building ontologies from multiple information sources

Building Ontologies from Multiple Information Sources

Raji Ghawi and Nadine Cullot

Laboratoire Électronique, Informatique et Image

University of Burgundy, Dijon, France

Information Technologies (IT2009), Kaunas, Lithuania23 – 24 April 2009

Building Ontologies from Multiple Information Sources 2IT2009

Introduction

Information Integration Semantic Heterogeneity Ontologies

Content Explanation Query Formulation

Building Ontologies ?


Building Ontologies

Building Ontologies

from Scratch from Existing Sources

Costly anddifficult


Building Ontologies

Building Ontologies

from Scratch from Existing Sources

Costly anddifficult from Single

Information Sourcefrom Multiple

Information Sources


Building Ontologies from Multiple Information Sources

Possible Solutions

creatinglocal ontologies

merginglocal ontologies

mergingsource schemas

building ontologyfrom unified schema

Ontology-Merging-based Approach Schema-Merging-based Approach


Our Proposition

Ontology-Evolution-based Approach

creatinginitial ontology

involvinglocal sources

Ontology Evolution


Evolution Step

New Information Source

Ontology

Initial correspondences

MappingBridges

Expert

Automatic Treatement

Rules

OntologyChange

Operations

MappingDocument

Ontology Modification

MappingDoc 2

MappingDoc 1

MappingDoc n

Updating Previous Mappings


dp1dp2

dp1

Ontology Change Operations (Atomic)

A

B C

A

B

Add_Concept

A A

Add_DatatypeProperty

B

C

B

Add_ObjectProperty

C

opB

Set_SubConceptOf

C

B

C

is_a

Set_SubPropertyOf

op1

Set_InverseOf

op2

op1

op2

op1

op2

B C

op1

op2

B C

dp1dp2dp1

A A

Remove_Property


dpdp1dp2

dp

Ontology Change Operations (Complex)

A

B

Convert_Property

A A

Split_Property

A

B

op

dp1dp2

dpA

dp1dp2

A

Add_DatatypeProperty

Remove_Property

dp

A

B

op

A

B

op

Remove_Property

Add_ObjectProperty


Ontology Evolution by Involving a Database

Evolving Ontology Concepts Using Database Tables

Evolving Ontology Properties Using Columns


C

nothing happens

case 1 A concept C has no corresponding table



T

C

T

conceptBridge(C, T)

C


case 2 one concept C corresponds to exactly one table T


T


case 3 A table T has no corresponding concept

Case 3.1.

Case 3.2.

Case 3.3.

T1

PK1

…

T

PFK1

PFK2

T2

PK2

…

T1

PK1

…

T

PFK1

…

T

…

…


T

C

T

conceptBridge(C, T)

Add_Concept(C)


case 3.3 default case




case 3.2 T is related to T1 using a FK which is a PK


T

pfk1

D

conceptBridge(D, T1) Add_Concept(C)

Set_SubConceptOf(C, D)

T1

pk1

T

pfk1

D

T1

pk1

C

conceptBridge(C, T)



case 3.1T is used to relate T1 and T2 in many-to-many relationship


T

pfk1

pfk2

T2

pk2

T1

pk1

D1 D2

T

pfk1

pfk2

T2

pk2

T1

pk1

D1 D2op1

op2

cb1 = conceptBridge(D1, T1)

cb2 = conceptBridge(D2, T2)

Add_ObjectProperty(op1, D1, D2)

Add_ObjectProperty(op2, D2, D1)

Set_InverseOf(op1, op2)

OPB(op1, cb1, cb2, join:T.pfk1=T1.pk1 AND T.pfk2=T2.pk2)

OPB(op2, cb2, cb1, join:T.pfk1=T1.pk1 AND T.pfk2=T2.pk2)



case 4one concept C corresponds to several tables T1, T2, …, Tm

C

T1 T2

…

Tm

C1 C2 Cm

cb1 = conceptBridge(C1, T1)


...

cbm = conceptBridge(Cm, Tm)

…



case 4.1one concept C corresponds to the union of T1, T2, …, Tm


C

T1 T2

…

Tm

C1 C2 Cm

C

T1 T2

…

Tm

C1 C2 Cm



...


