Objective To detect unknown network worm at its early propagation stage. Methods On the basis of characteristics of network worm attack, the concept of failed connection flow (FCT) was defined. Based on wavelet packet...Objective To detect unknown network worm at its early propagation stage. Methods On the basis of characteristics of network worm attack, the concept of failed connection flow (FCT) was defined. Based on wavelet packet analysis of FCT time series, this method computed the energy associated with each wavelet packet of FCT time series, transformed the FCT time series into a series of energy distribution vector on frequency domain, then a trained K-nearest neighbor (KNN) classifier was applied to identify the worm. Results The experiment showed that the method could identify network worm when the worm started to scan. Compared to theoretic value, the identification error ratio was 5.69%. Conclusion The method can detect unknown network worm at its early propagation stage effectively.展开更多
The chaotic motion characteristics are expounded by taking the Duffing equation system as an example.The frequency band segmentation ability and the frequency resolution of the orthogonal multiresolution analysis and ...The chaotic motion characteristics are expounded by taking the Duffing equation system as an example.The frequency band segmentation ability and the frequency resolution of the orthogonal multiresolution analysis and the orthogonal wavelet packet analysis are compared.A new orthogonal wavelet packet analysis-based chaos recognition method for chaotic motion characteristics is put forward.The chaotic,random,and periodic motions are identified effectively by use of the subfrequency band energy distribution in the signal spectrum.The characteristic frequency of chaotic motion is thus extracted.展开更多
Vocal cord paralysis can occur as a complication o surgery or anaesthesia,if permanent is a significant clinica problem.Early detection is important to optimize the chance o repair,and avoid complications associated w...Vocal cord paralysis can occur as a complication o surgery or anaesthesia,if permanent is a significant clinica problem.Early detection is important to optimize the chance o repair,and avoid complications associated with an impaired swallow.An algorithm to detect altered vocal cord function was presented based on wavelet packet analysis(WPA) and suppor vector machines(SVM),and compared with the Hoarseness Diagram method(HDm),which was reported as an objective voice quality evaluation approach and could be used for pathological voice discrimination.Experiments using voice signals recorded from subjects before and after the procedure show high classification accuracy with the new algorithm,whereas HDm fails in the detection of a hoarse voice.This finding would help to develop a screening tool to detect the vocal structure damage during surgery.展开更多
基金This work was supported by National "863" programof China (No.2003AA148010) and National Torch Project of China (No.2005EB011484) .
文摘Objective To detect unknown network worm at its early propagation stage. Methods On the basis of characteristics of network worm attack, the concept of failed connection flow (FCT) was defined. Based on wavelet packet analysis of FCT time series, this method computed the energy associated with each wavelet packet of FCT time series, transformed the FCT time series into a series of energy distribution vector on frequency domain, then a trained K-nearest neighbor (KNN) classifier was applied to identify the worm. Results The experiment showed that the method could identify network worm when the worm started to scan. Compared to theoretic value, the identification error ratio was 5.69%. Conclusion The method can detect unknown network worm at its early propagation stage effectively.
基金study was supported by the 7th Younger Teacher Fund of Fok Ying Tung Education Foundation (No.71061).
文摘The chaotic motion characteristics are expounded by taking the Duffing equation system as an example.The frequency band segmentation ability and the frequency resolution of the orthogonal multiresolution analysis and the orthogonal wavelet packet analysis are compared.A new orthogonal wavelet packet analysis-based chaos recognition method for chaotic motion characteristics is put forward.The chaotic,random,and periodic motions are identified effectively by use of the subfrequency band energy distribution in the signal spectrum.The characteristic frequency of chaotic motion is thus extracted.
基金National Natural Science Foundation of China (No.60971016)
文摘Vocal cord paralysis can occur as a complication o surgery or anaesthesia,if permanent is a significant clinica problem.Early detection is important to optimize the chance o repair,and avoid complications associated with an impaired swallow.An algorithm to detect altered vocal cord function was presented based on wavelet packet analysis(WPA) and suppor vector machines(SVM),and compared with the Hoarseness Diagram method(HDm),which was reported as an objective voice quality evaluation approach and could be used for pathological voice discrimination.Experiments using voice signals recorded from subjects before and after the procedure show high classification accuracy with the new algorithm,whereas HDm fails in the detection of a hoarse voice.This finding would help to develop a screening tool to detect the vocal structure damage during surgery.
