Hybrid Pipeline Hardware Architecture Based on Error Detection and Correction for AES.

Currently, cryptographic algorithms are widely applied to communications systems to guarantee data security. For instance, in an emerging automotive environment where connectivity is a core part of autonomous and connected cars, it is essential to guarantee secure communications both inside and outside the vehicle. The AES algorithm has been widely applied to protect communications in onboard networks and outside the vehicle. Hardware implementations use techniques such as iterative, parallel, unrolled, and pipeline architectures. Nevertheless, the use of AES does not guarantee secure communication, because previous works have proved that implementations of secret key cryptosystems, such as AES, in hardware are sensitive to differential fault analysis. Moreover, it has been demonstrated that even a single fault during encryption or decryption could cause a large number of errors in encrypted or decrypted data. Although techniques such as iterative and parallel architectures have been explored for fault detection to protect AES encryption and decryption, it is necessary to explore other techniques such as pipelining. Furthermore, balancing a high throughput, reducing low power consumption, and using fewer hardware resources in the pipeline design are great challenges, and they are more difficult when considering fault detection and correction. In this research, we propose a novel hybrid pipeline hardware architecture focusing on error and fault detection for the AES cryptographic algorithm. The architecture is hybrid because it combines hardware and time redundancy through a pipeline structure, analyzing and balancing the critical path and distributing the processing elements within each stage. The main contribution is to present a pipeline structure for ciphering five times on the same data blocks, implementing a voting module to verify when an error occurs or when output has correct cipher data, optimizing the process, and using a decision tree to reduce the complexity of all combinations required for evaluating. The architecture is analyzed and implemented on several FPGA technologies, and it reports a throughput of 0.479 Gbps and an efficiency of 0.336 Mbps/LUT when a Virtex-7 is used.

Estimation of peach supply response in Colombia using a Vector Error Correction Model / Estimación de la respuesta de la oferta de durazno en Colombia mediante el modelo de vector de corrección de errores / Estimativa da resposta de fornecimento de pêssego na Colômbia usando um Modelo de Correcção de Erros Vectoriais

ABSTRACT An empirical study of peach supply response to own-price and yield in Colombia using time series data from 2000 to 2018 was undertaken. A quantitative, correlational and non-experimental research design was selected and the Johansen's co-integration as well as the vector error correction framework were employed. The Augmented Dickey-Fuller test showed that the time series were integrated of order one and the Johansen's co-integration confirmed the existence of a long-term relationship between the variables. Moreover; the short and long run coefficients for own-price and yield were statistically significant and presented the expected signs, however estimated own-price elasticity was below unit suggesting it is not an important factor in peach supply response. Furthermore, the vector error correction coefficient (-0.32) was negative and in line with theory which showed that in the long-run, the model converges towards equilibrium, however at a relatively slow pace. Therefore, it can be concluded that, overall, the proposed model contributes to the understanding of the dynamics in peach output supply

RESUMEN Se realizó un estudio empírico sobre la respuesta a la oferta de durazno con relación a su precio y rendimiento agr'cola en Colombia, utilizando datos de series de tiempo para el per'odo comprendido entre 2000 y 2018. Se seleccionó un diseño de investigación cuantitativo, correlacional y no experimental y se empleó la cointegración de Johansen y el modelo de vector de corrección de errores. Los resultados de la a prueba de Aumentada de Dickey-Fuller demostraron que las series temporales estaban integradas en el orden uno y la cointegración de Johansen confirmó la existencia de una relación a largo plazo entre las variables. Además, los coeficientes del precio y rendimiento a largo y corto plazo fueron estadísticamente significativos y presentaron los signos esperados. Sin embargo, la elasticidad precio estimada fue inferior a la unidad, lo cual sugiere que no es un factor importante en la respuesta de la oferta de durazno. Asimismo, el coeficiente de corrección de error del vector (-0.32) fue negativo y en línea con la teoría, denostando que, a largo plazo, el modelo converge hacia al equilibrio, pero a una velocidad relativamente lenta. Por lo tanto, se puede concluir que, en general, el modelo propuesto, contribuye a la comprensión de la dinámica de la respuesta de la oferta de durazno.

