Radio Frequency IDentification (RFID) is a contactless, automatic identification wireless technology primarily used for identifying and tracking of objects, goods and humans. RFID is not only limited to identification and tracking applications. This proliferating wireless technology has been deployed in numerous securities sensitive applications e.g. access control, e-passports, contactless payments, driver license, transport ticking and health cards. RFID inherits all the security and privacy problems that are related to wireless technology and in addition to those that are specific to RFID systems. The security and privacy protection schemes proposed in literature for wireless devices are mostly secured through symmetric/asymmetric keys encryption/decryption and hash functions. The security of all these cryptographic algorithms depends on computationally complex problems that are hard to compute using available resources. However, these algorithms require cryptographic operations on RFID tags which contradict the low cost demand of RFID tags. Due to limited number of logic gates in tags, i.e., 5K-10K, these methods are not practical. Much research effort has done in attempt to solve consumer's privacy and security problem. Solutions that prevent clandestine inventory are mostly application layer techniques. To solve this problem, a new RFID physical layer scheme has been proposed namely Direct Sequence Backscatter Encryption (DSB Enc). The proposed scheme uses level generator to produce different levels before transmitting the signal to the tag. The tag response to the signal sent by the reader using backscatter communications on the same signal which looks random to the eavesdropper. Therefore eavesdropper cannot extract the information from reader to tag and tag to reader communication using passive eavesdropping. As reader knows the different generated levels added to the carrier signal, it can remove the levels and retrieve the tag's messages. We proposed a lightweight, low-cost and practically secure physical layer security to the RFID system, for a supply chain processing application, without increasing the computational power and tag's cost. The proposed scheme was validated by simulations on GNU Radio and experimentation using SDR and a WISP tag. Our implementation and experimental results validate that DSB Enc is secure against passive eavesdropping, replay and relay attacks. It provides better results in the presence of AWGN channel.

Made available in DSpace on 2015-04-14T13:35:29Z (GMT). No. of bitstreams: 1 438183.pdf: 1878896 bytes, checksum: 1f08bfc6e7ffe54e3816aea2d06e7d3a (MD5) Previous issue date: 2012-03-19 / Introduction: Aging is a life cycle stage that may be associated with higher or lower limits imposed by the years. Among these limitations we find the presence of different degrees of cognitive impairment, particularly memory, affecting the daily activities and may interfere with the functioning of the individual. Despite the knowledge that the aging indicate a positive association between serum levels of brain-derived neurotrophic factor (BDNF), hippocampal volume and cognitive functions, very few studies explore these aspects together. However the association between these three aspects and their relationship to changes in activities of daily living was not found in the literature reviewed. Objectives: To investigate the relationship between serum levels of BDNF, hippocampal volumes, memory performance and functionality in a sample of elderly. Subjects and Methods: Forty-nine subjects of both sexes, right handed, aged from 60 years were selected from examinations of hippocampal volumetry (Magnetom Vision Plus 1.5 T) requested by the neurologist from complaints of forgetfulness. To the exclusion criteria was applied a short scale in Portuguese-validated Structured Clinical Interview, SCID-IV-TR (Structured Clinial Interview For DSM-IV-TR) that allows the diagnosis of major mental disorders (mood episodes, psychosis, abuse substances, anxiety and somatoform disorders). It was also an exclusion criterion: deafness, blindness and mental retardation. To assess cognitive deficits was administered the mini mental state examination (MMSE). In the evaluation of verbal memory (logical memory) and visual (visual reproduction), early and late was applied to the Wechsler Memory Scale (WMS-R), and the Verbal Learning Test of Rey assessing learning immediate recall and recognition later. For the functional assessment of activities of daily living scales were applied functional Katz and Lawton. After application of these tests were submitted to the elderly collection, fasting, 5 ml of blood by venipuncture and forwarded it to the laboratory of immunology at the industry-HSL PUCRS to be subsequently carried out the analysis of BDNF serum using sandwich Kit - ELISA. Thus, this study examined the relationship between the levels of BDNF with the results of hippocampal volumetry and memory performance and functionality that this sample of elderly. Results: Considering the comparison between BDNF and volume of the hippocampus was detected statistically significant positive correlation, indicating that the lower serum levels of BDNF was related with shrinkage of the hippocampus, both on the right (r = 0.407, p <0.001) and the left (r = 0.593, p <0.001). When BDNF was compared to MMEE, there was also a significant correlation (r = 0.493, p <0.001). In the analysis between BDNF and tests related to memory, all associations were significant and positive, indicating that