Reconhecimento de padrões de falhas em motores trifásicos utilizando redes neurais

This work presents a diagnosis faults system (rotor, stator, and contamination) of three-phase induction motor through equivalent circuit parameters and using techniques patterns recognition. The technology fault diagnostics in engines are evolving and becoming increasingly important in the field of electrical machinery. The neural networks have the ability to classify non-linear relationships between signals through the patterns identification of signals related. It is carried out induction motor´s simulations through the program Matlab R & Simulink R , and produced some faults from modifications in the equivalent circuit parameters. A system is implemented with multiples classifying neural network two neural networks to receive these results and, after well-trained, to accomplish the identification of fault´s pattern

Aplicação de técnicas de aprendizado de máquina no reconhecimento de classes estruturais de proteínas

Nowadays, classifying proteins in structural classes, which concerns the inference of patterns in their 3D conformation, is one of the most important open problems in Molecular Biology. The main reason for this is that the function of a protein is intrinsically related to its spatial conformation. However, such conformations are very difficult to be obtained experimentally in laboratory. Thus, this problem has drawn the attention of many researchers in Bioinformatics. Considering the great difference between the number of protein sequences already known and the number of three-dimensional structures determined experimentally, the demand of automated techniques for structural classification of proteins is very high. In this context, computational tools, especially Machine Learning (ML) techniques, have become essential to deal with this problem. In this work, ML techniques are used in the recognition of protein structural classes: Decision Trees, k-Nearest Neighbor, Naive Bayes, Support Vector Machine and Neural Networks. These methods have been chosen because they represent different paradigms of learning and have been widely used in the Bioinfornmatics literature. Aiming to obtain an improvment in the performance of these techniques (individual classifiers), homogeneous (Bagging and Boosting) and heterogeneous (Voting, Stacking and StackingC) multiclassification systems are used. Moreover, since the protein database used in this work presents the problem of imbalanced classes, artificial techniques for class balance (Undersampling Random, Tomek Links, CNN, NCL and OSS) are used to minimize such a problem. In order to evaluate the ML methods, a cross-validation procedure is applied, where the accuracy of the classifiers is measured using the mean of classification error rate, on independent test sets. These means are compared, two by two, by the hypothesis test aiming to evaluate if there is, statistically, a significant difference between them. With respect to the results obtained with the individual classifiers, Support Vector Machine presented the best accuracy. In terms of the multi-classification systems (homogeneous and heterogeneous), they showed, in general, a superior or similar performance when compared to the one achieved by the individual classifiers used - especially Boosting with Decision Tree and the StackingC with Linear Regression as meta classifier. The Voting method, despite of its simplicity, has shown to be adequate for solving the problem presented in this work. The techniques for class balance, on the other hand, have not produced a significant improvement in the global classification error. Nevertheless, the use of such techniques did improve the classification error for the minority class. In this context, the NCL technique has shown to be more appropriated

Classificação de padrões através de um comitê de máquinas aprimorado por aprendizagem por reforço

Reinforcement learning is a machine learning technique that, although finding a large number of applications, maybe is yet to reach its full potential. One of the inadequately tested possibilities is the use of reinforcement learning in combination with other methods for the solution of pattern classification problems. It is well documented in the literature the problems that support vector machine ensembles face in terms of generalization capacity. Algorithms such as Adaboost do not deal appropriately with the imbalances that arise in those situations. Several alternatives have been proposed, with varying degrees of success. This dissertation presents a new approach to building committees of support vector machines. The presented algorithm combines Adaboost algorithm with a layer of reinforcement learning to adjust committee parameters in order to avoid that imbalances on the committee components affect the generalization performance of the final hypothesis. Comparisons were made with ensembles using and not using the reinforcement learning layer, testing benchmark data sets widely known in area of pattern classification

Algoritmos genéticos aplicados a um comitê de LS-SVM em problemas de classificação

The pattern classification is one of the machine learning subareas that has the most outstanding. Among the various approaches to solve pattern classification problems, the Support Vector Machines (SVM) receive great emphasis, due to its ease of use and good generalization performance. The Least Squares formulation of SVM (LS-SVM) finds the solution by solving a set of linear equations instead of quadratic programming implemented in SVM. The LS-SVMs provide some free parameters that have to be correctly chosen to achieve satisfactory results in a given task. Despite the LS-SVMs having high performance, lots of tools have been developed to improve them, mainly the development of new classifying methods and the employment of ensembles, in other words, a combination of several classifiers. In this work, our proposal is to use an ensemble and a Genetic Algorithm (GA), search algorithm based on the evolution of species, to enhance the LSSVM classification. In the construction of this ensemble, we use a random selection of attributes of the original problem, which it splits the original problem into smaller ones where each classifier will act. So, we apply a genetic algorithm to find effective values of the LS-SVM parameters and also to find a weight vector, measuring the importance of each machine in the final classification. Finally, the final classification is obtained by a linear combination of the decision values of the LS-SVMs with the weight vector. We used several classification problems, taken as benchmarks to evaluate the performance of the algorithm and compared the results with other classifiers

