共查询到20条相似文献,搜索用时 15 毫秒
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Queueing Systems - Stochastic fluid models have been widely used to model the level of a resource that changes over time, where the rate of variation depends on the state of some continuous-time... 相似文献
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The steady flow of a second-order thermo-viscous fluids over a moving infinite flat plate is examined. It is observed that in the absence of any body force in the flow region, a constant temperature gradient is generated, which depends upon the plate velocity and material constants. The mean velocity, mean bulk temperature and Nusselt number are calculated. 相似文献
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《Journal of Computational and Applied Mathematics》2005,176(1):59-76
We introduce new methods in the class of boundary value methods (BVMs) to solve boundary value problems (BVPs) for a second-order ODE. These formulae correspond to the high-order generalizations of classical finite difference schemes for the first and second derivatives. In this research, we carry out the analysis of the conditioning and of the time-reversal symmetry of the discrete solution for a linear convection–diffusion ODE problem. We present numerical examples emphasizing the good convergence behavior of the new schemes. Finally, we show how these methods can be applied in several space dimensions on a uniform mesh. 相似文献
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Networks of queues with finite and infinite source customers have been used to study the interaction between the batch jobs and interactive jobs in computer systems. Earlier Kaufman ([1], PP-345-348) developed accurate approximations for a simple nonproduct form network of this type. In this paper we offer exact solutions for the same model with one finite source customer. We study both FIFO and LIFO disciplines at the contention node. The results are derived for the case where the finite source think time and service time distributions are generalized hyperexponential. 相似文献
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Fluid flow in naturally fractured porous media can always be regarded as an unbounded domain problem and be better solved by finite/infinite elements. In this paper, a three-dimensional two-direction mapped infinite element is generated and combined with conventional finite elements and one direction infinite element to simulate poroelasticity. Therefore, the entire semi-infinite domain can be included in the numerical analysis. Both single- and dual-porosity porous media are considered. For the purpose of validation, we compare the results of finite/infinite elements with those of finite elements under two extreme boundary conditions. The comparison indicated that mapped infinite element is an appropriate approach to model fluid flow in porous media and provides an intermediate solution. 相似文献
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Carsten Thomassen 《Journal of Combinatorial Theory, Series B》1980,29(2):244-271
We present a short proof of the following theorems simultaneously: Kuratowski's theorem, Fary's theorem, and the theorem of Tutte that every 3-connected planar graph has a convex representation. We stress the importance of Kuratowski's theorem by showing how it implies a result of Tutte on planar representations with prescribed vertices on the same facial cycle as well as the planarity criteria of Whitney, MacLane, Tutte, and Fournier (in the case of Whitney's theorem and MacLane's theorem this has already been done by Tutte). In connection with Tutte's planarity criterion in terms of non-separating cycles we give a short proof of the result of Tutte that the induced non-separating cycles in a 3-connected graph generate the cycle space. We consider each of the above-mentioned planarity criteria for infinite graphs. Specifically, we prove that Tutte's condition in terms of overlap graphs is equivalent to Kuratowski's condition, we characterize completely the infinite graphs satisfying MacLane's condition and we prove that the 3-connected locally finite ones have convex representations. We investigate when an infinite graph has a dual graph and we settle this problem completely in the locally finite case. We show by examples that Tutte's criterion involving non-separating cycles has no immediate extension to infinite graphs, but we present some analogues of that criterion for special classes of infinite graphs. 相似文献
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Results byW. Mader and the authors on the connectivity of finite graphs are generalized to include infinite graphs. In the infinite case a distinction must be made concerning the distribution of finite and infinite components with respect to the separating sets. Results are obtained relating these components to the atoms. 相似文献
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A second-order fluid flow model of a queue with finite capacity buffer and variable net input process is presented, based
on the previous work of Karandikar and Kulkarni (1995). Queue length is modelled as a Brownian motion whose parameters are
controlled by a finite state Markov chain. The process, termed a Markov modulated regulated Brownian motion (MMRBM), provides
analytical solutions for steady state queue length distributions, overflow losses and idleness probabilities using boundary
regulators. Applications of the model include queues with failure-prone servers and ATM statistical multiplexers with variable
traffic loads.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Let G be an infinite locally finite connected graph. We study the reconstructibility of G in relation to the structure of its end set
. We prove that an infinite locally finite connected graph G is reconstructible if there exists a finite family (Ωi)0i (n2) of pairwise finitely separable subsets of
such that, for all x,y,x′,y′V(G) and every isomorphism f of G−{x,y} onto G−{x′,y′} there is a permutation π of {0,…,n−1} such that
for 0i<n. From this theorem we deduce, as particular consequences, that G is reconstructible if it satisfies one of the following properties: (i) G contains no end-respecting subdivision of the dyadic tree and has at least two ends of maximal order; (ii) the set of thick ends or the one of thin ends of G is finite and of cardinality greater than one. We also prove that if almost all vertices of G are cutvertices, then G is reconstructible if it contains a free end or if it has at least a vertex which is not a cutvertex. 相似文献
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ShengJun Fan Long Jiang DeJian Tian 《Stochastic Processes and their Applications》2011,121(3):427-440
This paper is devoted to solving one-dimensional backward stochastic differential equations (BSDEs), where the time horizon may be finite or infinite and the assumptions on the generator g are not necessary to be uniform on t. We first show the existence of the minimal solution for this kind of BSDEs with linear growth generators. Then, we establish a general comparison theorem for solutions of this kind of BSDEs with weakly monotonic and uniformly continuous generators. Finally, we give an existence and uniqueness result for solutions of this kind of BSDEs with uniformly continuous generators. 相似文献
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In this paper, we consider discrete second-order multi-point boundary value problem with a p-Laplacian. By giving condition on f and applying Krasnosel’skii fixed point theorem, we ensure the existence of at least one positive solution and show the existence of eigenvalue intervals. 相似文献
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J. Fritz 《Probability Theory and Related Fields》1982,59(4):479-490
Summary Let G be the formal generator of a d-dimensional stochastic gradient system associated to an interaction potential U. If G d = 0 for such smooth that G IL
1(), then certain moment conditions imply that is a Gibbs random field for U. If U satisfies a stability condition, and d2 or is translation invariant, then these moment conditions can be replaced by a natural support condition. Results of Holley and Stroock [6] are extended to certain unbounded spin systems. 相似文献
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