27 research outputs found

    Fuzzy model predictive control. Complexity reduction by functional principal component analysis

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    En el Control Predictivo basado en Modelo, el controlador ejecuta una optimización en tiempo real para obtener la mejor solución para la acción de control. Un problema de optimización se resuelve para identificar la mejor acción de control que minimiza una función de coste relacionada con las predicciones de proceso. Debido a la carga computacional de los algoritmos, el control predictivo sujeto a restricciones, no es adecuado para funcionar en cualquier plataforma de hardware. Las técnicas de control predictivo son bien conocidos en la industria de proceso durante décadas. Es cada vez más atractiva la aplicación de técnicas de control avanzadas basadas en modelos a otros muchos campos tales como la automatización de edificios, los teléfonos inteligentes, redes de sensores inalámbricos, etc., donde las plataformas de hardware nunca se han conocido por tener una elevada potencia de cálculo. El objetivo principal de esta tesis es establecer una metodología para reducir la complejidad de cálculo al aplicar control predictivo basado en modelos no lineales sujetos a restricciones, utilizando como plataforma, sistemas de hardware de baja potencia de cálculo, permitiendo una implementación basado en estándares de la industria. La metodología se basa en la aplicación del análisis de componentes principales funcionales, proporcionando un enfoque matemáticamente elegante para reducir la complejidad de los sistemas basados en reglas, como los sistemas borrosos y los sistemas lineales a trozos. Lo que permite reducir la carga computacional en el control predictivo basado en modelos, sujetos o no a restricciones. La idea de utilizar sistemas de inferencia borrosos, además de permitir el modelado de sistemas no lineales o complejos, dota de una estructura formal que permite la implementación de la técnica de reducción de la complejidad mencionada anteriormente. En esta tesis, además de las contribuciones teóricas, se describe el trabajo realizado con plantas reales en los que se han llevado a cabo tareas de modelado y control borroso. Uno de los objetivos a cubrir en el período de la investigación y el desarrollo de la tesis ha sido la experimentación con sistemas borrosos, su simplificación y aplicación a sistemas industriales. La tesis proporciona un marco de conocimiento práctico, basado en la experiencia.In Model-based Predictive Control, the controller runs a real-time optimisation to obtain the best solution for the control action. An optimisation problem is solved to identify the best control action that minimises a cost function related to the process predictions. Due to the computational load of the algorithms, predictive control subject to restric- tions is not suitable to run on any hardware platform. Predictive control techniques have been well known in the process industry for decades. The application of advanced control techniques based on models is becoming increasingly attractive in other fields such as building automation, smart phones, wireless sensor networks, etc., as the hardware platforms have never been known to have high computing power. The main purpose of this thesis is to establish a methodology to reduce the computational complexity of applying nonlinear model based predictive control systems subject to constraints, using as a platform hardware systems with low computational power, allowing a realistic implementation based on industry standards. The methodology is based on applying the functional principal component analysis, providing a mathematically elegant approach to reduce the complexity of rule-based systems, like fuzzy and piece wise affine systems, allowing the reduction of the computational load on modelbased predictive control systems, subject or not subject to constraints. The idea of using fuzzy inference systems, in addition to allowing nonlinear or complex systems modelling, endows a formal structure which enables implementation of the aforementioned complexity reduction technique. This thesis, in addition to theoretical contributions, describes the work done with real plants on which tasks of modeling and fuzzy control have been carried out. One of the objectives to be covered for the period of research and development of the thesis has been training with fuzzy systems and their simplification and application to industrial systems. The thesis provides a practical knowledge framework, based on experience

    Modelling and control of hybrid electric vehicles (a comprehensive review)

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    The gradual decline in global oil reserves and presence of ever so stringent emissions rules around the world, have created an urgent need for the production of automobiles with improved fuel economy. HEVs (hybrid electric vehicles) have proved a viable option to guarantying improved fuel economy and reduced emissions.The fuel consumption benefits which can be realised when utilising HEV architecture are dependent on how much braking energy is regenerated, and how well the regenerated energy is utilized. The challenge in developing an HEV control strategy lies in the satisfaction of often conflicting control constraints involving fuel consumption, emissions and driveability without over-depleting the battery state of charge at the end of the defined driving cycle.To this effect, a number of power management strategies have been proposed in literature. This paper presents a comprehensive review of these literatures, focusing primarily on contributions in the aspect of parallel hybrid electric vehicle modelling and control. As part of this treatise, exploitable research gaps are also identified. This paper prides itself as a comprehensive reference for researchers in the field of hybrid electric vehicle development, control and optimization

