A fuzzy set is one in which membership in a category is not Boolean, rather items have a degree of membership. Fuzzy databases expand on this idea by storing fuzzy data and allowing data to be retrieved based on its degree of membership. Determining the degree of membership that satisfies the largest number of users is difficult. Five different methods of determining the membership function: the Direct Rating Method, the Random Method with step sizes of .02 and .03, the Steplock Method, and the Weighted Average Method, were compared on the basis of convergence and user satisfaction. The results support use of the Direct Rating Method and the Steplock Method in conjunction with each other, to produce the membership function in the least time and with the highest user satisfaction.

Le travail de la thèse traite le problème de suivi de trajectoires des systèmes non linéaires incertains,dont le modèle nominal est construit à l’aide d’un système flou TS (Takagi-Sugeno) de type-2. Cedernier, exploite les modèles locaux du système obtenus par linéarisation autour de certains pointsde fonctionnement. La commande développée est basée sur les modes glissants d’ordre deux avecSuper-Twisting. Nous avons proposé deux systèmes flous type-2 adaptatifs, qui ont comme uniqueentrée la surface de glissement, pour résoudre le problème du calcul de la valeur optimale des gainsde la commande. Des résultats de simulation ont permis de comparer les performances de l’approcheproposée avec la méthode classique. Ensuite, nous avons introduit le concept de l’intégral sliding modepour imposer à priori le temps d’arrivée sur la surface de glissement. Les approches proposées sontgénéralisées aux cas des systèmes multivariables. Plusieurs résultats par simulation et implémentationen temps réel sont présentés pour illustrer les performances des approches développées / This work deals with a fuzzy tracking control design for uncertain nonlinear dynamic system withexternal disturbances and using a TS (Takagi-Sugeno) fuzzy model description. The control is basedon the Super-Twisting algorithm, which is among of second order sliding mode control. Moreover, twoadaptive fuzzy type-2 systems have been introduced to generate the two Super-Twisting signals toavoid both the chattering and the constraint on the knowledge of disturbances and uncertainties upperbounds. These adaptive fuzzy type-2 systems has only one input : the sliding surface, and one output :the optimale values of the control gains, which are hard to compute with the original algorithm.Simulation results are obtained in order to compare the performances of the proposed method tothat given by Levant. Then, we have introduced the integral sliding mode concept to impose inadvance the convergence time and the arrival on the sliding surface. The proposed approaches aregeneralized to the case of multivariable systems. Several results in simulation and in real time usinga benchmark are obtained to validate and to confirm the performances of our contributions.

This text is especialy intended to those who are interested into fuzzy logic and its application in relational databases. It is mainly focused on concept of fuzzyfied relational database and implementation of such database. This text consists of two parts: theoretical aspects of fuzzyfication and implementation part. Selected extension is based on fuzzy E-R model so the requirements of the real world can be better met. This paper also describes existing solutions on different level of fuzzyfication. Part of the work is design and implementation of a simple software for querying over fuzzyfied relational database. This work shoud also serve as a guide for design and implementation of fuzzy database.

Induction motors (IM) find widespread use in modern industry and for this reason they have been subject to a significant amount of research interest in recent times. One particular aspect of this research is the fault detection and diagnosis (FDD) of induction motors for use in a condition based maintenance (CBM) strategy; by effectively tracking the condition of the motor, maintenance action need only be carried out when necessary. This type of maintenance strategy minimises maintenance costs and unplanned downtime. The benefits of an effective FDD for IM is clear and there have been numerous studies in this area but few which consider the problem in a practical sense with the aim of developing a single system that can be used to monitor motor condition under a range of different conditions, with different motor specifications and loads. This thesis aims to address some of these problems by developing a general FDD system for induction motor. The solution of this problem involved the development and testing of a new approach; the adaptive mixed-residual approach (AMRA). The main aim of the AMRA system is to avoid the vast majority of unplanned failures of the machine and therefore as opposed to tackling a single induction motor fault, the system is developed to detect all four of the most statistically prevalent induction motor fault types; rotor fault, stator fault, air-gap fault and bearing fault. The mixed-residual fault detection algorithm is used to detect these fault types which includes a combination of spectral and model-based techniques coupled with particle swarm optimisation (PSO) for automatic identification of motor parameters. The AMRA residuals are analysed by a fuzzy-logic classifier and the system requires only current and voltage inputs to operate. Validation results indicate that the system performs well under a range of load torques and different coupling methods proving it to have significant potential for use in industrial applications.

