Persona: Urquía Moraleda, Alfonso
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Urquía Moraleda
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Alfonso
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Publicación 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.Publicación Extending Modelica Support for Parallel DEVS and Cellular Automata Modeling and Simulation(Nova Science Publishers, 2017-09) Sanz Prat, Víctorino; Urquía Moraleda, AlfonsoModelica is a general-purpose modeling language designed to describe mathematical models of physical systems using the object-oriented modeling approach. Since Modelica includes language constructs to manage discrete events, multiple discrete event modeling formalisms are supported, in the form of libraries of models. The authors have designed and developed the DEVSLib and CellularAutomataLib2 Modelica libraries to facilitate the description of Parallel DEVS (P-DEVS) and Cellular Automata (CA) models. P-DEVS can serve as underlying mathematical formalism to describe the discrete-event part of a hybrid model. The DEVSLib library has been used to develop the SIMANLib and ARENALib libraries that reproduce some functionality of the SIMAN language and the Arena simulation environment. On the other hand, the integration of CA models in Modelica is an interesting and promising topic. CA can be applied to the description of models that depend on the spatial coordinates and their simulation algorithm is conceptually simple. CellularAutomataLib2 facilitates the combination of CA models with the object-oriented modeling approach supported by Modelica. The design and functionality of these libraries and their integration with other Modelica models is discussed in this manuscript. Examples of a random delay P-DEVS model, a bank teller, a pendulum clock, an opto-electrical system, a tank level control system, a soaking-pit furnace and a SIR epidemic spread model are included to illustrate their functionality and use. These libraries are freely distributed at http://www.euclides.dia.uned.es.Publicación ARENALib: A Modelica Library for Discrete-Event System Simulation(2006-01-01) Dormido Bencomo, Sebastián; Sanz Prat, Víctorino; Urquía Moraleda, AlfonsoPublicación MSGLib: A Modelica library for message passing communication(Elsevier, 2023-07) Sanz Prat, Víctorino; Urquía Moraleda, AlfonsoMSGLib 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.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 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 Combining PDEVS and Modelica for describing agent-based models(SAGE, 2022-05-08) Sanz Prat, Víctorino; Urquía Moraleda, AlfonsoModelica 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.Publicación 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 2018