FYTG 5101 Presentation

Data Management For Spatio-temporal Data Of PM 2.5 Indices Through Mobile SensingType of This Project: Survey

Yun Wen

Outlines

• Motivation• ST Concepts and Models• Storage Structure and Indexing

Reliable?

Project: Home Air Quality Sensor Network

CO,O2,PM2.5Smoke,TempHumidity

+Electricity Consumption

Spatiotemporal Data

Spatiotemporal Data

SpatioTemporal DataBase Management System

• Temporal DBMS: existance time, valid-time, transaction-time

• Spatial DBMS: GIS, environmental information system, trajectory and multimedia

ER Temporal

ER Spatial

ER SpatioTemporal

Storage Structure and Indexing

1D database indexing structures are not appropriate• Quad trees• K-D-B trees• R-tree• …..

Quad tree

Quad tree

Type of Data:• region quadtree• point quadtree• Lines/curves quadtreeNode Information:• Four pointers

(NW,NE,SW,SE)• Point: key(x,y);value

Quad tree

Do not take paging of secondary memory into accountTemporal:Linear Quadtree

Improved: Overlapping Linear Quadtree

K-D-B tree

K-D-B tree

Region pages (region,child) + point pages(point,location)

• Same path length • Disjoint page• Union of all region in the

child is region

K-D-B tree

Designed for paged memory, but are useful only for point data

B+ tree

R tree

• A B+ tree

R tree

R tree

Balanced-search treeOrganize data in pageOverlapped regionn entries M maximum

Variants:Hilbert R-treeX-treeR* tree, R+ tree

Conclusion

• All trees are important• Trade-off