mfi ontology registration ed2 ~toward ontology evolution management ~ okabe, masao co-editor iso/iec...

MFI Ontology registration Ed2 ~Toward ontology evolution management ~

OKABE, Masao

Co-editor

ISO/IEC 19763-3 MFI Ontology registration project

2007.12.07

目的外使用・複製禁止 2

Outline

1. What is MFI Ontology registration Ed1?

2. What lacks in MFI Ontology registration Ed1?

3. Evolution management in MFI Ontology registration Ed2

4. Other topics in MFI Ontology registration ED2

5. Overview of proposed Ed2 metamodel

2007/12/07 東京電力・システム企画部・岡部雅夫





4. Other topics in MFI Ontology registration Ed2



目的外使用・複製禁止

What is MFI Ontology registration Ed1?

ISO/IEC 19763-3 MFI Ontology registration Ed1is a part of the Metamodel Framework Interoperability standards,

andwas published as a IS on March 1st, 2007.

Metamodel Framework Interoperability projectis multi-part project intending to promote interoperability of

metamodels, models and ontologies etc. Part 1 Reference model IS Part 2 Core model FCD Part 3 Metamodel for ontology registration IS, WD of Ed2 in preparation Part 4 Metamodel for model mapping CD Part 5 Metamodel for process models registration WD in preparation Part 6 Registration procedure Study Period

Participating Counties: Canada, China, Japan, Korea, UK, U.S.Main contributors: China, Japan, Korea



Features of MFI Ontology registration

FeaturesVery simple specifications as a first step

Think big, act samll!

Simple and generic structure, irrelevant to languages–Ontology_Whole － Ontology_Component － Ontology_Atomic_Construct

Providing a framework to ensure trustiness Reference Ontology vs. Local Ontology

Using a MFI Ontology registration registry, we can at least know what ontologies are there and whether they are trusty or not and get a clue to reuse them.

Since it is very simple and generic, MFI Ontology registration only has a little semantics of ontologies, and for their full semantics, it relies on repositories such as OMG ODM.



Simple and generic structure (1 of 4):Common basic structure of ontologyAlmost any ontology has this simple three granularity structure.

An ontology consists of sentences.

e.g. Example_Ontology consists of Buyer has.Creditrating(Tony) Buyer(Tony) Creditrating(Credit-A)

A sentence uses symbols.e.g. Buyer has.Creditrating(Tony) uses Buyer has logical symbols , , (and variables )

Creditrating Tony

Ontology

Sentence

Symbol



Simple and generic structure (2 of 3):MFI Ontology registration structure

MFI Ontology registration consists of

Ontology Whole, Ontology Component, Ontology Atomic Construct

that correspond to ontology, sentence, symbol * respectively

and that haveadministrative information ** of its correspondentstructural information of this levela reference(URI) to its correspondent,

for further semantics, if necessary

Note* : Logical symbols such as , , and variables are ignored.

**: inherited from Administered Item of ISO/IEC 11179-3 MDR ,

such as registration authority, creation date etc.



Simple and generic structure (3 of 3):MFI Ontology registration structure

e.g.

Administrative information etc.

corresponding to Example_Ontology

e.g.


corresponding to each of Buyer has.Creditrating(Tony) Buyer(Tony) Creditrating(Credit-A)

e.g.


corresponding to of each Buyer has

Creditrating Tony

Ontology Whole +administrative info.

Ontology Component +administrative info

Ontology Atomic Construct +administrative info

MFI Ontology registrationActual ontology

Ontology

Sentence

Symbol

reference

consistOf

use

reference

reference

For actual ontologies, MFI Ontology registration mainly relies on OMG ODM



Providing a framework to ensure trustinessReference Ontology vs. Local Ontology

Reference OntologyStandardized ontology

that is usable and sharable by a community of interestTrustworthy to others

A reference ontology consists of sentences only in reference ontologies.A sentence in a reference ontology uses symbols only in reference ontologies.

Local OntologyLocalized ontology

for some applications based on Reference Ontologies It is its user’s responsibility to trust this ontology or not.

A local ontology consists of sentences both in this local ontology and other reference ontologies.

A sentence in a local ontology uses a symbols in this local ontology and other reference ontologies.



Core portion of MFI Ontology registration metamodel

Reference Ontology Whole

Reference Ontology Component

Reference Ontology Atomic Construct

Local Ontology Whole

0:*0:1Local Ontology Component

Local Ontology Atomic Construct0:1 0:*

sameAs

sameAs



Example1 (1 of 2)Suppose that ontology A consists of sentence RC1, RC2 and

RC3 as follows;

11

RC1

<owl:ObjectProperty rdf:ID="dimensionality"><rdfs:domain rdf:resource="#Unit" /><rdfs:range rdf:resource="#Dimensionality" /></owl:ObjectProperty>

<owl:Class rdf:ID="KernelUnit"><rdfs:subClassOf rdf:resource="#Unit"/></owl:Class>

<KernelUnit rdf:ID="metre"><dimensionality><Dimensionality rdf:ID="length"/></dimensionality></KernelUnit>

RC2

RC3



Example1 (2 of 2)

NoteOWL constructs such as “ObjectProperty”, “subClassOf” etc. have no effects.

