2nd February 2011, 6:00pm
Production Lot Sizing and Scheduling with Non-Triangular Sequence-Dependent Setup Times, Dr Alistair Clark (AWE)
Joint IMA/OR Society event
Abstract
This presentation considers a production lot sizing and scheduling problem with sequencedependent setup times that are not triangular. Consider, for example, a product p that contaminates another product r unless either a decontamination occurs as part of a substantial setup time st(pr) or there is a product q that absorb p’s contamination. When setup times are “triangular” then st(pr)<= st(pq) + st(qr) and there is always an optimal lot sequence with at most one lot per product per period (AM1L). However, product q’s ability to absorb p’s contaminants could result in shorter non-triangular setup times such that st(pr) > st(pq) + st(qr). The implication is that it can be sometimes be optimal for q to be produced in more than one lot within the same period, breaking the 1LPPPP assumption in most research. This presentation formulates and explains a new optimal model that not only permits multiple lots per product per period (ML), but also prohibits sequence subtours using a polynomial number of constraints. Initial computational tests demonstrate its effectiveness compared to the equivalent AM1L model.
Venue: Room 2Q48, Q block, Frenchay Campus, UWE, Coldharbour Lane, Bristol
No charge is made to attend meetings and non-members are welcome.
