Knowledge Content Objects: a grounded ontology for
content management over the semantic web
Aldo Gangemi
Laboratory for Applied Ontology
Istitute of Cognitive Sciences and Technology
CNR, Rome
[email protected]
Ontology application: the state of play
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Ontologies used for any purpose, from domain to task to
application (service) modelling
Ontology building easier when limited to small communities for
small tasks in simple applications, and as a controlled terminology
(cf. FOAF)
Real world applications are more difficult: medium to large
organizations and communities, complex tasks (otherwise why
bothering?), not only controlled terminologies, distributed and
networked communities, need to manage inconsistency, conflicts,
evolution, provenance, severe integration problems
Ontologies for humanities pose specific problems, due to typical
problem solving (or problem dropping) procedures --- interpretation
being a major challenge
Just like in human cognition, we need patterns emerging out of
complexity
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Related projects
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DOLCE and its extensions: http://dolce.semanticweb.org
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OntoWordNet: http://www.w3.org/2001/sw/BestPractices/WNET
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Migration of WordNet to formal ontology
Metokis: http://metokis.salzburgresearch.at
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Reusable reference ontologies, in various logical languages
CIDOC2DOLCE: alignment and extension of CIDOC, ask me
6th FP project, just finished, see this presentation
W3C Semantic Web Best Practices and Deployment Working
Group: http://www.w3.org/2001/sw/BestPractices/
CODePs: see my ISWC2005 paper: Ontology Design Patterns for
Semantic Web Content, web page with a repository asap
NeOn: http://www.neon-project.org
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6th FP IP project: networked, collaborative ontologies, starts in March
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
How Metokis fits in the OE state of play
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Application and content modelling are getting closer
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Abstraction step: going “outside the computational box”
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Ontology patterns used in conceptual modelling
Case tools used in ontology engineering
KOS being reengineered or at least ported to semantic models
Social tasks and knowledge: support for knowledge collectives
Computational tasks should become a(n executable) part of a social
process of knowledge elicitation, negotiation, and sharing
Metokis ontologies are an attempt to fill the modelling gap between
social and computational tasks and knowledge
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Plan Ontology
IO and KCO Ontology
Ontology Design Patterns
Everything based on the DOLCE foundational layer
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Modelli di progettazione ontologica
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Design pattern:, esempi di risoluzione di problemi generati da
analisi dei requisiti
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In architettura (Alexander): modelli di progettazione da “buoni esempi”
Nel software engineering (Gamma et al.): componenti software
sperimentati
In ingegneria ontologia?
Content Ontology Design Pattern: modelli concettuali, esempi di
risoluzione di problemi generati da analisi dei requisiti
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CODeP logici: soluzioni a partire da vincoli logici
CODeP concettuali: frammenti di ontologie, ricchi di relazioni e
costruitii per soddisfare le necessità degli esperti/utenti di un dominio
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Modularità: Stratificazione dei moduli
Foundational ontology (domain-independent)
{Object, Process, Part, Time, Location, Representation, Plan, …}
Inherits from
Core ontology (specific domain-independent)
{Work of art, Painting technique, Author, Artistic period, Plastic art, Interpretation, …}
Inherits from
Domain ontology
{Sculpture,Restoration, Mythical being, Caryatid, Doric order, Armilla, Fresco, …}
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Criteri di costruzione: Sfingi
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Quante (e quali) sfingi?
class
Greek mythical creature
individual
word
“sphinx”
instance-of
statue
lexicalizes
lexicalizes
sphinx
lexicalizes
Sphinx
metaphorical
blending
lexicalizes
sphinx
instance-of
English
expressed_
according_to
lexicalizes
Sphinx
The Sphinx
interpersonal role
instance-of
represents
refers_to
“Oedipus and the Sphinx”
Aegyptian mythical creature
instance-of
lexicalizes
sphinx
*refers_to
represented_by
subclass-of
instance-of
metaphorical
blending
symbolic figure
pharaoh
plays_role
plays_role
monument
stoney object
to be restored
* in naïve iconography
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Quali modelli di progettazione ho usato?
