Local tableaux for reasoning in distributed description logics a - - PowerPoint PPT Presentation

local tableaux for reasoning in
SMART_READER_LITE
LIVE PREVIEW

Local tableaux for reasoning in distributed description logics a - - PowerPoint PPT Presentation

DDL reasoning L. Serafini & A. Tamilinr Local tableaux for reasoning in distributed description logics a Luciano Serafini 1 and Andrei Tamilin 2 1 IRST, Trento, Italy 2 University of Trento, Italy DL workshop 2004 a Alex Borgida, and


slide-1
SLIDE 1

DDL reasoning

  • L. Serafini & A. Tamilinr

Local tableaux for reasoning in distributed description logicsa

Luciano Serafini1 and Andrei Tamilin2

1IRST, Trento, Italy 2University of Trento, Italy

DL workshop 2004

aAlex Borgida, and PELLET’s Team

DL 2004 – June 8, 2004 1

slide-2
SLIDE 2

DDL reasoning

  • L. Serafini & A. Tamilinr

Talk Overview

  • 1. Motivations
  • 2. Distributed description logics (DDL)
  • 3. Basic logical properties
  • 4. Checking subsuption in DDL
  • 5. Conclusion

DL 2004 – June 8, 2004 2

slide-3
SLIDE 3

DDL reasoning

  • L. Serafini & A. Tamilinr

Motivation

GOAL Support Distributed Reason- ing in a web of ontologies REQUIREMENTS

  • 1. minimal changes on the on-

tologies

  • 2. Reuse previous theory and

tools

  • 3. Deal with heterogenaous on-

tologies

DL 2004 – June 8, 2004 3

slide-4
SLIDE 4

DDL reasoning

  • L. Serafini & A. Tamilinr

Example

Temporarily enrich Word-Net plain list of jobs with the ISCO-88 standard classification for professions.

ISCO-88 Wordnet 2 Professionals 21 Physical, mathematical and engineering science profess. 211 Physicists, chemists and related professionals . . . 214 Architects, engineers and related professionals 2141 Architects, town and traffic planners 2146 Chemical engineers 3 Technicians and associate professionals 31 Physical and engineering science associate professionals 311 Physical and engineering science technicians 3111 Chemical and physical science technicians 3112 Civil engineering technicians 312 Computer associate professionals adEntity Causal agency Cause Causal agent . . . Person Self Nurser Engineer Capitalist Worker Captor Commoner

DL 2004 – June 8, 2004 4

slide-5
SLIDE 5

DDL reasoning

  • L. Serafini & A. Tamilinr

Proposed Solution

  • 1. Discover mappings between ISCO-OO, and (subpart of) WorNet
  • 2. Represent ISCO-88, Word-Net, and Mappings in a logical formalism;
  • 3. Define and implement a suitable decision procedure

DL 2004 – June 8, 2004 5

slide-6
SLIDE 6

DDL reasoning

  • L. Serafini & A. Tamilinr

Proposed Solution

  • 1. Discover mappings between ISCO-OO, and (subpart of) WorNet

Use some (semi)automatic matching procedure (not our foucs here)

  • 2. Represent ISCO-88, Word-Net, and Mappings in a logical formalism;

Distributed Description Logics (DDL)

  • 3. Define and implement a suitable decision procedure

Distributed Tableaux Reasoning in DDL

DL 2004 – June 8, 2004 6

slide-7
SLIDE 7

DDL reasoning

  • L. Serafini & A. Tamilinr

DDL: Syntax

Given a set I of indexes.

  • A DDL is a family of description logics DL i one for each i.
  • A Bridge Rule from i to j, in a DDL is an expression of the following forms:

i : x

j : y

(into bridge rules)

i : x

✄ ✁ ✂

j : y

(onto bridge rules) where x and y are concepts/role/individuals of DL i and DL j.

