Imprecise Computations with Deferred Optional Tasks

The imprecise computation model is an extension of the traditional real-time processing model. In this model, each imprecise task is logically divided into two portions: a mandatory portion and an optional portion. Since the optional portions of imprecise tasks can be traded for their deadlines and/or the required quality of service (QoS), the resulting quality of executing tasks in this model can be controlled by different strategies of the scheduling algorithms. In this paper, we present two significant results pertaining to on-line scheduling problems in the model of imprecise computation obeying Deferred Optional Tasks (DOT) scheduling discipline. The first significant result presented is, to the best of our knowledge, the very first proof of NP-hardness property for the problem of on-line, imprecise DOT scheduling without preemption (DOTwoP). And the second one is that we propose an O(nlog^2n) algorithm to solve the problem of on-line, imprecise DOT scheduling with preemption (DOTwP) when tasks are ready upon arrival.

[1]  Wei-Kuan Shih,et al.  Algorithms for Scheduling Imprecise Computations with Timing Constraints to Minimize Maximum Error , 1995, IEEE Trans. Computers.

[2]  Gihyun Jung,et al.  Performance evaluation of on-line scheduling algorithms for imprecise computation , 1998, Proceedings Fifth International Conference on Real-Time Computing Systems and Applications (Cat. No.98EX236).

[3]  Jörgen Hansson,et al.  Algorithms for Managing QoS for Real-Time Data Services Using Imprecise Computation , 2003, RTCSA.

[4]  Wei-Kuan Shih,et al.  A fast algorithm for scheduling imprecise computations with timing constraints to minimize weighted error , 2000, Proceedings 21st IEEE Real-Time Systems Symposium.

[5]  Wen Gao,et al.  Imprecise computation scheduling on scalable media stream delivery , 2003, Fourth International Conference on Information, Communications and Signal Processing, 2003 and the Fourth Pacific Rim Conference on Multimedia. Proceedings of the 2003 Joint.

[6]  Cheng-Chew Lim,et al.  Overload Management by Imprecise Computation , 1995 .

[7]  Wei-Kuan Shih,et al.  Software radio system design for accessing wireless multimedia services , 2001 .

[8]  Riccardo Bettati,et al.  Imprecise computations , 1994, Proc. IEEE.

[9]  Wei-Kuan Shih,et al.  Fast algorithms for scheduling imprecise computations , 1989, [1989] Proceedings. Real-Time Systems Symposium.

[10]  Sanjoy K. Baruah,et al.  Competitive on-line scheduling of imprecise computations , 1996, Proceedings of HICSS-29: 29th Hawaii International Conference on System Sciences.

[11]  Wei-Kuan Shih,et al.  On-Line Scheduling of Imprecise Computations to Minimize Error , 1996, SIAM J. Comput..

[12]  G. Drozdy,et al.  Introduction to the global system for mobile communications , 1995 .

[13]  Albert Mo Kim Cheng,et al.  An imprecise algorithm for real-time compressed image and video transmission , 1997, Proceedings of Sixth International Conference on Computer Communications and Networks.

[14]  Nobuyuki Yamasaki,et al.  RT-Frontier: a real-time operating system for practical imprecise computation , 2004, Proceedings. RTAS 2004. 10th IEEE Real-Time and Embedded Technology and Applications Symposium, 2004..

[15]  Wei-Kuan Shih,et al.  Scheduling imprecise computations to minimize total error , 1989, Microprocessing and Microprogramming.