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作者： Soto Afonso, Juan Calixto LAPPEENRANTA UNIVERSITY OF TECHNOLOGY

学位级别：硕士

The computational advances of the modelling and simulation tools in Chemical Engineering open up the possibility of studying in a general, robust and efficient way (avoiding the peculiarities and restrictions of analytical methods) the possible improvement of certain non- linear chemical systems switching from the steady state mode of operation to a dynamic one with forced oscillations that enable the emergence of complex behavior in these systems. In this work, we propose to apply this idea to a case of interest in the industry, the single and multicomponent solvent extraction of metals in mixer-settlers, one of the main hydrometallurgical processes. To do so, following the latest trends, the process is modelled mathematically applying the modern object-oriented modelling and simulation paradigm, using the Simscape equation based language within the Simulink environment, which allows solving the complex DAE systems that arise from dynamic models. The fundamental and complex problem of determining the optimal value of the parameters of the inputs to oscillate (amplitude and frequency of the sine wave oscillations of the flowrates of the aqueous and organic streams) is addressed by a Global Sensitivity Analysis (GSA), through statistical sampling with Monte Carlo simulations that explore the design space of the problem. For the discussion of the results, obtained by means of simulation, a comparison between the steady state and the dynamic oscillatory modes of operation is carried out. In the case of the single component study, the variable to be optimized is shrinkage of metal, while in the multicomponent case, it is necessary to study together the productivity and purity of the process in the whole range of operation.

关键词： Nonlinear chemical dynamics Complexity Forced periodic oscillations Solvent extraction object-oriented simulation DAE system Simscape-Simulink Design Space Exploration Global Sensitivity Analysis

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object-oriented Modeling and simulation of a TRIGA reactor plant with Dymola 71

Object-Oriented Modeling and simulation of a TRIGA reactor p...

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71st Conference of the Italian-Thermal-Machines-Engineering-Association (ATI)

作者： Boarin, Sara Cammi, Antonio Ponciroli, Roberto Chiesa, Davide Previtali, Ezio Sisti, Monica Magrotti, Giovanni Prata, Michele Salvini, Andrea Politecn Milan Via La Masa 34 I-20156 Milan Italy Argonne Natl Lab 9700 South Cass Ave Argonne IL 60439 USA Univ Milano Bicocca Phys Dept G Occhialini Piazza Ateneo Nuovo I-20126 Milan Italy INFN Sect Piazza Ateneo Nuovo I-20126 Milan Italy Univ Pavia LENA Via Gaspare Aselli 41 I-27100 Pavia Italy

This work presents the modeling and simulation of a TRIGA-Mark II pool-type reactor with Zirchonium-Hydryde and Uranium fuel immersed in light water, with Modelica object-oriented language, in Dymola simulation environment. The model encompasses the integrated plant system including the reactor pool and cooling circuits. The reactor pool plays a fundamental role in the system dynamics, through a thermal feedback effect on the reactor core neutronics. The pool model is tested against three experimental transients: simulation results are in good accordance with experimental data and provide useful information about the inertial effect of the water inventory on the reactor cooling. (C) 2016 The Authors. Published by Elsevier Ltd.

关键词： Reactor dynamics reactor pool object-oriented simulation Modelica TRIGA

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object-oriented Modeling and simulation of a TRIGA reactor plant with Dymola

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Energy Procedia 2016年 101卷 42-49页

作者： Sara Boarin Antonio Cammi Roberto Ponciroli Davide Chiesa Ezio Previtali Monica Sisti Giovanni Magrotti Michele Prata Andrea Salvini Politecnico di Milano via La Masa 34 20156 Milan Italy Argonne National Laboratory 9700 South Cass Avenue Argonne IL 60439 University of Milano-Bicocca Physics Department “G. Occhialini” and INFN Section Piazza dell’Ateneo Nuovo 20126 Milan Italy University of Pavia Applied Nuclear Energy Laboratory (L.E.N.A.) Via Gaspare Aselli 41 27100 Pavia Italy

关键词： Reactor dynamics reactor pool object-oriented simulation Modelica TRIGA

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object oriented simulation of Agent Based FlexibleManufacturing System with Dynamic Routing and Scheduling

Object Oriented Simulation of Agent Based FlexibleManufactur...

