285,148 research outputs found

    JAS-mine: A new platform for microsimulation and agent-based modelling

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    We introduce JAS-mine, a new Java-based computational platform that features tools to support the development of large-scale, data-driven, discrete-event simulations. JAS-mine is specifically designed for both agent-based and microsimulation modelling, anticipating a convergence between the two approaches. An embedded relational database management system provides tools for sophisticated input-output communications and data storage, allowing the power of relational databases to be used within an object-oriented framework. The JAS-mine philosophy encourages the separation of distinct concepts, objects and functionalities of the simulation model, and advocates and supports transparency, flexibility and modularity in model design. For instance, JAS-mine allows to store the list of regressors and their estimated coefficients externally to code, making it easy to change the specification of regression models used in the simulation and achieving a complete parallelisation between the tasks of the econometricians and those of the programmers. Moreover, tools for uncertainty analysis and search over the parameter space are also built in

    Analysis and Application of Advanced Control Strategies to a Heating Element Nonlinear Model

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    open4siSustainable control has begun to stimulate research and development in a wide range of industrial communities particularly for systems that demand a high degree of reliability and availability (sustainability) and at the same time characterised by expensive and/or safety critical maintenance work. For heating systems such as HVAC plants, clear conflict exists between ensuring a high degree of availability and reducing costly maintenance times. HVAC systems have highly non-linear dynamics and a stochastic and uncontrollable driving force as input in the form of intake air speed, presenting an interesting challenge for modern control methods. Suitable control methods can provide sustainable maximisation of energy conversion efficiency over wider than normally expected air speeds and temperatures, whilst also giving a degree of “tolerance” to certain faults, providing an important impact on maintenance scheduling, e.g. by capturing the effects of some system faults before they become serious.This paper presents the design of different control strategies applied to a heating element nonlinear model. The description of this heating element was obtained exploiting a data driven and physically meaningful nonlinear continuous time model, which represents a test bed used in passive air conditioning for sustainable housing applications. This model has low complexity while achieving high simulation performance. The physical meaningfulness of the model provides an enhanced insight into the performance and functionality of the system. In return, this information can be used during the system simulation and improved model based and data driven control designs for tight temperature regulation. The main purpose of this study is thus to give several examples of viable and practical designs of control schemes with application to this heating element model. Moreover, extensive simulations and Monte Carlo analysis are the tools for assessing experimentally the main features of the proposed control schemes, in the presence of modelling and measurement errors. These developed control methods are also compared in order to evaluate advantages and drawbacks of the considered solutions. Finally, the exploited simulation tools can serve to highlight the potential application of the proposed control strategies to real air conditioning systems.openTurhan, T.; Simani, S.; Zajic, I.; Gokcen Akkurt, G.Turhan, T.; Simani, Silvio; Zajic, I.; Gokcen Akkurt, G

    An investigation of model-based techniques for automotive electronic system development

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    Over the past decades, the adoption of electronic systems for the manufacturing of automotive vehicles has been exponentially popularized. This growth has been driven by the premium automobile sector where, presently, diverse electronic systems are used. These electronic systems include systems that control the engine, transmission, suspension and handling of a vehicle; air bag and other advanced restraint systems; comfort systems; security systems; entertainment and information (infotainment) systems. In systems terms, automotive embedded electronic systems can now be classified as a System of Systems (SoS). Automotive systems engineering requires a sustainable integration of new methods, development processes, and tools that are specifically adapted to the automotive domain. Model-based design is one potential methodology to carry out design, implement and manage such complex distributed systems, and their integration into one cohesive and reliable SoS to meet the challenges for the automotive industry. This research was conducted to investigate the model-based design of a 4×4 Information System, within an automotive electronic SoS. Two distinct model-based approaches to the development of an automotive electronic system are discussed in this study. The first approach involves the use of the Systems Modelling Language (SysML) based tool ARTiSAN Studio for structural modelling, functional modelling and code generation. The second approach involves the use of the MATLAB based tools Simulink and Stateflow for functional modelling, and code generation. The results show that building the model in SysML by using ARTiSAN Studio provides a clearly structured visualization of the 4×4 Information System from both structural and behavioural viewpoints of the system with relevant objects. SysML model facilitates a more comprehensive understanding of the system than the model built in Simulink/Stateflow. The Simulink/Stateflow model demonstrates its superior performance in producing high quality and better efficiency of C code for the automotive software delivery compared with the model built in ARTiSAN Studio. Furthermore, this Thesis also gets insight into an advanced function development approach based on the real-time simulation and animation for the 4×4 Information System. Finally, the Thesis draws conclusions about how to make use of model-based design for the development of an automotive electronic SoS

    Engineering Enterprise Software Systems with Interactive UML Models and Aspect-Oriented Middleware

