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This is a special issue of the Iranian Journal of Operations Research that includes some of the
invited talks presented at the 11th international conference of the Iranian Operations Research Society
(IORS), organized jointly by IORS and Razi University of Kermanshah and held at the Razi
University, Kermanshah, Iran, May 2-4, 2018. The IORS conference is held annually and is the main
event for presentation of new theoretical and applied developments of OR. International participation
is enhanced by some invited talks presented by international scholars. There were over 400
participants, 170 accepted talks and 69 poster presentations. The selected papers for this special issue
were reviewed going through the usual reviewing process and 6 papers were accepted for publication.