2 resultados para FORMULATIONS

em QSpace: Queen's University - Canada


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Strategic supply chain optimization (SCO) problems are often modelled as a two-stage optimization problem, in which the first-stage variables represent decisions on the development of the supply chain and the second-stage variables represent decisions on the operations of the supply chain. When uncertainty is explicitly considered, the problem becomes an intractable infinite-dimensional optimization problem, which is usually solved approximately via a scenario or a robust approach. This paper proposes a novel synergy of the scenario and robust approaches for strategic SCO under uncertainty. Two formulations are developed, namely, naïve robust scenario formulation and affinely adjustable robust scenario formulation. It is shown that both formulations can be reformulated into tractable deterministic optimization problems if the uncertainty is bounded with the infinity-norm, and the uncertain equality constraints can be reformulated into deterministic constraints without assumption of the uncertainty region. Case studies of a classical farm planning problem and an energy and bioproduct SCO problem demonstrate the advantages of the proposed formulations over the classical scenario formulation. The proposed formulations not only can generate solutions with guaranteed feasibility or indicate infeasibility of a problem, but also can achieve optimal expected economic performance with smaller numbers of scenarios.

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This project investigates the English-language life writing of diasporic Iranian Jewish women. It examines how these women have differentially imagined their diasporic lives and travels, and how they have in turn been imagined and accepted or rejected by their audiences. In the first chapter, I use “home” as a lens for understanding three distinct life writing texts, showing how the authors write about what it means to have a home and to be at home in contrasting and even contradictory ways. I show how, despite potential hegemonic readings that perpetuate unequal relationships and a normative definition of the ideal home, the texts are open to multiple contestatory readings that create spaces for new formulations and understandings. In the second chapter, I look more closely at the intersections between trauma stories and the life writing of Iranian Jewish women, and I argue that readers use life writing texts about trauma to support an egocentric reconstruction of American democracy and dominance. I also show how a critical frame for understanding trauma can yield interpretations that highlight, rather than ignore, relationships of power and privilege. In the final chapter of the thesis, I present a case study of two online reading groups, and I show that communal reading environments, though they participate in dominant discourses, are also spaces where resistance and subversion can develop.