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    Large scale enterprise software systems are inherently complex and hard to maintain. To deal with this complexity, current mainstream software engineering practices aim at raising the level of abstraction to visual models described in OMG’s UML modeling language. Current UML tools, however, produce static design diagrams for documentation which quickly become out-of-sync with the software, and thus obsolete. To address this issue, current model-driven software development approaches aim at software automation using generators that translate models into code. However, these solutions don’t have a good answer for dealing with legacy source code and the evolution of existing enterprise software systems. This research investigates an alternative solution by making the process of modeling more interactive with a simulator and integrating simulation with the live software system. Such an approach supports model-driven development at a higher-level of abstraction with models without sacrificing the need to drop into a lower-level with code. Additionally, simulation also supports better evolution since the impact of a change to a particular area of existing software can be better understood using simulated “what-if” scenarios. This project proposes such a solution by developing a web-based UML simulator for modeling use cases and sequence diagrams and integrating the simulator with existing applications using aspect-oriented middleware technology

    The application of software engineering principles towards developing an agent based economy climate model

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    This project attempts to apply the tools of Computer Science to the domain of integrated Economy-Climate modelling. As such the Agent Based Economy Climate (ABEC) model was built, creating an entirely agent based economic subsystem which was paired with an existing system dynamics climate model. Computer Science tools used include software engineering elements such as following a conceptual framework and using rigorous Unified Modelling Language (UML) to aide in model driven development. These conceptual elements were then implemented using design patterns such as an adapter pattern and a modified version of the command pattern to ensure that the developed model is easily expandable, extendable and reusable. The model also leverages a simple evolutionary algorithm in one of the subsections to demonstrate the power these techniques can bear in other domains. The developed simulation model was successfully validated against an established system dynamics model. Results also showed the evoluÂŹtionary algorithm had successfully improved the fitness of the evolved population. However the social aspect of the model was resulting in a level of homogeneity of consumers which was not credible, demonÂŹstrating areas where improvements could be made to the simulation model

    An investigation of model-based techniques for automotive electronic system development

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    Over the past decades, the adoption of electronic systems for the manufacturing of automotive vehicles has been exponentially popularized. This growth has been driven by the premium automobile sector where, presently, diverse electronic systems are used. These electronic systems include systems that control the engine, transmission, suspension and handling of a vehicle; air bag and other advanced restraint systems; comfort systems; security systems; entertainment and information (infotainment) systems. In systems terms, automotive embedded electronic systems can now be classified as a System of Systems (SoS). Automotive systems engineering requires a sustainable integration of new methods, development processes, and tools that are specifically adapted to the automotive domain. Model-based design is one potential methodology to carry out design, implement and manage such complex distributed systems, and their integration into one cohesive and reliable SoS to meet the challenges for the automotive industry. This research was conducted to investigate the model-based design of a 4×4 Information System, within an automotive electronic SoS. Two distinct model-based approaches to the development of an automotive electronic system are discussed in this study. The first approach involves the use of the Systems Modelling Language (SysML) based tool ARTiSAN Studio for structural modelling, functional modelling and code generation. The second approach involves the use of the MATLAB based tools Simulink and Stateflow for functional modelling, and code generation. The results show that building the model in SysML by using ARTiSAN Studio provides a clearly structured visualization of the 4×4 Information System from both structural and behavioural viewpoints of the system with relevant objects. SysML model facilitates a more comprehensive understanding of the system than the model built in Simulink/Stateflow. The Simulink/Stateflow model demonstrates its superior performance in producing high quality and better efficiency of C code for the automotive software delivery compared with the model built in ARTiSAN Studio. Furthermore, this Thesis also gets insight into an advanced function development approach based on the real-time simulation and animation for the 4×4 Information System. Finally, the Thesis draws conclusions about how to make use of model-based design for the development of an automotive electronic SoS.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Model-Driven Development of Control Applications: On Modeling Tools, Simulations and Safety

