提出了随机振动结构基于测点动力响应的自相关函数幅值向量(Auto-Correlation Function Amplitude Vector,ACFA)的损伤识别方法.将完好结构在两个随机激励下的两组自相关函数幅值向量之间的互相关系数作为损伤识别的基准值,损伤结构的A...提出了随机振动结构基于测点动力响应的自相关函数幅值向量(Auto-Correlation Function Amplitude Vector,ACFA)的损伤识别方法.将完好结构在两个随机激励下的两组自相关函数幅值向量之间的互相关系数作为损伤识别的基准值,损伤结构的ACFA与完好结构的ACFA之间的互相关系数与基准值相比有明显的降低,由此可以判别结构发生了损伤.计算结构损伤前后各测点自相关函数峰值的变化率,波动程度最大的相邻两个测点对应着损伤单元的两个节点,确定了结构的损伤位置.通过一榀木框架有限元模型验证了该方法的有效性,为研究古建筑木结构的损伤识别与定位提供了理论基础.展开更多
Generalized self-shrinking sequences, simply named the GSS sequences, are novel periodic sequences that have many advantages in cryptography. In this paper, we give several results about GSS sequence's application...Generalized self-shrinking sequences, simply named the GSS sequences, are novel periodic sequences that have many advantages in cryptography. In this paper, we give several results about GSS sequence's application to cryptography. First, we give a simple method for selecting those GSS sequences whose least periods reach the maximum. Second, we give a method for describing and computing the auto-correlation coefficients of GSS sequences. Finally, we point out that some GSS sequences, when used as stream ciphers, have a security weakness.展开更多
文摘提出了随机振动结构基于测点动力响应的自相关函数幅值向量(Auto-Correlation Function Amplitude Vector,ACFA)的损伤识别方法.将完好结构在两个随机激励下的两组自相关函数幅值向量之间的互相关系数作为损伤识别的基准值,损伤结构的ACFA与完好结构的ACFA之间的互相关系数与基准值相比有明显的降低,由此可以判别结构发生了损伤.计算结构损伤前后各测点自相关函数峰值的变化率,波动程度最大的相邻两个测点对应着损伤单元的两个节点,确定了结构的损伤位置.通过一榀木框架有限元模型验证了该方法的有效性,为研究古建筑木结构的损伤识别与定位提供了理论基础.
文摘Generalized self-shrinking sequences, simply named the GSS sequences, are novel periodic sequences that have many advantages in cryptography. In this paper, we give several results about GSS sequence's application to cryptography. First, we give a simple method for selecting those GSS sequences whose least periods reach the maximum. Second, we give a method for describing and computing the auto-correlation coefficients of GSS sequences. Finally, we point out that some GSS sequences, when used as stream ciphers, have a security weakness.
