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排序方式: 共有821条查询结果,搜索用时 234 毫秒
31.
In this Letter, a novel method is developed for generating grid multi-scroll chaotic attractors using switching piecewise linear controller. First, a third-order linear system is designed to ensure that its unique equilibrium point belongs to a saddle-focus type with index 2 and the corresponding eigenvalues satisfy Shilnikov conditions. Then, by three different types of switching control strategies, the equilibrium point can be extended along both xy plane and z axis direction, so as to generate grid multi-scroll chaotic attractors. The dynamical behaviors are further analyzed. Moreover, an improved module-based circuit is designed for realizing 5×3 and 4×4 grid scroll chaotic attractors, and the experimental results are also obtained, which is consistent with the numerical simulations. 相似文献
32.
Malcolm Greig 《Designs, Codes and Cryptography》2002,27(1-2):25-47
Batten and Beutelspacher have characterized Finite Linear Spaces with lines of size n,n + 1 and n + 2, and with v (n + 1)2for n 22, and some of the cases for smaller n. In this article, using the structuredapproach we presented in our earlier article [8], we complete this characterization for smalln. 相似文献
33.
Consider a closed Jackson type network in which each queue has a single exponential server. Assume that N customers are moving among k queues. We establish simple closed form bounds on the network throughput (both lower and upper), which are sharper than those that are currently available. Numerical evaluation indicates that the improvements are significant. 相似文献
34.
35.
Several new constructions for difference matrices are given. One classof constructions uses pairwise balanced designs to develop newdifference matrices over the additive group of GF (q). A second class of constructions gives difference matrices overgroups whose orders are not (necessarily) prime powers. 相似文献
36.
The criterion robustness of the standard likelihood ratio test (LRT) under the multivariate normal regression model and also the inference robustness of the same test under the univariate set up are established for certain nonnormal distributions of errors. Restricting attention to the normal distribution of errors in the context of univariate regression models, conditions on the design matrix are established under which the usual LRT of a linear hypothesis (under homoscedasticity of errors) remains valid if the errors have an intraclass covariance structure. The conditions hold in the case of some standard designs. The relevance of C. R. Rao's (1967 In Proceedings Fifth Berkeley Symposium on Math. Stat. and Prob., Vol. 1, pp. 355–372) and G. Zyskind's (1967, Ann. Math. Statist.38 1092–1110) conditions in this context is discussed. 相似文献
37.
Oseen’ approximations are used to study the slow motion of a viscous, incompressible, electrically conducting fluid past a
circular cylinder in the presence of a uniform aligned magnetic field. Using series truncation method, the analytical solutions
for the first three terms in the Fourier sine series expansion of the stream function are obtained. Numerical values of the
tangential drag for different values of magnetic interaction parameter and viscous Reynolds number are calculated. 相似文献
38.
Khaneja N Reiss T Kehlet C Schulte-Herbrüggen T Glaser SJ 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2005,172(2):296-305
In this paper, we introduce optimal control algorithm for the design of pulse sequences in NMR spectroscopy. This methodology is used for designing pulse sequences that maximize the coherence transfer between coupled spins in a given specified time, minimize the relaxation effects in a given coherence transfer step or minimize the time required to produce a given unitary propagator, as desired. The application of these pulse engineering methods to design pulse sequences that are robust to experimentally important parameter variations, such as chemical shift dispersion or radiofrequency (rf) variations due to imperfections such as rf inhomogeneity is also explained. 相似文献
39.
A directed balanced incomplete block design (or D
B(k,;v)) (X,) is called self-converse if there is an isomorphic mapping f from (X,) to (X,–1), where –1={B
–1:B} and B
–1=(x
k
,x
k
–1,,x
2,x
1) for B=(x
1,x
2,,x
k
–1,x
k
). In this paper, we give the existence spectrum for self-converse D
B(4,1;v).
AMS Classification:05BResearch supported in part by NSFC Grant 10071002 and SRFDP under No. 20010004001 相似文献
40.
Asymptotic approach to the truncated cosh-Gaussian beams 总被引:3,自引:0,他引:3
The propagation behavior and M
2-factor of truncated cosh-Gaussian (ChG) beams are studied by using the asymptotic approach. Detailed numerical results are given to illustrate the dependence of M
2-factor on the beam decentered parameter , truncation fraction p and power fraction f. Our results are self-consistent and reduce to those of Pare and Belanger [Opt. Commun.
123, p. 679 (1996a); Proc. SPIE
2870, p. 104 (1996b)]. The advantage of the approach is shown, and the problems introduced by the hard-aperture diffraction and the approach used are discussed. 相似文献