870 resultados para auto-regressive


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This work presents a set of intelligent algorithms with the purpose of correcting calibration errors in sensors and reducting the periodicity of their calibrations. Such algorithms were designed using Artificial Neural Networks due to its great capacity of learning, adaptation and function approximation. Two approaches willbe shown, the firstone uses Multilayer Perceptron Networks to approximate the many shapes of the calibration curve of a sensor which discalibrates in different time points. This approach requires the knowledge of the sensor s functioning time, but this information is not always available. To overcome this need, another approach using Recurrent Neural Networks was proposed. The Recurrent Neural Networks have a great capacity of learning the dynamics of a system to which it was trained, so they can learn the dynamics of a sensor s discalibration. Knowingthe sensor s functioning time or its discalibration dynamics, it is possible to determine how much a sensor is discalibrated and correct its measured value, providing then, a more exact measurement. The algorithms proposed in this work can be implemented in a Foundation Fieldbus industrial network environment, which has a good capacity of device programming through its function blocks, making it possible to have them applied to the measurement process

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Ceramic substrates have been investigated by researchers around the world and has achieved a high interest in the scientific community, because they had high dielectric constants and excellent performance in the structures employed. Such ceramics result in miniaturized structures with dimensions well reduced and high radiation efficiency. In this work, we have used a new ceramic material called lead zinc titanate in the form of Zn0,8Pb0,2TiO3, capable of being used as a dielectric substrate in the construction of various structures of antennas. The method used in constructing the ceramic combustion synthesis was Self- Sustained High Temperature (SHS - "Self-Propagating High-Temperature Synthesis") which is defined as a process that uses highly exothermic reactions to produce various materials. Once initiated the reaction area in the reaction mixture, the heat generated is sufficient to become self-sustaining combustion in the form of a wave that propagates converting the reaction mixture into the product of interest. Were analyzed aspects of the formation of the composite Zn0,8Pb0,2TiO3 by SHS powders and characterized. The analysis consisted of determining the parameters of the reaction for the formation of the composite, as the ignition temperature and reaction mechanisms. The production of composite Zn0,8Pb0,2TiO3 by SHS performed in the laboratory, was the result of a total control of combustion temperature and after obtaining the powder began the development of ceramics. The product was obtained in the form of regular, alternating layers of porous ceramics and was obtained by uniaxial pressing. 10 The product was characterized by analysis of dilatometry, X-ray diffraction analysis and scanning electron microscopy. One of the contributions typically defined in this work is the development of a new dielectric material, nevertheless presented previously in the literature. Therefore, the structures of the antennas presented in this work consisted of new dielectric ceramics based Zn0,8Pb0,2TiO3 usually used as dielectric substrate. The materials produced were characterized in the microwave range. These are dielectrics with high relative permittivity and low loss tangent. The Ansoft HFSS, commercial program employee, using the finite element method, and was used for analysis of antennas studied in this work

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Image compress consists in represent by small amount of data, without loss a visual quality. Data compression is important when large images are used, for example satellite image. Full color digital images typically use 24 bits to specify the color of each pixel of the Images with 8 bits for each of the primary components, red, green and blue (RGB). Compress an image with three or more bands (multispectral) is fundamental to reduce the transmission time, process time and record time. Because many applications need images, that compression image data is important: medical image, satellite image, sensor etc. In this work a new compression color images method is proposed. This method is based in measure of information of each band. This technique is called by Self-Adaptive Compression (S.A.C.) and each band of image is compressed with a different threshold, for preserve information with better result. SAC do a large compression in large redundancy bands, that is, lower information and soft compression to bands with bigger amount of information. Two image transforms are used in this technique: Discrete Cosine Transform (DCT) and Principal Component Analysis (PCA). Primary step is convert data to new bands without relationship, with PCA. Later Apply DCT in each band. Data Loss is doing when a threshold discarding any coefficients. This threshold is calculated with two elements: PCA result and a parameter user. Parameters user define a compression tax. The system produce three different thresholds, one to each band of image, that is proportional of amount information. For image reconstruction is realized DCT and PCA inverse. SAC was compared with JPEG (Joint Photographic Experts Group) standard and YIQ compression and better results are obtain, in MSE (Mean Square Root). Tests shown that SAC has better quality in hard compressions. With two advantages: (a) like is adaptive is sensible to image type, that is, presents good results to divers images kinds (synthetic, landscapes, people etc., and, (b) it need only one parameters user, that is, just letter human intervention is required

