Faceted Classification Scheme ODP
http://ontologydesignpatterns.org/wiki/Submissions:Faceted Classication Scheme
Bene Rodriguez-Castro
School of Electronics and
Computer Science
University of Southampton
Southampton, UK
b.rodriguez@ecs.soton.ac.uk
Hugh Glaser
School of Electronics and
Computer Science
University of Southampton
Southampton, UK
hg@ecs.soton.ac.uk
Les Carr
School of Electronics and
Computer Science
University of Southampton
Southampton, UK
lac@ecs.soton.ac.uk
Keywords
Faceted Classication, Normalisation, Multiple Classica-
tion Criteria
1. INTRODUCTION
The Faceted Classication Scheme (FCS) ODP is a Reengi-
neering ODP that transforms a non-ontological resource from
the eld of Library and Information Science, also known as
Faceted Classication Scheme, into an ontological resource.
The ontological resource corresponds to an OWL DL model
that results from a specic application of the Normalisation
ODP [4] [2] based on a series of (a) alignments between the
two conceptual models; and (b) transformation guidelines.
The FCS ODP targets a specic, very recurrent modeling
issue in ontology development, subject to the vulnerabil-
ity of ad-hoc modeling practices that could potentially lead
to unexpected or undesirable results in ontology artifacts.
The scenario consists of domain-specic concepts that can
be represented according to multiple alternative classica-
tion criteria. To the best of our knowledge, guidelines for
the conceptualization and representation of domain-specic
concepts prone to be described based on multiple (poten-
tially alternative) classication criteria, has not been explic-
itly considered in the context of ontology modeling for the
Semantic Web.
An extended and detailed version of all the sections that
follow and the rationale behind the FCS ODP is presented
at length in [5].
2. PATTERN DESCRIPTION
A FCS is dened as: \a set of mutually exclusive and
jointly exhaustive categories, each made by isolating one
perspective on the items (a facet), that combine to com-
pletely describe all the objects in question, and which users
can use, by searching and browsing, to nd what they need"
[1].
The Norm. ODP is classied as a\Good Practice"pattern
in the catalog of ODPs introduced in [2]. It can be applied
to any OWL DL ontology that consists of a polyhierarchy
where some semantic axes can be pointed. Each of those
axes will be a module.
The key similarity between these two conceptual models,
lies in the notion of (a) facet in FCSs; and (b) module (or
semantic axis) in the Norm. ODP. Both elements repre-
sent one perspective of the domain being modelled, a single
characteristic of division, a single criterion of classication
in their respective paradigm.
Library Sc. Ontology Modeling
FCS FCS ODP OWL Impl.
TDC :TDC owl:Class (primitive)
Faceti
:Faceti owl:Class (primitive)
:hasFaceti owl:ObjectProperty
FiTermj
:FiTermj owl:Class (primitive)
:FiTermjTDC owl:Class (def.) ()
Itemx :SpecificTDCx owl:Class (primitive)
Table 1: Alignment of a FCS to the Norm. ODP
owl:Thing
|-- :Faceti
|-- :FiTermj
|-- :TargetDomainConcept (or :TDC)
|-- () :FiTermjTDC
|-- :SpecificTDCx
owl:topObjectProperty
|-- :hasFaceti
() denotes a dened owl:Class.
Figure 1: FCS elements placed into the Norm. ODP
The main principle is to represent each facet as an inde-
pendent module or semantic axis. Following this principle
makes the application of the Norm. ODP almost straight-
forward. Moreover, the resultant ontology includes the rep-
resentation of the multiple alternative classication criteria
that were considered in the original FCS for the target do-
main concept.
Table 1 summarizes the alignment of the elements in the
generic structure of both conceptual models. This alignment
enables the conversion of a FCS into an OWL DL ontology
by applying the Norm. ODP, where:
 TDC denotes the target domain concept (or domain
of discourse) of the FCS.
 Faceti denotes one of the facets of the FCS.
 FiTermj denotes one of the terms of Faceti.
 Itemx denotes one the items from the domain of dis-
course to be classied.
Figure 1 depicts the placement of the elements of a generic
FCS into the generic structure of the Norm. ODP based on
the corresponding mappings from Table 1.

Agent: dishwasher, person
Form: gel, gelpac, liquid, powder, tablet
Brand Name: Cascade, Electrasol, Ivory, No Name,
Palmolive, President's Choice, Sunlight
Scent: green apple, green tea, lavender, lemon,
mandarin, ocean breeze, [...]
Effect on Agent: aroma therapy (subdivisions:
invigorating, relaxing)
Special Property: antibacterial
Figure 2: Example of\Dishwashing Detergent"FCS.