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作者： Ghosal, Subhabrata Ohio University

学位级别：master

Flexible Manufacturing Systems (FMS) have long been aproposed solution towards effective automated manufacturing withimproved cost, time, efficiency and resource flexibilities. The twomajor factors towards the development of an efficient FMS aremachine flexibility (i.e. the systems latitude towards changedproduct type and order of operations), and routing flexibility(i.e. the ability to use different machines or group of machines toperform similar operations on a manufacturing part). These twofactors can be addressed by selecting an optimized schedule ofmanufactured products. In this research, the problem of selectingan optimized schedule and process plan is addressed through machineactivity based dynamic process plan generation using priority-basedprocess planning network and simulation of the selected processplans to make an assessment of their performance. A market orienteddistributed agent based prototype architecture of FMS has beendeveloped using the Java Agent Development Environment (JADE), aJava based middleware for multi- agent systems, capable ofexecuting manufacturing tasks disintegrated into modular sub-tasksthrough intelligent agents. This agent-based model communicateswith the simulation module through object oriented data *** is conducted on the various process plans generated outof the process planning network for multiple parts produced by theprocess planning network agent through java interface. Thesimulation model of the FMS has been implemented in AnyLogic. Theprocess simulation agent executes simulation using process plandata to record statistics of performance and measure effectivenessof the process plans. The performance of this system is comparedwith results obtained from discrete event simulation of processplans generated through feature based heuristics on a monolithicFMS. A considerable improvement in performance isobserved

关键词： Artificial Intelligence Industrial Engineering Agent-based programming object-oriented simulation AnyLogic JADE Flexible Manufacturing System Process Planning

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A discrete event simulator to implement deep reinforcement learning for the dynamic flexible job shop scheduling problem

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simulation MODELLING PRACTICE AND THEORY 2024年 134卷

作者： Tiacci, Lorenzo Rossi, Andrea Univ Perugia Dipartimento Ingn Via Duranti 93 I-06125 Perugia Italy

The job shop scheduling problem, which involves the routing and sequencing of jobs in a job shop context, is a relevant subject in industrial engineering. Approaches based on Deep Reinforcement Learning (DRL) are very promising for dealing with the variability of real working conditions due to dynamic events such as the arrival of new jobs and machine failures. Discrete Event simulation (DES) is essential for training and testing DRL approaches, which are based on the interaction of an intelligent agent and the production system. Nonetheless, there are numerous papers in the literature in which DRL techniques, developed to solve the Dynamic Flexible Job Shop Problem (DFJSP), have been implemented and evaluated in the absence of a simulation environment. In the paper, the limitations of these techniques are highlighted, and a numerical experiment that demonstrates their ineffectiveness is presented. Furthermore, in order to provide the scientific community with a simulation tool designed to be used in conjunction with DRL techniques, an agent-based discrete event simulator is also presented.

关键词： Scheduling Job shop Deep reinforcement learning object-oriented simulation

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object-oriented simulation of coral competition in a coral reef community

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ECOLOGICAL MODELLING 2012年 245卷 111-120页

作者： Tam, Tze-wai Ang, Put O. Chinese Univ Hong Kong Sch Life Sci Biol Programme Shatin Hong Kong Peoples R China

A 3-dimensional individual-based model, the ReefModel, was developed to simulate the dynamical structure of coral reef community using object-oriented techniques and Smalltalk/V language. Interactions among six functional groups of reef organisms: tabular coral, foliaceous coral, massive coral, macroalga, corallivorous gastropod and herbivorous fish were examined. Results from the simulation of interaction among the three coral groups are presented here. The behaviours of the coral groups were described with simple mechanistic rules that were derived from their general behaviours (e.g. growing habits, competitive mechanisms) observed in natural coral reef communities. All corals were allowed to grow in a 3-dimensional spatial environment. The model was implemented to explore the competitive mechanisms governing coral community structure. simulation results suggest that a fast-growing habit with overtopping competitive mechanism is probably the most effective strategy for corals to gain spatial dominance in a coral community under stable environmental conditions. In addition, multimodality exists in the final states of individual coral group as a result of small random spatial events that occurred during the early stages of interactions among the corals in the community. This suggests that alternative stable states may exist in a coral community as a result of inter-specific coral competition. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Coral reef model object-oriented simulation Alternative stable states Coral competition 3-Dimensional individual-based model

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object-oriented simulation of an Endex reactor for separation of carbon dioxide from flue emissions

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COMPUTERS & CHEMICAL ENGINEERING 2012年 40卷 213-222页

作者： Plouffe, P. McEvoy, J. Gamage Ball, R. Anthony, E. J. Australian Natl Univ Inst Math Sci Canberra ACT Australia Univ Ottawa Fac Engn Ottawa ON K1N 6N5 Canada

