scholarly journals A constraint-programming based decomposition method for the Generalised Workforce Scheduling and Routing Problem (GWSRP)

Author(s):  
E. Bourreau ◽  
T. Garaix ◽  
M. Gondran ◽  
P. Lacomme ◽  
N. Tchernev
Author(s):  
D. Guimarans ◽  
R. Herrero ◽  
J. J. Ramos ◽  
S. Padrón

This paper presents a methodology based on the Variable Neighbourhood Search metaheuristic, applied to the Capacitated Vehicle Routing Problem. The presented approach uses Constraint Programming and Lagrangean Relaxation methods in order to improve algorithm’s efficiency. The complete problem is decomposed into two separated subproblems, to which the mentioned techniques are applied to obtain a complete solution. With this decomposition, the methodology provides a quick initial feasible solution which is rapidly improved by metaheuristics’ iterative process. Constraint Programming and Lagrangean Relaxation are also embedded within this structure to ensure constraints satisfaction and to reduce the calculation burden. By means of the proposed methodology, promising results have been obtained. Remarkable results presented in this paper include a new best-known solution for a rarely solved 200-customers test instance, as well as a better alternative solution for another benchmark problem.


2021 ◽  
Author(s):  
Alex Luciano Roesler Rese ◽  
Fabricio Bortoluzzi ◽  
Victor Hugo Fagundes Wachsmann ◽  
Rafael Ballottin Martins

Companies of chartered transport of passengers need to manage routes with boarding points, based on the location of the passengers. As the number of routes grow, the task of manually manage and optimize routings becomes inviable. The vehicle routing problem characterizes inside this scenario, branching into specific problems, that need different solutions for each case. Meta-heuristics are usually used to build solver algorithms for these problems. Constraint programming was chosen for helping build the solver. The main objective of the work was, to develop a system performing the solution of routings in an automatized way, by utilization of constraint programming and meta-heuristic algorithms. To minimize transport costs, travel time, and maximize the use of vehicles in an efficient and planned manner. The tests were carried out in conjunction with a routing administrator, to validate the use of the application within the research field. From the evaluations made, they demonstrated the utility of the software within its purpose. Of which it was observed that the product of this research, helped in the construction of an automated fleet consulting tool, being able to dynamically point out the distribution and operationality of a fleet of chartered vehicles in the transportation of passengers.


2017 ◽  
Vol 5 (1) ◽  
pp. 92-115
Author(s):  
Siamak Layeghy ◽  
Farzaneh Pakzad ◽  
Marius Portmann

In this paper, we introduce SCOR (Software-defined Constrained Optimal Routing), a new Software Defined Networking (SDN) Northbound Interface for QoS routing and traffic engineering. SCOR is based on constraint-programming techniques and is implemented in the MiniZinc modelling language. It provides a powerful, high-level abstraction layer, consisting of 10 basic constraint-programming predicates. A key feature of SCOR is that it is declarative, where only the constraints and utility function of the routing problem need to be expressed, and the complexity of solving the problem is hidden from the user, and handled by a powerful generic solver. We show that the interface (set of predicates) of SCOR is sufficiently expressive to handle all the known and relevant QoS routing problems. We further demonstrate the practicality and scalability of the approach via a number of example scenarios, with varying network topologies, network sizes and number of flows.


2020 ◽  
Vol 118 ◽  
pp. 104930 ◽  
Author(s):  
Dilson Lucas Pereira ◽  
Júlio César Alves ◽  
Mayron César de Oliveira Moreira

2018 ◽  
Vol 25 (4-5) ◽  
pp. 753-792 ◽  
Author(s):  
Haneen Algethami ◽  
Anna Martínez-Gavara ◽  
Dario Landa-Silva

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