993 resultados para Novas redes de acesso
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A Wireless Sensor Network (WSN) consists of distributed devices in an area in order to monitor physical variables such as temperature, pressure, vibration, motion and environmental conditions in places where wired networks would be difficult or impractical to implement, for example, industrial applications of difficult access, monitoring and control of oil wells on-shore or off-shore, monitoring of large areas of agricultural and animal farming, among others. To be viable, a WSN should have important requirements such as low cost, low latency, and especially low power consumption. However, to ensure these requirements, these networks suffer from limited resources, and eventually being used in hostile environments, leading to high failure rates, such as segmented routing, mes sage loss, reducing efficiency, and compromising the entire network, inclusive. This work aims to present the FTE-LEACH, a fault tolerant and energy efficient routing protocol that maintains efficiency in communication and dissemination of data.This protocol was developed based on the IEEE 802.15.4 standard and suitable for industrial networks with limited energy resources
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The great interest in nonlinear system identification is mainly due to the fact that a large amount of real systems are complex and need to have their nonlinearities considered so that their models can be successfully used in applications of control, prediction, inference, among others. This work evaluates the application of Fuzzy Wavelet Neural Networks (FWNN) to identify nonlinear dynamical systems subjected to noise and outliers. Generally, these elements cause negative effects on the identification procedure, resulting in erroneous interpretations regarding the dynamical behavior of the system. The FWNN combines in a single structure the ability to deal with uncertainties of fuzzy logic, the multiresolution characteristics of wavelet theory and learning and generalization abilities of the artificial neural networks. Usually, the learning procedure of these neural networks is realized by a gradient based method, which uses the mean squared error as its cost function. This work proposes the replacement of this traditional function by an Information Theoretic Learning similarity measure, called correntropy. With the use of this similarity measure, higher order statistics can be considered during the FWNN training process. For this reason, this measure is more suitable for non-Gaussian error distributions and makes the training less sensitive to the presence of outliers. In order to evaluate this replacement, FWNN models are obtained in two identification case studies: a real nonlinear system, consisting of a multisection tank, and a simulated system based on a model of the human knee joint. The results demonstrate that the application of correntropy as the error backpropagation algorithm cost function makes the identification procedure using FWNN models more robust to outliers. However, this is only achieved if the gaussian kernel width of correntropy is properly adjusted.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Diesel fuel is one of leading petroleum products marketed in Brazil, and has its quality monitored by specialized laboratories linked to the National Agency of Petroleum, Natural Gas and Biofuels - ANP. The main trial evaluating physicochemical properties of diesel are listed in the resolutions ANP Nº 65 of December 9th, 2011 and Nº 45 of December 20th, 2012 that determine the specification limits for each parameter and methodologies of analysis that should be adopted. However the methods used although quite consolidated, require dedicated equipment with high cost of acquisition and maintenance, as well as technical expertise for completion of these trials. Studies for development of more rapid alternative methods and lower cost have been the focus of many researchers. In this same perspective, this work conducted an assessment of the applicability of existing specialized literature on mathematical equations and artificial neural networks (ANN) for the determination of parameters of specification diesel fuel. 162 samples of diesel with a maximum sulfur content of 50, 500 and 1800 ppm, which were analyzed in a specialized laboratory using ASTM methods recommended by the ANP, with a total of 810 trials were used for this study. Experimental results atmospheric distillation (ASTM D86), and density (ASTM D4052) of diesel samples were used as basic input variables to the equations evaluated. The RNAs were applied to predict the flash point, cetane number and sulfur content (S50, S500, S1800), in which were tested network architectures feed-forward backpropagation and generalized regression varying the parameters of the matrix input in order to determine the set of variables and the best type of network for the prediction of variables of interest. The results obtained by the equations and RNAs were compared with experimental results using the nonparametric Wilcoxon test and Student's t test, at a significance level of 5%, as well as the coefficient of determination and percentage error, an error which was obtained 27, 61% for the flash point using a specific equation. The cetane number was obtained by three equations, and both showed good correlation coefficients, especially equation based on aniline point, with the lowest error of 0,816%. ANNs for predicting the flash point and the index cetane showed quite superior results to those observed with the mathematical equations, respectively, with errors of 2,55% and 0,23%. Among the samples with different sulfur contents, the RNAs were better able to predict the S1800 with error of 1,557%. Generally, networks of the type feedforward proved superior to generalized regression.
