多传感器多目标无源定位跟踪算法研究

针对多站无源测向交叉定位在复杂环境下会产生大量虚假定位点问题,本文提出了一种对目标进行无源定位跟踪的新方法,即先通过数据聚类,确定目标数量;由此动态建立多模弹性神经网络,去除了大部份虚假点;再通过建立航迹树的方法来动态跟踪目标,去除弹性网络未去除的虚假点.该方法解决了大量虚假点存在的情况下,目标数量的确定难题、弹性网初始化难题及动态剔除虚假点难题,进而有效地解决了多干扰机目标相关、虚假点的剔除问题.仿真分析试验表明:该方法计算量低,弹性网络收敛速率快,目标正确锁定率及虚假点剔除率高.     

基于编码标志点的数码相机三维测量与重构

介绍了利用数码相机作为图像传感器,在物体表面设置编码标志点,通过对编码标志点进行识别和检测,从而确定标志点的空间位置,实现了对物体表面某些特定点三维信息的无接触检测。介绍了其中的关键技术,如标志点的设计与检测、基础矩阵的求解、数码相机参数的标定以及内外参数的捆绑调整等,给出了检测实例并进行了精度验证。实验证明,该方法结构简单,成本低廉,数据采集快,移动方便,检测范围大,可满足三维物体特别是大面积物体空间检测的需求。     

基于显著兴趣点颜色及空间分布的图像检索新方法

提出了一种基于显著兴趣点的图像检索新方法,此方法主要有显著兴趣点检测、基于显著兴趣点的特征描述和相似性度量三个步骤.先使用一个自适应滤波器对图像进行滤波,然后提取显著兴趣点;以显著兴趣点为线索,设计了一种基于显著兴趣点的环形颜色直方图,既利用了显著兴趣点的局部特征,又考虑了显著兴趣点的空间分布结构;用图像间的环形颜色直方图距离来度量图像间的相似性.该检索算法不但保证了对图像旋转、平移鲁棒性,而且克服了传统直方图没有空间位置的缺陷.实验结果表明,该方法对图像检索非常有效.     

On the Blow-up for Quasilinear Parabolic Equations

This article is concerned with the position of blow-up points, blow up rate and an isoperimetric problem for the equation u_t = Δu^m + u^p(p > m ≥ 1) in a convex bounded domain.     

LARGE RANGE ANALYSIS FOR NONLINEAR DYNAMIC SYSTEMS——ELEMENT MAPPING METHOD

This paper presents a new method for global analysis of nonlinear system. By means of transforming the nonlinear dynamic problems into point mapping forms which are single-valued and continuous, the state space can be regularly divided into a certain number of finitely small triangle elements on which the non-linear mapping can be approximately substituted by the linear mapping given by definition. Hence, the large range distributed problem of the mapping fixed points will be simplified as a process for solving a set of linear equations. Still further, the exact position of the fixed points can be found by the iterative technique. It is convenient to judge the stability of fixed points and the shrinkage zone in the state space by using the deformation matrix of linear mapping. In this paper, the attractive kernel for the stationary fixed points is defined, which makes great advantage for describing the attractive domains of the fixed points. The new method is more convenient and effective than the cell mapping methodl^[1]. And an example for two-dimensional mapping is given.     

多镜非稳腔的光线矩阵分析方法

应用光线矩阵方法,求解多镜非稳腔的几何自再现模的共轭像点位置和波面线度的几何放大率。用模的微扰稳定性条件,简捷地确定几何放大率的合理取值和共轭像点位置的稳态解。且讨论了多镜非稳腔的平均单程“衍射损耗”。     

关于跳伞运动员如何安全着陆问题的几点讨论

针对某力学教材中的一道关于跳伞运动员着地动人的思考题进行了讨论,阐明使用降落伞安全着陆以及运动员听做着陆动作遵循的的力学原理,并就相关问题进行了详细讨论,还搜集了有关降落伞的一些资料和实验。     

Spin glass behavior upon diluting frustrated magnets and spin liquids: a Bethe-Peierls treatment

A Bethe-Peierls treatment to dilution in frustrated magnets and spin liquids is given. A spin glass phase is present at low temperatures and close to the percolation point as soon as frustration takes a finite value in the dilute magnet model; the spin glass phase is reentrant inside the ferromagnetic phase. An extension of the model is given, in which the spin glass/ferromagnet phase boundary is shown not to reenter inside the ferromagnetic phase asymptotically close to the tricritical point whereas it has a turning point at lower temperatures. We conjecture similar phase diagrams to exist in finite dimensional models not constraint by a Nishimori's line. We increase frustration to study the effect of dilution in a spin liquid state. This provides a “minimal” ordering by disorder from an Ising paramagnet to an Ising spin glass. Received 9 April 1999 and Received in final form 27 September 1999     

Scalarization of Henig Proper Efficient Points in a Normed Space

In a general normed space equipped with the order induced by a closed convex cone with a base, using a family of continuous monotone Minkowski functionals and a family of continuous norms, we obtain scalar characterizations of Henig proper efficient points of a general set and a bounded set, respectively. Moreover, we give a scalar characterization of a superefficient point of a set in a normed space equipped with the order induced by a closed convex cone with a bounded base.