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951.
Rahul Bhatt Sanjay K. Mishra D. Mohan A.K. Gupta 《Optics and Lasers in Engineering》2008,46(6):428-439
A fast holographic wavefront sensor is proposed using a computer-generated hologram (CGH). This CGH is a multiplexed hologram of different Zernike mode–amplitude combinations, and is designed in such a manner as to get the corresponding spots on the detector according to the presence and strength of a particular aberration. Interference between the aberrated wavefront (with a single mode–amplitude combination) and the Fourier transform of an image with single bright pixel (defined as dot image) is numerically calculated for one hologram. Different mode–amplitude combination and corresponding different positions of bright pixels (dots) are taken to compute various holograms and then all the holograms are multiplexed to get the final hologram. When the aberrated wavefront with a particular mode–amplitude combination is incident onto the multiplexed hologram, the corresponding dot is generated in the Fourier plane. A lens performs the Fourier transform in optical domain and provides the instant detection of amplitude of the respective Zernike mode. The main advantage of the scheme is to avoid the need of any computations, which makes it really fast. The simulation results are presented with the cross-talk analysis for few Zernike terms. 相似文献
952.
设E=■或■,■(x)∈L~2(R~2)且■_(jk)(x)=2■(E~jx-k),其中j∈Z,k∈Z~2.若{■_(jk)|jJ∈Z,k∈Z~2}构成L~2(R~2)的紧框架,则称■(x)为E-紧框架小波.本文给出E-紧框架小波是MRA E-紧框架小波的一个充要条件,即E紧框架小波■来自多尺度分析当且仅当线性空间F_■(ξ)的维数为0或1,其中F_■(ξ)=■(ξ)|j■1},■_j(ξ)={■((E~T)~j(ξ+2kπ))}_(k∈EZ~2,j■1。 相似文献
953.
Passengers travelling in public transportation networks often have to use different lines to cover the trip from their origin to the desired destination. As a consequence, the reliability of connections between vehicles is a key issue for the attractiveness of the intermodal transportation network and it is strongly affected by some unpredictable events like breakdowns or vehicle delays. In such cases, a decision is required to determine if the connected vehicles should wait for the delayed ones or keep their schedule. The delay management problem (DMP) consists in defining the wait/depart policy which minimizes the total delay on the network. In this work, we present two equivalent mixed integer linear programming models for the DMP with a single initial delay, able to reduce the number of variables with respect to the formulations proposed by the literature. The two models are solved by a branch and cut procedure and by a constraint generation approach respectively, and preliminary computational results are presented. 相似文献
954.
在曲线的多分辨率分析基础上,构造了一种新的非线性三分多分辨率算法.并研究这个正则三分多分辨率算法的收敛性和稳定性,进一步,证明了小波参数的收敛性精密地依靠这个基本的多分辨率细分算法的收敛性. 相似文献
955.
非线性单模光纤中源啁啾孤子相互作用 总被引:8,自引:0,他引:8
本文采用分步傅氏变换法对非线性单模光纤中源啁啾孤子相互作用进行了详细的数值研究.所得结果揭示了先源啁啾对孤子相互作用影响的本质,为设计光源啁啾情况下的孤子传转系统提供了依据. 相似文献
956.
Zhang Guangzhao Zhou Guangqun 《International Journal of Infrared and Millimeter Waves》1989,10(2):257-267
The Marple algorthm for the autoregressive spectral estimates has been applied to the SMMW Fourier transform spectrum analysis. The experimental results have shown that this method yields AR spectra with three times higher resolution than the FFT method does. The improvements obtained from the Marple algorithm over the maximum entropy algorithm include higher resolution, less bias in the spectral peak frequency estimation and absence of observed spectral line splitting. The effects of the structure of the spectral lines and the noise on the resolution are discussed.Projects supported by National Natural Science Foundation of China 相似文献
957.
In this paper, we study a second order variational problem for locally convex hypersurfaces, which is the affine invariant analogue of the classical Plateau problem for minimal surfaces. We prove existence, regularity and uniqueness results for hypersurfaces maximizing affine area under appropriate boundary conditions.
958.
利用小波分析预测方法对金融数据—股票收盘价这一典型的非平稳时间序列进行预测.使用M a llat小波分解算法对数据进行分解,对分解后的数据进行平滑处理,然后再进行重构,而重构之后的数据就成为近似意义的平稳时间序列,这样就得到了原始数据的近似信号,再应用传统时间序列预测方法对重构后的数据进行预测,将预测结果与实际值,以及和传统预测方法预测结果比较,小波分析方法预测效果更为理想. 相似文献
959.
This paper describes the formulation of a nonlinear mixed integer programming model for a large-scale product development
and distribution problem and the design and computational implementation of a special purpose algorithm to solve the model.
The results described demonstrate that integrating the art of modeling with the sciences of solution methodology and computer
implementation provides a powerful approach for attacking difficult problems. The efforts described here were successful because
they capitalized on the wealth of existing modeling technology and algorithm technology, the availability of efficient and
reliable optimization, matrix generation and graphics software, and the speed of large-scale computer hardware. The model
permitted the combined use of decomposition, general linear programming and network optimization within a branch and bound
algorithm to overcome mathematical complexity. The computer system reliably found solutions with considerably better objective
function values 30 to 50 times faster than had been achieved using general purpose optimization software alone. Throughout
twenty months of daily use, the system was credited with providing insights and suggesting strategies that led to very large
dollar savings.
This research was supported in part by the Office of Naval Research Contract N00014-78-C-0222, by the Center for Business
Decision Analysis*, by the University of Texas at Austin, and by the David Bruton, Jr., Centennial Chair in Business Decision
Support Systems. Reproduction in whole or in part is permitted for any purpose of the U.S. Government.
Center for Business Decision Analysis, Graduate School of Business — GSB 3.126, University of Texas, Austin, Texas 78712,
USA. 相似文献
960.
This article presents solutions for the transient heat and moisture transport due to both disk heat source and cylindrical
heat source buried in an unsaturated half space. The solutions are presented in Hankel–Laplace transform domain and in dimensionless
style. Coupled effect of thermally driven moisture transport is especially investigated because of its importance to alter
the flow field in low-permeability medium. Parametric study has been performed to assess the effects of five independent dimensionless
parameters on flow field. The stability and accuracy of the present solutions are demonstrated from the comparison between
the results obtained from these solutions and those by using a well-established finite element code CODE_BRIGHT. Despite the
simplified assumptions required in order to obtain analytical solutions in Hankel–Laplace transform domain, the results incorporate
the main mechanisms involved in the coupled thermo-hydraulic (T-H) problem, and they may be eventually used for validation
purposes. 相似文献