Various viewpoints are required to make a survey and a trend analysis on related research. In order to find important problems, especially in unfamiliar field, simple search and clustering is not enough. We have to read most of the articles carefully. The work requires a lot of time and effort. This paper analyzes the sentences that describe the problem using SVM. It turned out the negative words are more effective in discernment than manually selected clue words or the positive words. © 2012 IEEE.
