P. Berman and C. Coulston. Speed is more powerful than clairvoyance. Nordic Journal of Computing, 6(2):181-193, 1999.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and or a fee. STOC 02, May 19 21, 2002, Montreal, Quebec, Canada. Copyright 2002 ACM 1 58113 495 9 02 0005 . 5.00. petitive analysis [6] and extra resource analysis [2, 5, 7, 13, 16, 17, 18, 20], to study several interesting problems related to the design of on line schedulers on di erent VOD systems and give provably e ective solutions for these problems. In a VOD system, a hot video is often requested over a short period of time (say, Friday 7 p.m. to 9 p.m. Due to the large number ....

....video comprises 120 time units. The total bandwidth for serving both clients is reduced from 240 to 121. ness, and Chan et al. 9] improved their result to obtain a 5 competitive scheduler. The second question is closely related to the extra resource analysis of on line algorithms (see, e.g. [2, 5, 7, 13, 16, 17, 18, 20]) As mentioned before, we have an on line scheduler which is 3 competitive for 20 skimming. Our result suggests that by taking advantage of extra resources, there is an online scheduler for 5 skimming which is 1.2375 competitive relative to 20 skimming. Furthermore, suppose we want to determine ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. Nordic J. Comp., 6(2):181-193, 1999.

.... cannot match or be competitive against the o ine adversary [2] In recent years, a plausible approach to achieving better performance guarantee for online scheduling (without restricting the inputs) is to allow the online scheduler to use a faster processor than the o ine adversary (e.g. [3, 5, 6, 9, 12,16, 18]) Intuitively, we use a faster processor to compensate the online scheduler for the lack of future information. The key question is whether a A preliminary version of this paper appeared in the Proceedings of the 14th ACM Annual Symposium on Parallel Algorithms and Architectures, 2002. ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255-263, 1998.

.... known algorithm achieves a competitive ratio of ( where k is the importance ratio [10] In recent years, a plausible approach to studying performance guarantee of on line algorithms (without making assumption on future inputs) is to allow on line schedulers to have faster processors (e.g. [4, 7, 9, 14, 8, 12, 13]) Speci cally, we would like to compare on line schedulers using a faster processor against o line schedulers using a normal speed processor. Intuitively, extra speed is needed to compensate an on line scheduler for the lack of future information. The key question is whether a moderate increase ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255-263, 1998.

.... the performance cannot match or be competitive against the o#ine adversary [2] In recent years, a plausible approach to studying better performance guarantee for online scheduling (without restricting the inputs) is to allow the online scheduler to use a faster processor than the o#ine adversary [3,5,7,10,14,16]. Intuitively, we need a faster processor to compensate the online scheduler for the lack of future information. The key question is whether a moderate amount of extra speed can # Department of Computer Science, University of Maryland, College Park, MD 20742, USA (cykoo cs.umd.edu) Department ....

....set of jobs passed to but not completed by Band 2 (i.e. I A1 A2 ) Furthermore, we need the following definition. Definition 2. The span of a job J is the period [r(J) d(J) and the span of a set of jobs is the union of the spans of all the jobs in S. e.g. the union of the spans [3, 6] and [5, 8] is [3, 8] Furthermore, let sp(S) be the total time included in the span of S. Theorem 9. p(A2 ) sp(I # ) Before proving Theorem 9, we note that Theorem 9 guarantees that EDF MSp is a four processor optimal algorithm for scheduling jobs with value densities in the range [1, ....

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P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proc. 6th SWAT, pages 255--263, 1998.

....algorithm. Notice that when k is large, such performance guarantee is not satisfactory. In recent years, a plausible approach to obtaining better performance guarantee without making assumption on future inputs is to allow the online scheduler to have more resources than the adversary (e.g. [4, 6, 8, 10, 14, 16]) Speci cally, we would like to compare the online scheduler using a faster processor or more than one (unit speed) processors against an adversary using a unit speed processor. Intuitively, the additional resources are needed to compensate the online scheduler for the lack of future information. ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255263, Stockholm, Sweden, 810 July 1998.

....o line algorithm. Indeed, in most settings, no online algorithm has this sort of performance guarantee [2, 8] In recent years, a plausible approach to studying performance guarantee for online scheduling without restricting the inputs is to allow the online scheduler to use faster processors [1, 3, 5, 9, 10, 13, 14]. Intuitively, we want to study how e ective faster processors can compensate the online scheduler for the lack of future information. Phillips et al. 14] were able to extend the optimality of edf to the underloaded, multiprocessor setting by allowing the online scheduler to use double speed ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255263, Stockholm, Sweden, 810 July 1998.

.... the performance cannot match or be competitive against the o ine adversary [2] In recent years, a plausible approach to studying better performance guarantee for online scheduling (without restricting the inputs) is to allow the online scheduler to use a faster processor than the o ine adversary [3, 5, 8, 11, 15, 17]. Intuitively, we use a faster processor to compensate the online scheduler for the lack of future information. The key question is whether a moderate amount of extra speed can lead to satisfactory competitiveness. Kalyanasundaram and Pruhs [11] are the rst to exploit a faster processor to derive ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255-263, 1998.

