Abstract
In the Net News, conflicts among the participants are often observed. It seems that the conflicts are often caused by the difference in the cultural background of the participants. In this paper, we intend to propose a quantitative extraction method of the conflicts. Articles in the Net News can be positioned in tree structures (threads) defined by the referential relation. A thread is treated as a set of samples for the analysis. Each article is distinguished by key word frequencies and they are summarized to principal component scores. Applying this technique to actual Net News threads, we found that when a thread includes conflicts, some scores vibrate with wavelength of two generations in the thread. Also the key of the conflict can be estimated with the meaning of the vibrating principal component. We expect that such a quantitative extraction technique of conflicts is useful for study of the social relation through electronic communication.