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Classe  Individuo, istanza_di(individuo, classe)
Parola Entità, lessicalizza(parola, entità)
Oggetto informativo Individuo, rappresenta(oggetto informativo, individuo)
Oggetto informativo Concettualizzazione, esprime(Oggetto informativo,
concettualizzazione)
Oggetto Ruolo, gioca(oggetto, ruolo)
Individuo@spazio1 Individuo@spazio2,
fusione_metaforica(individuo@spazio1, individuo@spazio2)
!!! Informalmente parlando … in realtà rappresentati in linguaggi logici
computabili (KIF, OWL(DL), CL, etc.)
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Cosa ci faccio?
Ex: query su dati semistrutturati (ex. documenti in un Semantic Web)
«tell me what works of art from ancient Egypt are related to European
works of art that also involve Greek mythology in a same cultural
unit»
(retrieve (?x1 ?x2)
(exists (?y ?z ?k)
(and
(creation_3 ?x1) (creation_3 ?x2)
(non-physical-object ?y)
(or (and (represents ?x1 ?y)
(origin ?y Classical_Greece))
(exists ?w
(and (non-physical-object ?w)
(represents ?x1 ?w)
(refers-to ?w ?y)
(origin ?w Classical_Greece))))
(or (and (represents ?x2 ?y)
(origin ?y Classical_Greece))
(exists ?w1
(and (non-physical-object ?w1)
(represents ?x2 ?w1)
(refers-to ?w1 ?y)
(origin ?w1 Classical_Greece))))
(origin ?x1 EGYPTIAN_EMPIRE$EGYPT)
(origin ?x2 EUROPE))))
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Altri modelli
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Oggetto informativo  Oggetto fisico, realizzato_da(oggetto
informativo, oggetto fisico)
Oggetto informativo  Dati concreti, codificato_da(oggetto
informativo, dati concreti)
Oggetto fisico  Dati concreti, digitalizzato_da(oggetto fisico, dati
concreti)
Regolamento  situazione, soddisfatto_da(regolamento,
situazione)
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sse: tutti o alcuni dei ruoli, compiti, parametri, etc. definiti nel
regolamento hanno una corrispondenza nella situazione
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Altri enigmi per le ontologie relative ai beni
culturali
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Artefatti object-oriented e process-oriented, ex. scultura vs. musica
Periodi artistici: intervalli di tempo, eventi, o descrizioni di stili?
Autenticità: valutazione basata su criteri locali
Interpretazione:
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entità rappresentate vs. figure simboliche, allusioni, rimandi
“intertestuali”
significato implicito ed esplicito, della critica e del pubblico
Metaphorical blending
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Riutilizzare l’esistente!
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“Magazzini” culturali
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Reingegnerizzazione di legacy design patterns
Tassonomie e campioni materiali
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Elicitazione dei modelli di razionalità degli esperti e degli
utenti reali
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The basic DDPO Design Pattern
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Information objects: a foundation for content
description and KCO
[a semiotic ontology design pattern]
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Formally …
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Class(DnS:information-object complete
intersectionOf(
DOLCE:social-object
restriction(DnS:about allValuesFrom(DOLCE:particular))
restriction(DnS:realized-by someValuesFrom(DOLCE:information-realization))
restriction(DnS:interpreted-by allValuesFrom(Actions:agent))
restriction(DnS:expresses allValuesFrom(DnS:description))
restriction(DnS:ordered-by someValuesFrom(DnS:information-encoding-system))))
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The definition says that information objects (IO):
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are ordered by some information encoding system
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are realized by some particular (an “information realization”)
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can express a description [and, if that description is satisfied by a situation,]
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can be about that situation, or some entity in its setting
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can be interpreted by agents that internally represent the description expressed by IOs
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
IO pattern for Dante’s Comedy
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Content objects
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“Content” is ambiguous. WordNet (v2.0):
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In KCO ontology, COs realize information objects
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Depicted object
Sum of what is perceived, discovered, or learned
What a communication that is about something is about
Everything that is included in a collection
MP3 file, eBook, JPEG image, QT movie, etc.
Either digital (computational objects) or analog (non-digital)
Therefore, COs are information realizations
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Semantic facets of (paid) content objects
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Content descriptions: provides the propositional content that is announced
by a digital content on an abstract level.