    Algorithms for Image Analysis in Traffic Surveillance Systems

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    Import 23/07/2015The presence of various surveillance systems in many areas of the modern society is indisputable and the most perceptible are the video surveillance systems. This thesis mainly describes novel algorithm for vision-based estimation of the parking lot occupancy and the closely related topics of pre-processing of images captured under harsh conditions. The developed algorithms have their practical application in the parking guidance systems which are still more popular. One part of this work also tries to contribute to the specific area of computer graphics denoted as direct volume rendering (DVR).Přítomnost nejrůznějších dohledových systémů v mnoha oblastech soudobé společnosti je nesporná a systémy pro monitorování dopravy jsou těmi nejviditelnějšími. Hlavní část této práce se věnuje popisu nového algoritmu pro detekci obsazenosti parkovacích míst pomocí analýzy obrazu získaného z kamerového systému. Práce se také zabývá tématy úzce souvisejícími s předzpracováním obrazu získaného za ztížených podmínek. Vyvinuté algoritmy mají své praktické uplatnění zejména v oblasti pomocných parkovacích systémů, které se stávají čím dál tím více populárními. Jedna část této práce se snaží přispět do oblasti počítačové grafiky označované jako přímá vizualizace objemových dat.Prezenční460 - Katedra informatikyvyhově

    Modelling and control of hybrid electric vehicles (a comprehensive review)

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    The gradual decline in global oil reserves and presence of ever so stringent emissions rules around the world, have created an urgent need for the production of automobiles with improved fuel economy. HEVs (hybrid electric vehicles) have proved a viable option to guarantying improved fuel economy and reduced emissions.The fuel consumption benefits which can be realised when utilising HEV architecture are dependent on how much braking energy is regenerated, and how well the regenerated energy is utilized. The challenge in developing an HEV control strategy lies in the satisfaction of often conflicting control constraints involving fuel consumption, emissions and driveability without over-depleting the battery state of charge at the end of the defined driving cycle.To this effect, a number of power management strategies have been proposed in literature. This paper presents a comprehensive review of these literatures, focusing primarily on contributions in the aspect of parallel hybrid electric vehicle modelling and control. As part of this treatise, exploitable research gaps are also identified. This paper prides itself as a comprehensive reference for researchers in the field of hybrid electric vehicle development, control and optimization

    Feature Extraction Methods for Character Recognition

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    A control-theoretical fault prognostics and accommodation framework for a class of nonlinear discrete-time systems

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    Fault diagnostics and prognostics schemes (FDP) are necessary for complex industrial systems to prevent unscheduled downtime resulting from component failures. Existing schemes in continuous-time are useful for diagnosing complex industrial systems and no work has been done for prognostics. Therefore, in this dissertation, a systematic design methodology for model-based fault prognostics and accommodation is undertaken for a class of nonlinear discrete-time systems. This design methodology, which does not require any failure data, is introduced in six papers. In Paper I, a fault detection and prediction (FDP) scheme is developed for a class of nonlinear system with state faults by assuming that all the states are measurable. A novel estimator is utilized for detecting a fault. Upon detection, an online approximator in discrete-time (OLAD) and a robust adaptive term are activated online in the estimator wherein the OLAD learns the unknown fault dynamics while the robust adaptive term ensures asymptotic performance guarantee. A novel update law is proposed for tuning the OLAD parameters. Additionally, by using the parameter update law, time to reach an a priori selected failure threshold is derived for prognostics. Subsequently, the FDP scheme is used to estimate the states and detect faults in nonlinear input-output systems in Paper II and to nonlinear discrete-time systems with both state and sensor faults in Paper III. Upon detection, a novel fault isolation estimator is used to identify the faults in Paper IV. It was shown that certain faults can be accommodated via controller reconfiguration in Paper V. Finally, the performance of the FDP framework is demonstrated via Lyapunov stability analysis and experimentally on the Caterpillar hydraulics test-bed in Paper VI by using an artificial immune system as an OLAD --Abstract, page iv

