fall 2000cs 599 – spatial and temporal databases research issues in spatio- temporal database...

Fall 2000 CS 599 – Spatial and Temporal Databases

Research Issues in Spatio-temporal Database Systems

Timos Sellis

Presented byHandy Patriawan


Introduction Common techniques and tools

R-Tree for both Spatial and Temporal Join Spatial and Temporal into one

Proposed name: STDBMSs Spatio-temporal DBMSs

Current application Geographic Information Systems (GIS) Environmental Information System Multimedia


Introduction (cont’d) Examples:


Introduction (cont’d) CHOROCHRONOS

http://www.chorochronos.com Issues to be addressed:

Ontology, structure and representation of space and time

Data model and query language GUI Query processing, storage and indexing

techniques Architecture


Introduction (cont’d) Extension of Spatial or Temporal

DBMSs is not enough Adding Temporal support to SDBMSs Adding Spatial support to TDBMSs

Final frontier: unified Spatio-temporal DBMS Spatio-temporal data structures,

operators and user-interfaces


Issues… Ontological Issues

Ontology: the study or concern about what kinds of things exist – what entity there are in the universe (http://www.whatis.com)

Including Structure and Representation Finding a common framework

• E.g. common structure and representation


Issues… Ontological Issues (cont’d)

• Ontology of spatial entities: life and motion


Region

Issues… Ontological Issues (cont’d)

• Spatial objects are located “somewhere” in space

ObjectPart Location


Issues… Models and Languages for STDBMSs

Focus on 3 topics:• Language for spatio-temporal relations• Models and languages for STDBMSs• Design and techniques for STDBMSs

Research is divided into 2 categories:• Tight integration of spatial & temporal• Adding spatial support to temporal


Issues… Different classes of applications

Events in space & time, Moving region, etc.

See [4] for more details Different data structures &

operations has been defined as well (see [4]) E.g. mpoint x mpoint -> mreal:distance


Issues… Constraint database models

Development in spatio-temporal constraint-based database model

Example: DEDALE• Prototype of a constraint DBMS for spatio-temporal

information• See http://www-rocq.inria.fr/verso/dedale/• See http://sikkim.cnam.fr/dedale.html

• Still based on SQL• Display the parts of roads which is inside the rectangle RECT

drawn on the screen• Select SELECT(r.geometry, RECT)

From r in RoadsWhere Satisfy(SELECT(r.geometry, RECT))


Issues… Extending current SQL

STSQL Allowing relations to have attributes that are

spatial or temporal Not intended for movement of continuously

moving or changing objects

t=nt=n+1

t=n+2X

Y


Proposed Indexing for Moving Object “Indexing the Positions of Continuously Moving

Objects” Simonas Saltenis, Christian S. Jensen, Scott T.

Leutenegger and Mario A. Lopez Issues: How can we index a moving object (and or

changing object) during time periods? Proposed solution:

• R*-Tree with time as parameter (boring….)• Function…


Function for Indexing Moving Objects

t=nX

Y

Time Function

n Y=X

Y=X

t=n+1

n+1

Y=X-2

Y=X-2

t=n+2

n+2 Y=3

Y=3


Storage, Indexing and Querying Storage and Indexing:

Support for motion Benchmarking

Indexing: R-Tree, Quadtree, etc. Benchmark:

Make sure to include everything needed Test access method, data generation, query

processing and result analysis ---> Common platform for benchmarking the

STDBMS as a whole


Storage, Indexing and Querying Query processing and optimization:

Efficient access for spatial, temporal and spatio-temporal

Simple cost model for query optimization

Study of spatial and temporal constraint database


Conclusion Good progress… still more work is

needed: Devising clean and complete semantics

for data models and operators Efficient implementation Indexing and query optimization Alternatives architectures for building

STDBMSs

fall 2000cs 599 – spatial and temporal databases research issues in spatio- temporal database...

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