RESUMO Realizou-se um estudo empírico da resposta da oferta de pêssego em função do seu preço e rendimento agrícola na Colômbia, usando dados de séries temporais para o período entre 2000 a 2018. O estudo usou um desenho de pesquisa quantitativa, correlacional e não experimental assim como a cointegração de Johansen e o modelo Vetorial de Correção de Erro. Os resultados do teste Aumentado de Dickey-Fuller demonstraram que as séries são integradas de ordem um e a cointegração de Johansen confirmou a existência de uma relação de longo prazo entre as variáveis. Além disso, os coeficientes do curto e longo prazo para preço e rendimento foram estatisticamente significantes e apresentaram os sinais esperados; no entanto, a elasticidade estimada do preço foi menor que a unidade, sugerindo que não é um fator importante na resposta da oferta de pêssego. Além disso, o coeficiente de correção de erros vetoriais (-0,32) foi negativo e alinhado à teoria, que mostrou que, a longo prazo, o modelo converge para o equilíbrio, porém a um ritmo relativamente lento. Portanto, pode-se concluir que, de maneira geral, o modelo proposto contribui para entender a dinâmica da oferta de produção de pêssego.

Energy-Efficient Channel Coding Strategy for Underwater Acoustic Networks.

Underwater acoustic networks (UAN) allow for efficiently exploiting and monitoring the sub-aquatic environment. These networks are characterized by long propagation delays, error-prone channels and half-duplex communication. In this paper, we address the problem of energy-efficient communication through the use of optimized channel coding parameters. We consider a two-layer encoding scheme employing forward error correction (FEC) codes and fountain codes (FC) for UAN scenarios without feedback channels. We model and evaluate the energy consumption of different channel coding schemes for a K-distributed multipath channel. The parameters of the FEC encoding layer are optimized by selecting the optimal error correction capability and the code block size. The results show the best parameter choice as a function of the link distance and received signal-to-noise ratio.

Spectacle-wear compliance in school children in Concepción Chile.

PURPOSE: Although international policies promote programs for correction of refractive errors in school children, recent studies report low compliance with respect to spectacle wear. Our aim was to assess spectacle-wear compliance and identify associated visual factors among children participating in Chile's school spectacle provision program. METHODS: A total of 270 school children were prescribed spectacles and monitored after 1 year. Visual acuity, refractive error, reasons for not wearing spectacles, and self-reported visual function were assessed. Compliance is reported as the proportion of children wearing spectacles at the 1-year visit. Factors associated with compliance and reasons for not wearing spectacles were examined using contingency table analyses. Logistic models were constructed to assess independently associated factors. RESULTS: Only 204 children (76%) participated in the 1-year follow-up. Mean age was 10 years (range 4-19 years); 58% were girls, 42% boys. Overall compliance was 58%. Spectacle use was independently associated with age and refractive error. Older children were less likely to be compliant (odds ratio, OR, 0.8, 95% confidence interval, CI, 0.76-0.92/year of increasing age). Compared with children with refractions of -0.75 to +0.75 diopters, both myopic and hyperopic children were more compliant (OR 4.93, 95% CI 2.28-10.67 and OR 2.37, 95% CI 1.06-5.31, respectively). Primary reasons for not wearing spectacles included breakage/loss in younger children, and disliking the appearance in teenagers. CONCLUSION: We found greater compliance in spectacle wear than that reported in most published studies. Guidelines for provision of children's spectacles should consider excluding children with mild refractive error and improving spectacle quality and appearance.

Transmissão e a influência do volume dos estoques públicos sobre o preço do arroz no Brasil / Transmission and influence of volume of public stocks on the price of rice in Brazil

Este trabalho analisou o mecanismo de transmissão dos preços dos principais estados produtores de arroz no Brasil (Rio Grande do Sul, Mato Grosso e Santa Catarina), como variáveis endógenas, e volume dos estoques públicos no Brasil, como variável exógena, para o período de julho de 2004 até dezembro de 2010. A análise compreende o uso da metodologia VAR-VEC para identificar o número de defasagens utilizadas e verificar se existem co-integrações entre as variáveis, por meio do Teste de Co-integração de Johansen. Testou-se a existência de causalidade entre as séries pelo método de causalidade de Granger. Aplicou-se a decomposição da variância do erro de previsão e a função impulso-resposta com decomposição de Cholesky para analisar a relação entre os preços dos estados e volume em estoques públicos. Com a aplicação da metodologia proposta, pode-se observar que o preço do arroz no estado do Rio Grande do Sul influencia no preço no estado de Santa Catarina e no volume armazenado em estoques públicos e é influenciado pelo preço do arroz no estado do Mato Grosso.

