Question: What is the approach of previous work?
Answer: 'shallow' naive Bayes, SVM, hierarchical stacked classifiers, bidirectional recurrent neural networks
Alternative answer: BIBREF11 that uses a character level n-gram language model, 'shallow' naive Bayes classifiers BIBREF12, BIBREF8, BIBREF13, BIBREF14, SVMs BIBREF15, BIBREF16 used an SVM with character n-gram, parts of speech tag features and some other engineered features, The winning approach for DSL 2015 used an ensemble naive Bayes classifier, The fasttext classifier BIBREF17, hierarchical stacked classifiers (including lexicons), bidirectional recurrent neural networks BIBREF23 or ensembles of recurrent neural networks BIBREF24