Implementação e análise de desempenho dos protocolos de criptografia neural e Diffie-Hellman em sistemas RFID utilizando uma plataforma embarcada

RFID (Radio Frequency Identification) identifies object by using the radio frequency which is a non-contact automatic identification technique. This technology has shown its powerful practical value and potential in the field of manufacturing, retailing, logistics and hospital automation. Unfortunately, the key problem that impacts the application of RFID system is the security of the information. Recently, researchers have demonstrated solutions to security threats in RFID technology. Among these solutions are several key management protocols. This master dissertations presents a performance evaluation of Neural Cryptography and Diffie-Hellman protocols in RFID systems. For this, we measure the processing time inherent in these protocols. The tests was developed on FPGA (Field-Programmable Gate Array) platform with Nios IIr embedded processor. The research methodology is based on the aggregation of knowledge to development of new RFID systems through a comparative analysis between these two protocols. The main contributions of this work are: performance evaluation of protocols (Diffie-Hellman encryption and Neural) on embedded platform and a survey on RFID security threats. According to the results the Diffie-Hellman key agreement protocol is more suitable for RFID systems

Desenvolvimento de um ressoador retangular de fenda com múltiplas camadas de substrato e com utilização de material PBG para sistema de comunicação sem fio

In the globalized world modern telecommunications have assumed key role within the company, causing a large increase in demand for the wireless technology of communication, which has been happening in recent years have greatly increased the number of applications using this technology. Due to this demand, new materials are developed to enable new control mechanisms and propagation of electromagnetic waves. The research to develop new technologies for wireless communication presents a multidisciplinary study that covers from the new geometries for passive antennas, active up to the development of materials for devices that improve the performance at the frequency range of operation. Recently, planar antennas have attracted interest due to their characteristics and advantages when compared with other types of antennas. In the area of mobile communications the need for antennas of this type has become increasingly used, due to intensive development, which needs to operate in multifrequency antennas and broadband. The microstrip antennas have narrow bandwidth due to the dielectric losses generated by irradiation. Another limitation is the degradation of the radiation pattern due to the generation of surface waves in the substrate. Some techniques have been developed to minimize this limitation of bandwidth, such as the study of type materials PBG - Photonic Band Gap, to form the dielectric material. This work has as main objective the development project of a slot resonator with multiple layers and use the type PBG substrate, which carried out the optimization from the numerical analysis and then designed the device initially proposed for the band electromagnetic spectrum between 3-9 GHz, which basically includes the band S to X. Was used as the dielectric material RT/Duroid 5870 and RT/Duroid 6010.LM where both are laminated ceramic-filled PTFE dielectric constants 2.33 and 10.2, respectively. Through an experimental investigation was conducted an analysis of the simulated versus measured by observing the behavior of the radiation characteristics from the height variation of the dielectric multilayer substrates. We also used the LTT method resonators structures rectangular slot with multiple layers of material photonic PBG in order to obtain the resonance frequency and the entire theory involving the electromagnetic parameters of the structure under consideration. xviii The analysis developed in this work was performed using the method LTT - Transverse Transmission Line, in the field of Fourier transform that uses a component propagating in the y direction (transverse to the real direction of propagation z), thus treating the general equations of the fields electric and magnetic and function. The PBG theory is applied to obtain the relative permittivity of the polarizations for the sep photonic composite substrates material. The results are obtained with the commercial software Ansoft HFSS, used for accurate analysis of the electromagnetic behavior of the planar device under study through the Finite Element Method (FEM). Numerical computational results are presented in graphical form in two and three dimensions, playing in the parameters of return loss, frequency of radiation and radiation diagram, radiation efficiency and surface current for the device under study, and have as substrates, photonic materials and had been simulated in an appropriate computational tool. With respect to the planar device design study are presented in the simulated and measured results that show good agreement with measurements made. These results are mainly in the identification of resonance modes and determining the characteristics of the designed device, such as resonant frequency, return loss and radiation pattern

Classes sociais e eleições presidenciais no Brasil contemporâneo (2002-2010)

This work aims to analyze, in terms of class, the social composition of the constituency of the presidential candidates of the Workers Party in 2002, 2006 and 2010 elections. Such research object is constructed from a preliminary critical debate with recent Brazilian electoral studies, especially the literature on the infl uence of social programs on voting and Singer’s formulations about the lulismo phenomenon. Incorporating advances and pointing out gaps in such research efforts, is formulated a roadmap for empirical research constituted of three key elements - the measure ment of the dimensions of class structure in Brazilian capitalism; the observation of material interests related to the constituents locations of such structure; the development of measures of association between the insertion in class groupings and indivi dual voting behavior. Based on the neo - Marxist approach of class analysis, especially as formulated by Wright, it is made an adaptation of the typology formulated by such approach (mainly developed by Santos to the Brazilian case) to the data available fro m databases of censuses of 2000 and 2010. This theoretical construct reveals that during the period considered for the analysis, the structure of class - relations in Brazil became more proletarized and consequently had a decrease of the dimensions of the de stitute class locations. In addition, it was found, in relation to the objective class interests, widespread increments of economic welfare that allowed advances in relation to the material conditions of the proletariat, without, however, incurring losses to the privileged class positions. Such changes in the structural sphere focused in various ways on the political arena. Based on an adaptation to electoral analysis of the concept of "class formation", also formulated by Wright, associated with the use of techniques of ecological inference (especially those proposed by King and associates), it was possible to draw up an overview of class voting in period studied. As main results, three general patterns of individual voting behavior, related to each of the three analyzed class groupings were identified - a contraposition against PT candidates, by voters in privileged class locations; the adhesion, recurring throughout the study period, of workers to Lula and Dilma Rousseff; a favorable electoral shift unde rtaken by economically deprived voters in favor of those candidatures in the 2006 election.