32,852 research outputs found
Row-Action Methods for Compressed Sensing
Compressed Sensing uses a small number of random, linear measurements to acquire a sparse signal. Nonlinear algorithms, such as l1minimization, are used to reconstruct the signal from the measured data. This paper proposes row-action methods as a computational approach to solving the l1optimization problem. This paper presents a specific row-action method and provides extensive empirical evidence that it is an effective technique for signal reconstruction. This approach offers several advantages over interior-point methods, including minimal storage and computational requirements, scalability, and robustness
A Robust Solution Procedure for Hyperelastic Solids with Large Boundary Deformation
Compressible Mooney-Rivlin theory has been used to model hyperelastic solids,
such as rubber and porous polymers, and more recently for the modeling of soft
tissues for biomedical tissues, undergoing large elastic deformations. We
propose a solution procedure for Lagrangian finite element discretization of a
static nonlinear compressible Mooney-Rivlin hyperelastic solid. We consider the
case in which the boundary condition is a large prescribed deformation, so that
mesh tangling becomes an obstacle for straightforward algorithms. Our solution
procedure involves a largely geometric procedure to untangle the mesh: solution
of a sequence of linear systems to obtain initial guesses for interior nodal
positions for which no element is inverted. After the mesh is untangled, we
take Newton iterations to converge to a mechanical equilibrium. The Newton
iterations are safeguarded by a line search similar to one used in
optimization. Our computational results indicate that the algorithm is up to 70
times faster than a straightforward Newton continuation procedure and is also
more robust (i.e., able to tolerate much larger deformations). For a few
extremely large deformations, the deformed mesh could only be computed through
the use of an expensive Newton continuation method while using a tight
convergence tolerance and taking very small steps.Comment: Revision of earlier version of paper. Submitted for publication in
Engineering with Computers on 9 September 2010. Accepted for publication on
20 May 2011. Published online 11 June 2011. The final publication is
available at http://www.springerlink.co
New Method of Measuring TCP Performance of IP Network using Bio-computing
The measurement of performance of Internet Protocol IP network can be done by
Transmission Control Protocol TCP because it guarantees send data from one end
of the connection actually gets to the other end and in the same order it was
send, otherwise an error is reported. There are several methods to measure the
performance of TCP among these methods genetic algorithms, neural network, data
mining etc, all these methods have weakness and can't reach to correct measure
of TCP performance. This paper proposed a new method of measuring TCP
performance for real time IP network using Biocomputing, especially molecular
calculation because it provides wisdom results and it can exploit all
facilities of phylogentic analysis. Applying the new method at real time on
Biological Kurdish Messenger BIOKM model designed to measure the TCP
performance in two types of protocols File Transfer Protocol FTP and Internet
Relay Chat Daemon IRCD. This application gives very close result of TCP
performance comparing with TCP performance which obtains from Little's law
using same model (BIOKM), i.e. the different percentage of utilization (Busy or
traffic industry) and the idle time which are obtained from a new method base
on Bio-computing comparing with Little's law was (nearly) 0.13%.
KEYWORDS Bio-computing, TCP performance, Phylogenetic tree, Hybridized Model
(Normalized), FTP, IRCDComment: 17 Pages,10 Figures,5 Table
- …