Designing, Querying and Implementing Spatiotemporal Databases

9302244斯诺德格拉斯这是为期三年的持续奖励的第一年资助。许多新兴应用，包括地理信息系统和科学数据库，如与全球变化研究有关的应用，都需要同时支持空间和时间数据。该项目考虑了三个领域，在这些领域中，需要推广以前提出的分别处理空间或时间的方法，以产生一个连贯的时空(ST)数据库方法。第一个问题是ST数据库的设计。数据库管理员使用数据模型来描述要建模的企业。使用时间瞬间集的时态数据库中使用的概念性数据模型正在与空间数据库中使用的点集模型合并。第二个问题是查询处理，特别是ST自然连接和ST聚合的高效执行。目前提出的时间查询处理方法的扩展正在开发中。最后，必须处理ST不确定性，即“不知道确切的地点或时间”的信息。同样，合并的数据模型非常有用，因为可以将该模型中的不确定性建模为可能的时刻和点的集合。其结果将是改进设计科技数据库和实施科技数据库管理系统的方法，其中时间和空间支助是平衡和协调的。***

9302244 Snodgrass This is the first year funding of a three-year continuing award. Many emerging applications, including geographical information systems and scientific databases, such as those associated with global change studies, require simultaneous support for spatial and temporal data. This project considers three areas where previously proposed approaches for handling space or time separately need to be generalized to produce a coherent approach to spatiotemporal (ST) database. The first issue is the design of ST databases. Database administrators use a data model to describe the enterprise to be modeled. A conceptual data model used in temporal databases that employs sets of time instants is being merged with the point set model used in spatial databases. The second issue is that of query processing, specifically efficient execution of ST natural joins and ST aggregates. Extensions of currently proposed temporal query processing methods are under development. Finally, ST indeterminacy, or "don't know exactly where or when" information, must be handled. Again, the merged data model is quite helpful, as it is possible to model indeterminacy in this model as sets of possible instants and points. The result will be enhanced methods of designing ST databases and implementing ST database management systems, in which time and space support is balanced and coordinated. ***