Semi-online scheduling on two uniform processors

Enrico Angelelli, Maria Grazia Speranza, Z. Tuza

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

In this paper we consider the problem of semi-online scheduling on two uniform processors, in the case where the total sum of the tasks is known in advance. Tasks arrive one at a time and have to be assigned to one of the two processors before the next one arrives. The assignment cannot be changed later. The objective is the minimization of the makespan. Assume that the speed of the fast processor is s, while the speed of the slow one is normalized to 1. As a function of s, we derive general lower bounds on the competitive ratio achievable with respect to offline optimum, and design on-line algorithms with guaranteed upper bound on their competitive ratio. The algorithms presented for s ≥ sqrt(3) are optimal, as well as for s = 1 and for frac(1 + sqrt(17), 4) ≤ s ≤ frac(1 + sqrt(3), 2).

Original languageEnglish
Pages (from-to)211-219
Number of pages9
JournalTheoretical Computer Science
Volume393
Issue number1-3
DOIs
Publication statusPublished - Mar 20 2008

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Online Scheduling
Competitive Ratio
Scheduling
Assignment
Lower bound
Upper bound
Design

Keywords

  • Competitive analysis
  • Semi-online scheduling
  • Uniform processors

ASJC Scopus subject areas

  • Computational Theory and Mathematics

Cite this

Semi-online scheduling on two uniform processors. / Angelelli, Enrico; Speranza, Maria Grazia; Tuza, Z.

In: Theoretical Computer Science, Vol. 393, No. 1-3, 20.03.2008, p. 211-219.

Research output: Contribution to journalArticle

Angelelli, Enrico ; Speranza, Maria Grazia ; Tuza, Z. / Semi-online scheduling on two uniform processors. In: Theoretical Computer Science. 2008 ; Vol. 393, No. 1-3. pp. 211-219.
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