poor performance on memory tests Rey Verbal, and WMS-R (ML) I was significantly correlated to lower values of serum levels of BDNF, respectively, (r=0,555; p<0,001) and (r=0,589; p<0,001). A similar correlation was observed comparisons between BDNF and Lawton (r = 0.511, p <0.001). Considering the comparison between volumetry of the hippocampus and tests related to memory, there was a significant positive association in virtually all tests assessed, namely, REY Verbal (r = 0.555, p <0.001) REY VERBAL R (r = 0.531, p <0.001), functional scale (r = 0.374, p 0, 008) and MMEE (r = 0.358, p 0.012). A volumetric reduction of the hippocampus was associated with decrease of memory. Conclusion: Our findings suggest a possible association between reductions in BDNF serum levels, shrinkage of the hippocampus, episodic memory deficits, and dysfunction in activities of daily living. It should be noted, therefore, the potential diagnostic power of BDNF, when associated with hippocampal volumetric MRI, memory test and evaluation functional. They will become reliable biomarkers of neurodegenerative diseases associated with aging, especially in its early stages, as a rule, there are only changes in memory. / Introdu??o: O envelhecimento ? uma fase do ciclo vital que pode cursar com maior ou menor limita??o imposta pelo decorrer dos anos. Dentre estas limita??es podemos encontrar a presen?a de diferentes graus de decl?nio cognitivo, particularmente da mem?ria, comprometendo as atividades de vida di?ria e interferindo na funcionalidade do indiv?duo. Estudos do envelhecimento indicam uma associa??o entre os n?veis s?ricos do fator neurotr?fico derivado do c?rebro (BDNF), volume hipocampal e fun??es cognitivas. No entanto a associa??o entre esses tr?s aspectos e suas correspond?ncias nas modifica??es das atividades de vida di?ria, n?o foi encontrada na literatura revisada. No entanto a associa??o entre esses tr?s aspectos e suas correspond?ncias nas modifica??es das atividades de vida di?ria, n?o foi encontrada na literatura revisada. Objetivos: Verificar a rela??o entre os n?veis s?ricos do BDNF e os volumes hipocampais, o desempenho de mem?ria e a funcionalidade em uma amostra de idosos. Sujeitos e M?todos: Quarenta e nove sujeitos de ambos os sexos, destros, com idade a partir de 60 anos foram selecionados a partir dos exames de volumetria hipocampal (Magnetom Vision Plus de 1,5 T) solicitados pelo neurologista a partir de queixas de esquecimentos. Para os crit?rios de exclus?o foi aplicada uma escala breve validada em portugu?s Entrevista Cl?nica Estruturada, SCID- IV-TR (Structured Clinial Interview For DSM-IV-TR) que permite o diagn?stico dos principais transtornos mentais (epis?dios de humor, psicose, abuso de subst?ncias, transtorno de ansiedade e somatoformes). Tamb?m foi crit?rio de exclus?o: surdez, cegueira e retardo mental. Para avaliar os d?ficits cognitivos foi aplicado o mini exame do estado mental (MMEE). Na avalia??o da mem?ria verbal (mem?ria l?gica) e visual (reprodu??o visual), imediata e tardia foi aplicada a Escala de Mem?ria de Wechsler (WMS-R), al?m do teste do Aprendizado Verbal de Rey que avalia aprendizado de mem?ria imediata e de reconhecimento tardio. Para a avalia??o funcional das atividades da vida di?ria foram aplicadas as escalas funcionais de Katz e de Lawton. Ap?s a aplica??o destes testes os idosos foram submetidos ? coleta, em jejum, de 5 ml de sangue por venopun??o e este encaminhado ao laborat?rio do setor de imunologia do HSL-PUCRS para, posteriormente, ser realizada a an?lise do BNDF s?rico utilizando o Kit sandwich ELISA. Desta maneira, este estudo analisou a rela??o dos n?veis de BDNF com os resultados da volumetria hipocampal e o desempenho da mem?ria e da funcionalidade nesta referida amostra de idosos. Resultados: Considerando a compara??o entre BDNF e volumetria do hipocampo, foi detectada correla??o estat?stica significativa e positiva (p<0,001), indicando que, quanto menor os n?veis s?ricos do BDNF menor o volume do hipocampo, tanto o direito (r=0,407; p<0,001) quanto o esquerdo (r=0,593; p<0,001). Quando o BDNF foi comparado ao MMEE, a correla??o positiva e significativa tamb?m ocorreu (r=0,493; p<0,001). Nas an?lises das associa??es entre o BDNF e os testes referentes ? mem?ria, todas estas se mostraram significativas e positivas, indicando que um pior desempenho nos testes de mem?ria do REY Verbal R (evoca??o tardia) e na mem?ria verbal (evoca??o imediata), se correlacionaram a valores menores dos n?veis s?ricos do BDNF, respectivamente (r=0,555; p<0,001) e (r=0,589; p<0,001). Correla??o semelhante foi evidenciada nas compara??es entre BDNF e Lawton (r=0,511; p<0,001). Considerando a compara??o entre volumetria do hipocampo e os testes referentes ? mem?ria, houve associa??o positiva significativa em praticamente todas as rela??es avaliadas, REY VERBAL (r=0,555; p<0,001), e REY VERBAL R (r=0,531; p<0,001), na escala funcional (r=0,374; p=0,008) e MMEE (r=0,358; p=0,012) menor a volumetria do hipocampo. Conclus?o: Nossos resultados mostram que as redu??es observadas nos n?veis de BDNF s?ricos se associam com a diminui??o do volume do hipocampo, com d?ficits da mem?ria epis?dica e disfun??es nas atividades da vida di?ria. Destaca-se, portanto, o potencial do BDNF, quando associado ? volumetria hipocampal por RM, e aos testes de mem?ria e de avalia??o funcional, como marcadores importantes na identifica??o precoce de d?ficits cognitivos-funcionais, frequentemente presentes nas doen?as neurodegenerativas relacionadas ao processo de envelhecimento.

