Network traffic anomalies refer to the traffic changed abnormally and obviously.Local events such as temporary network congestion,Distributed Denial of Service(DDoS)attack and large-scale scan,or global events such as...Network traffic anomalies refer to the traffic changed abnormally and obviously.Local events such as temporary network congestion,Distributed Denial of Service(DDoS)attack and large-scale scan,or global events such as abnormal network routing,can cause network anomalies.Network anomaly detection and analysis are very important to Computer Security Incident Response Teams(CSIRT).But wide-scale traffic anomaly detection requires extracting anomalous modes from large amounts of high-dimensional noise-rich data,and interpreting the modes;so,it is very difficult.This paper proposes a general method based on Principle Component Analysis(PCA)to analyze network anomalies.This method divides the traffic matrix into normal and anomalous subspaces,maps traffic vectors into the normal subspace,gets the distance from detected vector to average normal vector,and detects anomalies based on that distance.展开更多
本文针对大情字井地区复杂地质条件下裂缝预测精度不足的问题,提出了一种地震—微地震联合多尺度裂缝预测技术,探讨该技术在CO_(2)地质碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)注气过程中的应用效果。该技术...本文针对大情字井地区复杂地质条件下裂缝预测精度不足的问题,提出了一种地震—微地震联合多尺度裂缝预测技术,探讨该技术在CO_(2)地质碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)注气过程中的应用效果。该技术通过整合地震数据与微地震监测技术,构建了一种多尺度裂缝预测框架:基于人工智能(Artificial Intelligence,AI)深度学习断层预测大尺度裂缝;采用改进的断层似然属性刻画中尺度裂缝;结合优势频率蚂蚁体属性识别小尺度裂缝,并通过压裂/注气诱发的微地震事件验证预测结果。在松辽盆地大情字井H79区块的应用表明,常规地震预测的裂缝识别符合率仅为66%,而联合预测技术提升至92%以上,该技术显著提高了裂缝预测精度。最后通过注气动态监测进一步验证了气窜路径与预测裂缝网络的一致性。研究结果为复杂岩性油藏的裂缝预测及CCUS注气参数优化提供了重要技术支撑。展开更多
距离向多孔径SAR模式是一种高分辨率的宽测绘带成像模式。反解运算和成像处理是距离向多孔径成像算法的两个部分,两者合理配合使用是实现多孑L径模式高精度成像的关键。该文给出了一种采用变尺度傅里叶变换(Scaled F T,scF T,)算法来实...距离向多孔径SAR模式是一种高分辨率的宽测绘带成像模式。反解运算和成像处理是距离向多孔径成像算法的两个部分,两者合理配合使用是实现多孑L径模式高精度成像的关键。该文给出了一种采用变尺度傅里叶变换(Scaled F T,scF T,)算法来实现成像处理并与反解运算结合的多孔径成像算法。与已有的处理算法比较,该算法存不显著增加计算钉杂席的条件下可获得较高的成像质量。文巾最后给m了仿真结果。展开更多
基金This work was funded by the High-tech Research and Development Program of China(863 Program)under Grant 2006II01Z451.
文摘Network traffic anomalies refer to the traffic changed abnormally and obviously.Local events such as temporary network congestion,Distributed Denial of Service(DDoS)attack and large-scale scan,or global events such as abnormal network routing,can cause network anomalies.Network anomaly detection and analysis are very important to Computer Security Incident Response Teams(CSIRT).But wide-scale traffic anomaly detection requires extracting anomalous modes from large amounts of high-dimensional noise-rich data,and interpreting the modes;so,it is very difficult.This paper proposes a general method based on Principle Component Analysis(PCA)to analyze network anomalies.This method divides the traffic matrix into normal and anomalous subspaces,maps traffic vectors into the normal subspace,gets the distance from detected vector to average normal vector,and detects anomalies based on that distance.
文摘本文针对大情字井地区复杂地质条件下裂缝预测精度不足的问题,提出了一种地震—微地震联合多尺度裂缝预测技术,探讨该技术在CO_(2)地质碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)注气过程中的应用效果。该技术通过整合地震数据与微地震监测技术,构建了一种多尺度裂缝预测框架:基于人工智能(Artificial Intelligence,AI)深度学习断层预测大尺度裂缝;采用改进的断层似然属性刻画中尺度裂缝;结合优势频率蚂蚁体属性识别小尺度裂缝,并通过压裂/注气诱发的微地震事件验证预测结果。在松辽盆地大情字井H79区块的应用表明,常规地震预测的裂缝识别符合率仅为66%,而联合预测技术提升至92%以上,该技术显著提高了裂缝预测精度。最后通过注气动态监测进一步验证了气窜路径与预测裂缝网络的一致性。研究结果为复杂岩性油藏的裂缝预测及CCUS注气参数优化提供了重要技术支撑。
文摘距离向多孔径SAR模式是一种高分辨率的宽测绘带成像模式。反解运算和成像处理是距离向多孔径成像算法的两个部分,两者合理配合使用是实现多孑L径模式高精度成像的关键。该文给出了一种采用变尺度傅里叶变换(Scaled F T,scF T,)算法来实现成像处理并与反解运算结合的多孔径成像算法。与已有的处理算法比较,该算法存不显著增加计算钉杂席的条件下可获得较高的成像质量。文巾最后给m了仿真结果。
