Using the Unified Foundational Ontology (UFO) for

Grounding Legal Domain Ontologies

Mirna El Ghosh

, Habib Abdulrab

, Hala Naja

and Mohamad Khalil

LITIS, INSA du Rouen, Saint Etienne du Rouvray, Rouen, France

Lebanese University, Faculty of Sciences, Tripoli, Lebanon

CRSI Research Center, Lebanese University, Faculty of Engineering, Tripoli, Lebanon

Keywords: Ontology Grounding, Conceptual Modelling Process, Ontology-Driven Conceptual Modelling, ONTOUML,

Foundational Ontology, UFO, Legal Ontologies.

Abstract: In this paper, the concept of ontology-driven conceptual modelling is outlined where grounding a modular

legal domain ontology in the unified foundational ontology UFO is overviewed. The domain ontology is

modularized in four independent modules. The top ontology modules are discussed in this work: upper and

core. The ontology modelling language OntoUML is used for the conceptual modelling process.

1 INTRODUCTION

In this paper, the concept of grounding domain

ontologies in foundational ontologies is discussed

specifically in the legal domain. Generally, the

grounding concept is defined by placing a

foundation. The ontology grounding is introduced by

Harnad who claimed that existing approaches to

ontology design pose the classical symbol grounding

problem (Harnad, 1990). Harnad wondered how a

logical theory of a concept, that can be explicit, easier

to communicate and axiomatized, is feasibly related

to a human understanding of that same concept and

avoiding constructing an abstract theory or model for

another model. Moreover, how are its primitives

grounded outside the formal system? In other words,

how the semantic interpretation of a formal symbol

system can be made intrinsic to the system, rather

than just parasitic on the meanings in human head

(Harnad, 1990). Furthermore, some studies such as

(Kohn, 2003) illustrated the ontology grounding by

avoiding resorting endlessly from one formal system

to another in explaining the meaning of symbols.

They claim that if ontologies are not grounded in

something that their users share, they will be of very

limited practical use. Therefore, ontology

engineering methods have to supply a list of concepts

(or at least of the kinds of concepts) considered

meaningful outside the formal theories (Kohn, 2003).

In other words, ontology grounding is expressed

by the application of foundational ontologies in

conceptual modelling for building domain ontologies.

In this context, grounding domain ontologies using

existent foundational ontologies refers to the (partial)

reuse process of the basic categories of a foundational

ontology.

Foundational ontologies are the most general and

formal ontologies (Borgo and Leitão, 2004).

Theoretically, they are well-founded domain

independent systems of categories that have been

successfully used to improve the quality of

conceptual models and semantic interoperability

(Guizzardi et al., 2010). Moreover, reuse of

foundational ontologies can facilitate and speeding up

the ontology development process by preventing to

reinvent known modelling solutions (Keet, 2011).

In other words, ontology grounding is expressed

by the application of foundational ontologies in

conceptual modelling for building domain ontologies.

In this context, grounding domain ontologies using

existent foundational ontologies refers to the (partial)

reuse process of the basic categories of a foundational

ontology.

Foundational ontologies are the most general and

formal ontologies (Borgo and Leitão, 2004).

Theoretically, they are well-founded domain

independent systems of categories that have been

successfully used to improve the quality of

conceptual models and semantic interoperability

(Guizzardi et al., 2010). Moreover, reuse of

foundational ontologies can facilitate and speeding up

El Ghosh M., Abdulrab H., Naja H. and Khalil M.

Using the Uniﬁed Foundational Ontology (UFO) for Grounding Legal Domain Ontologies.

DOI: 10.5220/0006507302190225

In Proceedings of the 9th International Joint Conference on Knowledge Discovery, Knowledge Engineering and Knowledge Management (KEOD 2017), pages 219-225

ISBN: 978-989-758-272-1

the ontology development process by preventing to

reinvent known modelling solutions (Keet, 2011).

Actually, we motivate to build a legal domain

ontology for modelling the legal norms of the

criminal domain serving as a basis for legal reasoning

purposes. More specifically, the legal domain

ontology will be used as a knowledge base for a legal

decision support system. In this context, a

foundational and legal core ontologies are reused for

grounding this ontology. Therefore, the conceptual

architecture of the legal domain ontology is

modularized in different modules including the upper

and core modules that serve for the grounding aspect.