Made available in DSpace on 2015-04-14T13:35:55Z (GMT). No. of bitstreams: 1 458575.pdf: 2405331 bytes, checksum: 33fd1d0ad3d3f11fcf5b9cd9b9bff218 (MD5) Previous issue date: 2014-02-27 / Introduction: Psychiatric disorders are among the most common diseases and represent an important public health problem. The neurobiological processes implicated in the pathophysiology of neuropsychiatric disorders are not fully known. Exposure to adverse events in early life increases the risk of developing neuropsychiatric conditions in adulthood, including affective disorders and psychosis. In rodents, maternal separation (MS) is commonly used as a model of exposure to stress in early life. MS may cause long-term effects on brain function, including cellular, neurochemical and behavioral changes. The involvement of pro -inflammatory cytokines in neuropsychiatric disorders has attracted increasing interest from researchers. Topiramate is an antiepileptic drug that has proven to exhibit neuroprotective properties in animal models of brain injury, reducing neuronal damage in animal models of neonatal hypoxic ischemia and attenuating memory deficits. Objectives: To investigate the effect of Topiramate (Top) in reversing cognitive impairment in rats submitted to neonatal stress induced by MS and compare with Valproic Acid (Val), which was previously studied by our research group. Furthermore, to investigate the effects of neonatal stress with and without treatment with Val and Top on BDNF, TNF- &#945;, and Interleukin 10 (IL-10) levels. Methodology: Study on animal model of stress exposure in neonatal period (method of MS), in male rats. Treatment with Top and Val in adulthood: one group received 10mg/kg of Top orally once a day for 14 days, the other group received 100mg/kg of Top in the same period, another group received Val 200mg/kg orally in the same period, and the other group received the same corresponding amount in milliliters also orally of saline solution (control group). Behavioral tests (motor/exploratory activity, recognition memory), and analyzes of BDNF, TNF- &#945; , and IL-10 levels were performed in adulthood. Results: The MS during the neonatal period causes memory impairment in adult rats. The treatment in adults with Top caused injury to memory when used, independently of maternal separation. Likewise, it also failed to reverse the damage caused by MS. Pharmacological treatment with Val in adulthood reversed long-term (LTM) memory deficits induced by MS and caused an improvement in short-term memory (STM) in rats separated from the mother. The MS induced a significant increase in IL -10 when the separated-saline (MS - Sal) was compared with the control group (non-separated-saline, NS-Sal). Statistical comparisons of TNF-&#945; levels, indicated that the group subjected to MS which received saline (MS - Sal) showed a significant increase in the levels of TNF-&#945; in the hippocampus when compared with the control group. Similarly, the levels of TNF-&#945; in the group MS-Sal were also increased in cortex, compared to NS-Sal group. The MS induced a significant decrease in BDNF levels in the hippocampus, when the group MS-Sal was compared with the control group. No statistically significant difference was observed in the comparison of BDNF in prefrontal cortex. Conclusions: MS leads to persistent memory deficits and increases levels of the anti-inflammatory cytokine, IL-10, and of the pro-inflammatory cytokine, TNF-&#945;, and decreases levels of BDNF in adulthood. Val partially alleviated these memory deficits, while Top was ineffective. Surprisingly, the two drugs were able to recover levels of cytokines in brain regions studied. / Introdu??o: Os transtornos psiqui?tricos est?o entre as doen?as mais comuns e representam um importante problema de sa?de p?blica. Os processos neurobiol?gicos implicados na fisiopatologia dos transtornos neuropsiqui?tricos ainda n?o s?o totalmente conhecidos. A exposi??o a eventos adversos no in?cio da vida