基于分形技术的数据流突变检测算法

Fractal-Based Algorithms for Burst Detection over Data Streams

数据流上的突变检测技术由于其在风险分析、网络监测、趋势分析等领域广阔的应用前景而受到学术界和工业界越来越多的关注.为了在数据流上检测多个滑动窗口上的单调聚集函数值和非单调聚集函数值的突变,提出了基于分形技术的构建单调搜索空间的突变检测算法.首先给出了数据流上的分段分形模型,进而基于该模型设计了突变检测算法.该算法能够将突变检测处理时间复杂度从O(m)降为O(logm)(m为需要被检测的滑动窗口数目).提出的两种新颖的分段分形模型能够准确地对数据流的自相似性进行建模并压缩数据流.理论分析和实验结果表明,与已有研究成果相比,算法具有较高的精度和较低的时间/空间复杂度,更加适用于进行数据流的突变检测.

Burst detection over data streams has been attracting more and more attention from academic and industry communities due to its broad potential applications in venture analysis, network monitoring, trend analysis and so on. This paper aims at detecting bursts of both monotonic and non-monotonic aggregates over multiple windows in data streams. A burst detection algorithm through building monotonic search space based on fractal technique is proposed. First, the piecewise fractal model on data stream is introduced, and then based on this model the algorithm for detecting bursts is presented. The proposed algorithm can decrease the time complexity from O（m） to O（logm）, where m is the number of sliding windows being detected. Two novel piecewise fractal models can model the self-similarity and compress data streams with high accuracy. Theoretical analysis and experimental results show that this algorithm can achieve a higher precision with less space and time complexity as compared with the existing methods, and it could be concluded that the proposed algorithm is suitable for burst detection over data streams.