  • a Distributed T-box is a pair
☎ ✆

Ti

i

I

✟✡✠ ☛

where

– Ti is a T-box of DLi; –

is a set of bridge rules in DDL

DL 2004 – June 8, 2004 7

slide-8
SLIDE 8

DDL reasoning

  • L. Serafini & A. Tamilinr

Bridge Rules: Example - 1/2

ISCO : Professionals

WNP : Worker ISCO : Architects Engineers and Relate Profess.

✄ ✁ ✂

WNP : Engineer

DL 2004 – June 8, 2004 8

slide-9
SLIDE 9

DDL reasoning

  • L. Serafini & A. Tamilinr

Bridge Rules: Example - 2/2

ISCO :

WNP :

Child

ISCO : Doorkeepers watchpersons and. . .

✄ ✁ ✂

WNP : Gatekeeper

DL 2004 – June 8, 2004 9

slide-10
SLIDE 10

DDL reasoning

  • L. Serafini & A. Tamilinr

DDL: Semantics

A distributed interpretation for a distributed T-box

  • is a pair
✁✄✂ ☎ ✆

I i

i

I

✟ ✆

rij

i

✆✞✝

j

I

consisting of

  • a local interpretation I i for DLi over domain ∆I i, and
  • a domain relation from i to j, for each i

j

I i.e., a binary relation rij

∆I i

∆I j.

DL 2004 – June 8, 2004 10

slide-11
SLIDE 11

DDL reasoning

  • L. Serafini & A. Tamilinr

Local interpretation

We have to give a distributed interpretation of a set of T-boxes, where some of them are

  • inconsistent. (Consistent, Inonsistent)

Distributed T-Bos

T1

T2

T3

T4

T5

Distributed interpretation

I 1

I 2

I 3

I 4

I 5

I 2

I 4

I 5 are interpretations of T2

T4

T5, respectively I 1 and I 3 are Paritally inconsistent local interpretation is an interpretation where

  • can

be interpreted in a non empty set.

DL 2004 – June 8, 2004 11

slide-12
SLIDE 12

DDL reasoning

  • L. Serafini & A. Tamilinr

Bridge rules: Satisfi ability (into)

d i : A

j : G,

if

rij

AI i

✂ ✡

GI j;

r

12

r

12(A)

A dom1 dom 2 G DL 2004 – June 8, 2004 12

slide-13
SLIDE 13

DDL reasoning

  • L. Serafini & A. Tamilinr

Bridge rules: Satisfi ability (onto)

d i : B

✄ ✁ ✂

j : H,

if

rij

BI i

  • HI j;

r

12

r

12(B)

dom1 dom 2 B H DL 2004 – June 8, 2004 13

slide-14
SLIDE 14

DDL reasoning

  • L. Serafini & A. Tamilinr

DDL: Subsumption propagation

Isa Isa Worker Engineer Professionalse ISCO 88 WordNet

Architects_Engineers_ and related professional

ISCO : Professionals

WNP : Worker ISCO : Architects Engineers and Relate Profess.

✄ ✁ ✂

WNP : Engineer

DL 2004 – June 8, 2004 14

slide-15
SLIDE 15

DDL reasoning

  • L. Serafini & A. Tamilinr

Reasoning in DDL

DL 2004 – June 8, 2004 15

slide-16
SLIDE 16

DDL reasoning

  • L. Serafini & A. Tamilinr

Generalized Subsumption propoagation

T1

A

  • B1
✁ ✂ ✂ ✂ ✁

Bn, (Local Subsumption) 1 : A

✄ ✁ ✂

2 : G 1 : B1

2 : H1

. . .

