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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.
141

Lógica nebulosa (\'fuzzy\') aplicada na determinação dos parâmetros de trabalho de fornos industriais de têmpera contínua para o aço CK 75. / Fuzzy logic applied in the determination of the parameters of work of industrial furnace of continuos tempering of the steel CK75.

Barbosa Junior, José 22 November 2006 (has links)
Este trabalho apresenta o projeto de um sistema gerador de \"set-point\" (GSP), utiliza-do na determinação dos parâmetros de trabalho de fornos industriais de têmpera contínua de aços ao carbono, cuja modelagem é baseada na lógica \"fuzzy\". O trabalho é constituído de três etapas básicas: primeiro, estudou-se os princípios metalúrgicos do aço e do processo de têmpera, necessários para o entendimento do problema, tendo como foco no aço CK75 de grande aplicação industrial. Segundo, estudou-se a funcionalidade de todas as partes constitu-intes do forno e seu modo de operação. Na terceira etapa, baseado em entrevistas com os ope-radores e técnicos em metalurgia, considerados especialistas no processo de têmpera, reali-zou-se a modelagem \"fuzzy\". Constatou-se de que forma as partes do forno afetam a trans-formação do aço, as variáveis de entrada e saída relevantes para o GSP e finalmente realizou-se o GSP com o MATLAB®. O modelo foi exaustivamente testado na produção de aço tem-perado, em um dos fornos da empresa Mangels, o que possibilitou sua validação de forma incontestável. / This work presents the project of a generating system of \"set-point\" (GSP), used in the determination of the parameters of work of a process of continuous tempering of carbon steels, whose modeling is based on the \"fuzzy\" logic. The work is made of three basic stages. First of all the principles of metallurgy for the steel and temper process, which are necessary for the understanding of the problem are studied. It is focused in the steel CK75 of great in-dustrial application. In the second stage, the functionality of all parts of the furnace and its operation way is studied. In the last stage a \"fuzzy\" modeling is accomplished, based on inter-views with the operators and technicians in metallurgy, who are considered specialists in the temper process. It is identified how the parts of the oven affect the transformation of the steel, variable input and output relevant to GSP. Finally will use the GSP with MATLAB® is car-ried out. The model was tested in exhaustive way in one of the furnace of the company Man-gels what made its incontrovertible validation possible.
142

A rule-based drawing robot.

January 1999 (has links)
by Tang Kai Hung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references. / Abstracts in English and Chinese. / Acknowledgements --- p.vi / Abstract --- p.1 / Chapter 1 --- Introduction / Chapter 1.1 --- Motivation --- p.3 / Chapter 1.2 --- Objective --- p.7 / Chapter 1.3 --- Outline --- p.9 / Chapter 2 --- Color Identification / Chapter 2.1 --- Grabbing --- p.11 / Chapter 2.2 --- Digital Image Representation --- p.13 / Chapter 2.3 --- Color Segmentation --- p.15 / Chapter 2.3.1 --- Fuzzy Rule-Based Method --- p.15 / Chapter 2.3.2 --- Fuzzy Clustering Method --- p.20 / Chapter 2.4 --- Conclusion --- p.25 / Chapter 3 --- Shape Recognition / Chapter 3.1 --- Labeling --- p.29 / Chapter 3.1.1 --- Pre-processing --- p.29 / Chapter 3.1.2 --- Connected Components --- p.30 / Chapter 3.2 --- Blob Analysis --- p.33 / Chapter 3.2.1 --- Characteristic Values --- p.33 / Chapter 3.2.2 --- Corner Detection --- p.35 / Chapter 3.3 --- Type Classification --- p.37 / Chapter 3.3.1 --- Standard Blob --- p.37 / Chapter 3.3.2 --- Non-standard Object --- p.39 / Chapter 3.4 --- Flow Chart --- p.39 / Chapter 3.5 --- Point Generation --- p.42 / Chapter 3.5.1 --- Draw the Boundary --- p.42 / Chapter 3.5.2 --- Filling in Color by Lines --- p.48 / Chapter 3.6 --- Conclusion --- p.50 / Chapter 4 --- Drawing / Chapter 4.1 --- Difficulties & Remedies --- p.54 / Chapter 4.1.1 --- Data Transmission Difficulty --- p.54 / Chapter 4.1.2 --- Robot Drawing Plane --- p.56 / Chapter 4.2 --- Coordinates Conversion --- p.59 / Chapter 4.3 --- Quantitative Performance Measure --- p.64 / Chapter 4.4 --- Conclusion --- p.66 / Chapter 5 --- Conclusions & Future Works --- p.69 / Appendix / Bibliography
143