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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

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Self-organizing maps (SOM) are artificial neural networks widely used in the data mining field, mainly because they constitute a dimensionality reduction technique given the fixed grid of neurons associated with the network. In order to properly the partition and visualize the SOM network, the various methods available in the literature must be applied in a post-processing stage, that consists of inferring, through its neurons, relevant characteristics of the data set. In general, such processing applied to the network neurons, instead of the entire database, reduces the computational costs due to vector quantization. This work proposes a post-processing of the SOM neurons in the input and output spaces, combining visualization techniques with algorithms based on gravitational forces and the search for the shortest path with the greatest reward. Such methods take into account the connection strength between neighbouring neurons and characteristics of pattern density and distances among neurons, both associated with the position that the neurons occupy in the data space after training the network. Thus, the goal consists of defining more clearly the arrangement of the clusters present in the data. Experiments were carried out so as to evaluate the proposed methods using various artificially generated data sets, as well as real world data sets. The results obtained were compared with those from a number of well-known methods existent in the literature

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O desenvolvimento de um processo democrático de avaliação institucional na UNESP, uma universidade multi-campus, envolveu três desafios: garantir o envolvimento de grupos representativos da comunidade no processo de avaliação; atribuir poder e responsabilidade a cada setor acadêmico e administrativo no processo de avaliação; criar uma cultura de auto-avaliação e reflexão que possibilitasse debate crítico e auto-gestão dos projetos acadêmicos. Com base nos termos de referência estabelecidos pela comunidade a CPA desenvolveu uma metodologia de avaliação democrática e investigativa, orientada para a auto-gestão e de natureza quali-quantitativa. Fundamentada em três enfoques teóricos de avaliação, o democrático, o de tomada de decisão e o crítico o processo envolveu três funções: a diagnóstica, a formativo-reflexiva e a de revisão crítica. Atualmente os usos dos resultados da avaliação para orientar políticas e decisões acadêmicas, especialmente nos cursos de graduação, evidenciam avanços no processo de internalização de cultura de avaliação orientada para auto-gestão.

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This dissertation, entitled O Auto da Morte e da Vida: A escrita barroca de João Cabral de Melo Neto, has the aim of analising, interpreting, in a baroque perspective, Cabral s writing in the poem/play Morte e vida severina Auto de Natal Pernambucano, taking as basis the theories of Eugênio D´Ors, Severo Sarduy, Omar Calabrase, Lezama Lima, Afonso Ávila, Affonso Romano de Sant´Anna and others cited in the body of this work. During the analisys we feature confluences, relations, similarities, identification between the Baroque of the counter reformation and the modern Baroque or Neobaroque. We seek to comprehend the baroque which is new in the XX century and Cabral s poetry as an element of the contemporaneity, by updating the concept of the Baroque in the 1600s, when it is detected in its purest characteristic in human relation (the life of the Northwestern brazilian) through an intangible reality (the death). The Baroque as a cultural summary of a period of instability and transformation, with the power of dismantling an already established poetry. The fight between words and things, language and reality

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This study approach the Jorge Luis Borges s prose of fiction under the perspective of mimesis and the self-reflexivity. The hypothesis is that the Aleph is a central symbol of the Borges s fictional universe. The rewriting and the retake of this symbol along of his work entail to a reflection about the possibilities and the limits of mimesis. This study is divided in three parts which contain two chapters. The first part Bibliographic revision and conceptual fundaments of inquiry discuss the critical fortune of author (Chapter 1) and the concepts that will give sustentation to the inquiry (Chapter 2). The second part About the Borges s aesthetic project sketch out the literary project defended by Borges that is his conception of the literature and his ideological matrix (Chapter 3) beside his anti-psychologism and his nostalgia of epos (Chapter 4). The third and last part is entitled The Aleph and his doubles. In the chapter 5 this study analyses the short story El Aleph and consider its centrality on the Borges s work. The argument that is on this short story Borges elaborates a reflection about mimesis. In the chapter 6, on the same hand, four short stories will be analysed: Funes el memorioso ; El Libro de Arena ; El evangelio según Marcos and Del rigor en la ciencia . The conclusion that is the Borges s literature is self-awake of its process as such demonstrate its parodic sense and its bookish origin. Hence, the Borges s literature overlapping the mimetic crisis of language and challenge the limits between fiction and reality. However, it doesn t surrender to the nihilist perspective that is closing of literature to the world

