The papers from each conference have been collected into a set of PDF (and physical) books. These are quite expensive to download, but working at a university means I have free access to them at the moment.
Topics include things unrelated to IF such as animation and virtual interfaces, but there are many subjects related to IF: narrative theory, story generation, agency, player emotions, drama management, autonomous characters, emergent narrative and natural language.
I haven’t been to an ICIDS conference, but you can read a first hand account from Juhana Leinonen who attended in 2015 and Emily Short who was invited to talk about Versu in 2014.
Here are the papers I’ve come across that are relevant to this blog, along with links where I could find them.