Gopal Easwaran,
ISEN Ph.D. Candidate
Contact: Email - Webpage

Advisor:
Dr. Sila Cetinkaya
Contact: Email - Webpage

Dr. Halit Uster
Contact: Email - Webpage

Location : @Zach 340 (2.15-3.45 pm)

"Application of Benders for a Multi-Product Closed-Loop Supply Chain Network Design Model"
Short Bio:
Gopal Easwaran is a doctoral student in the Industrial and Systems Engineering Department at Texas A&M University. He is working with his Co-chairs Dr. Sila Cetinkaya and Dr. Halit Uster towards his dissertation. He received his B.E. in Mechanical Engineering from PSG College of Technology, India and his M.S. degree in Industrial Engineering from Texas A&M University in 2000 and 2003, respectively. In 2003, he enrolled in the doctoral program and he is a Graduate Research Assistant in the Logistics and Networked Systems Research Lab. His research interests are logistics, supply chain management, and applied optimization. He is a student member of the INFORMS, and IIE.

Seminar Abstract:
In recent years, due to economical, environmental and legislative requirements, a number of firms are adopting to product recovery practices. Remanufacturing is one such product recovery practice that involves collection and sorting of used products for reclamation of previously added value to produce a product that is identical in quality to the original product. Remanufacturing extends the scope of traditional logistics to include not only forward flow of products from the manufacturers to the customers, but also reverse flow of used or end-of-life products from the customers to the manufacturers. Adoption of remanufacturing strategies requires a transformation of existing traditional unidirectional supply chains to a closed-loop supply chain (CLSC) systems. We consider a multi-product closed-loop supply chain network design problem where we locate the collection centers and remanufacturing facilities and as well determine the material flow in the whole network so as to minimize the fixed location, variable processing and transportation costs. We provide an effective problem formulation that is amenable to efficient Benders reformulation and exact solution approach. We present dual solution approaches to generate strong Benders cuts and as well as three additional approaches to adding Benders cuts in addition to classical single Benders cut approach. These cuts are obtained via dual problem disaggregation based on forward and reverse flows, based on products and both. We observe that the disaggregation and, thus, the use of multiple cuts in the master problem, generate stronger lower bounds and promote faster convergence.

Homarjun Agrahari,
ISEN Ph.D. Candidate
Contact: Email - Webpage

Advisor:

Dr. Halit Uster
Contact: Email - Webpage

Location : @Zach 203 (5:30 - 6:30 pm)

"Multi-Commodity Flow Distribution Network Design With Intermediate Truckload Consolidation"
Short Bio:
Homarjun Agrahari received bachelor's degree in mechanical engineering and master's degree in Computer Integrated Manufacturing in 2001, both from Indian Institute of Technology, Bombay. After completion of his studies, he worked in the industry as Technology Consultant. He joined the PhD program at Texas A&M University in the fall of 2003. Homarjun is currently working with Dr. Halit Uster in the Logistics and Networked Systems Research Laboratory. His research interests include mathematical programming, discrete optimization and supply chain design.

Seminar Abstract:
A multi-commodity network design problem where the consolidation of smaller loads (commodities) into truckloads is explicitly modeled in a compact mathematical formulation. The setting and the model address common practice in small package and mail delivery operations. In the talk, mathematical formulation followed by an efficient compound neighborhood search method and three metaheuristic algorithms will be discussed. Computational results will also be illustrated for the relative efficiency and effectiveness of the compound neighborhood functions and metaheuristic algorithms.