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This work is a detailed study of self-similar models for the expansion of extragalactic radio sources. A review is made of the definitions of AGN, the unified model is discussed and the main characteristics of double radio sources are examined. Three classification schemes are outlined and the self-similar models found in the literature are studied in detail. A self-similar model is proposed that represents a generalization of the models found in the literature. In this model, the area of the head of the jet varies with the size of the jet with a power law with an exponent γ. The atmosphere has a variable density that may or may not be spherically symmetric and it is taken into account the time variation of the cinematic luminosity of the jet according to a power law with an exponent h. It is possible to show that models Type I, II and III are particular cases of the general model and one also discusses the evolution of the sources radio luminosity. One compares the evolutionary curves of the general model with the particular cases and with the observational data in a P-D diagram. The results show that the model allows a better agreement with the observations depending on the appropriate choice of the model parameters.

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The aging process modifies various systems in the body, leading to changes in mobility, balance and muscle strength. This can cause a drop in the elderly, or not changing the perceived self-efficacy in preventing falls. Objective: To compare the mobility, body balance and muscle performance according to self-efficacy for falls in community-dwelling elderly. Methods: A cross-sectional comparative study with 63 older (65-80 years) community. Were evaluated for identification data and sociodemographic, cognitive screening using the Mini Mental State Examination (MMSE), effective for the fall of Falls Efficacy Scale International Brazil (FES-I-BRAZIL), Mobility through the Timed Up and Go Test , the balance Berg Balance Scale (BBS) and the Modified Clinical Test tests of Sensory Interaction on Balance (mCTSIB), tandem walk (TW) and Sit to Stand (STS) of the Balance Master® System. Finally, muscle performance by using isokinetic dynamometry. Statistical analysis was performed Student t test for comparison between groups, with p value ≤ 0.05. Results: Comparing the elderly with low-efficacy for falls with high-efficacy for falls, we found significant differences only for the variable Timed Up and Go Test (p = 0.04). With regard to data on balance tests were significant differences in the speed of oscillation firm surface eyes open modified Clinical Test of Sensory Interaction on Test of Balance (p = 0.01). Variables to isokinetic dynamometry were no significant differences in movement knee extension, as regards the variables peak torque (p = 0.04) and power (p = 0.03). Conclusion: The results suggest that, compared to older community with low-and high-efficacy for falls, we observed differences in variables related to mobility, balance and muscle function

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The objective of this work was to evaluate the buffering effect of sodium bicarbonate (NaHCO3), used in the levels of: 0, 0.7, 1.4 and 2.1% of dry matter, on the in situ degradation of corn and cottonseed meal. A diet with 60% autohidrolised sugar bagasse (BAH) and 40% of concentrate was used, plus urea, minerals and limestone. The rations was calculated to allow 300g of daily gain. After 20 days of adaptation to the treatment (levels of NaHCO3), 5g of each feed was incubated in the rumen of four bovines for 3, 6, 12, 24 and 48 hours, using naylon bag with size of 7,5 x 17,5 cm with pores of 36 micras. A randomized blocks design with four treatment (levels of NaHCO3) were used. The buffer affected the in situ dry matter degradation, whose means were 49.68; 63,10; 67,71; and 60,85% and 25.89; 30.88; 33.48 and; 31.02% for the corn and cottonseed meal, respectively. The level of 1.4% of NaHCO3 provided the highest value of degradability, which did not differ from the 0.7% and 2.1% levels, for the corn. The degradability of protein was not affected by the treatments.

