| 1. |
- Quttineh, Nils-Hassan, et al.
(författare)
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A Time-Indexed Generalized Vehicle Routing Model and Stabilized Column Generation for Military Aircraft Mission Planning
- 2015
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Ingår i: OPTIMIZATION, CONTROL, AND APPLICATIONS IN THE INFORMATION AGE: IN HONOR OF PANOS M. PARDALOSS 60TH BIRTHDAY. - Cham : SPRINGER. - 9783319185675 - 9783319185668 ; , s. 299-314
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Konferensbidrag (refereegranskat)abstract
- We introduce a time-indexed mixed-integer linear programming model for a military aircraft mission planning problem, where a fleet of cooperating aircraft should attack a number of ground targets so that the total expected effect is maximized. The model is a rich vehicle routing problem and the direct application of a general solver is practical only for scenarios of very moderate sizes. We propose a Dantzig-Wolfe reformulation and column generation approach. A column here represents a specific sequence of tasks at certain times for an aircraft, and to generate columns a longest path problem with side constraints is solved. We compare the column generation approach with the time-indexed model with respect to upper bounding quality of their linear programming relaxations and conclude that the former provides a much stronger formulation of the problem.
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| 2. |
- van den Bergh, Jeroen, et al.
(författare)
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What if solar energy becomes really cheap? A thought experiment on environmental problem shifting
- 2015
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Ingår i: Current Opinion in Environmental Sustainability. - : Elsevier BV. - 1877-3435 .- 1877-3443. ; 14, s. 170-179
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Tidskriftsartikel (refereegranskat)abstract
- Solving one environmental problem may often invoke or intensify another one. Such environmental problem shifting (EPS) is a neglected topic in global sustainability research. Indeed, it is difficult to study as it requires the merging of insights from various research areas. Here we identify relevant studies, and provide an illustration and guidelines for the systematic study of EPS. As a modest thought experiment to illustrate the relevance of EPS, we consider solutions to scarcity of energy resources and climate change that, due to their extreme nature, may lead to considerable environmental problem shifting. We qualitatively assess the likely environmental and socioeconomic impacts of three hypothetical energy futures to highlight the possibility that as we resolve one environmental problem, another may be aggravated. We further present a set of guidelines to study EPS in a systematic and focused way. Here we stress that shifting can be mediated by biophysical as well as socioeconomic mechanisms, which means that its analysis requires a genuine interdisciplinary effort.
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