Sentiment classification of customer reviews on electric products

A lot of terms represent the speaker\´s evaluation of the item. This evaluative character of the word is called its semantic orientation. The word with positive semantic orientation implies that the item is desirable, and on the other hand, the word with negative semantic orientation implies that the item is not desirable. We propose a method to estimate the semantic orientation(positive or negative) of Japanese products reviews, in which a pair of noun and adjective are selected as the corpus to determine the semantic orientation of the reviews and the semantic orientation scores of the review are calculated according to the corpus. The words which change the semantic orientation of a word called as "contextual valence shifter" such as "not", "very" "quite" are considered in the algorithm to determine the semantic orientation. In order to empirically evaluate the performance of the classification method for Japanese documents, 1400 reviews of two electric products, LCD and MP3 music player, are classified to two categories (positive or negative).