浅谈VoIP技术在空管语音交换系统的应用及发展

作者： 郭娜   来源： 厦门科技 年份： 2017 文献类型 ： 期刊 关键词： 多媒体通信   Aviation   VoIP技术   服务模型   实时传输   交换系统   网络层   路由选择   Voice   互联网协议  

描述： 引言民航语音通信系统发展经历了三个阶段,模拟语音通信、PCM(Pulse Code Modulation)语音通信和Vo IP语音。Vo IP(Voice over Internet Protocol)基于互联网协议的语音通信技术从上世纪90年代中期出现之后得到了蓬勃的发展和广泛的应用。随着网络时代的来临,Vo IP以不可比拟的成本优势和便利性迅速在语音通信市场蹿红。EU-

空中互联时代已经来临

作者： 李璇   蓝楠   来源： 航空维修与工程 年份： 2017 文献类型 ： 期刊 关键词： 国际航线   下行速率   汉莎航空   Aviation   卫星网络   卫星通讯技术   即时通讯   卫星通信技术   互联时代   盈利能力  

描述： 空中互联时代已经来临

聚焦达索“猎鹰”客户服务

作者： 李璇   来源： 航空维修与工程 年份： 2017 文献类型 ： 期刊 关键词： 刘丽英   中国市场   机队规模   Aviation   达索   通用航空   制造基础   公务机   Falcon   客户服务  

描述： 聚焦达索“猎鹰”客户服务

NASA与工业界联手开发绿色航空技术

作者： 孙明霞   邹志鹏   来源： 航空发动机 年份： 2017 文献类型 ： 期刊 关键词： 验证机   研究计划   日至   联邦预算   Aviation   燃油费用   联手开发   航空技术   飞机设计   航空航天局  

描述： 2016年初,美国政府提交的2017财年(从2016年10月1日至2017年10月1日)联邦预算申请提案中,一笔达数亿美元的庞大预研资金引起广泛关注,这是美国航空航天局(NASA)1个为期长达10年

持续改进:航空安全的基石

作者： 陈琪   黎明   来源： 大飞机 年份： 2017 文献类型 ： 期刊 关键词： 佩科   Aviation   持续改进   民机   国际航空公司   足球俱乐部   飞机坠毁   航空安全   数据库资料   全球航空  

描述： 据Aviation Safety航空安全数据库资料显示,2015年全球发生16起重大致命民机事故,是1973年以来"最安全的一年"。2016年,虽然全球航空业依然保持很高的安全水平,但也发生了一些值得关注的事件,如巴西沙佩科恩足球俱乐部队员搭乘的飞机坠毁、巴基斯坦国际航空公司一架客机坠毁等。虽然航空运输史上也曾出现过著名的"哈德逊河奇迹",但民机事故始终是人们无法释怀的伤痛。也正是在不断吸取这些教训

中国航空集团总部大厦 中国北京

作者： 暂无 来源： 世界建筑导报 年份： 2017 文献类型 ： 期刊 关键词： 启动时间   项目面积   Aviation   国际工程   竣工时间   中国航空集团   competition   实施方案   中国中元   国际招标  

描述： 项目面积:89 855 m~2启动时间:2008年项目类型:国际招标中标实施方案竣工时间:2015年业主:中国航空集团总部大厦建设指挥部合作方:中国中元国际工程有限公司Acreage:89 855 m~2Begin time:2008Project type:International biding competition-selection buildup scheme Completion time:2015Client:Construction Headquarters of China National Aviation Holding Partner:China IPPR International Engineering Co.,Ltd.

Online lab design for aviation engineering students in higher education: a pilot study

作者： Ng   Davy   Tsz   Kit   来源： Interactive Learning Environments 年份： 2023 文献类型 ： 期刊 关键词： flight   virtual   education   Aviation   simulation   reality   learning   Online   Lab  

描述： There is a strong need for educators to change the way they conduct aviation education to bring up future professionals in the industry. To cope with the COVID-19 challenge, creative online distance learning approaches become necessary. This article shows how an online lab approach offers social and cognitive support for engineering students to sustain their learning. A series of learning activities including flight simulation and virtual tours were held in an online lab setting by aviation professionals and lecturers at a university in Hong Kong to 35 undergraduate engineering students. The online lab encouraged students to apply knowledge into practice and develop their theoretical and conceptual knowledge through activities. Workshops focusing on aviation laboratory education aimed at students’ development of aviation theoretical and technical knowledge, collaborative skills, field-specific, and practical skills. A mixed research method was employed with the use of a motivational survey, teachers’ observation, and semi-structured interviews to understand students’ learning perceptions. This study found that the online laboratory activities could effectively motivate students to learn about aviation and improve their aviation knowledge cognitively and socially. It is recommended for online engineering educators to use lab technologies to teach aviation and related disciplines for future career preparation.

High AOA decoupling control for aircraft based on ADRC

作者： LIU   Junjie   SUN   Mingwei   CHEN   Zengqiang   SUN   Qinglin   来源： Journal of Systems Engineering and Electronics 年份： 2020 文献类型 ： 期刊 关键词： disturbance   allocation   linear   attack(AOA)   decoupling   active   control   observer(LESO)   technology   rejection   extended   high   of   thrust   angle   state   control(ADRC)   Vector  

描述： In this paper, a practical decoupling control scheme for fighter aircraft is proposed to achieve high angle of attack(AOA)tracking and super maneuver action by utilizing the thrust vector technology. Firstly, a six degree-of-freedom(DOF) nonlinear model with 12 variables is given. Due to low sufficiency of the aerodynamic actuators at high AOA, a thrust vector model with rotatable engine nozzles is derived. Secondly, the active disturbance rejection control(ADRC) is used to realize a three-channel decoupling control such that a strong coupling between different channels can be treated as total disturbance, which is estimated by the designed extended state observer. The control surface allocation is implemented by the traditional daisy chain method. Finally,the effectiveness of the presented control strategy is demonstrated by some numerical simulation results.

Application of low-altitude wind shear recognition algorithm and laser wind radar in aviation meteorological services

作者： Xu   Ting     Ma   Xiaoling     Li   Qionghua     Lu   Yan   来源： Open Physics 年份： 2023 文献类型 ： 期刊 关键词： Squares   shear   laser   Aviation   Radar   least   k   neighborhood   fitting   wind   frequency  

描述： Abstract The rapid development of the aviation industry has attracted great attention to aviation safety, and the identification and early warning of low-level wind shear have become crucial. Therefore, it is also necessary to improve the performance of laser wind radar technology and achieve accurate recognition of low-level wind shear. In this regard, this study is based on laser wind radar technology and uses the K-neighborhood frequency method to denoise radar data. And based on the least squares fitting method, two-dimensional synthetic wind shear is obtained, and a low altitude wind shear recognition model based on laser wind radar is constructed. These test results confirm that the correlation coefficient values of the wind speed fitting curve measured by the laser detection radar on sunny, cloudy, and fog days are 0.978, 0.954, and 0.961, respectively. And the correlation coefficient values of wind direction fitting curve are 0.984, 0.982, and 0.952, respectively. On sunny, cloudy, and fog days, the recognition accuracy values of the low-level wind shear recognition model are 85.92, 82.17, and 72.43%, respectively. And the recognition accuracy values of wind analyzer radar are 70.18, 62.57, and 55.89%, respectively. In practical applications, the low-level wind shear recognition model accurately recognizes the occurrence of low-level wind shear. This study has achieved accurate recognition of low-level wind shear and has better performance compared to other existing radars. It has played an important reference role in aviation safety.