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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Modeling Transmission Dynamics Of Tuberculosis Including Various Latent Periods

Atkins, Tracy 01 January 2008 (has links)
The systems of equations created by Blower et al. (1995) and Jia et al. (2007) designed to model the dynamics of Tuberculosis are solved using the computer software SIMULINK. The results are first employed to examine the intrinsic transmission dynamics of the disease through two models developed by Blower et al. (1995). The "simple transmission model" was used primarily to give insight to the behavior of the susceptible, latent, and infectious groups of individuals. Then, we consider a more detailed transmission model which includes several additional factors. This model captures the dynamics of not only the susceptible, latent and infectious groups but also the non-infectious cases and the recovered cases. Using the SIMULINK results, it can be shown that the intrinsic dynamics of the disease contribute to the rise and decline of the disease seen in historical accounts. Next, the simulation results are used to study the equilibrium points of the disease which can be obtained by varying the parameters and therefore changing the value for the basic reproduction ratio (R0 ). Our model uses the system of equations developed by Jia et al. (2007). The SIMULINK results are used to visually confirm the hypothesis proposed by Jia et al. (2007) that the equilibrium behavior of the system when R0 > 1 is globally asymptotically stable.
32

Modelling and improvement of 2-Speed Smoothing System

Nilsson, Oskar January 2021 (has links)
A skid steer loader is a machine used in construction for multiple tasks. Its small size and versatility makesit a use-full addition to any work site. The machine is driven by a combustion engine that in turn powers ahydraulic pump. This hydraulic fluid from the pump is then directed to either motor to propel the vehicle. Twospeed motors are used to allow high-speed operation. A problem present in the current design of the hydraulicsystem for a skid steer loader is its tendency to jerk when shifting speed at low temperatures. In an effort toidentify potential problems and rectify those, two models will be constructed in Simulink. One is a model ofthe whole system, where the pump and both motors are included as well as the machine itself. The other modelis designed to predict the system behaviour of one motor and a pump in a flywheel test rig. Also auxiliarycomponents are included in the models, including the two-speed shifting valve and pressure release valves. Bothmodels will predict the system behaviour from a set of input variables, including temperature, oil viscosity andgeometrical parameters. Improvements to the design where identified by analysing the simulation data. It wasfound that system performance could be enhanced by switching to an alternative notch shape of the two-speedshifting valve.
33

Design and Modularization of a Hybrid Vehicle Control System

Fella Pellegrino, Augustino January 2021 (has links)
The complexity of automotive software has increased dramatically in recent years. New technological advances as well as increasing market competitiveness create a high cost-pressure environment. This thesis seeks to apply established modular principles to a Simulink Model to increase information hiding to improve the maintainability of controls software. A Hybrid Supervisory Controller (HSC) model, developed as part of the McMaster EcoCAR Competition, is used throughout this thesis. The software design process followed during the HSC model development is detailed, as well as providing an example of the application of the Simulink Module Tool, a Simulink add-on developed by Jaskolka et. al. The HSC System decomposition was restructured based on an analysis of the likely changes to the vehicle software, as well the system secrets contained within the model. This thesis also presents an analysis of the original and modular system decompositions, comparing several common software indicators of information hiding, coupling, cohesion, complexity, and testability. The modular decomposition led to a significant improvement in information hiding, both in system changeability and internal implementation. Likely changes to the system propagate to fewer modules and components within the new decomposition, with hardware data separated from behavioral algorithms, and all modules grouped based on shared secrets. The redistribution of algorithms based on separation of concern also led to improvements in coupling, cohesion, and interface complexity. The resulting software design process and modular system decomposition provides a framework for future EcoCAR students to focus on correct design and implementation of hybrid vehicle software. The benefits provided by the application of the Simulink Module Tool also contributes additional data and supporting evidence to the improvements that can be realized within Simulink Models by introducing the concepts of information hiding and modularity. / Thesis / Master of Applied Science (MASc) / The complexity of automotive software has increased dramatically in recent years. New technological advances as well as increasing market competitiveness create a high cost-pressure environment. As a result, improving the development of automotive software and its maintainability has become an increasingly critical issue to solve. This thesis uses a Hybrid Vehicle Controller Model developed within MATLAB Simulink to investigate the possible improvements that can be made to software modularity. The system decomposition is modified using the Simulink Module Tool, and is analyzed regarding improvements to information hiding, interface complexity, and specifically minimizing change propagation. The modular improvements made to the Simulink Model resulted in significant improvements in system changeability and information hiding, providing a useful framework for future EcoCAR students.
34

An Automated Controller Design Methodology for Six Degree-of-Freedom Aircraft Models

Dierker, Dominic J. January 2017 (has links)
No description available.
35

On-the-Modelling of a Green Hydrogen System : Electrolyzer- and Fuel Cell Modeling

