If you really want a single word, I would suggest a heading of either Lectures or perhaps Presentations. If you're okay with more than one word, I would combine them as Lectures and Presentations.
From the Oxford Living Dictionaries:
An educational talk to an audience, especially one of students in a university.
‘in each course there are supporting lectures and tutorials’
A speech or talk in which a new product, idea, or piece of work is shown and explained to an audience.
‘a sales presentation’
You could also use Lectures and Posters, if that would be understood to be referring to the posters used in poster sessions (which, I'll admit, I had to look up).
I'm not sure there's a single word that would cover both Lectures/Talks and Posters, other than, perhaps, presentations.