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101.
José Fernando Gonçalves Mauricio G. C. Resende Jorge J. M. Mendes 《Journal of Heuristics》2011,17(5):467-486
This paper presents a biased random-key genetic algorithm for the resource constrained project scheduling problem. The chromosome
representation of the problem is based on random keys. Active schedules are constructed using a priority-rule heuristic in
which the priorities of the activities are defined by the genetic algorithm. A forward-backward improvement procedure is applied
to all solutions. The chromosomes supplied by the genetic algorithm are adjusted to reflect the solutions obtained by the
improvement procedure. The heuristic is tested on a set of standard problems taken from the literature and compared with other
approaches. The computational results validate the effectiveness of the proposed algorithm. 相似文献
102.
103.
François Bentosela Horia D. Cornean Bernard H. Fleury Nicola Marchetti 《Mathematical Methods in the Applied Sciences》2011,34(8):963-976
We develop a deterministic ab initio model for the input–output relationship of a multiple‐input multiple‐output (MIMO) wireless channel, starting from the Maxwell equations combined with Ohm's law. The main technical tools are scattering and geometric perturbation theories. The derived relationship can lead us to a deep understanding of how the propagation conditions and the coupling effects between the elements of multiple‐element arrays affect the properties of an MIMO channel, e.g. its capacity and its number of degrees of freedom. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
104.
We prove that a uniform, rooted unordered binary tree (also known as rooted, binary Pólya tree) with n leaves has the Brownian continuum random tree as its scaling limit for the Gromov‐Hausdorff topology. The limit is thus, up to a constant factor, the same as that of uniform plane trees or labeled trees. Our analysis rests on a combinatorial and probabilistic study of appropriate trimming procedures of trees. © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 38, 467–501, 2011 相似文献
105.
The European Physical Journal A - Efficient neutron transport is a key ingredient to the performance of ultracold neutron (UCN) sources, important to meeting the challenges placed by high precision... 相似文献
106.
107.
Motivated by the superconductivity, we are interested in the fundamental state of the Schorödinger operator with magnetic field. In this paper, we propose a numerical approach based on the finite elements method to determine the bottom of the spectrum of this operator in general domains. We improve the numerical results by using mesh-refinement techniques based on a posteriori error estimators developed elsewhere. We also look at the monotonicity of the bottom of the spectrum in an angular sector according to the angle to complement the theorical study of Bonnaillie (C. R. Acad. Sci. Paris, Ser. I 336 (2) (2003) 135–140). To cite this article: F. Alouges, V. Bonnaillie, C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献
108.
François Quitin Claude Oestges Ali Panahandeh François Horlin Philippe De Doncker 《Physical Communication》2012,5(4):308-316
Polarized multi-antenna systems are an effective solution for reducing inter-antenna spacing while still maintaining low inter-antenna correlation. Traditionally, only dual-polarized antenna systems are used for polarized transceivers. In this paper, tri-polarized antenna systems are investigated. Starting from the polarization mechanisms in the wireless propagation channel, it is shown that dual-polarized MIMO systems show high sensitivity to the transmitter and receiver orientation, which may be very critical in practical applications. Tri-polarized MIMO systems are introduced as a solution to obtain a robust MIMO performances, which are independent of the transmitter and receiver orientation. The performances of dual- and tri-polarized MIMO systems are evaluated on real-world measured channels, and the limits of each of these systems is highlighted. 相似文献
109.
Dopants and defects are important in semiconductor and magnetic devices. Strategies for controlling doping and defects have been the focus of semiconductor physics research during the past decades and remain critical even today. Co-doping is a promising strategy that can be used for effectively tuning the dopant populations, electronic properties, and magnetic properties. It can enhance the solubility of dopants and improve the stability of desired defects. During the past 20 years, significant experimental and theoretical efforts have been devoted to studying the characteristics of co-doping. In this article, we first review the historical development of co-doping. Then, we review a variety of research performed on co-doping, based on the compensating nature of co-dopants. Finally, we review the effects of contamination and surfactants that can explain the general mechanisms of co-doping. 相似文献
110.
Guerrieri F Maccone L Wong FN Shapiro JH Tisa S Zappa F 《Physical review letters》2010,105(16):163602
The Rayleigh diffraction bound sets the minimum separation for two point objects to be distinguishable in a conventional imaging system. We demonstrate sub-Rayleigh resolution by scanning a focused beam--in an arbitrary, object-covering pattern that is unknown to the imager--and using N-photon photodetection implemented with a single-photon avalanche detector array. Experiments show resolution improvement by a factor ~(N-N(max))(?) beyond the Rayleigh bound, where N(max) is the maximum average detected photon number in the image, in good agreement with theory. 相似文献