移动对象管理的特征 Coordinate-based queries 口 point o range a nearest-neighbor queries Trajectory-based Queries a topological queries: enter, leave, cross, and bypass a navigational queries using derived information, e.g., speed Continuous Queries challenge a Continuous update of the position5 移动对象管理的特征 ◼ Coordinate-based Queries ❑ point, ❑ range ❑ nearest-neighbor queries ◼ Trajectory-based Queries ❑ topological queries: enter, leave, cross, and bypass ❑ navigational queries using derived information, e.g., speed ◼ Continuous Queries ◼ Challenge ❑ Continuous update of the position