en و موضوعات مربوط Other Related Subject پژوهشي Research <p>  <table cellspacing="0" cellpadding="0" width="100%"><tbody><tr><td><p>  inventory model, </p><p>  backorder </p><p>  buyer , </p><p>  vendor, </p><p>  lot for lot policy </p></td></tr></tbody></table><i>In this paper, an inventory model for two-stage supply chain is investigated. A supply chain with single vendor and single buyer is considered. We assume that shortage as a backorder is allowed for the buyer and the vendor makes the production set up every time the buyer places an order and supplies on a lot for lot basis. With these assumptions, the joint economic lot size model is introduced and the minimum joint total relevant cost and optimal order quantity and optimal shortage quantity are obtained for both the buyer and the vendor at the same time. Numerical </i><i /><i>example is given and then Sensitivity analysis is performed to study the effects of changes in the parameters on optimum joint total relevant cost and optimal order quantity and optimal shortage quantity </i><i>. </i></p> inventory model, backorder buyer ,vendor, lot for lot policy 127 134 http://ijiepr.iust.ac.ir/browse.php?a_code=A-10-277-3&slc_lang=en&sid=1 Mona Ahmadi Rad 180031947532846001012 180031947532846001012 No PhD student, Department of Industrial Engineering, K.N.Toosi University of Technology, Tehran, Iran Farid Khoshalhan khoshalhan@ kntu.ac.ir 180031947532846001013 180031947532846001013 Yes Assistant Professor, Department of Industrial Engineering, K.N.Toosi University of Technology, Tehran, Iran