基于多测量融合的粒子滤波跟踪算法

复杂背景下运动目标的可靠跟踪,是计算机视觉领域中一个极具挑战性的问题。提出了一种融合颜色和纹理信息的粒子滤波跟踪算法,在粒子滤波的测量阶段,使用颜色直方图对目标进行颜色描述,用梯度方向向量对目标进行纹理描述。对这两种信息,分别用Bhattacharyya系数和欧几里德距离比较粒子与参考模板的相似性。为解决目标变化和遮挡问题,采用了模板更新策略。实验结果表明该方法是稳健的,能够在复杂的背景下对运动目标进行有效、可靠的跟踪。     

Optimal empty vehicle redistribution for hub‐and‐spoke transportation systems

This article considers the empty vehicle redistribution problem in a hub‐and‐spoke transportation system, with random demands and stochastic transportation times. An event‐driven model is formulated, which yields the implicit optimal control policy. Based on the analytical results for two‐depot systems, a dynamic decomposition procedure is presented which produces a near‐optimal policy with linear computational complexity in terms of the number of spokes. The resulting policy has the same asymptotic behavior as that of the optimal policy. It is found that the threshold‐type control policy is not usually optimal in such systems. The results are illustrated through small‐scale numerical examples. Through simulation the robustness of the dynamic decomposition policy is tested using a variety of scenarios: more spokes, more vehicles, different combinations of distribution types for the empty vehicle travel times and loaded vehicle arrivals. This shows that the dynamic decomposition policy is significantly better than a heuristics policy in all scenarios and appears to be robust to the assumptions of the distribution types. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

杂波环境下红外传感器滤波算法

基于定向概率数据关联滤波(DPDAF)算法,根据红外传感器对目标方位角与俯仰角分辨率不同的特性修正了似然函数,并利用等效观测噪声协方差阵修正滤波增益的思想,构造了一种旨在提高红外传感器跟踪性能的修正定向概率数据关联滤波算法.蒙特卡洛仿真结果表明,新算法对红外目标的跟踪具有比DPDAF更好的跟踪性能.     

运用ECO开发基于UML的工作流系统

运用UML进行建模并运用MDA方法生成系统代码已成为当前工作流系统设计开发的一大发展趋势。经过多年发展的ECO技术为.Net环境下运用MDA方法开发基于UML的稳定高效的软件系统提供了很好支持,而ECOⅢ则通过支持UML动态建模,使得ECO具备了开发基于UML工作流系统的能力。通过示例介绍了运用ECO进行工作流开发的一般流程,着重展现运用ECO开发工作流系统的可行性和高效性。     

一种防空自动化系统效能的模糊综合评估方法

针对防空自动化系统的组成,给出了防空自动化系统效能的指标体系,并通过分析防空自动化系统静态效能和动态效能的关系,运用模糊综合评估和系统性能评价等级划分的方法,在防空自动化系统静态效能评估的基础上,研究了防空自动化系统的动态效能,提出了一种静态效能与动态效能相结合的防空自动化系统模糊综合评估方法。     

高阶BOC信号多区域鉴别器的无模糊多径抑制算法

传统的高阶BOC信号多径抑制算法的有效收敛区间较小,不利于信号的稳定跟踪,因此提出一种多区域鉴别器的高阶BOC多径抑制算法。在伪码误差为零的附近区域,采用优化的QStrobe多径抑制鉴别器,而在其他区域采用收敛区间较大的正交BOC鉴别器。利用卡尔曼滤波器对跟踪误差进行开环估计,判断误差所处区域并进行鉴别器的实时切换。对BOC(15,2.5)和BOC(14,2)信号的仿真结果表明,该算法能够实现无模糊跟踪,且6 d B衰减多径误差包络面积比传统QStrobe算法分别改善了57%和51%。     

高动态GNSS信号多普勒模拟任意阶DDS合成器设计*

为高精度模拟高动态条件下GNSS信号的多普勒特性,本文提出一种任意阶DDS信号合成器的设计方法。设计了任意阶DDS信号合成器的结构;通过理论分析,推导了各级累加器相位初值的计算公式;给出了字长选择方法;经仿真与验证,该方法能精确模拟GNSS信号的多普勒特性。此外,本文提出的DDS设计方法不受阶数的限制,可普遍应用于各类信号模拟器的设计。     

变速跳频通信抗跟踪干扰性能的研究

针对常规跳频通信抗跟踪干扰能力差的问题,分析跟踪干扰原理,提出变速跳频通信。建立数学模型,在干扰容限、压制比和追踪概率方面进行理论分析,分析变速跳频通信抗跟踪干扰对误码率的性能,并用MATLAB进行仿真验证。     

Optimal staffing in nonstationary service centers with constraints

This paper considers optimal staffing in service centers. We construct models for profit and cost centers using dynamic rate queues. To allow for practical optimal controls, we approximate the queueing process using a Gaussian random variable with equal mean and variance. We then appeal to the Pontryagin's maximum principle to derive a closed form square root staffing (SRS) rule for optimal staffing. Unlike most traditional SRS formulas, the main parameter in our formula is not the probability of delay but rather a cost‐to‐benefit ratio that depends on the shadow price. We show that the delay experienced by customers can be interpreted in terms of this ratio. Throughout the article, we provide theoretical support of our analysis and conduct extensive numerical experiments to reinforce our findings. To this end, various scenarios are considered to evaluate the change in the staffing levels as the cost‐to‐benefit ratio changes. We also assess the change in the service grade and the effects of a service‐level agreement constraint. Our analysis indicates that the variation in the ratio of customer abandonment over service rate particularly influences staffing levels and can lead to drastically different policies between profit and cost service centers. Our main contribution is the introduction of new analysis and managerial insights into the nonstationary optimal staffing of service centers, especially when the objective is to maximize profitability. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 615–630, 2017     

某型制导炮弹跟踪模拟训练系统设计

针对某新型制导炮弹系统缺乏模拟仿真训练问题,创新性地设计了一种由旋转编码器、虚拟瞄准镜、FPGA等技术组成的射手跟踪瞄准机械系统,采用Qt、ORGE等软件技术开发了训练和模拟导弹运动的三维场景,达到跟踪目标的效果。分析了系统组成和设计的原理。该模拟训练系统具有结构简单、成本低、操作方便等特点,对提高射手操作能力具有重要意义。