The modularization technique is inspired from the

literature that suggests that legal ontologies may be

distinguished by the levels of abstraction of the

discipline they represent (Guizzardi et al., 2010) -

(Borgo, 2011), with the key distinction being between

different levels such as upper, core and domain.

From these perspectives, a modular middle-out

approach is introduced to support the grounding

process of the legal domain ontology (El Ghosh et al.,

2016). The approach is based on ontology

modularization process where the legal domain

ontology is modularized into four independent

modules stated on different levels: upper, core,

domain and domain-specific. The upper and core

modules are constructed for the grounding using a

top-down strategy that performs ontology-driven

conceptual modelling process guided by reusing

foundational and legal core ontologies such as the

unified foundational ontology (UFO) (Guizzardi and

Wagner, 2005a) and the LKIF-Core (Hoekstra et al.,

2007) respectively. The upper module represents the

most general concepts and relations that cover all the

domains (such as Agent, Act and Action). The core

module provides a definition of structural knowledge

in the legal domain. For instance, concepts, such as

Legal_Source, Legal_Act and Legal_Document, are

common for all the legal fields (criminal, civil, etc.).

Meanwhile, the domain and domain-specific modules

are extracted from the available sources of the

domain, such as legislation and codes, by applying a

bottom-up strategy as an ontology learning process

with the support of NLP techniques. For more details

about this strategy, refer to (El Ghosh et al., 2017).

At the end, the modules will be integrated together

to compose the global ontology (see Figure 1).

In this work, the top-down is discussed and the

upper and core modules are overviewed.

The remainder of this paper is organized as

follows: In section 2, the ontology-driven conceptual

modelling is overviewed. Section 3 presents the

unified foundational ontology UFO. The ontology-

grounding process is discussed in section 4. Finally,

section 5 concludes the paper.

Figure 1: Modular middle-out approach.

2 ONTOLOGY-DRIVEN

CONCEPTUAL MODELLING

As aforementioned, the top-down strategy of the

middle-out approach represents an ontology-driven

conceptual modelling process (ODCM) guided by

reusing foundational and legal core ontologies for

grounding the legal domain ontology. ODCM is

firstly introduced by Guarino et al. (Guarino and

Schneider, 2002).

Generally, conceptual modelling is defined as

“the activity of representing aspects of the physical

and social world for the purpose of communication,

learning and problem solving among human users”

(Mylopoulos, 1992). In other words, conceptual

modelling is concerned with identifying, analyzing

and describing the relevant concepts and constraints

of a domain with the help of a modelling language

that is based on a small set of basic meta-concepts

(Guizzardi et al., 2004).

In order to make conceptual modelling languages

more suitable for representing the real world and less

oriented by systems, the attention of researchers have

turned to philosophy where ontologies, dealing with

the modelling reality, represent a branch of it

(Verdonck, 2014).

Therefore, the ontologies were introduced in

order to provide a foundation for conceptual

modelling by expressing the fundamental elements of

a domain (Guarino, 1998). Moreover, ontologies are

used to analyze and improve existing conceptual

modelling languages (Wand, 1996). Thus,

ontological or ontology-driven modelling is

concerned with capturing the relevant entities of a

domain in an ontology of that domain using an

ontology specification language that is based on a

small set of basic, domain-independent ontological

categories (forming an upper level ontology)

(Guizzardi et al., 2004).

Recently, ontology-driven conceptual modelling

is defined by Guizzardi as the utilization of

ontological theories, coming from areas such as

formal ontology, cognitive science and philosophical

logics, to develop engineering artifacts (e.g.

modelling languages, methodologies, design patterns

and simulators) for improving the theory and practice

of conceptual modelling (Guizzardi, 2012). In other

words, ODCM aims at formalizing conceptual

modelling languages for reducing different kind of

interpretations of concepts (Kohn, 2003).

3 THE UNIFIED

FOUNDATIONAL ONTOLOGY

Generally, foundational ontologies define a range of

top-level domain-independent ontological categories,

which form a general foundation for more elaborated

domain-specific ontologies (Guizzardi and Wagner,

2005a), (Borgo, 2004). Various foundational

ontologies exist in the literature such as DOLCE

(Masolo, 2003) and UFO (Guizzardi and Wagner,

2005a). Four our work, UFO is the most convenient

for two main reasons: (1) its successful application in

a large number of domains ranging from natural

science domains such as Petroleum and Gas and

Electrophysiology of the heart to social domais such

as organizations, services and software (Griffo,

2015); (2) the fact that UFO comprises a rich theory

of relations and complex relational properties that is

absent in other foundational ontologies (Guizzardi,

2005c).