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Marmosets, Callithrix jacchus, are strictly diurnal animals. The motor activity rhythmicity is generated by the circadian timing system and is modulated by environmental factors, mainly by photic stimuli that compose the light-dark cycle. Photic stimuli can reset the biological oscilators changing activity motor pattern, by a mechanism called entrainment. Otherwise, light can act directly on expressed rhythm, without act on the biological oscillators, promoting the masking. Thus, photic stimuli can synchronize the circadian activity rhythm (CAR) by two distinct mechanisms, acting isolated or at a combined way. Among the elements that can influence photic synchronization, the duration and time of photic exposure is pointed out. If in the natural environment the marmoset can choose places of different intensity illumination and is synchronized to light-dark cycle (LD), how the photic synchronization mechanism can be evaluated in laboratory by light self-selection? With objective to response this question, four adult male marmosets were studied at two conditions: with and without sleeping box. The animals were submitted to a LD cycle (12:12/ 350:2 lx) and constant light (LL: 350 lx) conditions in individual cages with an opaque sleeping box, that permitted the light self-selection. At the room, the temperature was 25.6 ºC (± 0.3 ºC) and humidity was 78.7 (± 5%). The motor activity was recorded at 5 min bins by infrared movement sensors installed at the top of the cages. The motor activity profile was distinct at the two conditions: without the sleeping box protection against light, the activity frequency was higher at CT 11-12 (ANOVA; F(3.23) = 62.27; p < 0.01). Also, the duration of the active phase (α) was prolonged of about 1 h (t test, p < 0.05) and the animals showed a significant delay on the activity onset and offset (t test, p < 0.05) and at the acrophase (confidence intervals of 5%) of CAR. In LL, the light continuous exposure prolonged the active phase and influenced the endogenous expression of the circadian activity rhythm period. From the result analysis, it is concluded that the light self-selection can modify several parameters of CAR in marmosets, allowing the study of the synchronization mechanism using the burrow model. Thus, without sleeping box there was a phase delay between the CAR and LD (entrainment) and an increase of activity near lights off (positive masking). Furthermore, in LL, the light continuous exposure modifies α and the endogenous expression of CAR. It is suggested that the light self-selection might be take into account at investigations that evaluate the biological rhythmicity in marmosets

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This research investigates the self-esteem of children who suffered physical violence by family members. Seven children took part in the research: three boys and four girls, aged between six and twelve years old. The analysis were done from the constructed data obtained from: semi-structured interview, activities about human feelings, activities that included facial expressions, unfinished phrases, Pinocchio s story, a drawing of a family and a drawing of their own family. Data were analyzed from the Content Analysis. The Thematic Units were: violence, intrafamily violence, and self-esteem. The synthesis of the categories studied evidenced that the physical violence and the psychological violence present in the lives of children affect the positive development of their self-concept and, consequently, of their self-esteem. Among the results, we emphasize some negative feelings that are present in children s lives such as fear, a sense of guilt, and sadness, arising out of the situations of violence they have experienced

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The objective of this work was to evaluate the buffering effects, using sodium bicarbonate (NaHCO3) at the levels: 0; 0.7; 1.4; and 2.1% of dry matter, on the in situ degradation of autohidrolised sugar-cane bagasse. A diet was used with 60% autohidrolised sugar bagasse (AHB) and 40% of concentrate, plus urea, minerals and limestone. The rations was calculated to allow 300g of daily gain. After 20 days adaptation to the treatment (level of NaHCO3), 5 g of AWE was incubated on rumen of four bovines for 3, 6, 12, 24 and 48 hours, using naylon bag measuring 7,5 x 17,5 cm with pores of 36 micras. It was used a randomized blocks design with four treatments (NaHCO3) and four replications(animals). For the calculations of the protein degradation, it was considered the soluble fraction in water plus the degraded fraction in the same proportion as for the neutral detergent fiber (NDF). It was observed that the buffer did not affect the degradability in situ of AHB, whose averages in 48 hours of incubation for dry matter, organic matter, crude protein and neutral detergente fiber (NDF) were 34.83; 36.90; 55.40; and 25.56%, respectively.