This paper investigates the chaotification problem of a stable continuous-time T S fuzzy system. A simple nonlinear state time-delay feedback controller is designed by parallel distributed compensation technique. Then...This paper investigates the chaotification problem of a stable continuous-time T S fuzzy system. A simple nonlinear state time-delay feedback controller is designed by parallel distributed compensation technique. Then, the asymptotically approximate relationship between the controlled continuous-time T-S fuzzy system with time-delay and a discrete-time T-S fuzzy system is established. Based on the discrete-time T-S fuzzy system, it proves that the chaos in the discrete- time T-S fuzzy system satisfies the Li-Yorke definition by choosing appropriate controller parameters via the revised Marotto theorem. Finally, the effectiveness of the proposed chaotic anticontrol method is verified by a practical example.展开更多
针对复合电能质量扰动检测算法实时性差、时频分辨率低的问题,提出了一种基于改进自适应S变换(improved adaptive S transform, IAST)的电能质量扰动实时检测方法。构建全局自适应高斯窗作为IAST的核函数,可随检测频率变化自适应调整窗...针对复合电能质量扰动检测算法实时性差、时频分辨率低的问题,提出了一种基于改进自适应S变换(improved adaptive S transform, IAST)的电能质量扰动实时检测方法。构建全局自适应高斯窗作为IAST的核函数,可随检测频率变化自适应调整窗函数有效窗长及频谱,避免为提高时频分辨率频繁切换窗口参数,降低算法复杂度。以增强信号能量集中度为参数调优目标选取窗口参数,确保对各类扰动的精确时频定位。采用自动阈值法确定实际扰动信号的主频点,并对主频点进行时频变换,进一步提高算法执行效率。仿真和实测结果表明,相比于现有复合电能质量扰动检测算法,该检测方法实时性好、时频分辨能力强、计算复杂度低,适用于复杂电能质量扰动实时准确检测。展开更多
时频分析是气藏烃类检测的常用手段,常规时频分析手段存在时频谱模糊化的问题,难以满足高精度分析的要求。同步挤压S变换(Synchrosqueezing S Transform,SSST)通过对时频能量的重新挤压,能获得更高的时频分辨率。针对同步挤压S变换处理...时频分析是气藏烃类检测的常用手段,常规时频分析手段存在时频谱模糊化的问题,难以满足高精度分析的要求。同步挤压S变换(Synchrosqueezing S Transform,SSST)通过对时频能量的重新挤压,能获得更高的时频分辨率。针对同步挤压S变换处理实际三维地震资料时计算量大的问题,提出采用OpenMP并行计算技术提高计算效率,测试表明加速效果显著。结合大牛地气田的实际地质背景,建立了典型的煤层气地质模型,用SSST分析了30 Hz地震子波下该地质模型的非稳态地震正演响应的时频特征,结果表明,可基于时频特征预测气田8#煤层的含气性。在此基础上,使用SSST对大牛地气田某小区的8#煤层含气富集区进行了预测,指导了某风险探井的部署,该井煤层钻遇率82.9%,实钻井的气测全烃钻遇情况和生产情况证实了SSST在煤层含气富集区地震信号频变信息检测的有效性,为非常规气藏开发提供了技术支撑,应用潜力大。展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 60904101,60972164 and 60904046)the Fundamental Research Funds for the Central Universities (Grant No. N090404009)the Research Foundation of Education Bureau of Liaoning Province,China (Grant No. 2009A544)
文摘This paper investigates the chaotification problem of a stable continuous-time T S fuzzy system. A simple nonlinear state time-delay feedback controller is designed by parallel distributed compensation technique. Then, the asymptotically approximate relationship between the controlled continuous-time T-S fuzzy system with time-delay and a discrete-time T-S fuzzy system is established. Based on the discrete-time T-S fuzzy system, it proves that the chaos in the discrete- time T-S fuzzy system satisfies the Li-Yorke definition by choosing appropriate controller parameters via the revised Marotto theorem. Finally, the effectiveness of the proposed chaotic anticontrol method is verified by a practical example.
文摘针对复合电能质量扰动检测算法实时性差、时频分辨率低的问题,提出了一种基于改进自适应S变换(improved adaptive S transform, IAST)的电能质量扰动实时检测方法。构建全局自适应高斯窗作为IAST的核函数,可随检测频率变化自适应调整窗函数有效窗长及频谱,避免为提高时频分辨率频繁切换窗口参数,降低算法复杂度。以增强信号能量集中度为参数调优目标选取窗口参数,确保对各类扰动的精确时频定位。采用自动阈值法确定实际扰动信号的主频点,并对主频点进行时频变换,进一步提高算法执行效率。仿真和实测结果表明,相比于现有复合电能质量扰动检测算法,该检测方法实时性好、时频分辨能力强、计算复杂度低,适用于复杂电能质量扰动实时准确检测。
文摘时频分析是气藏烃类检测的常用手段,常规时频分析手段存在时频谱模糊化的问题,难以满足高精度分析的要求。同步挤压S变换(Synchrosqueezing S Transform,SSST)通过对时频能量的重新挤压,能获得更高的时频分辨率。针对同步挤压S变换处理实际三维地震资料时计算量大的问题,提出采用OpenMP并行计算技术提高计算效率,测试表明加速效果显著。结合大牛地气田的实际地质背景,建立了典型的煤层气地质模型,用SSST分析了30 Hz地震子波下该地质模型的非稳态地震正演响应的时频特征,结果表明,可基于时频特征预测气田8#煤层的含气性。在此基础上,使用SSST对大牛地气田某小区的8#煤层含气富集区进行了预测,指导了某风险探井的部署,该井煤层钻遇率82.9%,实钻井的气测全烃钻遇情况和生产情况证实了SSST在煤层含气富集区地震信号频变信息检测的有效性,为非常规气藏开发提供了技术支撑,应用潜力大。
