Time-domain airborne electromagnetic(AEM)data are frequently subject to interference from various types of noise,which can reduce the data quality and affect data inversion and interpretation.Traditional denoising met...Time-domain airborne electromagnetic(AEM)data are frequently subject to interference from various types of noise,which can reduce the data quality and affect data inversion and interpretation.Traditional denoising methods primarily deal with data directly,without analyzing the data in detail;thus,the results are not always satisfactory.In this paper,we propose a method based on dictionary learning for EM data denoising.This method uses dictionary learning to perform feature analysis and to extract and reconstruct the true signal.In the process of dictionary learning,the random noise is fi ltered out as residuals.To verify the eff ectiveness of this dictionary learning approach for denoising,we use a fi xed overcomplete discrete cosine transform(ODCT)dictionary algorithm,the method-of-optimal-directions(MOD)dictionary learning algorithm,and the K-singular value decomposition(K-SVD)dictionary learning algorithm to denoise decay curves at single points and to denoise profi le data for diff erent time channels in time-domain AEM.The results show obvious diff erences among the three dictionaries for denoising AEM data,with the K-SVD dictionary achieving the best performance.展开更多
The critical nature of satellite network traffic provides a challenging environment to detect intrusions. The intrusion detection method presented aims to raise an alert whenever satellite network signals begin to exh...The critical nature of satellite network traffic provides a challenging environment to detect intrusions. The intrusion detection method presented aims to raise an alert whenever satellite network signals begin to exhibit anomalous patterns determined by Euclidian distance metric. In line with anomaly-based intrusion detection systems, the method presented relies heavily on building a model of＂normal＂ through the creation of a signal dictionary using windowing and k-means clustering. The results of three signals fi＇om our case study are discussed to highlight the benefits and drawbacks of the method presented. Our preliminary results demonstrate that the clustering technique used has great potential for intrusion detection for non-periodic satellite network signals.展开更多
基金financially supported the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA14020102)the National Natural Science Foundation of China (Nos. 41774125,41530320 and 41804098)the Key National Research Project of China (Nos. 2016YFC0303100,2017YFC0601900)。
文摘Time-domain airborne electromagnetic(AEM)data are frequently subject to interference from various types of noise,which can reduce the data quality and affect data inversion and interpretation.Traditional denoising methods primarily deal with data directly,without analyzing the data in detail;thus,the results are not always satisfactory.In this paper,we propose a method based on dictionary learning for EM data denoising.This method uses dictionary learning to perform feature analysis and to extract and reconstruct the true signal.In the process of dictionary learning,the random noise is fi ltered out as residuals.To verify the eff ectiveness of this dictionary learning approach for denoising,we use a fi xed overcomplete discrete cosine transform(ODCT)dictionary algorithm,the method-of-optimal-directions(MOD)dictionary learning algorithm,and the K-singular value decomposition(K-SVD)dictionary learning algorithm to denoise decay curves at single points and to denoise profi le data for diff erent time channels in time-domain AEM.The results show obvious diff erences among the three dictionaries for denoising AEM data,with the K-SVD dictionary achieving the best performance.
文摘The critical nature of satellite network traffic provides a challenging environment to detect intrusions. The intrusion detection method presented aims to raise an alert whenever satellite network signals begin to exhibit anomalous patterns determined by Euclidian distance metric. In line with anomaly-based intrusion detection systems, the method presented relies heavily on building a model of＂normal＂ through the creation of a signal dictionary using windowing and k-means clustering. The results of three signals fi＇om our case study are discussed to highlight the benefits and drawbacks of the method presented. Our preliminary results demonstrate that the clustering technique used has great potential for intrusion detection for non-periodic satellite network signals.