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The solidary economy as the organization of production, alternative to the capitalist economy provides new forms of organization and social behavior, that, in the sight of geography, it is shown by the different territory uses. The territory assume new meanings that, influenced by the Solidary Economy movement, tries to reach for new ways of acting that differ from social order already stablished. However, the different uses show themselves in a more complex and contradictory way, given that, in solidary undertakings, different corporative agents start to act, the State being a last resource on this process. Given this reality, our goal on the present paper is to analyze the different uses of the territory from the rural economic solidary undertakings and the relationship it establishes to the different agents involved on the socio-territorial dynamics on Rio Grande do Norte. Starting from a study that contemplates the territorial organization forms and contents of the analyzed phenomena, the methodology utilized for this research is based on a bibliographic review, with authors from the geography and areas related to the Solidary Economy, besides the use of secondary data, acquired from official offices such as SIES and IBGE, from the documented research, SENAES and field interviews conducted with local solidary undertakings. The results obtained in the study reveal the complexity of the agricultural use of the territory by Solidary Economy on the RN, while a resource of intensified use, from the state actions and important economical agents, and regulating the use while shelter, that marginalize solidary workers, making them subdued to the hegemonic logic. Therefore, we can infer that the solidary economy, despite its image of new form of organization between agricultural workers, given the expressivity of the rural solidary undertakings presented on RN, it hasn’t shown a full social development as an instrument of reproduction and emancipation of the associates. Nevertheless, the undertakings articulated in nets excel, even when considering its punctual and residual form. The given contradictions show that it is necessary to fortify the building of the solidary economy as being horizontal and popular based for it to have strength to surpass the regulative actions of the capitalist state and ownership created by the Capital.
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Objective Based on the system of reference and counter-reference and comprehensiveness in oral health care, we aimed to examine ways of refering users to Specialized Dental Care Centers (SDCC) and the interface between them and Primary Care. Methods This is a cross-sectional study carried out with users and dentists of SDCC in a metropolitan region of Northeast of Brazil. Analyses were descriptive, and the association test was done with chi-square. Results Six forms of entry to specialized service were identified: free demand (13.8 %) and reference by the Primary Care dentist (63.2 %) were most frequent. Users referred by the basic health unit dentist had more interest in making a counter-reference than the others (p<0.001, PR=4.65, 95 % CI: 2.74 to 7.91), while individuals without this referral had 1.49 times more difficulty obtaining care (95 % CI: 1.02 to 2.17). Referral procedures are a decisive factor for counter-references. However, the high demand for primary care services and the short supply these services can offer in the face of needs make SDCC performance difficult. Conclusion The analysis of oral health practices from the perspective of network modeling points to the service's need to establish protocols for regulation in a bid to improve access to and the quality of care provided.
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Objective Based on the system of reference and counter-reference and comprehensiveness in oral health care, we aimed to examine ways of refering users to Specialized Dental Care Centers (SDCC) and the interface between them and Primary Care. Methods This is a cross-sectional study carried out with users and dentists of SDCC in a metropolitan region of Northeast of Brazil. Analyses were descriptive, and the association test was done with chi-square. Results Six forms of entry to specialized service were identified: free demand (13.8 %) and reference by the Primary Care dentist (63.2 %) were most frequent. Users referred by the basic health unit dentist had more interest in making a counter-reference than the others (p<0.001, PR=4.65, 95 % CI: 2.74 to 7.91), while individuals without this referral had 1.49 times more difficulty obtaining care (95 % CI: 1.02 to 2.17). Referral procedures are a decisive factor for counter-references. However, the high demand for primary care services and the short supply these services can offer in the face of needs make SDCC performance difficult. Conclusion The analysis of oral health practices from the perspective of network modeling points to the service's need to establish protocols for regulation in a bid to improve access to and the quality of care provided.
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Wireless Communication is a trend in the industrial environment nowadays and on this trend, we can highlight the WirelessHART technology. In this situation, it is natural the search for new improvements in the technology and such improvements can be related directly to the routing and scheduling algorithms. In the present thesis, we present a literature review about the main specific solutions for Routing and scheduling for WirelessHART. The thesis also proposes a new scheduling algorithm called Flow Scheduling that intends to improve superframe utilization and flexibility aspects. For validation purposes, we develop a simulation module for the Network Simulator 3 (NS-3) that models aspects like positioning, signal attenuation and energy consumption and provides an link individual error configuration. The module also allows the creation of the scheduling superframe using the Flow and Han Algorithms. In order to validate the new algorithms, we execute a series of comparative tests and evaluate the algorithms performance for link allocation, delay and superframe occupation. In order to validate the physical layer of the simulation module, we statically configure the routing and scheduling aspects and perform reliability and energy consumption tests using various literature topologies and error probabilities.
