Abstract
Graphs are commonly used to represent related elements and relationships among them. Signed graphs are a special type of graphs that can represent more complex structures, such as positive or negative connections in a social network. In this work, we address a combinatorial optimization problem, known as the Cyclic Minimum Sitting Arrangement, that consists of embedding a signed input graph into a cycle host graph, trying to locate in the embedding positive connected vertices closer than negative ones. This problem is a variant of the well-known Minimum Sitting Arrangement where the host graph has the structure of a path graph. To tackle the problem, we propose an algorithm based on the Multi-Armed Bandit method that combines three greedy-randomized constructive procedures with a Variable Neighborhood Descent local search algorithm. To assess the merit of our proposal, we compare it with the state-of-the-art method. Our experiments show that our algorithm outperforms the best-known method in the literature to date, and the results are statistically significant, establishing itself as the new state of the art for the problem.
Publication
Computers and Operations Research

Artificial Intelligence Phd Student
Marcos Robles graduated in Software Engineering from the Rey Juan Carlos University in 2022. He is working here as a predoctoral researcher focusing in Graph Layout Problems.

Phd in Artificial Intelligence
Sergio Cavero was born Madrid (Spain) on September 24, 1997. He graduated in Software Engineering from Universidad Politécnica de Madrid in 2019. During his undergraduate studies he made a stay at the University of Bradford (UK). In addition, he was awarded twice with the ‘Beca de Excelencia of the Comunidad de Madrid, and also awarded for the Best Final Degree Project. Later, he completed a Master’s Degree in Artificial Intelligence at the same university (UPM) obtaining awards for Best Academic Record (‘Premio José Cuena’) and Best Master’s Thesis. He academic results lend him be beneficiary of one of the ‘Ayudas Para la Formación de Profesorado Universitario (FPU)’, funded by the Spanish Government. He is currently carrying out his doctoral thesis at the Universidad Rey Juan Carlos, supervised by Professors Abraham Duarte and Eduardo G. Pardo. His main research interests focus on the interface among Computer Science, Artificial Intelligence and Operations Research. Most of his publications deal with the development of metaheuristics procedures for optimization problems modeled by graphs.