ISCAS in Opinion Analysis Pilot Task: Experiments with sentimental dictionary based classifier and CRF model

The paper presents our work in the opinion pilot task in NTCIR6 in Chinese. In extracting opinion holders, we applied Conditional Random Field (CRF) model to find the opinion holders as a sequential labeling task, while in determining the subjectivity and the polarity, we adopted a simple empirical algorithms based on the sentimental dictionary to discriminate the subjective sentences from the objective ones and suggest their polarities. Besides the features used in the CRF model and the detailed specification in the machine learning system, the evaluation results and the error analysis will also be presented. Keyword: opinion analysis, Conditional Random Field, sentimental dictionary based classifier.