A fluid power application of alternative robust control strategies

Pannett, Richard January 2010 (has links)
This thesis presents alternative methods for designing a speed controller for a hydrostatic power transmission system. Recognising that such a system, comprising a valve controlled motor supplied by the laboratory ring main and driving a hydraulic pump as a load, contains significant non-linearities, the thesis shows that robust 'modern control' approaches may be applied to produce viable controllers without recourse to the use of a detailed model of the system. In its introduction, it considers why similar approaches to the design of fluid power systems have not been applied hitherto. It then sets out the design and test, in simulation and on a physical rig, of two alternative linear controllers using H∞ based methods and a 'self organising fuzzy logic' controller (SOFLC). In the linear approaches, differences between the characteristics of the system and the simple models of it are accommodated in the controller design route as 'perturbations' or 'uncertainties'. The H∞ based optimisation methods allow these to be recognised in the design. “Mixed sensitivity” and “Loop shaping” methods are each applied to design controllers which are tested successfully on the laboratory rig. The SOFLC in operation does not rely on a model, but instead allows fuzzy control rules to evolve. In the practical tests, the system is subjected to a range of disturbances in the form of supply pressure fluctuations and load torque changes. Also presented are test results for proportional and proportional plus integral (PI) controllers, to provide a reference. It is demonstrated qualitatively that performance using the linear controllers is superior to that using proportional and PI controllers. An increased range of stable operation is achieved by the controller designed using “loop shaping” – performance is enhanced by the use of two controllers selected automatically according to the operating speed, using a “bumpless” transfer routine. The SOFLC proved difficult to tune. However, stable operation was achieved.
144

Um controlador de flutter baseado em lógica difusa / A fuzzy controller based on fuzzy logic

Rocha, José Celso 23 June 2003 (has links)
O controle de flutter é um problema cuja solução é almejada ao longo de décadas e que ainda se apresenta como um desafio considerável. Os desafios residem basicamente no projeto de dispositivos de atuação eficientes e na síntese das leis de controle. A lógica difusa se mostra como uma técnica promissora e efetiva de controle. Neste trabalho é proposto um controlador difuso para o controle de flutter em uma asa com aerofólio do tipo NACA 0012, tendo como superfície de controle um flap. Este modelo físico é acoplado a um dispositivo elástico de sustentação da asa - DESA, que possibilita os movimentos de arfagem e deslocamento vertical. Para o desenvolvimento do modelo matemático são utilizadas as Equações de Lagrange e o Princípio do Trabalho Virtual. A determinação dos parâmetros estruturais do conjunto ASA/DESA é realizada a partir de um modelo em elementos finitos e de uma análise modal experimental. Os modos de vibrar são determinados através do ERA - Eigensystem Realization Algorithm. O estudo da atuação do controlador difuso é realizado através de simulação computacional e de análise experimental. Dois modelos difusos são utilizados na construção do controlador, o de Mamdani e o de Takagi-Sugeno-Kang. Os resultados obtidos mostram que o controlador difuso, para os dois modelos, é bastante eficiente no controle do flutter. / Flutter control is a problem for which solution has been longed for decades and still is a considerable challenge. The challenges reside basically in the development of devices with efficient performance and in the synthesis of the control laws. Fuzzy logic appears as a promising and effective technique of control. In this work, a fuzzy controller is proposed for flutter control of a wing with NACA 0012 airfoil section, having as control surface a trailing edge flap. This physical model is coupled to the elastic support device of the wing - DESA, which allows plunge and pitch displacements. For the development of the mathematical modeI, the Lagrange Equations and the Principle of the Virtual Work are used. The determination of the structural parameters of the Wing/DESA device is accomplished starting from a finite element model and from an experimental modal analysis. The vibrating modes are obtained using the Eigensystem Realization AIgorithm - ERA. The study of the fuzzy controllers performance is accomplished through simulation and experimental analysis. Two fuzzy models are used for the controller: the Mamdani and the Takagi- Sugeno-Kang. The results show that both fuzzy controllers are quite efficient in the control of flutter.
145

