Transportation Research Record: Journal of the Transportation Research Board, 2014
ABSTRACT The U.S. Army Corps of Engineers oversees dredging in hundreds of navigation projects an... more ABSTRACT The U.S. Army Corps of Engineers oversees dredging in hundreds of navigation projects annually, through its fleet of government equipment and through individual contracts with private industry. The research presented here sought to examine the decision to allocate dredge resources to projects systemwide under necessary constraints. These constraints included environmental restrictions on when dredging could take place in response to the migration patterns of turtles, birds, fish, and other wildlife; dredge equipment resource availability; and varying equipment productivity rates that affected project completion times. The paper discusses problem definition and model formulation of optimal dredge fleet scheduling within environmental work windows. In addition, a sensitivity analysis was conducted to provide decision makers with quantitative insights into dredging program efficiency gains that could be realized systemwide if environmental restrictions were relaxed. Opportunities exist to provide decision makers with quantitative insights into how efficiencies might be obtained if targeted research were to show that particular restricted periods could be relaxed without adverse consequences to sensitive and endangered species.
Transportation Research Part E: Logistics and Transportation Review, 2014
ABSTRACT In this paper, we present a two-stage mixed integer programming (MIP) interdiction model... more ABSTRACT In this paper, we present a two-stage mixed integer programming (MIP) interdiction model in which an interdictor chooses a limited amount of elements to attack first on a given network, and then an operator dispatches trains through the residual network. Our MIP model explicitly incorporates discrete unit flows of trains on the rail network with time-variant capacities. A real coal rail transportation network is used in order to generate scenarios to provide tactical and operational level vulnerability assessment analysis including rerouting decisions, travel and delay costs analysis, and the frequency of interdictions of facilities for the dynamic rail system.
Transportation Research Record: Journal of the Transportation Research Board, 2014
ABSTRACT The U.S. Army Corps of Engineers oversees dredging in hundreds of navigation projects an... more ABSTRACT The U.S. Army Corps of Engineers oversees dredging in hundreds of navigation projects annually, through its fleet of government equipment and through individual contracts with private industry. The research presented here sought to examine the decision to allocate dredge resources to projects systemwide under necessary constraints. These constraints included environmental restrictions on when dredging could take place in response to the migration patterns of turtles, birds, fish, and other wildlife; dredge equipment resource availability; and varying equipment productivity rates that affected project completion times. The paper discusses problem definition and model formulation of optimal dredge fleet scheduling within environmental work windows. In addition, a sensitivity analysis was conducted to provide decision makers with quantitative insights into dredging program efficiency gains that could be realized systemwide if environmental restrictions were relaxed. Opportunities exist to provide decision makers with quantitative insights into how efficiencies might be obtained if targeted research were to show that particular restricted periods could be relaxed without adverse consequences to sensitive and endangered species.
Transportation Research Part E: Logistics and Transportation Review, 2014
ABSTRACT In this paper, we present a two-stage mixed integer programming (MIP) interdiction model... more ABSTRACT In this paper, we present a two-stage mixed integer programming (MIP) interdiction model in which an interdictor chooses a limited amount of elements to attack first on a given network, and then an operator dispatches trains through the residual network. Our MIP model explicitly incorporates discrete unit flows of trains on the rail network with time-variant capacities. A real coal rail transportation network is used in order to generate scenarios to provide tactical and operational level vulnerability assessment analysis including rerouting decisions, travel and delay costs analysis, and the frequency of interdictions of facilities for the dynamic rail system.
Uploads
Papers by Ridvan Gedik