摘要
针对时移电视(time-shifted TV)节目流行度变化剧烈的特点,提出一种改进的最小负载优先(SLF)放置算法.算法以放置更多副本为目标,修改了放置约束,并以双阈值动态调整作为辅助策略,降低了流行度变化对系统负载均衡的影响.仿真结果表明,该策略可有效降低用户请求拒绝率,改善系统性能,特别是在实际点播与预测不符时效果更为明显.
An improved smallest load first （SLF） placement algorithm is proposed, which focuses on the sharp changes of popularity of time-shifted TV. With an objective of maximizing the number of replicas of each video, the placement constraints are changed, and dual-threshold dynamic adjustment is used as an assistant policy. As a result, the effect of popularity changes on the system load balance is reduced. Simulation results reveal that, with the proposed policy, the user request reject rate is reduced, and the system performance is improved, especially when the actual demand is not coincident with the expectation.
出处
《信息与控制》
CSCD
北大核心
2009年第1期93-97,共5页
Information and Control
基金
国家863计划资助项目(2007AA01Z235)
新世纪优秀人才支持计划资助项目(NCET-04-0564)
安徽省优秀青年科技基金资助项目(08040106910)
中国科学技术大学研究生创新基金资助项目(KD2008063).
关键词
时移电视
存储调度
副本放置
最小负载优先
负载平衡
time-shifted TV
storage scheduling
replica placement
smallest load first （SLF）
load balance
