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11.
In this paper, we study a non-capacitated Vehicle Routing Problem (VRP) where not necessarily all clients need to be visited and the goal is to minimize the length of the longest vehicle route. An Integer Programming Formulation, a Branch-and-cut (BC) method and a Local Branching (LB) framework that uses BC as the inner solver are presented. Sharper upper bounds are obtained by LB, when the same time limit was imposed on the execution times of both approaches. Our results also suggest that the min-max nature of the objective function combined with the fact that not all vertices need to be visited make such problem very difficult to solve. 相似文献
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An experimentally feasible protocol for realizing dense coding by using a class of W-state in cavity quantum electrodynamics (QED) is proposed in this paper. The prominent advantage of our scheme is that the successful probability of the dense coding with a W-class state can reach 1. In addition, the scheme can be implemented by the present cavity QED techniques. 相似文献
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Scaling of submonolayer island growth with reversible adatom exchange in surfactant-mediated epitaxy
Surfactant-mediated epitaxial growth is studied with a realistic model, which includes three main kinetic processes: diffusion of adatoms on the surfactant terrace, exchange of adatoms with their underneath surfactant atoms, and reexchange in which an exchanged adatom resurfaces to the top of the surfactant layer. The scaling behavior of nucleus density and island size distributions in the initial stage of growth is investigated by using kinetic Monte Carlo simulations. The results show that the temperature dependence of nucleus density and island size distributions governed by the reexchanging-controlled nucleation at high temperatures exhibits similar scaling behavior to that obtained by the standard diffusion-mediated nucleation at low temperatures. However, at intermediate temperatures, the exchanging-controlled nucleation leads to an increase of nucleus density with temperature, while the island size distribution scales to a monotonically decreasing function, showing nonstandard scaling behavior. 相似文献
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二层信用策略下部分延期付款的库存模型 总被引:1,自引:0,他引:1
当前二层信用期相关文献考虑的都是零售商提供给其顾客相同的信用期,但现实中零售商往往会根据物品的种类不同提供给顾客不同的信用期.为研究此问题,建立了优化供货周期使零售商平均相关成本最小的库存模型,证明了最优供货周期的存在性,并给出实例加以说明. 相似文献
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Wang Tingting Yin Rongzhang Ye Mingquan Wan Nan Shi Jiadong 《International Journal of Theoretical Physics》2021,60(4):1507-1515
Based on quantum renormalization group (QRG) method, we investigated quantum coherence and quantum phase transition (QPT) in XXZ chain and XY chain, respectively. The results show that both the geometric quantum coherence and entropic coherecne can accurately indicate the QPT at critical point after enough iteration steps. Moreover, the increasing anisotropy parameter destroys the coherence in the XXZ chain, while enhances it in the XY chain. In addition, focused on the XXZ chain we analyzed the nonanalytic phenomena and scaling behaviors with different theoretical exponents in detail.
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关于自同构作用下的不变元 总被引:1,自引:0,他引:1
文章主要讨论了代数(环)、(双)Hopf代数中自同构作用下不变元素的性质,得到一些新的结果:设A是有限维半单代数,则AutA作用下的不变元属于中心,并且举出反例说明这个性质不能一般化到有限维代数、有限维半单(双)Hopf代数. 相似文献