Desenvolvimento e avaliação de padrão de torque para calibração de torquímetros em três faixas de medição

The continuous development of instruments and equipment used as tools or torque measurement in the industry is demanding more accurate techniques in the use of this kind instrumentation, including development of metrological characteristics in torque measurement. The same happens with the needs in calibration services. There is a diversity of methods of hand torque tools in the market with different measuring range but without complaining with technical standards in terms of requirements of quality and reliability. However, actually there is no choice of a torque measuring standard that fulfils, with low cost, the needs for the calibration of hand torque tools in a large number of ranges. The objective of this thesis is to show the development and evaluation of a torque measuring standard device with a conception to allow the calibration of hand torque tools with three levels of torque with an single instrument, promoting reduction of costs and time in the calibration, also offering reliability for the evaluation of torque measuring instrument. To attend the demand in the calibration of hand torque tools it is necessary that the calibration laboratories have a big collection of torque measuring standards, to fulfills the needs of the costumer, what is very costly. The development of this type of torque measuring standard revealed a viable technique and economically making possible the calibration of hand torque tools in different nominal ranges through a single measurement system versatile, efficient and of easy operation

Conversão do metano via oxicloração em reator de leito fixo utilizando catalisador do tipo CuCl2/SiO2

Supported catalysts of CuCl2 on sílica were used in the methane oxychlorination reaction. The materials were synthesized by the ion exchange technique in a basic solution, using a copper-ammonia complex with 3 and 6 % of nominal copper loading. The materials where characterized by thermogravimetry (TG), X-ray Fluorescence Spectroscopy (XRF), Temperature Programmed Reduction (TPR), Scanning Electron Microscopy with X-ray microanalysis (SEM/EDS), BET specific area and pore distribution. The characterization confirms the presence of copper on the support surface, concluding that the ion exchange technique was adequate in the catalyst synthesis. For the reaction test, an oxychlorination bench scale unit was employed. The tests were carried at 673 and 773 K. The results showed the influence of temperature and catalyst copper content on the oxychlorination of methane reaction

Aí marcador de especificidade de SN indefinidos: um estudo funcionalista com implicações para o ensino

This body of work aims to describe and analyze the behavior of the Aí specificity marker of indefinite Noun Phrases (NP), one of the many functions this linguistic item is developing in contemporary Brazilian Portuguese. From the Functional Linguistic theory perspective, the North American declivity, this project intends to outline the possible grammaticalization trajectory taken by the Aí specificity marker. It will be followed from its function as a spatial deitic up to its integration of indefinite NP, and the action of the fundamental principles of the theory, such as iconicity and informativity, will be observed on the use of this item. Following this, Aí specificity marker behavior will be described in respect to various linguistic and social factors: type of text where the occurrence is encountered, language modality in which the latter is produced, syntactic function developed by the NP specified by Aí , the existence or lack of material intervening between Aí and the NP nuclear noun, informational status of the NP adjugated to Aí , and finally, sex, education and age of the speaker. The occurrence of conversational implicatures will also be verified (GRICE, 1982) within the contexts of Aí specificity marker use. Reflections on the teaching of grammar will be made, as well as on the possibility and validity of working with noun phrase specificity markers in elementary and high school Portuguese language classes. The data used in this research project stem from Corpus Discurso & Gramática A língua falada e escrita na cidade do Natal (FURTADO DA CUNHA, 1998), and from Corpus Discurso & Gramática A língua falada e escrita na cidade do Rio de Janeiro (VOTRE; OLIVEIRA, 1995)

AI, LA, ALI e AQUI: gramaticalização de um paradigma emergente no domínio funcional da especificação nominal

