We decided to focus on those features that were successfully used in the past for emotion classification (Strapparava and Mihalcea, 2008).
we use: (1) unigram features obtained from a bag-of-words representation, which are the features typically used by corpusbased methods; and (2) lexicon features, indicating the appartenance of a word to a semantic class defined in manually crafted lexicons, which are often used by knowledge-based methods.