Supplementary note: The student's personal identification code with the number 19 in electronic student status, which is a unified code for the basic information of the personnel in the education system, consists of the type code of 1 0, the citizen's identification number of 18 or the personal identification self-coding of 18.

Personal identity self-coding 18 digit refers to the educational identity number given to the educated individual by the Ministry of Education according to these rules when the educated individual has no citizenship number for the time being and the second generation or original citizenship number is unavailable. Personal identity self-coding (18 bits) is a feature combination code, which consists of a 17-bit digital ontology code and a check code. From left to right, the sequence is six-bit address code, eight-bit date of birth code and three-digit number.