The unified foundational ontology UFO is an

example of a descriptive foundational ontology that

has been constructed for more than a decade

employing results from formal ontology, cognitive

psychology, linguistics, philosophical logics, but also

significant accumulated empirical and theoretical

results from the area of conceptual modelling in

computer science (Griffo, 2015). UFO is initially

proposed by Guizzardi and Wagner (Guizzardi and

Wagner, 2005a) and developed to support the

activities of both conceptual and organizational

modelling. Therefore, UFO permits the building of an

ontology by reusing some generic concepts such as

category, kind, subkind, relator, role and role mixin

where the ontologist does not need to rebuild these

concepts.

The concept kind, for instance, provides a

principle of application and a principle of identity for

its instances (Guizzardi, 2005b). It represents a rigid

concept, i.e., a class that applies necessarily to its

instances. In other words, instances of these types will

continue to be so as long as they exist in the model

(Guizzardi, 2005b). A kind can be described in a

taxonomic structure where its subtypes are also rigid

types known as subkinds (e.g., Man and Woman)

(Guerson et al., 2014).

The concept role, in turn, is an anti-rigid concept,

applying contingently to its instances (e.g., Offender,

Instigator).

A phase is an anti-rigid concept that it is defined

by a partition of a kind and whose contingent

instantiation condition is related to intrinsic changes

of an instance of that kind.

A relator (e.g. entities with the power of

connecting other entities) is a rigid concept and

existentially depends on the instances it connects

through mediation relations.

UFO is divided into three layered sets:

 UFO-A: ontology of objects, defines terms related

to endurants such as universal, relator, role,

intrinsic moment;

 UFO-B: ontology of events, defines terms related

to perdurants such as event, state, atomic event,

complex event;

 UFO-C: defines terms related to intentional and

social entities including linguistic aspects such as

social agent, social object, social role and

normative description.

The current work covers two fragments from UFO,

UFO-B and UFO-C, for grounding the legal domain

ontology in order to build the upper and core modules

since they define some basic concepts for the criminal

domain such as Agent, Intentional Moment, Action,

Event, and Normative Description. In order to make

possible the activity of conceptual modelling via

UFO, a conceptual modelling language, named

OntoUML (Benevides et al., 2009a) is used.

OntoUML is a well-founded modelling language that

allows modellers to formalize world-views in a

technologically neutral way, aiding in the solution of

such interoperability challenges (Benevides and

Guizzardi, 2009b). According to (Guerson et al.,

2014), this language has been successfully employed

in a number of industrial projects in several domains

such as Petroleum and Gas, News Information

Management, E-Government and Telecom.

OntoUML uses the ontological constraints of UFO as

modelling primitives and is specified above the UML

2.0 meta-model (Guizzardi, 2005b). To build,

evaluate and implement OntoUML models, a model-

based environment is needed such as the standalone

tool OLED (OntoUML Lightweight Editor)

(Benevides and Guizzardi, 2009b).

4 TOP-DOWN STRATEGY

As aforementioned, the top-down strategy represents

an ontology-driven conceptual modelling process

since it will be based on reusing UFO for grounding

the legal domain ontology. In this section, the strategy

and the resulted ontology modules, upper and core,

are overviewed.

4.1 Upper Module

The upper module consists of abstract concepts and

relations which are effectively independent of any

specific domain for grounding the legal domain

ontology. Concerning the conceptual modelling

process of the upper module, the ontology modelling

language OntoUML is used for representing the upper

concepts reused from UFO in order to compose the

upper ontology module (see Figure 2) (Guizzardi,

2005b).

Figure 2: Conceptualization process of upper module.

For a well-founded building of this module, a

partial reuse of existent validated foundational, or

top-level, ontologies can help. In the literature,

several works seek for reusing concepts from

foundational ontologies in order to support in

maintaining a well-structured construction of domain

ontologies that could serve as a future reusable

artifact (Torres et al., 2011). Thus, the upper module

is built by reusing the concepts and relations of the

unified foundational ontology UFO represented using

OntoUML as an ontology modelling language, in

order to form the conceptualization of the upper

module. Two main layers are partially reused from

UFO: UFO-C and UFO-B.