In the light of the Functional Linguistic Theory, in its North-American version (HOPPER, 1987, 1991, 1998, 2008, 2010; GIVÓN, 2001; LEHMANN, 2002; HOPPER; TRAUGOTT, 2003; FURTADO DA CUNHA; OLIVEIRA; MARTELOTTA, 2003, among others), the general objective of this research is to demonstrate, based on morphosyntactic and semantic-pragmatic properties, that AQUI (HERE), AÍ, ALI and LÁ (THERE) are part of an emerging paradigm in Brazilian Portuguese recently constituted and still developing of forms indicating specificity in indefinite noun phrases (NP). The data that make up the corpus of this research were collected in the following large Brazilian oral corpora: the Corpus Discurso & Gramática: a língua falada e escrita na cidade de Natal (FURTADO DA CUNHA, 1998), the Banco Conversacional de Natal (FURTADO DA CUNHA, 2010), the Projeto Variação Linguística no Estado da Paraíba VALPB (HORA, 2005) and the Projeto Variação Linguística Urbana na Região Sul do Brasil VARSUL (VANDRESEN, 2002). Firstly, the behavior of the specificity markings AQUI, AÍ, ALI and LÁ is described with respect to many factors of morphosyntactic and semantic-pragmatic nature: type of construction in which the markers appeared; existence or not of intervening material between the specificity marker item and the NP s nuclear noun; type of noun to which AQUI, AÍ, ALI and LÁ are linked; syntactic function of the specified SN; informational status of the NP to which the specificity markers AQUI, AÍ, ALI and LÁ are attached; occurrence of conversational implicatures (GRICE, 1982) in the context of use of these specificity markers. Next, a possible grammaticalization trajectory is outlined, according to which AQUI, AÍ, ALI and LÁ would had gone from an early spatial deictic indication to the specificity indication. The results point to the existence of forms with varying degree of emergence in this new paradigm of nominal specification, with AÍ being, probably, the item most grammaticalized, followed by LÁ, then ALI and AQUI, which permanence in the paradigm do not yet appear to be consolidated

Qualidade de vida de pacientes com deformidade dentofacial

In the last decade, an increasing number of studies focusing on the impact of oral deformities on quality of life have been published. However, the evaluation of patients at different phases of the treatment has not been performed. Therefore, the purpose of this study was to determine the impact that dentofacial deformities have on patients` quality of life, as well as the influence exerted by social, economic, demographic and orthodontic factors, type and severity of malocclusion. A bicentric study - of the cross-sectional type of repeated panels - involving two cities - Natal and Rio de Janeiro - was carried out. A total of 227 patients participated in the study: 71 patients in the initial phase of the treatment (before any orthosurgical procedure), 115 patients in the pre-surgical (with braces) phase and 41 patients in the postoperative phase. The quality of life was measured using the Orthognatic Quality of Life Questionnnaire - OQLQ, translated and validated into Portuguese. The normative and aesthetic need for treatment was assessed with the Index of Orthodontic Treatment Need (IOTN) and the Dental Aesthetic Index (DAI); the social, economic and demographic factors, the type of service and malocclusion were also assessed. The data were analyzed through χ2/ Fisher`s exact test to seek the association between the nominal categorical variables in the three phases of treatment, Mann Whitney and Kruskal-Wallis test for gauging the existence of significant differences between two and three groups regarding each domain of OQLQ, respectively. For all tests, it was adopted a significance level of 5%. There was a statistically significant difference (p <0.001) in the general scores of OQLQ and in the domains of social aspects, facial aesthetics and oral function, when the "postoperative group" was compared to the "initial" and "orthodontic preparation" groups. Women, single, aged between 31 and 59 and living in Natal had the greatest impact on quality of life among patients in the "orthodontic preparation" group. Only the variable "income" (2 to 3 minimum wages), for the "initial" group, and gender (female) for the "postoperative" group, showed significant association with quality of life. The normative variable IOTN (DHC and AC) showed significant association with the OQLQ for the "initial" group, and the IOTN-AC-auto in the group of orthodontic preparation, being less important to women. We conclude that the ortho-surgical therapy has positive effects on quality of life after orthognathic surgery

Aplicação de ontologias para métodos de negociação de um sistema multiagente para o reconhecimento de padrões

The use of intelligent agents in multi-classifier systems appeared in order to making the centralized decision process of a multi-classifier system into a distributed, flexible and incremental one. Based on this, the NeurAge (Neural Agents) system (Abreu et al 2004) was proposed. This system has a superior performance to some combination-centered methods (Abreu, Canuto, and Santana 2005). The negotiation is important to the multiagent system performance, but most of negotiations are defined informaly. A way to formalize the negotiation process is using an ontology. In the context of classification tasks, the ontology provides an approach to formalize the concepts and rules that manage the relations between these concepts. This work aims at using ontologies to make a formal description of the negotiation methods of a multi-agent system for classification tasks, more specifically the NeurAge system. Through ontologies, we intend to make the NeurAge system more formal and open, allowing that new agents can be part of such system during the negotiation. In this sense, the NeurAge System will be studied on the basis of its functioning and reaching, mainly, the negotiation methods used by the same ones. After that, some negotiation ontologies found in literature will be studied, and then those that were chosen for this work will be adapted to the negotiation methods used in the NeurAge.

