  Web users produce more and more documents expressing opinions. Because these
have become important resources for customers and manufacturers, many have
focused on them. Opinions are often expressed through adjectives with positive
or negative semantic values. In extracting information from users' opinion in
online reviews, exact recognition of the semantic polarity of adjectives is one
of the most important requirements. Since adjectives have different semantic
orientations according to contexts, it is not satisfying to extract opinion
information without considering the semantic and lexical relations between the
adjectives and the feature nouns appropriate to a given domain. In this paper,
we present a classification of adjectives by polarity, and we analyze
adjectives that are undetermined in the absence of contexts. Our research
should be useful for accurately predicting semantic orientations of opinion
sentences, and should be taken into account before relying on an automatic
methods.
