Estudo avaliativo de um algoritmo genético auto-organizável e multiobjetivo utilizando aprendizado de máquina para aplicações de telecomunicações

This paper presents an evaluative study about the effects of using a machine learning technique on the main features of a self-organizing and multiobjective genetic algorithm (GA). A typical GA can be seen as a search technique which is usually applied in problems involving no polynomial complexity. Originally, these algorithms were designed to create methods that seek acceptable solutions to problems where the global optimum is inaccessible or difficult to obtain. At first, the GAs considered only one evaluation function and a single objective optimization. Today, however, implementations that consider several optimization objectives simultaneously (multiobjective algorithms) are common, besides allowing the change of many components of the algorithm dynamically (self-organizing algorithms). At the same time, they are also common combinations of GAs with machine learning techniques to improve some of its characteristics of performance and use. In this work, a GA with a machine learning technique was analyzed and applied in a antenna design. We used a variant of bicubic interpolation technique, called 2D Spline, as machine learning technique to estimate the behavior of a dynamic fitness function, based on the knowledge obtained from a set of laboratory experiments. This fitness function is also called evaluation function and, it is responsible for determining the fitness degree of a candidate solution (individual), in relation to others in the same population. The algorithm can be applied in many areas, including in the field of telecommunications, as projects of antennas and frequency selective surfaces. In this particular work, the presented algorithm was developed to optimize the design of a microstrip antenna, usually used in wireless communication systems for application in Ultra-Wideband (UWB). The algorithm allowed the optimization of two variables of geometry antenna - the length (Ls) and width (Ws) a slit in the ground plane with respect to three objectives: radiated signal bandwidth, return loss and central frequency deviation. These two dimensions (Ws and Ls) are used as variables in three different interpolation functions, one Spline for each optimization objective, to compose a multiobjective and aggregate fitness function. The final result proposed by the algorithm was compared with the simulation program result and the measured result of a physical prototype of the antenna built in the laboratory. In the present study, the algorithm was analyzed with respect to their success degree in relation to four important characteristics of a self-organizing multiobjective GA: performance, flexibility, scalability and accuracy. At the end of the study, it was observed a time increase in algorithm execution in comparison to a common GA, due to the time required for the machine learning process. On the plus side, we notice a sensitive gain with respect to flexibility and accuracy of results, and a prosperous path that indicates directions to the algorithm to allow the optimization problems with "η" variables

Roteamento em Redes de Sensores Sem Fios Com Base Em Aprendizagem Por Reforço

The use of wireless sensor and actuator networks in industry has been increasing past few years, bringing multiple benefits compared to wired systems, like network flexibility and manageability. Such networks consists of a possibly large number of small and autonomous sensor and actuator devices with wireless communication capabilities. The data collected by sensors are sent directly or through intermediary nodes along the network to a base station called sink node. The data routing in this environment is an essential matter since it is strictly bounded to the energy efficiency, thus the network lifetime. This work investigates the application of a routing technique based on Reinforcement Learning s Q-Learning algorithm to a wireless sensor network by using an NS-2 simulated environment. Several metrics like energy consumption, data packet delivery rates and delays are used to validate de proposal comparing it with another solutions existing in the literature

Controle Robusto Aplicado a Conversor Buck-Boost em Sistemas Fotovoltaicos

The need to implement a software architecture that promotes the development of a SCADA supervisory system for monitoring industrial processes simulated with the flexibility of adding intelligent modules and devices such as CLP, according to the specifications of the problem, it was the motivation for this work. In the present study, we developed an intelligent supervisory system on a simulation of a distillation column modeled with Unisim. Furthermore, OLE Automation was used as communication between the supervisory and simulation software, which, with the use of the database, promoted an architecture both scalable and easy to maintain. Moreover, intelligent modules have been developed for preprocessing, data characteristics extraction, and variables inference. These modules were fundamentally based on the Encog software

Uso de funções de alívio para estimar o efeito de chaveamentos corretivos na eliminação de congestionamentos em sistemas de potência

