Abstract: The uncertainty of mobile objects is inherent due to the inaccuracy of data acquisition equipments, delayed update of mobile objects, privacy protection and so on. As a result of extending the traditional database with probability dimension, the ways to describe the objects, define the queries, process the queries and present the answer results have changed. And the traditional querying methods over precise data are inapplicable for the queries over uncertain data. Therefore, the query processing techniques over uncertain mobile objects have attracted more and more attention, and become one of the hot topics in the field of database. This paper discusses the challenges of the query processing over uncertain mobile objects, and summarizes the existing work on the range query, nearest neighbor query, reverse nearest neighbor query and trajectory query over uncertain mobile objects. Finally, this paper explores the research focus and the trend of this area.

Key words: uncertain data, mobile objects, range query, nearest neighbor query, reverse nearest neighbor query

摘要： 由于数据采集设备不精确，移动对象延迟更新和隐私保护等原因，移动对象的不确定性普遍存在。在传统数据库中增加概率维，使得对象表达、查询定义、查询处理以及最终结果的呈现，都与传统方法不同，基于确定数据的移动对象查询处理技术无法进行有效处理。因此，基于不确定对象的查询处理技术受到越来越多的关注，成为当前数据库领域的研究热点问题之一。讨论了不确定对象查询面临的挑战；从查询定义、剪枝策略和算法等角度，分别对基于不确定移动对象的范围查询、最近邻查询、反最近邻查询和轨迹查询的研究现状进行了详细的介绍和对比；探讨了今后的研究重点和发展趋势。

关键词: 不确定数据, 移动对象, 范围查询, 最近邻查询, 反最近邻查询