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Modeling Integrated Decisions For A Municipal Water System With Recourse And Uncertainties: Amman, Jordan, David E. Rosenberg, Jay Lund
Modeling Integrated Decisions For A Municipal Water System With Recourse And Uncertainties: Amman, Jordan, David E. Rosenberg, Jay Lund
Civil and Environmental Engineering Faculty Publications
Stochastic mixed-integer optimization is used to identify a portfolio of long- and short-term supply and conservation actions for a municipal water system to cost-effectively accommodate a distribution of water shortages. Alternative robust, grey-number, and best/worst case formulations systematically explore implications of uncertainties in action costs, life spans, water volumes gained or saved, shortage levels, and shortage probabilities. A detailed example for Amman, Jordan considers 23 potential actions. Results show: (1) remarkable consistency occurs across the different modeling approaches. (2) Conserving water—reducing leakage and targeting select customers to install water efficient appliances—plays an important and growing role over time. (3) A …
Shades Of Grey: A Critical Review Of Grey-Number Optimization, David E. Rosenberg
Shades Of Grey: A Critical Review Of Grey-Number Optimization, David E. Rosenberg
Civil and Environmental Engineering Faculty Publications
A grey number is an uncertain number with fixed lower and upper bounds but unknown distribution. Grey numbers find use in optimization to systematically and proactively incorporate uncertainties expressed as intervals plus communicate resulting stable, feasible ranges for the objective function and decision variables. This article critically reviews their use in linear and stochastic programs with recourse. It summarizes grey model formulation and solution algorithms. It advances multiple counter-examples that yield risk-prone grey solutions that perform worse than a worst-case analysis and do not span the stable feasible range of the decision space. The article suggests reasons for the poor …