12

A URI Administered Info.

RC1 NamespaceURI Administered Info.



KernelUnit NamespaceURI Administered Info.

dimensionality NamespaceURI Administered Info.

Dimensionality NamespaceURI Administered Info.

Unit NamespaceURI Administered Info.

metre NamespaceURI Administered Info.

length NamespaceURI Administered Info.

Ontology Whole

Ontology Component

Ontology Atomic Construct

Metadata registered in MFI Ontology registration



Nature of ontologies

By nature,

ontologies are reused mutually and

ontologies evolve gradually

as they capture more semantics.



Example2First, ontology B uses ontology A.

Second, ontology A evolves from ver.1 to ver.2.But ontology B still uses ontology A ver.1.

Third, ontology C uses ontology A ver.2.

Note:This kind of situation often happens.

ontology B ontology A use

ontology Buse ontology A

Ver.2Ver.1evolves


Ver.2Ver.1evolves

ontology Cuse



Problem of MFI Ontology registration Ed1

MFI Ontology registration needs to support facilities

to manage multi-versions of an ontology and

to manage how an ontology evolves.

However, MFI Ontology registration Ed1 does not have such facilities.



Example1 (1 of 4) :roughly speakingSuppose that ontology A evolves as follows;

17

RC2

<owl:Class rdf:ID="KernelUnit"><owl:disjointWith rdf:resource="#Unit/> </owl:Class>

RC1

<owl:ObjectProperty rdf:ID="dimensionality"><rdfs:domain rdf:resource="#Unit" /><rdfs:range rdf:resource="#Dimensionality" /></owl:ObjectProperty>

RC2

<owl:Class rdf:ID="KernelUnit"><rdfs:subClassOf rdf:resource="#Unit"/></owl:Class>

RC3

<KernelUnit rdf:ID="metre"><dimensionality><Dimensionality rdf:ID="length"/></dimensionality></KernelUnit>

evolves

Note: “subClassOf “and “disjointWith” are very different semantically.



Example1 (2 of 4) :roughly speakingAlthough RC2 evolves substantially, there is no change in MFI Ontology registration Ed1 except (Namespace)URI and some Adminitered Information

since “subClassOf” and “disjointWith” have no effect to MFI Ontology registration.

18

A URI Administered Info.




KernelUnit NamespaceURI Administered Info.

dimensionality NamespaceURI Administered Info.

Dimensionality NamespaceURI Administered Info.

Unit NamespaceURI Administered Info.

metre NamespaceURI Administered Info.

length NamespaceURI Administered Info.

Ontology Whole

Ontology Component




Example1 (3 of 4): more precisely speaking

Fortunately or unfortunately, usually, different versions of an ontology are identified by different URIs.

For example, The current version of famous OWL Wine ontology is identified by

http://www.w3. org /TR/2003/PR-owl-guide-20031209/wine, which is also xmlns and xml:base. The prior version is identified by http://www.w3.org/TR/2003/CR-owl-guide-20030818/wine, which is also

xmlns and xml:base. So, in the current version, “wine” is http://www.w3.org/TR/2003/PR-owl-guide-20031209/wine#wine but, in

the prior version, it is http://www.w3.org/TR/2003/CR-owl-guide-20030818/wine#wine and they are different.

Then, in MFI Ontology registration registry,

every component and atomic constructs of the current version and of the prior version are regarded as different

since they are identified by NamespaceURI-prefixed name.



Example1 (4 of 4) : more precisely speakingIn MFI Ontology registration, ontology A ver.1 and ontology A ver.2 are treated as comletely different since their

(Namespace)URIs are different, although they are practically same except RC2 are substantially different.

20

A URI _1 Admin. Info.

RC1 NsURI_1 Admin. Info.



KernelUnit NsURI_1 Admin. Info.

dimensionality

NsURI_1 Admin. Info.

Dimensionality


Unit NsURI_1 Admin. Info.

metre NsURI_1 Admin. Info.

length NsURI_1 Admin. Info.







dimensionality


Dimensionality




<ver. 1> <ver. 2>completely different



Example2

In the case that ontology B uses ontology A ver.1 and that ontology C uses ontology A ver.2

What MFI Ontology registration can recognize is

In MFI Ontology registration Ed1, the fact that “ontology B uses ontology A ver.1” is represented as “an ontology_whole of ontology B consists of ontology_components of ontology A ver.1”.

