Artículos, conferencias, monografías
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Esta colección está formada por artículos, conferencias, comunicaciones y otras publicaciones elaborados por miembros de la Universitat Politècnica de València.
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- PublicaciónA mathematical model with uncertainty quantification for allelopathy with applications to real-world data(Springer-Verlag, 2024-04) Bevia-Escrig, Vicente-José; Cortés López, Juan Carlos; Moscardó-García, Ana; Perez Diukina, Cristina; Villanueva Micó, Rafael Jacinto; Departamento de Matemática Aplicada; Facultad de Administración y Dirección de Empresas; Instituto Universitario de Matemática Multidisciplinar; Escuela Técnica Superior de Ingeniería de Telecomunicación; Ministerio de Universidades; AGENCIA ESTATAL DE INVESTIGACION; Universitat Politècnica de València[EN] We revisit a deterministic model for studying the dynamics of allelopathy. The model is formulated in terms of a non-homogeneous linear system of diferential equations whose forcing or source term is a piecewise constant function (square wave). To account for the inherent uncertainties present in this natural phenomenon, we reformulate the model as a system of random diferential equations where all model parameters and the initial condition are assumed to be random variables, while the forcing term is a stochastic process. Taking extensive advantage of the so-called Random Variable Transformation (RVT) method, we obtain the solution of the randomized model by providing explicit expressions of the frst probability density function of the solution under very general assumptions on the model data. We also determine the joint probability density function of the non-trivial equilibrium point, which is a random vector. If the source term is a time-dependent stochastic process, the RVT method might not be applicable since no explicit solution of the model is available. We then show an alternative approach to overcome this drawback by applying the Liouville¿Gibbs partial diferential equation. All the theoretical fndings are illustrated through several examples, including the application of the randomized model to real-world data on alkaloid contents from leaching thornapple seed.
- PublicaciónStudy of the filtration efficiency of radon progeny in facial masks(Elsevier, 2024-10) Martínez Ferri, Javier Enrique; Juste Vidal, Belen Jeanne; Verdú Martín, Gumersindo Jesús; Departamento de Matemática Aplicada; Instituto Universitario de Seguridad Industrial, Radiofísica y Medioambiental; Escuela Técnica Superior de Ingeniería de Telecomunicación; Departamento de Ingeniería Química y Nuclear; Escuela Técnica Superior de Ingeniería Industrial; Universitat Politècnica de València[EN] Radon exposure is the second-leading environmental cause of lung cancer, therefore finding ways to reduce the radon inhalation dose is a priority objective. Inhalation dose is calculated considering two contributions, the radon gas on the one hand and its progeny on the other. This paper studies the effectiveness of face masks (surgical masks, FFP2 and FFP3) to reduce the contribution of radon descendants that pass into the respiratory tract and thus reduce associated inhalation doses. To analyze the radon filtering potential of these masks, a continuous radon monitor has been used to estimate the radon concentration and the Potential Alpha Energy Concentration with and without facial masks. The data registered by this monitor, together with an error minimization algorithm developed in Matlab®, allow the Equilibrium Equivalent Concentration to be calculated. These results make it possible to compare the inhalation doses received by a person not wearing or wearing different types of masks, obtaining a dose reduction of 64% for surgical masks compared to the study without mask, a reduction of 71% for FFP2 and 72% for FFP3 masks.
