and overviews our upcoming research plans.
2 RELATED WORKS
Ontology alignment is a widely discussed topic,
frequently investigated in the available literature
((Shvaiko et al., 2018), (Shvaiko and Euzenat, 2011)).
The variety of (e.g. (Kolyvakis et al., 2018)) ap-
proaches usually define mappings between ontologies
as sets of pairs of complementary elements from two
ontologies. In other words, pairs of those elements
from ontologies describe the same part of the universe
of discourse. Those sets are then validated by means
of Precision and Recall measures ((Algergawy et al.,
2019)) using preprepared mappings treated as a refer-
ence.
This approach, despite being perfectly valid, has
two downsides. The first one is it measures only the
correctness of mappings in relation to the aforemen-
tioned references. Using Precision and Recall mea-
sures is impossible in practical applications, due to the
fact that no reference alignment exists. The second
disadvantage is the fact that such assessment takes
into account solely mappings, omitting the content of
ontologies that are matched.
There some research addressing the raised issues
by noticing those flaws and attempted to overcome
them (Thiéblin et al., 2020). In (Dragisic et al., 2016)
authors provide a survey on involving users in mea-
suring the quality of automated alignment algorithms.
Three aspects of human-centric evaluation are espe-
cially investigated: the profile of the user, the services
of the alignment system, and the user interface while
in (Leal et al., 2017) authors attempt to utilize the so-
called Ontology of Enterprise Interoperability to as-
sess different aspects of interoperability.
A similar approach can be found in (Ivanova et al.,
2017). The article proposes a "human-in-the-loop"
approach to overcome the difficulties when reference
alignments are unavailable. The main idea is based
on a tool called Matrix Cubes, which is used for visu-
alizing dense dynamic networks, this further supports
the interactive exploration of multiple ontology align-
ment in order to assess their quality. The research is
further extended in (Li et al., 2019).
The research found in (Solimando et al., 2017)
presents detecting and minimizing the violations
of the "conservativity principle". This is a situa-
tion where novel subsumption entailments between
classes from one of the mapped ontologies are marked
as unwanted.
This paper focuses on a different issue. While
approaches described above all focus on evaluating
the designated ontology alignments in order to check
their correctness, we attempt to address the change
factor of ontology alignments. Obviously, when
mapped ontologies evolve, it requires that their align-
ment evolve as well. Therefore, we would like to
provide a method for assessing how much knowl-
edge about the interoperability between ontologies
has been gained or lost. We claim that such a tool
can become very useful in practical applications of
ontologies and ontology alignment. Especially, when
large-scale ontologies (e.g. in (Kiourtis et al., 2019))
are mapped the knowledge about the degree to which
they can cooperate can be invaluable.
3 BASIC NOTIONS
Our research focuses on a mathematical model of an
ontology. We assume that a real world is defined as
a pair (A, V ) where: A is a finite set of attributes that
can be used to describe objects, V is a set of their
valuations (domains) such that V =
S
(a∈A)
V
a
, V
a
is a
domain of a particular attribute a. The following quin-
tuple defines an ontology as a (A, V)-based ontology:
O = (C, H, R
C
, I, R
I
) (1)
where: C is a set of concepts; H is a concepts’ hierar-
chy; R
C
is a set of relations between concepts, R
C
=
{r
C
1
, r
C
2
, ..., r
C
n
}, n ∈ N, such that r
C
i
∈ R
C
(i ∈ [1, n]) is
a subset of C × C; I is a set of instance identifiers;
R
I
= {r
I
1
, r
I
2
, ..., r
I
n
} is a set of relations between con-
cepts’ instances.
A concept’sc ∈ C structure from (A, V )-based on-
tology is defined as:
c = (id
c
, A
c
, V
c
, I
c
) (2)
where id
c
is an identifier of the concept c, A
c
is a set of
its attributes, such that A
c
⊆ A, V
c
is a set of attributes
domains (formally: V
c
=
S
(a∈A
c
)
V
a
), I
c
is a set of
instances of the concept c. We write a ∈ c to denote
that an attribute a belongs to concept c set of attributes
A
C
.
The hierarchy of concepts H is a distinguished re-
lation between concepts. Formally, hierarchy is a set
concept pairs (H ⊂ C ×C), where a single pair of con-
cepts (c
1
, c
2
) ∈ H represents the fact that c
1
is an an-
cestor of c
2
. The position of a concept in a hierar-
chy allows us to deduce how much specific knowl-
edge it carries a concept. Thus, concept c
2
is more
detailed than c
1
. This remark will be used for esti-
mating knowledge increase. Based on hierarchy H
we can define subtree in the following way:
Definition 1. For given ontology O, and c ∈ C by
Subtree(O, c) we call a subtree of H such that ¬∃c
0
∈
{x|(x, x
0
) ∈ Subtree(O, c)} : (c
0
, c) ∈ Subtree(O, c).
ENASE 2021 - 16th International Conference on Evaluation of Novel Approaches to Software Engineering
174