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991.
We consider optimal control problems for one-dimensional diffusion processes y x (t) = y v x (t), solutions dy x (t) = g(y x (t) dt + σ(y x (t)(dw) + dv t with y x(0) = x& isinv;[a,b], the control processes v t are increasing, positive, and adapted. Several types of expected cost structures associated with each policy v(.) are adopted, e.g. discounted cost, long term average cost and time average cost. Our work is related to [2,6,12,14,16 and 21], where diffusions are allowed to evolve in the whole space, and to [13] and [20], where diffusions evolve only in bounded regions. We shall present some analytic results about value functions, mainly their characterizations, by simple dynamic programming arguments. Several simple examples are explicitly solved to illustrate the singular behaviour of our problems 相似文献
992.
We consider optimal control problems for one-dimensional diffusion processes [ILM0001] where the control processes υt are increasing, positive, and adapted. Several types of expected cost structures associated with each policy υ(.) are adopted, e.g. discounted cost, long term average cost and time average cost. Our work is related to [2,6,12,14,16 and 21], where diffusions are allowed to evolve in the whole space, and to [13] and [20], where diffusions evolve only in bounded regions. We shall present some analytic results about value functions, mainly their characterizations, by simple dynamic programming arguments. Several simple examples are explicitly solved to illustrate the singular behaviour of our problems. 相似文献
993.
Circle graphs with girth at least five are known to be 2-degenerate [A.A. Ageev, Every circle graph with girth at least 5 is 3-colourable, Discrete Math. 195 (1999) 229-233]. In this paper, we prove that circle graphs with girth at least g≥5 and minimum degree at least two contain a chain of g−4 vertices of degree two, which implies Ageev’s result in the case g=5. We then use this structural property to give an upper bound on the circular chromatic number of circle graphs with girth at least g≥5 as well as a precise estimate of their maximum average degree. 相似文献
994.
Analysis of a predator-prey model with modified Leslie-Gower and Holling-type II schemes with stochastic perturbation 总被引:1,自引:0,他引:1
Chunyan Ji Daqing Jiang Ningzhong Shi 《Journal of Mathematical Analysis and Applications》2009,359(2):482-1233
In this paper, we consider a predator-prey model with modified Leslie-Gower and Holling-type II schemes with stochastic perturbation. We show there is a unique positive solution to the system with positive initial value, and mainly investigate the long time behavior of the system. Condition for the system to be extinct is given and persistent condition is established. At last, numerical simulations are carried out to support our results. 相似文献
995.
B. K. Pagnoncelli S. Ahmed A. Shapiro 《Journal of Optimization Theory and Applications》2009,142(2):399-416
We study sample approximations of chance constrained problems. In particular, we consider the sample average approximation (SAA) approach and discuss the convergence properties of the resulting problem. We discuss how one can use the SAA method
to obtain good candidate solutions for chance constrained problems. Numerical experiments are performed to correctly tune
the parameters involved in the SAA. In addition, we present a method for constructing statistical lower bounds for the optimal
value of the considered problem and discuss how one should tune the underlying parameters. We apply the SAA to two chance
constrained problems. The first is a linear portfolio selection problem with returns following a multivariate lognormal distribution.
The second is a joint chance constrained version of a simple blending problem.
B.K. Pagnoncelli’s research was supported by CAPES and FUNENSEG.
S. Ahmed’s research was partly supported by the NSF Award DMI-0133943.
A. Shapiro’s research was partly supported by the NSF Award DMI-0619977. 相似文献
996.
Joanna Petela 《Applied mathematics and computation》2009,215(2):481-494
In this paper we consider nonautonomous competitive Kolmogorov systems, which is a generalization of classical Lotka–Volterra competition model. Applying Ahmad and Lazer’s definitions of lower and upper averages of a function, we give the average conditions for the persistence, permanence and global attractivity of the system. 相似文献
997.
Let {εt;t ∈ Z} be a sequence of m-dependent B-valued random elements with mean zeros and finite second moment. {a3;j ∈ Z} is a sequence of real numbers satisfying ∑j=-∞^∞|aj| 〈 ∞. Define a moving average process Xt = ∑j=-∞^∞aj+tEj,t ≥ 1, and Sn = ∑t=1^n Xt,n ≥ 1. In this article, by using the weak convergence theorem of { Sn/√ n _〉 1}, we study the precise asymptotics of the complete convergence for the sequence {Xt; t ∈ N}. 相似文献
998.
In this paper we study zero-sum stochastic games. The optimality criterion is the long-run expected average criterion, and the payoff function may have neither upper nor lower bounds. We give a new set of conditions for the existence of a value and a pair of optimal stationary strategies. Our conditions are slightly weaker than those in the previous literature, and some new sufficient conditions for the existence of a pair of optimal stationary strategies are imposed on the primitive data of the model. Our results are illustrated with a queueing system, for which our conditions are satisfied but some of the conditions in some previous literatures fail to hold. 相似文献
999.
For Vilenkin-like system, the authors define a new operator H*f := supn |Hnf|, where Hnf is the weighted average for partial sums, and prove that H* is of type (Hp* (Gm), Lp(Gm)) for all 1/2 < p ≤∞. As a consequence, the authors prove the operator S*f := supn |Snf| is of type (p, p) for 1 < p < ∞, where Snf is the n-partial sum. 相似文献
1000.
Yves Lucet Heinz H. Bauschke Mike Trienis 《Computational Optimization and Applications》2009,43(1):95-118
A new computational framework for computer-aided convex analysis is proposed and investigated. Existing computational frameworks
are reviewed and their limitations pointed out. The class of piecewise linear-quadratic functions is introduced to improve
convergence and stability. A stable convex calculus is achieved using symbolic-numeric algorithms to compute all fundamental
transforms of convex analysis. Our main result states the existence of efficient (linear time) algorithms for the class of
piecewise linear-quadratic functions. We also recall that such class is closed under convex transforms. We illustrate the
results with numerical examples, and validate numerically the resulting computational framework. 相似文献