Oslo has an extensive public transport system, with busses, trams, metro, boats, trains and city bikes. The easiest and most efficient way to get around is probably to use the metro system, since both the University and Music Academy are located next to metro stations:
Tickets: Remember to buy a ticket in advance of your travel. You can buy single tickets, a day pass, or a week pass. The best for NIME participants may be to buy a flexi-card (NOK 170), which can be used for 8 travels. Just remember to stamp your ticket in the yellow validation machines on the metro station or on the bus/tram.