Lot-sizing scheduling techniques determine what amount is
required to meet forecasted demand whilst minimising the
sum of setup and holding costs. These techniques are not
adequate to provide an optimal solution to bottleneck
facility problems which do not meet demands placed on
them. Thus, it is necessary to analyse how much should be
produced from each product with bottleneck facilities.
Therefore a lot-sizing problem with bottleneck(s) under
rolling schedule environment is the subject of this
thesis.
This research proposes a simple heuristic for multi-level
lot-sizing problems where there is a bottleneck. Previous
methods to solve this problem have formulated the problem
as an integer programming problem and solved the problem
using a Lagrangian relaxation embedded within the branch
and bound procedure. Then the proposed heuristic is
extended for multiple bottleneck problems, and finally
applied to the real life problem.
In this research it is suggested that items to be
produced can be grouped into two types and a simple but
efficient heuristic can be used to determine the
production quantities required. A program was developed
to compute production levels and was found to require
only a small fraction of the computer time required by
the full integer programming approach and to produce
solutions of reasonable quality. The heuristic is simple
to implement.
Keywords: heuristics, inventory, lot-sizing, scheduling,
production, bottleneck, linear programming, integer
programming.