Um controlador de flutter baseado em lógica difusa / A fuzzy controller based on fuzzy logic

José Celso Rocha 23 June 2003 (has links)
O controle de flutter é um problema cuja solução é almejada ao longo de décadas e que ainda se apresenta como um desafio considerável. Os desafios residem basicamente no projeto de dispositivos de atuação eficientes e na síntese das leis de controle. A lógica difusa se mostra como uma técnica promissora e efetiva de controle. Neste trabalho é proposto um controlador difuso para o controle de flutter em uma asa com aerofólio do tipo NACA 0012, tendo como superfície de controle um flap. Este modelo físico é acoplado a um dispositivo elástico de sustentação da asa - DESA, que possibilita os movimentos de arfagem e deslocamento vertical. Para o desenvolvimento do modelo matemático são utilizadas as Equações de Lagrange e o Princípio do Trabalho Virtual. A determinação dos parâmetros estruturais do conjunto ASA/DESA é realizada a partir de um modelo em elementos finitos e de uma análise modal experimental. Os modos de vibrar são determinados através do ERA - Eigensystem Realization Algorithm. O estudo da atuação do controlador difuso é realizado através de simulação computacional e de análise experimental. Dois modelos difusos são utilizados na construção do controlador, o de Mamdani e o de Takagi-Sugeno-Kang. Os resultados obtidos mostram que o controlador difuso, para os dois modelos, é bastante eficiente no controle do flutter. / Flutter control is a problem for which solution has been longed for decades and still is a considerable challenge. The challenges reside basically in the development of devices with efficient performance and in the synthesis of the control laws. Fuzzy logic appears as a promising and effective technique of control. In this work, a fuzzy controller is proposed for flutter control of a wing with NACA 0012 airfoil section, having as control surface a trailing edge flap. This physical model is coupled to the elastic support device of the wing - DESA, which allows plunge and pitch displacements. For the development of the mathematical modeI, the Lagrange Equations and the Principle of the Virtual Work are used. The determination of the structural parameters of the Wing/DESA device is accomplished starting from a finite element model and from an experimental modal analysis. The vibrating modes are obtained using the Eigensystem Realization AIgorithm - ERA. The study of the fuzzy controllers performance is accomplished through simulation and experimental analysis. Two fuzzy models are used for the controller: the Mamdani and the Takagi- Sugeno-Kang. The results show that both fuzzy controllers are quite efficient in the control of flutter.
146

Modelagem matemática e computacional na avaliação do uso de água magnetizada na irrigação do rabanete utilizando o sistema Mamdani /

