Abstract: In Distributed Data Stream Management Systems，operators are executed in different processing nodes.It is a critical issue to determine operator placement in Distributed Data Stream Management Systems.An operator placement algorithm based on latency space and spring relaxation technology is proposed by Peter et al.But the algorithm assumes that the data race between two operators is constant and doesn’t consider the relativity between the data race of data streams and operator.Therefore this paper analyses the relation between the operator and its output race of data stream，and improves upon the algorithm proposed by Peter et al.Experimental results show that the algorithm can be applied to distributed data stream management systems effectively.

摘要： 在分布式数据流管理系统中，需要将查询操作放置到不同的处理结点执行。因此，如何放置查询操作成为分布式数据流管理研究的核心问题。Peter等人提出一种基于时延空间和弹簧张弛技术的查询操作放置算法，但是该算法假设查询操作之间数据流的流速不变，没有考虑数据流的流速与数据流查询操作之间的相关性。为此，通过分析不同的数据流查询操作与其输出的数据流的流速之间的关系，对Peter等人提出的算法加以改进，实验结果表明，改进后的算法可以有效地应用于分布式数据流管理系统。