Alan Sims was a Starfleet officer in the 24th century.
In 2328, the SS Kogin ferried him from Pollux IV Orbital City to Pyris VII Complex. His passenger manifest was accessed by Lieutenant Commander Data aboard the USS Enterprise-D in 2370 by reviewing this data in the commercial transport database. (TNG: "Inheritance", okudagram)
In 2353, he was listed as a Starfleet Operational Support Services officer on a directory placard in Starbase 32, Maxia sector. His office was located in room #75260. (TNG: "Violations", directory)
In 2371, he was listed as a yard engineer at Earth Station McKinley on the dedication plaque of the USS Voyager. (VOY: "Caretaker", dedication plaque) He was still aboard Voyager when the ship was forcefully brought to the Delta Quadrant by the Caretaker.
In 2372, as a lieutenant, he was listed on the Planetary Geosciences Division duty roster. (VOY: "Parturition")
In 2374, he was listed on a crew manifest. (VOY: "The Killing Game", crew manifest)