of food, while T2FFO focus on the cooked food
modelling. However, these ontologies were not
available for used by others. Thus, they merely
become our references for building the ontology.
The food ontology by Cantais et al., (2005) was
imported to MyFELO as was available for others to
use.
4.3 Conceptualization: Enumerate
Important Terms
The first task in conceptualization phase is to list all
the related important terms of the domain to be
included in the ontology. The aim of this activity is
to create a comprehensive list of important terms for
the key concepts. For example, important food-
related terms are nutrients data for food – energy,
carbohydrate, protein, fat, fibre,
sodium, cholesterol and serving size;
mealtime that is suitable for food, food
allergy, cultural and religious that is
associate with a food, food groups i.e. starch,
vegetables, fruits, milk and
yogurt, meat and meat substitutes
and fats; different types of food, such as raw,
processed and cooked food, and so on.
Intermediate representations (IRs) is the tool
proposed by METHONTOLOGY (Gómez-Pérez et
al., 2004) to model the conceptualize knowledge.
The set of IRs represent the conceptual model in
tabular or graph notations. We adapt the IRs idea in
building MyFELO conceptual model.
4.4 Conceptualization: Define Class
and Class Hierarchy
This phase starts with defining the class. From the
list that obtained from the previous task, the terms
that represent a class was selected. One of the way to
identity the term as a class by looking at the term
that describe object, having independent existence
rather than terms that describe these objects (Noy
and Mcguinness, 2001).
Next, the classes were arranged into a superclass-
subclass hierarchy, or known as taxonomy. Uschold
and Gruninger (1996) proposed three approaches in
defining class hierarchy i.e. top-down, bottom-up
and middle-out. The selection of which approach to
apply is mainly depend on how an ontologist views
the domain. Since we think of foods by
differentiating the most general concept first, thus,
we opted to top-down approach. Herein class and
concept are used interchangeably.
The taxonomic relations in OD101 are referring
to the Frame ontology and the OKBC ontology
(Gómez-Pérez et al., 2004). Both of these ontologies
are knowledge representation ontologies. Among the
taxonomic relations discussed in OD101 are:
subclass-of, superclass-of, disjoint-decomposition
and instance-of. The subclass-of is based on “is-a”
relation. A class B is a subclass of A if and only if
every instance of B is also instance of A. For
example, cereal is a subclass of starch; since every
cereal grains is under starch food group. Superclass-
of relation is the inverse of subclass-of relation.
Thus, starch is the superclass for cereal. Disjoint-
decomposition relation is refers to disjoint classes,
where there is no common instances between them.
Cereal, rice and wheat was set as disjoint classes,
thus, any instance in one class cannot be an instance
of another class. OD101 also explains regarding on
the multiple inheritance, another subclass-of
taxonomic relation. This relation allows a class to be
subclass of several classes.
4.5 Conceptualization: Define
Properties of Classes
Properties are relation between two things also
known as binary relations. From the list of terms
created at step 4.3, the remaining of important terms
are probably the properties of the classes. The
examples of remaining terms are food’s energy,
carbohydrate, protein, fat, fiber,
sodium, serving size and allergy of a
food.
In OD101, for each property in the list, we need
to associate which classes it belongs. Subclass
inherits the properties of their superclass. Thus,
property should relate to the most general class that
belongs to it. However, this technique is no longer
available for Protégé. Protégé is the ontology tool
that support OD101. Thus, for this step, we refer to
the tutorial of building OWL ontologies using
Protégé 4 (Horridge, 2011) Object property and data
property are two main types of property in OWL.
The first link an individual to an individual namely
relationships between individual, while the latter
link an individual to data literal which they describe
relationships between an individual and data values.
From the remaining important terms list, we
identified the two main types of property. Object
property link between an individual with an
individual, while data property link between an
individual with data literal. For example, food’s
energy, carbohydrate, protein, fat and fiber are data
property, where the data literal is float. Allergy,