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Wireless Communication is a trend in the industrial environment nowadays and on this trend, we can highlight the WirelessHART technology. In this situation, it is natural the search for new improvements in the technology and such improvements can be related directly to the routing and scheduling algorithms. In the present thesis, we present a literature review about the main specific solutions for Routing and scheduling for WirelessHART. The thesis also proposes a new scheduling algorithm called Flow Scheduling that intends to improve superframe utilization and flexibility aspects. For validation purposes, we develop a simulation module for the Network Simulator 3 (NS-3) that models aspects like positioning, signal attenuation and energy consumption and provides an link individual error configuration. The module also allows the creation of the scheduling superframe using the Flow and Han Algorithms. In order to validate the new algorithms, we execute a series of comparative tests and evaluate the algorithms performance for link allocation, delay and superframe occupation. In order to validate the physical layer of the simulation module, we statically configure the routing and scheduling aspects and perform reliability and energy consumption tests using various literature topologies and error probabilities.
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The Artificial Neural Networks (ANN), which is one of the branches of Artificial Intelligence (AI), are being employed as a solution to many complex problems existing in several areas. To solve these problems, it is essential that its implementation is done in hardware. Among the strategies to be adopted and met during the design phase and implementation of RNAs in hardware, connections between neurons are the ones that need more attention. Recently, are RNAs implemented both in application specific integrated circuits's (Application Specific Integrated Circuits - ASIC) and in integrated circuits configured by the user, like the Field Programmable Gate Array (FPGA), which have the ability to be partially rewritten, at runtime, forming thus a system Partially Reconfigurable (SPR), the use of which provides several advantages, such as flexibility in implementation and cost reduction. It has been noted a considerable increase in the use of FPGAs for implementing ANNs. Given the above, it is proposed to implement an array of reconfigurable neurons for topologies Description of artificial neural network multilayer perceptrons (MLPs) in FPGA, in order to encourage feedback and reuse of neural processors (perceptrons) used in the same area of the circuit. It is further proposed, a communication network capable of performing the reuse of artificial neurons. The architecture of the proposed system will configure various topologies MLPs networks through partial reconfiguration of the FPGA. To allow this flexibility RNAs settings, a set of digital components (datapath), and a controller were developed to execute instructions that define each topology for MLP neural network.
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The Artificial Neural Networks (ANN), which is one of the branches of Artificial Intelligence (AI), are being employed as a solution to many complex problems existing in several areas. To solve these problems, it is essential that its implementation is done in hardware. Among the strategies to be adopted and met during the design phase and implementation of RNAs in hardware, connections between neurons are the ones that need more attention. Recently, are RNAs implemented both in application specific integrated circuits's (Application Specific Integrated Circuits - ASIC) and in integrated circuits configured by the user, like the Field Programmable Gate Array (FPGA), which have the ability to be partially rewritten, at runtime, forming thus a system Partially Reconfigurable (SPR), the use of which provides several advantages, such as flexibility in implementation and cost reduction. It has been noted a considerable increase in the use of FPGAs for implementing ANNs. Given the above, it is proposed to implement an array of reconfigurable neurons for topologies Description of artificial neural network multilayer perceptrons (MLPs) in FPGA, in order to encourage feedback and reuse of neural processors (perceptrons) used in the same area of the circuit. It is further proposed, a communication network capable of performing the reuse of artificial neurons. The architecture of the proposed system will configure various topologies MLPs networks through partial reconfiguration of the FPGA. To allow this flexibility RNAs settings, a set of digital components (datapath), and a controller were developed to execute instructions that define each topology for MLP neural network.
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Cryptography is the main form to obtain security in any network. Even in networks with great energy consumption restrictions, processing and memory limitations, as the Wireless Sensors Networks (WSN), this is no different. Aiming to improve the cryptography performance, security and the lifetime of these networks, we propose a new cryptographic algorithm developed through the Genetic Programming (GP) techniques. For the development of the cryptographic algorithm’s fitness criteria, established by the genetic GP, nine new cryptographic algorithms were tested: AES, Blowfish, DES, RC6, Skipjack, Twofish, T-DES, XTEA and XXTEA. Starting from these tests, fitness functions was build taking into account the execution time, occupied memory space, maximum deviation, irregular deviation and correlation coefficient. After obtaining the genetic GP, the CRYSEED and CRYSEED2 was created, algorithms for the 8-bits devices, optimized for WSNs, i.e., with low complexity, few memory consumption and good security for sensing and instrumentation applications.
