Il ruolo delle “core ontologies”nel ciclo di vita del prodotto

culturale digitale

Il caso “CIDOC-CRM”

Oleg Missikoff - Prima giornata di studi sul SW Culturale – Roma, 6 luglio 2004

Life-cycle of a digital/virtual cultural resource

Identification Acquisition Description Binding Access Feedback

• Policies• Stategies• Marketing• Feedback analysis

•Digitisation•Purchase•Creation•Info atoms

•Metadata•Ontologies•Semanticannotations

• User- profiling• Story- telling• Info obj.

• Portal technology• Software agents• eLearning modules

• On-line questionn.• Polls• Forums• Interviews• Mailing list

The Three Levels of Knowledge

Entity

Object RelationLocationISA

Vase

Krater

ISA

Archive

Museum

Vaso François

Metropolitan

Intensional Level(conceptual model:types)

Extensional Level(factual model:objects)

MetaLevel(modeling ideas:metatypes)

ActivityAction

...

IDEA

instantiation

instantiation

Language Event

TimeAttribute

Class

Cratere di Vix

Archivio di Stato Louvre

Excavation

The Conceptual Layers

Upper

Domain Ontology

Core Ontology

Lower Domain Ontology

Sp

ecialization

Agg

rega

tion

The Ontology “Chestnut”

Top-down?

Or Bottom-up?

Middle-out!

CIDOC CRM

The CIDOC CRM

• The CIDOC CRM is a Conceptual Reference Model proposed by the Comité International pour la DOCumentation of the International Council of Museums

• It is an object–oriented domain ontology for the interchange of rich and heterogeneous cultural heritage information from museums, libraries and archives

• Its purpose is to provide a building block for supporting the development of a global Semantic Cultural Web

• It is maintained by the CIDOC CRM Special Interest Group, a diverse international group of museum information professionals with an official mandate from ICOM/CIDOC to develop and promote the standard.

• Work on the CIDOC CRM formally began in 1996, although it is the evolutionary descendent of CIDOC data standards initiatives going back to 1980

• The primary function of the CIDOC CRM Special Interest Group (CIDOC CRM–SIG) over the last five years has been to test and refine the CIDOC CRM in preparation for publication by ISO, the International Organization for Standardization

• The CIDOC CRM was accepted by ISO as "Committee Draft" ISO/CD 21127, and its publication as a full International Standard is due late in 2004.

The CIDOC CRM (2)

• The CIDOC CRM is comprised of a class hierarchy of 81 named classes, interlinked by 132 named properties

• Because it follows object oriented design principles, the classes in the hierarchy inherit properties from their parents, also known as superclasses

• From the various terminologies in use for object-oriented models, for ease of understanding by non-computer experts, the following have been selected :– “Entity” for anything that may be called “class”, “entity” or “node”.

– “Link” for anything that may be called “attribute”, “reference”, “link”, or “property”.

– “Superclass - Subclass” relations refer to “isA” relations, “subclass – superclass”, “ parent class - derived class”, “generalization - specialization”, etc.

The CIDOC CRM (3)

Top-level Entities relevant for Integration

participate in

E39 Actors

E55 Types

E28 Conceptual Objects

E18 Physical Stuff

E2 Temporal Entities

E41

Ap

pel

lati

ons

affect or / refer to

refer to / refine

refe

r to

/ i d

ent i f

ie

location

atwithin E53 PlacesE52 Time-Spans

A typical problem: chronology mgmt

• Information should be positioned in the appropriate time-space context

• Dates are often vaguely expressed:– Beginning of ‘800 – First half of XIX century– Between 1825 and 1830 – Circa 1827 – ...

time

before

P82 at some time within

P81 ongoing throughout

after

“in

ten

sity

”The CIDOC CRM and Time

Duration (P83,P84)

• P81: Time-Span E52 at least covering Time Primitive E61

• P82: Time-Span E52 at most within Time Primitive E61

• P83: Time-Span E52 had at least duration Dimension E54

• P84: Time-Span E52 had at most duration Dimension E54

The CIDOC CRM and Time (2)

E61 Time Primitive

Belongs to: Value TypeSubclass of: Primitive ValueScope Note: This entity is a primitive value that should implement appropriate validation and interval logic for date ranges and precision relevant to cultural documentation.

The entity is referenced by:Time-Span: at most withinTime-Span: at least covering

E52 Time-Span

Belongs to: Time TypeSubclass of: CRM EntityScope note: A determination of a range of dates or

duration without any further connotations to be used to confine periods, events, and any other phenomena valid for a certain time. A time appellation is a verbal form which refers to a time-span. The time-span itself is a temporal extent in the sense of Galilean physics. Different time-appellations may express the same time-span.

Examples: from 12-17-1993 to 12-8-1996, 14h30 – 16h22 4th July 1945, 9.30 am 1.1.1999 to 2.OO pm 1.1.1999, Duration of the Ming Dynasty.

E54 DimensionBelongs to: Measure TypeSubclass of: CRM Entity

Scope note: This entity is an abstract class for properties that are measured by some calibrated means and result in numerical values. Dimensions should be recorded according to ISO standards, or using internationally recognized non SI units whenever possible (ISO 31:1992, Quantities and units; ISO 1000:1992, SI units and recommendations for the use of their multiples and of certain other units).

Examples: currency: £26.00, length: 4 cm, diameter: 26 mm, weight: 150 lbs, density: 0.85 gm/cc, luminescence: 56 ISO lumens, tin content: 0.46 %, "taille au garrot": 5 hands, C14 date: 2460 years, etc.

Conclusions

The “core ontology” approach could provide support in the construction of new applications. In fact, usually, domain experts lack specific skills. For this reason, having an Upper Domain Ontology and as many Lower Domain Ontologies as possible could enable an “economy of scale”. It will result in a reduction of human work and, meanwhile, very useful guidelines.

Ontology building process

Domainexperts

Knowledge engineers

Discussion and agreement about contents supported by a groupware environment (HarmoConsys) Domain

Ontology

Contents representation

SymOntoX

Grazie per la vostra attenzione!