What affiliation should I use for a paper that I partly wrote in a previous institution? I am writing a research paper to be submitted to an IEEE conference. Part of the work was performed as a part of my University. I have graduated from there and am no longer a part of the university. My work has evolved and I would like to publish these results. What should my affiliation be for this paper? Should I use my old university as my affiliation or using something like IEEE-RAS member is fine?
To the best of my knowledge, you would need to somehow indicate both but a similar question has been asked and answered before: 

What affiliation to put on an academic paper for alumni authors? 

You have to acknowledge that part of the work was performed when you were at your university. I had a similar situation where I did part of the work when I was at university as part of my PhD and then completed the work when I took up a position at a research institution. For the paper, I was listed as having two affiliations.