But, ontology A ver.1 and ontology A ver.2 are different ontologies and not different versions of the same ontology.

and not


ver.2ver.1evolves

ontology Cuse

ontology Buse

ontology A ver.1 ontology Cuse

ontology A ver.2






4. Other topics in MFI Ontology registration




What is MFI Ontology registration Ed2?

MFI Ontology registration Ed2 supports facilities

to manage multi-versions of an ontology and

to manage how an ontology evolves,

since ontologies are reused mutually and

ontologies evolve gradually as they capture more semantics

by nature.



Overview: example1

24






dimensionality


Dimensionality











dimensionality


Dimensionality




<ver. 1> <ver. 2>evolves

same

corresponds to

evolves from ver.1 to ver.2Some other metadata such as backward compatibility etc.

same



Three cases

There are three cases that an ontology evolves outside MFI Ontology registration registry.

Case1 Different URIs for each version of an ontology and

different URIs for each version of names in an otology

Case2 Different URIs for each version of an ontology, but mostly

the same URIs for each version of names in an ontology This is a typical case.

Case3 Same URI for each version of an ontology. Usually, this is the case that Persistent URLs are used.

e.g. http://purl.org/dc/elements/1.1/

Since MFI Ontology registration is so generic, it should support all of them.



Case1 (1 of 2)

Different URIs for each version of an ontology and

different URIs for each version of symbols in an otologyThis is the case shown as the example1 in Overview (at slide 24)

etc.

It is not easy to decide whether the corresponding symbols have the same semantics or not.



Case1 (2 of 2)

For example, concerning “KernelUnit” Probably, many people say “KernelUnit in ver.1 and in ver.2 have different semantics because

in ver.1, KernelUnit is a subclass of Unit but in ver.2, KernelUnit is disjoint with Unit.

Then, how about Unit? Some people may say “Unit in ver.1 and in ver2 have different semantics because in ver.1 Unit

has KernelUnit as a subclass, but not in ver.2”. But, others may say “No. That difference is not about Unit but about KernelUnit .”

How about metre? Some people may say “Metre in ver.1 and in ver.2 have different semantics because in ver.1,

metre is an instance of Unit, but not in ver. 2”. But, probably many say “No. They are the same”



Case 2 (1 of 2)

Different URIs for each version of an ontology, but mostly

the same URIs for each version of names in an ontologySee example3 at next slide.

In this case, Unit, KernelUnit and metre are identical in ver.1 and ver.2 as symbols since they have the same NsURI_1 both in ver.1 and ver.2.

However, it is still not easy to decide whether they have the same semantics in ver.1 and ver.2.



Case2 (2 of 2): example 3

29






dimensionality


Dimensionality









<ver. 1> <ver. 2>evolves

evolves from ver.1 to ver.2Some other metadata such as backward compatibility etc.

same same



Case3

Same URI for each version of an ontologyThis is a case that an ontology is just updated and mulch-versions

cannot be supported.

MFI Ontology registration can at least update the administered information such as “version”, “effective date” etc.



Issues to be resolved

Whether fork-type evolution is acceptable or not?Maybe, for local ontologies, yes, but

for reference ontologies, no, since

reference ontologies should be standardized.

Whether a new version may have

the same URI as its prior version? If always only the latest version is necessary, it is fine.

Actually, Persistent URLs are very convenient.

But, if multi-versions are necessary, it is not advisable (i.e. Case 3).

Exact metadata (references and attributes) that MFI Ontology registration metamodel shall have.

China is extensively studying them.

31

ver.1

ver.2 ver.3

ver.4 ver.5

fork-type evolution



1) Relation between reference and local ontology will be expanded.

Motivation (1 of 2)

The relation between reference ontology and local ontology in MFI Ontology registration Ed1 needs to be expanded to a partial-ordered relation.

MFI Ontology registration Ed1 defines Reference Ontology and Local Ontology as follows;

Reference Ontology

–ontology that is usable and sharable by a community of interest Local Ontology

–ontology that is specialized for defined applications and based on at least one reference ontology

puts the following constraints on local ontology. A local_ontology_component shall be consisted of by exactly one local_ontology_whole and not by a

reference_ontology_whole since it is localized. A local_ontology_atomic_construct shall be used by exactly one local_ontology_component and not by a

reference_ontology_component since it is localized.



1) Relation between reference and local ontology will be expanded.

Motivation (2 of 2)

By nature, however, ontologies are reused mutually.

Even local ontologies should be able to reused by other local ontologies in some extent.

MFI Ontology registration Ed2 will introduce a partial order relation among local ontologies to control the extent that local ontologies can be reused by other local ontologies.



