Optimal control of an M/G/1 queue with impatient priority customers

An optimal operating policy is characterized for the infinite‐horizon average‐cost case of a single server queueing control problem. The server may be turned on at arrival epochs or off at departure epochs. Two classes of customers, each of them arriving according to an independent Poisson processes, are considered. An arriving 1‐customer enters the system if the server is turned on upon his arrival, or if the server is on and idle. In the former case, the 1‐customer is selected for service ahead of those customers waiting in the system; otherwise he leaves the system immediately. 2‐Customers remain in the system until they complete their service requirements. Under a linear cost structure, this paper shows that a stationary optimal policy exists such that either (1) leaves the server on at all times, or (2) turns the server off when the system is empty. In the latter case, we show that the stationary optimal policy is a threshold strategy, this feature being commonplace in most of priority queueing systems and inventory models. However, the optimal policy in our model is determined by two thresholds instead of one. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 201–209, 2001     

两点源干扰情况下数据积累点数对雷达测角精度的影响

两点源干扰是干扰被动雷达导引头 (PRS)的有效手段。但在实际应用中 ,两点源的功率不可能完全相等 ,这就为PRS对抗两点源的干扰提供了契机。通过理论分析和仿真实验证明 ,当两点源偏离导引头的电轴方向不大的情况下 ,只要保证足够的积累点数 ,导引头进行数据积累取均值 ,其结果并不指向两源的“重心”或“质心”而是指向两源中功率较大者 ,并给出了确定积累点数的解析表达式     

The NBUL class of life distribution and replacement policy comparisons

Let X and X_τ denote the lifetime and the residual life at age τ of a system, respectively. X is said to be a NBUL random variable if X_τ is smaller than X in Laplace order, i.e., X_τ ≤_L X. We obtain some characterizations for this class of life distribution by means of the lifetime of a series system and the residual life at random time. We also discuss preservation properties for this class of life distribution under shock models. Finally, under the assumption that the lifetimes have the NBUL property, we make stochastic comparisons between some basic replacement policies. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 578–591, 2001.     

加强成人《高等数学》的习作解题指导

教学中指导学生正确使用数学符号、正确运用基本概念、正确运用函数图象以及探索解题思路等 ,可以提高成人《高等数学》的教学质量 ,也可以提高统考的及格率     

计算机人机交互界面的变化与计算机的发展

讨论人机交互界面性质设定变化对计算机发展的影响问题.认为人与计算机是通过一定界面进行信息交流的,而界面是否友好直接关系到计算机的应用及发展.及时改变人机交互界面的性质是计算机发展的关键.     

反舰导弹仿真中的目标命中判断问题

阐述了模型校核的意义和作用。对属于模型校核范畴的仿真中的系统状态不连贯问题的基本概念通过乒乓球的下落和反舰导弹攻击目标舰艇的例子进行了说明。介绍了已有的解决系统状态不连贯问题的三种方法,并进行了优、缺点分析。给出了反舰导弹仿真中的目标命中判断模型。指出,反舰导弹仿真中的目标命中判断问题是一个系统状态不连贯问题。为解决该问题,提出并应用了一种新方法预测法。利用预测法,最多进行两步最小步长仿真,就能够以要求的精确度检测到任何一个系统状态不连贯。相对于以前的三种方法,在提高仿真效率的同时,预测法还能够避免对系统状态不连贯问题的漏检。     

火力运用对策空间模型

根据空 -地作战的特点 ,提出了软、硬火力单位的概念 ,根据模型提出了作战指数、生存指数 ,为双方的实力与“保卫目标”的安全度分析提供了数量依据 ;根据微分对策和战术原则提出了规范作战模式等概念 ,为构造火力运用、兵力数量需求等算法搭起一个框架。     

Optimal (τ, T) opportunistic maintenance of a k‐out‐of‐n:G system with imperfect PM and partial failure

The opportunistic maintenance of a k‐out‐of‐n:G system with imperfect preventive maintenance (PM) is studied in this paper, where partial failure is allowed. In many applications, the optimal maintenance actions for one component often depend on the states of the other components and system reliability requirements. Two new (τ, T) opportunistic maintenance models with the consideration of reliability requirements are proposed. In these two models, only minimal repairs are performed on failed components before time τ and the corrective maintenance (CM) of all failed components are combined with PM of all functioning but deteriorated components after τ; if the system survives to time T without perfect maintenance, it will be subject to PM at time T. Considering maintenance time, asymptotic system cost rate and availability are derived. The results obtained generalize and unify some previous research in this area. Application to aircraft engine maintenance is presented. © 2000 John Wiley & Sons;, Inc. Naval Research Logistics 47: 223–239, 2000     

KKV质量、质心、转动惯量一体化测量方法研究

从提高动能拦截器质量、质心、转动惯量测量设备在动能拦截器轻小型化发展趋势下的通用程度和性能鲁棒性角度 ,提出一种无称重传感器条件下的质量、质心、转动惯量一体化测量方法。该方法将对动能拦截器质量、质心和转动惯量的测量转化为对不同加载状态下转台摆动周期的测量 ,数学仿真结果表明了该方法在原理上的可行性和有效性     

中锰铸钢坦克履带板连接筋的喷丸强化处理

针对新研制的中锰铸钢坦克履带板装车考核中的特点,提出了对连接筋实施喷丸强化处理的预强化方案.分析了喷丸强化层的组织和硬化特性;还通过连接筋的3点弯曲疲劳试验,探讨了喷丸强化对连接筋疲劳裂纹形成的影响.研究认为,对中锰铸钢坦克履带板连接筋进行喷丸强化预处理,是提高其整体使用寿命的重要途径.