Persona: Urquía Moraleda, Alfonso
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Urquía Moraleda
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Publicación Cyber–physical system modeling with Modelica using message passing communication(Elsevier, 2022-05) Sanz Prat, Víctorino; Urquía Moraleda, AlfonsoModelica 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.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/0000-0002-4245-8103The 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.Publicación ARENALib: A Modelica Library for Discrete-Event System Simulation(2006-01-01) Dormido Bencomo, Sebastián; Sanz Prat, Víctorino; Urquía Moraleda, AlfonsoPublicación FuelCell Lib - A Modelica Library for Modeling of Fuel Cells(Modelica, Gerhard Schmitz (editor), 2005-03-07) Guinea Díaz, Domingo; Sebastián, Dormido; Rubio González, Miguel Ángel; Urquía Moraleda, Alfonso; María González, José LeandroPublicación Simulation practice with Modelica(Universidad Nacional de Educación a Distancia (España). Editorial, 2018-10-01) Urquía Moraleda, Alfonso; Martín Villalba, Carla; Rubio González, Miguel Ángel; Sanz Prat, VíctorinoThis activity book is aimed to provide an introduction to the simulation practice in Engineering using Modelica. To this end, we propose a series of thirteen independent hands-on assignments of increasing complexity. Each assignment contains the description of a system and a mathematical model of the system's behavior. The proposed task often consists in describing this mathematical model in the Modelica language and simulate it. In some assignments, the system's behavior is described as an atomic model, without internal structure. Some other assignments ask to design and implement a model library, and to compose the system model by instantiating and connecting components from this model library. Before start working with this activity book, it is advisable to read its companion theory book: a free e-book entitled "Modeling and simulation in Engineering using Modelica", written by Alfonso Urquía and Carla Martín, and published by Editorial UNED in 2018Publicación Agent-Based Modeling of Traffic Systems Using Modelica(IEEE, 2022-12) Sanz Prat, Víctorino; Urquía Moraleda, AlfonsoA 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.Publicación Object-oriented modelling of virtual-labs for education in chemical process control(Elsevier Science, 2006-01-01) Dormido Bencomo, Sebastián; Martín Villalba, Carla; Urquía Moraleda, AlfonsoPublicación Modelado orientado a objetos de laboratorios virtuales con aplicación a la enseñanza del control de procesos químicos(Actas de las IV Jornadas de Enseñanza a través de Internet/Web de la Ingeniería de Sistemas y Automática, EIWISA2005 (CEA-IFAC), pp.21-26, 2005-01-01) Dormido Bencomo, Sebastián; Martín Villalba, Carla; Urquía Moraleda, AlfonsoPublicación AN APPROACH TO VIRTUAL-LAB IMPLEMENTATION USING MODELICA(proceedings of 3rd International Modelica Conference, Linkoping (Sweden), pp. 161-170, 2006-01-01) Dormido Bencomo, Sebastián; Martín Villalba, Carla; Urquía Moraleda, AlfonsoPublicación An approach to agent-based modeling with Modelica(Elsevier, 2018-04) Bergero, Federico; Sanz Prat, Víctorino; Urquía Moraleda, AlfonsoModelica is a free, general-purpose object-oriented equation-based modeling language. It is mainly designed to describe systems using the physical modeling approach. Our proposal to describe Agent-Based Models (ABMs) in Modelica is discussed in this manuscript. The contribution of the presented work is twofold: firstly, to analyze the conceptual requirements to describe ABMs in Modelica; and secondly, to develop a prototype implementation following the previous analysis. Agents are described using a message passing communication mechanism previously proposed by the authors. Additional extensions to this mechanism are proposed in order to describe agent interactions. The environment, where the agents live, is described as a two-dimensional cellular automaton. A new Modelica library, named ABMLib, developed to support this functionality, is presented. A prototype implementation of the message passing mechanism and ABMLib models has been performed to demonstrate the functionality of the library as a proof-of-concept for this proposal. The library is freely available at www.euclides.dia.uned.es/vsanz.