Alans

Alans was a Human volcanologist in the late 24th century, an ensign serving in Starfleet. In the early 2360s, he was assigned to the USS Enterprise-D.

In 2365, Alans had to work on a project with Ensigns Hildebrant and Davies, under command of acting ensign Wesley Crusher. (TNG: "Pen Pals")

Alans was played by Whitney Rydbeck.
Alans' age and experience suggests that he may be a scientist who joined Starfleet in later life rather than a recent graduate of Starfleet Academy. Other ensigns who have appeared in similar circumstances include Jana Haines and Davies.