In duplicate checking, self-published papers are usually not regarded as duplicates. This is because the duplicate checking system usually compares different databases and text contents, including web pages, academic journals and conference papers on the Internet. Generally speaking, the duplicate checking system does not compare different papers of the same author, so it usually does not think that its published papers are duplicates.

However, it should be noted that if your paper is quoted by other authors or has a lot of similarities with others' papers, it may be judged as duplication. In addition, different schools or institutions may have different regulations and standards when requesting duplicate checking, so it is necessary to read the relevant requirements of schools or institutions carefully and check and modify them according to their requirements.