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181.
Rudi Penne 《Discrete Mathematics》2010,310(4):966-969
We consider words over a finite alphabet with certain uniqueness properties (a subsequence of length k does not occur more than once) and distance properties (at least j other symbols separate the occurrence of the same symbol). The maximal length of these words is realised by linear de Bruijn sequences with certain forbidden subsequences. We prove the existence of these maximal sequences. 相似文献
182.
This paper considers the problem of locating a single facility in the presence of a line barrier that occurs randomly on a given horizontal route on the plane. The objective is to locate this new facility such that the sum of the expected rectilinear distances from the facility to the demand points in the presence of the probabilistic barrier is minimized. Some properties of the problem are reported, a solution algorithm is provided with an example problem, and some future extensions to the problem are discussed. 相似文献
183.
Michiya Kobayashi Hiroshi Yabe 《Journal of Computational and Applied Mathematics》2010,234(2):375-397
In this paper, we deal with conjugate gradient methods for solving nonlinear least squares problems. Several Newton-like methods have been studied for solving nonlinear least squares problems, which include the Gauss-Newton method, the Levenberg-Marquardt method and the structured quasi-Newton methods. On the other hand, conjugate gradient methods are appealing for general large-scale nonlinear optimization problems. By combining the structured secant condition and the idea of Dai and Liao (2001) [20], the present paper proposes conjugate gradient methods that make use of the structure of the Hessian of the objective function of nonlinear least squares problems. The proposed methods are shown to be globally convergent under some assumptions. Finally, some numerical results are given. 相似文献
184.
Mingquan Zhan 《Discrete Applied Mathematics》2010,158(17):1971-1975
Let G be a graph and let D6(G)={v∈V(G)|dG(v)=6}. In this paper we prove that: (i) If G is a 6-connected claw-free graph and if |D6(G)|≤74 or G[D6(G)] contains at most 8 vertex disjoint K4’s, then G is Hamiltonian; (ii) If G is a 6-connected line graph and if |D6(G)|≤54 or G[D6(G)] contains at most 5 vertex disjoint K4’s, then G is Hamilton-connected. 相似文献
185.
Crossing by lines all edges of a line arrangement 总被引:1,自引:0,他引:1
186.
S. K. Pattanayak 《代数通讯》2013,41(9):3811-3822
For any simple, simply connected algebraic group G of exceptional types (E 6, E 7, E 8, F 4, and G 2) and for any maximal parabolic subgroup P of G, we describe all minimal (with respect to inclusion) Schubert varieties in G/P admitting semistable points for the action of a maximal torus T with respect to an ample line bundle on G/P. This completes the answer to a question proposed in [8] and settled there in the classical case. 相似文献
187.
Katsumi Akahori 《代数通讯》2013,41(10):4283-4289
Let L be a very ample line bundle with h 1(L) ≥2 on a curve of genus g. We prove that L is normally generated if deg(L) ≥2g ? 1 ? 4h 1(L) for large enough genus g. 相似文献
188.
Flavia Bonomo Guillermo Durán Martín D. Safe Annegret K. Wagler 《Discrete Applied Mathematics》2013,161(13-14):1925-1942
A graph is balanced if its clique-matrix contains no edge–vertex incidence matrix of an odd chordless cycle as a submatrix. While a forbidden induced subgraph characterization of balanced graphs is known, there is no such characterization by minimal forbidden induced subgraphs. In this work, we provide minimal forbidden induced subgraph characterizations of balanced graphs restricted to graphs that belong to one of the following graph classes: complements of bipartite graphs, line graphs of multigraphs, and complements of line graphs of multigraphs. These characterizations lead to linear-time recognition algorithms for balanced graphs within the same three graph classes. 相似文献
189.
Jin Ming Luo Jing Qiang Xing-Yong Zhang Jun Tang 《Communications in Nonlinear Science & Numerical Simulation》2013,18(11):3219-3225
The dynamical behavior of spiral waves in a period-2 oscillatory medium is investigated under the influence of an external applied alternating current field. Open and closed transversal line defects which wiggle along the direction parallel to the wave fronts, are generated in the spiral-wave patterns when the stimulus frequency of the electric field is equal to one, three or five times of the local oscillatory frequency in the period-2 state. Their generations are directly related with the change in the spatial wavelength induced by the electric field. These wigglings proliferate along the transverse direction parallel to the wave fronts as the stimulus strength increases, and become denser when the stimulus frequency increases by multiples of the period-2 oscillatory frequency. 相似文献
190.
Celal Yildiz Sinan Gultekin Kerim Guney Seref Sagiroglu 《AEUE-International Journal of Electronics and Communications》2002,56(6):396-406
Neural models for computing the resonant frequency of electrically thin and thick circular microstrip antennas, based on the multilayered perceptrons and the radial basis function networks, are presented. Five learning algorithms, delta-bar-delta, extended delta-bar-delta, quick-propagation, directed random search and genetic algorithms, are used to train the multilayered perceptrons. The radial basis function network is trained according to its learning strategy. The resonant frequency results of neural models are in very good agreement with the experimental results available in the literature. In this paper, the characteristic impedance and the effective permittivity of the asymmetric coplanar waveguide backed with a conductor are also computed by using only one neural model trained by the backpropagation with momentum and the extended delta-bar-delta algorithms. When the performances of neural models are compared with each other, the best results for test are obtained from the multilayered perceptrons trained by the extended delta-bar-delta algorithm. 相似文献