To fulfill the requirements for hybrid real-time system scheduling, a long-release-interval-first （LRIF） real-time scheduling algorithm is proposed. The algorithm adopts both the fixed priority and the dynamic prior...
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To fulfill the requirements for hybrid real-time system scheduling, a long-release-interval-first （LRIF） real-time scheduling algorithm is proposed. The algorithm adopts both the fixed priority and the dynamic priority to assign priorities for tasks. By assigning higher priorities to the aperiodic soft real-time jobs with longer release intervals, it guarantees the executions for periodic hard real-time tasks and further probabilistically guarantees the executions for aperiodic soft real-time tasks. The schedulability test approach for the LRIF algorithm is presented. The implementation issues of the LRIF algorithm are also discussed. Simulation result shows that LRIF obtains better schedulable performance than the maximum urgency first （MUF） algorithm, the earliest deadline first （EDF） algorithm and EDF for hybrid tasks. LRIF has great capability to schedule both periodic hard real-time and aperiodic soft real-time tasks.
信息资源在分发共享过程中存在带宽拥塞、内容冗余等问题,播存网络借助"一点对无限点"的物理广播分发共享信息资源,对解决此类问题有独特优势.播存网络采用统一内容标签(uniform content label,UCL)适配用户兴趣和推荐信息资源,用户如何高效地获得自己感兴趣的UCL是播存网络中的关键问题.针对该问题,提出一种播存网络环境下的UCL协同过滤推荐方法(unifying collaborative filtering with popularity and timing,UCF-PT).首先,通过设定一对相似度阈值来计算用户与UCL数据的稀疏情况,根据稀疏情况决定二者对UCL评分的影响权值,并基于二者权值预测用户对UCL的评分,生成推荐结果集.其次,依据UCL热度调整推荐结果集的UCL顺序,从而使热门UCL更容易推荐给用户;最后提出UCL价值衰减函数,保证较新的UCL具备较高的推荐优先级.实验结果表明:与传统推荐方法相比,该方法不仅具有良好的推荐精度,还可保证所推荐UCL的热度与时效性,更适用于在播存网络环境下推荐UCL.
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