Ensign Hickman was a 24th century Starfleet officer who served in astrophysics aboard the USS Voyager in 2371. In that year, along with the rest of the crew, Hickman was stranded in the Delta Quadrant by the entity known as "the Caretaker."
In 2373, upon entering Borg space, Captain Janeway turned to the personal logs of all of the Starfleet captains who had encountered the Borg. Reading selected passages out loud to Commander Chakotay, Janeway was informed that she had been using the inflections of the individuals whom she was quoting, and that Ensign Hickman did a "passable" impression of Janeway, although Janeway speculated that there was probably a regulation against imitating the captain. (VOY: "Scorpion")
The next year, as speculation began to run rampant aboard Voyager regarding Captain Janeway's actions subsequent to the detection of the Omega molecule, Hickman guessed that they were attempting to seal an opening to fluidic space. (VOY: "The Omega Directive")