Starbase 384
In 2367, while exploring a cavern on Alpha Onias III, Commander William T. Riker was rendered unconscious by gases. While unconscious, neural scanners scanned Riker's brain. The scanners used elements of Riker's reality and constructed a holodeck simulation with those elements interspersed throughout, so that it felt real to him. What Riker wanted, the scanners made possible.
In one of these simulations, on stardate 49472, Captain Riker, the commanding officer of the USS Titan, was ordered to provide tactical support for Starbase 384, abbreviated as SB384, which was located near the Federation-Romulan border. In 2383, this starbase was mentioned in Riker's service record that was on display in his quarters on the Enterprise-D. (TNG: "Future Imperfect", okudagram)