1. CoopIS, Trento, Italy, 05/09/2001
Schema design and query processing in a federated multimedia database system
Henrike Berthold & Klaus Meyer-Wegener
Dresden University of Technology, Germany
Problem
A Federated Multimedia Database System
Global schema construction
Query processing
Summary
Henrike Berthold

2. Problem Application 1 Application n SDBS 1 SDBS k MRS 1 MRS m MSS 1
MSS n
SDBS: Database system with a schema, a query language, ...
MRS: Media retrieval system
MSS: Media storage system
Henrike Berthold

3. Media retrieval systems
Perform content-based search based on automatically extracted features (perception + semantical primitives)
work for a set of media objects of a certain media type such as image, text, video, audio or a subset with a certain semantics such as passport photos
Retrieval functions
single: search argument (example, feature, weighting), media object -> similarity value
coll: search argument -> list if tuples (similarity value, MID)
result restrictions of coll: lower bound for similarity values, subset of media objects, top n
Example systems: QBIC (IBM), Excalibur Image Datablade, Melodiscov (LIP6)
Problem: only interactive interface and no programming one
Henrike Berthold

4. Media storage systems
Store and manage media objects like images, videos
provide operations for those
support especially timed playout of continuous media objects
all systems provide media description data such as size, format
some systems support transactional concepts like durability, atomicity
Example systems: Tiger Shark (IBM), Symphony (Uni Texas), Fellini (Bell Labs), Kangaroo/Memo.REAL (Dresden University of Technology)
Henrike Berthold

5. A Federated Multimedia Database System
Application 1
Application n
SDBS 1
SDBS k
MRS 1
MRS m
MSS 1
MSS n
FMDBMS
FMDBS
- Database schema and query processing
- Operations on media objects
- Transactions
Henrike Berthold

6. Global schema construction
based on two intermediate schemas:
Structured-data schema (SDS) = global schema of all SDBS-Schemas
Media schema (MS) = global schema of all MSS schemas
Structured-data Schema (SDS)
integrates
Media Schema (MS)
SDBS1-Schema
SDBSk-Schema
MSS1-Schema
MSSn-Schema
Henrike Berthold

7. Example media schema Common data model: ODMG, CROQUE
Types and subtype-relation
Classes and subclass-relation
:TSingleMedia
:TObject
Video:TVideo
Audio:TAudio
Text:TText
ContMedia:TContMedia
Image:TImage
CityPart:TImagePart
PassportPhoto:TImage
City:TImageWithPart 1 *
Henrike Berthold

8. Step 1: Base integration
Schema architecture:
MSS1-Schema
MSSn-Schema
Media Schema (MS)
SDBS1-Schema
SDBSk-Schema
Structured-data Schema (SDS)
integrates
Global Schema
Henrike Berthold

9. Step 2: Integration of media retrieval functions
single: objekt method +
coll: class method -, function -
allows combination of boolean queries with media retrieval queries
Henrike Berthold

10. Step 2: Example c2:t1 c3:t2 c1:t1 c6:t4 c7:t3 c5:t3 c4:t3 t2 t0 t1 t3
Henrike Berthold

11. Step 3: Extension Simple extension: relationships
complex extension: new objects + relationships
TVisualElement
Time interval Region
TVideoElement
TTextElement
TImageElement
TVideo
TText
TSingleMedia
TLecture
TSlide
TImage 1
1..* 2 8 x y
Region for
video
image
Region for text
t in min
Text1
Image1
Video
Image2
Text2
Henrike Berthold

12. Schema architecture Global Schema Structured-data Schema Media Schema
Internal Schema
integrates
SDBS1-Schema
SDBSk-Schema
MSS1-Schema
MSSn-Schema
MRS1-Function
MRSm-Function
Henrike Berthold

13. Construction data
Henrike Berthold

14. Query processing
Henrike Berthold

15. FMDBS-specific problems
Modification
Vertical fragmentation
GT3
GT4
GT1
GT2
complete replacement of a global object is not possible
Replacement of search methods
Henrike Berthold

16. Comprehension syntax
Henrike Berthold

17. Monads and algebras
Henrike Berthold

18. Advantages
uniform representation of collections (set, bag, list) and aggregations
readability
there are equivalences defined
easy manipulation
there is a mapping to an algebraic expression
embedding in traditional query processing is possible
thus: better suited for manipulations than an object algebra
Henrike Berthold

19. Modification
Henrike Berthold

20. Improvements
Paths that belong to one source are replaced completely; so far: replacement of each single function
A generator which binds a global object is replaced by a sequence of qualifiers which produce all local objects that are used in the query; so far: production of local objects there, where they are used
exploit function coll and its result restrictions
Henrike Berthold

21. Replacement of function single by coll
Henrike Berthold

22. Identification of a lower bound
Henrike Berthold

23. Identification of a subcollection restriction
Henrike Berthold

24. Prototype
Henrike Berthold

25. Summary
An FMDBS manages structured data and media data. It takes the integration efforts from the applications.
Development of a procedure to construct the global schema
data (relationships, new types and classes) and media retrieval functions can be added
Development of a procedure to modify queries
can handle the vertical fragmentation
choses efficiently executable media search functions
Applications have a powerful mean to find suitable data
Henrike Berthold

26. Outlook Problem: Chose a result restriction if some are applicable
Need of a general cost model of media search systems
Construction of a complete FMDBS
Need of tools which support the construction and the administration
Henrike Berthold