    Reaaliaikaiset ennustukset verkkopalveluissa

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    In this Master's Theses a real-time analytics pipeline is built to serve predictions to users based on the usage and the operational data of a Web service. The data of the service is analyzed and a predictive model is built using statistical learning methods. The pipeline is set up to serve the predictions real-time using components from Amazon Cloud Services. The aim is to show the user a prediction of how long will it take until she/he gets a verdict on her/his application from the service. As additional goals, the aim is to study the dataset and its possibilities and research the suitability of the Amazon Machine Learning service in real-time predictions in Web context. The features for the predictive model are selected by exploring the dataset and using the Amazon Machine Learning service to evaluate the features. The Amazon Machine Learning service is also used to build a predictive machine learning model. The real-time analytics pipeline is built using Amazon components and following the Lambda Architecture guidelines. The best model performed better than the baseline model, though only moderately. The data lacked some vital information for the prediction target such as information about the personnel. Implementing the pipeline with Amazon components was considered straightforward. The Lambda Architecture worked well for the problem. It was found out that the Amazon Machine Learning service is easy to use but its machine learning capabilities and user interface are limited. It was highlighted that it is essential to explore and learn the dataset before building or designing the pipeline, as the pipeline design depends heavily from the data and from the use case.Tässä diplomityössä on rakennettu reaaliaikainen analytiikkajärjestelmä, jolla näytetään ennustuksia käyttäjille eräässä verkkopalvelussa, perustuen verkkopalvelun käyttödataan ja operatiiviseen dataan. Verkkopalvelun dataa analysoidaan ja sen perusteella rakennetaan tilastollisiin menetelmiin pohjaava ennustava koneoppimismalli. Analytiikkajärjestelmä rakennetaan käyttäen komponentteja Amazonin pilvipalvelusta. Tarkoituksena on näyttää käyttäjälle ennustus siitä kauanko kestää, että hän saa vastauksen verkkopalveluun jättämäänsä hakemukseen. Tämän lisäksi tavoitteena on muodostaa ymmärrys verkkopalvelun datasta ja sen mahdollisuuksista, sekä tutkia soveltuuko Amazonin koneoppimispalvelu reaaliaikaisten ennustuksien näyttämiseen verkkoympäristössä. Ennustavan mallin ominaisuudet valittiin tarkastelemalla dataa ja evaluoimalla ominaisuudet Amazonin koneoppimispalvelun avulla. Amazonin koneoppimispalvelua käytettiin myös ennustavan koneoppimismallin rakentamiseen. Reaaliaikainen analytiikkajärjestelmä rakennettiin käyttäen komponentteja Amazonin pilvipalveluista ja seuraten Lambda-arkkitehtuurin suunnitteluperiaatteita. Paras rakennetuista koneoppimismalleista oli parempi kuin pohjamalli, joskaan ei mitenkään merkittävästi. Datasta puuttui joitain ennustettavan arvon kannalta tärkeitä tekijöitä kuten tietoa hakemuksia käsittelevästä henkilökunnasta. Analytiikkajärjestelmän rakentaminen Amazoniin osoittautui kuitenkin helpoksi. Amazonin koneoppimispalvelu todettiin helppokäyttöiseksi, vaikkakin se todettiin koneoppimisominaisuuksiltaan melko yksinkertaiseksi, sekä käyttöliittymän osalta rajoittuneeksi. Työssä korostetaan, että on tärkeää tutkia dataa ennen kuin rakentaa analytiikkajärjestelmän, sillä järjestelmän rakenne riippuu suuresti siitä, minkälaista data on ja mikä on sen sekä datan käyttötarkoitus

    Robust real-time control of a parallel hybrid electric vehicle

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    Air Force Institute of Technology Research Report 2018

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    This Research Report presents the FY18 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial resources are available and/or provided by a sponsor. In addition, AFIT provides research collaboration and technology transfer benefits to the public through Cooperative Research and Development Agreements (CRADAs). Interested individuals may discuss ideas for new research collaborations, potential CRADAs, or research proposals with individual faculty using the contact information in this document
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