Endex calcium looping is a novel early-stage technology for separating CO2 from flue gases that shows great potential for reducing the high cost of the regeneration step because the calcination temperature is significantly lower. In this work an Endex calcium looping system is modelled as a train of continuous stirred tank reactor (CSTR) elements mass-coupled in series and thermally coupled in parallel. A novel simulator was developed that incorporates object-oriented design to describe the Endex reactor and its components, and used to study the effects of varying the most important design and operating parameters. From a reactor design point of view, varying the heat transfer coefficient and the sorbent flow rate amounts to testing the classic tradeoff between capital and running costs: we may choose between higher capital costs (larger heat transfer coefficient) and lower running costs (low sorbent flow rate) or vice versa, for similar scrubbing and regeneration efficiencies. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Endex Calcium looping Carbon capture object-oriented simulation

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object-oriented event-graph modeling formalism to simulate manufacturing systems in the Industry 4.0 era

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simulation MODELLING PRACTICE AND THEORY 2020年 99卷

作者： Tiacci, Lorenzo Univ Perugia Dipartimento Ingn Via Duranti 93 I-06125 Perugia Italy

In the event-based modeling formalism a system is modeled by defining the changes that occur at event times and the system dynamics can be described using an 'Event Graph'. An event graph model is a network of event nodes describing the events that take place in the system and the relationships among these events. In the paper we extend the Event Graph framework by proposing an event-graph modeling formalism suitable to represent discrete event simulation models developed through the object-oriented approach, named object-oriented Event Graph (OOEG). The importance of object-oriented simulation is recently growing under the Industry 4.0 paradigm, in which optimization via simulation, real-time simulation, automatic decisions systems based on simulation, on line scenario analysis play a relevant role. The OOEG representation provides the same compactness of the EG representation. The advantage of the OOEG representation is that allows supporting a modelling methodology where systems are described by linking components analogously as the system components are linked, and the dynamic of the systems can be visualized in terms of interactions between objects, which have their physical correspondence in the real world.

关键词： Discrete event simulation Manufacturing systems object-oriented simulation Industry 4.0

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Event and object oriented simulation to fast evaluate operational objectives of mixed model assembly lines problems

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simulation MODELLING PRACTICE AND THEORY 2012年 24卷 35-48页

作者： Tiacci, Lorenzo Univ Perugia Dipartimento Ingn Ind I-06125 Perugia Italy

In this paper an event and object oriented simulator for assembly lines is presented. The tool, developed in Java, is capable to simulate mixed model assembly lines, with stochastic task times, parallel stations, fixed scheduling sequences, and buffers within workstations. The simulator is a flexible supporting tool in finding solution of the mixed model assembly line balancing problem (and the optimal sequencing and buffer allocation problems associated to it). It is capable to immediately calculate the throughput of a complex line, by simply receiving as inputs three arrays representing: the task times durations, the line configuration (number of workcentres, of buffers within them, of parallel workstations in each workcentre, of tasks assigned to each workcentre), and the sequence of models entering the line. Its fastness and flexibility allow its utilization in those algorithms and procedures where the evaluation of a fitness function (which includes the throughput as performance indicator) has to be performed several times. It allows overcoming the limit of using others measures of throughput, presented in literature, that are poorly correlated to its real value when the complexity of the line increases. The simulator is an expandable tool;in its current version provides the possibility to simulate both straight and U-shaped lines, and to generate both random and fixed sequences of models entering the line. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Event-oriented simulation object-oriented simulation Line balancing Mixed model Sequencing Buffer allocation U-shaped lines

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A simulation modeling framework for multiple-aisle automated storage and retrieval systems

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JOURNAL OF INTELLIGENT MANUFACTURING 2014年第1期25卷 193-207页

作者： Gagliardi, Jean-Philippe Renaud, Jacques Ruiz, Angel Univ Laval Fac Sci Adm Interuniv Res Ctr Enterprise Networks Logist & Tr Quebec City PQ G1V 0A6 Canada

This paper presents a simulation model framework for unit-load automated storage and retrieval systems (AS/RS) able to cope with most of the features found in industrial settings like, for example, multiple aisles, non aisle-captive cranes or double-deep unit-load AS/RS. Although these features characterize most of the industrial applications, they have been simply neglected by most of the previously published research oriented papers, which explains at least partially the low impact of the research output in practice. To help mitigating this drawback, this paper first presents an up-to-date chronological literature survey, which includes works that use any form of simulation in the modeling process. It then proposes an object-oriented simulation Model for unit-load AS/RS developed with a purely generic mindset. In this model, the physical design decisions are separated from the operational decisions, which makes it possible, first, to obtain a better understanding of AS/RS dynamics and, second, to increase the model's flexibility and generality, thus allowing many interesting scenarios to be represented. In particular, the simulation modeling framework has been used to develop a simulator and to conduct a preliminary study on a multi-aisle AS/RS.

关键词： Multiple-aisle automated storage and retrieval systems Unit-load End-of-aisle Discrete-event simulation object-oriented simulation Warehousing

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