Performance guarantee for online deadline scheduling in the presence of overload

Earliest deadline first (EDF) is a widely-used online algorithm for scheduling jobs with deadlines in real-time systems. Yet, existing results on the performance guarantee of EDF are limited to underloaded systems [6,12,14]. This paper initiates the study of EDF for overloaded systems, attaining similar performance guarantees as in the underloaded setting. Specifically, we show that EDF with a simple form of admission control is optimal for scheduling on both uniprocessor and multiprocessors when moderately faster processors are available (our analysis actually admits a tradeoff between speed and extra processors). This is the first result attaining optimality under overload. Another contribution of this paper is an improved analysis of the competitiveness for weighted deadline scheduling.published_or_final_versio

Breast cancer and screening in Hong Kong: Letter to the editor

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A tighter extra-resource analysis of online deadline scheduling

This paper is concerned with online algorithms for scheduling jobs with deadlines on a single processor. It has been known for long that unless the system is underloaded, no online scheduling algorithm can be 1-competitive, i.e., matching the performance of the optimal offline algorithm. Nevertheless, recent work has revealed that some online algorithms using a moderately faster processor (or extra processors) can guarantee very competitive performance Kalyanasundaram and Pruhs, 2000 or even be 1-competitive Koo et al., 2002; Lam and To, 2001. This paper takes a further step to investigate online scheduling algorithms with an even higher performance guarantee (i.e., better than 1-competitive algorithms) and in particular, presents an extra-resource analysis of the earliest-deadline-first strategy (EDF) with respect to such a higher performance guarantee. © 2005 Springer Science + Business Media, Inc.postprin

Pixel super-resolution in optical time-stretch microscopy using acousto-optic deflector

Session - Biosensing and Bio-Manipulation Techniques II (BW2A): paper BW2A.7Bio-Optics: Design and Application (BODA)We present experimental demonstration of pixel super-resolution time-stretch imaging by high-speed agile-beam-steering with the use of synchronized acousto-optic deflector--enabling high-resolution imaging rate of 1MHz whereas relaxing the stringent requirement on extreme data acquisition. © 2015 OSApostprin

The use of Stunkard’s figure rating scale to identify underweight and overweight in Chinese adolescents

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Extra processors versus future information in optimal deadline scheduling

This paper is concerned with the extra-resource analysis of online scheduling algorithms. In particular, it studies how to make use of multiple processors to counteract the lack of future information in online deadline scheduling. Our results extend the previous work that are primarily based on using a faster processor to obtain a performance guarantee. The challenge arises from the fact that jobs are sequential in nature and cannot be executed on more than one processor at the same time. Thus, a faster processor can speed up a job while multiple unit-speed processors cannot help.postprin

Competitive deadline scheduling via additional or faster processors

This paper studies on-line scheduling in a single-processor system that allows preemption. The aim is to maximize the total value of jobs completed by their deadlines. It is known that if the on-line scheduler is given a processor faster (say, two times faster) than the off-line scheduler, then there exists an on-line algorithm called SLACKER that can achieve an O(1) competitive ratio. In this paper, we show that using additional unit-speed processors instead of a faster processor is a possible but not cost effective way to achieve an O(1) competitive ratio. Specifically, we find that-θ(log k) unit-speed processors are required, where k is the importance ratio. Another contribution of this paper is an improved analysis of the competitiveness of SLACKER; this new analysis enables us to show that SLACKER, when extended to multi-processor systems, can still guarantee an O(1) competitive ratio.postprin

Promotor hypermethylation of the CpG Islands of human Ras Association Domain Family 1A gene (RASSF1A) in adenocarcinoma of lung in Hong Kong Chinese - a comparison between smokers and non-smokers

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Efficient rotation- and scale-invariant texture analysis

Author name used in this publication: Kin-Man Lam2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Effects of treatment of acromegaly with Sandostatin® LAR® on lipolytic enzymes and cholesteryl ester transfer protein activities

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