Distributed Integrated Modular Avionics(DIMA)develops from Integrated Modular Avionics(IMA)and realizes distributed integration of multiple sub-function areas.Timetriggered network provides effective support for time ...Distributed Integrated Modular Avionics(DIMA)develops from Integrated Modular Avionics(IMA)and realizes distributed integration of multiple sub-function areas.Timetriggered network provides effective support for time synchronization and information coordination in DIMA systems.However,inconsistency between processing resources and communication network destroys the time determinism benefiting from partitions and time-triggered mechanism.To ensure such time determinism and achieve guaranteed real-time performance,system design should collectively provide a global communication scheme for messages in network domain and a corresponding execution scheme for partitions in processing domain.This paper firstly establishes a general DIMA model which coordinates partitioned processing and time-triggered communication,and then proposes a hybrid scheduling algorithm using Mixed Integer Programming to produce feasible system schemes.Furthermore,incrementally integrating new functions causes upgrades or reconfigurations of DIMA systems and will generate integration cost.To control such cost,this paper further develops an optimization algorithm based on Maximum Satisfiability Problem and guarantees that the scheduling design for upgraded DIMA systems inherit their original schemes as much as possible.Finally,two typical cases,including a simple fully connected DIMA system case and an industrial DIMA system case,are constructed to illustrate our DIMA model and validate the effectiveness of our hybrid scheduling algorithms.展开更多
超声衍射时差(time of flight diffraction,TOFD)法存在接收的缺陷衍射信号能量低、易于被噪声干扰的问题.为了解决这一问题,根据TOFD法检测过程中两相邻测点回波中缺陷信号具强相关性、噪声信号具随机性的特点,在传统小波模极大值(wave...超声衍射时差(time of flight diffraction,TOFD)法存在接收的缺陷衍射信号能量低、易于被噪声干扰的问题.为了解决这一问题,根据TOFD法检测过程中两相邻测点回波中缺陷信号具强相关性、噪声信号具随机性的特点,在传统小波模极大值(waveletmodular maximum,WMM)方法的基础上,提出一种改进的噪声抑制技术.分别利用传统和改进的WMM方法对计算机仿真信号及焊缝实测信号进行处理.结果表明,和传统的WMM方法相比较,改进方法对噪声的抑制更为有效,对不同性质的噪声具有更好的适应性,能够在很大程度上提高缺陷信号的辨识能力.展开更多
基于一维连续小波变换的基桩完整性检测分析方法,通过对应力波信号进行多尺度一维连续小波分解,根据局部模极大值线(LocalM aximum L ine)判断信号的奇异点位置。然后根据奇异点位置确定入射波、缺陷反射波、桩底反射波位置。这种分析...基于一维连续小波变换的基桩完整性检测分析方法,通过对应力波信号进行多尺度一维连续小波分解,根据局部模极大值线(LocalM aximum L ine)判断信号的奇异点位置。然后根据奇异点位置确定入射波、缺陷反射波、桩底反射波位置。这种分析方法可以实现对反射波测试数据更为灵活精细的分析,消除了由实测信号直接判读反射波到达时刻存在的潜在误差。给出了实测桩端部响应信号的分析实例,说明将连续小波变换应用于基桩完整性检测是有效的。展开更多
为迎接光伏电站平价上网的挑战,降低光伏发电的度电成本,提高光伏发电的经济性,光伏电站需要从提高能效和降低成本两方面着手。其中光伏电站不同的拓扑结构会影响电站能效和电站造价水平。参考实际运行的光伏电站案例以及设备的研究进展...为迎接光伏电站平价上网的挑战,降低光伏发电的度电成本,提高光伏发电的经济性,光伏电站需要从提高能效和降低成本两方面着手。其中光伏电站不同的拓扑结构会影响电站能效和电站造价水平。参考实际运行的光伏电站案例以及设备的研究进展,从技术性能和经济性2方面对4种不同拓扑结构进行定量的比较分析。此外,文中着重研究了DC-DC变换器成本变化对系统度电成本(levelized cost of energy,LCOE)的影响。研究结果表明,系统效率高的拓扑结构,并不一定是最经济的解决方案。各种拓扑结构选择要根据具体应用场景综合分析。研究结果对大型光伏电站设计有一定的参考意义。展开更多
基金co-supported by the National Natural Science Foundation of China(No.71701020)the Defense Research Field Foundation of China(No.61403120404)the Civil Aircraft Airworthiness and Maintenance Key Laboratory Fund of Civil Aviation University of China(No.2017SW02).
文摘Distributed Integrated Modular Avionics(DIMA)develops from Integrated Modular Avionics(IMA)and realizes distributed integration of multiple sub-function areas.Timetriggered network provides effective support for time synchronization and information coordination in DIMA systems.However,inconsistency between processing resources and communication network destroys the time determinism benefiting from partitions and time-triggered mechanism.To ensure such time determinism and achieve guaranteed real-time performance,system design should collectively provide a global communication scheme for messages in network domain and a corresponding execution scheme for partitions in processing domain.This paper firstly establishes a general DIMA model which coordinates partitioned processing and time-triggered communication,and then proposes a hybrid scheduling algorithm using Mixed Integer Programming to produce feasible system schemes.Furthermore,incrementally integrating new functions causes upgrades or reconfigurations of DIMA systems and will generate integration cost.To control such cost,this paper further develops an optimization algorithm based on Maximum Satisfiability Problem and guarantees that the scheduling design for upgraded DIMA systems inherit their original schemes as much as possible.Finally,two typical cases,including a simple fully connected DIMA system case and an industrial DIMA system case,are constructed to illustrate our DIMA model and validate the effectiveness of our hybrid scheduling algorithms.
文摘超声衍射时差(time of flight diffraction,TOFD)法存在接收的缺陷衍射信号能量低、易于被噪声干扰的问题.为了解决这一问题,根据TOFD法检测过程中两相邻测点回波中缺陷信号具强相关性、噪声信号具随机性的特点,在传统小波模极大值(waveletmodular maximum,WMM)方法的基础上,提出一种改进的噪声抑制技术.分别利用传统和改进的WMM方法对计算机仿真信号及焊缝实测信号进行处理.结果表明,和传统的WMM方法相比较,改进方法对噪声的抑制更为有效,对不同性质的噪声具有更好的适应性,能够在很大程度上提高缺陷信号的辨识能力.
文摘基于一维连续小波变换的基桩完整性检测分析方法,通过对应力波信号进行多尺度一维连续小波分解,根据局部模极大值线(LocalM aximum L ine)判断信号的奇异点位置。然后根据奇异点位置确定入射波、缺陷反射波、桩底反射波位置。这种分析方法可以实现对反射波测试数据更为灵活精细的分析,消除了由实测信号直接判读反射波到达时刻存在的潜在误差。给出了实测桩端部响应信号的分析实例,说明将连续小波变换应用于基桩完整性检测是有效的。
文摘为迎接光伏电站平价上网的挑战,降低光伏发电的度电成本,提高光伏发电的经济性,光伏电站需要从提高能效和降低成本两方面着手。其中光伏电站不同的拓扑结构会影响电站能效和电站造价水平。参考实际运行的光伏电站案例以及设备的研究进展,从技术性能和经济性2方面对4种不同拓扑结构进行定量的比较分析。此外,文中着重研究了DC-DC变换器成本变化对系统度电成本(levelized cost of energy,LCOE)的影响。研究结果表明,系统效率高的拓扑结构,并不一定是最经济的解决方案。各种拓扑结构选择要根据具体应用场景综合分析。研究结果对大型光伏电站设计有一定的参考意义。
