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[ontolog-forum] Representing design

To: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Sandro Rama Fiorini <srfiorini@xxxxxxxxxxxx>
Date: Tue, 15 Oct 2013 14:00:17 -0300
Message-id: <525D74A1.3060105@xxxxxxxxxxxx>
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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