George, Ludwig January 2022 (has links)
With the ongoing increasing focus on the development of intermittent renewable sources, there is a clear need for energy storage solutions that can handle large fluctuations in power and store large amounts of energy. Hydrogen i seen as a candidate as a possible energy carrier for this purpose, and many hydrogen projects have been seen occurring over the world. In order to enable further development of hydrogen systems for the production and utilization of hydrogen fuel, modeling can be performed to investigate the performance, feasibility, and responses of these systems. There is, however, a need for further development of electrolyzer models for production, and fuel cell models for the utilization of hydrogen fuels. The goal of this thesis is to further develop models of electrolyzers and fuel cells with an electrical engineering perspective to be used in further research. This is done by reviewing relevant research related to these topics and narrowing down the findings into comprehensive, simple, and dynamic models in MATLAB/Simulink. These models are described in this thesis, along with the obtained static and dynamic results of the hydrogen production and utilization systems. The models include the option to parameterize to the steady-state data to replicate the static behavior and specify dynamics in terms of capacitive effects and reactant pressure controls for the fuel cell. The Simulink models created can be utilized to further develop various other system components.
36

Diseño e implementación del simulador de balance de carga de bateríad del satélite SAOCOM, desarrollado mediante el empleo de Técnicas de Computación Científica

Villamil, Carlos Ramiro 15 April 2015 (has links)
La presente tesis tiene como objetivo principal el diseño e implementación de un simulador del sistema de potencia del satélite SAOCOM 1-A, que la empresa INVAP S.E. está desarrollando. Para el diseño de este simulador, se realizó un estudio minucioso de cada una de las partes que lo componen, así como también se estudiaron diferentes implementaciones de simuladores de potencia utilizados en el desarrollo de satélites previos, prestando especial atención a las diferencias encontradas entre los datos simulados y los datos obtenidos por telemetría directa del satélite. Mediante el empleo de técnicas de Computación Científica se desarrollaron los algoritmos que luego se implementaron en Simulink de Matlab, programa particularmente apto para el desarrollo de este tipo de simulaciones. Este simulador permite obtener información detallada de todo el sistema de potencia: tensión del BUS, estado de carga de las baterías, presión interna de las celdas, nivel de energía generada por los paneles solares, incidencia del sol sobre paneles, etc. Toda la información obtenida del simulador se utiliza para verificar que ninguno de los parámetros se vaya más allá de los niveles permitidos y en caso de ser así se puede rediseñar alguna de las partes que componen al sistema o bien determinar cuales serán los perfiles de actividad que, con esta configuración, el satélite no podrá soportar. En síntesis, a través de la presente investigación se logró desarrollar una herramienta computacional de análisis que brinda la posibilidad de estudiar en detalle el comportamiento de cada uno de los parámetros que intervienen en el sistema de potencia de un satélite, brindando información crítica en una etapa temprana del diseño del mismo.
37

Microgrid Modeling, Planning and Operation

Su, Wencong 10 December 2009 (has links)
As distributed generations and renewable energy are becoming the fastest growing segment of the energy industry, the technical issues and environmental impacts have to be studied and understood. The large number of small-scale Microgrid components with their own characteristics is a big challenge for Microgrid modeling, simulation, planning and operation. The major goal of this thesis is to build a library of various Microgrid components. First of all, the thesis is going to present a detailed description of Microgrid models with moderate complexity. Next, it will present the modeling of loads, utility grid and transmission lines. Then, the paper will discuss the distributed generation models that have been developed in Matlab/Simulink including Diesel Engine, Fuel Cell, Micro Gas Turbine, Wind Turbine, Photovoltaic Cell, along with the detailed modeling of short-term storage (Battery, Pumped Hydro Storage, Flywheel, and Supercapacitor). In addition to steady-state study, the thesis will also discuss the hybrid sample systems that are built to investigate their transient responses. To enhance the simulation performance, some improvements on modeling and simulation will be introduced as well. To accommodate the high demand of renewable energy and the environment policy, the planning and operation the of Micro-source generators has been studied using HOMER. Simulation results show a case study of an optimal microgrid configuration on Ontario area in Canada. Sensitivity variables are specified to examine the effect of uncertainties, especially in a long-term planning. Also, demand side management plays an important role in the operation of Microgrid. Based on raw data, case studies are carried out to investigate and validate the demand response methods. Finally, the philosophy for Microgrid protection, especially Time-delay overcurrent protection, will be briefly introduced in both gird-connected and islanding modes. / Master of Science
38