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    Control systems are required in various industrial applications varying from individual machines to manufacturing plants and enterprises. Software applications have an important role as an implementation technology in such systems, which can be based on Distributed Control System (DCS) or Programmable Control System (PLC) platforms, for example. Control applications are computer programs that, with control system hardware, perform control tasks. Control applications are efficient and flexible by nature; however, their development is a complex task that requires the collaboration of experts and information from various domains of expertise.This thesis studies the use of Model-Driven Development (MDD) techniques in control application development. MDD is a software development methodology in which models are used as primary engineering artefacts and processed with both manual work and automated model transformations. The objective of the thesis is to explore whether or not control application development can benefit from MDD and selected technologies enabled by it. The research methodology followed in the thesis is the constructive approach of design science.To answer the research questions, tools are developed for modeling and developing control applications using UML Automation Profile (UML AP) in a model-driven development process. The modeling approach is developed based on open source tools on Eclipse platform. In the approach, modeling concepts are kept extendable. Models can be processed with model transformation techniques that plug in to the tool. The approach takes into account domain requirements related to, for example, re-use of design. According to assessment of industrial applicability of the approach and tools as part of it, they could be used for developing industrial DCS based control applications.Simulation approaches that can be used in conjunction to model-driven development of control applications are presented and compared. Development of a model-in-the-loop simulation support is rationalized to enable the use of simulations early while taking into account the special characteristics of the domain. A simulator integration is developed that transforms UML AP control application models to Modelica Modeling Language (ModelicaML) models, thus enabling closed-loop simulations with ModelicaML models of plants to be controlled. The simulation approach is applied successfully in simulations of machinery applications and process industry processes.Model-driven development of safety applications, which are parts of safety systems, would require taking into account safety standard requirements related to modeling techniques and documentation, for example. Related to this aspect, the thesis focuses on extending the information content of models with aspects that are required for safety applications. The modeling of hazards and their associated risks is supported with fault tree notation. The risk and hazard information is integrated into the development process in order to improve traceability. Automated functions enable generating documentation and performing consistency checks related to the use of standard solutions, for example. When applicable, techniques and notations, such as logic diagrams, have been chosen so that they are intuitive to developers but also comply with recommendations of safety standards

    Model Based Design of the Conference System

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    Tato diplomovĂĄ prĂĄce se zabĂœvĂĄ problematikou modelem ƙízenĂ©ho nĂĄvrhu a aplikace simulacĂ­ v nĂĄvrhu systĂ©mĆŻ. V rĂĄmci uvedenĂ­ do problematiky prĂĄce diskutuje historii procesu vĂœvoje SW a nastiƈuje jeho aktuĂĄlnĂ­ stav. CĂ­lem prĂĄce je demonstrovat modelem ƙízenĂœ nĂĄvrh na pƙípadovĂ© studii konferenčnĂ­ho systĂ©mu. KonkrĂ©tně zde budou pƙedstaveny formalismy DEVS a OOPN  společně s experimentĂĄlnĂ­mi nĂĄstroji PNtalk a SmallDEVS, kterĂ© umoĆŸĆˆujĂ­ prĂĄci s těmito formalismy. VĂœslednĂœ model konferenčnĂ­ho systĂ©mu bude nasazen jako součást webovĂ© aplikace implementovanĂ© pomocĂ­ frameworku Seaside v prostƙedĂ­ Squeak.This thesis deals with the topic of  model-based design and application of simulation in system design. In the introduction, the thesis discusses the history of software development process and outlines the current status. The aim is to demonstrate a model-driven design on a case study of conference system. There will be presented formalisms of DEVS and OOPN  together with experimental tools PNtalk and SmallDEVS that allow to work with these formalisms. The resulting model of conference system will be deployed as part of a web application using a framework Seaside in the Squeak environment.

    A dynamics-driven approach to precision machines design for micro-manufacturing and its implementation perspectives

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    Precision machines are essential elements in fabricating high quality micro products or micro features and directly affect the machining accuracy, repeatability and efficiency. There are a number of literatures on the design of industrial machine elements and a couple of precision machines commercially available. However, few researchers have systematically addressed the design of precision machines from the dynamics point of view. In this paper, the design issues of precision machines are presented with particular emphasis on the dynamics aspects as the major factors affecting the performance of the precision machines and machining processes. This paper begins with a brief review of the design principles of precision machines with emphasis on machining dynamics. Then design processes of precision machines are discussed, and followed by a practical modelling and simulation approaches. Two case studies are provided including the design and analysis of a fast tool servo system and a 5-axis bench-top micro-milling machine respectively. The design and analysis used in the two case studies are formulated based on the design methodology and guidelines

    Model-driven design, simulation and implementation of service compositions in COSMO

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    The success of software development projects to a large extent depends on the quality of the models that are produced in the development process, which in turn depends on the conceptual and practical support that is available for modelling, design and analysis. This paper focuses on model-driven support for service-oriented software development. In particular, it addresses how services and compositions of services can be designed, simulated and implemented. The support presented is part of a larger framework, called COSMO (COnceptual Service MOdelling). Whereas in previous work we reported on the conceptual support provided by COSMO, in this paper we proceed with a discussion of the practical support that has been developed. We show how reference models (model types) and guidelines (design steps) can be iteratively applied to design service compositions at a platform independent level and discuss what tool support is available for the design and analysis during this phase. Next, we present some techniques to transform a platform independent service composition model to an implementation in terms of BPEL and WSDL. We use the mediation scenario of the SWS challenge (concerning the establishment of a purchase order between two companies) to illustrate our application of the COSMO framework
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