BSP树消隐算法的改进研究

BSP树算法是在三维景物空间中实现消隐的一种常见算法.BSP树消隐算法中的遍历算法通常是采用递归来实现,在实时虚拟环境具体实现时会导致很大的系统开销.本文在分析BSP树消隐算法中的BSP树的构造和遍历方法的基础上,以一种基于顺序存储结构的非递归算法来代替通常的递归算法,有效的提高了BSP树的遍历速度,提高了三维景物空间的消隐的生成速度,降低了场景中的景物表面多边形的存储空间,有利于实时虚拟环境中三维景物的快速生成.     

Conceptual design and RCS performance research of shipborne early warning aircraft

In order to improve the survivability of the aircraft,conceptual design and radar cross section（RCS） performance research are done. The CATIA software is used to design the 3D digital model of the shipborne early warning aircraft, and some measures are taken to reduce the RCS characteristics of the early warning aircraft at the same time. Based on the physical optics method and the equivalent electromagnetic flow method,the aircraft＇s RCS characteristics and strength distribution characteristics are simulated numerically, and compared with the foreign advanced shipborne early warning aircraft. The simulation results show that under the X radar band, when the incident wave pitching angle is 0？, compared with the foreign advanced shipborne early warning aircraft, the forward RCS average value of the conceptual shipborne early warning aircraft is reduced to 24.49%, the lateral RCS average value is reduced to 5.04%, and the backward RCS average value is reduced to 39.26%. The research results of this paper are expected to provide theoretical basis and technical support for the conceptual design and the stealth design of the shipborne early warning aircraft.     

广义三角模的近似表示

给出了在理论和应用方面都具有重要意义的连续广义三角模的一种近似表示，这种表示可以“逼近”到事先任意指定的精度。     

利用二元关系核排序

对二元关系核与二元关系闭包两种运算之间关系的性质进行研究，给出了二元关系核在排序方面的两点应用．     

建立薛定谔方程的另一种方法

薛定谔方程是量子力学的重要基本方程，许多量子力学教材都是用微分或算符的方法来建立该方程的．本文将讨论另一种用类比来建立薛定谔方程的方法     

颜色光学在遥感技术中的应用

根据颜色光学基本理论和遥感技术物理基础，计算了用于遥感技术中的地物光谱反射比所表现地物用色谱数据和坐标表示该地物的颜色，使颜色的标号具有标准化，数字化和定量化，分析了地物光谱反射比与遥感图象密度间的关系，设计了用于遥感图象解译的植被遥色谱。     

近场光学中多极展开理论的讨论

介绍了近场光学中多极展开的理论，并且采用非线性量子Ermakov系统的方法求解了Helmholtz方程，讨论了二种特殊情况的基本波函数。     

电流步进法实现低频区RCS可视化计算

基于电流步进法的原理,导出了求解任意理想导体目标在照明区及阴影区感应电流佘式,弥补了物理光学在计算目标阴影面的精确电流的不足。通过对目标表面按照入射雷达波波长进行剖分,可获得散射体表面在离散表示式,利用此感应电流的离散方程组,在入射电磁波方向前向/后向反复迭代,可得到积分电流的唯一值,通过Stratton-Chu积分公式,可得到飞行目标雷达散射截面积(RCS),该方法收敛迅速,适合低频复杂目标计算。计算结果与试验结果吻合良好。     

A Binary Integer Program to Maximize the Agreement Between Partitions

This research note focuses on a problem where the cluster sizes for two partitions of the same object set are assumed known; however, the actual assignments of objects to clusters are unknown for one or both partitions. The objective is to find a contingency table that produces maximum possible agreement between the two partitions, subject to constraints that the row and column marginal frequencies for the table correspond exactly to the cluster sizes for the partitions. This problem was described by H. Messatfa (Journal of Classification, 1992, pp. 5–15), who provided a heuristic procedure based on the linear transportation problem. We present an exact solution procedure using binary integer programming. We demonstrate that our proposed method efficiently obtains optimal solutions for problems of practical size. We would like to thank the Editor, Willem Heiser, and an anonymous reviewer for helpful comments that resulted in improvements of this article.     

光学难点刍议

利用惠更斯、惠更斯非涅尔等原理来阐述学生难以理解的光的干涉、衍射等现象.