aumenta o risco de desenvolvimento de condi??es neuropsiqui?tricas na idade adulta, incluindo transtornos afetivos e psicose. Em roedores, a separa??o materna (SM) tem sido correntemente utilizada como um modelo de exposi??o ao estresse no in?cio da vida. A SM poder causar efeitos ? longo prazo na fun??o cerebral, incluindo altera??es celulares, neuroqu?micas e comportamentais. O envolvimento das citocinas pr? e antiinflamat?rias nas doen?as psiqui?tricas tem despertado cada vez mais o interesse dos pesquisadores. O topiramato ? um medicamento anti-epil?ptico que provou apresentar propriedades neuroprotetoras em modelos animais de les?o cerebral, reduzindo o dano neuronal em modelos animais de isquemia hip?xica neonatal e atenuando os d?ficits da mem?ria. Objetivos: Investigar o efeito do Topiramato (Top) na preven??o do preju?zo cognitivo em ratos Wistar submetidos a estresse neonatal, induzido pela SM e comparar com o ?cido Valpr?ico (Val). Investigar o efeito do estresse neonatal com e sem o tratamento com Top e Val sobre os n?veis de BDNF, TNF- &#945; e Interleucina 10 (IL-10). Metodologia: Estudo com modelo animal de exposi??o a estresse no per?odo neonatal (m?todo SM), em ratos machos. Tratamento com Top e Val na idade adulta: um grupo recebeu 10mg/Kg via oral de Top uma vez ao dia por 14 dias, o outro grupo recebeu 100mg/kg de Top no mesmo per?odo, outro grupo recebeu 200mg/kg via oral de Val no mesmo per?odo, e o outro grupo recebeu a mesma quantidade correspondente em mililitros tamb?m por via oral de solu??o salina (grupo controle). Testes comportamentais (atividade motora/explorat?ria, mem?ria), an?lises de BDNF, TNF &#945;, IL10 foram realizados na idade adulta. Resultados: A SM durante o per?odo neonatal causa preju?zo de mem?ria em ratos adultos. O tratamento na idade adulta com Top ocasionou preju?zo ? mem?ria quando utilizado independente da SM. Assim como, tamb?m n?o conseguiu reverter os danos ocasionados pela SM. O tratamento farmacol?gico com Valproato (Val) na vida adulta reverteu os d?ficits de mem?ria de longa- dura??o (LTM) induzidos pela priva??o materna e provocou uma melhora na mem?ria de curta-dura??o (STM) nos ratos separados da m?e. A SM induziu um aumento significativo nos n?veis de IL-10 quando o grupo separado-salina (S Sal) foi comparado com o grupo controle n?o separado-salina (NS-Sal). As compara??es estat?sticas dos n?veis de TNF-&#945;, indicaram que o grupo submetido ? SM que recebeu solu??o salina (S-Sal) apresentou um aumento significativo nos n?veis de TNF-&#945; no hipocampo quando comparado com o grupo de controle. Do mesmo modo, os n?veis de TNF-&#945; de animais do grupo S -Sal foram tamb?m aumentados no c?rtex, quando comparado com o grupo de NS Sal. A SM induziu um decr?scimo significativo nos n?veis de BDNF no hipocampo, quando o grupo S-Sal foi comparado com o grupo controle. Nenhuma diferen?a estatisticamente significativa foi observada na compara??o do BDNF no c?rtex pr?-frontal. Conclus?es: A SM induz a d?ficits de mem?ria persistentes e aumenta os n?veis da citocina anti-inflamat?ria, a IL-10, e da citocina pr? - inflamat?ria, o TNF-&#945;, e diminui os n?veis de BDNF na idade adulta. O Val parcialmente amenizou esses d?ficits de mem?ria, enquanto que o Top foi ineficaz. Surpreendentemente, as duas drogas foram capazes de recuperar os n?veis das citocinas nas regi?es cerebrais estudadas.

This thesis solves the impact of conventional compensation to the volumetric accuracy of the CNC machine. It is therefore a practical research work, where are in the theoretical introduction mentioned requirements for machine tools, the types of errors that can occur on three-axis kinematics, compensation for the control system Siemens Sinumerik 840D sl and devices by means of which are these compensation under the work formed and subsequently verified. In this work can be seen the measured values and graphs from each measurements, a detailed analysis of the results and drawing conclusions from these results.