  Levering data on social media, such as Twitter and Facebook, requires
information retrieval algorithms to become able to relate very short text
fragments to each other. Traditional text similarity methods such as tf-idf
cosine-similarity, based on word overlap, mostly fail to produce good results
in this case, since word overlap is little or non-existent. Recently,
distributed word representations, or word embeddings, have been shown to
successfully allow words to match on the semantic level. In order to pair short
text fragments - as a concatenation of separate words - an adequate distributed
sentence representation is needed, in existing literature often obtained by
naively combining the individual word representations. We therefore
investigated several text representations as a combination of word embeddings
in the context of semantic pair matching. This paper investigates the
effectiveness of several such naive techniques, as well as traditional tf-idf
similarity, for fragments of different lengths. Our main contribution is a
first step towards a hybrid method that combines the strength of dense
distributed representations - as opposed to sparse term matching - with the
strength of tf-idf based methods to automatically reduce the impact of less
informative terms. Our new approach outperforms the existing techniques in a
toy experimental set-up, leading to the conclusion that the combination of word
embeddings and tf-idf information might lead to a better model for semantic
content within very short text fragments.
