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161.
162.
It has been recently shown that large growth factors might occur in Gaussian Elimination with Partial Pivoting (GEPP) also when solving some plausibly natural systems. In this note we argue that this potential problem could be easily solved, with much smaller risk of failure, by very small (and low cost) modifications of the basic algorithm, thus confirming its inherent robustness. To this end, we first propose an informal model with the goal of providing further support to the comprehension of the stability properties of GEPP. We then report the results of numerical experiments that confirm the viewpoint embedded in the model. Basing on the previous observations, we finally propose a simple scheme that could be turned into (even more) accurate software for the solution of linear systems. 相似文献
163.
Valerio Annovazzi-Lodi Giuseppe Aromataris Mauro Benedetti Michael Hamacher Sabina Merlo Valeria Vercesi 《Optical and Quantum Electronics》2010,42(3):143-156
In this paper, we numerically evaluate private data transmission using a three-laser scheme, consisting of a pair of twin
semiconductor lasers, driven to chaos by delayed optical feedback in a short cavity, and optically injected by a third chaotic
laser which forces them to synchronize. This laser is selected with different internal parameters with respect to the twin
pair, so that the emissions of the synchronized, matched lasers, are highly correlated, whereas their correlation with the
driver is low. The digital message modulates the emission of the transmitter, as in a standard Chaos Modulation scheme. Message
recovery is then obtained by subtracting, from the transmitted chaos-masked message, the chaos, locally generated by the synchronized
receiver laser. Simulations have been performed with the Lang-Kobayashi model, and, in view of application to private transmission,
we have investigated the effect of the parameter mismatch, between transmitter and receiver, on message recovery. A preliminary
experimental evaluation has been also performed using specially designed InP integrated modules. 相似文献
164.
Mauro F.A. Adamo Simone Bruschi Surisetti Suresh Linda Piras 《Tetrahedron letters》2008,49(52):7406-7409
Herein we describe the preparation of a novel class of isoxazolyl aziridines. The products were obtained exclusively as cis diastereoisomers. 相似文献
165.
Maiara Oliveira Salles Ana Paula Ruas de Souza Juliana Naozuka Pedro Vitoriano de Oliveira Mauro Bertotti 《Electroanalysis》2009,21(12):1439-1442
Electrodeposition of bismuth on gold microelectrodes for determination of Pb(II) by square wave anodic stripping voltammetry (SWASV) was accomplished by an in situ procedure in alkaline solution. A linear calibration plot for Pb(II) in the concentration range 40 to 6700 nmol L?1 (r=0.998) was obtained, the detection limit was found to be 12.5 nmol L?1 (S/N=3) and the relative standard deviation in solutions containing 1 μmol L?1 Pb(II) was 4% (n=12). The analytical performance of the proposed sensor was tested by measuring the Pb(II) concentration in a wine sample. The result was in good agreement with the one obtained by GFAAS. 相似文献
166.
Generation of ammonia via thermal decomposition of formamide was studied under microwave conditions to provide an efficient tool for the synthesis of nitrogen-containing heterocycles. Quinazolin-4-ones, which are known as building blocks for molecules with pharmaceutical interest, were chosen as examples. Our work confirms that reactants may have different behaviours under microwaves, depending on power input, reached temperature and pressure in the vials. Full control and fine tuning of these parameters are achievable using modern microwave technology. 相似文献
167.
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169.
Barbara Panicucci Massimo Pappalardo Mauro Passacantando 《Computational Optimization and Applications》2009,43(2):197-211
We propose a descent method via gap functions for solving nonsmooth variational inequalities with a locally Lipschitz operator.
Assuming monotone operator (not necessarily strongly monotone) and bounded domain, we show that the method with an Armijo-type
line search is globally convergent. Finally, we report some numerical experiments.
This work has been supported by the National Research Program PRIN/2005017083 “Innovative Problems and Methods in Nonlinear
Optimization”. 相似文献
170.