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Issue No. 09 - Sept. (2012 vol. 61)
ISSN: 0018-9340
pp: 1325-1340
Hongya Wang , Sch. of Comput. Sci. & Technol., Donghua Univ., Shanghai, China
Yingyuan Xiao , Sch. of Comput. & Commun. Eng., Tianjin Univ. of Technol., Tianjin, China
LihChyun Shu , Dept. of Accountancy, Nat. Cheng Kung Univ., Tainan, Taiwan
On-demand broadcast is a promising data dissemination approach in mobile computing environments thanks to its adaptability and scalability for large-scale and dynamic workload. An important class of emerging data broadcast applications needs to monitor multiple time-varying data items continuously to be kept aware of the up-to-date information. This paper investigates the broadcast schedule problem for disseminating timely data to periodic continuous queries, and a systematic and highly efficient solution for applications of this type is provided. In particular, we propose a novel measure, called Bandwidth Utilization, to quantify the minimum bandwidth demand of a periodic continuous query set. The timing predictability can be ensured if a set of periodic continuous queries passes a bandwidth utilization based schedulability test. The schedulability test techniques are also extended to deal with dynamic query arrival and departure. An efficient online scheduling algorithm, called RM-UO, is developed, which can fulfill the timing constraints combined with the proposed query release and deletion policies. To demonstrate the effectiveness of theoretical results, an illustrative algorithm implementation is presented along with comprehensive performance analysis. Simulation results show that our solution offers nice timing predictability whereas other comparable best effort scheduling algorithms such as SIN-Q and DTIU experience different deadline miss ratios at different query workloads.
scheduling, bandwidth allocation, broadcasting, mobile computing, performance evaluation, query processing, deadline miss ratios, periodic continuous query scheduling, real-time data broadcast environments, on-demand broadcast, data dissemination approach, mobile computing, large-scale query workload, dynamic query workload, broadcast scheduling problem, timely data dissemination, bandwidth utilization, periodic continuous query set, schedulability test, dynamic query arrival, dynamic query departure, online scheduling algorithm, RM-UO algorithm, timing constraints, query release policies, query deletion policies, timing predictability, best effort scheduling algorithms, SIN-α algorithms, DTIU algorithms, Bandwidth, Real time systems, Schedules, Timing, Mobile communication, Scheduling algorithm, Servers, real-time scheduling., Data broadcast, periodic continuous query processing

Yingyuan Xiao, Hongya Wang and LihChyun Shu, "Scheduling Periodic Continuous Queries in Real-Time Data Broadcast Environments," in IEEE Transactions on Computers, vol. 61, no. , pp. 1325-1340, 2012.
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