Dilema da diversidade-acurácia: um estudo empírico no contexto de multiclassificadores

Multi-classifier systems, also known as ensembles, have been widely used to solve several problems, because they, often, present better performance than the individual classifiers that form these systems. But, in order to do so, it s necessary that the base classifiers to be as accurate as diverse among themselves this is also known as diversity/accuracy dilemma. Given its importance, some works have investigate the ensembles behavior in context of this dilemma. However, the majority of them address homogenous ensemble, i.e., ensembles composed only of the same type of classifiers. Thus, motivated by this limitation, this thesis, using genetic algorithms, performs a detailed study on the dilemma diversity/accuracy for heterogeneous ensembles

Abordagem de construção de arquitetura homogênea para comitês via meta-aprendizagem

In the world we are constantly performing everyday actions. Two of these actions are frequent and of great importance: classify (sort by classes) and take decision. When we encounter problems with a relatively high degree of complexity, we tend to seek other opinions, usually from people who have some knowledge or even to the extent possible, are experts in the problem domain in question in order to help us in the decision-making process. Both the classification process as the process of decision making, we are guided by consideration of the characteristics involved in the specific problem. The characterization of a set of objects is part of the decision making process in general. In Machine Learning this classification happens through a learning algorithm and the characterization is applied to databases. The classification algorithms can be employed individually or by machine committees. The choice of the best methods to be used in the construction of a committee is a very arduous task. In this work, it will be investigated meta-learning techniques in selecting the best configuration parameters of homogeneous committees for applications in various classification problems. These parameters are: the base classifier, the architecture and the size of this architecture. We investigated nine types of inductors candidates for based classifier, two methods of generation of architecture and nine medium-sized groups for architecture. Dimensionality reduction techniques have been applied to metabases looking for improvement. Five classifiers methods are investigated as meta-learners in the process of choosing the best parameters of a homogeneous committee.

Controlador adaptativo backstepping a estrutura variável

Neste trabalho, um controlador adaptativo backstepping a estrutura variável (Variable Structure Adaptive Backstepping Controller, VS-ABC) é apresentado para plantas monovariáveis, lineares e invariantes no tempo com grau relativo unitário. Ao invés das tradicionais leis integrais para estimação dos parâmetros da planta, leis chaveadas são utilizadas com o objetivo de aumentar a robustez em relação a incertezas paramétricas e distúrbios externos, bem como melhorar o desempenho transitório do sistema. Adicionalmente, o projeto do novo controlador é mais intuitivo quando comparado ao controlador backstepping original, uma vez que os relés introduzidos apresentam amplitudes diretamente relacionadas com os parâmetros nominais da planta. Esta nova abordagem, com uso de estrutura variável, também reduz a complexidade das implementações práticas, motivando a utilização de componentes industriais, tais como, FPGAs (Field Programmable Gate Arrays ), MCUs (Microcontrollers) e DSPs (Digital Signal Processors). Simulações preliminares para um sistema instável de primeira e segunda ordem são apresentadas de modo a corroborar os estudos. Um dos exemplos de Rohrs é ainda abordado através de simulações, para os dois cenários adaptativos: o controlador backstepping adaptativo original e o VS-ABC

Aplicação do Sensoriamento Remoto e do Sistema de Informações Geográficas na Detecção de Manchas de Óleo na Região do Pólo de Exploração de Guamaré, R.N.

