Persona:
Urquía Moraleda, Alfonso

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0000-0003-0124-3111
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Urquía Moraleda
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Alfonso
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2022 - 20245
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Fecha de inicio: 2020 × search.filters.applied.f.itemFacultad: E.T.S. de Ingeniería Informática ×

Resultados de la búsqueda

Mostrando 1 - 5 de 5
  • Miniatura
    Publicación
    Agent-Based Modeling of Traffic Systems Using Modelica
    (IEEE, 2022-12) Sanz Prat, Víctorino; Urquía Moraleda, Alfonso
    A microsimulation model of traffic described using the Modelica language in combination with the Modelica libraries developed by the authors, ABMLib and CellularAutomataLib2, is presented. Modelica facilitates the description of equation-based models using the physical modeling paradigm, and its combination with the discrete-event and agent-based modeling functionality of the developed libraries constitutes a powerful and versatile tool. The functionality of ABMLib is extended to facilitate the description of individual agent behavior as a combination of equation-based and discrete-event models. In this way, vehicle dynamics and fuel consumption are modeled using equations, while driver behavior is described using an agent-based model. Vehicles move along the road, which is described as a combination of interconnected segments that constitute the environment for the agents. A cellular automaton is used to model the CO2 emissions of vehicles to the environment. A model that represents two consecutive road segments with a semaphore between them is used to illustrate the provided functionality.
  • Miniatura
    Publicación
    Performance uniformity analysis in polymer electrolyte fuel cell using long-term dynamic simulation
    (ELSEVIER, 2024) Culubret, Sergi; Rubio González, Miguel Ángel; Sanchez, D.G.; Urquía Moraleda, Alfonso; https://orcid.org/0000-0002-4245-8103
    The temporal stability and spatial homogeneity of current density are key factors in Polymer Electrolyte Fuel Cell (PEFC) performance and durability. Temporal and spatial variations of relative humidity, fuel concentration, and water droplets in the channels are the principal causes of non-homogeneous current density. A dynamic pseudo-3D model was previously proposed by the authors and has been extended and improved to perform the long-term and intensive simulations of PEFC with low computational cost, which allows to study of the performances homogeneity with different experimental configurations and flow field topologies. The model considers important phenomena in the homogeneity analysis, such as gases and liquid water movement in diffusion layers and flow field, electrochemical reactions, and others. Model validation has been performed using experimental data obtained from a 25 cell with a single serpentine, which has allowed studying the model transient response and spatial representation. The simulations have been used to study the homogeneity and stability of 36 setups of PEFC, varying the rib/channel width ratio, the stoichiometric ratio, and the number of parallel serpentine channels. The results show the importance of a properly flow field design to control gas flow, remove the channels’ liquid water, and keep a homogeneous feeding. The study evaluated a set of channel configurations that show the improved temporal voltage stability and current density spatial homogeneity. The results show the impact of channel gas speed and ratio channel/rib width in liquid droplets removal and the proper fuel spatial distribution; and how configurations with a lesser number of channels in serpentine design require a lower stoichiometric ratio to perform better temporal and spatial uniformity. In the case of the cell configurations simulated, the optimum design was achieved using between 5 and 7 parallel serpentine channels and a channel/rib ratio 3/5.
  • Miniatura
    Publicación
    MSGLib: A Modelica library for message passing communication
    (Elsevier, 2023-07) Sanz Prat, Víctorino; Urquía Moraleda, Alfonso
    MSGLib is a Modelica library designed and developed to support message passing communication and the management of data structures stored in dynamic memory. The functionality of the library facilitates the description of discrete-event models and their combination with other Modelica functionality. MSGLib has been used as a base to develop other Modelica libraries such as DEVSLib, ARENALib and ABMLib. A new version of MSGLib is presented in this manuscript, that includes user documentation, performance optimization and illustrative examples. The library has been developed and tested under Dymola and OpenModelica, and is freely distributed under the LGPL-3.0 license.
  • Miniatura
    Publicación
    Cyber–physical system modeling with Modelica using message passing communication
    (Elsevier, 2022-05) Sanz Prat, Víctorino; Urquía Moraleda, Alfonso
    Modelica is an object-oriented modeling language whose design and features facilitate the description of cyber–physical systems (CPS). Message passing communication (MPC), seen as the transmission of impulses of information between model components, eases the description of the discrete-event parts of CPS models. However, Modelica does not currently supports MPC. Modelica supports an equation-based component connection rationale, where Modelica tools automatically transform component connections into model equations, following a physical modeling approach. The differences between MPC and Modelica connections are analyzed. A proposal for supporting MPC in Modelica is presented, inspired by the coupled PDEVS model communication approach. The presented MPC proposal is based on the definition of structures to manage messages, named buffers, interface ports and communication channels. Also, an implementation of the proposed MPC mechanism in the form of a new free Modelica library, named MSGLib, is presented. MSGLib includes functionality to manage and dynamically store messages, and describe component communications. Two examples, a pick and place system and a robotic arm, are presented to demonstrate the use of the library, and its combination with other Modelica models.
  • Miniatura
    Publicación
    Combining PDEVS and Modelica for describing agent-based models
    (SAGE, 2022-05-08) Sanz Prat, Víctorino; Urquía Moraleda, Alfonso
    Modelica is a general-purpose modeling language mainly designed to facilitate the development, reusability and exchange of models. It represents the state-of-the-art in equation-based modeling of continuous-time systems. Modelica libraries facilitate the description of multi-formalism and multi-domain models. However, the description of agent-based models (ABMs) in Modelica is not currently supported, mainly due to the characteristics of the language and its simulation algorithm. The combination of ABMs with continuous-time equations provides a powerful tool for describing and analyzing complex systems. An approach for describing ABMs using the Modelica language is presented in this manuscript, with the objective of facilitating the combination of ABMs with the rest of Modelica functionality. Agent behavior is described using a process-oriented modeling approach. Agents are described as individual entities that move across a flowchart diagram, that represents the processes that agents undergo. Processes are formally described using the Parallel DEVS formalism, extended to describe the interface with other Modelica models. The environment where agents interact is described as a cellular automaton. This approach has been implemented in a free Modelica library, named ABMLib. Three case studies are discussed to illustrate the modeling functionality of the library and its combination with other models: a basic traffic model, a sheep–wolves predator–prey model and a consumer market model.