Community descriptions: information about the organisational structure
(roles, rights and obligations) by which a content product can be used and
information that influences trust such as certificates and brand name
information.
Business descriptions: describes the business and legal requirements
during information and negotiation phases. After a purchase, contracts will
be enforced according to mutually agreed rights and obligations.
Presentation descriptions: describes the presentation modes to which the
information of a content product can be adapted to by rendering and other
application-specific means.
Trust and Security descriptions: content must be associated with some
measure of trust for the end user, and for the content provider, there must
be some security features which guarantee that the content will not be
illegally copied or otherwise misappropriated.
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Aligning Knowledge Content
Objects with a Foundational Ontology
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A kind of information
object in DOLCE!
Are physical data structures (realize a frame - a data structure - for content objects),
hence they are information realizations
Generic KCO: realizes a maximally generic frame (a -unique- ontological schema)
Domain-anchored KCO: specializes a generic KCO by realizing an ontological schema
about the community and business elements. Furthermore, it commits its instances to a
domain specific ontology which can be as broad as desired
KCO Prototype (Master Copy): instantiates a domain-anchored KCO (by filling at least
some of the schema slots) and contains, at a certain point in time, a particular digital
content including all semantic annotations required by the corresponding domainanchored KCO
KCO Instance (Copy) : it also instantiates a domain-anchored KCO, but is treated as a
“copy” of a prototypical KCO, e.g. generated when a user is granted access to a content
object. Depending on the contract, this copy can change over time, through alterations
made by the owner. For example, somebody may buy a MIDI backing track for a pop
song, in order to modify it, e.g. by adding her own voice to it, or changing some parts
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
KCO (master or copy layer) formalization
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Class(KCO:KCO complete
KCO:physical-data-structure
restriction(DnS:realizes someValuesFrom(intersectionOf(
KCO:data-structure
restriction(KCO:instantiates someValuesFrom(intersectionOf(
KCO:data-structure
restriction(DnS:realized-by someValuesFrom(KCO:domain-KCO))))))))
restriction(KCO:realizes-frame-for someValuesFrom(KCO:content-object))
restriction(KCO:content someValuesFrom(DOLCE:particular))
restriction(KCO:time-based-rendition someValuesFrom(KCO:script))
restriction(KCO:interaction-based-rendition someValuesFrom(KCO:script))
restriction(KCO:usage-context someValuesFrom(DnS:plan))
restriction(KCO:user-task someValuesFrom(DnS:task))
restriction(KCO:content-user someValuesFrom(unionOf(
DnS:organization Collectives:collective DnS:role)))
restriction(KCO:contract-semantics
someValuesFrom(CommonSenseMapping:contract))
restriction(KCO:negotiation-semantics someValuesFrom(KCO:negotiation-protocol))
restriction(KCO:pricing-semantics someValuesFrom(KCO:pricing-scheme))
restriction(KCO:trust-value someValuesFrom(KCO:trust-region))
restriction(KCO:mappable-to allValuesFrom(KCO:ForeignClass)))
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Complementary axioms for KCO facets
(examples)
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SubClassOf(
restriction(KCO:realizes-frame-for someValuesFrom(
restriction(DnS:realizes someValuesFrom(
restriction(DnS:about someValuesFrom(DOLCE:particular)))))
restriction(KCO:content someValuesFrom(DOLCE:particular)))
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SubClassOf(
restriction(KCO:realizes-frame-for someValuesFrom(
restriction(DnS:realizes someValuesFrom(
restriction(DnS:expresses someValuesFrom(DOLCE:particular)))))
restriction(KCO:content someValuesFrom(DOLCE:particular)))
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EquivalentClasses(
restriction(KCO:user-task someValuesFrom(DnS:task))
restriction(KCO:usage-context someValuesFrom(intersectionOf(
DnS:Plan
restriction(DnS:defines someValuesFrom(DnS:task)))))
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Foundational
Ontology
is-defined-in
information object
realises
CD: Content Description
CO: Community Semantics
BS: Business Semantics
PR: Presentation Semantics
SD: KCO Self-Description
AC: Access Semantics
CD
CO
BS
