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合理的评估方法是使得航天飞行器项目的试验论证更具有科学性的有力手段。针对航天器项目试验评估的过程复杂且内容目标不明确的现状,归纳总结了对航天器项目试验的关键技术的遴选和评估指标的确定方法,分析了航天器项目试验数据的特性,选择了差分检测法进行异常值的剔除,基于经典数理统计理论进行两类指标的估计,从而形成了完整的航天器项目试验的评估方法构建,为航天器项目试验的评估验证提供了技术途径。 相似文献
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基于Globalstar和Odyssey两个Walker delta星座,建立星间链路网络,重点分析网络中的不同轨道间星间链的动态特性,特别是与星上跟瞄系统密切相关的俯仰角、方位角和链路长度变化,为卫星网络路由提供依据.对传统的卫星路由策略作了改进,利用卫星系统的冗余覆盖的特性,选择不同策略下的最优路径.针对用户不能忍受通信中断的情况,提出考虑消除中断的路由策略,进行服务质量的分析比较.同时也比较在消除中断的路由策略下,LEO同MEO网络差异之处.消除通信中断是以其它QoS性能下降为代价. 相似文献
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Mahindra Naraine 《Telecommunications Policy》1985,9(2):97-108
The measures that have been introduced to regulate the use of the geostationary orbit are considered by the vast majority of ITU members to be inadequate in their ability to guarantee access to the orbit by all states. In the absence of any powers of enforcement for the ITU, it would seem that ORB-85 may decide that only a long term plan, for the fixed-satellite service, could guarantee access to all states. An alternative is suggested that could meet the objectives of all states. 相似文献
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Chihiro Watanabe Author Vitae Reiko Kondo Author Vitae Author Vitae Haihong Wei Author Vitae 《Technological Forecasting and Social Change》2004,71(4):365-390
Successful innovation and diffusion of technology can be attributed to the identification of the orbit of emerging new technologies that complement or substitute for existing technologies. This dynamism resembles the co-evolution process in an ecosystem. In an ecosystem, in order to maintain sustainable development, the complex interplay between competition and cooperation, typically observed in predator-prey systems, create a sophisticated balance. Given that an ecosystem can be used as a masterpiece system, this sophisticated balance can provide suggestive ideas for identifying an optimal orbit of competitive innovations with complement or substitution dynamism.Prompted by such a sophisticated balance in an ecosystem, this paper analyzes the optimal orbit of competitive innovations and, on the basis of an application of Lotka-Volterra equations, it reviews substitution orbits of Japan's monochrome to color TV system, fixed telephones to cellular telephones, cellular telephones to mobile Internet access service, and analog to digital TV broadcasting. On the basis of substitution orbits analyses, it attempts to extract suggestions supportive to identifying an optimal policy option in a complex orbit leading to expected orbit.Key findings include policy options that are effective in controlling parameters for Lotka-Volterra equations leading to expected orbit. 相似文献
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走向深空--测控通信的发展方向 总被引:10,自引:0,他引:10
在传统的贸易模式下,我国经济和贸易的快速增长带来很多负面效应, 引起“三高一低”,即原材料的高强度消耗、高度污染、对国外市场的高依赖及低附加值,我国需要“三低一高”的新贸易模式来解决这些问题。本文通过图表和数据说明了旧贸易模式的危害及在旧贸易模式下我国处于不利地位,我国需要转变原有的贸易模式,并总结了将旧贸易模式转变为新贸易模式的途径。 相似文献
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针对航天器测控中利用卫星通信转发器实现多站测距进行可行性分析,在扩频测距
帧测距原理的基础上,研究利用卫星转发器对上行测距信号变频转发来实现对星测距,同时
对卫星工程测控与应用系统之间上下行链路功率分配、标校方法、地面测量设备组成原理等
关键技术进行分析论述。该测距方案突破了传统多站测距时受卫星应答机配置数量的限制条
件,实现多站同时测距后,可以提高测距精度和定轨精度,降低对设备测角精度的要求,减
少测轨时间,有效缓解测控设备资源紧张的状况,同时该测距方式还可作为应答方式侧音测
距的有效技术备份手段。 相似文献
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本文重点讨论孤立原子和非孤立原子的原子轨道的简并性和任意性,从某一独特的方面对原子成键现象和键的本质进行阐述,以期使人们对其有更全面的了解. 相似文献