This study examined the mechanism of prices from major rice producing states in Brazil (Rio Grande do Sul, Mato Grosso and Santa Catarina), as endogenous variables, and volume of public stocks in Brazil, as exogenous variables for the period July 2004 until December 2010. The analysis includes the use of VAR-VEC methodology to identify the number of lags used and check for co-integration among variables through the test of Johansen Co-integration. We tested the existence of causality between variables by the method of Granger causality. We applied the variance decomposition of forecast error and impulse-response function with Cholesky decomposition to analyze the relationship between prices and volume of the states in public stocks. With the proposed methodology, one can observe that the price of rice in the state of Rio Grande do Sul to the price in the state of Santa Catarina and the volume stored in stockpiles and is influenced by the price of rice in the state of Mato Grosso.

Transmissão e a influência do volume dos estoques públicos sobre o preço do arroz no Brasil

This study examined the mechanism of prices from major rice producing states in Brazil (Rio Grande do Sul, Mato Grosso and Santa Catarina), as endogenous variables, and volume of public stocks in Brazil, as exogenous variables for the period July 2004 until December 2010. The analysis includes the use of VAR-VEC methodology to identify the number of lags used and check for co-integration among variables through the test of Johansen Co-integration. We tested the existence of causality between variables by the method of Granger causality. We applied the variance decomposition of forecast error and impulse-response function with Cholesky decomposition to analyze the relationship between prices and volume of the states in public stocks. With the proposed methodology, one can observe that the price of rice in the state of Rio Grande do Sul to the price in the state of Santa Catarina and the volume stored in stockpiles and is influenced by the price of rice in the state of Mato Grosso.

Este trabalho analisou o mecanismo de transmissão dos preços dos principais estados produtores de arroz no Brasil (Rio Grande do Sul, Mato Grosso e Santa Catarina), como variáveis endógenas, e volume dos estoques públicos no Brasil, como variável exógena, para o período de julho de 2004 até dezembro de 2010. A análise compreende o uso da metodologia VAR-VEC para identificar o número de defasagens utilizadas e verificar se existem co-integrações entre as variáveis, por meio do Teste de Co-integração de Johansen. Testou-se a existência de causalidade entre as séries pelo método de causalidade de Granger. Aplicou-se a decomposição da variância do erro de previsão e a função impulso-resposta com decomposição de Cholesky para analisar a relação entre os preços dos estados e volume em estoques públicos. Com a aplicação da metodologia proposta, pode-se observar que o preço do arroz no estado do Rio Grande do Sul influencia no preço no estado de Santa Catarina e no volume armazenado em estoques públicos e é influenciado pelo preço do arroz no estado do Mato Grosso.

Transmissão e a influência do volume dos estoques públicos sobre o preço do arroz no Brasil

This study examined the mechanism of prices from major rice producing states in Brazil (Rio Grande do Sul, Mato Grosso and Santa Catarina), as endogenous variables, and volume of public stocks in Brazil, as exogenous variables for the period July 2004 until December 2010. The analysis includes the use of VAR-VEC methodology to identify the number of lags used and check for co-integration among variables through the test of Johansen Co-integration. We tested the existence of causality between variables by the method of Granger causality. We applied the variance decomposition of forecast error and impulse-response function with Cholesky decomposition to analyze the relationship between prices and volume of the states in public stocks. With the proposed methodology, one can observe that the price of rice in the state of Rio Grande do Sul to the price in the state of Santa Catarina and the volume stored in stockpiles and is influenced by the price of rice in the state of Mato Grosso.

Este trabalho analisou o mecanismo de transmissão dos preços dos principais estados produtores de arroz no Brasil (Rio Grande do Sul, Mato Grosso e Santa Catarina), como variáveis endógenas, e volume dos estoques públicos no Brasil, como variável exógena, para o período de julho de 2004 até dezembro de 2010. A análise compreende o uso da metodologia VAR-VEC para identificar o número de defasagens utilizadas e verificar se existem co-integrações entre as variáveis, por meio do Teste de Co-integração de Johansen. Testou-se a existência de causalidade entre as séries pelo método de causalidade de Granger. Aplicou-se a decomposição da variância do erro de previsão e a função impulso-resposta com decomposição de Cholesky para analisar a relação entre os preços dos estados e volume em estoques públicos. Com a aplicação da metodologia proposta, pode-se observar que o preço do arroz no estado do Rio Grande do Sul influencia no preço no estado de Santa Catarina e no volume armazenado em estoques públicos e é influenciado pelo preço do arroz no estado do Mato Grosso.