弱拓扑下集值最优化问题的通有稳定性

用函数的上图象之间的Hausdoff距离定义最优化问题目标函数间的距离。在此弱拓扑下研究定义在紧距离空间上具有普遍意义的最优化问题的稳定性;指出在Baire分类意义下大多数这类问题的解是通有稳定的。     

基于期望系统噪声的自适应机动目标跟踪研究

状态估计是目标跟踪中的基本问题,也是目标跟踪的一个难点。首先对标准IMM算法的优缺点进行了论述,针对其缺点和不足,提出了基于期望系统噪声模型（MIMM）的自适应多模型算法,该算法能有效地对机动目标的状态进行自适应估计。仿真结果表明,该算法比标准的IMM算法有较好的改善。     

基于二阶锥规划的MIMO雷达稳健自适应波束形成

针对MIMO雷达自适应波束形成中期望目标导向矢量的失配问题,提出了一种基于二阶锥规划(SOCP)的稳健自适应波束形成算法。该算法首先将1个MN维(M,N分别为发射和接收阵元数)的权矢量分解成2个低维(1个M维和1个N维)权矢量的Kronecker积,然后分别限制实际的目标发射导向矢量和目标接收导向矢量与假定的导向矢量之间的误差范数的边界,通过优化最差性能,利用SOCP求得分解后的2个权矢量,最后再合成原权矢量。通过降维处理,算法在保证波束形成器性能的基础上,有效地降低了运算复杂度。仿真结果验证了算法的有效性。     

采用多种群搜索策略的微粒群算法调整消磁绕组

目前,常用的消磁系统调整方法一般都是针对舰艇磁场进行的,而较少考虑磁场梯度。为改善舰艇的磁隐身性能,应当同时考虑两者的有效衰减,由此确定的电流优化调整问题为多目标优化问题。为解决该问题,首先采用一种基于多种群搜索策略的微粒群算法分别求解两类目标函数的最优值,并将这两类最优值作为目标函数的归一化常数,然后选取一组适当的权重将多目标优化问题转化为单目标优化问题,并采用多种群微粒群算法求解该单目标优化问题。最后,采用一个典型的消磁系统优化调整问题来验证方法的有效性。实验结果表明:该方法不但能够实现舰船磁信号的削减,同时还能有效抑制舰船磁信号的波动。     

声尾流自导鱼雷导引策略仿真与优化

在分析尾流几何模型及其气泡分布密度的规律的基础上,首先建立了较贴近实际的尾流声学仿真模型。其次,按照尾流自导检测流程,基于反射系数推导了尾流层及海面气泡层的回声级模型,由此建立了鱼雷声学自导检测模型。随后,根据研究需要设计了基于鱼雷作战使用评估理论的声尾流自导鱼雷仿真系统,该系统能够真实模拟尾流自导系统工作过程及鱼雷水下运动过程。最后,以该仿真系统为依托,实现了声尾流自导鱼雷应对空穴或断层的修正导引策略的仿真优化。应用结果表明:该研究对于尾流自导鱼雷导引策略优化和尾流自导仿真方法研究具有实际应用价值。     

用于目标跟踪的自适应广义调频波形设计算法

提出了一种用于雷达目标跟踪的自适应广义调频波形设计算法。该算法根据跟踪器的动态需求,以广义调频信号为样板波形自适应设计下一时刻的发射波形,其目的是使预测的目标跟踪均方误差最小化,并假定高信噪比条件,且目标跟踪运动模型和观测模型均为线性。利用与某一波形相对应的克拉美-罗下限(CRLB)以及卡尔曼滤波器,通过最小化预测的跟踪均方误差来实现广义调频波形的自适应设计。仿真结果表明:在信噪比相同的情况下,与使用固定参数、自适应参数的线性调频波形设计算法相比,所提出的算法能够获得更低的目标跟踪均方误差。     

Efficiency of equilibria in restricted uniform machine scheduling with total weighted completion time as social cost

In the last decade, there has been much progress in understanding scheduling problems in which selfish jobs aim to minimize their individual completion time. Most of this work has focused on makespan minimization as social objective. In contrast, we consider as social cost the total weighted completion time, that is, the sum of the agent costs, a standard definition of welfare in economics. In our setting, jobs are processed on restricted uniform parallel machines, where each machine has a speed and is only capable of processing a subset of jobs; a job's cost is its weighted completion time; and each machine sequences its jobs in weighted shortest processing time (WSPT) order. Whereas for the makespan social cost the price of anarchy is not bounded by a constant in most environments, we show that for our minsum social objective the price of anarchy is bounded above by a small constant, independent of the instance. Specifically, we show that the price of anarchy is exactly 2 for the class of unit jobs, unit speed instances where the finite processing time values define the edge set of a forest with the machines as nodes. For the general case of mixed job strategies and restricted uniform machines, we prove that the price of anarchy equals 4. From a classical machine scheduling perspective, our results establish the same constant performance guarantees for WSPT list scheduling. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

基于Gauss伪谱法和直接打靶法结合的月球定点着陆轨道优化

将一种求解最优控制问题的新方法—高斯伪谱法( Gauss Pseudospectral Method-GPM)和传统的直接打靶法有效结合,对月球着陆器定点软着陆轨道快速优化问题做出了研究.推导了高精度模型下着陆动力学方程.针对优化方法各自的特点和多约束条件下最优月球软着陆轨道设计的难点,提出了问题求解的串行优化策略:将控制变量和终端时间一同作为优化变量,同时离散控制变量与状态变量,取较少的Gauss节点,利用GPM求解初值,初值的求解采用从可行解到最优解的串行优化策略;在Gauss节点上离散控制变量,利用直接打靶法求解精确最优解.仿真结果表明,本文提出的轨道优化方法具有较强的鲁棒性和快速收敛性.     

基于直接数据域自适应算法的相干信号DOA估计

利用直接数据域自适应算法的稳态权值代替噪声子空间构建空间谱,构造了一种超分辨波达方向(DOA)估计方法.为了解决谱峰搜索时的伪峰问题,采用参考阵元轮换得到多组线性无关稳态权值,逼近噪声子空间,能有效去除伪峰.针对相干信号的DOA估计,进一步提出了直接数据域取对称共轭向量的解相干方法.相比子空间分解类算法,本文算法不需估计信号源数目和协方差矩阵、不需特征分解,复杂度仅为O(MP),同时能有效完成解相干处理.     

Minimum deterrence and missile defenses: what's new,what's true,what's arguable

Minimum deterrence is a compromise, or halfway house, between nuclear abolition or nearly zero and assured destruction, the dominant paradigm for strategic nuclear arms control during and after the cold war. Minimum deterrence as applied to the current relationship between the United States and Russia would require downsizing the numbers of operationally deployed long-range nuclear weapons to 1000, or fewer, on each side. More drastic bilateral Russian–American reductions would require the cooperation of other nuclear weapons states in making proportional reductions in their own arsenals. In addition, US plans for European-based and global missile defenses cause considerable angst in Russia and threaten to derail the Obama “reset” in Russian–American relations, despite the uncertainties about current and plausible future performances of missile defense technologies.