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Specification and Management of QoS in Real-Time Databases Supporting Imprecise Computations
March 2006 (vol. 55 no. 3)
pp. 304-319
Real-time applications such as e-commerce, flight control, chemical and nuclear control, and telecommunication are becoming increasingly sophisticated in their data needs, resulting in greater demands for real-time data services that are provided by real-time databases. Since the workload of real-time databases cannot be precisely predicted, they can become overloaded and thereby cause temporal violations, resulting in damage or even a catastrophe. Imprecise computation techniques address this problem and allow graceful degradation during overloads. In this paper, we present a framework for QoS specification and management consisting of a model for expressing QoS requirements, an architecture based on feedback control scheduling, and a set of algorithms implementing different policies and behaviors. Our approach gives a robust and controlled behavior of real-time databases, even for transient overloads and with inaccurate runtime estimates of the transactions. Further, performance experiments show that the proposed algorithms outperform a set of baseline algorithms that uses feedback control.

[1] D. Wu, Y.T. Hou, W.Z.Y.-Q. Zhang, and J.M. Peha, “Streaming Video over the Internet: Approaches and Directions,” IEEE Trans. Circuits and Systems for Video Technology, vol. 11, no. 3, pp. 282-300, Mar. 2001.
[2] S.-Y. Choi and A.B. Whinston, “The Future of e-Commerce: Integrate and Customize,” Computer, vol. 32, no. 1, pp. 133-134, Jan. 1999.
[3] J.W.S. Liu, W.-K. Shih, K.-J. Lin, R. Bettati, and J.-Y. Chung, “Imprecise Computations,” Proc. IEEE, vol. 82, Jan. 1994.
[4] S. Zilberstein and S.J. Russell, “Optimal Composition of Real-Time Systems,” Artificial Intelligence, vol. 82, nos. 1-2, pp. 181-213, 1996.
[5] X. Chen and A.M. K. Cheng, “An Imprecise Algorithm for Real-Time Compressed Image and Video Transmission,” Proc. Int'l Conf. Computer Comm. and Networks (ICCCN), 1997.
[6] M. Yannakakis, “Perspectives on Database Theory,” Proc. Ann. Symp. Foundations of Computer Science, 1995.
[7] S.V. Vrbsky and J.W.S. Liu, “APPROXIMATE— A Query Processor that Produces Monotonically Improving Approximate Answers,” IEEE Trans. Knowledge and Data Eng., vol. 5, no. 6, pp. 1056-1068 Dec. 1993.
[8] G.C. Buttazzo, Hard Real-Time Computing Systems. Kluwer Academic, 1997.
[9] J.L. Hellerstein, Y. Diao, S. Parekh, and D.M. Tilbury, Feedback Control of Computing Systems. Wiley-IEEE Press, 2004.
[10] S. Parekh, N. Gandhi, J. Hellerstein, D. Tilbury, T. Jayram, and J. Bigus, “Using Control Theory to Achieve Service Level Objectives in Performance Management,” Real-Time Systems, vol. 23, nos. 1/2, July/Sept. 2002.
[11] C. Lu, J.A. Stankovic, G. Tao, and S.H. Son, “Feedback Control Real-Time Scheduling: Framework, Modeling and Algorithms,” Real-Time Systems, vol. 23, nos. 1/2, July/Sept. 2002.
[12] M. Amirijoo, J. Hansson, and S.H. Son, “Algorithms for Managing QoS for Real-Time Data Services Using Imprecise Computation,” Proc. Conf. Real-Time and Embedded Computing Systems and Applications (RTCSA), 2003.
[13] M. Amirijoo, J. Hansson, and S.H. Son, “Error-Driven QoS Management in Imprecise Real-Time Databases,” Proc. Euromicro Conf. Real-Time Systems (ECRTS), 2003.
[14] G.F. Franklin, J.D. Powell, and M. Workman, Digital Control of Dynamic Systems, third ed. Addison-Wesley, 1998.
[15] Advances in Real-Time Systems, S.H. Son, ed., pp. 463-486. Prentice Hall, 1995.
[16] T. Gustafsson and J. Hansson, “Data Management in Real-Time Systems: A Case of On-Demand Updates in Vehicle Control Systems,” Proc. Real-Time Applications Symp. (RTAS), 2004.
[17] K. Ramamritham, “Real-Time Databases,” Int'l J. Distributed and Parallel Databases, no. 1, 1993.
[18] L.V. Fausett, Numerical Methods: Algorithms and Applications. Prentice Hall, 2003.
[19] N.J. Higham, Accuracy and Stability of Numerical Algorithms. SIAM, 1996.
[20] J. Chung and J.W. S. Liu, “Algorithms for Scheduling Periodic Jobs to Minimize Average Error,” Proc. Real-Time Systems Symp. (RTSS), 1988.
[21] R. Abbott and H. Garcia-Molina, “Scheduling Real-Time Transactions: A Performance Evaluation,” ACM Trans. Database System, vol. 17, pp. 513-560, 1992.
[22] K.J. Åström and B. Wittenmark, Adaptive Control, second ed. Addison-Wesley, 1995.
[23] K.-D. Kang, S.H. Son, and J.A. Stankovic, “Managing Deadline Miss Ratio and Sensor Data Freshness in Real-Time Databases,” IEEE Trans. Knowledge and Data Eng., vol. 16, no. 10, pp. 1200-1216, Oct. 2004.
[24] M.H. DeGroot and M.J. Schervish, Probability and Statistics, third ed. Addison-Wesley, 2002.
[25] J. Hansson, M. Thuresson, and S.H. Son, “Imprecise Task Scheduling and Overload Managment Using OR-ULD,” Proc. Conf. Real-Time Computing Systems and Applications (RTCSA), 2000.
[26] A. Bestavros and S. Nagy, “Value-Cognizant Admission Control for RTDB Systems,” Proc. Real-Time Systems Symp. (RTSS), pp. 230-239, 1996.
[27] T.-W. Kuo and S.-J. Ho, “Similarity-Based Load Adjustment for Static Real-Time Transaction Systems,” IEEE Trans. Computers, vol. 49, pp. 112-126, 2000.
[28] S. Davidson and A. Watters, “Partial Computation in Real-Time Database Systems,” Proc. Workshop Real-Time Software and Operating Systems, 1988.
[29] W. Hou, G. Ozsoyoglu, and B.K. Taneja, “Processing Aggregate Relational Queries with Hard Time Constraints,” Proc. ACM SIGMOD Int'l Conf. Management of Data, 1989.
[30] V. Lee, K. Lam, S.H. Son, and E. Chan, “On Transaction Processing with Partial Validation and Timestamps Ordering in Mobile Broadcast Environments,” IEEE Trans. Computers, vol. 51, no. 10, pp. 1196-1211, Oct. 2002.

Index Terms:
Real-time and embedded systems, real-time data services, imprecise computation, feedback control, modeling techniques.
Mehdi Amirijoo, J?rgen Hansson, Sang Hyuk Son, "Specification and Management of QoS in Real-Time Databases Supporting Imprecise Computations," IEEE Transactions on Computers, vol. 55, no. 3, pp. 304-319, March 2006, doi:10.1109/TC.2006.45
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