In industrial product development applications that I am familiar with a
design concept is more general than a design specification. so
Also designs are more restrictive than descriptions which are more
restrictive than concepts.
Ax NewHammerDesign(x) implies NewHammerDescription(x)
implies NewHammerConcept(x)
However, the conceptual hierarchy is different from physical
objects. That is, a design object and a description object are not
physical objects. The FOL statement “Ax NewHammer(x) -> length(x,
40cm)” could certainly be in either of NewHammerDescription or
NewHammerDesign, but is not a hammer. The conceptual classes and the physical
classes are related by a NewHammerModelOF relation
Ax,y NewHammerDesignModelOf(x,y) implies
NewHammerDesign(x) and HammerPhysicalObj(y).
With the above distinction between the conceptual objects and physical
objects, the statement that “the description of a design must explicitly
reference the ontology” would be replaced by ”description and the design
specification of the physical artifacts must explicitly reference the
ontology”. The description of the design refers to design artifacts. A
specific named design instance might have multiple design artifacts with
different data types related to it.
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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