ISE Welcomes Ahmed Saif on 11/18/16

Cold Supply Chain Design with Environmental Considerations: A Simulation-Optimization Approach

Seminar by Ahmed Saif, Postdoc

HEC Montréal

Friday, November 18th, 11:30 am – 12:30 pm

210E Baker Systems, 1971 Neil Avenue

In response to strict regulations and increased environmental awareness, firms are striving to reduce the global warming impact of their operations. Cold supply chains have high levels of greenhouse gas emissions due to the high energy consumption and refrigerant gas leakages. We model the cold supply chain design problem as a mixed-integer concave minimization problem with dual objectives of minimizing the total cost and the global warming impact. Demand is modeled as a general distribution, whereas inventory is managed using a known policy but without explicit formulas for the inventory cost and maximum level functions. We propose a novel hybrid simulation-optimization approach to solve the problem. Lagrangian decomposition is used to compose the model into an integer programming subproblem and sets of single variable concave minimization subproblems that are solved using simulation-optimization. We provide closed-form expressions for the Lagrangian multipliers so that the Lagrangian bound is obtained in a single iteration, alongside a feasible solution. The approach is verified through testing on two realistic cases from different industries, and managerial insights are drawn.

Ahmed Saif is a postdoctoral fellow in the department of Decision Sciences at HEC Montreal. He completed his Ph.D. in Management Sciences from the University of Waterloo in January 2016. He also holds a master’s degree in Engineering Systems & Management and an MBA. Ahmed’s research interests lie in the area of optimization under uncertainty and data analytics. His current research focuses on data-driven robust optimization approaches and their applications in supply chains, particularly integrated, multistage supply chain network design problems. He worked also on warehouse logistics and developed performance improvement approaches that combine data analytics and optimization tools and that utilize the sheer amount of order processing data collected by warehouses. Furthermore, he conducted research in global optimization, healthcare logistics, airline crew scheduling and hybrid power systems. Ahmed has a diverse teaching experience in North American and International postsecondary institutions. Moreover, he worked in engineering and business consulting for about 4 years and had multiple industry internships while pursuing graduate degrees. Ahmed’s research attracted funding from federal and provincial agencies and from the industry.