly broad class of identification methods in the prediction error family, the optimal choices of design variables can be given in an explicit form.
The paper presents a frequency-domain estimator which can identify both a nominal model of a plant as well as a frequency-domain bounding function on the modeling error associated with this nominal model. This estimat...
详细信息
The paper presents a frequency-domain estimator which can identify both a nominal model of a plant as well as a frequency-domain bounding function on the modeling error associated with this nominal model. This estimator, which we call a robust estimator, can be used in conjunction with a robust control-law redesign algorithm to form a robust adaptive controller.
A layer‐stripping procedure for solving three‐dimensional Schr?dinger equation inverse scattering problems is developed. This method operates by recursively reconstructing the potential from the jump in the scattere...
详细信息
A layer‐stripping procedure for solving three‐dimensional Schr?dinger equation inverse scattering problems is developed. This method operates by recursively reconstructing the potential from the jump in the scattered field at the wave front, and then using the reconstructed potential to propagate the wave front and the scattered field further into the inhomogeneous region. It is thus a generalization of algorithms that have been developed for one‐dimensional inverse scattering problems. Although the procedure has not yet been numerically tested, the corresponding one‐dimensional algorithms have performed well on synthetic data. The procedure is applied to a two‐dimensional inverse seismic problem. Connections between simplifications of this method and Born approximation inverse scattering methods are also noted.
This paper describes a new smoothing algorithm that uses a number of processors to smooth blocks of measurements in parallel with little communication between the processors. This procedure is found to have a total on...
详细信息
This paper describes a new smoothing algorithm that uses a number of processors to smooth blocks of measurements in parallel with little communication between the processors. This procedure is found to have a total on-line computational complexity slightly higher than that of the non-parallel implementations. However, since several processors are used in parallel, the running time of this algorithm is much smaller than that of a single smoother solution.
We consider the behavior of distributed asynchronous routing algorithms for optimizing the flows in a virtual circuit data network, with respect to a given convex cost function. The algorithms operate with minimal syn...
详细信息
We consider the behavior of distributed asynchronous routing algorithms for optimizing the flows in a virtual circuit data network, with respect to a given convex cost function. The algorithms operate with minimal synchronization of computations and information exchange between different processors and consist of gradient projection iterations which compute a target set of flows for each path. Then, the processors try to make the actual flows equal to the target flows, by appropriately assigning paths to incoming, new virtual circuits. We concentrate on the "many small users" case, in which there is (on the average) a very large number of virtual circuits, each one requiring a small communication rate. This note is a followup to our earlier paper [TsBe] and addresses the limiting behavior when the frequency of iteration becomes infinite relative to the frequency of information exchange between nodes.
We consider distributed solution of the classical linear minimum cost network flow problem. We formulate a dual problem which is unconstrained, piecewise linear, and involves a dual variable for each node. We propose ...
详细信息
We consider distributed solution of the classical linear minimum cost network flow problem. We formulate a dual problem which is unconstrained, piecewise linear, and involves a dual variable for each node. We propose a dual algorithm that resembles a Gauss-Seidel relaxation method. At each iteration the dual variable of a single node is changed based on local information from adjacent nodes. In a distributed setting each node can change its variable independently of the variable changes of other nodes. The algorithm is efficient for some classes of problems, notably for the max-flow problem for which it resembles a recent algorithm by Goldberg [11].
In this paper we overview the so-called Linear-Quadratic-Gaussian method with Loop-Tranfer-Recovery (LQG/LTR). Our objective is to provide a pragmatic exposition, with special emphasis on the step-by-step characterist...
详细信息
In this paper we overview the so-called Linear-Quadratic-Gaussian method with Loop-Tranfer-Recovery (LQG/LTR). Our objective is to provide a pragmatic exposition, with special emphasis on the step-by-step characteristics for designing multivariable feedback controlsystems.
We introduce a broad class of algorithms for finding a minimum cost flow in a capacitated network. The algorithms are of the primal-dual type. They maintain primal feasibility with respect to capacity constraints, whi...
详细信息
We introduce a broad class of algorithms for finding a minimum cost flow in a capacitated network. The algorithms are of the primal-dual type. They maintain primal feasibility with respect to capacity constraints, while trying to satisfy the conservation of flow equation at each node by means of a wide variety of procedures based on flow augmentation, price adjustment, and ascent of a dual functional. The manner in which these procedures are combined is flexible thereby allowing the construction of algorithms that can be tailored to the problem at hand for maximum effectiveness. Particular attention is given to methods that incorporate features from classical relaxation procedures. Experimental codes based on these methods outperform by a substantial margin the fastest available primal-dual and primal simplex codes on standard benchmark problems.
A continuous layered medium is probed by sinusoidal spherical waves from a point harmonic source, and the reflection response of the medium is measured. By performing this experiment at two different source frequencie...
详细信息
A continuous layered medium is probed by sinusoidal spherical waves from a point harmonic source, and the reflection response of the medium is measured. By performing this experiment at two different source frequencies, the separate density and sound‐speed profiles ρ(z) and c(z) are recovered. Two experimental configurations are considered: the case in which the inhomogeneous medium is confined between two infinite homogeneous half‐spaces and is probed from the upper half‐space, and the case in which the inhomogeneous medium is bounded above by a free‐surface, at which the source is located. Layer‐stripping fast algorithm solutions to both of these inverse problems are obtained and illustrated with examples. The algorithms are interpreted physically as constructing distributions of image sources that simulate the medium response at each depth.
暂无评论