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Projeto em FPGA de um controlador unificado para correção de fator de potência em retificadores boost bidirecionais monofásicos

The use of Field Programmable Gate Array (FPGA) for development of digital control strategies for power electronics applications has aroused a growing interest of many researchers. This interest is due to the great advantages offered by FPGA, which include: lower design effort, high performance and highly flexible prototyping. This work proposes the development and implementation of an unified one-cycle controller for boost CFP rectifier based on FPGA. This controller can be applied to a total of twelve converters, six inverters and six rectifiers defined by four single phase VSI topologies and three voltage modulation types. The topologies considered in this work are: full-bridge, interleaved full-bridge, half-bridge and interleaved half-bridge. While modulations are classified in bipolar voltage modulation (BVM), unipolar voltage modulation (UVM) and clamped voltage modulation (CVM). The proposed project is developed and prototyped using tools Matlab/Simulink® together with the DSP Builder library provided by Altera®. The proposed controller was validated with simulation and experimental results

Avaliação tribológica dos polímeros NBR, PTFE e PTFE gravitado em contato com aço AISI 52100

Low cost seals are made of NBR, Nitrile Butadiene Rubber, a family of unsaturated copolymers that is higher resistant to oils the more content of nitrile have in its composition, although lower its flexibility. In Petroleum Engineering, NBR seal wear can cause fluid leakage and environmental damages, promoting an increasing demand for academic knowledge about polymeric materials candidate to seals submitted to sliding contacts to metal surfaces. This investigation aimed to evaluate tribological responses of a commercial NBR, hardness 73 ± 5 Sh A, polytetrafluoroethylene (PTFE), hardness 60 ± 4 HRE and PTFE with graphite, 68 ± 6 HRE. The testings were performed on a sliding tribometer conceived to explore the tribological performance of stationary polymer plane coupons submitted to rotational cylinder contact surface of steel AISI 52100, 20 ± 1 HRC Hardness, under dry and lubricated (oil SAE 15W40) conditions. After screening testings, the normal load, relative velocity and sliding distance were 3.15 N, 0.8 m/s and 3.2 km, respectively. The temperatures were collected over distances of 3.0±0.5 mm and 750±50 mm far from the contact to evaluate the heating in this referential zone due to contact sliding friction by two thermocouples K type. The polymers were characterized through Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA). The wear mechanisms of the polymer surfaces were analyzed by Scanning Electron Microscopy (SEM) and EDS (Energy-Dispersive X-ray Spectroscopy). NBR referred to the higher values of heating, suggesting higher sliding friction. PTFE and PTFE with graphite showed lower heating, attributed to the delamination mechanism

Metodologia, Sistema de Codificação e Ferramenta de software para Modelagem de Móveis Modulados

On this research we investigated how new technologies can help the process of design and manufacturing of furniture in such small manufacturers in Rio Grande do Norte state. Google SketchUp, a 3D software tool, was developed in such a way that its internal structures are opened and can be accessed using SketchUp s API for Ruby and programs written in Ruby language (plugins). Using the concepts of the so-called Group Technology and the flexibility that enables adding new functionalities to this software, it was created a Methodology for Modeling of Furniture, a Coding System and a plugin for Google s tool in order to implement the Methodology developed. As resulted, the following facilities are available: the user may create and reuse the library s models over-and-over; reports of the materials manufacturing process costs are provided and, finally, detailed drawings, getting a better integration between the furniture design and manufacturing process

