【作者】 孙冬璞；

【导师】 郝忠孝；

【作者基本信息】 哈尔滨理工大学 ， 计算机软件与理论， 2007， 硕士

【摘要】 时空数据库是在空间数据库和时态数据库的基础上发展而来的。由于时空数据库包含独有的数据形式,即移动对象,使得对时空数据库的研究要比对空间数据库和时态数据库的研究复杂的多。在时空数据库的关键研究问题中,时空数据的索引与查询占据着重要的位置。查询是数据库中的基本操作,所以查询的性能决定了数据库的性能,而要得到高的查询性能就必须建立一个好的索引机制,对于数据量庞大的时空数据库而言,建立一个高效的索引机制更是重中之重。首先介绍了时空数据库的相关知识,主要说明了时空数据库中移动对象的相关概念和理论,并分别对时空数据的查询与索引方法进行了归类。其次对现有的时空数据库的主要索引结构进行了研究与分析。主要介绍了R树及其变体的索引结构,重点对时空数据库中关于移动对象的索引方法进行了系统而全面的归类与总结,分析它们各自的主要设计思想和存在的优缺点。再次对最近邻查询问题进行了分类,并给出相应的定义,主要分析了静态对象的最近邻查询方法和移动对象的最近邻查询方法。最后提出了一种新的基于时空数据库中轨迹最近邻的索引结构,该索引结构在R树结构的基础上对其进行改进,并引入两个辅助存储结构,一个是动态存储移动对象最近邻信息的表结构,另一个是用来在查询中实现直接访问叶节点的辅助缓存结构。基于提出的索引结构,本文给出了时间片最近邻查询算法和时间段最近邻查询算法,并进行了性能评估。实验表明,由于辅助存储结构的引入,使得基于该索引结构的最近邻查询所需的时间大大减少,从而提高了最近邻查询的性能。更多还原

【Abstract】 The development of Spatio-Temporal Databases is based on the Spatial Databases and Temporal Databases. The research on Spatio-Temporal Databases is more complicated than that of the Spatial Databases and Temporal Databases because of the unique data form in Spatio-Temporal Databases—moving objects.The indexing and query in Spatio-Temporal Databases compose of the important part of the key research problems of Spatio-Temporal Databases. The performance of query determines that of Spatio-Temporal Databases because query is the primary operation in Databases. Moreover, a good indexing mechanism also determines high performance of query. Establishing an indexing mechanism with high performance is the most important thing to Spatio-Temporal Databases with a large number of data.Firstly, we introduce the relative knowledge about Spatio-Temporal Databases, and explain the relative conception and theory. At the same time, the indexing and query methods of Spatio-Temporal Databases are classified, respectively.Secondly, we research and analyze the existing main indexing structures in Spatio-Temporal Databases. we mainly introduce the R-tree variants, and emphatically, classify and summarize systematically and completely the indexing methods for moving objects in Spatio-Temporal Databases, and analyze the main ideas and existing advantages and drawbacks, respectively. Thirdly, we classify the problems of the nearest neighbor query, and give the definition accordingly. The nearest neighbor query methods for static objects and those for moving objects are mainly analyzed. Last, we propose a new indexing structure for trajectories’nearest neighbors based on Spatio-Temporal Databases. This indexing structure is improved from R-trees. It introduces two auxiliary storage structures. One is list structure for dynamic storing the nearest neighbors information of moving objects, and the other is auxiliary cache for accessing directly leaf nodes. According to the indexing structure, the time-slice nearest neighbor query algorithm and interval nearest neighbor query algorithm are proposed, and the performance evaluation is given. The experiment shows that because of the introduction of the two auxiliary storage structures, the nearest neighbor query time is reduced significantly, and therefore, the performance of the nearest neighbor query based on the indexing structure is improved.更多还原