Custom Integrated Circuits

Contains reports on seven research projects.U.S. Air Force - Office of Scientific Research (Contract F49620-84-C-0004)National Science Foundation (Grant ECS81-18160)Defense Advanced Research Projects Agency (Contract NOO14-80-C-0622)National Science Foundation (Grant ECS83-10941

Signal Delay in General RC Networks with Application to Timing Simulation of Digital Integrated Circuits

Modeling digital MOS circuits by RC networks has become a well accepted practice for estimating delays. In 1981, Penfield and Rubinstein proposed a method to bound the waveforms of nodes in an RC tree network. In this paper, a single value of delay is derived for any node in a general RC network. The effects of parallel connections and stored charges are properly taken into consideration. The algorithms can be used either as a stand-alone simulator, or as a front end for producing initial waveforms for waveform-relaxation based circuit simulators. An experimental simulator called SDS (Signal Delay Simulator) has been developed. For all the examples tested so far, this simulator runs two to three orders of magnitude faster than SPICE, and detects all transitions and glitches at approximately the correct time

Custom Integrated Circuits

Contains reports on four research projects.U.S. Air Force - Office of Scientific Research (Contract F49620-81-C-0054)U.S. Air Force - Office of Scientific Research (Contract F49620-84-C-0004)National Science Foundation (Grant ECS81-18160)National Science Foundation (Grant ECS83-10941

Custom Integrated Circuits

Contains reports on six research projects.U.S. Air Force - Office of Scientific Research (Contract F49620-84-C-0004)Analog Devices, Inc.Defense Advanced Research Projects Agency (Contract N00014-80-C-0622)National Science Foundation (Grant ECS83-10941

Custom Integrated Circuits

Contains reports on twelve research projects.Analog Devices, Inc.International Business Machines, Inc.Joint Services Electronics Program (Contract DAAL03-86-K-0002)Joint Services Electronics Program (Contract DAAL03-89-C-0001)U.S. Air Force - Office of Scientific Research (Grant AFOSR 86-0164)Rockwell International CorporationOKI Semiconductor, Inc.U.S. Navy - Office of Naval Research (Contract N00014-81-K-0742)Charles Stark Draper LaboratoryNational Science Foundation (Grant MIP 84-07285)National Science Foundation (Grant MIP 87-14969)Battelle LaboratoriesNational Science Foundation (Grant MIP 88-14612)DuPont CorporationDefense Advanced Research Projects Agency/U.S. Navy - Office of Naval Research (Contract N00014-87-K-0825)American Telephone and TelegraphDigital Equipment CorporationNational Science Foundation (Grant MIP-88-58764

Pseudospectra of waveform relaxation operators

Abstract--The performance of the waveform relaxation method for solving systems of ODEs depends largely on the choices that are made for splitting, size of time window, and preconditioning. Although it is known that superlinear convergence is obtained on finite time windows, the convergence may be slow in the first few iterations. We propose the use of pseudcepectra to analyze the convergence ratio of the first few iterations when waveform relaxation is applied to linear systems of ODEs. Through pseudcepectral radii, we can examine the effect of preconditioning and overlapping on the rate of convergence. We may also use this to estimate a suitable size of the time window. Numerical experiments performed on a system of ODEs arising from the discretization of an advection-diffusion equation confirm the validity of the obtained estimates. (~) 1998 Elsevier Science Ltd. All rights reserved

A note on windowing for the waveform relaxation

The technique of windowing has been often used in the implementation of the waveform relaxations for solving ODE's or time dependent PDE's. Its efficiency depends upon problem stiffness and operator splitting. Using model problems, the estimates for window length and convergence rate are derived. The electiveness of windowing is then investigated for non-stiff and stiff cases respectively. lt concludes that for the former, windowing is highly recommended when a large discrepancy exists between the convergence rate on a time interval and the ones on its subintervals. For the latter, windowing does not provide any computational advantage if machine features are disregarded. The discussion is supported by experimental results

Uncertainty Quantification of the Responses of Transient Electromagnetic Disturbance Coupling to Transmission Lines Based on Stochastic Models

L'abstract è presente nell'allegato / the abstract is in the attachmen