Approved for public release, distribution is unlimited / One of the most significant challenges with modern intrusion detection systems is the high rate of false alarms that they generate. In order to lower this rate, we propose to reduce the amount of traffic sent a given intrusion detection system via a filtering process termed stream splitting. Each packet arriving at the system is treated as belonging to a connection. Each connection is then assigned to a network stream. A network stream can then be sent to an analysis engine tailored specifically for that type of data. To demonstrate a stream-splitting capability, both an extendable multi-threaded architecture and prototype were developed. This system was tested to ensure the ability to capture traffic and found to be able to do so with minimal loss at network speeds up to 20 Mb/s, comparable to several open-source analysis programs. The stream splitter was also shown to be able to correctly implement a traffic separation scheme. / Ensign, United States Navy

D.Ing. / Measuring the efficiency of water utilities has been a constant challenge to various stakeholders in the water sector. There are several factors that influence the efficiency of utilities. The following study examines the different factors and establishes a model to quantify the efficiency of water utilities using limited number of variables. It utilises Fuzzy Logic to develop the measurement model. The developed method can also be used to configure a new water utility for efficiency. In addition, the research highlights some possible imperfections in the water policies that can result in an inherent inefficiency of a water utility. The developed model can assist in setting ceiling levels for utility's water assets and labour, to ensure efficiency. The model is generic and can be applied to any country or community, and can be used to configure water utilities for the poor. The Model utilised "Matlab Fuzzy Tool Box student version 2009a" software as a tool to develop the Fuzzy Inference Engine for Utility Efficiency. The study is a contribution to the domain of knowledge of water engineering science.

M.Ing. / Columbus Stainless, a subsidiary of Acerinox, manufactures stainless steel in their plant located in Middelburg, South Africa. During the hot rolling operation the steel is rolled on a 4-high finishing mill where strip movement perpendicular to the rolling direction occurs. This movement is undesirable because it causes inferior product quality and may also lead to downtime if the strip moves past the edge of the rolls. In the past the operator made adjustments to the relative alignment of the rolls in the mill in an attempt to limit the sideways movement of the strip. In order to improve product quality and production throughput, the manual action of adjusting the parallelism of the rolls was replaced with an automatic steering control system. Analysis of the process revealed that several variables have an impact on the way the strip reacts to changes in the alignment of rolls in the mill. An adaptive fuzzy logic control system was designed and implemented in the real time control system of the mill. During commissioning the system did not have an adverse effect on production and all initial project criteria were met, as was stipulated in Section 1.4 of this document. The control system improved the strip movement by an average of 11% on various products rolled. Based on production data, the system potentially prevented two coils from leaving the rolls during the month long evaluation period and saved 40 minutes of production time. If the savings in material losses and the potential gain in production time are added the possible anticipated monetary saving is estimated to be about 24 million Rand a year.

Student Number : 9702018F - MSc(Eng) Dissertation - School of Electrical and Information Engineering - Faculty of Engineering and the Built Environment / Due to the volatile nature of the world economies, investing is crucial in ensuring an individual is prepared for future financial necessities. This research proposes an application, which employs computational intelligent methods that could assist investors in making financial decisions. This system consists of 2 components. The Forecasting Component (FC) is employed to predict the closing index price performance. Based on these predictions, the Stock Quantity Selection Component (SQSC) recommends the investor to purchase stocks, hold the current investment position or sell stocks in possession. The development of the FC module involved the creation of Multi-Layer Perceptron (MLP) as well as Radial Basis Function (RBF) neural network classifiers. TCategorizes that these networks classify are based on a profitable trading strategy that outperforms the long-term “Buy and hold” trading strategy. The Dow Jones Industrial Average, Johannesburg Stock Exchange (JSE) All Share, Nasdaq 100 and the Nikkei 225 Stock Average indices are considered. TIt has been determined that the MLP neural network architecture is particularly suited in the prediction of closing index price performance. Accuracies of 72%, 68%, 69% and 64% were obtained for the prediction of closing price performance of the Dow Jones Industrial Average, JSE All Share, Nasdaq 100 and Nikkei 225 Stock Average indices, respectively. TThree designs of the Stock Quantity Selection Component were implemented and compared in terms of their complexity as well as scalability. TComplexity is defined as the number of classifiers employed by the design. Scalability is defined as the ability of the design to accommodate the classification of additional investment recommendations. TDesigns that utilized 1, 4 and 16 classifiers, respectively, were developed. These designs were implemented using MLP neural networks, RBF neural networks, Fuzzy Inference Systems as well as Adaptive Neuro-Fuzzy Inference Systems. The design that employed 4 classifiers achieved low complexity and high scalability. As a result, this design is most appropriate for the application of concern. It has also been determined that the neural network architecture as well as the Fuzzy Inference System implementation of this design performed equally well.

