Enhanced Hierarchical Classification via Isotonic Smoothing
Hierarchical topic taxonomies have proliferated on theWorldWide Web 5, 18, and exploiting the output space decompositions they induce in automated classification systems is an active area of research. In many domains, classifiers learned on a hierarchy of classes have been shown to outperform those learned on a flat set of classes. In this paper we argue that the hierarchical arrangement of classes leads to intuitive relationships between the corresponding classifiers’ output scores, and that enforcing these relationships as a post-processing step after classification can improve its accuracy. We formulate the task of smoothing classifier outputs as a regularized isotonic tree regression problem, and present a dynamic programming based method that solves it optimally. This new problem generalizes the classic isotonic tree regression problem, and both, the new formulation and algorithm, might be of independent interest. In our empirical analysis of two real-world text classification scenarios, we show that our approach to smoothing classifier outputs results in improved classification accuracy.
Hierarchical Classification Taxonomy Regualrized Isotonic Regression Dynamic Programming
Kunal Punera Joydeep Ghosh
Yahoo! Research 701 First Ave.Sunnyvale, CA 94089 University of Texas at Austin Austin, TX 78712
国际会议
第十七届国际万维网大会(the 17th International World Wide Web Conference)(WWW08)
北京
英文
2008-04-21（万方平台首次上网日期，不代表论文的发表时间）