1 : Bn

2 : Hn

✄ ☎ ☎ ☎ ☎ ☎ ☎ ✆ ☎ ☎ ☎ ☎ ☎ ☎ ✝

(Bridge rules in

12)

  • 12

d 2 : G

  • 2 : H1
✁ ✂ ✂ ✂ ✁

Bn

DL 2004 – June 8, 2004 16

slide-17
SLIDE 17

DDL reasoning

  • L. Serafini & A. Tamilinr

Completeness of Generalized Subsumption propoagation

  • 12
✂ ☎

T1

T2

✟✡✠

12

be a distributed T-box,

  • 12

X

  • Y : 2

T2

✂ ✠

12

T1

X

  • Y

DL 2004 – June 8, 2004 17

slide-18
SLIDE 18

DDL reasoning

  • L. Serafini & A. Tamilinr

Checking subsumption itn

12

We propose a tableaux based distributed algorithm, build on top of local reasoner for each

DLi.

Tabi

Φ

computes a finite representation of a DLi-tableaux for Φ in Ti

DL 2004 – June 8, 2004 18

slide-19
SLIDE 19

DDL reasoning

  • L. Serafini & A. Tamilinr

dTab j

  • Φ

1: T=Tab j

  • Φ

;

perform local reasoning and create completion tree

2: if (T is not clashed) then 3:

for each open branch β in T and each node x of β do

4: A

☎ ✆

A

i : A

✞ ✟ ✠

j : G

G

L

  • x
✁ ☞

;

5: B

☎ ✆

B

i : B

✌ ✟ ✠

j : H

✡ ✍

H

L

  • x
✁ ☞

;

6:

if A

✎ ☎

/ 0 and B

✎ ☎

/ 0 then 7:

for each A

A do 8:

if (dTabi

  • A
✏ ✍ ✑

B

is not satisfiable) then

9:

close β;

clash in x

10:

break;

verify next branch

11:

end if

12:

end for

All bridge rules involving x are applied

13:

end if

14:

end for

all branches are verified

15: end if 16: if (T is clashed) then 17:

return unsatisfiable;

18: else 19:

return satisfiable;

20: end if 21: END

T1

✒✔✓

A

B1

✖ ✗ ✗ ✗ ✖

Bn, 1 : A

✘ ✙ ✚

2 : G 1 : B1

✛ ✙ ✚

2 : H1

. . .

1 : Bn

✛ ✙ ✚

2 : Hn

12

✒✔✓

d 2 : G

2 : H1

✖ ✗ ✗ ✗ ✖

Bn

DL 2004 – June 8, 2004 19

slide-20
SLIDE 20

DDL reasoning

  • L. Serafini & A. Tamilinr

Implementation

manager Peer ontology manager Peer ontology Peer ontology manager

  • Peer-to-peer architecture (communication based on standard HTTP based

communication)

  • Ontology manager based on PROTEGE
  • Local reasoner Tabi based on PELLET

DL 2004 – June 8, 2004 20

slide-21
SLIDE 21

DDL reasoning

  • L. Serafini & A. Tamilinr

DL 2004 – June 8, 2004 21

slide-22
SLIDE 22

DDL reasoning

  • L. Serafini & A. Tamilinr

DL 2004 – June 8, 2004 22

slide-23
SLIDE 23

DDL reasoning

  • L. Serafini & A. Tamilinr

Related work

ε-connection DDL is a special case of ε-connection. Some difference in the representation

  • f local inconistency

Logic of context DDL is clearly related with both Mc Carthy’s and Giunchiglia’s logics of

contexts

DL for information integration Catarci & Lenzerini CIS. C-OWL language proposal DDL provide a formal semantics and reasoning support for for

C-OWL.

DL 2004 – June 8, 2004 23

slide-24
SLIDE 24

DDL reasoning

  • L. Serafini & A. Tamilinr

Conclusion

  • DDL formal semantics for distributed partially inconsistent and Heterogeneous
  • ntologies
  • Theoretical characterization of subsumption in DDL with atomic bridge rules
  • Sound and complete algorithm computing subsumption in DDL
  • Prototype implementation based on PELLET

DL 2004 – June 8, 2004 24

slide-25
SLIDE 25

DDL reasoning

  • L. Serafini & A. Tamilinr

GRAZIE!

DL 2004 – June 8, 2004 25