Translating Discrete Time SIMULINK to SIGNAL

Messaoud, Safa 02 July 2014 (has links)
As Cyber Physical Systems (CPS) are getting more complex and safety critical, Model Based Design (MBD), which consists of building formal models of a system in order to be used in verification and correct-by-construction code generation, is becoming a promising methodology for the development of the embedded software of such systems. This design paradigm significantly reduces the development cost and time while guaranteeing better robustness, capability and correctness with respect to the original specifications, when compared with the traditional ad-hoc design methods. SIMULINK has been the most popular tool for embedded control design in research as well as in industry, for the last decades. As SIMULINK does not have formal semantics, the application of the model based design methodology and tools to its models is very limited. In this thesis, we present a semantic translator that transform discrete time SIMULINK models into SIGNAL programs. The choice of SIGNAL is motivated by its polychronous formalism that enhances synchronous programming with asynchronous concurrency, as well as, by the ability of its compiler of generating deterministic multi thread code. Our translation involves three major steps: clock inference, type inference and hierarchical top-down translation. We validate the semantic preservation of our prototype tool by testing it on different SIMULINK models. / Master of Science
39

Optimal Implementation of Simulink Models on Multicore Architectures with Partitioned Fixed Priority Scheduling

Bansal, Shamit 02 August 2018 (has links)
Model-based design based on the Simulink modeling formalism and the associated toolchain has gained its popularity in the development of complex embedded control systems. However,the current research on software synthesis for Simulink models has a critical gap for providing a deterministic, semantics-preserving implementation on multicore architectures with partitioned fixed-priority scheduling. In this thesis, we propose to judiciously assign task offset, task priority, and task communication mechanism, to avoid simultaneous access to shared memory by tasks on different cores, to preserve the model semantics, and to optimize the control performance. We develop two approaches to solve the problem: (a) a mixed integer linear programming (MILP) formulation; and (b) a problem specific exact algorithm that may run several magnitudes faster than MILP. / Master of Science / To save development time and money, automotive industries have been developing models using software, before implementing them directly on hardware. For reliability, the model generated from the software tool should behave in a well defined manner, coherent to the ideal design of the model. While the current tools are able to generate this reliable model for a single processor system, they are not able to do so for a system with multiple processors. When two or more processors contend to access the same resource at the same time, the existing tools are unable to provide a well defined execution order in their model. Since modern embedded systems need multiple processors to meet their increasing performance demands, it is imperative that the software tools scale up to multiple processors as well. In this work, we seek to bridge this gap by presenting two solutions that generate a deterministic software implementation of a system with multiple processors. In our solutions, we generate a model with well defined execution order by ensuring that at any given time, only one processor accesses a given resource. Furthermore, apart from ensuring determinism, we also improve upon the performance of the generated model by ensuring that there is minimal end-to-end latency in the system.
40

Développement prouvé de composants formels pour un générateur de code embarqué critique pré-qualifié / Proved Development of Formal Components for a Pre-Qualified Critical Embedded Code Generator

Izerrouken, Nassima 06 July 2011 (has links)
Nous nous intéressons au développement prouvé de composants formels pour un générateur de code pré-qualifié. Ce dernier produit un code séquentiel (C et Ada) pour des modèles d'entrée qui combinent les flots de données et de contrôle et qui présentent des possibilités d'exécution concurrente (Simulink/Stateflow et Scicos). Le développement prouvé permet de réduire le coût des tests et d'augmenter l'assurance des outils développés avec cette approche vis-à-vis de la qualification. Les phases de spécification, de développement et de vérification des outils développés sont effectuées avec l'assistant de preuve Coq. Ce dernier permet d'extraire le contenu calculatoire des composants en préservant les propriétés prouvées en Coq. Ce code extrait est ensuite intégré dans une chaîne complète de développement (chaîne de GeneAuto). Nous présentons un cadre formel, inspiré de l'analyse statique, qui s'appuie sur la sémantique abstraite et qui est instanciable sur plusieurs composants du générateur de code. Nous nous basons sur les ensembles partiellement ordonnés et sur le calcul de point fixe pour définir le cadre et effectuer les différentes analyses des composants du générateur de code. Ce cadre formel comporte toutes les preuves communes aux composants et indépendantes des analyses effectuées. Deux composants sont étudiés : l'ordonnanceur et le typeur des modèles d'entrée. / We are interested in the proved development of formal components for a pre-qualified code generator. This produces a sequential code (C and Ada) for input models that combine data and control flows, with potential concurrent execution (Simulink/Stateflow and Scicos). The proved development reduces test cost and increases insurance of components developed with this approach regarding the qualification. Phases of specification, development and verification of the developed components are done with the Coq proof assistant. This allows to extract the computational content of the components preserving the properties proved in Coq. The extracted code is then integrated into the complete development tool-chain (GeneAuto tool-chain). We present a formal framework, inspired from static analysis, based on the abstract semantics which is instantiable to several components of the code generator. We rely on partially ordered sets and fixed-point to define de formal framework and to perform the various analysis of components of the code generator. This formal framework includes all proofs common to the components and independent from the performed analyses. Two components are studied : the scheduler and the type checker of input models.

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