(Georgia Institute of Technology, 2006-01)
Duncan, Scott Joseph; Paredis, Christiaan J. J.; Bras, Berdinus A.
Often in the early stages of the engineering design process, a decision maker lacks the information needed to represent uncertainty in the input parameters of a performance model. In one particular form of severely deficient information, a nominal estimate is available for an input parameter, but the amount of discrepancy between that estimate and the parameter’s true value, as well as the implications of that discrepancy on system performance, are not known. In this paper, the concepts and techniques of information-gap decision theory (IGDT), an established method for making decisions robust to severely deficient information, are examined more closely through application to a design problem with continuous design variables. The uncertain variables in the chosen example problem are parameters of a probability distribution, so the relationship between IGDT and design approaches considering precise and/or imprecise probabilities is explained. Insight gained from a walkthrough of the design example is used to suggest the types of problems an IGDT approach will or will not effectively solve as well as potential limitations that could be encountered when solving more complex problems.
(Georgia Institute of Technology, 2003)
Carlier, Taco; Duncan, Scott Joseph; Boks, Casper B.; Stevels, Ab; Bras, Berdinus A.
The environmental benchmarking procedure as
developed by the Design for Sustainability Lab of
Delft University of Technology and the
Environmental Competence Centre of Philips
Consumer Electronics has been applied to TVs
sold in the market in three continents: North
America (USA), Europe and Asia (China). For
each region three or four products of different
brands have been considered. In total some fifty
parameters, which are relevant for the
environmental performance have been measured.
These measurements allow making calculation of 2002 another project was completed in
life cycle performance of the products (based on
the Eco Indicator 95 system).
The results show big differences in all categories; no brand scores consistently best in all focal areas. It will be concluded that although TVs are seemingly a mature product, different design tradition, different supplier base and difference in speed of latest technology make that in practice differences up to 50% in life cycle performance have been found.
Also between products sold in the three regions of the world clear differences were found (although not as big as between best and worst brand performances.) Only partly this observation can be explained by differences in for instance
environmental legislation. It will be speculated to what extent the structure of the value chain is responsible.
It will be concluded that environmental
benchmarking is a powerful tool to systematically track down design improvements and to check on
supplier relationships.