* The Austria Center Vienna opened a new two-level exhibition hall this fall. The new facilities provide an additional 66,000 square feet of space that can be used alone or in combination with the existing Hall X.

* Starwood Hotels & Resorts has opened its seventh hotel in Japan: the Yokohama Bay Sheraton Hotel & Towers. Its 398 rooms offer in-room modem connections and two-line international direct dialing phones with voice mail. Meeting facilities accommodate groups from 30 to 1,000 people, and simultaneous interpretation of 12 languages is available.