This paper presents a Parallel Hybrid Evolutionary Metaheuristic for the Period Vehicle Routing Problem (PVRP). The PRVP generalizes the classical Vehicle Routing Problem by extending the planning period from a single day to M days. The algorithm proposed is based on concepts used in Parallel Genetic Algorithms and Local Search Heuristics. The algorithm employs the island model in which the mig...

Dealing with ill-defined problems, where the actual values of input parameters are unknown or not directly measurable, is generally not an easy task. In this paper, we propose a hybrid metaheuristic approach, incorporating a sampling-based simulation module, in order to enhance the robustness of the final solutions. Empirical application to the classical mean-variance portfolio optimization pro...

This paper addresses a realistic variant of the Hybrid Flow Shop (HFS) problem, based on a real microelectronics manufacturing environment. Firstly, the formulation of a Mixed Integer Linear Programming (MILP) model for optimally solving the problem is provided. Then, two metaheuristic procedures are presented: the former is a genetic algorithm based on an encoding/decoding method well-known in...

In this paper, we consider scheduling of project networks under minimization of total weighted resource tardiness penalty costs. In this problem, we assume constrained resources are renewable and limited to very costly machines and tools which are also used in other projects and are not accessible in all periods of time of a project. In other words, there is a dictated ready date as well as a d...

Metaheuristic algorithms are well-known optimization tools which have been employed for solving a wide range of optimization problems so far. In the present study, a simple optimization (SOPT) algorithm with two main steps namely exploration and exploitation, is provided for practical applications. Aside from a reasonable rate of convergence attained, the ease in its implementation and dependen...

The majority of scheduling metaheuristics use indirect representation of solutions as a way to efficiently explore the search space. Thus, a crucial part of such metaheuristics is a “schedule generation scheme” – procedure translating the indirect solution representation into a schedule. Schedule generation scheme is used every time a new candidate solution needs to be evaluated. Being relative...

The majority of scheduling metaheuristics use indirect representation of solutions as a way to efficiently explore the search space. Thus, a crucial part of such metaheuristics is a “schedule generation scheme” – procedure translating the indirect solution representation into a schedule. Schedule generation scheme is used every time a new candidate solution needs to be evaluated. Being relative...

No-wait job-shop scheduling (NWJSS) problem is one of the classical scheduling problems that exist on many kinds of industry with no-wait constraint, such as metal working, plastic, chemical, and food industries. Several methods have been proposed to solve this problem, both exact (i.e. integer programming) and metaheuristic methods. Cross entropy (CE), as a new metaheuristic, can be an alterna...

Given the NP-Hard nature of many optimization problems, it is often impractical to obtain optimal solutions to large-scale problems in reasonable computing time. For this reason, heuristic and metaheuristic search approaches are used to obtain good solutions fast. However, these techniques often struggle to develop a good balance between local and global search. In this paper we propose a hybri...

This paper studies the multi-stage supply chain system (MSSCM) controlled by the kanban mechanism. In the kanban system, decision making is based on the number of kanbans as well as batch sizes. A kanban mechanism is employed to assist in linking different production processes in a supply chain system in order to implement the scope of just-in-time (JIT) philosophy. For a MSSCM, a mixed-integer...