GIS支持下的像元地面方向反射几何参数计算

像元地面方向反射几何参数的计算在地物BRDF的遥感反演研究和多角度遥感数字图像的处理中有重要意义.对卫片像元地理位置和地面坡度、坡向以及高度的变化对像元与太阳、像元与卫星的相对几何取向和相互位置的影响进行了讨论.并完成了由任意卫片像元地面太阳入射方位角、入射角、反射方位角(卫星视方位角)、反射角(视角)所组成的方向反射几何参数的计算原理和方法研究.     

基于分形理论的装备维修质量指标影响度分析

针对以往AHP方法的主观性大等不足,从分形的视角出发运用最小二乘回归研究了维修质量的各个因素指标的影响度,建立了基于分形理论的装备维修质量指标影响度分析模型。构建维修质量影响因素指标体系,并在对采集样本数据进行标准化处理的基础上求得了各个考察阶段的维修质量分形维;然后运用最小二乘法求解了分形维与各个因素之间的回归方程,并画出Pareto图加以明确。     

导弹仪器支架有限元分析

根据某导弹仪器支架的结构设计方案 ,利用大型有限元结构分析软件 ANSYS,采用梁、板壳和质量单元描述结构主体 ,用局部刚化模拟仪器支架转角和加强处 ,并对其上的仪器设备和电缆的模拟作了有益的尝试。通过细致的网格划分 ,建立了较为合理的结构有限元动力学计算模型 ,对其进行了结构强度和振动模态分析。计算结果预示和验证了仪器支架的结构性能 ,进而为进行结构振动控制设计提供了理论参考依据。     

用自制起爆药和雷管测定猛炸药的爆轰感度

由于起爆药不能长途运输以及特殊药量的雷管无处购买,就实验室条件下,对常用的起爆药及特殊药量雷管的自制方法及测定猛炸药爆轰感度的结果进行了讨论.     

虚拟现实在声引信设计中的应用

研究复杂的雷弹声引信系统 ,采用传统的仿真方法往往难窥系统全貌。虚拟现实技术构建的人机和谐的仿真环境为研究人员创建身临其境的沉浸感 ,从而启发设计构思、辅助系统测试和评估。本文介绍了声引信虚拟现实系统 ( AFVRS)是基于 PC和局域网 ( LAN)的分布式虚拟现实系统。     

SEM/EDS在案件微量物证鉴定方面的应用

通过一些具体案例 ,叙述了 SEM(扫描电子显微镜 )配合 EDS( X-射线能量色散谱仪 )在案件微量物证分析鉴定方面的应用情况 ,尤其是提出了当以微量油漆物证的微观形态分析、油漆所含无机元素成分的定性、定量分析作为鉴定依据时所注意的几点问题 ,从而为司法部门公正办案提供了必要的科学依据。     

纳米晶W-ThO_2阴极材料的制备及其引弧性能研究

用高能球磨法制备纳米晶W -ThO2 混合粉。用化学处理去除混合粉的杂质和氧化 ,然后进行真空热压烧结制备纳米晶W -ThO2 阴极材料。测量纳米晶阴极材料的起弧电场强度并与传统阴极材料进行比较。结果表明 :纳米晶阴极材料的起弧电场强度远远要比传统阴极材料要低且稳定 ,从而说明纳米晶阴极材料的电子发射能力强 ,起弧和稳弧性能好。     

FAE战斗部爆炸威力评价方法的分析

在对 FAE的爆炸威力评价方法分析和应用的基本上 ,提出对 FAE战斗部爆炸威力评价的观点 :超压 -冲量毁伤准则是毁伤威力普遍适用的评价依据 ,但在国内外目前冲量测试误差较大的情况下 ,用一定条件下的超压 TNT当量评价 FAE战斗部威力 ,实际证明是可靠和实用的方法 .     

Successive interference cancellation for multiuser asynchronousDS/CDMA detectors in multipath fading links

There has been an increasing interest in the use of code-division multiple access (CDMA) in cellular mobile and wireless personal communications. The choice of such multiaccess technique is attractive because of its potential capacity increases and other technical factors such as privacy and multipath rejection capabilities. However, it is well known that the performance of CDMA can be significantly degraded due to cochannel interference (CI) and the near-far effects. We consider the performance of direct-sequence (DS)-based CDMA over fading channels that are modeled as slowly varying Rayleigh-fading discrete multipath channels. Specifically, we propose and analyze an adaptive multistage interference cancellation strategy for the demodulation of asynchronous DS spread-spectrum multiple-access signals. Numerical results show that the proposed multistage detector, which alleviates the detrimental effects of the near-far problem, can significantly improve the system performance     

Reduced storage VQ via secondary quantization

This paper introduces methods for reducing the table storage required for encoding and decoding with unstructured vector quantization (UVQ) or tree-structured vector quantization (TSVQ). Specifically, a low-storage secondary quantizer is used to compress the code vectors (and test vectors) of the primary quantizer. The relative advantages of uniform and nonuniform secondary quantization are investigated. A Linde-Buzo-Gray (LBG) like algorithm that optimizes the primary UVQ codebook for a given secondary codebook and another that jointly optimizes both primary and secondary codebooks are presented. In comparison to conventional methods, it is found that significant storage reduction is possible (typically a factor of two to three) with little loss of signal-to-noise ratio (SNR). Moreover, when reducing dimension is considered as another method of reducing storage, it is found that the best strategy is a combination of both. The method of secondary quantization is also applied to TSVQ to reduce the table storage required for both encoding and decoding. It is shown that by exploiting the correlation among the test vectors in the tree, both encoder and decoder storage can be significantly reduced with little loss of SNR, by a factor of about four (or two) relative to the conventional method of storing test vectors (or test hyperplanes)