In this work, a study on Variable Neighborhood Search algorithms for multi-depot dial-a-ride problems is presented. In dial-a-ride problems patients need to be transported from pre-specified pickup locations to pre-specified delivery locations, under different considerations. The addressed problem presents several constraints and features, such as heterogeneous vehicles, distributed in differen...

In this paper, we present an effective approach based on the variable neighborhood search (VNS) for solving multilevel lot-sizing (MLLS) problems. Two kinds of neighborhood search strategies, i.e., move at first improvement (MAFI) and move at best improvement (MABI), are adopted to improve the performance of proposed algorithm. Computational experiments are carried out on 96 benchmark problems ...

This paper proposes a way to combine the Mesh Adaptive Direct Search (MADS) algorithm, which extends the Generalized Pattern Search (GPS) algorithm, with the Variable Neighborhood Search (VNS) metaheuristic, for nonsmooth constrained optimization. The resulting algorithm retains the convergence properties of MADS, and allows the far reaching exploration features of VNS to move away from local s...

Developing a reasonable and efficient emergency material scheduling plan is of great significance to decreasing casualties property losses. Real-world (EMS) problems are typically large-scale possess complex constraints. An evolutionary algorithm (EA) one the effective methods for solving EMS problems. However, existing EAs still face challenges when dealing with or equality To handle above cha...

This paper presents the investigation of an evolutionary multi-objective simulated annealing algorithm with variable neighborhoods to solve the multi-objective multicast routing problems in telecommunications. The hybrid algorithm aims to carry out a more flexible and adaptive exploration in the complex search space by using features of the variable neighborhood search to find more non-dominate...

Dial-a-Ride problems (DARPs) arise in many urban transportation applications. The core of a DARP is a pick and delivery routing with multiple vehicles in which customers have ride-time constraints and routes have a maximum duration. This paper considers DARPs for which the objective is to minimize the routing cost, a complex optimization problem which has been studied extensively in the past. S...

This work presents the application of Variable Neighborhood Search (VNS) based algorithms to the High School Timetabling Problem. The addressed model of the problem was proposed by the Third International Timetabling Competition (ITC 2011), which released many instances from educational institutions around the world and attracted seventeen competitors. Some of the VNS algorithm variants were ab...

The nurse rostering problem refers to the assignment of nurses daily shifts according required demand each shift and day, with consideration for operational requirements nurses’ preferences. This is known be an NP-hard problem, difficult solved using exact solution methods especially large size instances. Mostly, this modeled soft hard constraint, objective set minimize violations constraints. ...