4.1.1 UFO-C

There are list of essential concepts in UFO-C to reuse

for building the upper module, mainly those related to

social entities such as Agents and Objects (see Figure

3).

Figure 3: Fragment of upper module in OntoUML.

Agents can be physical (e.g. Person) or social (e.g.

Organization) (see figure 4).

Figure 4: The concept Agent in upper module.

Figure 5: Object in upper module in OntoUML.

Objects are also categorized in physical (e.g.

book) and social objects (e.g. normative description)

(see Figure 5). Normative_Description defines one or

more rules/norms recognized by at least one

Social_Agent. Regulations and constitutions are

examples of normative description.

4.1.2 UFO-B

The ontology of perdurants, UFO-B, defines Event,

which is a basic concept in the criminal domain (e.g.

crime is an event), as a main category. In UFO-B,

events can be atomic or complex depending on their

mereological structure (Guizzardi et al., 2013).

Complex events are aggregations of at least two

events that can themselves be atomic or complex (see

Figure 6).

Figure 6: Event of upper module in OntoUML.

In UFO-B, an event can be an Action or

Participation (see Figure 7).

Figure 7: Event in upper module in OntoUML.

Actions are performed by agents and considered

as intentional events caused by intentions (see Figure

8).

Figure 8: Action in upper module in OntoUML.

Participation can be for agents and objects (see

Figure 9).

Figure 9: Participation in upper module in OntoUML.

Therefore, participation of an agent can be

intentional or unintentional (see Figure 10).

Figure 10: Agent_Participation in upper module in

OntoUML.

The intentional participations are actions and

termed here Action_Contribution.

4.2 Core Module

The core module is built by reusing the concepts and

relations of an existent validated legal core ontology

such as LKIF-Core (Hoekstra et al., 2007). Actually

the core concepts are represented in the unified

foundational ontology UFO, using OntoUML as an

ontology modelling language, in order to compose the

conceptualization of the core module which is

represented by the core ontology module (see Figure

11).

Figure 11: Conceptualization process of the core module.

Figure 12: Fragment of the core module.

Generally, core ontologies provide a broad view

of a given domain, such as the legal domain in this

study, suitable for different target domains such as

criminal and civil law (Guarino and Oberle, 2009). In

the domain of conceptual modelling, core ontologies

are used for providing real-world semantics for

conceptual modelling languages (Guizzardi and

Wagner, 2011). Concerning the core module, it

consists of concepts and relations that are common

across the domains of law and can provide the basis

for specialization into domain and domain-specific

concepts. In order to build this module, the legal core

ontology LKIF-Core (Hoekstra et al., 2007) have

been reused since it contains essential legal concepts

such as Medium, Document, Legal_Source,

Legal_Document, and Code. In this study, list of basic

concepts of LKIF-Core are represented using the

generic concepts of UFO (see Figure 12).

5 CONCLUSION

This paper discussed the application of foundational

and core ontologies in conceptual modelling for

grounding a well-founded legal domain ontology. A

case-study that describes the partial reuse of existent

validated ontologies such as the unified foundational

ontology UFO and the legal core ontology LKIF-Core

is presented. Throughout this study, we have

illustrated the importance of these ontologies in the

conceptual modelling process for building consistent

legal domain ontologies. In this paper, a modular legal

domain ontology is presented. The upper and core

modules are developed as a grounding modules for the

ontology. The modelling process of these modules is

discussed. The ontology modelling language

OntoUML has been used for this purpose since the

grounding process is based mainly on the unified

foundational ontology UFO. For the upper module,

concepts and relations from UFO-C and UFO-B have

been reused. For the core module, concepts and

relations from the legal core ontology LKIF-Core has

been reused by defining them in the context of UFO

using OntoUML.

After building the upper and core modules, they

will be integrated using semantic mappings such as

parent-child, or hierarchical relationships since they

are located on vertical conceptual levels. The

integration process will be applied as well for the

domain and domain-specific modules. At the end, the

global modular ontology will be used as a knowledge

base for a legal decision support system that performs

legal reasoning purposes.

ACKNOWLEDGEMENTS

This work has been supported by the European Union

with the European Regional Development Fund

(ERDF) under Grant Agreement n°HN0002134 in the

project CLASSE 2 (“Les Corridors Logistiques:

Application a la Vallee de la Seine et son

Environnement”), Lebanese University and the

National Support from the National Council for

Scientific Research in Lebanon (CNRS).

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