蓝绿激光在水下航行器导航中的应用展望

针对水下航行器导航的薄弱环节,提出运用蓝绿激光的特殊性质,从远程水下航行器自身出发,对以海底地形匹配导航作为惯性导航的补充的导航方式进行了讨论.     

The use of infrared thermographic and GPS topographic surveys to monitor spontaneous combustion of coal tips

Aerial infrared thermography is one of the methods most widely used for monitoring coal tips. Although it offers the advantage of providing wide coverage of the site and clearly displaying areas at risk on the thermal image, it is costly, sensitive to atmospheric conditions and cannot be used to monitor combustion reactions. It is for these reasons that the LAMTI, in liaison with the Charbonnages de France Group, has developed a ground-level method based on a combination of GPS topographic and infrared thermographic surveys that is intended to be more precise and less expensive and may eventually enable combustion reactions to be monitored.     

一种海底规则网格地形的三态值分割算法

目前的虚拟战场环境研究主要集中在陆上环境方面,对海洋战场环境的研究比较少,虚拟海战场环境的基础是真实的地形、地物、地貌等数据.该文采用了一种图像分割算法,对生成的海底规则格网进行快速分割.该方法主要分三个步骤:(1)从海图数据文件中提出散乱的海洋水深数据.(2)利用移动曲面拟合法生成规则格网数据.DEM内插是根据参考点...     

地形特征对粒子滤波导航算法精度影响分析

地形导航是利用飞行器下方地形估计飞行器空间位置的导航方法。由于地形是强非线性模型,因此地形导航可以看作非线性状态估计问题,地形特征直接影响导航精度。在讨论粒子滤波导航算法基础上,重点研究了地形特征对后验概率密度和Cramer-Rao下界的影响,得出了地形梯度和相似度是影响粒子滤波导航算法精度的根本原因,为飞行区域选择、飞行路径规划提供了依据,具有较强的实用性。     

M－QAM系统中载波相位估计量的统计特性分析

本文提出循环类分解和等模类分解法，解决了Ｍ－ＱＡＭ系统中载波相位估计量［１］的统计分析问题。证明了载波相位估计方差除了与加性噪声有关外，它与载波归一化频差的平方成正比；与码型噪声有关，同时，本文的结果简化了对码型噪声的分析模型。     

Optimal parallel algorithms for point-set and polygon problems

In this paper we give parallel algorithms for a number of problems defined on point sets and polygons. All our algorithms have optimalT(n) * P(n) products, whereT(n) is the time complexity andP(n) is the number of processors used, and are for the EREW PRAM or CREW PRAM models. Our algorithms provide parallel analogues to well-known phenomena from sequential computational geometry, such as the fact that problems for polygons can oftentimes be solved more efficiently than point-set problems, and that nearest-neighbor problems can be solved without explicitly constructing a Voronoi diagram.The research of R. Cole was supported in part by NSF Grants CCR-8702271, CCR-8902221, and CCR-8906949, by ONR Grant N00014-85-K-0046, and by a John Simon Guggenheim Memorial Foundation fellowship. M. T. Goodrich's research was supported by the National Science Foundation under Grant CCR-8810568 and by the National Science Foundation and DARPA under Grant CCR-8908092.     

我国主要牧区雪灾遥感监测与评价系统中的数字地形分析及其信息传输

介绍了我国主要收区雪灾遥感监浏中的数字地形信息的计算、存储、格式转换和传输技术。数字地形信息在整个雪灾遥感监浏评价系统中是一种较重要的地理信么，它主要用来对空间信息进行定位控制，并为空间分析操作和应用模型分析提供能反映地理分布特征的信息。对数字地形信息的计算模型、特点及存贮结构进行了较为详细的介绍。数字地形信息是一种栅格数据，而作为雪灾遥感监测评价来统的PC ARC/lNFO空间操作是一种比较完备的地理信息来统，在数据格式上有其自己的特点，数字地形信息只有经过一定的格式转换和数据传输，才能在PC ARC/INFO中进行各类空间操作，达到整个来统设计的目的。如何将数字地形信息转换成PC ARC/INFO能接收的栅格数据结构文件是整个雪灾遥感监浏评价来统中的一个重要外部数据格式转换接口，对该部分内容也进行了详细的介绍。     

Theoretical flow investigations of an all glass evacuated tubular collector

Heat transfer and flow structures inside all glass evacuated tubular collectors for different operating conditions are investigated by means of computational fluid dynamics. The investigations are based on a collector design with horizontal tubes connected to a vertical manifold channel.Three different tube lengths varying from 0.59 m to 1.47 m have been modelled with five different inlet mass flow rates varying from 0.05 kg/min to 10 kg/min with a constant inlet temperature of 333 K. Under these operating conditions the results showed that:

• the collector with the shortest tube length achieved the highest efficiency,

• the optimal inlet flow rate was around 0.4–1 kg/min,

• the flow structures in the glass tubes were relatively uninfluenced by the inlet flow rate,

Generally, the results showed only small variations in the efficiencies. This indicates that the collector design is well working for most operating conditions.     

Minimum cost route for a highway in heterogeneous terrain

This paper shows that the minimum cost route should satisfy the Snell's law of light refraction and this can be done by successive iteration, in either a forward or backward direction. The number of iterations required for full convergence depends on the geometry of the problem and the cost ratio between each of the two neighbouring cost regions.     

Design of interpolation filter for all digital receiver—On the interpolation problem of full response modulation signals

All digital implementation of receiver is a main topic on digital communication recently. The design of interpolation filter is one of the important problems for all digital implementation of receiver. In this paper, for full response linear modulation signal, a interpolation criterion is proposed. An interpolation formula is presented on bandwidth-limited transmission signal. For example, using the raised cosine roll off function as the system pulse response, the feasibility and effectiveness on the interpolation formula are certified by theoretical and numerical analysis. The computer simulation result on 16-QAM signal is given.