Objective to establish a methodology for the oil spill monitoring on the sea surface, located at the Submerged Exploration Area of the Polo Region of Guamaré, in the State of Rio Grande do Norte, using orbital images of Synthetic Aperture Radar (SAR integrated with meteoceanographycs products. This methodology was applied in the following stages: (1) the creation of a base map of the Exploration Area; (2) the processing of NOAA/AVHRR and ERS-2 images for generation of meteoceanographycs products; (3) the processing of RADARSAT-1 images for monitoring of oil spills; (4) the integration of RADARSAT-1 images with NOAA/AVHRR and ERS-2 image products; and (5) the structuring of a data base. The Integration of RADARSAT-1 image of the Potiguar Basin of day 21.05.99 with the base map of the Exploration Area of the Polo Region of Guamaré for the identification of the probable sources of the oil spots, was used successfully in the detention of the probable spot of oil detected next to the exit to the submarine emissary in the Exploration Area of the Polo Region of Guamaré. To support the integration of RADARSAT-1 images with NOAA/AVHRR and ERS-2 image products, a methodology was developed for the classification of oil spills identified by RADARSAT-1 images. For this, the following algorithms of classification not supervised were tested: K-means, Fuzzy k-means and Isodata. These algorithms are part of the PCI Geomatics software, which was used for the filtering of RADARSAT-1 images. For validation of the results, the oil spills submitted to the unsupervised classification were compared to the results of the Semivariogram Textural Classifier (STC). The mentioned classifier was developed especially for oil spill classification purposes and requires PCI software for the whole processing of RADARSAT-1 images. After all, the results of the classifications were analyzed through Visual Analysis; Calculation of Proportionality of Largeness and Analysis Statistics. Amongst the three algorithms of classifications tested, it was noted that there were no significant alterations in relation to the spills classified with the STC, in all of the analyses taken into consideration. Therefore, considering all the procedures, it has been shown that the described methodology can be successfully applied using the unsupervised classifiers tested, resulting in a decrease of time in the identification and classification processing of oil spills, if compared with the utilization of the STC classifier

Análise textual das representações discursivas no discurso político brasileiro: o discurso da primeira posse da presidenta Dilma Rousseff (1°/01/2011)

Cette recherche décrit la représentation discursive que la présidente Dilma Rousseff fait de soi-même, dans son discours devant le Congrès National, lors de la journée d’investiture, le 1/1/2011. Notre travail se situe dans le domaine théorique et méthodologique de la linguistique du texte et, plus spécialement, dans la perspective de l’Analyse Textuelle des Discours – ATD (ADAM, 2011 [2008a]), qui se définit comme « une théorie de la production co(n)textuelle de sens qui doit se fonder sur l’analyse de textes concrets ». Elle nous fournit la notion théorique et analytique de « représentation discursive », qui se focalise sur la dimension sémantique du texte. Nous nous appuyons, aussi, sur des travaux récents sur les représentations discursives, réalisés dans la recherche brésilienne sur l’ATD (RODRIGUES, PASSEGGI, SILVA NETO, 2010, 2012; RAMOS, 2011; OLIVEIRA, 2013; QUEIROZ, 2013; ZAMBLANO-OLIVEIRA, PASSEGGI, 2013). Les principales opérations sémantiques de construction de la représentation discursive utilisées dans notre travail sont la Référenciation et la Prédication. L’approche méthodologique est, en même temps, qualitative et quantitative, priorisant l’identification des occurrences, ainsi que la description détaillée de leurs valeurs sémantiques et textuelles. Les résultats de la recherche sont de trois ordres : méthodologique, théorique et descriptif-interprétatif. Méthodologique : nous proposons une approche que nous désignons comme « marquage textuel » (ou « mappage textuel ») qui permet de marquer (étiqueter) les valeurs sémantiques des formes linguistiques, permettant leur identification dans le flux textuel, c.-à-d., dans la dimension séquentiellecompositionnelle du texte. Théorique : nous introduisons la notion de « domaines de la représentation discursive » qui organisent et articulent les différents éléments qui composent la représentation discursive de la présidente. Quant aux résultats descriptifsinterprétatifs du discours de l’investiture, ils indiquent que la représentation discursive de la présidente se configure au moyen de différents domaines conceptuels, explicités par les référenciations et les prédications. Ils mettent en relief les désignations et les actions / états, aussi bien de la femme – domaine du genre – que de la présidente – domaine du rôle politique et institutionnel. La présidente se représente explicitement et avec emphase comme l’agent responsable par les actions exprimées par les prédications verbales (verbes d’action), consciente de l’importance de son rôle politique et social. Les prédications nominales signalent clairement une représentation discursive qui englobe les domaines conceptuels politique, moral, éthique, comportemental et émotionnel (forte, accueillante, pionnière, consolidatrice, infatigable, humble, engagée, démocrate, victorieuse et courageuse). Le discours d’investiture réalise, donc, des désignations positives de la présidente, lesquelles se situent dans un temps présent et prospectif – avec des perspectives de futur – comme leader politique du Brésil, avec une participation active dans la transformation du pays, tenant compte aussi de son histoire de vie, sa biographie de luttes. Ainsi, la description empirique et l’interprétation de ce discours particulier contribue à l’analyse textuelle des représentations discursives dans le discours politique brésilien contemporain. Elle soulève, aussi, des questions théoriques et méthodologiques qui nous semblent pertinentes pour le développement de cette aproche.