This type of conference session is longer (often 90 minutes) and entails 5 or more presenters who are proposing papers on the same topic or theme. 
All presenters will speak individually (15 minutes approximately) and there will be additional time for discussion and questions.  These sessions have a more narrow focus and therefore attract attendees with a genuine interest in the topic. However, while the audience is well-educated, they are usually not specialists or experts on the topic.