- PublicaciónDesigning Decentralized Multi-Variable Robust Controllers: A Multi-Objective Approach Considering Nearly Optimal Solutions(MDPI AG, 2024-07) Pajares Ferrando, Alberto; Blasco Ferragud, Francesc Xavier; Herrero Durá, Juan Manuel; Sanchis Saez, Javier; Simarro Fernández, Raúl; Instituto Universitario de Automática e Informática Industrial; Escuela Técnica Superior de Ingeniería Aeroespacial y Diseño Industrial; Departamento de Ingeniería de Sistemas y Automática; Escuela Técnica Superior de Ingeniería Industrial; GENERALITAT VALENCIANA; AGENCIA ESTATAL DE INVESTIGACION; European Regional Development Fund[EN] This article presents a new methodology for designing a robust, decentralized control structure that considers stochastic parametric uncertainty and uses a multi-objective approach. This design tunes the loop pairing and controller to be implemented. The proposed approach obtains the optimal and nearly optimal controllers relevant to the nominal scenario. Once obtained, the robustness of these solutions is analyzed. This methodology is compared with a traditional approach for selecting the most robust control pairings. The traditional approach obtains lightly robust controllers, i.e., the most robust controllers with an acceptable performance for the nominal scenario, and it obtains trade-offs between robustness and nominal performance. However, the traditional approach has a high computational cost because it is necessary to consider uncertainty in the optimization stage. The proposed approach mathematically guarantees the acquisition of at least one neighbor controller for each existing lightly robust controller. Therefore, this approach obtains solutions similar to lightly robust solutions with a significantly lower computational cost. Furthermore, the proposed approach provides the designer with more diversity and interesting solutions that are not lightly robust. The different approaches are compared using an example of a multi-variable process with two alternative control structures. The results show the usefulness of the proposed methodology.
- PublicaciónExploiting neural networks Bit-level redundancy to mitigate the impact of faults at inference(Springer-Verlag, 2025-01) Catalán Gallach, Izan; Flich Cardo, José; Hernández Luz, Carles; Escuela Técnica Superior de Ingeniería Informática; Grupo de Arquitecturas Paralelas; Departamento de Informática de Sistemas y Computadores; Desconocido; GENERALITAT VALENCIANA; Agencia Estatal de Investigación; UNIVERSIDAD POLITECNICA DE VALENCIA[EN] Neural networks are widely used in critical environments such as healthcare, autonomous vehicles, or video surveillance. To ensure the safety of the systems that rely on their functionality, it is essential to validate their correct behaviour in the presence of faults. This paper studies the behaviour of state-of-the-art neural network models with fault injection in their weights. For this purpose, we analyse the sensitivity of these models and identify the impact of bit flips on their accuracy. To mitigate the effects of faults, we introduce two mechanisms that leverage bit-level redundancy for protection. The first mechanism, Fixed Protection, safeguards consecutive sets of bits, while the second, Variable Protection, targets non-consecutive bits. Our findings demonstrate that, on average, random bit flip faults cause the accuracy of the original models to drop by 1.3% to over 3%. However, with our protection mechanisms in place, accuracy reductions are significantly minimised, ranging from only 0.0001% to 0.4%.
- PublicaciónReprocessed fuels in a PWR SMR based on NuScale(Elsevier, 2025-05) Fernandes, Samuel; Chaves, Lucas; Melo, Joao P. Cunha; Corrêa, Karytha M. S.; Gonçalves, Natalia; Barrachina Celda, Teresa María; Miró Herrero, Rafael; Pereira, Claubia; Instituto Universitario de Seguridad Industrial, Radiofísica y Medioambiental; Departamento de Ingeniería Química y Nuclear; Escuela Técnica Superior de Ingeniería Industrial; AGENCIA ESTATAL DE INVESTIGACION; Fundação de Amparo à Pesquisa do Estado de Minas Gerais; Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior, Brasil; Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brasil[EN] This work evaluated reprocessed fuels in a core model based on a NuScale, a PWR Small Modular Reactor (SMR). With a model starting from the equilibrium core, this work suggests the replacement of fresh UO2 fuel with reprocessed fuels. It evaluated two types of reprocessed fuels: spiked with thorium and spiked with depleted U (0.2%). The main aim is to analyze the core burnup process with reprocessed fuels inserted in some assemblies and analyze the depleted spent fuel composition, multiplication factor during burnup, power distribution, leakage, and core activity. The core was modeled and simulated using the MC code SERPENT 2.2.1. As expected, the activity values for the models with reprocessed fuels are higher. The model with thorium has the highest activity and leakage. The keff s during burnup are higher for reprocessed fuels, which could lead to an extension of the burnup. The change in power distribution is minimal. It is necessary to advance the evaluation of reprocessed fuels to ensure a better destination for radioactive waste, as well as a better destination for depleted uranium. This material has shown promising results in reprocessed fuel analysis.