KCO Structure
SD
PR
AC
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Foundational
is-defined-in
Ontology
Domain
Ontology
realises
CD: Content Description
CO: Community Semantics
BS: Business Semantics
PR: Presentation Semantics
SD: KCO Self-Description
AC: Access Semantics
information object
Domain-Model
CD
CO
BS
KCO Structure
SD
PR
AC
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Foundational
is-defined-in
Ontology
information object
CD: Content Description
CO: Community Semantics
BS: Business Semantics
PR: Presentation Semantics
SD: KCO Self-Description
AC: Access Semantics
realises
Domain
Ontology
Domain-Model
CD
CO
BS
KCO Structure
SD
PR
AC
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Foundational
is-defined-in
Ontology
information object
CD: Content Description
CO: Community Semantics
BS: Business Semantics
PR: Presentation Semantics
SD: KCO Self-Description
AC: Access Semantics
realises
Domain
Ontology
Domain-Model
CD
CO
BS
KCO Structure
SD
AC
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
PR
KCCA architecture
Applications / Interaction layer
GUI
KCO API
KCO Operations
Env. API
API extensions
KCCA Services
Business
semantics
KCCA
Registry
Domain-specific
Services
Community
description
Presentation
description
KCCA
Manager
Applic-spec.
Services
KCCA
Propositional
content
...
Reasoning
Services
Task Services
Reasoning
Engine
Task
Execution
Env.
KCTP
Services
Ser
DSer
Send
Rec
Network
Resource
Integration S.
V
V
C
C
W
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
Metokis service taxonomy
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
PRESENTATION LAYER
APPLICATION LAYER
COMMUNICATING WITH
OTHER KCCA NODES
Response KCTP Message
HTTP Message
HTTP Message
Request KCTP Message
KCTP Message
RDF Model
HTTP Sender/Receiver Servlet
HTTP Message
Serializer
KCTP Message RDF
Model
HTTP Message
HTTP Sender/Receiver
De-Serializer
KCTP Message
Check/ Get / Register
KCCA Service
Local System Registry
KCTP Router
KCCA Service
KCTP Message
KCTP Message
|_S1_| |_S2_| |_S3_|…………………...|_SN_|
SERVICES CONTAINER
Repository Services
KCO Services
Registry Services
METOKIS WORLD
METOKIS REPOSITORY API
WRAPPER
DATABASE
DATABASE
Components in KCCA/KCTP.
KCTP Handler consists of KCTP Router, HTTP Sender Receiver, HTTP Sender
Receiver
Servlet,
De-Serializer
and
Serializer.
Laboratorio
di Ontologia
Applicata,
CNR-ISTC,
Roma/Trento
KCO in the real World
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Three layers
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Content
The actual content of the KCO
| Human readable (e.g. contract.pdf, salzburg.jpg)
| Machine readable (e.g. config.xml, rss_newsfeed.xml, ...)
| Analog content (e.g. A book located at urn:room3:shelf2:loc43)
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Content Description Layer
Access, format and encoding information (MM-Facet)
| Provides a referable placeholder to any content or content segment
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Semantic Layer
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The actual knowledge of the KCO
Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
KCO in the real World
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This layering holds for all facets
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! That means that each facet may include content, e.g.:
The contract facet may include the human readable contract.pdf as
content in addition to the semantic statements in the semantic layer
of the facet
| The propositional content facet provides a semantic description of
the domain, but the current and approved XML-Document can still
be used
| Even the MM-Metadata facet may include a MPEG7 or Dublin Core
File in addition to the semantic statements part of this facet
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Laboratorio di Ontologia Applicata, CNR-ISTC, Roma/Trento
KCO in the real World
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Advantages of this approach
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KCOs do not break existing Applications
Content of the KCO provides compatibility to existing components
(Even tasks provided by humans)
| Newly developed XML-Standards can be used in combination with
KCOs
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Seamless migration to Semantic Web Technologies
It’s not necessary to provide a “complete” ontological description of
the problem domain
| Concentration on some key requirements is possible
| Steadily improvement of the semantic description based on
feedback and future requirements
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