Person:
Bras, Berdinus A.

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Publication Search Results

Now showing 1 - 7 of 7
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    Applying Information-Gap Decision Theory to a Design Problem having Severe Uncertainty
    (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.
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    Managing Uncertainty in Environmentally Benign Design and Manufacture
    (Georgia Institute of Technology, 2006) Bras, Berdinus A. ; Paredis, Christiaan J. J.
    When making design decisions in environmentally benign design and manufacture, the decision maker is often faced with extreme uncertainty. Due to a lack of understanding of the complex dynamics of environmental and societal systems, it is very difficult to judge the impact different design alternatives have on the environment, the economy and the society, especially in the distant future. In this paper, two formalisms are illustrated for making design decisions under extreme uncertainty. The formalisms are probability bounds analysis and info-gap decision theory. We introduce the basic concepts for both formalisms, discuss the advantages and limitations, and identify under which circumstances they are useful in the context of design decision making. One can think of both decision methods as having a built-in sensitivity analysis allowing the decision maker to judge whether a decision can be made confidently based on the current information, or whether additional information needs to be gathered.
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    Environmentally Conscious Design & Manufacturing Group: Research Overview to SRL
    (Georgia Institute of Technology, 2005-07-26) Bradley, Bert ; Duncan, Scott ; Muir, Michael Christopher ; Reap, John J. ; Roman, Felipe ; Bras, Berdinus A.
    Researchers in the ECDM program will develop methodologies and decision support tools that integrate the best business practices with those that produce superior environmental and social performance. Our research products will enable corporations to recognize, pursue and embrace triple bottom line goals
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    Environmental Benchmarking of Medium-sized TVs Sold in North America, Europe and Asia (China)
    (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.
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    Research Strategies: Understanding and Measuring "Performance" in the Paper Industry
    (Georgia Institute of Technology, 2001-10-23) Carmichael, Carol ; Bras, Berdinus A. ; Shipley, Scott ; McGinnis, Leon F. ; Zhou, Chen ; Newcomb, P. J. ; Bargmann, Melissa Ann
    From a sustainability perspective, we would define "performance" in the pulp and paper industry by the relative effectiveness of a mill or enterprise in transforming its capital resources— financial, technological, natural, and social—into value-added products and processes. Such an assessment would encompass the entire product life-cycle and its associated financial, environmental and social effects. It would extend beyond the production of a particular product to include the extraction and beneficiation of raw materials, the production processes, distribution of the product to customers, use of the product by the customers, and recycling or remanufacture of the product or its constituents into new products. The focus of our CPBIS project is narrower than the sustainability perspective, but is intended to provide a foundation for more complex assessments in the future. Our initial focus is on a particular enterprise, a manufacturing facility and its products, and the relevant measures of financial, technological and natural capital resource effectiveness. We will explore ways in which resource data (mass, energy, water, etc.) from steady-state and dynamic models of a production facility can be combined with financial data from an existing financial model used by the firm. For comparison, we will also develop an activity-based cost (ABC) model that integrates financial data with data on other resources used by the manufacturing site. Future studies will address the product life-cycle perspective on effectiveness (with respect to environmental and financial performance) and the relationship between performance measures of a facility and the enterprise. Our goal is to develop a tool to support both operational and strategic decision making by providing simultaneous views of the facility/enterprise from manufacturing process, financial, and environmental perspectives. Our partners in this project are Dr. Paul Stuart, the NSERC chair in process integration at the Ecole Polytechnique in Montreal, Quebec, Canada, his students, and the representatives from a paper mill in northern Ontario. The Ecole Polytechnique team will develop the steady-state and dynamic process models of the facility as well as provide an initial study on the existing financial model used by the firm. The CPBIS/Georgia Tech team will develop the enhanced ABC model of the facility. The Georgia Tech/Ecole Polytechnique team will explore performance metrics and other data interpretation schemes that combine financial data with material/energy data and take into consideration contextual factors associated with environmental effects.
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    Computer-aided design for de- and remanufacturing
    (Georgia Institute of Technology, 1998) Bras, Berdinus A.
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    Enhancing reusability by design
    (Georgia Institute of Technology, 1998) Bras, Berdinus A.