A data transmission scheduling algorithm for rapid-response earth-observing operations

With the development of rapid-response Earth-observing techniques, the demand for reducing a requirements-tasking-effects cycle from 1 day to hours grows rapidly. For instance, a satellite user always wants to receive requested data in near real-time to support their urgent mis- sions, such as dealing with wildfires, volcanoes, flooding events, etc. In this paper, we try to reduce data transmission time for achieving this goal. The new feature of a responsive satellite is that users can receive signals from it directly. Therefore, the traditional satellite control and operational tech- niques need to be improved to accommodate these changes in user needs and technical upgrading. With that in mind, a data transmission topological model is constructed. Based on this model, we can deal with the satellite data transmission problem as a multi-constraint and multi-objective path- scheduling problem. However, there are many optional data transmission paths for each target based on this model, and the shortest path is preferred. In addition, satellites represent scarce resources that must be carefully scheduled in order to satisfy as many consumer requests as possible. To efficiently balance response time and resource utilization, a K-shortest path genetic algorithm is proposed for solving the data transmission problem. Simulations and analysis show the feasibility and the adaptability of the proposed approach.     

国外水平起降临近空间高速飞机动力的发展

临近空间高速飞机的飞行包线宽广,常规动力不能满足需求,必须采用组合动力。涡轮基组合循环(TBCC)发动机能实现高超声速飞行器水平起降,是临近空间高超声速飞机的最佳动力。首先从TBCC技术研发路线入手,总结出TBCC主要技术研发领域,如高速涡轮基技术、冲压/超燃冲压发动机技术、飞发一体化技术和热防护技术;其次结合TBCC典型研究计划(RTA、FaCET、TriJet、LAPCAT和SR-72),归纳出每个计划的关键技术及进展,并对各方案的未来发展应用进行阐述;最后对TBCC的发展趋势和技术特点进行了总结。     

图说

加勒比海圣马丁岛的朱莉安娜公主国际机场,是世界上最惊险的机场之一,游客将这里的飞机起降方式称为"剃头式"。因为岛屿实在太小,这里的机场跑道只有2400多米,飞机起降时只能紧贴海岸飞行,与游客的头顶只有10米高。在美丽的海滩看硕大的飞机从头顶掠过,这在很多游客看来都是刺激无比的体验。     

微小型螺旋桨滑流内舵面操纵特性实验研究

微小型垂直起降飞行器悬停时往往采用螺旋桨滑流内舵面偏转进行姿态控制,但容易出现操纵力矩不足的问题。本文针对这一问题对微小型静推力状态螺旋桨与带舵面机翼的组合体进行了系统性的实验。通过对实验数据分析,本文指出通过优选螺旋桨几何参数可以改善操纵特性,并得出带舵面机翼不同构型对操纵特性影响的一系列结论,为如何改善此类飞行器悬停时的操纵特性提供了设计参考。     

Fire-X验证机展示无人直升机发展新途径

去年底,诺斯罗普·格鲁门公司与贝尔直升机公司联合研制的Fire-X验证机在亚利桑那州尤马试验场完成了首次全自主飞行.美国海军充分肯定了Fire-X验证机的技术可行性,已经决定利用贝尔407直升机的机体来改装现役"火力侦察兵"无人直升机,从而满足他们目前对舰载中程监视平台的迫切需求.     

立足本职提高图书利用率

对如何提高图书利用率进行思考,从做好采访编目工作,改变藏书布局调整借阅规则,加强图书文献的宣传工作,提高馆员的综合素质等四个方面探讨如何提高图书利用率。     

飞向二十一世纪的F-35

面对21世纪空中力量可能面临的挑战，确保绝对的空中优势，降低战损率，节省研制采购成本，美军在上个世纪90年代提出了研制集隐身、先进航电性能、垂直，短距起降能力和低成本于一体的JSF“联合打击战斗机”计划。     

机场行李自动分拣系统的初步研究

行李输送系统直接关系着机场运行状态，与航班正点运行有着不可分割的关联。行李输送系统的控制模式有自动分拣、半自动分拣和人工分拣等方式。它的分拣模式决定着行李系统以及其它关联设备的利用率以及为旅客服务的质量标准。根据浦东机场一期行李输送系统的构成及其特点和不足来研究一下现代化机场的行李输送系统。