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111.
Gerhard Hiermann Richard F. Hartl Jakob Puchinger Thibaut Vidal 《European Journal of Operational Research》2019,272(1):235-248
We introduce an electric vehicle routing problem combining conventional, plug-in hybrid, and electric vehicles. Electric vehicles are constrained in their service range by their battery capacity, and may require time-consuming recharging operations at some specific locations. Plug-in hybrid vehicles have two engines, an internal combustion engine and an electric engine using a built-in rechargeable battery. These vehicles can avoid visits to recharging stations by switching to fossil fuel. However, this flexibility comes at the price of a generally higher consumption rate and utility cost.To solve this complex problem variant, we design a sophisticated metaheuristic which combines a genetic algorithm with local and large neighborhood search. All route evaluations, within the approach, are based on a layered optimization algorithm which combines labeling techniques and greedy evaluation policies to insert recharging stations visits in a fixed trip and select the fuel types. The metaheuristic is finally hybridized with an integer programming solver, over a set partitioning formulation, so as to recombine high-quality routes from the search history into better solutions. Extensive experimental analyses are conducted, highlighting the good performance of the algorithm and the contribution of each of its main components. Finally, we investigate the impact of fuel and energy cost on fleet composition decisions. Our experiments show that a careful use of a mixed fleet can significantly reduce operational costs in a large variety of price scenarios, in comparison with the use of a fleet composed of a single vehicle class. 相似文献
112.
Harold J. Kushner 《Queueing Systems》2006,54(4):317-329
Consider a communications network consisting of mobiles and random external data processes, each destined to a particular
destination. Each mobile can serve as a node in the multi-hop path from source to destination. At each mobile the data is
queued according to the source destination pair. The quality of the connecting channels are randomly varying. Time is divided
into small scheduling intervals. At the beginning of each interval, the channels are estimated and this information is used
for the decisions concerning allocation of transmission power and/or time, bandwidth, and perhaps antennas, in a queue and
channel-state dependent way. Under a natural (and “almost” necessary) “average flow” condition, stochastic stability methods
are used to develop scheduling policies that assure stability. The policies are readily implementable and allow a range of
tradeoffs between current rates and queue lengths, under very weak conditions. Because of the non-Markovian nature of the
problem, we use the perturbed Stochastic Liapunov function method. The choice of Liapunov function allows a choice of the
effective performance criteria. All essential factors are incorporated into a “mean rate” function, so that the results cover
many different systems. Extensions concerning acknowledgments, multicasting, non-unique routes, and others are given to illustrate
the versatility of the method, and a useful method for getting the a priori routes is discussed. 相似文献
113.
一类三阶拟线性发展方程的整体解 总被引:1,自引:0,他引:1
杨志坚 《高校应用数学学报(A辑)》1998,13(1):31-38
本文研究一类三阶拟线性发展方程utt-Δut+ut=ni=1xiσi(uxi),(x,t)∈Ω×(0,T)的初边值问题,其中ΩRn(n≥1)为一有界域.证明了只要σi(s)∈C1,σ′i(s)(i=1,…,n)有界并且初始函数满足一定的条件,则上述问题存在唯一的整体弱解. 相似文献
114.
一类半线性卷积积分微分方程的初边值问题 总被引:1,自引:0,他引:1
张卫国 《高校应用数学学报(A辑)》1995,(4):403-410
本文考虑具线性粘弹性杆受粘性阻尼的横振动所引出的积分微分方程的初边值问题,在某些条件下,得到了解的存在性、唯一性、稳定性和正则性的结论。 相似文献
115.
本文主要讨论高维空间非线性波动方程的Cauchy问题整体解的非存在性,我们证明对Uu-△u=f(u),f(u)=c|u|p-1u,当1<p≥时,若初始能量非正,则无论初值数据的ck-范数(连续空间范数)多么小,解按Ck-范数或按Hs(Rn)(S≥1)都在有限时间内Blowup,并且有相同的生命跨度. 相似文献
116.
通过对已有补偿问题的模型进行总结,抽象与升华,本文建立了Banach空间中一般形式多阶段有补偿随机规划问题的一个非线性模型,使已有所有的补偿问题均成为其特例;然后利用可测集值映射理论,正规凸的被积函数的性质及文[8」中的结论等,讨论了所给模型的适定性与其基本性质. 相似文献
117.
B. R. Frieden 《Optics Communications》1998,150(1-6):15-21
We show how, in principle, to solve the ‘blind deconvolution' problem. This is in the context of the problem of imaging through atmospheric turbulence. The approach is digital but not iterative, and requires as input data but two short-exposure intensity images, without the need for reference point sources. By taking the Fourier transform of each image and dividing, a set of linear equations is generated whose unknowns are sampled values of the two random point spread functions that degraded the images. An oversampling by 50% in Fourier space equalizes the number of unknowns and independent equations. With some prior knowledge of spread function support, and in the absence of added noise of image detection, the inverted equations give exact solutions. The two observed images are then inverse filtered to reconstruct the object. 相似文献
118.
Designing delivery districts for the vehicle routing problem with stochastic demands 总被引:4,自引:0,他引:4
Dag Haugland Sin C. Ho Gilbert Laporte 《European Journal of Operational Research》2007,180(3):997-1010
This paper considers the problem of designing districts for vehicle routing problems with stochastic demands. In particular, demands are assumed to be uncertain at the time when the districts are made, and these are revealed only after the districting decisions are determined. Tabu search and multistart heuristics for this stochastic districting problem are developed and compared. Computational results show that tabu search is superior over multistart. 相似文献
119.
In this paper we introduce a new class of facet-inducing inequalities for the Windy Rural Postman Problem and the Windy General
Routing Problem. These inequalities are called Zigzag inequalities because they cut off fractional solutions containing a
zigzag associated with variables with 0.5 value. Two different types of inequalities, the Odd Zigzag and the Even Zigzag inequalities,
are presented. Finally, their application to other known Arc Routing Problems is discussed. 相似文献
120.
T.S. Arthanari 《Discrete Mathematics》2006,306(14):1474-1492
In this paper we define a combinatorial object called a pedigree, and study the corresponding polytope, called the pedigree polytope. Pedigrees are in one-to-one correspondence with the Hamiltonian cycles on Kn. Interestingly, the pedigree polytope seems to differ from the standard tour polytope, Qn with respect to the complexity of testing whether two given vertices of the polytope are nonadjacent. A polynomial time algorithm is given for nonadjacency testing in the pedigree polytope, whereas the corresponding problem is known to be NP-complete for Qn. We also discuss some properties of the pedigree polytope and illustrate with examples. 相似文献