J. Ryan, PhD, was a 29th century doctor from the University of Copernicus who was a member of the Temporal Integrity Commission. Her work with the Commission included the development of the USS Relativity. (VOY: "Relativity")
This character was only mentioned in writing.
Ryan's name was seen on the dedication plaque seen on the bridge of the Relativity. He was named after Voyager actress Jeri Ryan.