ABSTRACT Moving objects databases store and process objects with a focus on their spatiotemporal behaviour. To achieve this, the model of the data must be suitable to efficiently store and process moving objects. Currently, a unit-based model is widely used, where each moving object is divided into one or more time intervals, during which the object behaves uniformly. This model is also used for a data type called moving regions, which resembles moving and shape changing regions as, for example, forest fires or cloud fields. However, this model struggles to support operations like union, difference or intersection of two moving regions; the resulting objects are unnecessarily bloated and uncomfortable to handle because the resulting number of units is generally very high. In this paper, an alternative model for moving regions is proposed, which is based on polyhedra. Furthermore, this work develops an isomorphism between moving regions and polyhedra including all relevant operations, which has the additional advantage that several implementations for those are already readily available; this is demonstrated by a reference implementation using the existing and well-tested Computational Geometry Algorithms Library (CGAL).

中文翻译：

---

基于多面体的数据库移动区域模型

摘要 移动对象数据库存储和处理对象，重点是它们的时空行为。为此，数据模型必须适用于有效存储和处理移动对象。目前，基于单元的模型被广泛使用，其中每个运动对象被划分为一个或多个时间间隔，在此期间对象的行为是一致的。该模型还用于称为移动区域的数据类型，它类似于移动和形状变化的区域，例如森林火灾或云场。但是，该模型难以支持两个移动区域的联合、差异或交集等操作；生成的对象不必要地臃肿且处理起来不舒服，因为生成的单元数通常非常高。在本文中，提出了一种用于移动区域的替代模型，这是基于多面体。此外，这项工作开发了移动区域和多面体之间的同构，包括所有相关操作，这具有额外的优势，即这些操作的几种实现已经很容易获得；这通过使用现有且经过良好测试的计算几何算法库 (CGAL) 的参考实现来证明。