290 research outputs found
Maximum Entropy Reconstruction Of Moment Coded Images
The maximum entropy principle (MEP) is applied to the problem of reconstructing an image from knowledge of a finite set of its moments. This new approach is compared to the existing method of moments approach and is shown to have a clear edge in performance in all of the applications attempted. Compression ratios more than twice as high as those previously achieved are possible with the new MEP method
Exact solution of the six-vertex model with domain wall boundary conditions. Antiferroelectric phase
We obtain the large asymptotics of the partition function of the
six-vertex model with domain wall boundary conditions in the antiferroelectric
phase region, with the weights a=\sinh(\ga-t), b=\sinh(\ga+t), c=\sinh(2\ga),
|t|<\ga. We prove the conjecture of Zinn-Justin, that as ,
Z_n=C\th_4(n\om) F^{n^2}[1+O(n^{-1})], where \om and are given by
explicit expressions in \ga and , and is the Jacobi theta
function. The proof is based on the Riemann-Hilbert approach to the large
asymptotic expansion of the underlying discrete orthogonal polynomials and on
the Deift-Zhou nonlinear steepest descent method.Comment: 69 pages, 10 figure
ON THE USE OF NATURAL-MODE BASIS FUNCTIONS FOR ELECTROMAGNETIC ANALYSIS OF ARBITRARY CONDUCTING SURFACES
The natural modes defined in the singularity expansion method (SEM) are used as basis functions for the frequency- and time-domain current responses of arbitrary perfect electrically conducting (PEC) surfaces in this work. First, a method of determining the natural frequencies and corresponding modes which employs the electric field integral equation is presented. These quantities are then calculated for several geometries and the currents induced due to an incident plane wave in the frequency and time domains are approximated by a weighted sum of the natural modes. Additionally, the modal weights prescribed by SEM are compared to a set of weights obtained through a least-squares (LS) fit. Lastly, the ability of natural modes to represent the currents due to a delta-gap antenna feed is considered
- …