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51.
研究一类具有两种随机扰动的SISV传染病模型.对于第一种随机SISV模型,证明对任给的非负初值,该随机模型一定存在唯一的全局正解,并讨论该随机模型的解围绕确定性模型的无病平衡点的渐近行为;对于第二种随机SISV模型,通过构造适当的Lyapunov泛函证明该随机模型的解是随机渐近稳定的. 相似文献
52.
抢险救灾非战争军事行动包括道路抢修和物资运输等任务,而这两类任务在灾后应急资源调度中存在关联性的影响,且面临路网结构可变及需求随机模糊等挑战,对此,提出了一种非确定性应急资源调度网络双层规划模型,设计了基于蒙特卡洛方法与遗传算法耦合的智能启发式求解策略.通过对典型情境下应急资源调度案例进行分析建模和数值求解,说明了该模型和算法的合理性和有效性. 相似文献
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针对水面舰艇对海作战网络的特点,基于复杂网络"反社区"性质,将对海作战网络描述成"反社区"有向赋权图。结合传统可靠性分析方法,提出了一种新的可靠性评价指标,进一步扩展了传统可靠性指标的4个特性,并通过实例仿真,证明了该指标的有效性。该方法将传统可靠性理论与复杂网络理论有效地结合起来,将进一步扩大复杂网络的适用范围。 相似文献
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We consider a finite horizon periodic review, single product inventory system with a fixed setup cost and two stochastic demand classes that differ in their backordering costs. In each period, one must decide whether and how much to order, and how much demand of the lower class should be satisfied. We show that the optimal ordering policy can be characterized as a state dependent (s,S) policy, and the rationing structure is partially obtained based on the subconvexity of the cost function. We then propose a simple heuristic rationing policy, which is easy to implement and close to optimal for intensive numerical examples. We further study the case when the first demand class is deterministic and must be satisfied immediately. We show the optimality of the state dependent (s,S) ordering policy, and obtain additional rationing structural properties. Based on these properties, the optimal ordering and rationing policy for any state can be generated by finding the optimal policy of only a finite set of states, and for each state in this set, the optimal policy is obtained simply by choosing a policy from at most two alternatives. An efficient algorithm is then proposed. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010 相似文献
57.
We study a stochastic scenario‐based facility location problem arising in situations when facilities must first be located, then activated in a particular scenario before they can be used to satisfy scenario demands. Unlike typical facility location problems, fixed charges arise in the initial location of the facilities, and then in the activation of located facilities. The first‐stage variables in our problem are the traditional binary facility‐location variables, whereas the second‐stage variables involve a mix of binary facility‐activation variables and continuous flow variables. Benders decomposition is not applicable for these problems due to the presence of the second‐stage integer activation variables. Instead, we derive cutting planes tailored to the problem under investigation from recourse solution data. These cutting planes are derived by solving a series of specialized shortest path problems based on a modified residual graph from the recourse solution, and are tighter than the general cuts established by Laporte and Louveaux for two‐stage binary programming problems. We demonstrate the computational efficacy of our approach on a variety of randomly generated test problems. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010 相似文献
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雷达侦察主要通过无源侦察接收设备对空域中敌方雷达辐射源信号进行检测,若要实现对敌辐射源信号的截获,基本条件就是敌雷达信号能量能够达到雷达信号侦收设备的截获灵敏度。然而现代战场中,电磁环境复杂多变,敌雷达信号往往被干扰信号、噪声等掩盖,导致侦收设备漏警概率提高。针对以上问题,提出基于随机共振原理的雷达信号截获判断的方法,增大了截获信号的输出信噪比,解决了由于噪声过大掩盖的雷达信号的侦收问题。将该方法应用于雷达告警接收机的前端截获部分,大大降低了截获系统的漏警概率,保证了整个截获系统的稳定性。仿真实验验证了该方法的有效性。 相似文献
59.
Considering a supply chain with a supplier subject to yield uncertainty selling to a retailer facing stochastic demand, we find that commonly studied classical coordination contracts fail to coordinate both the supplier's production and the retailer's procurement decisions and achieve efficient performance. First, we study the vendor managed inventory (VMI) partnership. We find that a consignment VMI partnership coupled with a production cost subsidy achieves perfect coordination and a win‐win outcome; it is simple to implement and arbitrarily allocates total channel profit. The production cost subsidy optimally chosen through Nash bargaining analysis depends on the bargaining power of the supplier and the retailer. Further, motivated by the practice that sometimes the retailer and the supplier can arrange a “late order,” we also analyze the behavior of an advance‐purchase discount (APD) contract. We find that an APD with a revenue sharing contract can efficiently coordinate the supply chain as well as achieve flexible profit allocation. Finally, we explore which coordination contract works better for the supplier vs. the retailer. It is interesting to observe that Nash bargaining solutions for the two coordination contracts are equivalent. We further provide recommendations on the applications of these contracts. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 305–319, 2016 相似文献
60.
We consider the problem of nonparametric multi-product dynamic pricing with unknown demand and show that the problem may be formulated as an online model-free stochastic program, which can be solved by the classical Kiefer-Wolfowitz stochastic approximation (KWSA) algorithm. We prove that the expected cumulative regret of the KWSA algorithm is bounded above by where κ1, κ2 are positive constants and T is the number of periods for any T = 1, 2, … . Therefore, the regret of the KWSA algorithm grows in the order of , which achieves the lower bounds known for parametric dynamic pricing problems and shows that the nonparametric problems are not necessarily more difficult to solve than the parametric ones. Numerical experiments further demonstrate the effectiveness and efficiency of our proposed KW pricing policy by comparing with some pricing policies in the literature. 相似文献