Método de Otimização Topológica em Estruturas Tridimensionais

The topology optimization problem characterize and determine the optimum distribution of material into the domain. In other words, after the definition of the boundary conditions in a pre-established domain, the problem is how to distribute the material to solve the minimization problem. The objective of this work is to propose a competitive formulation for optimum structural topologies determination in 3D problems and able to provide high-resolution layouts. The procedure combines the Galerkin Finite Elements Method with the optimization method, looking for the best material distribution along the fixed domain of project. The layout topology optimization method is based on the material approach, proposed by Bendsoe & Kikuchi (1988), and considers a homogenized constitutive equation that depends only on the relative density of the material. The finite element used for the approach is a four nodes tetrahedron with a selective integration scheme, which interpolate not only the components of the displacement field but also the relative density field. The proposed procedure consists in the solution of a sequence of layout optimization problems applied to compliance minimization problems and mass minimization problems under local stress constraint. The microstructure used in this procedure was the SIMP (Solid Isotropic Material with Penalty). The approach reduces considerably the computational cost, showing to be efficient and robust. The results provided a well defined structural layout, with a sharpness distribution of the material and a boundary condition definition. The layout quality was proporcional to the medium size of the element and a considerable reduction of the project variables was observed due to the tetrahedrycal element

Modificação superficial do tecido de malha de ácido polilatico (PLA) por tratamento plasma

Some fibrous materials, for having properties such as biocompatibility, strength and flexibility, are of great interest for medical and pharmaceutical applications. Among these materials, the fabric made from polylactic acid (PLA) has received special attention, and beside to present these features, is derived from biological source, antimicrobial and bioabsorbable. One of the limitations of PLA is its low wettability and capillarity. Due to this, it is necessary to perform surface modification of the knitted fabric, increasing its hydrophilicity. This work aims to realize the plasma treatment at low pressure in order to increase the surface energy of the polymer. The work was divided into three steps: i) Influence of the gas ratio (oxygen and nitrogen) in the surface modification of PLA fabric after the plasma treatment, ii) physical characterization and physicochemical surface tissue; iii) Evaluation of the effect from current and gas ratio in the capillary rise of tissues and iv) Study of capillarity in yarns and fabrics. The results showed that better gas ratios were the atmospheres: 100% oxygen; 100% nitrogen and 50% oxygen and 50% nitrogen. The surface characterization showed changes in topography and introduction of polar groups which increased the wettability of the fabric. In another part of this study, it was found that the atmosphere containing only nitrogen gas showed the most capillary rise to a current of 0.15 A. The results in capillary yarns and fabrics showed that the thread reached equilibrium in a time much less than the fabric to an atmosphere of 100% nitrogen and 0.15 A. Current Plasma technology was effective to increase the hydrophilicity of PLA fabric, providing surface characteristics favorable for future application in the biomedical field

Otimização do fresamento de roscas internas com a técnica de interpolação helicoidal

In machining of internal threads, dedicated tools, known as taps, are needed for each profile type, diameter, and low cutting speed values are used when compared to main machining processes. This restriction in the cutting speed is associated with the difficulty of synchronizing the tool s rotation speed and feed velocity in the process. This fact restricts the flexibility and makes machining lead times longer when manufacturing of components with threads is required. An alternative to the constraints imposed by the tap is the thread milling with helical interpolation technique. The technique is the fusion of two movements: rotation and helical interpolation. The tools may have different configurations: a single edge or multiple edges (axial, radial or both). However, thread milling with helical interpolation technique is relatively new and there are limited studies on the subject, a fact which promotes challenges to its wide application in the manufacturing shop floor. The objective of this research is determine the performance of different types of tools in the thread milling with helical interpolation technique using hardened steel workpieces. In this sense, four tool configurations were used for threading milling in AISI 4340 quenched and tempered steel (40 HRC). The results showed that climb cut promoted a greater number of machined threads, regardless of tool configuration. The upcut milling causes chippings in cutting edge, while the climb cutting promotes abrasive wear. Another important point is that increase in hole diameter by tool diameter ratio increases tool lifetime

