It depends. If you need to submit a paper to the conference and get it reviewed and accepted, the answer is definitely no. However, you may be invited to speak at the conference on a particular topic, and you may present an entire research stream which would include already published papers (i.e., your talk would be based on a number of papers you previously published).
It depends. If you need to submit a paper to the conference and get it reviewed and accepted, the answer is definitely no. However, you may be invited to speak at the conference on a particular topic, and you may present an entire research stream which would include already published papers (i.e., your talk would be based on a number of papers you previously published).
You may present a different version of the paper. But usually scholars tend to present papers at their early stage to get feedback, finalize the work, and then submit the final version to a journal.