Yoon is a Forensic Programmer as stated by the information provided after his only quote. He also wrote a book entitled "Life, Instanced." He explains that the first group of AI's were simple and that more complex ones were unavoidable. He is quoted, saying that the differences became extreme.
As a hired forensic programmer, he must be very skilled at writing computer code and other such tasks. He appears to also possess writing abilities, as he is a published author with a book on the subject of Thomas and the other AI's, with other possible, unknown books.
"The initial group possessed simple variations in size and strength. More complex configurations were inevitable. As the error spread, these variations became increasingly extreme."