Transductive Learning with String Kernels for Cross-Domain Text Classification
This work addresses the challenge of domain adaptation in text classification for applications like sentiment analysis, though it is incremental as it builds on existing string kernel methods.
The paper tackles the problem of low accuracy in cross-domain text classification due to limited labeled data in the target domain by proposing a transductive learning algorithm that adapts string kernels to the test set without using ground-truth labels, resulting in significantly better accuracy rates in cross-domain English polarity classification.
For many text classification tasks, there is a major problem posed by the lack of labeled data in a target domain. Although classifiers for a target domain can be trained on labeled text data from a related source domain, the accuracy of such classifiers is usually lower in the cross-domain setting. Recently, string kernels have obtained state-of-the-art results in various text classification tasks such as native language identification or automatic essay scoring. Moreover, classifiers based on string kernels have been found to be robust to the distribution gap between different domains. In this paper, we formally describe an algorithm composed of two simple yet effective transductive learning approaches to further improve the results of string kernels in cross-domain settings. By adapting string kernels to the test set without using the ground-truth test labels, we report significantly better accuracy rates in cross-domain English polarity classification.