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931.
本文研究了一类不相关平行机的排序问题,在该问题中工件的加工时间既具有学习效应,又资源可控,也就是说在该问题模型中,工件的实际加工时间为其正常的加工时间、加工过程中工件所处位置以及加工时间可控这些变量的函数。该研究的目的是为使得总机器负载和总的控制费用的加权和最小以及总的完工时间和总的控制费用的加权和最小。文章通过对问题的相关性质的分析和证明找到了一个解决问题的最优化算法,并且也证明了在处理机的数量给定的条件下,该问题的时间复杂性为O(nm+2),最后也给出了相应的数值例子来阐述该问题。 相似文献
932.
We propose a new globalization strategy that can be used in unconstrained optimization algorithms to support rapid convergence from remote starting points. Our approach is based on using multiple points at each iteration to build a sequence of representative models of the objective function. Using the new information gathered from those multiple points, a local step is gradually improved by updating its direction as well as its length. We give a global convergence result and also provide the parallel implementation details accompanied with a numerical study. Our numerical study shows that the proposed algorithm is a promising alternative as a globalization strategy. 相似文献
933.
Quan Xu Ning Wang Bocheng Bao Mo Chen Changdi Li 《Journal of Applied Analysis & Computation》2016,6(4):1152-1163
By bridging a generalized memristor between a passive $LC$ oscillator and an active $RC$ filter, a simple and feasible memristive Chua''s circuit is presented. The generalized memristor without grounded limitation is equivalently achieved by a full-wave rectifier cascaded with a first-order parallel $RC$ filter. The dynamical characteristics of the proposed circuit are investigated both theoretically and numerically, from which it can be found that the circuit has three unstable equilibrium points and demonstrates complex nonlinear phenomena. The experimental circuit is easy to implement and the measurement results validate the results of theoretical analyses. 相似文献
934.
Prosenjit Bose Vida Dujmović Danny Krizanc Stefan Langerman Pat Morin David R. Wood Stefanie Wuhrer 《Journal of Graph Theory》2008,58(3):191-209
A graph G is a 2‐tree if G = K3, or G has a vertex v of degree 2, whose neighbors are adjacent, and G/ v is a 2‐ tree. A characterization of the degree sequences of 2‐trees is given. This characterization yields a linear‐time algorithm for recognizing and realizing degree sequences of 2‐trees. © 2008 Wiley Periodicals, Inc. J Graph Theory 58:191‐209, 2008 相似文献
935.
介绍了采用新型传感元件GP-16火焰检测电子管实现非接触式火焰检测的方法。并给出了完成其功能的电路图. 相似文献
936.
We describe the possible holonomy groups of simply connected irreducible non-locally symmetric pseudo-Riemannian spin manifolds which admit parallel spinors. 相似文献
937.
Stephen Fletcher 《Journal of Solid State Electrochemistry》2007,11(7):965-969
We propose a new model for the elementary act of electron transfer between two species in solution. The central idea is that
the solution in the immediate vicinity of each species may be represented by an equivalent circuit consisting of a Debye circuit
shunted by a resistor. Based on this insight, we derive a new formula for the one-dimensional potential energy profile of
a coupled donor–acceptor pair at finite (but large) separation d, along a charge-fluctuation reaction co-ordinate, at fixed radii of the transition states. The corresponding reorganisation
energy of the reaction is also derived, and it is found to differ from that in the Marcus theory. In particular, the new model
predicts that the reorganisation energy is independent of the static dielectric constant of the solution, whereas the old model predicts a strong dependence. The difference is
traced to the fact that the Marcus theory omits consideration of the work required to form the charge fluctuations and focuses
instead on the work required to localise the charge fluctuations. In general, the equivalent circuit approach permits many
of the difficult-to-derive equations of non-equilibrium polarisation theory to be written down by inspection. 相似文献
938.
Arnal Josep; Migallon Violeta; Penades Jose; Szyld Daniel B. 《IMA Journal of Numerical Analysis》2008,28(1):143-161
939.
Towards a scalable fully-implicit fully-coupled resistive MHD formulation with stabilized FE methods
J.N. Shadid R.P. Pawlowski J.W. Banks L. Chacón P.T. Lin R.S. Tuminaro 《Journal of computational physics》2010,229(20):7649-7671
This paper explores the development of a scalable, nonlinear, fully-implicit stabilized unstructured finite element (FE) capability for 2D incompressible (reduced) resistive MHD. The discussion considers the implementation of a stabilized FE formulation in context of a fully-implicit time integration and direct-to-steady-state solution capability. The nonlinear solver strategy employs Newton–Krylov methods, which are preconditioned using fully-coupled algebraic multilevel preconditioners. These preconditioners are shown to enable a robust, scalable and efficient solution approach for the large-scale sparse linear systems generated by the Newton linearization. Verification results demonstrate the expected order-of-accuracy for the stabilized FE discretization. The approach is tested on a variety of prototype problems, including both low-Lundquist number (e.g., an MHD Faraday conduction pump and a hydromagnetic Rayleigh–Bernard linear stability calculation) and moderately-high Lundquist number (magnetic island coalescence problem) examples. Initial results that explore the scaling of the solution methods are presented on up to 4096 processors for problems with up to 64M unknowns on a CrayXT3/4. Additionally, a large-scale proof-of-capability calculation for 1 billion unknowns for the MHD Faraday pump problem on 24,000 cores is presented. 相似文献
940.
Leila Ribeiro 《Applied Categorical Structures》1999,7(4):405-430
The specification of complex systems is usually done by the divide and conquer idea: the system is divided into smaller, less complex components that are developed separately and then merged in some way to form the specification of the whole system. The main aim of this paper is to provide an approach to the parallel composition of graph grammars, formalizing the intuitive idea of divide and conquer described above. This parallel composition of graph grammars provides a suitable formalism for the specification of concurrent systems based on the specifications of their components. Dividing is formalized by special graph grammar morphisms, called specialization morphisms. These morphisms also describe structural and behavioural compatibilities between graph grammars. As a main result, we characterize the parallel composition as the pullback in the category of graph grammars. 相似文献