A partial ordered set “Reusable Level”

MFI Ontology registration Ed2 will introduce a partial ordered set called “Reusable Level”.There is an element R“Reusable Level”For any element e “Reusable Level”, e R

Example

35

R

L1 L2

L5L4

L3

1) Relation between reference and local ontology will be expanded



A reference “reusability”

Ontology Whole, Ontology Component and Ontology Atomic Construct will have a reference called “reusability” to “Reusable Level” with its multiplicity 1:1.

Ontolgy Whole O has R as reusability

iff O is a reference ontology.

Ontology Component C has R as reusability

iff C is a reference ontology component.

Ontology Atomic Construct A has R as reusability

iff A is a reference ontology atomic construct.

36




Extended constraints for reusability

Extended constraints in ED2A local_ontology_component with reusability Ln can be consisted of

by an ontology_whole with reusability Lm

iff Lm Ln.A local_ontology_atomic_construct with reusability Ln can be used

by a local_ontology_component with reusability Lm

iff Lm Ln.

Note:This is a natural extension of the following constraints in Ed1.

A local_ontology_component shall be consisted of by exactly one local_ontology_whole and not by a reference_ontology_whole .

A local_ontology_atomic_construct shall be used by exactly one local_ontology_component and not by a reference_ontology_component.

37




ExampleA reference ontology component can be reused by any ontology

component since reference ontology component has maximum reusability R.

38

L3

R

L1 L2

L5L4

A local ontology

atomic construct

with reusability L1

can be reused by

a local ontology

component with

reusability L1, L3 or L4

and not with R, L2 or L5.

A local ontology

atomic construct

with reusability L2

can be reused by

a local ontology

component with

reusability L2, L3, L4 or L5

and not with R or L1.




2) Ed2 will support ontology inclusion. (1 of 2)Ed1 does not support ontology inclusion such as “owl:import”.So, in the case of

Ed1 simply registers ontology A as follows, expanding “import”.

2007/12/07 東京電力・システム企画部・岡部雅夫 39

A

C-A1 C-A2

A-A1 A-A2 A-A3

B

C-B1 C-B2

A-B1 A-B2

importsontology

sentence

symbol

ontology whole

ontology component

ontology atomic construct

A

C-A1 C-A2

A-A1 A-A2 A-A3

C-B1 C-B2

A-B1 A-B2


2) Ed2 will support ontology inclusion. (2 of 2)

But, Ed1 has a problem in the case that ontology B is not registered because in that case ontology A cannot expand ontology B.

So, Ed2 will simply register ontology A as it is as follows,

Note:

Since ontology B is not registered, the information on the ontology component and ontology atomic construct of ontology B cannot be gained, but a part of the information on the ontology whole of ontology B can be gained from ontology A.

ontology whole

ontology component

ontology atomic construct

A

C-A1 C-A2

A-A1 A-A2 A-A3

B imports


3) Ed2 will use IRIs, rather than URIs.

To support non-European characters, including Hungul, Chinese and Japanese character,

MFI Ontology registration Ed2 will use IRIs, rather than URIs.

IRI : RFC 3987 Internationalized Resource Identifiers (IRIs),

IETF Proposed Standard



Overview of proposed Ed2 metamodel

Evolution and reusability view

only if reusability of an ontology component is lessThanOrEqual to reusability of an ontology atomic construct.


Ontology Whole

Ontology Component


sameAs

sameAs

evolvesTo

evolvesTo

correspondsTo

only if reusability of an ontology whole is lessThanOrEqual to reusability of an ontology component.

reusability

reusability

lessThanOrEqual

Reusable Level

imports


Overview of proposed Ed2 metamodel

Reference and Local Ontology view

only if 　 reusability of an ontology component　　　　　 is lessThanOrEqual to reusability of 　　　　　 an ontology atomic construct.

0:*0:1

0:1 0:*

sameAs

sameAs

only if reusability of an ontology whole 　　　　　　　 is lessThanOrEqual to reusability of 　　　　　 an ontology component.

evolvesTo

correspondsTo

0:1

0:*

0:*

0:1

evolvesTo0:1

0:*

evolvesTo

evolvesTo

correspondsTo evolvesTo0:1

evolvesTo

0:10:1

0:1

evolvesTo0:1 0:1

0:1

0:1

0:1

0:1

0:1

0:1

Local OntologyWhole

Local OntologyComponent

Local OntologyAtomic Construct

Reference OntologyAtomic Construct

Reference OntologyComponent

Reference OntologyWhole


Note: The associations “imports” are omitted just for simplicity


Thank you for your attention.MFI Ontology registration Ed2 WD is in preparation.Any comments and/or contributions are very welcome to

okabe.masao<at>tepco.co.jp.


mfi ontology registration ed2 ~toward ontology evolution management ~ okabe, masao co-editor iso/iec...

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