一种基于时间差分运动检测的改进方法

本文提出了一种基于时间差分运动检测的改进方法。首先计算时间上连续的两帧灰度图像的差分图像；然后，将得到的差分图像通过低通滤波和二值化处理；最后，利用图像序列中的多帧灰度图像计算得到一组二值图像，通过对二值图像进行像素的算术运算，提取出运动目标区域。实验结果表明：这种方法是有效的。     

机场离港过程的仿真研究

以往对机场进离港系统运行的研究通常只停留在系统输出流量的分析上。提出一种基于离散事件动态系统理论(DEDS)的机场离港过程排队论模型，结合统计中的非参数检验方法确定模型的参数，实现离港过程的仿真。同时利用这种方法，对离港过程的各阶段进行分析，得出了在简化模型下各阶段的效率。     

USE OF GENETIC ALGORITHMS TO SEQUENCE THE MACHINING OPERATIONS OF PARTS

ＵＳＥＯＦＧＥＮＥＴＩＣＡＬＧＯＲＩＴＨＭＳＴＯＳＥＱＵＥＮＣＥＴＨＥＭＡＣＨＩＮＩＮＧＯＰＥＲＡＴＩＯＮＳＯＦＰＡＲＴＳＷＡＮＧＸｉｙａｎｇ（王细洋）（ＮａｎｃｈａｎｇＩｎｓｔｉｔｕｔｅｏｆＡｅｒｏｎａｕｔｉｃｓＴｅｃｈｎｏｌｏｇｙ,３３００３４,...     

Introducing the law games: Predicting legal liability and fault in satellite operations

Over recent times there has been a rise in the number of objects placed into Earth orbit. With various countries licensing a number of large constellations, the orbital population is set to increase dramatically. A significant number of technical advances have facilitated this and, in the UK and elsewhere, this has been matched by the updating of legislation and an increased policy focus on the need for increased space surveillance and tracking. The rise of large constellations coupled with an increasing number of experimental techniques such as active debris removal or on-orbit servicing procedures means that establishing fault will be crucial if litigation is to be successful. In doing this, any legal proceedings will look at both norms of behaviour, deviation from which will point towards fault and the types and standard of evidence that will be required.This paper will outline these problems in detail. It will be proposed that what is required to map out the contours of liability are both codification of the norms for satellite operations and clarity on protocols for evidence gathering in cases where fault may be contested in orbital operations. This discussion will identify that a way in which this could be achieved is by the use of “space law games”. These are simulations, similar to military war games, in which fictional scenarios could highlight some of the key legal issues that might need to be dealt with. The paper will outline some of the ways in which the law games might work and pose questions as to what data and other considerations will be needed to make such simulations meaningful.     

基于改进YOLOv3网络的遥感目标快速检测方法

针对将来卫星在轨实时目标检测需求,且在其内存和算力都受限的条件下,提出一种改进的YOLOv3,利用轻量化网络代替YOLOv3的特征提取网络,实现遥感目标的高效检测。在目标检测精度相近的情况下,改进模型参数相比原先降低了1.5倍,计算量降低了3.3倍。同时提出了一种基于交并比的迭代聚类算法,分别在YOLOv3和改进YOLOv3上实现了7.0%和2.3%的平均精度均值(mAP)提升。实验表明:改进模型的检测速度最快能达到101 frame/s,当其mAP比YOLOv3高6%时,检测速度仍是YOLOv3的1.6倍。本文提出的改进YOLOv3是一种高效遥感目标检测方法,为未来星上应用打下基础。     

A pre-generated matrix-based method for real-time robotic drilling chatter monitoring

Currently, due to the detrimental effects on surface finish and machining system, chatter has been one crucial factor restricting robotic drilling operations, which improve both quality and efficiency of aviation manufacturing. Based on the matrix notch filter and fast wavelet packet decomposition, this paper presents a novel pre-generated matrix-based real-time chatter monitoring method for robotic drilling. Taking vibration characteristics of robotic drilling into account, the matrix notch filter is designed to eliminate the interference of spindle-related components on the measured vibration signal. Then, the fast wavelet packet decomposition is presented to decompose the filtered signal into several equidistant frequency bands, and the energy of each sub-band is obtained. Finally, the energy entropy which characterizes inhomogeneity of energy distribution is utilized as the feature to recognize chatter on-line, and the effectiveness of the presented algorithm is validated by extensive experimental data. The results show that the proposed algorithm can effectively detect chatter before it is fully developed. Moreover, since both filtering and decomposition of signal are implemented by the pre-generated matrices, calculation for an energy entropy of vibration signal with 512 samples takes only about 0.690 ms. Consequently, the proposed method achieves real-time chatter monitoring for robotic drilling, which is essential for subsequent chatter suppression.     

基本维修作业工时的数据处理

根据基本维修作业时间的统计分析特点,提出了基本维修作业工时数据的处理方法。该方法明确了维修作业工时数据采集后的筛选和补充方法,按照数理统计方法处理数据的一般流程,给出了本处理方法中的样本数据常用统计量,阐述了基本维修作业工时数据分布的确定方法,提出了基本维修作业工时的计算方法和评价原则。该方法可以显著提高数据的有效性和可信性,处理后的采样数据主要用于建立基本维修作业工时数据库,奠定数字化维修作业平台建设的基础。     

试飞科目的最优排序问题研究

以试飞科目间总的过渡耗油、耗时最省为性能指标，在建立过渡耗油、耗时计算数学模型的基础上，应用“旅行推销员”问题的ＥＡＳＴＭＡＮ解法及最近相邻点启发性解法两种方法对试飞科目的最优排序问题进行了研究。分析了两种方法的适用范围及限制条件，ＥＡＳＴＭＡＮ解法适用于起点和终点为同一科目的问题，最近相邻点启发性解法则是一种适用于开环问题的工程解法。仿真结果表明，通过合理安排试飞科目次序，可节省试飞耗油，耗时，     

基于极大代数的离港航班优化调度

改变以往采用的排队论和线性规划等方法，用极大代数理论研究了航班调度优化问题，将进离港系统的非线性转化为极大代数意义下的线性，结合离散事件动态系统理论(DES)的摄动分析法、鲁棒分析法，论证了不同机型排列对系统性能的影响?运用这一方法，实现了对机型排列的寻优，为科学的航班调度提供了定量的参考：