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121.
本文把稳健统计的影响函数概念引入到了概率约束下的随机规划模型中.在一定条件下,得到了三个模型最优解的影响函数表达式. 相似文献
122.
The problem of solving stochastic differential-algebraic equations (SDAEs) of index 1 with a scalar driving Wiener process is considered. Recently, the authors have proposed a class of stiffly accurate stochastic Runge–Kutta (SRK) methods that do not involve any pseudo-inverses or projectors for the numerical solution of the problem. Based on this class of approximation methods, classifications for the coefficients of stiffly accurate SRK methods attaining strong order 0.5 as well as strong order 1.0 are calculated. Further, the mean-square stability of the considered class of SRK methods is analyzed. As the main result, families of A-stable efficient order 0.5 and 1.0 stiffly accurate SRK methods with a minimal number of stages for SDEs as well as for SDAEs are presented. 相似文献
123.
The impact of stochastic lead time reduction on inventory cost under order crossover 总被引:1,自引:0,他引:1
Jack C. Hayya Terry P. Harrison X. James He 《European Journal of Operational Research》2011,211(2):274-281
We use exponential lead times to demonstrate that reducing mean lead time has a secondary reduction of the variance due to order crossover. The net effect is that of reducing the inventory cost, and if the reduction in inventory cost overrides the investment in lead time reduction, then the lead time reduction strategy would be tenable.We define lead time reduction as the process of decreasing lead time at an increased cost. To date, decreasing lead times has been confined to deterministic instances. We examine the case where lead times are exponential, for when lead times are stochastic, deliveries are subject to order crossover, so that we must consider effective lead times rather than the actual lead times. The result is that the variance of these lead times is less than the variance of the original replenishment lead times.Here we present a two-stage procedure for reducing the mean and variance for exponentially distributed lead times. We assume that the lead time is made of one or several components and is the time between when the need of a replenishment order is determined to the time of receipt. 相似文献
124.
In this paper we introduce a methodology for optimizing the expected cost of routing a single vehicle which has a probability of breaking down or failing to complete some of its tasks. More specifically, a calculus is devised for finding the optimal order in which each site should be visited. 相似文献
125.
In this paper, we use random walk theory to describe the length dynamics of microtubules, one of the principal components of the cytoskeleton. We present a simple two-state model (growing and shrinking) of microtubule length evolution that incorporates a variable rate of switching between the states. Using the generating function technique, we calculate the mean length of microtubule, its variance and diffusion coefficient. We also report analytical and computer simulation results for the mean number of positive monomers in microtubule, and find good qualitative agreement with experimental data. 相似文献
126.
We study the steady state of the Abelian sandpile models with stochastic toppling rules. The particle addition operators commute
with each other, but in general these operators need not be diagonalizable. We use their Abelian algebra to determine their
eigenvalues, and the Jordan block structure. These are then used to determine the probability of different configurations
in the steady state. We illustrate this procedure by explicitly determining the numerically exact steady state for a one dimensional
example, for systems of size ≤12, and also study the density profile in the steady state. 相似文献
127.
Tak Kuen Siu 《Applied mathematics and computation》2010,216(11):3184-3190
In this article, we shall explore the state of art of stochastic flows to derive an exponential affine form of the bond price when the short rate process is governed by a Markovian regime-switching jump-diffusion version of the Vasicek model. We provide the flexibility that the market parameters, including the mean-reversion level, the volatility rate and the intensity of the jump component switch over time according to a continuous-time, finite-state Markov chain. The states of the chain may be interpreted as different states of an economy or different stages of a business cycle. We shall provide a representation for the exponential affine form of the bond price in terms of fundamental matrix solutions of linear matrix differential equations. 相似文献
128.
Mircea Grigoriu 《Journal of computational physics》2010,229(22):8406-8429
Mathematical requirements that the random coefficients of stochastic elliptical partial differential equations must satisfy such that they have unique solutions have been studied extensively. Yet, additional constraints that these coefficients must satisfy to provide realistic representations for physical quantities, referred to as physical requirements, have not been examined systematically. 相似文献
129.
S. E. Mangioni H. S. Wio 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(1):67-73
We analyze the effect of a colored non Gaussian noise on a model of
a random walker moving along a ratchet potential. Such a model was
motivated by the transport properties of motor proteins, like
kinesin and myosin. Previous studies have been realized assuming
white noises. However, for real situations, in general we could
expect that those noises be correlated and non Gaussian. Among other
aspects, in addition to a maximum in the current as the noise
intensity is varied, we have also found another optimal value of the
current when departing from Gaussian behavior. We show the relevant
effects that arise when departing from Gaussian behavior,
particularly related to current's enhancement, and discuss its
relevance for both biological and technological situations. 相似文献
130.
Given a subset E of convex functions from
into
which satisfy growth conditions of order p>1 and an open bounded subset
of
, we establish the continuity of a map μΦμ from the set of all Young measures on
equipped with the narrow topology into a set of suitable functionals defined in
and equipped with the topology of Γ-convergence. Some applications are given in the setting of periodic and stochastic homogenization. 相似文献