目前的多类学习方法大多将多类问题转化为二类问题,这样处理除了时间开销大,还存在识别盲区。提出了一种直接进行多类学习的算法multi-SVDD。该算法在考虑大样本和多类样本数据中的类内不平衡现象基础上,首先为每类训练样本进行聚类,根...目前的多类学习方法大多将多类问题转化为二类问题,这样处理除了时间开销大,还存在识别盲区。提出了一种直接进行多类学习的算法multi-SVDD。该算法在考虑大样本和多类样本数据中的类内不平衡现象基础上,首先为每类训练样本进行聚类,根据聚类结果由支持向量数据描述(SVDD,Support Vector Date Description)建立多个最小包围球。根据测试样本到SVDD所建立的最小包围球的距离来确定测试样本属于哪个聚类,最终可判断测试样本属于哪个类。multi-SVDD算法在时空开销上相比最小包围球方法没有明显增长,而实验效果则好于最小包围球方法。展开更多
为了利用ROC曲线下的面积(AUC),更好地评价多类SVM学习效果,提出了MOSMAUC(multi-objective optimizes multiclass SVM based on AUC)算法。该算法采用AUC作为评价标准,利用多目标优化算法作为SVM参数的优化方法,避免优化对象的AUC值过...为了利用ROC曲线下的面积(AUC),更好地评价多类SVM学习效果,提出了MOSMAUC(multi-objective optimizes multiclass SVM based on AUC)算法。该算法采用AUC作为评价标准,利用多目标优化算法作为SVM参数的优化方法,避免优化对象的AUC值过低问题,因为在多类分类学习中任何一个两类分类的AUC值太低,都会影响整体学习的效果。实验结果表明,提出的优化方法改进了算法的学习能力,取得了较好的学习效果。展开更多
There is a tradeoff between generalization capability and computational overhead in multi-class learning. We propose a generative probabilistic multi-class classifier, considering both the generalization capability an...There is a tradeoff between generalization capability and computational overhead in multi-class learning. We propose a generative probabilistic multi-class classifier, considering both the generalization capability and the learning/prediction rate. We show that the classifier has a max-margin property. Thus, prediction on future unseen data can nearly achieve the same performance as in the training stage. In addition, local variables are eliminated, which greatly simplifies the optimization problem. By convex and probabilistic analysis, an efficient online learning algorithm is developed. The algorithm aggregates rather than averages dualities, which is different from the classical situations. Empirical results indicate that our method has a good generalization capability and coverage rate.展开更多
The security of cryptographic systems is a major concern for cryptosystem designers, even though cryptography algorithms have been improved. Side-channel attacks, by taking advantage of physical vulnerabilities of cry...The security of cryptographic systems is a major concern for cryptosystem designers, even though cryptography algorithms have been improved. Side-channel attacks, by taking advantage of physical vulnerabilities of cryptosystems, aim to gain secret information. Several approaches have been proposed to analyze side-channel information, among which machine learning is known as a promising method. Machine learning in terms of neural networks learns the signature （power consumption and electromagnetic emission） of an instruction, and then recognizes it automatically. In this paper, a novel experimental investigation was conducted on field-programmable gate array （FPGA） implementation of elliptic curve cryptography （ECC）, to explore the efficiency of side-channel information characterization based on a learning vector quantization （LVQ） neural network. The main characteristics of LVQ as a multi-class classifier are that it has the ability to learn complex non-linear input-output relationships, use sequential training procedures, and adapt to the data. Experimental results show the performance of multi-class classification based on LVQ as a powerful and promising approach of side-channel data characterization.展开更多
文摘目前的多类学习方法大多将多类问题转化为二类问题,这样处理除了时间开销大,还存在识别盲区。提出了一种直接进行多类学习的算法multi-SVDD。该算法在考虑大样本和多类样本数据中的类内不平衡现象基础上,首先为每类训练样本进行聚类,根据聚类结果由支持向量数据描述(SVDD,Support Vector Date Description)建立多个最小包围球。根据测试样本到SVDD所建立的最小包围球的距离来确定测试样本属于哪个聚类,最终可判断测试样本属于哪个类。multi-SVDD算法在时空开销上相比最小包围球方法没有明显增长,而实验效果则好于最小包围球方法。
文摘为了利用ROC曲线下的面积(AUC),更好地评价多类SVM学习效果,提出了MOSMAUC(multi-objective optimizes multiclass SVM based on AUC)算法。该算法采用AUC作为评价标准,利用多目标优化算法作为SVM参数的优化方法,避免优化对象的AUC值过低问题,因为在多类分类学习中任何一个两类分类的AUC值太低,都会影响整体学习的效果。实验结果表明,提出的优化方法改进了算法的学习能力,取得了较好的学习效果。
基金Project supported by the National Natural Science Foundation of China （No. 61379069）, the Major Program of the National Social Science Foundation of China （No. 12＆ZD231）, and the National Key Technology R＆D Program of China （No. 2014BAK09B04）
文摘There is a tradeoff between generalization capability and computational overhead in multi-class learning. We propose a generative probabilistic multi-class classifier, considering both the generalization capability and the learning/prediction rate. We show that the classifier has a max-margin property. Thus, prediction on future unseen data can nearly achieve the same performance as in the training stage. In addition, local variables are eliminated, which greatly simplifies the optimization problem. By convex and probabilistic analysis, an efficient online learning algorithm is developed. The algorithm aggregates rather than averages dualities, which is different from the classical situations. Empirical results indicate that our method has a good generalization capability and coverage rate.
文摘The security of cryptographic systems is a major concern for cryptosystem designers, even though cryptography algorithms have been improved. Side-channel attacks, by taking advantage of physical vulnerabilities of cryptosystems, aim to gain secret information. Several approaches have been proposed to analyze side-channel information, among which machine learning is known as a promising method. Machine learning in terms of neural networks learns the signature （power consumption and electromagnetic emission） of an instruction, and then recognizes it automatically. In this paper, a novel experimental investigation was conducted on field-programmable gate array （FPGA） implementation of elliptic curve cryptography （ECC）, to explore the efficiency of side-channel information characterization based on a learning vector quantization （LVQ） neural network. The main characteristics of LVQ as a multi-class classifier are that it has the ability to learn complex non-linear input-output relationships, use sequential training procedures, and adapt to the data. Experimental results show the performance of multi-class classification based on LVQ as a powerful and promising approach of side-channel data characterization.