.... bound is tight as matching algorithms are also known [1, 9, 14] In recent years, there are a number of exciting results on improving performance guarantee without making assumption on future inputs; the basic idea is to allow the online scheduler to have more resources than the adversary (e.g. [3, 6 8, 10 12]) For the single processor deadline scheduling problem, the pioneer work of Kalyanasundaram and Pruhs [8] implies that the competitive ratio can be reduced arbitrarily if the on line scheduler is given a faster processor (e.g. the competitive ratio is roughly 2 if the processor speed increases ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255--263, Stockholm, Sweden, 8--10 July 1998.

.... ratio of ( where k is the importance ratio [9] In recent years, there are a number of exciting results on improving the performance guarantee without making assumption on future inputs; the basic idea is to allow the on line scheduler to have more resources than the adversary (e.g. [3, 6, 8, 13, 7, 11, 12]) For the single processor rm deadline scheduling problem, Kalyanasundaram and Pruhs [8] showed that the competitive ratio can be reduced signi cantly if the on line scheduler is given a faster processor. For instance, with a processor that is 32 times faster, the competitive ratio can be ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255-263, July 1998.

.... minimum value of # such that the cost of the on line algorithm is bounded by the cost of the optimal o line algorithm (i.e. the competitive ratio is at most 1) Resource augmentation was originally introduced by [12] and further widely studied for various scheduling and load balancing problems [5, 7, 12, 13, 15]. Note that if a sequence # contains at most # jobs, then ###(#) 0. By (1.1) any algorithm with nite competitive ratio needs to have zero cost and run all jobs on di erent machines in that case. All previous work assumed that the output needs to be collected by the same system, and hence the ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. Nordic Journal of Computing, 6:181-193, 1999. Also in Proc. 6th Biennial Scandinavian Workshop on Algorithm Theory, (SWAT'98) pp. 189-199.

....the non clairvoyant processor 2 by a factor of (1 ffl) times the offline processor. They use this resource augmentation technique to analyze a non clairvoyant algorithm for mean response time. They show that the competitive ratio of their algorithm is (1 1 ffl ) Berman and Coulston [2] improved the above results. They proved that with a v speed processor (v 2) the algorithm of Kalyanasundaram and Pruhs is 2=v competitive. 1.3 Our results We first consider the basic problem of scheduling jobs online without knowledge of the sizes of the jobs. We show that any deterministic ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. Nordic Journal of Computing, 6(2):181--193, 1999.

....a number of problems. It was already used in the paper where the competitive ratio was introduced [20] In that paper, the performance of some paging algorithms was studied, where they have more memory than the optimal o line algorithm. In several machine scheduling and load balancing problems [4, 8, 13, 14, 16, 18], the e ect of adding more or faster machines has been studied. We consider the following load balancing problem. Jobs arrive on line, where job j has a certain weight w j . The job has to be assigned immediately to a machine, adding w j to the machine s load. The on line algorithm has n ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Nordic Journal of Computing, pages 181-193, 1999.

....to a number of problems. It was already used in the paper where the competitive ratio was introduced [20] here the performance of some paging algorithms was studied, where the on line algorithm has more memory than the optimal o# line one. In several machine scheduling and load balancing problems [4, 8, 13, 14, 16, 18], the e#ect of adding more or faster machines has been studied. We consider the following load balancing problem. Jobs arrive on line, where job j has a certain weight w j . The job has to be assigned immediately to a machine, adding w j to the machine s load. The on line algorithm has n identical ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Scandinavian Workshop on Algorithms and Theory, pages 255--263, 1998.

....adversary. It is indeed known that in many settings of deadline scheduling, no online algorithm has this sort of performance guarantee [1, 5] In recent years, a plausible approach to studying performance guarantee is to allow the online scheduler to use faster processors than the o line adversary [2, 6, 7, 10, 12]. Intuitively, using faster processors compensate the online scheduler for the lack of future information In particular, for deadline scheduling on multiprocessors, Phillips et al. 12] were able to show that EDF using speed 2 processors is optimal for hard deadline systems. This means that if the ....

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proc. 6th SWAT, pages 255263, 1998.

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P. Berman and C. Coulston. Speed is more powerful than clairvoyance. Nordic Journal of Computing, 6(2):181-193, 1999.

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Piotr Berman and Chris Coulston. Speed is more powerful than clairvoyance. Nordic Journal of Computing, pages 181-193, 1999.

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Piotr Berman and Chris Coulston. Speed is more powerful than clairvoyance. In Proceedings of the 6th Scandinavian Workshop on Algorithm Theory, pages 255-263, 1998.

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Piotr Berman and Chris Coulston. Speed is more powerful than clairvoyance. Nordic Journal of Computing, pages 181-193, 1999.

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P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255-263, 1998.

No context found.

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proceedings of the Sixth Scandinavian Workshop on Algorithm Theory, pages 255--263, Stockholm, Sweden, July 1998.

No context found.

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proc. 6th SWAT, pages 255--263, 1998.

No context found.

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. In Proc. 6th SWAT, pages 255--263, 1998.

No context found.

P. Berman and C. Coulston. Speed is more powerful than clairvoyance. Nordic Journal of Computing, 6(2):181--193, 1999.

No context found.

P. Berman and C. Coulston, "Speed is more powerful than clairvoyance", Scandinavian Workshop on Algorithms and Theory, 255-263, 1998.

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P. Berman and C. Coulston. Speed is more powerful than clairvoyance. Nordic Journal of Computing, 6:181--193, 1999.

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