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941.
Harish C. Bahl Stanley Zionts 《The Journal of the Operational Research Society》1987,38(12):1141-1148
Scheduling the production of several items requires the determination of production quantities in different periods in the presence of resource constraints. Several approximate and heuristic algorithms have been proposed to solve this problem. However, no method for finding an optimal solution has as yet been developed. It is shown that the problem may be solved advantageously using Benders' decomposition. The subproblem in Benders' decomposition is shown to be a transportation problem, and some strategies for solving the master problem are indicated. The paper concludes with a sample problem demonstrating the application of the method. 相似文献
942.
For three‐dimensional flows with one inhomogeneous spatial coordinate and two periodic directions, the Karhunen–Loeve procedure is typically formulated as a spatial eigenvalue problem. This is normally referred to as the direct method (DM). Here we derive an equivalent formulation in which the eigenvalue problem is formulated in the temporal coordinate. It is shown that this so‐called method of snapshots (MOS) has some numerical advantages when compared to the DM. In particular, the MOS can be formulated purely as a matrix composed of scalars, thus avoiding the need to construct a matrix of matrices as in the DM. In addition, the MOS avoids the need for so‐called weight functions, which emerge in the DM as a result of the non‐uniform grid typically employed in the inhomogeneous direction. The avoidance of such weight functions, which may exhibit singular behaviour, guarantees satisfaction of the boundary conditions. The MOS is applied to data sets recently obtained from the direct simulation of turbulence in a channel in which viscoelasticity is imparted to the fluid using a Giesekus model. The analysis reveals a steep drop in the dimensionality of the turbulence as viscoelasticity is increased. This is consistent with the results that have been obtained with other viscoelastic models, thus revealing an essential generic feature of polymer‐induced drag reduced turbulent flows. Published in 2006 by John Wiley & Sons, Ltd. 相似文献
943.
We consider a splitting finite-difference scheme for an initial-boundary value problem for a two-dimensional nonlinear evolutionary
equation. The problem is split into nonlinear and linear parts. The linear part is also split into locally one-dimensional
equations. We prove the convergence and stability of the scheme in L
2 and C norms.
Printed in Lietuvos Matematikos Rinkinys, Vol. 45, No. 3, pp. 413–434, July–September, 2005. 相似文献
944.
945.
Based on the discrete-structural theory of thin plates and shells, a calculation model for thin-walled elements consisting
of a number of rigid anisotropic layers is put forward. It is assumed that the transverse shear and compression stresses are
equal on the interfaces. Elastic slippage is allowed over the interfaces between adjacent layers. The solution to the problem
is obtained in a geometrically nonlinear statement with account of the influence of transverse shear and compression strains.
The stress-strain state of circular two-layer transversely isotropic plates, both without defects and with a local area of
adhesion failure at their center, is investigated numerically and experimentally. It is found that the kinematic and static
contact conditions on the interfaces of layered thin-walled structural members greatly affect the magnitude of stresses and
strains. With the use of three variants of calculation models, in the cases of perfect and weakened contact conditions between
layers, the calculation results for circular plates are compared. It is revealed that the variant suggested in this paper
adequately reflects the behavior of layered thin-walled structural elements under large deformations.
__________
Translated from Mekhanika Kompozitnykh Materialov, Vol. 41, No. 6, pp. 761–772, November–December, 2005. 相似文献
946.
Francesc Carreras M. Dolors Llongueras Antonio Magaña 《Annals of Operations Research》2005,137(1):67-89
A partnership in a cooperative game is a coalition that possesses an internal structure and, simultaneously, behaves as an
individual member. Forming partnerships leads to a modification of the original game which differs from the quotient game
that arises when one or more coalitions are actually formed.
In this paper, the Shapley value is used to discuss the convenience to form either coalitions or partnerships. To this end,
the difference between the additive Shapley value of the partnership in the partnership game and the Shapley alliance value
of the coalition, and also between the corresponding value of the internal and external players, are analysed. Simple games
are especially considered.
Research partially supported by Grant BFM 2003-01314 of the Science and Technology Spanish Ministry and the European Regional
Development Fund. 相似文献
947.
Annegret K. Wagler 《4OR: A Quarterly Journal of Operations Research》2005,3(4):329-336
Shepherd95 proved that the stable set polytopes of near-bipartite graphs are given by constraints associated with the complete
join of antiwebs only. For antiwebs, the facet set reduces to rank constraints associated with single antiwebs by Wagler2004.
We extend this result to a larger graph class, the complements of fuzzy circular interval graphs, recently introduced in ChudnovskySeymour2004.
Received: November 2004 / Revised version: June 2005 相似文献
948.
949.
950.
A. L. Goldenberg V. N. Manuilov M. Yu. Glyavin 《Radiophysics and Quantum Electronics》2005,48(6):461-465
We describe a nonadiabatic electron gun operated in the mode of a currentconfined by spatial charge and intended for producing
helical electron beams for high-power gyroresonantdevices.Results of numerical simulation of electron trajectories and electron-beam
parameters arepresented. It is shown that for a high operating current, the pitch factor and the electronvelocity spread can
be significantly better than in the conventional adiabatic systems.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48,No. 6, pp. 517–522, June 2005 相似文献