Now showing items 21-30 of 51
AFS Server Logging
(Center for Information Technology Integration, 1993-11-30)
The AFS servers at the Center for Information Technology Integration have been modified to trace and log file server activity. This report discusses the AFS modifications and the structure of the trace files and data. We ...
Bias-Variance Tradeoffs Analysis Using Uniform CR Bound For a SPECT System
(IEEE, 1993-10-31)
The authors quantify fundamental bias-variance tradeoffs for the image reconstruction problem in radio-pharmaceutical tomography using Cramer-Rao (CR) bound analysis. The image reconstruction problem is very often biased ...
A fast algorithm for extrapolation of discrete-time periodic band-limited signals
(Elsevier, 1993-08)
We present a fast algorithm for exact extrapolation of a discrete-time and periodic band-limited signal from its values in an interval having the same length as the band-width of the signal. Here band-width is the number ...
Tomographic Reconstruction Using Information-Weighted Spline Smoothing
(Springer, 1993)
The conventional method for tomographic image reconstruction, convolution backprojection (CBP), attempts to reduce the effects of measurement noise by radial smoothing with a spatially-invariant filter. Spatially-invariant ...
New Complete-Data Spaces and Faster Algorithms for Penalized- Likelihood Emission Tomography
(IEEE, 1993-10-31)
The classical expectation-maximization (EM) algorithm for image reconstruction suffers from particularly slow convergence when additive background effects such as accidental coincidences and scatter are included. In addition, ...
Search reduction in hierarchical distributed problem solving
(Kluwer Academic Publishers; Springer Science+Business Media, 1993-09)
Knoblock and Korf have determined that abstraction can reduce search at a single agent from exponential to linear complexity (Knoblock 1991; Korf 1987). We extend their results by showing how concurrent problem solving ...
Managing Heterogeneous Distributed Computing Systems: Using Information Repositories
(Center for Information Technology Integration, 1993-12-20)
An integral part of managing heterogeneous distributed computing systems is an information repository. The ultimate goal of our research is to specify a methodology for the design, analysis, and comparison of information ...
Nonmonotonic Cryptographic Protocols
(Center for Information Technology Integration, 1993-11-18)
This paper presents a new method for specifying and analyzing cryptographic protocols. Our method offers several advantages over previous approaches. Our technique is the first to allow reasoning about nonmonotonic protocols. ...
Soliton dragging in discrete and distributed amplifiers
(IOP Publishing Ltd, 1993-10-01)
The authors introduce erbium-doped fibre amplifiers (EDFA) into soliton-dragging logic gates (SDLG) to improve their performance in terms of switching energy, fan-out and tolerance to timing jitter. In particular, they ...
Complete-Data Spaces and Generalized EM Algorithms
(IEEE, 1993-04-27)
Expectation-maximization (EM) algorithms have been applied extensively for computing maximum-likelihood and penalized-likelihood parameter estimates in signal processing applications. Intrinsic to each EM algorithm is a ...