The paper duplicate checking system will automatically identify sentences, tables of contents, footnotes and references that are not read, which is not the repetition rate. However, due to the problem of PDF transcoding, it will lead to detection errors and inaccurate playback results.

In most cases, students use word format to check the duplication of HowNet. There are also some students who are worried that others will change or steal their own papers, and use the uploaded pdf format to check the duplication of the website.

If it is only used as a reference for the previous revision of the paper, then there is no need to upload pdf format. Because the detection results in pdf format are easy to make mistakes, the detection results are inaccurate. After the pdf format is uploaded to the duplicate checking system of HowNet, the system of China HowNet needs to be transcoded into text format, which will lead to inaccurate transcoding, poor recognition and easy error.