A argumentação na petição inicial

This research investigates current sense effects at the use of linguistic resources of the argument in a corpus constituted by juridical pieces (Initial Petitions), that gave opportunity to actions originated from the Civil Special Court of the District of Currais Novos-RN. For this purpose it was established a relation between the Law and the Linguistics, mediated by the focus of the Argumentative Semantics, emphasizing, in a special way, the use of argumentative operators, which inserted in the own language, in its grammar, assume the orientation of the speech and the modalizers use, important mechanisms in the construction of the sense of the text and in the signalling in the way as that that one say is said,. This way, we began the investigation of that gender choosing as study object the section of the facts , that comprehends a part of Initial Petition where is explanted the narration of events that gave margin to the proposal for the Action. In face of the study object and the aim to be reached it was appealed, methodologically, to the notion of Rhetoric since from the classic antiquity to the emergence of the New present Rhetoric in Perelman and Olbrechts-Tyteca (2005) that, at the present time, is inserted in the studies of the Pragmatic connected to the central theses of the Ducrot s thinking (1977, 1980, 1987). Such referential allowed us to a better understanding about the production of the juridical speech on the part of the operators of the Law, as well as, to analyze in way wide the current sense effects from the use of argument linguistic marks the juridical speech. The data showed that such marks are indispensable elements to the construction of the textual web, particularly when in the range of the juridical argumentation, since they direct the speech for certain conclusions. However, we have observed that in the texts produced by the lawyers the use of those linguistic resources not always takes place in an appropriate way. The texts analyzed have also showed that it is possible to unmask, through the linguistic resources, the argumentative strategy employed by the authors for convincing of the magistrate, making evident that language is more than a system of signs, which it makes possible to see beyond the limit of the words and statements. Finally, we have verified that the categories analyzed, when used appropriately, are elements that engender argumentative maneuvers of effectiveness in the juridical text, being fundamental pieces which give argumentative strength the text, making the speech to move forward, not only the juridical, but the speech produced in any domain of the knowledge

O ensaio jornalístico na revista Veja: uma análise multidimensional

This work has as objective generality to make a multidimensional analysis in the genre journalistic assay, communicative genre that, beyond complex and multimodal, presents hybrid characteristics. Specifically, with the intention to propose defining criteria of the cited genre, this research looks for to establish differences and similarities between the assay and other genres of the same sphere, from the description and interpretation of used multimodal resources. The analysis of the formal, schematical and rhetorical resources identified in the formatting of the journalistic assay sample that the analyses are supported in the socio-semiotic and socio-rhetorical approaches. In the formal dimension, we contemplate elements that constitute design of the text, including the forms of representation from the typography, the colors, images, as well as the aspects communicative-linguistics: the modalization indices, the communicative operators and the category time; in the schematical dimension, we present the organizational structure, considering the rhetorical movements postulates for Swales (1990) and in the rhetorical dimension we observe the categories: who writes, for who it writes, on what it writes and where writes. The adopted methodologicals postulates are of qualitative nature and the procedure is documentary, data that in we are valid them written texts of this genre as analysis object. Corpus it is constituted by a composed sample for 14 extracted texts of a set of 173 propagated journalistic assays weekly for the magazine Veja, in the period between August of 2004 and January of 2008. The analysis of the data showed that the journalistic assay, object of this study, materializes through multiple symbolic representations and multiple subjects that turn since a small episode of the daily facts of great social relevance in the present time, of historical and cultural nature, nationwide or international. Used for the first time by Montaigne in 1580, to assign, in saying of the proper author, written fast on its life and historical events, which could nor be remembered later , the term `assay' was enriched with other specifications, of form to enclose the one that if they call scientific assay today, academic assay, journalistic assay and other types of specific assays. These denominations have to see with the enrollment of the members of diverse of practices communities, in virtue of the multiplicity of activities carried through in these spheres. The conclusions the one that we arrive had been the following ones: 1. the discursive genre is not a pure entity, in virtue of the multiplicity of situations where the sorts if insert in the social actions; 2. the institutions define the configuration of one definitive genre, also its proper assignment, since for backwards of all discursive genre a voice exists to discipline - institutional voice, and in the case of the assays for analyzed us, the institutional voice if it presents, really, as a defining trace; 3. the journalistic assay, for its multiple symbolic representations, multiple subjects and for passing explicit or implicit opinions of its author, resembles it other genres, being able, therefore, to be inserted in a colony of opinionatives genres

