3 research outputs found
Single Item Lot Sizing Problem for a Warm/Cold Process with Immediate Lost Sales
Cataloged from PDF version of article.We consider the dynamic lot-sizing problem with finite capacity and possible lost sales for a process that could be kept
warm at a unit variable cost for the next period t + 1 only if more than a threshold value Qt has been produced and would
be cold, otherwise. Production with a cold process incurs a fixed positive setup cost, Kt and setup time, St, which may be
positive. Setup costs and times for a warm process are negligible. We develop a dynamic programming formulation of the
problem, establish theoretical results on the structure of the optimal production plan in the presence of zero and positive
setup times with Wagner–Whitin-type cost structures. We also show that the solution to the dynamic lot-sizing problem
with lost sales are generated from the full commitment production series improved via lost sales decisions in the presence of
a warm/cold process.
2006 Elsevier B.V. All rights reserved
Dynamic lot sizing for a warm/cold process: Heuristics and insights
Cataloged from PDF version of article.We consider the dynamic lot sizing problem for a warm/cold process where the process can be kept
warm at a unit variable cost for the next period if more than a prespecified quantity has been produced.
Exploiting the optimal production plan structures, we develop nine rule-based forward solution
heuristics. Proposed heuristics are modified counterparts of the heuristics developed previously for
the classical dynamic lot sizing problem. In a numerical study, we investigate the performance of the
proposed heuristics and identify operating environment characteristics where each particular heuristic
is the best or among the best. Moreover, for a warm/cold process setting, our numerical studies indicate
that, when used on a rolling horizon basis, a heuristic may also perform better costwise than a solution
obtained using a dynamic programming approach.
& 2012 Elsevier B.V. All rights reserved