Hownet: Hownet judges whether a paper is duplicated or plagiarized according to the fact that a sentence is repeated continuously by more than 13 characters, and there is also a 5% threshold for the cited content of the paper.
VIP: VIP is to judge whether a paper is repeated or plagiarized according to a sentence repeated for more than 8 characters.
Paper Free: Paper Free's paper similarity detection is to compare the paper with the database in the system and calculate the similarity of the paper according to the repetition of more than 13 characters.
No matter what kind of duplicate checking system, the similarity of the paper is obtained by comparing the content in the paper with the content in the database. Therefore, the similarity of the paper depends on the specific content of the paper and the threshold setting of the duplicate checking system used.