Set_SubConceptOf(C1, C)Set_SubConceptOf(C2, C)...Set_SubConceptOf(Cm, C)

move common properties to the super-concept C

… …



case 4.2one concept C corresponds to the join of T1, T2, …, Tm


C

T1 T2

…

Tm

C1 C2 Cm C

T1 T2

…

Tm

C1 C2 Cm



...


Set_SubConceptOf(C, C1)

Set_SubConceptOf(C, C2)

...

Set_SubConceptOf(C, Cm)

…

…



case 5one table T corresponds to several concepts C1, C2, …, Cn

C2

T

C1 CnC2

T

C1 Cn

C

conceptBridge(C, T)

Add_Concept(C)Set_SubConceptOf(C1, C)Set_SubConceptOf(C2, C)Set_SubConceptOf(Cn, C)

… …



case 6 several concepts C1, C2, …, Cn correspond to several tables T1, T2, …, Tm

C2C1 Cn…

T1 T2

…

Tm



Category 1. Correspondences between C properties and T columns.

Category 2. Correspondences between C properties and columns in other tables.

Category 3. Correspondences between T columns and properties of other concepts.

C

T

D

U

1 23

conceptBridge(C, T)



case 1A (datatype or object) property has no

corresponding column

nothing happens

T

cb = conceptBridge(C, T)

dpC

op



case 2 A column col has no corresponding property


C

T

col





C

T

col

case 2.1 col is not a foreign key

dp

DPB(dp, cb, col)

C

T

col

Add_DatatypeProperty(dp, C -> type)





cb1 = conceptBridge(D, RT)

C

T

fk

case 2.2col is a foreign key fk referring to a column rc in

another table RT

D

RT

rc

C

T

fk

D

RT

rc

op

OPB(op, cb, cb1, join: T.fk = RT.rc)

Add_ObjectProperty(op, C -> D)


dp


case 3A datatype property dp corresponds directly to one

column col


C

T

col

dp

DPB(dp, cb, col)

C

T

col



case 4An object property op corresponds directly to a

foreign key fk


C

T

fk

D

RT

rc

op




foreign key fk

C

T

fk

D

RT

rc

op

RT is mapped to the concept Dcase 4.1

C

T

fk

D

RT

rc

op


cb1 = conceptBridge(D, RT)OPB(op, cb, cb1, join: T.fk = RT.rc)




foreign key fk

C

T

fk

D

RT

rc

op

RT is mapped to a concept F different from Dcase 4.2

C

T

fk

D

RT

rc

op


cb1 = conceptBridge(F, RT)

F D

Set_SubConceptOf(F, D)Add_ObjectProperty(op’, C -> F)Set_SubPropertyOf(op’, op)

F Fop'

OPB(op’, cb, cb1, join: T.fk = RT.rc)


dp


case 5 A datatype property dp corresponds to a transformation of one column col


C

T

col

dp

DPB(dp, cb, Trans(col))

C

T

col

Trans Trans


dp


case 6


C

T

col1

col2

Trans

A datatype property dp corresponds to a transformation/combinationof multiple columns col1, col2, …, colm


dp


case 6


C

T

col1

col2

dp

DPB(dp, cb, Trans(col1, col2))

C

T

col1

col2

Trans Trans


First solution


dp


case 6


C

T

col1

col2

T

col1

col2

Trans


Second solution

DPB(dp1, cb, col1)DPB(dp2, cb, col2)

Split_Property(dp AS dp1 = Trans1(dp), dp2 = Trans2(dp))

dp1Cdp2


dp1


case 7


C

T

col

T

col

A column col corresponds to a combination/transformation of multiple datatype properties dp1, dp2, …, dpn

DPB(dp1, cb, Trans1(col))DPB(dp2, cb, Trans2(col))

dp2

Trans

dp1Cdp2

Trans1

Trans2


Conclusions & Future Works

Ontology-Evolution based Approach Semi-Automatic Process Non-exhaustive list of correspondence

cases

Conditional Mappings Implementation

Thank You.

Questions ?

building ontologies from multiple information sources

Technology