A feature extraction for latent fault detection and failure modes classification method of board-level package subjected to vibration loadings is presented for prognostics and health management(PHM) of electronics usi...A feature extraction for latent fault detection and failure modes classification method of board-level package subjected to vibration loadings is presented for prognostics and health management(PHM) of electronics using adaptive spectrum kurtosis and kernel probability distance clustering. First, strain response data of electronic components is filtered by empirical mode decomposition(EMD) method based on maximum spectrum kurtosis(SK), and fault symptom vector is developed by computing and reconstructing the envelope spectrum. Second, nonlinear fault symptom data is mapped and clustered in sparse Hilbert space using Gaussian radial basis kernel probabilistic distance clustering method. Finally, the current state of board level package is estimated by computing the membership probability of its envelope spectrum. The experimental results demonstrated that the method can detect and classify the latent failure mode of board level package effectively before it happened.展开更多
基于蒙特卡罗方法模拟、计算并分析了芯片类型、大小、间距、数量以及布局对GaN基发光二极管(LED)集成封装器件COB(Chip On Board)能效的影响。计算结果表明:在芯片间距小于200μm且芯片尺寸或布局等参数相同的条件下,正装LED COB的能...基于蒙特卡罗方法模拟、计算并分析了芯片类型、大小、间距、数量以及布局对GaN基发光二极管(LED)集成封装器件COB(Chip On Board)能效的影响。计算结果表明:在芯片间距小于200μm且芯片尺寸或布局等参数相同的条件下,正装LED COB的能效最低,其次为倒装LED COB,垂直结构芯片的能效最大。当芯片间距大于200μm,3种LED COB的能效趋向饱和。芯片尺寸增加或数量减少可使正装和倒装芯片COB的能效上升,而垂直结构COB的能效基本保持不变。加入图形衬底可提高同样尺寸或布局的正装芯片COB封装器件的能效,但使倒装芯片COB的能效恶化。分析表明:芯片的侧面出光量占整个芯片出光量的比值以及相邻芯片材料的吸收对3种类型COB封装器件的能效有决定性影响。文中还针对正装芯片COB设计了新型菱形芯片布局,与常规正方形芯片布局的COB相比,其能效提高了6.2%。展开更多
用于工业过程控制、通信和航天器上的嵌入式计算机对软、硬件的可靠性要求极高。对于软件较为复杂的嵌入式计算机系统，必须采用高可靠的实时多任务操作系统。处于操作系统和硬件之间的板级支持包(BSP Board Support Packge)的设计是一...用于工业过程控制、通信和航天器上的嵌入式计算机对软、硬件的可靠性要求极高。对于软件较为复杂的嵌入式计算机系统，必须采用高可靠的实时多任务操作系统。处于操作系统和硬件之间的板级支持包(BSP Board Support Packge)的设计是一个复杂的过程，该文介绍了基于VxWorks操作系统的板级支持包以及板级支持包设计、调试中的问题。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51201182)the Aeronautical Science Foundation of China(Grant No.20142896022)
文摘A feature extraction for latent fault detection and failure modes classification method of board-level package subjected to vibration loadings is presented for prognostics and health management(PHM) of electronics using adaptive spectrum kurtosis and kernel probability distance clustering. First, strain response data of electronic components is filtered by empirical mode decomposition(EMD) method based on maximum spectrum kurtosis(SK), and fault symptom vector is developed by computing and reconstructing the envelope spectrum. Second, nonlinear fault symptom data is mapped and clustered in sparse Hilbert space using Gaussian radial basis kernel probabilistic distance clustering method. Finally, the current state of board level package is estimated by computing the membership probability of its envelope spectrum. The experimental results demonstrated that the method can detect and classify the latent failure mode of board level package effectively before it happened.
文摘用于工业过程控制、通信和航天器上的嵌入式计算机对软、硬件的可靠性要求极高。对于软件较为复杂的嵌入式计算机系统，必须采用高可靠的实时多任务操作系统。处于操作系统和硬件之间的板级支持包(BSP Board Support Packge)的设计是一个复杂的过程，该文介绍了基于VxWorks操作系统的板级支持包以及板级支持包设计、调试中的问题。
