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This research discusses the sequence of inbound and outbound aircrafts on a mixed operation single runway at an airport. Influenced by the climate, the target airport cannot meet landing conditions. As a result, aircrafts have to land at other nearby airports. Since the sequence for considering both normal and alternate aircrafts arriving in a fixed time window becomes difficult, few studies have considered this situation. Therefore, in this article, we propose a mixed integer programming model for formulating and possibly solving this problem to minimize total delay time. Since the problem is NP-hard, we propose an Improved Immunoglobulin-based Artificial Immune System (IIAIS) to find an optimal or near optimal solution to the considered aircraft scheduling problem. Using the problem instances from the OR library and a real-life practical case, we empirically evaluate the performance of the proposed algorithm. The results show that the proposed algorithm performs better than other existing algorithms.

Vehicles on urban freeway off-ramps often have difficulty in exiting due to congestion on the arterial routes. The resulting queue on the off-ramp generates a spillover onto the mainstream of the urban freeways, leading to serious problems such as decreased capacity and traffic safety. In this study, a signal control model for minimizing the total delay of off-ramps and connected downstream arterial roads is developed. The results demonstrate the proposed model's ability to reduce the delay of off-ramp and freeway mainstream. The developed model calculates an optimal signal time at off-ramps and arterial intersections by a linear programming technique with a variety of variables such as traffic volume, link length, and queue length. The simulation results show that as the traffic volumes of both off-ramps and arterials approach the saturation flow, the proposed model can increase the number of throughputs at off-ramps, decrease the average delay of whole links, and prevent the decrease of capacity on the mainstream of urban freeways by reducing the queue length at off-ramps. Especially, the reductions in the average delay time of whole links are 21.5% and 13.0% compared to T7F model and Sequential Control Model, respectively. [ABSTRACT FROM AUTHOR]