二階正規化多標籤線性分類器比較

Abstract

The classification problem appears in many applications such as document classification and web page search. Support vector machine(SVM) is one of the most popular tools used in classification task. One of the component in SVM is the kernel trick. We use kernels to map data into a higher dimentional space. And this technique is applied in non-linear SVMs. For large-scale sparce data, we use the linear kernel to deal with it. We call such SVM as the linear SVM. There are many kinds of SVMs in which different loss functions are applied. We call these SVMs as L1-SVM and L2-SVM in which L1-loss and L2-loss functions are used respectively. We can also apply SVMs to deal with multi-class classification with one-against-one or one-against-all approaches. In this thesis several models such as logistic regression, L1-SVM, L2-SVM, Crammer and Singer, and maximum entropy will be compared in the multi-class classification task.