The execution process of satellite-ground clock synchronization and ephemeris uploading in the system is analyzed,as well as their characterized operation and their relationship.Based on the analysis of the scheduling...The execution process of satellite-ground clock synchronization and ephemeris uploading in the system is analyzed,as well as their characterized operation and their relationship.Based on the analysis of the scheduling goal and constraint character,a heuristics rule-based multi-stage link scheduling algorithm was put forward.The algorithm distinguishes the on-off-frontier satellites from the others and schedules them by turns.The paper presented the main flow as well as the detailed design of the rule.Finally based on the current COMPASS global system,some typical resources and constraints are selected to generate an instance.Then the comparison analysis between the heuristics scheduling algorithm and three other traditional scheduling strategies are carried out.The result shows the validity and reasonability of the multi-stage strategy.展开更多
REMEMBER the days when people used to have a phone, a computer and a camera？ I do - simply because it wasn＇t that long ago. However, as technology hurtles along at the speed of light, it might have escaped some peo...REMEMBER the days when people used to have a phone, a computer and a camera？ I do - simply because it wasn＇t that long ago. However, as technology hurtles along at the speed of light, it might have escaped some people＇s attention that all these three devices now come together in the form of a smartphone, There＇s no need to carry all three devices when visiting a tourist site or monument - your handy smartphone can take a picture, log on to the Internet to post your picture on social media, and then use the calling function to tell your friends about the pictures you＇ve just posted.展开更多
传统的数据上报,大多采用发送方作为客户端,向上级服务器发起连接请求,采用主动推送的方式完成数据传输。当电站数量巨大且上报数据种类和通信条件都不尽相同时,这种方式无疑为上级服务器打开了一个后门,带来了一定的安全隐患。提出了...传统的数据上报,大多采用发送方作为客户端,向上级服务器发起连接请求,采用主动推送的方式完成数据传输。当电站数量巨大且上报数据种类和通信条件都不尽相同时,这种方式无疑为上级服务器打开了一个后门,带来了一定的安全隐患。提出了一种接收方发起的电站数据传输控制方法,由上级数据中心发起请求、电站响应并完成数据传送的反向拉动模式,使得中心侧不再暴露通讯端口,降低了中心侧网络遭受攻击的可能性。有此,设计了配套的应用层数据可靠传输协议ADRTP(Application-layer Data Reliable Transport Protocol),通过一系列控制机制和调整最大数据包长度L_(max),提高数据传输的效率。展开更多
基金National Natural Science Foundations of China(Nos.71201171,71501179)
文摘The execution process of satellite-ground clock synchronization and ephemeris uploading in the system is analyzed,as well as their characterized operation and their relationship.Based on the analysis of the scheduling goal and constraint character,a heuristics rule-based multi-stage link scheduling algorithm was put forward.The algorithm distinguishes the on-off-frontier satellites from the others and schedules them by turns.The paper presented the main flow as well as the detailed design of the rule.Finally based on the current COMPASS global system,some typical resources and constraints are selected to generate an instance.Then the comparison analysis between the heuristics scheduling algorithm and three other traditional scheduling strategies are carried out.The result shows the validity and reasonability of the multi-stage strategy.
文摘REMEMBER the days when people used to have a phone, a computer and a camera？ I do - simply because it wasn＇t that long ago. However, as technology hurtles along at the speed of light, it might have escaped some people＇s attention that all these three devices now come together in the form of a smartphone, There＇s no need to carry all three devices when visiting a tourist site or monument - your handy smartphone can take a picture, log on to the Internet to post your picture on social media, and then use the calling function to tell your friends about the pictures you＇ve just posted.
文摘传统的数据上报,大多采用发送方作为客户端,向上级服务器发起连接请求,采用主动推送的方式完成数据传输。当电站数量巨大且上报数据种类和通信条件都不尽相同时,这种方式无疑为上级服务器打开了一个后门,带来了一定的安全隐患。提出了一种接收方发起的电站数据传输控制方法,由上级数据中心发起请求、电站响应并完成数据传送的反向拉动模式,使得中心侧不再暴露通讯端口,降低了中心侧网络遭受攻击的可能性。有此,设计了配套的应用层数据可靠传输协议ADRTP(Application-layer Data Reliable Transport Protocol),通过一系列控制机制和调整最大数据包长度L_(max),提高数据传输的效率。
