An optimization model for land allocation between bioenergy crops and grain crops and an optimization model for identifying the most vulnerable links in a transportation network

摘要

This thesis consists of two separate studies. The first part is for land allocation betweengrain crops and bioenergy crops. The second part is for identifying most vulnerable links in a transportation network. Optimization models are used in both studies.The first part of this thesis focuses on analyzing farmers\u27 land allocation between bioenergy crops and grain crops and the impact of bioenergy crop contract price on farmers\u27 land allocation. An optimization model for a centralized farmer is proposed. The model simulates farmers\u27 objective by maximizing their prots. Under the consideration of crop rotation constraints, farmers\u27 land allocation is optimized. A case study including corn, soybean and switchgrass for Iowa is conducted. Our model can compute the threshold of switchgrass contract price, which can provide guidance in contract negotiation between farmers and bioenergy producers.The second part of the thesis concerns identifying the most vulnerable links in a transportation network. The problem can be viewed as a game between an \u22attacker\u22 and network users. The attacker represents natural disasters or man-made accidents that could reduce network capacity, whereas network users decide their travel patterns in response to the attacker\u27s action. By maximizing the attacker\u27s disruption to the network, our model can identify the most vulnerable links in the network, which provides the most effective strategy to strengthen the robustness of the network. We conducted a case study for a sixteen-link network with two demand scenarios and the most vulnerable links are found. For that particular network, reducing the most vulnerable 0.7% of total capacity doubles the system travel time. Therefore, maintaining full capacity on these most vulnerable links is crucial for the system.