How to determine if the presenter will attend as a session chair As a session chair, it’s important to maintain schedule.

As shown in SPIE’s responsibilities of session chairs:


  If you find a presenter has failed to attend: 
  
  
  Note the no show on the Session Report form
  DO NOT move to the next paper.
  Attendees plan for the talks they want to hear based on the published schedule.
  Choose one of these options:
  […]
  


My question is how to determine if the presenter will attend? Maybe he will appear later.
I think you are misunderstanding the instructions.

Let's say a presenter is scheduled to begin their talk at 11:00.  If they are not there at 11:00, they have failed to attend, for the purposes of these instructions.  The instructions go on to say what you should do in that case.

It's not asking you to predict the future, or to guess at 11:00 whether they will show up at 11:15.  What happens at 11:15 is irrelevant.  If they weren't there at 11:00 they missed their talk.  Even if they show up later, it's too late.