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Cryptography is the main form to obtain security in any network. Even in networks with great energy consumption restrictions, processing and memory limitations, as the Wireless Sensors Networks (WSN), this is no different. Aiming to improve the cryptography performance, security and the lifetime of these networks, we propose a new cryptographic algorithm developed through the Genetic Programming (GP) techniques. For the development of the cryptographic algorithm’s fitness criteria, established by the genetic GP, nine new cryptographic algorithms were tested: AES, Blowfish, DES, RC6, Skipjack, Twofish, T-DES, XTEA and XXTEA. Starting from these tests, fitness functions was build taking into account the execution time, occupied memory space, maximum deviation, irregular deviation and correlation coefficient. After obtaining the genetic GP, the CRYSEED and CRYSEED2 was created, algorithms for the 8-bits devices, optimized for WSNs, i.e., with low complexity, few memory consumption and good security for sensing and instrumentation applications.
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Arquitetura em cidades “sempre novas”: modernismo, projeto e patrimônio. Com essa chamada, a 4ª edição do encontro DOCOMOMO Norte-Nordeste, realizado na Universidade Federal do Rio Grande do Norte, em Natal, no período de 29 de maio a 02 de junho de 2012, reuniu um conjunto de trabalhos, mesas e conferências para pensar o processo de renovação arquitetônica e urbana de nossas cidades partindo da questão central de que o gosto pelo novo, pela novidade, torna rapidamente obsoleto aquilo que, quando surgiu, também era novo, moderno. O encontro contemplou uma diversidade de enfoques distribuída em três eixos temáticos:1) A arquitetura moderna como projeto; 2) experiências de conservação e transformação; e 3)narrativas historiográficas, na observação da especificidade da arquitetura, do urbanismo e do paisagismo no Brasil. Este livro, se organiza segundo cinco abordagens que estão subjacentes aos três eixos temáticos acima mencionados: a) trajetórias profissionais; b) a presença modernista em cidades brasileiras; c) a documentação, conservação, projeto e restauro; d) reflexões sobre a produção modernista e, finalmente, e) a tecnologia e desempenho. Para cada abordagem, foram selecionados alguns trabalhos representativos apresentados na ocasião. Espera-se contribuir, com esse livro, para o debate sobre a aparente – ou, para muitos, real – contradição entre a necessidade de renovação constante de nosso ambiente construído – afinal, a arquitetura e a cidade são por natureza dinâmicas – e a necessidade de preservação, particularmente do legado modernista inscrito em nossa paisagem urbana, ameaçado de extinção pelo descaso, pelo abandono ou pela transformação descabida.
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Arquitetura em cidades “sempre novas”: modernismo, projeto e patrimônio. Com essa chamada, a 4ª edição do encontro DOCOMOMO Norte-Nordeste, realizado na Universidade Federal do Rio Grande do Norte, em Natal, no período de 29 de maio a 02 de junho de 2012, reuniu um conjunto de trabalhos, mesas e conferências para pensar o processo de renovação arquitetônica e urbana de nossas cidades partindo da questão central de que o gosto pelo novo, pela novidade, torna rapidamente obsoleto aquilo que, quando surgiu, também era novo, moderno. O encontro contemplou uma diversidade de enfoques distribuída em três eixos temáticos:1) A arquitetura moderna como projeto; 2) experiências de conservação e transformação; e 3)narrativas historiográficas, na observação da especificidade da arquitetura, do urbanismo e do paisagismo no Brasil. Este livro, se organiza segundo cinco abordagens que estão subjacentes aos três eixos temáticos acima mencionados: a) trajetórias profissionais; b) a presença modernista em cidades brasileiras; c) a documentação, conservação, projeto e restauro; d) reflexões sobre a produção modernista e, finalmente, e) a tecnologia e desempenho. Para cada abordagem, foram selecionados alguns trabalhos representativos apresentados na ocasião. Espera-se contribuir, com esse livro, para o debate sobre a aparente – ou, para muitos, real – contradição entre a necessidade de renovação constante de nosso ambiente construído – afinal, a arquitetura e a cidade são por natureza dinâmicas – e a necessidade de preservação, particularmente do legado modernista inscrito em nossa paisagem urbana, ameaçado de extinção pelo descaso, pelo abandono ou pela transformação descabida.