Research on 3D Moving Object Databases

本研究探讨一个能有效回应人、车等移动物件之各种查询的移动物件资料库系统的理论与实务。首先，我们提出了一种能够描述运动对象时空特性的运动对象数据模型。它不仅描述了运动物体的质心位置，而且还描述了运动物体的方向和姿态作为运动数据，它还描述了运动物体的轨道以及两个运动物体之间的空间关系，如距离、相互方向和拓扑关系。我们提出了一种移动对象查询语言MOQL，通过它我们可以指定各种对象的移动。然而，我们发现，当我们使用WOOL来指定一个动态移动时，比如一个像这样移动的对象移动，有一个困难。为了解决这个问题，我们引入了一个运动捕捉系统来捕捉一个对象的移动作为一个样本移动，系统可以检索一组对象的移动类似于这个样本。介绍了两个运动对象的恒等式、基本相似性、部分相似性、时间规整下的相似性和时空相似性。结果表明，我们的基本相似性定义可以区分两个物体运动的速度不同的模式，但有相同的轨道。然而，它也表明，我们必须引入一种新的类型的相似性定义，可以区分运动物体的速度模式。结果表明，基于时间规整的相似性的定义时，一个对象移动被划分为一组组件对象的工作更好。

This research investigated a theory and practice of a moving object database system that is rile to answer to a variety of queries on moves of moving objects such as human and automobiles. First we proposed a moving object data model that can describe the spatio-temporal characteristics of moving objects. It describes not only the centroid position of a moving object but also its direction and orientation as the data of move, it also describes the orbit of a moving object as well as the spatial relationships between two moving objects such as the distance, the mutual direction and the topological relationship. We proposed a moving object query language named MOQL by which we can specify a variety of object moves. However, we found that there was a difficulty when we use WOOL to specify a dynamic move such as an object move moving like this. In order to resolve this problem, we introduce a motion capturing system to capture an object move as a sample move by which the system can retrieve a set of objects whose move are similar to this sample. We have introduced the identity, the basic similarity, the partial similarity, the similarity under time warping, and the spatio-temporal similarity of two moving objects. As a result it is shown that our basic similarity definition can distinguish two object move shaving different moving speed patterns but have the same orbit. However, it is also revealed that we must introduce a new type of a similarity definition that can distinguish the speed patterns of moving objects. It is shown that the definition of the similarity based on time warping works better when an object move is divided into a set of component objects.