论文标题
通过分层分区和数据依赖分组进行多标记分类
Multilabel Classification by Hierarchical Partitioning and Data-dependent Grouping
论文作者
论文摘要
在现代多标记分类问题中,每个数据实例属于大量类别的少数类。换句话说,这些问题涉及学习非常稀疏的二进制标签向量。此外,在大规模的问题中,标签通常具有一定的(未知)层次结构。在本文中,我们利用标签向量和分层结构的稀疏性将其嵌入使用标签组的低维空间中。因此,我们在较低的维空间中解决了分类问题,然后使用适当定义的举重在原始空间中获得标签。我们的方法建立在(Ubaru&Mazumdar,2017年)的基础上,在该工作中,还探索了小组测试的想法以进行多标签分类。我们首先提出了一种新型的数据依赖性分组方法,在该方法中,我们基于训练实例标签矩阵的低级别非负矩阵分解(NMF),使用组构造。该结构还使我们使用最新结果来开发一种快速预测算法,该算法在标签数中具有对数运行时。然后,我们提出了一种层次分区方法,该方法利用大规模问题的标签层次结构来划分大标签空间并创建较小的子问题,然后可以通过分组方法独立地解决。许多基准数据集的数值结果表明,与其他流行的方法相比,我们提出的方法以明显降低的计算成本来实现竞争精度。
In modern multilabel classification problems, each data instance belongs to a small number of classes from a large set of classes. In other words, these problems involve learning very sparse binary label vectors. Moreover, in large-scale problems, the labels typically have certain (unknown) hierarchy. In this paper we exploit the sparsity of label vectors and the hierarchical structure to embed them in low-dimensional space using label groupings. Consequently, we solve the classification problem in a much lower dimensional space and then obtain labels in the original space using an appropriately defined lifting. Our method builds on the work of (Ubaru & Mazumdar, 2017), where the idea of group testing was also explored for multilabel classification. We first present a novel data-dependent grouping approach, where we use a group construction based on a low-rank Nonnegative Matrix Factorization (NMF) of the label matrix of training instances. The construction also allows us, using recent results, to develop a fast prediction algorithm that has a logarithmic runtime in the number of labels. We then present a hierarchical partitioning approach that exploits the label hierarchy in large scale problems to divide up the large label space and create smaller sub-problems, which can then be solved independently via the grouping approach. Numerical results on many benchmark datasets illustrate that, compared to other popular methods, our proposed methods achieve competitive accuracy with significantly lower computational costs.