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51.
Omar Ramadan 《International Journal of Infrared and Millimeter Waves》2005,26(12):1757-1770
Unconditionally stable formulations of the anisotropic perfectly matched layer (APML) are presented for truncating double
negative (DNG) meta-material finite difference time domain (FDTD) grids. In the proposed formulations, the Z-transform theory
is employed in the alternating direction implicit FDTD (ADI-FDTD) scheme to obtain update equations for the field components
in the DNG meta-material domains. Numerical examples carried out in one dimensional Lorentzian type DNG meta-material domains
are included to show the validity of the proposed formulations. 相似文献
52.
Multiple UAVs path planning algorithms: a comparative study 总被引:1,自引:0,他引:1
B. Moses Sathyaraj L. C. Jain A. Finn S. Drake 《Fuzzy Optimization and Decision Making》2008,7(3):257-267
Unmanned aerial vehicles (UAVs) are used in team for detecting targets and keeping them in its sensor range. There are various
algorithms available for searching and monitoring targets. The complexity of the search algorithm increases if the number
of nodes is increased. This paper focuses on multi UAVs path planning and Path Finding algorithms. Number of Path Finding
and Search algorithms was applied to various environments, and their performance compared. The number of searches and also
the computation time increases as the number of nodes increases. The various algorithms studied are Dijkstra’s algorithm,
Bellman Ford’s algorithm, Floyd-Warshall’s algorithm and the AStar algorithm. These search algorithms were compared. The results
show that the AStar algorithm performed better than the other search algorithms. These path finding algorithms were compared
so that a path for communication can be established and monitored. 相似文献
53.
As a leading statistician in extreme value theory, Professor Laurens de Haan has made significant contribution in both probability
and statistics of extremes. In honor of his 70th birthday, we review testing issues in extremes, which include research done
by Professor Laurens de Haan and many others. In comparison with statistical estimation in extremes, research on testing has
received less attention. So we also point out some practical questions in this direction.
相似文献
54.
55.
Javier Barajas 《Discrete Mathematics》2008,308(8):1355-1365
The distance graph G(D) has the set of integers as vertices and two vertices are adjacent in G(D) if their difference is contained in the set D⊂Z. A conjecture of Zhu states that if the chromatic number of G(D) achieves its maximum value |D|+1 then the graph has a triangle. The conjecture is proven to be true if |D|?3. We prove that the chromatic number of a distance graph with D={a,b,c,d} is five only if either D={1,2,3,4k} or D={a,b,a+b,b-a}. This confirms a stronger version of Zhu's conjecture for |D|=4, namely, if the chromatic number achieves its maximum value then the graph contains K4. 相似文献
56.
A subset X in the Euclidean plane is called a k-distance set if there are exactly k distances between two distinct points in X. We denote the largest possible cardinality of k-distance sets by g(k). Erdős and Fishburn proved that g(5)=12 and also conjectured that 12-point five-distance sets are unique up to similar transformations. We classify 8-point four-distance sets and prove the uniqueness of the 12-point five-distance sets given in their paper. We also introduce diameter graphs of planar sets and characterize these graphs. 相似文献
57.
This paper deals with the shape reconstruction of a viscous incompressible fluid driven by the Stokes flow. For the approximate solution of the ill-posed and nonlinear problem we propose a regularized Newton method. A theoretical foundation for the Newton method is given by establishing the differentiability of the initial boundary value problem with respect to the interior boundary curve in the sense of a domain derivative. The numerical examples show that our theory is useful for practical purpose and the proposed algorithm is feasible. 相似文献
58.
Spiess HW 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,(2):326-328
The development of four-pulse DEER as described, which has been published in the Journal of Magnetic Resonance more than 10 years ago. The corresponding paper is an example where a slight advance, such as adding a refocusing pulse, which in retrospect looks so simple, can have a remarkable impact on an entire field of science. In our case it offered a simple way to exact measurements of distances between defined species in the nanometer range. The current applications are mainly in determining structures of proteins and nucleic acids. 相似文献
59.
P. KleinR. Varga G.A. Badini-ConfalonieriM. Vazquez 《Journal of magnetism and magnetic materials》2011,323(24):3265-3270
We have studied the effect of thermal treatment on the magnetic domain structure and magnetic reversal process of amorphous and nanocrystalline Fe40Co38Mo4B18 microwires. The domain structure and the magnetization reversal of amorphous FeCoMoB microwires reflect the complex stress distribution introduced by the glass coating. Hence, the thickness of radial domain structure decreases with temperature and the temperature dependence of the switching field presents a discontinuous behavior. After nanocrystallization, the domain structure of FeCoMoB microwire is almost constant within the temperature range 10-400 K and the switching field decreases almost linearly with temperature mostly because of the decrease of saturation magnetization. 相似文献
60.
We consider the dynamics of the domain-wall kink soliton, in particular we study the zero mode of translation. In the infinitely-thin kink limit, we show that the zero mode is almost completely frozen out, the only remnant being a dynamically constrained four-dimensional mode of a single but arbitrary frequency. In relation to this result, we show that the usual mode expansion for dealing with zero modes - implicit collective coordinates - is not in fact a completely general expansion, and that one must use instead a traditional generalised Fourier analysis. 相似文献