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Scheduling to Minimize Average Completion Time: Off-Line and On-Line Approximation Algorithms

Leslie A. Hall, Andreas S. Schulz, David B. Shmoys, Joel Wein
1997 Mathematics of Operations Research  
Our second approach yields on-line algorithms for these problems: in this setting, we are scheduling jobs that continually arrive to be processed and, for each time t, we must construct the schedule until  ...  completion times.  ...  Acknowledgments We are grateful to Cor Hurkens, Cindy Phillips, Maurice Queyranne, Aravind Srinivasan, Cli Stein, and Marjan Van den Akker for helpful discussions and to the anonymous referees for their  ... 
doi:10.1287/moor.22.3.513 fatcat:hleo6mnrrjb7pazluani7pxdsm

Scheduling to Minimize Average Completion Time Revisited: Deterministic On-line Algorithms

Nicole Megow, Andreas S. Schulz
2003 Social Science Research Network  
We consider the scheduling problem of minimizing the average weighted completion time on identical parallel machines when jobs are arriving over time.  ...  on-line algorithms, which are (4 + ε)-competitive in either case.  ...  We consider the problem of scheduling jobs arriving over time on-line on identical parallel machines to minimize the sum of weighted completion times.  ... 
doi:10.2139/ssrn.460981 fatcat:fs74k2hdg5b73nfary3pmp7yji

Scheduling to Minimize Average Completion Time Revisited: Deterministic On-Line Algorithms [chapter]

Nicole Megow, Andreas S. Schulz
2004 Lecture Notes in Computer Science  
We consider the scheduling problem of minimizing the average weighted completion time on identical parallel machines when jobs are arriving over time.  ...  on-line algorithms, which are (4 + ε)-competitive in either case.  ...  We consider the problem of scheduling jobs arriving over time on-line on identical parallel machines to minimize the sum of weighted completion times.  ... 
doi:10.1007/978-3-540-24592-6_18 fatcat:hhlegkizpfbslj6jyu5zdri23y

Off-line and on-line guaranteed start-up delay for Media-on-Demand with stream merging

Amotz Bar-Noy, Justin Goshi, Richard E. Ladner
2006 Journal of Discrete Algorithms  
We describe an on-line delay guaranteed algorithm that operates without knowledge of the time horizon size, and show that it performs asymptotically close to the optimal off-line algorithm.  ...  We construct an efficient O(n) optimal off-line algorithm for a time horizon that is composed of n time slots, where the length of one slot is the guaranteed start-up delay.  ...  We showed both analytically and empirically that the on-line algorithm performs close to the optimal off-line algorithm as the time horizon goes to infinity.  ... 
doi:10.1016/j.jda.2005.01.007 fatcat:lowhk6kpdjdilexegcenukczuu

Optimal Time-Critical Scheduling via Resource Augmentation

Phillips, Stein, Torng, Wein
2002 Algorithmica  
When viewed from the perspective of traditional worst-case analysis, no good on-line algorithms exist for these problems, and for some variants no good off-line algorithms exist unless P = "P.  ...  We study these problems using a relaxed notion of competitive analysis, introduced by Kalyanasundaram and Pruhs, in which the on-line algorithm is allowed more resources than the optimal off-line algorithm  ...  off-line algorithms for the minimization of average flow time with performance guarantees of good quality for any NP-hard variant of the problem.  ... 
doi:10.1007/s00453-001-0068-9 fatcat:ac35hr6ezvcctaaeo5yud35x64

Scheduling jobs that arrive over time [chapter]

Cynthia Phillips, Clifford Stein, Joel Wein
1995 Lecture Notes in Computer Science  
Many of the algorithms generalize to the minimization of average weighted completion time as well. ' P  ...  A natural and basic problem in scheduling theory is to provide good average quality of service to a stream of jobs that arrive over time.  ...  We distinguish between off-Zine and on-line algorithms.  ... 
doi:10.1007/3-540-60220-8_53 fatcat:bwfb6ysqdjgunkvf7v3eaolzey

Optimal on-line flow time with resource augmentation

Leah Epstein, Rob van Stee
2006 Discrete Applied Mathematics  
Next, we give lower bounds for algorithms using resource augmentation on the speed. Finally, we consider scheduling with hard deadlines, and scheduling so as to minimize the total completion time.  ...  We use extra resource competitive analysis: an optimal off-line algorithm which schedules jobs on a single machine is compared to a more powerful on-line algorithm that has machines.  ...  The goal of an on-line algorithm is to minimize this ratio. Approximating the flow time is hard even in an off-line environment.  ... 
doi:10.1016/j.dam.2005.05.016 fatcat:fcmo6gwd5bdcvksp6biyysuioa

Optimal smoothing schedules for real-time streams

Yishay Mansour, Boaz Patt-Shamir, Ofer Lapid
2004 Distributed computing  
., we compare the weight delivered by on-line algorithms to the weight of an optimal off-line schedule using the same resources. We prove that a natural greedy algorithm is 2-competitive.  ...  We also prove a lower bound of 1:25 on the competitive ratio of any on-line algorithm.  ...  ., we compare on-line algorithms to optimal off-line schedules.  ... 
doi:10.1007/s00446-003-0101-0 fatcat:sjeyeykisnc3lgyf2zwtpxutru

