Results 1  10
of
38
Online Scheduling Revisited
, 2000
"... We present a new online algorithm, MR, for nonpreemptive scheduling of jobs with known processing times on m identical machines which beats the best previous algorithm for m 64. For m ! 1 its competitive ratio approaches 1 + q 1+ln2 2 ! 1:9201. ..."
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Cited by 41 (0 self)
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We present a new online algorithm, MR, for nonpreemptive scheduling of jobs with known processing times on m identical machines which beats the best previous algorithm for m 64. For m ! 1 its competitive ratio approaches 1 + q 1+ln2 2 ! 1:9201.
Dynamic TCP acknowledgement and other stories about e/(e  1)
 ALGORITHMICA
, 2001
"... We present the first optimal randomized online algorithms for the TCP acknowledgment problem [5] and the Bahncard problem [8]. These problems are wellknown to be generalizations of the classical online ski rental problem, however, they appeared to be harder. In this paper, we demonstrate that a nu ..."
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Cited by 40 (1 self)
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We present the first optimal randomized online algorithms for the TCP acknowledgment problem [5] and the Bahncard problem [8]. These problems are wellknown to be generalizations of the classical online ski rental problem, however, they appeared to be harder. In this paper, we demonstrate that a number of online algorithms which have optimal competitive ratios of e/(e  1), including these, are fundamentally no more complex than ski rental. Our results also suggest a clear paradigm for solving ski rentallike problems.
Online scheduling
 ONLINE ALGORITHMS, LECTURE NOTES IN COMPUTER SCIENCE 1442
, 1998
"... ..."
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OnLine Scheduling  A Survey
, 1997
"... Scheduling has been studied extensively in many varieties and from many viewpoints. Inspired by applications in practical computer systems, it developed into a theoretical area with many interesting results, both positive and negative. The basic situation we study is the following. We have some sequ ..."
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Cited by 38 (0 self)
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Scheduling has been studied extensively in many varieties and from many viewpoints. Inspired by applications in practical computer systems, it developed into a theoretical area with many interesting results, both positive and negative. The basic situation we study is the following. We have some sequence of jobs that have to be processed on the machines available to us. In the most basic problem, each job is characterized by its running time and has to be scheduled for that time on one of the machines. In other variants there may be additional restrictions or relaxations specifying which schedules are allowed. We want to schedule the jobs as efficiently as possible, which most often means that the total length of the schedule (the makespan) should be as small as possible, but other objective functions are also considered. The notion of an online algorithm is intended to formalize the realistic scenario, where the algorithm does not have the access to the whole inp...
Online Load Balancing for Related Machines
, 1997
"... this paper appeared in Proceedings of WADS 97, LNCS 1272, SpringerVerlag, 1997, 116125. ..."
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Cited by 33 (1 self)
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this paper appeared in Proceedings of WADS 97, LNCS 1272, SpringerVerlag, 1997, 116125.
Preemptive Multiprocessor Scheduling with Rejection
 Theoretical Computer Science
, 1999
"... The problem of online multiprocessor scheduling with rejection was introduced by Bartal, Leonardi, MarchettiSpaccamela, Sgall and Stougie [4]. They show that for this problem the competitive ratio is 1+ OE ß 2:61803, where OE is the golden ratio. A modified model of multiprocessor scheduling with r ..."
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Cited by 27 (3 self)
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The problem of online multiprocessor scheduling with rejection was introduced by Bartal, Leonardi, MarchettiSpaccamela, Sgall and Stougie [4]. They show that for this problem the competitive ratio is 1+ OE ß 2:61803, where OE is the golden ratio. A modified model of multiprocessor scheduling with rejection is presented where preemption is allowed. For this model, it is shown that better performance is possible. An online algorithm which is (4+ p 10)=3 ! 2:38743competitive is presented. We prove that the competitive ratio of any online algorithm is at least 2.12457. We say that an algorithm schedules obliviously if the accepted jobs are scheduled without knowledge of the rejection penalties. We also show a lower bound of 2.33246 on the competitive ratio of any online algorithm which schedules obliviously. As a subroutine in our algorithm, we use a new optimal online algorithm for preemptive scheduling without rejection. This algorithm never acheives a larger makespan than that of the...
SemiOnline Scheduling With Decreasing Job Sizes
, 1998
"... We investigate the problem of semionline 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 semionline scheduling with decreasing job sizes. We give matching lower and upper bounds on the ..."
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Cited by 27 (2 self)
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We investigate the problem of semionline 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 semionline 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 2 (1+ p 3) ß 1:36603, as the number of machines goes to infinity. Our results are also best possible for randomized algorithms. For the nonpreemptive variant of semionline scheduling with decreasing job sizes, a result of Graham [SIAM J. Appl. Math. 17(1969), 263269] yields a ( 4 3 \Gamma 1 3m ) competitive deterministic nonpreemptive algorithm. For m = 2 machines, we prove that this algorithm is best possible (it is 7 6 competitive). For m = 3 machines we give a lower bound of (1 + p 37)=6 ß 1:18046. Finally, we present a randomized nonpreemptive 8 7 competitive algorithm for m = 2 machines and pro...
Online scheduling with bounded migration.
 Mathematics of Operations Research,
, 2009
"... Consider the classical online scheduling problem where jobs that arrive one by one are assigned to identical parallel machines with the objective of minimizing the makespan. We generalize this problem by allowing the current assignment to be changed whenever a new job arrives, subject to the constr ..."
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Cited by 24 (1 self)
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Consider the classical online scheduling problem where jobs that arrive one by one are assigned to identical parallel machines with the objective of minimizing the makespan. We generalize this problem by allowing the current assignment to be changed whenever a new job arrives, subject to the constraint that the total size of moved jobs is bounded by β times the size of the arriving job. For small values of β, we obtain several simple online algorithms with constant competitive ratio. We also present a linear time 'online approximation scheme', that is, a family of online algorithms with competitive ratio 1 + and constant migration factor β( ), for any fixed > 0.
A Lower Bound for OnLine Scheduling on Uniformly Related Machines
, 1999
"... We consider the problem of online scheduling of jobs arriving one by one on uniformly related machines, with or without preemption. We prove a lower bound of 2, both with and without preemption, for randomized algorithms working for an arbitrary number of machines. For a constant number of machines ..."
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Cited by 23 (11 self)
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We consider the problem of online scheduling of jobs arriving one by one on uniformly related machines, with or without preemption. We prove a lower bound of 2, both with and without preemption, for randomized algorithms working for an arbitrary number of machines. For a constant number of machines we give new lower bounds for the preemptive case.
Optimal Preemptive SemiOnline Scheduling to Minimize Makespan on Two Related Machines
 Operations Research Letters
, 2002
"... We study a preemptive semionline scheduling problem. Jobs with nonincreasing sizes arrive one by one to be scheduled on two uniformly related machines. We analyze the algorithms as a function of the speed ratio (q 1) between the two machines. We design algorithms of optimal competitive ratio ..."
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Cited by 15 (2 self)
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We study a preemptive semionline scheduling problem. Jobs with nonincreasing sizes arrive one by one to be scheduled on two uniformly related machines. We analyze the algorithms as a function of the speed ratio (q 1) between the two machines. We design algorithms of optimal competitive ratio for all values of q, and show that for q > 2, idle time needs to be introduced. This is the rst preemptive scheduling problem over list, where idle time is provably required.