Supply Chain Scheduling: Assembly Systems
Speaker: Nicholas G. Hall, The Ohio State University
Coauthor: Zhi-Long Chen, University of Maryland
We study conflict and
cooperation issues in supply chain manufacturing. Consider an assembly
system where suppliers provide parts to a manufacturer. A product cannot
be delivered until all its parts have been supplied. The manufacturer performs
nonbottleneck operations, for example outsourced assembly, packaging and
delivery, for each product. Two classical scheduling objectives are considered:
minimization of the total completion time (i.e., work-in-process) and of
the maximum lateness (i.e., customer satisfaction). We analyze how far
from optimal the best schedule for a suppliers' scheduling problem can
be for the corresponding manufacturer's problem, and vice versa. To resolve
these conflicts, we consider four alternative assumptions about the relative
bargaining power of the suppliers and the manufacturer, and in each case
describe a practical mechanism for cooperation between the decision makers.
Specifying the optimal strategies implied by these mechanisms requires
the solution of various scheduling problems by the suppliers, the manufacturer
and the overall system. For all these scheduling problems, we provide either
an efficient algorithm or a proof of intractability. Moreover, for two
problems that we show are intractable, we describe heuristics and analyze
their worst case performance or demonstrate asymptotic optimality of their
solutions. We demonstrate computationally that the cost saving which cooperation
between the decision makers provides is significant in many cases. Extensions
of our models to consider bottleneck operations at the manufacturer and
transportation times are also developed. Several future research directions
will also be discussed. This work is part of a larger study of operational
decision making in deterministic supply chain environments. The format
of the talk is a Powerpoint presentation with minimal use of notation.
A general knowledge of operations research, without necessarily a detailed
knowledge of scheduling theory, is a sufficient background for understanding
the talk.