Boso, Ana Cláudia Marassá Roza, 1987. January 2018 (has links)
Orientador: Camila Pires Cremasco Gabriel / Banca: Daniel dos Santos Viais Neto / Banca: Raul Andres Martinez Uribe / Resumo: Este trabalho teve por objetivo estudar a produtividade da cultura do Rabanete, irrigada com dois tipos de tratamento: água convencional (AC) e água tratada magneticamente (ATM), utilizando modelos Fuzzy e estatísticos. Para isso, o estudo foi divido em dois capítulos: o primeiro descreve os resultados obtidos com a produtividade da cultura do rabanete, utilizando água convencional e água tratada magneticamente para irrigação. Houve a comparação entre os modelos Fuzzy (triangular e gaussiano) com o modelo estatístico, conforme a variável de produtividade fitomassa fresca da raiz tuberosa (FFRT), e a comparação entre os resultados obtidos com o tipo de tratamento irrigado. O coeficiente de determinação indicam que os modelos Fuzzy demostraram melhores resultados da produtividade da cultura, sendo que o modelo Fuzzy gaussiano demostrou a realidade agronômica com maior eficiência. A utilização da ATM (Água Tratada Magneticamente) permite obter melhores resultados da produtividade da cultura, quando analisada a variável FFRT e a eficiência dos modelos Fuzzy, em apresentar os dados de forma agronômica, principalmente o modelo Fuzzy gaussiano. O segundo capítulo apresenta os resultados alcançados com o desenvolvimento das variáveis biométricas da cultura do Rabanete, quando irrigada com água convencional e magnetizada. Para isso foi utilizada a modelagem Fuzzy e a modelagem estatística, para explicar o comportamento das variáveis biômetras. Em seguida foi realizada a comparação dos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The current study aimed to study the productivity of the Radish culture, irrigated with two types of treatment: conventional water (AC) and magnetically treated water (ATM), by means of Fuzzy's and statistical models. For this, the study was divided in two chapters: the first one describes the results obtained with the productivity of the radish culture, using conventional water and magnetically treated water for irrigation. The Fuzzy's (triangular and Gaussian) models were compared with the statistical model, according to the biometric fresh tuberous root biomass (FFRT), and the comparison between the results obtained with the type of irrigated treatment. The coefficient of determination indicates that the Fuzzy's models showed better results of the crop productivity, and the Gaussian Fuzzy's model showed the agronomic reality with greater efficiency. The use of ATM (Magnetically Treated Water) allows better results of crop productivity, when FFRT variable and Fuzzy's models efficiency, to present the data in agronomic form, mainly the Gaussian Fuzzy's model. The second chapter presents the results obtained with the development of the biometric variables of the culture of the Radish, when irrigated with conventional and magnetized water. Fuzzy's modeling and statistical modeling were used to explain the behavior of biometric variables. Afterwards, a comparison of the developed models was performed, and verified that the Fuzzy's model presented with greater efficiency the agronomic behavior of the plant. Afterwards, the results obtained were compared in the biometric variables, with AC and ATM treatment. In making such a comparison, it was verified the effectiveness of using ATM to obtain productivity of the Radish culture. In general, the preparation of the Fuzzy's models shows that the biometric variables of the crop and the productivity of the radish reached satisfactory results, ... / Mestre
147

Razvoj namenskog sistema fazi logike za primenu u sistemima za upravljanje XML dokumentima / The development a dedicated system for the application fuzzy logic in systems for manage of XML documents

Panić Goran 15 April 2014 (has links)
<p>U stvarnom životu većina informacija dolazi kao neprecizne ili<br />nepotpune vrednosti.&nbsp; XML tehnologija je napravila veliki<br />napredak u oblasti skladi&scaron;tenja i prenosa podataka.&nbsp; Doktorska<br />disertacija defini&scaron;e fazi XML sintaksu koja kombinuje neodređenosti<br />u vrednostima XML-a i neodređenosti u strukturi XML dokumenata.<br />Takođe, rad pro&scaron;iruje standardnu XQuery upitnu sintaksu fazi<br />elementima i uvodi prioritete i pragove zadovoljenja pomoću<br />GPFCSP-a. Za razliku od drugih radova koji se fokusiraju na<br />postavljanje teorija i definisanje sintaksi, rad posebnu pažnju<br />posvećuje praktičnoj upotrebi definisanih sintaksi. Za potrebe<br />istraživanja razvijen je softverski paket koji omogućava rad kako sa<br />standardnim, tako i sa fazi XML, XSD i DTD dokumentima, kao i<br />postavljanje i izvr&scaron;avanje prioritizovanih fazi XQuery upita. Alat je<br />testiran nad primerima iz prakse.</p> / <p>In real life, as opposed to virtual, most information comes in the<br />form of imprecise or incomplete values. XML&nbsp; technology has<br />made great progress in the field of storage and data transfer.<br />This doctoral dissertation&nbsp; developed XML extension which<br />combines&nbsp; indefiniteness in the values of XML and<br />indefiniteness in the structure of XML into a single fuzzy XML<br />extension. Furthermore,&nbsp; dissertation&nbsp; expands XQuery syntax<br />with fuzzy values and&nbsp; includes priorities and thresholds in<br />fuzzy XQuery extension using&nbsp; GPFCSP for the first time.<br />Unlike other papers that focus on setting up theories and<br />defining syntax, in this&nbsp; dissertation, special attention&nbsp; is turned<br />to their practical use. A tool for working with XML, XSD and<br />DTD documents and prioritized fuzzy XQuery extension<br />queries has been developed. The tool has been tested on<br />practical examples.</p>
148

