The meeting will start in the morning of Wednesday, September the 6th, and will end in the afternoon / early evening of Friday, September the 8th.
The most convenient way is to take a taxi at the airport. You can get a taxi just outside both the international and domestic arrival halls. There are both regular taxis and the yellow airport taxis. With the latter you can usually share the costs with other passengers going the same way. The taxi operators have service desks in International arrivals hall 2. Taking a regular taxi to Otaniemi costs about 30 euros and takes about 20 minutes.
There is no direct bus connection to Otaniemi. You can, however, take bus 540 or 514 from the airport and change to 52, 510, 512 or 550 in Leppävaara to get to Otaniemi. There is a short walk from the bus stop to the hotel, bus 550 comes closest. The YTV journey planner provides you with timetables and detailed maps. If you are going to Helsinki city centre from the airport, bus 615 is the easiest option. The bus fare is 3,60 euros (if you plan to travel more by bus, check also the other ticket types, especially the tourist tickets). Tickets can be bought from the driver.
The Otaniemi campus is easy to get around as everything is within a
walking distance. The Dipoli conference center is just a few hundred
metres from the hotel. There is also a grocery shop, a pharmacy and a
post office near Dipoli (where the white cross is on the map). To go to
Helsinki city centre, you can take a bus from Otaniementie (bus stop Dipoli). Buses 102 and 103 are the fastest,
194 and 195 a bit slower. Avoid buses 505 and 506, as they do not go to
the city centre.