基于加权双曲线定位的DV-Hop改进算法

针对基于双曲线定位的DV-Hop算法中误差项的异方差性引起的定位误差大的问题,提出了一种基于加权双曲线定位的DV-Hop改进算法。算法分析了基于双曲线定位的DV-Hop算法模型中误差项的异方差性,用加权最小二乘法对异方差性进行纠正,对加权最小二乘法中的权值矩阵进行了理论推导并得到与跳数相关的最佳权值矩阵,使得误差项满足同方差性,所得估计值接近最佳线性无偏估计。仿真结果表明,所提算法在定位精度上较目前常见的基于双曲线定位的DV-Hop算法都有一定提高。     

舰艇对空自防御系统集成优化方法

舰艇对空自防御系统的集成优化设计是提高系统使用性能的重要途径，系统地分析了舰艇对空自防御系统集成优化的总体思路和主要工作内容，提出了采用开放式体系架构和基于公共计算服务环境技术的舰艇对空自防御系统集成优化方案。     

应用加权紧致非线性格式的VFE-2钝前缘三角翼转捩模拟

为研究前缘转捩对钝前缘三角翼涡结构的影响,采用高阶精度加权紧致非线性格式和γ-Reθ转捩模型对VFE-2中等半径钝前缘三角翼进行数值模拟。将计算结果与试验结果进行详细对比,结果表明:钝前缘三角翼的前缘分离涡发生在翼尖下游,在特定雷诺数下其具体发生位置受转捩因素影响,采用全湍流模型计算会推迟分离,而耦合转捩模型后的计算结果和试验结果吻合良好。运用耦合转捩模型方法,对钝前缘三角翼涡结构随迎角变化进行模拟。计算结果与试验结果吻合,表明在较小的迎角下,前缘不会产生分离诱导涡;随迎角不断增大,分离诱导涡在三角翼后缘附近产生并向上游移动。     

基于全站仪最佳布站的调炮精度检测方法

针对目前缺少火炮调炮精度检测方法的现状,提出了一种基于全站仪最佳布站的调炮精度检测方法,建立了全站仪测量系统的数学模型,推导了调炮精度检测方法的解算公式,根据火炮调炮范围确定了调炮精度检测中的测量区域,得出全站仪测量系统对于整个测量区域的测量不确定度,结合某型火炮设计了画图法优化过程,得到全站仪测量系统的最佳测量布站位置。精度仿真试验表明,该方法可对调炮精度进行检测,使最佳布站测量系统的精度高于随机布站的精度。     

On scheduling a single machine to minimize a piecewise linear objective function: A compact MIP formulation

We study the scheduling situation in which a set of jobs subjected to release dates and deadlines are to be performed on a single machine. The objective is to minimize a piecewise linear objective function ∑_jF_j where F_j(C_j) corresponds to the cost of the completion of job j at time C_j. This class of function is very large and thus interesting both from a theoretical and practical point of view: It can be used to model total (weighted) completion time, total (weighted) tardiness, earliness and tardiness, etc. We introduce a new Mixed Integer Program (MIP) based on time interval decomposition. Our MIP is closely related to the well‐known time‐indexed MIP formulation but uses much less variables and constraints. Experiments on academic benchmarks as well as on real‐life industrial problems show that our generic MIP formulation is efficient. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

On the exponentially weighted moving variance

MacGregor and Harris (J Quality Technol 25 (1993) 106–118) proposed the exponentially weighted mean squared deviation (EWMS) and the exponentially weighted moving variance (EWMV) charts as ways of monitoring process variability. These two charts are particularly useful for individual observations where no estimate of variability is available from replicates. However, the control charts derived by using the approximate distributions of the EWMS and EWMV statistics are difficult to interpret in terms of the average run length (ARL). Furthermore, both control charting schemes are biased procedures. In this article, we propose two new control charts by applying a normal approximation to the distributions of the logarithms of the weighted sum of chi squared random variables, which are respectively functions of the EWMS and EWMV statistics. These new control charts are easy to interpret in terms of the ARL. On the basis of the simulation studies, we demonstrate that the proposed charts are superior to the EWMS and EWMV charts and they both are nearly unbiased for the commonly used smoothing constants. We also compare the performance of the proposed charts with that of the change point (CP) CUSUM chart of Acosta‐Mejia (1995). The design of the proposed control charts is discussed. An example is also given to illustrate the applicability of the proposed control charts. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

靶场光学测量数据异方差性检验及修正

为了避免靶场光学测量数据异方差性导致的普通最小二乘估计非有效、显著性检验失去意义和模型的预测失效问题,采用了图形分析、Goldfeld-Quandt和Breusch Pagan Godfrey方法检验光学测量数据异方差性,并针对光学测量数据的异方差性提出分段加权最小二乘修正的方法。通过理论分析,对某设备方位角测量数据进行实验验证,取得了残差平方数据、G-Q检验统计数据、BPG检验统计数据和分段加权最小二乘BPG统计数据。结果表明应用图形分析法对光学测量数据进行异方差性检验最直观和简捷,适合存在明显异方差性的检验,G-Q检验法不适用光学测量数据的异方差性检验,BPG检验理论完整且适合光学测量数据的异方差性检验,分段加权最小二乘方法有效合理,消除了异方差性对回归模型的影响。     

制导炸弹滚转通道混合灵敏度鲁棒控制器设计

制导炸弹在大空域飞行过程中受到外界干扰和未建模摄动都较大,为了适应较大摄动,采用混合灵敏度方法来设计鲁棒控制器.首先推导了包含S/T/R的广义受控对象的状态空间模型,将混合灵敏度问题化为标准H∞问题.然后针对混合灵敏度问题中如何选取权函数的关键性问题,讨论了权函数选取的一般原则,提出了权函数选取的一般方法,并尝试给出权函数的一般形式.最后采用该方法对制导炸弹滚转通道进行了控制器设计,仿真结果表明:H∞控制器有较好的鲁棒性能,且比传统PID控制有更好的时域性能.     

应用全站仪综合测量火炮偏离角及俯仰半径

提出一种应用全站仪进行火炮偏离角和俯仰半径的综合测量方法。应用最小二乘原理拟合出火炮俯仰半径,然后解算出火炮偏离角,并用Monte Carlo方法分析了测量结果的精度。结果表明:全站仪高低角和火炮仰角的测量精度均对火炮偏离角和俯仰半径的测量结果无明显影响;全站仪测距精度对火炮俯仰半径测量结果的影响较大;全站仪水平角测量精度对火炮偏离角测量结果的影响明显。该方法在现场操作时需要重点关注全站仪水平观测角和测距的检测精度。     

基于动态窗口的灰色加权填充算法及应用?

为解决复杂系统中单属性缺失数据填充困难问题，提出了基于动态窗口的灰色加权填充算法。该算法通过建立双向灰色预测模型，并采用模型精度评价系数加权填充缺失数据，有效增强了算法的准确性；提出基于灰色模型评价系数反馈的动态伸缩窗口概念，寻找产生最优模型的训练数据序列，使算法具有良好的鲁棒性和适应性。实验结果表明，该方法在RMSE和MA两项指标上均优于传统的双向灰插值、灰插值、多项式插值等方法。