This research paper describes the design and implementation of the Consultative Committee for Space Data Systems (CCSDS) standards REF _Ref401069962 \r \h \* MERGEFORMAT [1] for Space Data Link Layer Protocol (SDLP). ...This research paper describes the design and implementation of the Consultative Committee for Space Data Systems (CCSDS) standards REF _Ref401069962 \r \h \* MERGEFORMAT [1] for Space Data Link Layer Protocol (SDLP). The primer focus is the telecommand (TC) part of the standard. The implementation of the standard was in the form of DLL functions using C++ programming language. The second objective of this paper was to use the DLL functions with OMNeT++ simulating environment to create a simulator in order to analyze the mean end-to-end Packet Delay, maximum achievable application layer throughput for a given fixed link capacity and normalized protocol overhead, defined as the total number of bytes transmitted on the link in a given period of time (e.g. per second) divided by the number of bytes of application data received at the application layer model data sink. In addition, the DLL was also integrated with Ground Support Equipment Operating System (GSEOS), a software system for space instruments and small spacecrafts especially suited for low budget missions. The SDLP is designed for rapid test system design and high flexibility for changing telemetry and command requirements. GSEOS can be seamlessly moved from EM/FM development (bench testing) to flight operations. It features the Python programming language as a configuration/scripting tool and can easily be extended to accommodate custom hardware interfaces. This paper also shows the results of the simulations and its analysis.展开更多
以欧姆龙公司CP1H型号的PLC为应用背景,设计了基于Host Link FINS协议的PLC设备远程监控系统。该文提出了基于串口的远程通信方案,并且详细分析了Host Link FINS协议的结构和指令格式,用MFC实现了监控软件的设计,完成监控软件与欧姆龙PL...以欧姆龙公司CP1H型号的PLC为应用背景,设计了基于Host Link FINS协议的PLC设备远程监控系统。该文提出了基于串口的远程通信方案,并且详细分析了Host Link FINS协议的结构和指令格式,用MFC实现了监控软件的设计,完成监控软件与欧姆龙PLC的数据通信功能,实现监控软件对PLC的远程监控。经过现场的测试和运行,该监控系统稳定可靠,性能较高。展开更多
城市复杂的建筑环境限制了车辆移动和无线信号自由传播,无线自组网呈现通信链路不稳定和拓扑间歇性连通等特点,传统的无线自组网路由方式无法很好地满足车载自组网(Vehicular Ad Hoc Networks,VANETs)的通信需求,VANETs的虚拟注册为Sybi...城市复杂的建筑环境限制了车辆移动和无线信号自由传播,无线自组网呈现通信链路不稳定和拓扑间歇性连通等特点,传统的无线自组网路由方式无法很好地满足车载自组网(Vehicular Ad Hoc Networks,VANETs)的通信需求,VANETs的虚拟注册为Sybil攻击提供了可能,路由路径不再可靠。针对这些问题,提出一种基于通信链路感知的可信路由协议,对通信链路状态进行量化评估,对节点行为进行信任建模,以链路质量和节点信任值作为新的路由决策依据,缓解因路由空洞、恶意评价等现象造成的影响。仿真结果表明,该方法在少量增加通信开销的情况下,能有效提升分组投递率,降低分组传输时延。展开更多
文摘This research paper describes the design and implementation of the Consultative Committee for Space Data Systems (CCSDS) standards REF _Ref401069962 \r \h \* MERGEFORMAT [1] for Space Data Link Layer Protocol (SDLP). The primer focus is the telecommand (TC) part of the standard. The implementation of the standard was in the form of DLL functions using C++ programming language. The second objective of this paper was to use the DLL functions with OMNeT++ simulating environment to create a simulator in order to analyze the mean end-to-end Packet Delay, maximum achievable application layer throughput for a given fixed link capacity and normalized protocol overhead, defined as the total number of bytes transmitted on the link in a given period of time (e.g. per second) divided by the number of bytes of application data received at the application layer model data sink. In addition, the DLL was also integrated with Ground Support Equipment Operating System (GSEOS), a software system for space instruments and small spacecrafts especially suited for low budget missions. The SDLP is designed for rapid test system design and high flexibility for changing telemetry and command requirements. GSEOS can be seamlessly moved from EM/FM development (bench testing) to flight operations. It features the Python programming language as a configuration/scripting tool and can easily be extended to accommodate custom hardware interfaces. This paper also shows the results of the simulations and its analysis.
文摘以欧姆龙公司CP1H型号的PLC为应用背景,设计了基于Host Link FINS协议的PLC设备远程监控系统。该文提出了基于串口的远程通信方案,并且详细分析了Host Link FINS协议的结构和指令格式,用MFC实现了监控软件的设计,完成监控软件与欧姆龙PLC的数据通信功能,实现监控软件对PLC的远程监控。经过现场的测试和运行,该监控系统稳定可靠,性能较高。
文摘城市复杂的建筑环境限制了车辆移动和无线信号自由传播,无线自组网呈现通信链路不稳定和拓扑间歇性连通等特点,传统的无线自组网路由方式无法很好地满足车载自组网(Vehicular Ad Hoc Networks,VANETs)的通信需求,VANETs的虚拟注册为Sybil攻击提供了可能,路由路径不再可靠。针对这些问题,提出一种基于通信链路感知的可信路由协议,对通信链路状态进行量化评估,对节点行为进行信任建模,以链路质量和节点信任值作为新的路由决策依据,缓解因路由空洞、恶意评价等现象造成的影响。仿真结果表明,该方法在少量增加通信开销的情况下,能有效提升分组投递率,降低分组传输时延。