3. PATTERN USAGE EXAMPLE
Figure 2 presents the facets and terms of a FCS example
in the domain of \Dishwashing Detergent" from [1].
To apply the FCS ODP, the elements in the generic on-
tology structure (derived from the Norm. ODP) in Fig. 1
are populated with the facets and terms of the \Dishwashing
Detergent" FCS example in Fig. 2, according to the align-
ments specied in Table 1. The overall normalised ontology
model obtained as a result is presented in Fig. 3. A version
of the complete normalised ontology model for the \Dish-
washing Detergent" FCS example in [1] is available online1
in RDF/XML format.
4. RELATED WORK
The FCS ODP considered previous work that dened map-
pings between dierent semantic models and OWL ontolo-
gies such as the Resource Space Model (RSM) [6] and the
concept of Faceted Lightweight Classication Ontology [3].
A detailed discussion is available in [5].
5. CONCLUSIONS
The FCS ODP has presented an initial set of basic design
guidelines to develop an OWL DL ontology model that sup-
ports the representation of multiple alternative classication
criteria of a specic domain concept. These guidelines pro-
vides a partial solution to potentially hazardous ad-hoc prac-
tices in the development of such ontology models, putting
forward a systematic and t-for-purpose approach.
6. REFERENCES
[1] W. Denton. How to make a faceted classication and
put it on the web. Online, November 2003.
http://www.miskatonic.org/library/facet-web-
howto.html.
[2] M. Egana-Aranguren. Role and Application of Ontology
Design Patterns in Bio-ontologies. PhD thesis, School
of Computer Science, University of Manchester, 2009.
[3] F. Giunchiglia, B. Dutta, and V. Maltese. Faceted
lightweight ontologies. In A. Borgida, V. K. Chaudhri,
P. Giorgini, and E. S. K. Yu, editors, Conceptual
Modeling: Foundations and Applications, volume 5600
of Lecture Notes in Computer Science, pages 36{51.
Springer, 2009.
1http://purl.org/net/project/enakting/ontology/detergent fcs norm
owl:Thing
|-- :Agent
|-- :Person
|-- :Dishwasher
|-- :Form
|-- :Gel
|-- :Gelpac
|-- (... rest of terms in the facet "Form")
|-- :BrandName
|-- :Cascade
|-- :Electrasol
|-- (... rest of terms in the facet "Brand Name")
|-- :Scent
|-- :GreenApple
|-- :GreenTea
|-- (... rest of terms in the facet "Scent")
|-- :EffectOnAgent
|-- :AromaTherapy
|-- :Invigorating
|-- :Relaxing
|-- :SpecialProperty
|-- :Antibacterial
|-- :DishwashingDetergent (:TDC)
|-- () :ManualDishDetergent
|-- () :DishwasherDishDetergent
|-- () :GelDishDetergent
|-- () :GelpacDishDetergent
|-- () (... rest of subclasses for each term
in the facet "Form")
|-- () :CascaseDishDetergent
|-- () :ElectrasolDishDetergent
|-- () (... rest of subclasses for each term
in the facet "Brand Name")
|-- () :GreenAppleDishDetergent
|-- () :GreenTeaDishDetergent
|-- () (... rest of subclasses for each term
in the facet "Scent")
|-- () :AromaTherapyDishDetergent
|-- () :InvigoratingDishDetergent
|-- () :RelaxingDishDetergent
|-- () :AntibacterialDishDetergent
|-- :PresidentsPersonLiquidAntibacterial
|-- :PalmoliveAromaTherapyLavenderYlangYlang
|-- :SpecificDishDetergent3
|-- (... rest of specific dish detergent classes
:SpecificDishDetergentx to classify)
owl:topObjectProperty
|-- :hasAgent
|-- :hasForm
|-- :hasBrand
|-- :hasScent
|-- :hasEffectOnAgent
|-- :hasSpecialProperty
() denotes a dened owl:Class.
Figure 3: Normalised ontology structure of the
\Dishwashing Detergent" FCS.
[4] A. L. Rector. Modularisation of domain ontologies
implemented in description logics and related
formalisms including owl. In K-CAP '03: Proceedings of
the 2nd international conference on Knowledge capture,
pages 121{128, New York, NY, USA, 2003. ACM.
[5] B. Rodriguez-Castro, H. Glaser, and L. Carr. How to
reuse a faceted classication and put it on the semantic
web. In The 9th International Semantic Web
Conference (ISWC), June 2010.
[6] H. Zhuge, Y. Xing, and P. Shi. Resource space model,
owl and database: Mapping and integration. ACM
Trans. Internet Technol., 8(4):1{31, 2008.