航空装备抢修时间估算方法

装备战场抢修是保持和恢复战斗力的重要方法,而抢修时间对战场抢修的效果有着重要影响,甚至直接影响着战争的进程。准确预测并确定装备的抢修时间有利于战场指挥员合理分配抢修力量,有针对性地开展抢修工作,以最大程度地保持和恢复装备战斗力,使战伤装备尽快重新投入战斗。以航空装备某电子系统为例,建立了战场抢修时间的计算模型,并对模型进行求解,实例证明,该方法对于预测并确定战场抢修时间提供了一种有效的途径。     

q∝△(T~(-1))传热时三热源热泵的最优性能普遍关系

本文导出工质与三个热源间的传热系数分别为。α、β和γ,传热规律为q~∝△(T~(-1))时,内可逆三热源热泵的最佳供热系数ψ与供热率Π间的关系:ψ<1时,Π=K_1ψ[T_p(T_H-T_ο)-T_H(T_p-Tο)ψ]/[T_HT_pT_ο(1-△_1ψ)~2];ψ>1时,Π=K_2ψ[T_p(T_H-T_ο)-T_H(T_P-T_ο)ψ]/[T_HT_pT_ο(△_2-ψ)~2];式中,K_1=αγ/(α~(1/2)+γ~(1/2))~2,K_2=βγ/(β~(1/2)+γ~(1/2))~2,△_1=(α/β)~(1/2)(β~(1/2)-r~(1/2)/(α~(1/2)+γ~(1/2)),△_2=(β/α)~(1/2)(α~(1/2)-γ~(1/2))/(β~(1/2)+γ~(1/2))。由此可得许多有用的关系。     

Production‐inventory systems with imperfect advance demand information and updating

We consider a supplier with finite production capacity and stochastic production times. Customers provide advance demand information (ADI) to the supplier by announcing orders ahead of their due dates. However, this information is not perfect, and customers may request an order be fulfilled prior to or later than the expected due date. Customers update the status of their orders, but the time between consecutive updates is random. We formulate the production‐control problem as a continuous‐time Markov decision process and prove there is an optimal state‐dependent base‐stock policy, where the base‐stock levels depend upon the numbers of orders at various stages of update. In addition, we derive results on the sensitivity of the state‐dependent base‐stock levels to the number of orders in each stage of update. In a numerical study, we examine the benefit of ADI, and find that it is most valuable to the supplier when the time between updates is moderate. We also consider the impact of holding and backorder costs, numbers of updates, and the fraction of customers that provide ADI. In addition, we find that while ADI is always beneficial to the supplier, this may not be the case for the customers who provide the ADI. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

Multiple subset sum with inclusive assignment set restrictions

In a traditional multiple subset sum problem (MSSP), there is a given set of items and a given set of bins (or knapsacks) with identical capacities. The objective is to select a subset of the items and pack them into the bins such that the total weight of the selected items is maximized. However, in many applications of the MSSP, the bins have assignment restrictions. In this article, we study the subset sum problem with inclusive assignment set restrictions, in which the assignment set of one item (i.e., the set of bins that the item may be assigned to) must be either a subset or a superset of the assignment set of another item. We develop an efficient 0.6492‐approximation algorithm and test its effectiveness via computational experiments. We also develop a polynomial time approximation scheme for this problem. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

Designing acceptance sampling schemes for life testing with mixed censoring

Mixed censoring is useful extension of Type I and Type II censoring and combines some advantages of both types of censoring. This paper proposes a general Bayesian framework for designing a variable acceptance sampling scheme with mixed censoring. A general loss function which includes the sampling cost, the time‐consuming cost, the salvage value, and the decision loss is employed to determine the Bayes risk and the corresponding optimal sampling plan. An explicit expression of the Bayes risk is derived. The new model can easily be adapted to create life testing models for different distributions. Specifically, two commonly used distributions including the exponential distribution and the Weibull distribution are considered with a special decision loss function. We demonstrate that the proposed model is superior to models with Type I or Type II censoring. Numerical examples are reported to illustrate the effectiveness of the method proposed. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

战车火控系统射击命中三要素函数误差分析

火控系统射击(函数)误差可分解为射弹散布函数误差和火控射击准备函数误差。而射击准备函数则是命中三要素函数即瞄准函数、解算函数和控制函数的合成函数。命中三要素的提出,为火控系统射击误差(精度)的分析提供了新的途径。它们均是命中目标的关键要素,又各具特色,为火控系统射击精度乃至系统反应速度的提高,指出了应该努力的方向。针对此进行了具体的分析。     

鱼雷寿命周期费用研究技术

随着技术的发展,寿命周期费用的研究正日益受到关注。评述了国内外寿命周期费用方面的研究现状,介绍了鱼雷寿命周期费用研究方法的内容及用途,探讨了费用估算的一般方法,在鱼雷寿命周期费用分解原则的基础上给出了鱼雷寿命周期费用分解结构,讨论了寿命周期费用研究方法急需解决的主要问题,并对其今后的发展方向做了展望。     

基于支持向量机的飞机备件需求预测

支持向量机是一种机器学习算法,在国外已广泛应用于工程实践领域。首先探讨了支持向量机回归预测模型的学习和预测机制,分析其中三个重要参数对算法的影响规律,得出一套定性的参数选择方法,然后将支持向量机引入到装备综合保障分析之中,构建了飞机备件智能预测模型,并对某型军用飞机备件需求进行了预测和分析,结果表明:基于支持向量机的备件需求预测是有效的、可行的。     

某型制导炸弹实时仿真系统设计

采用训练仿真系统进行武器装备的维修和操作训练是当今装备的发展趋势。某型制导炸弹是我军即将装备部队的精确制导武器,为了提高训练质量、节约训练经费和延长装备寿命,迫切需要研制该型弹训练仿真系统。介绍了基于PC/104总线的该型制导炸弹实时仿真系统的软硬件设计与实现。该系统具有操作简单,模拟控制信号精确,检测迅速准确,可扩展性强等特点,满足了部队训练和院校实验室教学的要求。     

时域分析在雷达动目标识别中的应用

本文通过对地面几类目标运动特性的统计研究,利用线性预测的方法进行目标特征的提取,进而用模式识别的理论对地面目标进行自动识别,取得了良好的识别效果。