Studies on a Dynamic Scheduling Method in Distributed Real-Time System

在本财年。提出了一种运行前调度方法，并结合仿真结果讨论了该方法的有效性。此外，我们还提出了一种基于资源预留的动态调度方法，并讨论了它在实时事务调度中的应用。1.端到端时间约束的分布式实时系统调度算法在本研究中，我们提出了一种端到端时间约束、抖动约束等多种时间约束的分布式实时系统调度算法。该算法具有调度满足各种约束条件的网络和处理器的能力，适用于具有不需要实时通信设施的网络的系统。仿真研究表明，该算法在取得较高成功率的同时，具有很高的效率。一种基于资源预留的实时同步协议和调度方法在本研究中，我们提出了一种基于时间戳排序的实时事务动态同步协议和调度方法。首先，在这项研究中。提出了通过预留共享资源来防止事务中止的同步协议，并提出了基于时间戳排序和优先级的动态事务调度方法。这种方法使得减少交易的截止日期错失成为可能。最后，给出了所提方法和其他方法的仿真结果，并讨论了所提方法的有效性。

In this fiscal year. we have developed a pre-runtime scheduling method and discussed its effectiveness based on simulation results of it and other methods. Furthermore, we have developed a dynamic scheduling method based on the resource reservation and discussed its applications to the scheduling of real-time transactions. These results are summarized as follows :1. A scheduling algorithm for distributed real-time systems with end-to-end timing constraintsIn this research, we have developed a scheduling algorithm for distributed real-time systems with various timing constraints such as end-to-end timing constraints and jitter constraints. The proposed algorithm has capability to schedule networks as well as processors satisfying various constraints and is applicable to the systems with networks which need not have real-time commimication facilities. Simulation study shows that the proposed algorithm is very efficient while achieving high success ratio.2. A real-time synchronization protocol and scheduling method based on the resource reservationIn this research, we have developed a dynamic synchronization protocol and scheduling method based on time-stamp ordering for real-time transactions. First, in this research. the synchronization protocol which prevents transaction abortions by reservation of shared resources is developed, Next, in this research, the dynamic transaction scheduling method based on timestamp ordering and priority is developed. This method makes it possible to decrease the deadline miss of transactions. Finally, in this research, simulation results of proposed and other methods are presented and efficiency of proposed methods are discussed.