Nothing Special   »   [go: up one dir, main page]

skip to main content
article

Semi-online scheduling with decreasing job sizes

Published: 01 December 2000 Publication History

Abstract

We investigate the problem of semi-online scheduling jobs on m identical parallel machines where the jobs arrive in order of decreasing sizes. We present a complete solution for the preemptive variant of semi-online scheduling with decreasing job sizes. We give matching lower and upper bounds on the competitive ratio for any fixed number m of machines; these bounds tend to (1+3)/2~1.36603, as the number of machines goes to infinity. Our results are also the best possible for randomized algorithms. For the non-preemptive variant of semi-online scheduling with decreasing job sizes, a result of Graham (SIAM J. Appl. Math. 17 (1969) 263-269) yields a (4/3-1/(3m))-competitive deterministic non-preemptive algorithm. For m=2 machines, we prove that this algorithm is the best possible (it is 7/6-competitive). For m=3 machines we give a lower bound of (1+37)/6~1.18046. Finally, we present a randomized non-preemptive 8/7-competitive algorithm for m=2 machines and prove that this is optimal.

References

[1]
S. Albers, Better bounds for online scheduling, Proceedings of the 29th ACM Symposium on Theory of Computing, 1997, pp. 130-139.
[2]
Y. Azar, O. Regev, Online bin stretching, Proceedings of RANDOM, 1998, pp. 71-82.
[3]
Bartal, Y., Fiat, A., Karloff, H. and Vohra, R., New algorithms for an ancient scheduling problem. J. Comput. System Sci. v51. 359-366.
[4]
Bartal, Y., Karloff, H. and Rabani, Y., A better lower bound for on-line scheduling. Inform. Process. Lett. v50. 113-116.
[5]
Chen, B., van Vliet, A. and Woeginger, G., A lower bound for randomized on-line scheduling algorithms. Inform. Process. Lett. v51. 219-222.
[6]
Chen, B., van Vliet, A. and Woeginger, G., New lower and upper bounds for on-line scheduling. Oper. Res. Lett. v16. 221-230.
[7]
Chen, B., van Vliet, A. and Woeginger, G., An optimal algorithm for preemptive on-line scheduling. Oper. Res. Lett. v18. 127-131.
[8]
Faigle, U., Kern, W. and Turín, G., On the performance of on-line algorithms for partition problems. Acta Cybernet. v9. 107-119.
[9]
Galambos, G. and Woeginger, G., An online scheduling heuristic with better worst case ratio than Graham's list scheduling. SIAM J. Comput. v22. 349-355.
[10]
Graham, R.L., Bounds for certain multiprocessing anomalies. Bell Systems Tech. J. v45. 1563-1581.
[11]
Graham, R.L., Bounds on multiprocessing timing anomalies. SIAM J. Appl. Math. v17. 263-269.
[12]
Karger, D., Phillips, S. and Torng, E., A better algorithm for an ancient scheduling problem. J. Algorithms. v20. 400-430.
[13]
Kellerer, H., Kotov, V., Speranza, M. and Tuza, Z., Semi online algorithms for the partition problem. Oper. Res. Lett. v21. 235-242.
[14]
Ordinal algorithms for parallel machine scheduling. Oper. Res. Lett. v18. 223-232.
[15]
Reingold, N., Westbrook, J. and Sleator, D., Randomized competitive algorithms for the list update problem. Algorithmica. v11. 15-32.
[16]
S.S Seiden, Randomized algorithms for that ancient scheduling problem, Proceedings of the Fifth Workshop on Algorithms and Data Structures, 1997, pp. 210-223.
[17]
S.S. Seiden, Randomized online multiprocessor scheduling, Algorithmica, to appear.
[18]
J. Sgall, On-line scheduling on parallel machines, Ph.D. thesis, Carnegie-Mellon University, 1994
[19]
Sgall, J., A lower bound for randomized on-line multiprocessor scheduling. Inform. Process. Lett. v63. 51-55.

Cited By

View all

Recommendations

Comments

Please enable JavaScript to view thecomments powered by Disqus.

Information & Contributors

Information

Published In

cover image Operations Research Letters
Operations Research Letters  Volume 27, Issue 5
December, 2000
47 pages

Publisher

Elsevier Science Publishers B. V.

Netherlands

Publication History

Published: 01 December 2000

Author Tags

  1. Analysis of algorithms
  2. Competitive ratio
  3. Online algorithms
  4. Scheduling

Qualifiers

  • Article

Contributors

Other Metrics

Bibliometrics & Citations

Bibliometrics

Article Metrics

  • Downloads (Last 12 months)0
  • Downloads (Last 6 weeks)0
Reflects downloads up to 28 Nov 2024

Other Metrics

Citations

Cited By

View all

View Options

View options

Login options

Media

Figures

Other

Tables

Share

Share

Share this Publication link

Share on social media