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Multi-objective swarm intelligence approach for bias mitigation in decision-making software
(Elsevier, 2026) Vega Cruz, Lucía; Vega Rodríguez, Miguel Ángel; Universidad de Extremadura. Departamento de Tecnología de los Computadores y de las Comunicaciones
At present, many decisions, even decisions that affect people’s lives, are increasingly made by decision-making software. For this reason, it is really important to avoid decision-making software being biased, that is, it needs to assure fairness. As decision-making software is generally based on classification models, its bias can be mitigated in three different stages: pre-processing, in-processing, and post-processing. However, despite the importance of fairness on these models, there are very few proposals for the post-processing stage that are able to mitigate bias without reducing the original model’s accuracy. Therefore, this problem should be addressed as a multi-objective problem, optimizing at the same time both fairness and accuracy. Taking this into account, we propose a Multi-Objective Swarm Intelligence approach for BIas Mitigation (MOSIBIM), which combines dominance-based multi-objective optimization (with techniques such as Pareto fronts, niching, and reference points), population-based evolutionary computation, swarm intelligence, and convergence-stagnation differentiation. In order to analyze the improvements that this proposal produces over other approaches in the literature, its results on fairness and accuracy have been compared with the results obtained by other five approaches, optimizing different classification models and in six distinct real-life scenarios which have various types of bias. The results of MOSIBIM show great improvements on fairness in comparison with the other approaches, as it reaches improvement percentages of 91.7 % and, on average, the results are always in the range of 66.6 % to 76.6 % of improvement. Furthermore, the proposed approach has been able to improve the original model’s accuracy in all the studied cases.
Perspectivas de futuro del sector extremeño de vacuno de carne: resultados de un estudio Delphi
(Caja de Ahorros de Badajoz, 2002) Mesías Díaz, Francisco Javier; Escribano Sánchez, Miguel; Rodríguez de Ledesma Vega, Antonio; Pulido García, Francisco; Universidad de Extremadura. Departamento de Economía; Universidad de Extremadura. Departamento de Producción Animal y Ciencias de los Alimentos
En este capítulo se expone el estudio Delphi realizado con el fin de predecir las tendencias y los cambios esperados en el sector productor de vacuno de carne de Extremadura. Para llevar a cabo este estudio, se realizó la selección del panel de expertos, para lo cual se contó con la colaboración de un grupo de personas con elevado conocimiento del sector de vacuno de carne. Posteriormente, se elaboró un cuestionario para la primera ronda y otro para la segunda que trató de recoger los aspectos más importantes del sector que debían ser analizados. Dichos cuestionarios se dividieron en cinco bloques temáticos: regulación del mercado de la carne de vacuno, la encefalopatía espongiforme bovina, consumo de carne de vacuno, sector bovino de carne en España y sector bovino de carne en Extremadura. Tras ello, se exponen los resultados del estudio siguiendo la ordenación temática de los cuestionarios para finalmente presentar las conclusiones más importantes.
El comercio exterior
(Caja de Ahorros de Badajoz, 2002) González Blanco, Raquel; Sánchez de Gómez, Lyda Amparo; Universidad de Extremadura. Departamento de Economía
Este capítulo se ocupa de analizar la evolución del comercio mundial, la evolución del comercio exterior español, así como la evolución del comercio exterior de Extremadura durante el año 2001. Finalmente, hay un apartado dedicado al comercio exterior agrario centrado principalmente en Extremadura.
Effect of surface-active contaminants on bubble bursting yielding the smallest first-emitted droplet
(Cambridge University Press, 2026) Rodríguez Aparicio, Sergio; Cebrián García, Alberto; Vega Rodríguez, Emilio José; Montanero Fernández, José María; Cabezas Martín, María Guadalupe; Universidad de Extremadura. Departamento de Ingeniería Mecánica, Energética y de los Materiales; Universidad de Extremadura. Departamento de Ingeniería Eléctrica, Electrónica y Automática; Universidad de Extremadura. Instituto de Computación Científica Avanzada (ICCAEx)
We study the bursting of a bubble on a liquid free surface under critical conditions, i.e. those leading to the minimum (maximum) size (velocity) of the first-emitted jet droplet. We consider the effect of a surfactant remaining in the monolayer during the cavity collapse and jetting (the surfactant is considered as insoluble). Our experiments show that a tiny amount of surfactant considerably increases (decreases) the droplet radius (velocity). The volume of the first-emitted droplet increases by a factor of 20 for a concentration that produces an insignificant reduction in the bubble surface tension. The total liquid volume ejected by the bubble increases with the surfactant concentration. Surfactant accumulates at the bubble base due to the shrinkage of the cavity bottom and surfactant convection. The resulting reduction in surface tension narrows the region of free surface reversal. Despite this effect, the droplet size increases because Marangoni stress widens the jet and slows the liquid jet interface, delaying droplet detachment. More liquid flows into the droplets, increasing the mass and energy transfer to the resulting spray. A significant increase in the droplet size is also observed with a weak surfactant. This indicates that natural water contamination can substantially alter bubble bursting under critical conditions. Our results may explain the size of the particles emitted by bubble bursting in seawater.
Spiking control of a solenoid valve for high-precision pressure regulation in soft robotics
(IEEE, 2026) Serrano Balbontín, Andrés Joaquín; Tejado Balsera, Inés; Vinagre Jara, Blas Manuel; Aphale, Sumeet S.; San Millán Rodríguez, Andrés; Universidad de Extremadura. Departamento de Ingeniería Eléctrica, Electrónica y Automática; University of Aberdeen. Escocia
Solenoid valves are widely used for pressure regulation in soft pneumatic robots, yet their intrinsic electromechanical nonlinearities, including dead-zone, saturation, and pressure-dependent dynamics, pose significant challenges for control design. Conventional pulse-modulated strategies, such as pulse-width modulation (PWM), often aggravate these effects by ignoring the transient behaviour associated with valve switching. This work introduces a spiking-based control strategy inspired by neuromorphic principles and specifically tailored for pneumatic pressure regulation in soft actuators. The proposed method uses a neuron-like modulator in cascade with a conventional controller to effectively shape the valve input, intrinsically compensate dead-zone and saturation, and improve the linearity of the pressure dynamics through parameter tuning. A complete experimental validation is conducted on a soft pneumatic actuator (SPA) driven by a solenoid valve, benchmarking the proposed approach against standard pulse-modulation techniques. The results show substantial improvements in both static and dynamic linearity, reduced nonlinear distortions, and enhanced consistency in closed-loop pressure control across operating points.