首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   58篇
  免费   32篇
  国内免费   24篇
航空   69篇
航天技术   7篇
综合类   2篇
航天   36篇
  2023年   7篇
  2022年   10篇
  2021年   4篇
  2020年   9篇
  2019年   10篇
  2018年   10篇
  2017年   7篇
  2016年   3篇
  2015年   3篇
  2014年   8篇
  2013年   6篇
  2012年   3篇
  2011年   5篇
  2010年   3篇
  2008年   4篇
  2007年   9篇
  2006年   3篇
  2005年   1篇
  2004年   2篇
  2003年   2篇
  2001年   1篇
  2000年   3篇
  1993年   1篇
排序方式: 共有114条查询结果,搜索用时 406 毫秒
61.
In recent years, the application of imaging satellites has entered a completely new stage, with the new demands such as rapid response to emergency events, observation of large-scale regional targets and multivariate data fusion, the multi-autonomous satellite constellation has been proposed. This paper first designs the structure of multi-autonomous satellite constellation, and a centralized-distributed structure is proposed. This structure could improve the dynamic response capacity of the whole constellation. Then, this paper adds adapted filtering mechanism to single autonomous satellite online scheduling algorithm to enhance its performance. This article also pays more attention on task allocation strategies of the master satellite in constellation, and ten different task allocation strategies based on five dimensions are analyzed by simulation experiments. At last, this paper extracts several characteristic features of the regular observation targets and designs a selector based on support vector machine (SVM). This selector could select an appropriate strategy according to the features of each experiment scenario.  相似文献   
62.
基于智能Agent的卫星计划系统协作中间件研究   总被引:1,自引:0,他引:1  
Agent技术是分布式系统领域未来发展的重要方向之一,计划协同系统是航天项目在现有基础条件下提高运作效率的关键所在。本文通过研究国内外的计划系统,提出了基于智能Agent技术的计划协同架构中间件CPSOM方案,并且给出一种实现途径。  相似文献   
63.
This study investigates cooperative guidance problems for multiple missiles with fixed and switching directed communication topologies.A two-step guidance strategy is proposed to realize the simultaneous attack.In the first step,a distributed cooperative guidance law is designed using local neighboring information for multiple missiles to achieve consensus on range-to-go and leading angle.The second step begins when the consensus of multiple missiles is realized.During the second step,multiple missiles disconnect from each other and hit the target using the proportional navigation guidance law.First,based on the local neighboring communications,a sufficient condition for multiple missiles to realize simultaneous attack with a fixed communication topology is presented,where the topology is only required to have a directed spanning tree.Then,the results are extended to the case of switching communication topologies.Finally,numerical simulations are provided to validate the theoretical results.  相似文献   
64.
本文首先分析总结了机场竞争力的形成机理,在此基础上提出了机场竞争力的评价原则,最后,构建了一套包含4个一级指标、16个二级指标和41个三级指标的机场竞争力评价指标体系,旨在通过这套评价体系对机场的竞争力发展水平进行评估,找出机场竞争力发展过程中的优势不足,为机场在市场竞争中提高竞争力水平和核心竞争力提供科学的参考依据.  相似文献   
65.
In the interception engagement,if the target movement information is not accurate enough for the mid-course guidance of intercepting missiles,the interception mission may fail as a result of large handover errors.This paper proposes a novel cooperative mid-course guidance scheme for multiple missiles to intercept a target under the condition of large detection errors.Under this scheme,the launch and interception moments are staggered for different missiles.The earlier launched missiles can obtain a relatively accurate detection to the target during their terminal guidance,based on which the latter missiles are permitted to eliminate the handover error in the mid-course guidance.A significant merit of this scheme is that the available resources are fully exploited and less missiles are needed to achieve the interception mission.To this end,first,the design of cooperative handover parameters is formulated as an optimization problem.Then,an algorithm based on Monte Carlo sampling and stochastic approximation is proposed to solve this optimization problem,and the convergence of the algorithm is proved as well.Finally,simulation experiments are carried out to validate the effectiveness of the proposed cooperative scheme and algorithm.  相似文献   
66.
分布式卫星编队飞行队形保持协同控制   总被引:3,自引:0,他引:3  
针对分布式卫星编队飞行队形保持控制问题提出一种分布式协同控制算法,并给出该协同控制算法与编队卫星星间信息传递拓扑结构之间的关系。该协同控制算法以模型预测控制为基础,利用分布式编队卫星的自然特性以及编队卫星之间的信息传递拓扑结构,采用分布式的算法结构,设计分布式的模型预测协同控制算法。该控制算法是一种在线滚动优化控制算法,同时能够较好地解决存在状态约束、控制输入约束等情形下的各种控制问题。最后通过数值仿真验证了结果的有效性。仿真结果表明,当编队卫星星间信息传递拓扑结构中存在生成树时,提出的分布式协同控制算法能够有效地应用到编队卫星队形保持控制问题上来。  相似文献   
67.
通过企业价值链尤其是企业外部价值链的整合来提高企业的竞争优势是企业界的热门话题,企业外部价值链整合的途径有很多,企业通过参与知识联盟,与联盟伙伴一起进行知识和技术的共享能够有效的整合企业的外部价值链。知识联盟可以有效促进联盟企业的知识共享,提高联盟伙伴的创新能力,降低研发风险。通过参与知识联盟进行价值链整合,企业可以获得差异化竞争优势、规模化经济效应以及协同经济效应。  相似文献   
68.
The continuous growth of air traffic has led to acute airspace congestion and severe delays, which threatens operation safety and cause enormous economic loss. Flight assignment is an economical and effective strategic plan to reduce the flight delay and airspace congestion by reasonably regulating the air traffic flow of China. However, it is a large-scale combinatorial optimization problem which is difficult to solve. In order to improve the quality of solutions, an effective multi-objective parallel evolution algorithm(MPEA) framework with dynamic migration interval strategy is presented in this work. Firstly, multiple evolution populations are constructed to solve the problem simultaneously to enhance the optimization capability. Then a new strategy is proposed to dynamically change the migration interval among different evolution populations to improve the efficiency of the cooperation of populations. Finally, the cooperative co-evolution(CC) algorithm combined with non-dominated sorting genetic algorithm II(NSGA-II) is introduced for each population. Empirical studies using the real air traffic data of the Chinese air route network and daily flight plans show that our method outperforms the existing approaches, multiobjective genetic algorithm(MOGA), multi-objective evolutionary algorithm based on decomposition(MOEA/D), CC-based multi-objective algorithm(CCMA) as well as other two MPEAs with different migration interval strategies.  相似文献   
69.
在我国经济发展的特定阶段,发展劳动密集型产业具有比较优势。但是,严格地说,权衡比较优势是不能只看成本的,还要看效率。而我国劳动密集型产业所表现出来的情况是,伴随着时间的推移,劳动力资源的成本呈上升趋势,劳动力资源的效率则呈下降趋势。这就要求我们必须从战略的高度,科学评价我国的粗放型劳动密集产业的历史地位。  相似文献   
70.
于辉  游骏 《航空工程进展》2022,13(1):168-174
高等学校是航空航天原始创新的重要发源地,在航空航天技术发展和进步中发挥了重要作用。为了分析我国高等学校在航空航天领域的发展情况,以JCR 收录的航空航天工程类期刊为数据源,选取2011—2020年我国高等学校发表论文,利用CiteSpace 软件对航空航天领域的论文发表情况、机构合作关系、关键词共现、关键词聚类等进行可...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号