Bielefeld is connected to the German high-speed rail network: Train connections can be checked here. The closest airports are Hannover (110 km), Düsseldorf (190 km), Köln-Bonn (200 km), Frankfurt (320 km).
Once in Bielefeld, you can reach the conference venue either by taxi (~10€ from the main station) or by metro (station: Universität) plus a short walk.