Thai Stock News Sentiment Classification using Wordpair Features Ponrudee Netisopakul author Apinan Chattupan author 2015-10 text Proceedings of the 29th Pacific Asia Conference on Language, Information and Computation Hai Zhao editor Shanghai, China conference publication netisopakul-chattupan-2015-thai https://aclanthology.org/Y15-1022/ 2015-10 188 195