Power-Aware Real-Time Scheduling upon Identical Multiprocessor Platforms [article]

Vincent Nélis, Joël Goossens, Nicolas Navet, Raymond Devillers and Dragomir Milojevic
2008 arXiv   pre-print
The second algorithm is an on-line and adaptive speed adjustment mechanism which reduces the energy consumption while the system is running.  ...  We propose two distinct algorithms. Our first algorithm is an off-line speed determination mechanism which provides an identical speed for each processor.  ...  Then, the algorithm searches the minimal speed by sweeping the value of k between 1 and m (line 4 to line 13).  ... 
arXiv:0712.2958v2 fatcat:cizc4p76vnchteqx6feoo2o4we

Distributed Real-Time Databases [chapter]

Ragunathan Rajkumar
1991 Synchronization in Real-Time Systems  
Mijn dank aan Jean Pierre Veen van de Stichting Technische Wetenschappen voor een soepele begeleiding van ons project.  ...  aan ons gebruikerscommittee. In die eerste fase hebben ze bijdragen geleverd die terug te vinden zijn in dit proefschrift.  ...  Classical off-line scheduling algorithms often require extensive amounts of infonnation to be available off-line. • On-line, announced.  ... 
doi:10.1007/978-1-4615-4000-7_4 fatcat:za4jxrd6gfalhjgwzq2r5qg5em

Robust Scheduling of Task Graphs under Execution Time Uncertainty

Michele Lombardi, Michela Milano, Luca Benini
2013 IEEE transactions on computers  
, as the PCP schedules exhibit good stability and improved average execution time (14% on average, up to 30% versus FPS and up to 40% versus the FIFO scheduler).  ...  The method has been tested on synthetic applications/platforms and compared with an off-line optimized Fixed Priority Scheduling (FPS) approach and a pure on-line FIFO scheduler; the results are very promising  ...  to meet real-time constraints (if any) and optimized for low average completion time.  ... 
doi:10.1109/tc.2011.203 fatcat:ivdcvgwpp5cspo3u6ktdu5ryve

Minimizing Maximum (Weighted) Flow-Time on Related and Unrelated Machines [chapter]

S. Anand, Karl Bringmann, Tobias Friedrich, Naveen Garg, Amit Kumar
2013 Lecture Notes in Computer Science  
In this paper we initiate the study of job scheduling on related and unrelated machines so as to minimize the maximum flow time or the maximum weighted flow time (when each job has an associated weight  ...  Our main results are: (i) We give an O(ε −3 )-competitive algorithm to minimize maximum weighted flow time on related machines where we assume that the machines of the online algorithm can process 1 +  ...  So, algorithm A must be able to process all the jobs. Off-line to on-line Now, we give an on-line algorithm for the instance I.  ... 
doi:10.1007/978-3-642-39206-1_2 fatcat:pygfqd25ijesrjjwaav45l7jmy

Minimizing Maximum (Weighted) Flow-Time on Related and Unrelated Machines

S. Anand, Karl Bringmann, Tobias Friedrich, Naveen Garg, Amit Kumar
2015 Algorithmica  
In this paper we initiate the study of job scheduling on related and unrelated machines so as to minimize the maximum flow time or the maximum weighted flow time (when each job has an associated weight  ...  Our main results are: (i) We give an O(ε −3 )-competitive algorithm to minimize maximum weighted flow time on related machines where we assume that the machines of the online algorithm can process 1 +  ...  So, algorithm A must be able to process all the jobs. Off-line to on-line Now, we give an on-line algorithm for the instance I.  ... 
doi:10.1007/s00453-015-0082-y fatcat:oxjfxyqzdfejxciazfmgkyeofm

Optimal smoothing schedules for real-time streams (extended abstract)

Yishay Mansour, Boaz Patt-Shamir, Ofer Lapid
2000 Proceedings of the nineteenth annual ACM symposium on Principles of distributed computing - PODC '00  
., we compare the weight delivered by on-line algorithms to the weight of an optimal off-line schedule using the same resources. We prove that a natural greedy algorithm is 4-competitive.  ...  We consider the problem of smoothing real-time streams (such as video streams), where the goal is to reproduce a variablebandwidth stream remotely, while minimizing bandwidth cost, space overhead, and  ...  ., we compare on-line algorithms to optimal off-line schedules.  ... 
doi:10.1145/343477.343511 dblp:conf/podc/MansourPL00 fatcat:viosp57jf5efpk5ljvywu7wvwu

Online Energy-Efficient Scheduling for Timely Information Downloads in Mobile Networks [article]

Yi-Hsuan Tseng, Yu-Pin Hsu
2019 arXiv   pre-print
Thus, in this paper we devise a randomized online scheduling algorithm for mobile devices, which can move arbitrarily and run the application for any amount of time.  ...  an optimal offline scheduling algorithm.  ...  Figs. 3 -5 display the time-average cost for the proposed Alg. 2 and the optimal offline scheduling algorithm.  ... 
arXiv:1901.03137v5 fatcat:tzufbqh2pzhlth5r6lj6s3rqtm
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