A time series dataset is a sequence of random variables indexed by time.
时间序列数据是以时间为指标的一个随机变量序列。
2
A variable can represent an array if it has to store an indexedset of closely related data items.
如果变数需要储存一组关系密切的资料项目索引，则可代表一个阵列。
3
A database system in which most of the data are spatially indexed, and upon which a set of procedures operated in order to answer queries about spatial entities in the database.