Análise textual dos discursos: responsabilidade enunciativa no texto jurídico

This investigation aims at describing, analyzing and interpreting the Commitment in Initial Petitions, which is a genre circumscribed in the judicial domain. For this purpose, we have chosen sections, facts as found and relevant law , sections of the petition, with the understanding that, in this way, respectively, the narration of events, which gives margin to the propositioning to the judicial action, and the exposition of the law that upholds the author s intention. We base our discussion on the field of Linguistics, more precisely, Textual Discourse Analysis (TDA), whose theoretical basis is derived from Textual Linguistics (TL) and Enunciative Linguistics. We foreground, particularly, the way in which the author of texts, objects of analysis, use discursive strategies that evidence ER. The relevance of this study, then, is in the formation of a critique of the judicial text, as it conceives of a dialogical approach to the point of view, raising not only questions about the way in which a linguistic instance conceives an object of discourse, but also considering questions of language inherent to technical writing and, in this aspect, contributing to the work of those operating in Law about the many ways ER is formed in the body of a petition. We selected two categories to analyze that, according to Adam (2011), characterize the degree of ER in the textual material of the propositional enunciations: the different types of representation of speech and the indications of profile of mediators. In this sense, with this task as an objective, we base our study regarding point of view on Rabatel (2003, 2009a, 2010) with relation to the enunciative approach, including the study of PDV in polyphonic and dialogical theoretical framework to study the ER from different types of speech representations that conceive forms of transmission of discourse and the role of the enunciating subject, mainly the responsibility and the prerogative by the propositional contents. In the same way, intending to study the indications of the mediator profiles, we observed the postulations of Guentchéva (1994, 1996), which develop the notion of mediative grammatical categories, of which permit the linguistic marking of distance and engagement of the enunciator with regard to the information expressed. The methodology we adopted was based on qualitative research, of an interpretive and introspective nature, in light of the fact that his study focuses on processes and strategies underlying language use. The corpus of the research is comprised of Initial Petitions, which gave rise to actions originating in the Civil Court of Currais Novos County RN. The data analysis shows that an object of discourse is always perspective oriented and presents the point of view of one or more enunciators. Consequently, the producer of a text, using the PDV of other enunciators, influences and establishes the argumentative orientation of the text. In the same way, it evidences the relevance of the use of mediated constructions in the judicial text, as they function as strategies attenuated to the responsibility of the producer of the text with what is said, and at the same time points to a discourse of authority through the entrance of the sources of law. Moreover, it reveals the documental and international importance of this practice, at the same time that it exposes the compositional and normative difficulties with regard to legal and linguistic aspects

Espectro das ondas de spin lineares e não-lineares em multicamadas magnéticas anisotrópicas

Conselho Nacional de Desenvolvimento Científico e Tecnológico

Efeito de três tecnicas de alongamento muscular sobre o torque e atividade eletromiográfica

PURPOSE: To examine the acute effects caused by three techniques for stretching the hamstrings muscle on the active concentric peak torque (PT), passive PT and electromyographic activity (EMG). METHODS: Sixty volunteers (mean ± SD age, 22.6 ± 3 years), height 1.64 ± 0.07m and body weight of 58 ± 8.6kg, were randomly allocated into 4 groups of 15 subjects: Control Group (CG) - 5 minutes at rest, Static Stretching Group (SG) - 2 x 30s; Hold-Relax Group (HRG) - 3 x 6s of isometric contraction of hamstrings interspersed by 10s of hamstrings stretching and agonist Hold-Relax Group (AHRG) - 3 x 6s of isometric contraction of the quadriceps interspersed by 10s of hamstrings stretching. Evaluation has been conducted preand post-intervention, which verified the active concentric PT, passive PT EMG activity of IT. The statistical inference was performed by testing intra and inter, significance level at 5%. RESULTS: After intervention, there was a reduction in passive PT on CG, accompanied by a reduction of EMG activity, and an increase in passive PT on SG and AHRG. There was no change in the active concentric PT, or change in EMG activity. CG showed an increase in angle of the PT active, while the other groups showed no change. CONCLUSION: The results suggest that the shortterm stretching: 1) causes acute increase in passive torque, since the muscle does not perform sub-maximal contraction, 2) does not change in electromyographic activity and active torque, ind ependent of the technique