气—固两相自由射流的粒子仿真方法

采用粒子仿真方法直接跟踪颗粒相运动轨迹,采用NND格式求解NS方程,数值模拟了气-固两相自由射流流场.计算结果表明,将粒子仿真与CFD方法相结合是研究气-固两相流动问题的有效途径.颗粒相参数变化将对气体流场产生一定影响.     

基于敌后侦察与诱骗博弈的远程火力打击战法*

对敌后侦察反军事诱骗的远程火力打击战法的定量分析是战役研究中尚未解决的关键问题之一,根据信息作战原理,运用仿真和统计学分析的混合方法,建立基于概率的二人非零和(TPNZS)非合作博弈模型,设计基于侦察与诱骗博弈的远程火力打击战法,定量分析我方的敌后侦察和敌方的军事诱骗对远程信息与火力联合打击能力的影响,并对一个典型实例的初步试验及分析结果表明:与敌后侦察和军事诱骗有关的正确识别目标和错误识别目标的概率以及远程火力命中目标的概率是评估远程信息与火力联合打击能力的关键,而对评估结果进行博弈分析则是远程火力打击战法设计的关键,用识别正确目标和错误目标能力以及远程火力命中目标能力描述的基于敌后侦察与诱骗博弈的远程火力最优打击战法为Δ*=(0,Δ2*,1-Δ2*)=(0.0000,0.7727,0.2273),被打击方对远程火力打击的最优战法为π*=(π1*,0,1-π1*)=(0.8511,0.0000,0.1489)。     

舰载武器系统零位检测与规正方法

零位检测与规正是作战系统装舰的基础工作,也是武器系统准确打击目标的前提和基础.鉴于传统瞄星方法和标定物标定方法的局限性,以在工程中遇到的特定环境下的武器系统标定为例,分析了具体环境下武器系统零位检测与规正的创新性运用,提出了"线标定法",以为类似情形下的武器系统或作战系统标定提供借鉴.     

搜索路径给定时的搜索对策问题及其应用

搜索路径给定时的最优搜索方案问题,也可以理解为是关于搜索者和目标的二人对策问题,主要讨论了当搜索路径给定时的单个搜索者和单个目标的搜索对策问题。首先根据问题的特点,利用动态规划和迭代的方法,确定关于目标逃逸路径混合策略的最优分区,证明该分区是多面体凸集;针对目标不同逃逸路径的分区,求出搜索者的最大期望收益,再将问题转化为二人有限零和对策,计算出搜索者的支付矩阵,确定最优搜索策略。最后结合海军护航行动,对我舰载直升机搜索小型海盗船进行分析和计算,说明搜索路径给定时的最优搜索对策对于双方的资源分配和提高搜索效率具有一定的应用价值。     

Single‐commodity stochastic network design under demand and topological uncertainties with insufficient data

Stochastic network design is fundamental to transportation and logistic problems in practice, yet faces new modeling and computational challenges resulted from heterogeneous sources of uncertainties and their unknown distributions given limited data. In this article, we design arcs in a network to optimize the cost of single‐commodity flows under random demand and arc disruptions. We minimize the network design cost plus cost associated with network performance under uncertainty evaluated by two schemes. The first scheme restricts demand and arc capacities in budgeted uncertainty sets and minimizes the worst‐case cost of supply generation and network flows for any possible realizations. The second scheme generates a finite set of samples from statistical information (e.g., moments) of data and minimizes the expected cost of supplies and flows, for which we bound the worst‐case cost using budgeted uncertainty sets. We develop cutting‐plane algorithms for solving the mixed‐integer nonlinear programming reformulations of the problem under the two schemes. We compare the computational efficacy of different approaches and analyze the results by testing diverse instances of random and real‐world networks. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 154–173, 2017     

Many‐server loss models with non‐poisson time‐varying arrivals

This article proposes an approximation for the blocking probability in a many‐server loss model with a non‐Poisson time‐varying arrival process and flexible staffing (number of servers) and shows that it can be used to set staffing levels to stabilize the time‐varying blocking probability at a target level. Because the blocking probabilities necessarily change dramatically after each staffing change, we randomize the time of each staffing change about the planned time. We apply simulation to show that (i) the blocking probabilities cannot be stabilized without some form of randomization, (ii) the new staffing algorithm with randomiation can stabilize blocking probabilities at target levels and (iii) the required staffing can be quite different when the Poisson assumption is dropped. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 177–202, 2017     

Statistical analysis for masked system life data from Marshall‐Olkin Weibull distribution under progressive hybrid censoring

This paper considers the statistical analysis of masked data in a series system, where the components are assumed to have Marshall‐Olkin Weibull distribution. Based on type‐I progressive hybrid censored and masked data, we derive the maximum likelihood estimates, approximate confidence intervals, and bootstrap confidence intervals of unknown parameters. As the maximum likelihood estimate does not exist for small sample size, Gibbs sampling is used to obtain the Bayesian estimates and Monte Carlo method is employed to construct the credible intervals based on Jefferys prior with partial information. Numerical simulations are performed to compare the performances of the proposed methods and one data set is analyzed.     

军民融合产业创新集群的形成

在军民融合发展战略与创新驱动发展战略深入推进进程中,军民融合产业创新集群成为军民融合产业发展的重要创新形式,其形成问题研究更是对其发展与演化具有重要影响。以军民融合产业创新集群的内涵着手,通过刺激—反应模型与演化博弈模型,分析其形成过程与促进措施。研究表明,军民融合产业创新集群作为复杂适应系统,创新主体的适应性能力及其内在关系是集群形成的关键所在;为使合作创新行为成为演化博弈的稳定策略,从合作创新能力系数和合作创新成本、拥有的创新资源以及政府资金支持三个方面剖析集群形成的促进作用,对军民融合产业创新集群的发展与演化研究奠定基础。     

非相参三点源有源诱偏下ARM弹着点研究

非相参多点源诱偏技术是对抗反辐射导弹(ARM)的有效手段。以ARM目标分辨的二分组理论和双点源诱偏的仿真结果为依据,对等功率三点源诱偏的2种经典布局的ARM落点整体分布进行预测。通过对ARM落点和系统被击中概率曲线的分析及拟合处理,验证了预测的正确性及系统被击中概率与占地面积的相关性,为通信辐射源抗ARM的布设提供一定的参考。     

Return policy: Hassle‐free or your money‐back guarantee?

This article compares the profitability of two pervasively adopted return policies—money‐back guarantee and hassle‐free policies. In our model, a seller sells to consumers with heterogeneous valuations and hassle costs. Products are subject to quality risk, and product misfit can only be observed post‐purchase. While the hassle‐free policy is cost advantageous from the seller's viewpoint, a money‐back guarantee allows the seller to fine‐tune the consumer hassle on returning the product. Thus, when the two return policies lead to the same consumer behaviors, the hassle‐free policy dominates. Conversely, a money‐back guarantee can be more profitable even if on average, high‐valuation consumers experience a lower hassle cost than the low‐valuation ones. The optimal hassle cost can be higher when product quality gets improved; thus, it is not necessarily a perfect proxy or signal of the seller's quality. We further allow the seller to adopt a mixture of these policies, and identify the concrete operating regimes within which these return policies are optimal among more flexible policies. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 403–417, 2014