Application of fuzzy logic, GIS and remote sensing to the assessment of environmental factors for extensive brackishwater aquaculture in Indonesia

-, Tarunamulia, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW January 2008 (has links)
Extensive brackishwater aquaculture, which is a dominant land-based aquaculture system in Indonesia, has experienced variable success in most farming locations in the country due to poor understanding of spatial assessment of environmental factors and rudimentary site selection criteria. Despite tremendous potential, the application of GIS and remote sensing in spatial assessment has tended to focus on Boolean (Crisp) logic that is often unable to effectively handle the complexity and spatial variability of key environmental factors for the development of aquaculture. This study explored the possibility of integrating fuzzy logic techniques into GIS and remote sensing technology to generate more robust mapping protocols in aquaculture, compensating for the disadvantages of the Crisp method. Two models were developed in two different provinces in Indonesia to spatially assess soil and hydrological constraints on extensive brackishwater aquaculture. The soil assessment focussed on acid sulfate soils (ASS) and sandy-textured sediments in Aceh, and the hydrological study focused on investigating important wave parameters that influence the suitability of coastal areas for siting extensive pond units in South Sulawesi. The study showed that fuzzy-based classification methods, integrated into the image analysis, was highly effective in identifying existing and potential pond areas for extensive brackishwater aquaculture compared to the best result of the commonly used Crisp method. By addition of one or more key environmental variables of ASS into the fuzzy-classified existing and potential ponds areas, a very robust predictive tool to identify potential ponds areas affected by ASS in Kembang Tanjung, Aceh was developed. A more detailed assessment of ASS developed in this study also successfully highlighted the severity of sandy-soils and identified them as another key soil variable that has and will severely impact on pond productivity. The second model developed by the study enables fuzzy logic to be integrated into GIS to predict the possible areas impacted by moderate to high energy wave conditions and possible ways of minimising their direct and indirect impacts. The models developed in this study were shown to work well in both study sites and can be applied elsewhere. The mapping outputs are easy to interpret even by stakeholders with no prior training in map reading. Overall, the models have the potential to reduce planning errors and to improve decision making in aquaculture provided that quality data sources are used.
149

Fuzzy concepts and formal methods.

Matthews, Chris, mikewood@deakin.edu.au January 2001 (has links)
It has been recognised that formal methods are useful as a modelling tool in requirements engineering. Specification languages such as Z permit the precise and unambiguous modelling of system properties and behaviour. However some system problems, particularly those drawn from the information systems problem domain, may be difficult to model in crisp or precise terms. It may also be desirable that formal modelling should commence as early as possible, even when our understanding of parts of the problem domain is only approximate. This thesis suggests fuzzy set theory as a possible representation scheme for this imprecision or approximation. A fuzzy logic toolkit that defines the operators, measures and modifiers necessary for the manipulation of fuzzy sets and relations is developed. The toolkit contains a detailed set of laws that demonstrate the properties of the definitions when applied to partial set membership. It also provides a set of laws that establishes an isomorphism between the toolkit notation and that of conventional Z when applied to boolean sets and relations. The thesis also illustrates how the fuzzy logic toolkit can be applied in the problem domains of interest. Several examples are presented and discussed including the representation of imprecise concepts as fuzzy sets and relations, system requirements as a series of linguistically quantified propositions, the modelling of conflict and agreement in terms of fuzzy sets and the partial specification of a fuzzy expert system. The thesis concludes with a consideration of potential areas for future research arising from the work presented here.
150

Fuzzy logic control of an inverted pendulum with vision feedback

Holzapfel, Frank G. 25 May 1994 (has links)
Recent technical progress has made new forms of controller implementations on computers possible. Especially the technique of Fuzzy Logic Control has found a growing number of applications. Also the development of fast A/D converters has made the acquisation of data with vision based systems possible. In this project we combine the two techniques of Fuzzy Logic Control and Vision Feedback to control an inverted pendulum and to determine their usefulness and limitations. The experiment was conducted and provided us with the data necessary to judge the performance of the new control strategy. The gathered data support the hypothesis that it is possible to control the inverted pendulum with Fuzzy Logic Control using Vision Feedback, though not without limitations. / Graduation date: 1995

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