Orientadora: Paloma Maria Silva Rocha Rizol / Coorientadora: Marcela A. G. M. Freitas / Banca: Valério Antonio Pamplona Salomon / Banca: Fabrício Maciel Gomes / Resumo: Na busca pela competitividade, muitas empresas acabam adotando estratégias muito semelhantes baseadas nas práticas mais usuais e difundidas em seus respectivos negócios. Além dos recursos financeiros em si, as empresas também investem tempo e esforços para atingir desempenhos semelhantes às mais competitivas, as quais julgam ser o "benchmarking", ou seja, a referência em seus negócios. Entretanto, buscar somente se espelhar nas melhores práticas das empresas de referência não possibilita tornar-se líder no negócio, pois para tanto seriam necessários outros ingredientes, outras estratégias que façam a diferença. Quando direcionado o foco para o produto em si, no caso deste estudo em específico da indústria automobilística que é um segmento bastante competitivo no mundo, faz-se necessário estratégias muito mais sofisticadas ou muitas vezes ainda inexistentes. Mencionado por diversos líderes e executivos de grandes empresas multinacionais como uma metodologia eficaz, o Design for Six Sigma, ou simplesmente DFSS, possibilita aprofundamentos e desdobramentos muito importantes para o entendimento dos mercados, de seus clientes, das suas necessidades e anseios. Pela flexibilidade do uso da metodologia do DFSS, torna-se possível desenvolver propostas e soluções para um dos diferenciais mais importantes neste mercado competitivo, a inovação. Em função da subjetividade presente sob alguns aspectos do conceito deste diferencial, propôs-se adotar a lógica fuzzy para se trabalhar com as v... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: To pursue the competitiveness, many companies end up adopting similar strategies based on the most common and disseminated practices in their respective business. Beyond the financial resources, the companies also invest time and efforts in order to achieve similar performances of the most competitive ones which they deem to be "benchmarking", i.e. the reference in your business. However, simply adopting the best practices of those reference companies will not allow become a leader in their businesses, since it would require other ingredients, other strategies that make the difference. When it focuses on the product itself, specifically in the case of this study about the automotive industry, which is a very competitive segment in the world, it is necessary much more sophisticated strategies or even non-existent yet. Mentioned by several leaders and executives of multinational companies as an efficient methodology, the Design for Six Sigma, or simply DFSS, enables to understand their markets, their customers, respective necessities and yearnings, in a deep way and their deployments as well. By the flexibility of using DFSS methodology, it becomes possible to develop proposals and solutions to one of the most important differentials in this competitive market, the innovation. Due to the subjectivity around some aspects of the concept of that differential, it is proposed to adopt the fuzzy logic, to work on the most important linguistic variables and, combined with the Taguchi'... (Complete abstract click electronic access below) / Mestre

A pesquisa de cunho qualitativo aqui apresentada tem como propósito discutir o valor e o papel da lógica fuzzy na solução de problemas reais, dada a característica de suas ferramentas para lidar com questões subjetivas, uma vez que as soluções de problemas provenientes do mundo real estão carregadas de relações construídas no mundo interno do resolvedor são oriundas da subjetividade do sujeito resolvedor. Nosso trabalho teve como um dos objetivos responder às questões: Quais os pressupostos teóricos da teoria fuzzy e quais as possibilidades de reconhecimento de seu valor e de seu papel para a Educação Matemática? Como o pensamento matemático do aluno lida com o raciocínio fuzzy? Com essa perspectiva, aproximamo-nos dos alunos do Curso de Licenciatura das Faculdades Unificadas da Fundação Educacional de Barretos UNFEB , na busca de evidências, em termos de pesquisa, por meio de dois questionários e um minicurso ministrado pelo pesquisador, nesta ordem: questionário, minicurso e questionário. O primeiro questionário instigava o uso de variáveis subjetivas na solução de questões. O minicurso teve como foco central a resolução de um mesmo problema, utilizando matemática clássica e matemática fuzzy. O questionário final, de cunho avaliativo, verificava o uso, pelo aluno, das ferramentas da teoria fuzzy em problemas semelhantes aos anteriores. Os resultados da pesquisa indicaram a pouca experiência dos alunos com o raciocínio fuzzy dada, talvez, a dominância da matemática formal/determinística; mostraram, também, evidências de que os mesmos problemas, resolvidos verbalmente, sem o uso da matemática, revelam-se especialmente desafiadores quando é solicitada uma solução matemática fuzzy. / The qualitative research here presented intends to discuss the value and the role of fuzzy logic in the solution of real problems, due to the characteristic of its tools to deal with subjective questions, since the solution of problems originated in the real world are loaded with relationships built in the resolvers internal world they are originated in the subjectresolvers subjectivity. Our work had as one of its goals to answer the questions: Which are Fuzzy Theory theoretical assumptions and what are the possibilities of acknowledgement of its value and role to Mathematical Education?; How does the students mathematical thinking deal with fuzzy reasoning? On this perspective, we approached the students of the Curso de Licenciatura das Faculdades Unificadas da Fundação Educacional de Barretos - UNFEB searching for research evidences by means of two questionnaires and a mini-course taught by the researcher, in the following order: questionnaire, mini-course and questionnaire. The first questionnaire incited the use of subjective variables in the solution of questions. The mini-course, after the questionnaire, had as main focus the solution of one (same) problem using classical mathematics and fuzzy mathematics. The final questionnaire, of evaluative nature, verified the students use of fuzzy theory tools for problems similar to the previous ones. The research results indicated the students little experience with fuzzy reasoning maybe due to the dominance of formal/deterministic mathematics as well as showing evidences that the same problems solved verbally without the use of mathematics were especially challenging when a fuzzy mathematics solution was requested.