Paper duplication checking is based on published literature, including journal papers, conference papers, degree papers and so on. The master's theses and doctoral theses of previous graduates of your university can be found if they have been included in the dissertations database of China Knowledge Network or Wanfang Data Platform. Because of the large number and low academic level, undergraduate graduation thesis is generally not included in the database and will not be found out by the duplicate checking system. But if the repetition rate of your graduation project and seniors is too high, the teacher will see it when defending. So you have to be innovative to pass the defense.