大数据时代下,移动互联网发展与移动终端的普及形成了海量移动对象轨迹数据.轨迹数据含有丰富的时空特征信息,通过轨迹数据处理技术,可以挖掘人类活动规律与行为特征、城市车辆移动特征、大气环境变化规律等信息.海量的轨迹数据也潜在性地暴露出移动对象行为特征、兴趣爱好和社会习惯等隐私信息,攻击者可以根据轨迹数据挖掘出移动对象的活动场景、位置等属性信息.另外,量子计算因其强大的存储和计算能力成为大数据挖掘重要的理论研究方向,用量子计算技术处理轨迹大数据,可以使一些复杂的问题得到解决并实现更高的效率.对轨迹大数据中数据处理关键技术进行了综述.首先,介绍轨迹数据概念和特征,并且总结了轨迹数据预处理方法,包括噪声滤波、轨迹压缩等;其次,归纳轨迹索引与查询技术以及轨迹数据挖掘已有的研究成果,包括模式挖掘、轨迹分类等;总结了轨迹数据隐私保护技术基本原理和特点,介绍了轨迹大数据支撑技术,如处理框架、数据可视化;也讨论了轨迹数据处理中应用量子计算的可能方式,并且介绍了目前轨迹数据处理中所使用的核心算法所对应的量子算法实现;最后,对轨迹数据处理面临的挑战与未来研究方向进行了总结与展望.
The development of mobile internet and the popularity of mobile terminals produce massive trajectory data of moving objects under the era of big data.Trajectory data has spatio-temporal characteristics and rich information.Trajectory data processing techniques can be used to mine the patterns of human activities and behaviors,the moving patterns of vehicles in the city and the changes of atmospheric environment.However,trajectory data also can be exploited to disclose moving objects' privacy information (e.g.,behaviors,hobbies and social relationships).Accordingly,attackers can easily access moving objects' privacy information by digging into their trajectory data such as activities and check-in locations.In another front of research,quantum computation presents an important theoretical direction to mine big data due to its scalable and powerful storage and computing capacity.Applying quantum computing approaches to handle trajectory big data could make some complex problem solvable and achieve higher efficiency.This paper reviews the key technologies of processing trajectory data.First the concept and characteristics of trajectory data is introduced,and the pre-processing methods,including noise filtering and data compression,are summarized.Then,the trajectory indexing and querying techniques,and the current achievements of mining trajectory data,such as pattern mining and trajectory classification,are reviewed.Next,an overview of the basic theories and characteristics of privacy preserving with respect to trajectory data is provided.The supporting techniques of trajectory big data mining,such as processing framework and data visualization,are presented in detail.Some possible ways of applying quantum computation into trajectory data processing,as well as the implementation of some core trajectory mining algorithms by quantum computation are also described.Finally,the challenges of trajectory data processing and promising future research directions are discussed.