In this paper, we study the hierarchical hub network design problem with a ring-star-star structure. In this problem, the hubs are located in two layers. In the first layer, central hubs (main hubs) are located in a ring structure, and in the second layer, secondary hubs are located. Each...

Combinatorial optimization problems are usually NP-hard and the solution space of them is very large. Therefore the set of feasible solutions cannot be evaluated one by one. Artificial Bee Colony (ABC), Particle Swarm Optimization (PSO) and Genetic Algorithms (GA) are metaheuristic techniques...

The flexible job-shop scheduling problem (FJSP) is a typical mixed-integer linear programming problem, which plays an important role in operation research. A variable neighborhood search (VNS) enhance genetic algorithm (VNSeGA) is presented to minimize makespan of FJSP in this paper. In VNSeGA,...