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     

Determining a threshold control policy for an imperfect production system with rework jobs

Consider a threshold control policy for an imperfect production system with only a work center handling both regular and rework jobs. An imperfect production system studied here, generates defect jobs by factors other than machine failures. A threshold control or (ω, s) policy sets the guideline for a work center to switch between regular and rework jobs. A production cycle begins with loading and processing of several batches of regular jobs with a lot size equal to s. The outcome of each completed regular job is an independent Bernoulli trial with three possibilities: good, rework, or scrap. Once the work center accumulates more than a threshold ω of rework jobs, it finishes the last batch of regular jobs and switches to rework jobs. The objective of this research is to find a threshold ω and a lot size s that maximize the average long‐term profit. The ultimate goal is to construct a simple algorithm to search for ω and s that can be implemented directly in production management systems, as a result of this work. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 273–301, 1999     

空间信息栅格体系与服务聚合技术

空间信息应用中存在的数据海量、分布异构、处理复杂、计算密集等问题制约了空间数据和信息的广泛共享和应用。空间信息栅格(SIG)以Grid和WebServices技术为核心,共享并汇集地理上分布的海量空间信息资源,实现动态整合与集成。在构建开放性SIG七层应用体系的基础上,重点研究SIG服务聚合技术,基于Petri网和图论提出了一种新的服务聚合流程模型(服务/资源网),同时构建了可扩展的服务动态选择模型(SISM),实现服务聚合过程中的动态服务选择。结合国家地质调查业务应用,通过地下水资源评价应用实例对SIG的实用性和有效性进行了验证。     

二值化联合变换相关器识别复杂背景目标时的阈值选取

讨论了利用二值化联合变换相关器对复杂背景目标进行相关识别的阈值选取问题。由于不同阈值对二值化联合变换相关器识别结果有很大的影响,阈值过高,会损失过多的联合变换功率谱中的有效成份,使相关峰减弱;阈值过低,会使联合功率谱中的噪声放大,相关峰可能被淹没在噪声之中。因而存在一个最佳阈值。实验表明,最佳阈值位于联合功率谱最大灰度值的40%～50%之间,在此阈值范围内,相关峰值较高,噪声也得到有效抑制。     

基于变权的军事供应链合作伙伴评价研究

合作伙伴的评价与选择影响着军事供应链的整体效能.为正确选择军事供应链合作伙伴,提升后勤保障效能,从分析构建军事供应链合作伙伴的评价体系入手,基于多因子影响、多条件变化建立了动态变值、变权模糊评价模型,举例说明了这一模型的可行性.这一研究对正确选择军事供应链合作伙伴提供了有力的支撑.     

全地形加油车高机动性底盘选型研究

底盘选型研究是保证新型加油车机动性大幅提升的基础.评析了标志地面车辆通行能力的多种概念,根据车辆机动性评估原理,提出了涵盖车辆快速性、支承通过性和几何通过性的机动性量化评估模型.应用该评估模型评定了备选车辆的机动性,验证了评估模型的有效性,选定了全地形加油车高机动性底盘,为车辆机动性的量化评估提供了研究思路.     

基于ICP的编队预定目标选择方法

如何对编队预定目标进行自动选择,是超视反舰导弹亟待解决的一个问题.反舰末制导雷达对编队预定目标的选择,可通过点集匹配来实现,基于此提出了一种运用ICP (Iterated Closest Point)算法进行编队预定目标选择的方法.首先通过一个粗搜索过程来确保ICP算法的初始值选取性能,然后运用ICP算法精确搜索最佳匹...     

基于小波变换和中值滤波的无人机图像去噪算法

在无人机航拍图像的实时传输过程中,有可能会同时受到脉冲和高斯混合噪声的污染,为后续图像的识别造成很大的困难.针对这种情况,提出了一种基于中值滤波和小波变换相结合的图像去噪方法.仿真结果表明,该方法不仅能有效地滤除脉冲和高斯的混合噪声,而且可以很好地保留图像的细节信息,改善图像的视觉效果.     

Fuzzy recognition of missile borne multi-line array infrared detection based on size calculating

In order to improve the infrared detection and discrimination ability of the smart munition to the dy-namic armor target under the complex background, the multi-line array infrared detection system is established based on the combination of the single unit infrared detector. The surface dimension features of ground armored targets are identified by size calculating solution algorithm. The signal response value and the value of size calculating are identified by the method of fuzzy recognition to make the fuzzy classification judgment for armored target. According to the characteristics of the target signal, a custom threshold de-noising function is proposed to solve the problem of signal preprocessing. The multi-line array infrared detection can complete the scanning detection in a large area in a short time with the characteristics of smart munition in the steady-state scanning stage. The method solves the disadvan-tages of wide scanning interval and low detection probability of single unit infrared detection. By reducing the scanning interval, the number of random rendezvous in the infrared feature area of the upper surface is increased, the accuracy of the size calculating is guaranteed. The experiments results show that in the fuzzy recognition method, the size calculating is introduced as the feature operator, which can improve the recognition ability of the ground armor target with different shape size.     

基于蚂蚁聚类算法的炮兵阵地选取方法

在对炮兵作战地域进行地形分析的基础上,提出运用蚂蚁聚类算法选取炮兵阵地的方法.针对炮兵阵地配置的特殊要求,将模糊数学中的隶属度概念引入到炮兵阵地聚类算法之中.最后通过实验分析了此方法的优缺点,对炮兵指挥决策有一定的参考价值.