By plane:

The nearest airport with international connections is Leipzig Airport. You can book a shuttle service (on the registration form) that will bring you from the airport to the hotel.
By train:

From the train station Jena-Paradies, you can take a taxi (see downtown map) to your hotel. The hotel IBIS is about 300 m from the train station, so you could also walk to this place.
From the train station Jena-West, beside a taxi you can also use a bus, which is either waiting in front of the station or running from a stop about 100 m to the left. You can use every bus, and pay inside the bus. It is one station to downtown ("Stadtzentrum"), which is also the final destination. This bus stop is less than 50 m from the hotel IBIS. The distance from the station to the IBIS hotel is about 400 m.
The Best Western can be reached by tram (line 1, direction "Winzerla", final station, 10 min walk) or bus (line 13 and at some times also 40 from downtown, stop "Winzergasse", 5 min walk). The bus lines 13 and 40 are connecting downtown, campus and Best Western.
By car:

Coming from the North (Berlin) or South (Munich) on the Autobahn A9, take the A4 on "Hermsdorfer Kreuz" towards Erfurt / Frankfurt M.. To reach the IBIS hotel, leave at exit "Jena-Lobeda", and drive to the city center. When you cross the Saale river and go below the railway tracks, you have to take a left turn in the Löbdergraben for the hotel IBIS.
To go to the Best Western or directly to the conference site, the IPHT at the "Beutenberg Campus", you have to leave at the exit Jena-Gschwitz and go towards city center. The Best Western is on the left hand site when the road climbs up a steep hill. Follow the signs "Beutenberg Campus" to the left. When you reach the campus, take the entrance at the left and follow the signs to the IPHT.