Dear all,
This list frequently rises the difficulties and ambiguities involved
in modeling the notion of design (as in “product design”) and
engineering model. We are now developing an ontology that must
represent these concepts and we are facing those same issues. We
would like to seek some advice from people in this list.
The ontology we are working on must deal with a conceptualization
already in use by a specific application. This application deals
with automated production lines that produce different types of
artifacts (hammers, for example). These artifacts are produced
according to their respective specific designs.
However, it is not clear what are these designs and what are their
relationship with the respective artifacts. Intuitively, we consider
artifacts as subtypes of physical objects. We consider designs to be
mental or abstract entities that specify instances of an artifact to
be built (but not *how* they are built, in terms of list of
actions). For instance, a design of a type of hammer should specify
what are its attributes, parts, structure and materials.
That definition of design makes it quite similar to the very notion
of concept. The argument going on in our group is whether there is
any essential difference at all between then, and if so, what are
they relationship. Both seem to “abstract” the properties of a class
of individuals. Differences could be the level of detail they are
intended to specify. Another point of view emphasizes that there is
a fundamental difference between the concept/class of Hammer (for
example) and the design of specific hammers. Nevertheless, their
main content of a class/concept seems to be very similar, but we are
not sure whether this similarity necessarily implies the identity
between these notions.
The differences become even more difficult to spot when we consider
the design and its description. We distinguish the design from its
description as a piece of text or a blueprint. A single design can
have many individual descriptions.
One of the requirements of this project is that the description of a
design must explicitly refer to entities provided by the ontology.
For example, consider a design for a new kind of hammer, which
should be 40 cm in length. This design has a description (say, in
first order logic) “Ax NewHammer(x) -> length(x, 40cm).”
According to our requirements, NewHammer and length must relate to
the “Hammer” and the property “length” provided in our ontology. We
could, for instance, rewrite that formula to “Ax NewHammer(x) ->
Hammer(x) ^ length(x, 40cm)”. However, in this case we start to have
the description of a design of Hammer is striking similar to the
description of a subconcept of Hammer.
Some people in our group quite understandably have problems with
that position, arguing that the content of the description of a
design should only reflect an existing concept, but it cannot be the
same as the description of a concept (to justify the subsumption
relation in the second formula, for instance). Other argue that the
description of a design *is* the description of a concept, justified
by the lack of differences between them.
The question is: what is the relation between design and
concept/class? We considered two possible answers:
1-The concept/class Hammer’ is its own design. In this sense, it
seems that the notion of design is only useful as a modeling tool to
group different possible descriptions of the same entity. It seems
to be interesting to think about the instances here. In this point
of view, both the concept and design of NewHammer collapse in the
same entity, abstracting the same class of individuals.
2- The concept/class NewHammer and its design are different things.
An instance of NewHammer is different from an instance of Design
that specifies the class of NewHammer. In this point of view, it
seems that we are proposing a new type of relationship that holds
between instances and classes, which is not the instantiation
relation. In this relationship (maybe called specifies), a specific
instance (of design) specifies a new class of entities in the
ontology. That is, this new class comes to existence due to the very
existence of an instance of Design that specifies it.
best,
--
Sandro Rama Fiorini
Phd Candidate
Institute of Informatics
Federal University of Rio Grande do Sul (UFRGS)
Website: www.inf.ufrgs.br/~srfiorini
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