An evaluation of scheduling heuristics for non-identical
parallel processors was performed. There has been
limited research that has focused on scheduling of parallel
processors. This research generalizes the results from
prior work in this area and examines complex scheduling
rules in terms of flow time, tardiness, and proportion of
tardy jobs. Several factors affecting the system were
examined and scheduling heuristics were developed. These
heuristics combine job allocation and job sequencing
functions. A number of system features were considered in
developing these heuristics, including setup times and
processor utilization spread. The heuristics used different
sequencing rules for job sequencing including random,
Shortest Process Time (SPT), Earlier Due Date (EDD), and
Smaller Slack (SS).
A simulation model was developed and executed to study
the system. The results of the study show that the effect
of the number of machines, the number of products, system
loading, and setup times were significant for all
performance measures. The effect of number of machines was
also found to be significant on flow time and tardiness.
Several two-factor interactions were identified as
significant for flow time and tardiness.
The SPT-based heuristic resulted in minimum job flow
times. For tardiness and proportion of tardy jobs, the EDD-based
heuristic gave the best results. Based on these
conclusions, a "Hybrid" heuristic that combined SPT and EDD
considerations was developed to provide tradeoff between
flow time and due date based measures. / Graduation date: 1995
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/35188 |
| Date | 29 September 1994 |
| Creators | Kuo, Chun-Ho |
| Contributors | Randhawa, Sabah |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
Page generated in 0.0021 seconds