| Delta Incremental Transformation & Transition Model (DITT model) | first: 2011-10-12 last: 2011-11-09 |
In this section the developments of artifacts will be considered as a chain
of processes. Then these processes will be addressed in relation to the artifact
usage. Based on this analysis a reference model of the design process in its
chain will be defined.
The chain of developments
In the example sections various examples are given to illustrate that artifact
developments are almost always based on previous artifacts. This conclusion can
also be found in the works of several authors:
Design process of artifacts in general can be understood as actions to improve existing artifacts, radical novelties are vanishingly rare. [Preston 2009: 216]
The most typical characteristic of designers activities in the `reproduction process': is the improvement of existing solutions. [Houkes and Vermaas 2010]
The expression `reproduction process', as used by Houkes and Vermaas is probably influenced by their attempt to apply their ICE theory into the domain of biology. I think that with their reference to evolution theories, they remain too close to the biological concepts where only random changes during the evolution process occur during the 'reproduction' process.[id. 60-66] In artifact design a direction precedes the 'reproduction' process.
They worked out a model of the design activities and introduced the representation (R) of the artifact (p) as the base for the next design process (represented by a wavy arrow), as indicated in figure 3.1.
Houkes and Vermaas' sequential model
The chain of developments approach at first view might be acceptable, it then raises two main questions:
How could it ever have started?
Can this process be accounted for by basic cognitive processes?
The first question is addressed by two examples below.The second question will be addressed in chapter 4.
The start of the incremental processes
Functional artifacts are characterized by their function. A genealogical exercise can reduce the whole collection of artifacts, that surround us, to a limited number of basic functions. One can even state that basic revolutionary steps in artifact developments are very exceptional.
In architecture, Buildings started with the shelter of a large leaf as chimpanzees use to keep dry. The first key step, by early homoids, has been the fixing of leaves to branches instead of holding the leaves. From there it just has been a continuous series of small steps to huts and from there to houses by applying other materials and then more recently to skyscrapers. Most of the major steps were made possible by innovations of materials such as concrete, reinforced concrete and in particular prestressed concrete with in parallel developments of cast iron and steel. Only a few major conceptual inventions can be identified such as the arch construction, first widely applied by the Romans. This usage of the arch was unique, none of the large cultures such as the Egyptian, Greek, Chinese or South American cultures made such use of the concept.
In transport, it started with rolling materials over tree trunks or stone balls, the key step, the invention of the wheel formed the base of all the means of road transport we now have available. In the conclusion of her chapter Artifacts}, Lynne Baker states that when automobiles were invented, a new kind of thing came in to existence and it changed the world}. (\cite{Baker2007}: 66) In the context of her analysis that might be a valid observation. In the context of the above defined thesis there is no real moment of invention of the automobile she refers to. In retrospect replacing the horse by an engine was inevitable. The first steam powered car was realised in 1769 by Nicolas-Joseph Cugnot, more than a century before the petrol fueled combustion engines of Daimler and Benz (1885) that formed the base of today's cars. [Pollard1995]The first vehicles with an engine were just based on the concept of a carriage with the horse replaced by an engine. It took more than half a century to get the type of automobile that really changed the world. The only really revolutionary step in transport, after that of the wheel, was the introduction of the airplane with the concept to separate the carrying function of the wings from the moving force, whereas birds have these combined.
In parallel with the incremental developments from primitive basic functions, the development of artificial power generation should be mentioned as a main key in technological developments. In addition to that, the scientific knowledge and understanding of electricity and magnetism yielded a wealth of application opportunities.
The 'Use Plan' concept
The most essential aspect of functional artifacts is their relation to the usage. As a consequence the knowledge of the use and usage environment is an essential input for the design and the design improvement.
Houkes and Vermaas introduce the notion use plan as an action theory based element to account for understanding both the usage and the design of artifacts, including the relation between these two, in a wider, application, context. They specify plans as complex mental items consisting of considered actions, based on beliefs about the world, ourselves, and the effect of actions, similar to a belief or an intention. [Houkes 2010: 18]
They add that plan in daily use already includes a good amount of (practical) rationality. This includes the following context related elements: effectiveness, goal consistency, means-end consistency and belief consistency. [id.: 39-41] ('Belief' in the domain of action theory usually combined with desire, has a meaning close to knowledge and expectation.)These elements of rationality can then be used to evaluate artifact use and design}.
To illustrate the product design related to the use plan, Houkes and Vermaas consider the design of a nail clipper. However, the specific design process is not covered by their analysis. (see comparison with the PPA approach in appendix 1
The Delta Incremental Transformation & Transition model (DITT model)
Based on the above we can combine the chain concept with the use plan. However, the use of representation (R) as the input for the design process needs to be modified. It is not just incomplete in practice, it conflicts with the basic assumptions of pragmatism and phenomenology with their integrated concept of subject and object. The reference model for further analyses is visualized in figure 3.2
figure 3.2 D2T reference model
Here P stands not just for predecessor (p) as in figure 3.1, but P includes all information related to p. That means that, there is more than representation p and representation R (Reference information as mentioned with fig. 3.2) it can include test results, user reports and even misfunctional or broken down items, etc.
Delta Transformation model and Transition model: DITT
Delta indicating the small incremental steps. In general two stages can be distinguished. First one or more alternatives will pop-up usualy not for the artifact as a whole but for certain elements or aspects (such as material or form). Then these alternatives go through one or two selection, evaluaation processes as visualised in a simplified diagram below. During these processes various means can be included such as drawings and prototypes, but more often these stages will not be visible as these are interactive processes with reality in the mind of the designers (Transformations).
Often the transition has the form of a combination. The combination of two different materials by early homonides is usually seen as one of the most significant steps in human evolution. The capability to combine functions is the most important transition mechanism in todays artifact design of advanced complex functional items. W. Brian Arthur considers this as the key of the evolution of technology and calls it combinatorial evolution.[The Nature of Technology Arthur 2009: 22]
causal
actions