Montgomery Modular Multiplication on Reconfigurable Hardware: Systolic versus Multiplexed Implementation

This paper describes a comparison of two Montgomery modular multiplication architectures: a systolic and a multiplexed. Both implementations target FPGA devices. The modular multiplication is employed in modular exponentiation processes, which are the most important operations of some public-key cryptographic algorithms, including the most popular of them, the RSA. The proposed systolic architecture presents a high-radix implementation with a one-dimensional array of Processing Elements. The multiplexed implementation is a new alternative and is composed of multiplier blocks in parallel with the new simplified Processing Elements, and it provides a pipelined operation mode. We compare the time × area efficiency for both architectures as well as an RSA application. The systolic implementation can run the 1024 bits RSA decryption process in just 3.23 ms, and the multiplexed architecture executes the same operation in 4.36 ms, but the second approach saves up to 28% of logical resources. These results are competitive with the state-of-the-art performance

ZipfTool: Uma ferramenta bibliométrica para auxílio na pesquisa teórica

Devido ao volume de trabalhos publicados nos veículos de divulgação científica, ferramentas de análise de dados textuais tornam-se importantes para diversas áreas de conhecimento. Utilitários dessa natureza oferecem ao usuário funcionalidadestanto em âmbito quantitativo quanto qualitativo. Do ponto de vista quantitativo, possibilitam identificar a frequência de ocorrência de palavras no texto e diferenciar verbos, substantivos e artigos definidos. Já as análises qualitativas tratam do levantamentode palavras de maior conteúdo semântico, da identificação de descritores e palavras chave no texto e do correlacionamento entre os termos de maior teor semântico.Este trabalho tem por finalidade apresentar o desenvolvimento de uma ferramenta de análise de dados que não somente possui primitivas de análise quantitativas mas também qualitativas. Quantitativamente a ferramenta fornece a frequência dos principaistermos do texto, enquanto qualitativamente ela identifica as palavras de maior teor semântico. Utilizando de técnicas advindas da bibliometria, a ferramenta apresentada, chamada de ZipfTool implementa tanto a 1a quanto a 2a Leis de Zipf. O estudode caso na área de arquitetura de computadores mostra uma redução do universo de artigos a serem analisados de 46785 para 1508 juntamente com técnicas bibliométricas.Permite também uma forma rápida e consistente dos principais descritores de um campo do conhecimento sob análise, contribuindo para qualificar sua compreensão

Comportamento Estratégico: Estudo de Caso em uma Organização do Setor Sucroenergético Brasileiro

The purpose of this paper is to understand the strategic behavior of an organization from the Brazilian ethanol industry. Specifically, this paper aimed to describe how the organization’s entrance in the Brazilian ethanol industry occurred, and to identify the organization’s positioning and strategic behavior through the application of Miles and Snow (1978) typology. Using a qualitative research design, a case study was conducted, based on documental research and semistructured interviews with three directors from the studied organization. We also utilized a structured questionnaire elaborated by Conant et al. (1990) and adapted by Gardelin (2010), aiming to categorize the strategies adopted by the organization. The results showed that the organization has a hybrid behavior pattern, varying from investigative to analytical, characterizing its strategic behavior through a dual strategy: on one hand, the organization investigates the environment and its competitive industry, introducing an innovative perspective in its external and internal operations; and on the other hand, the organization analyzes these internal and external contexts seeking a more effective positioning in national and international markets. Thus, Miles and Snow typology presents itself as an important research tool for the analysis and adoption of certain strategic positioning and decision making, establishing itself as a frame of reference for studies that seek to understand the strategic organizational reality.O objetivo do presente trabalho consistiu em compreender o comportamento estratégico de uma organização do setor sucroenergético brasileiro. Especificamente, buscou-se descrever como ocorreu o processo de entrada da organização no setor sucroenergético brasileiro e categorizar o comportamento e o posicionamento estratégico da organização a partir da aplicação da tipologia de Miles e Snow (1978). A partir de uma pesquisa qualitativa, efetuou-se um estudo de caso por meio de pesquisa documental e de entrevistas semiestruturadas junto a três diretores de uma das unidades da organização estudada. Também foi utilizado um questionário fechado, elaborado por Conant et al. (1990) e adaptado por Gardelin (2010), com o objetivo de categorizar as estratégias utilizadas pela organização. Os resultados indicaram que a organização estudada possui um padrão de comportamento híbrido, variando entre prospector e analítico, caracterizando o posicionamento da empresa a partir de uma dupla estratégia: ora prospectando o ambiente e o setor competitivo, introduzindo uma perspectiva inovadora em sua atuação interna e externa; ora analisando estes contextos internos e externos na busca de uma inserção no mercado local e internacional mais efetiva. Logo, a tipologia de Miles e Snow apresenta-se como importante instrumento de pesquisa para a análise e adoção de determinados posicionamentos estratégicos e para a tomada de decisão, mostrando-se assim como quadro de referência para a realização de estudos que procurem compreender a realidade estratégica organizacional. DOI:10.5585/riae.v13i1.203

Distribution extension of Amphisbaena lumbricalis Vanzolini, 1996 with its first predation record by snake Erythrolamprus viridis (Günther, 1862)

We expand the geographical distribution of Amphisbaena lumbricalis throughout the first record for a semiarid Caatinga area in the Paraíba state, northeastern Brazil. Furthermore, we report the first predation report of A. lumbricalis by the snake Erythrolamprus viridis. Our findings contribute with information about the habitats occupied by a hitherto considered “Data Deficient” species, beyond to reveal the potential of E. viridis to prey upon reptiles.Asociación Herpetológica Argentin

Thin and Deep Gaussian Processes

Gaussian processes (GPs) can provide a principled approach to uncertainty quantification with easy-to-interpret kernel hyperparameters, such as the lengthscale, which controls the correlation distance of function values. However, selecting an appropriate kernel can be challenging. Deep GPs avoid manual kernel engineering by successively parameterizing kernels with GP layers, allowing them to learn low-dimensional embeddings of the inputs that explain the output data. Following the architecture of deep neural networks, the most common deep GPs warp the input space layer-by-layer but lose all the interpretability of shallow GPs. An alternative construction is to successively parameterize the lengthscale of a kernel, improving the interpretability but ultimately giving away the notion of learning lower-dimensional embeddings. Unfortunately, both methods are susceptible to particular pathologies which may hinder fitting and limit their interpretability. This work proposes a novel synthesis of both previous approaches: Thin and Deep GP (TDGP). Each TDGP layer defines locally linear transformations of the original input data maintaining the concept of latent embeddings while also retaining the interpretation of lengthscales of a kernel. Moreover, unlike the prior solutions, TDGP induces non-pathological manifolds that admit learning lower-dimensional representations. We show with theoretical and experimental results that i) TDGP is, unlike previous models, tailored to specifically discover lower-dimensional manifolds in the input data, ii) TDGP behaves well when increasing the number of layers, and iii) TDGP performs well in standard benchmark datasets.Comment: Accepted at the Conference on Neural Information Processing Systems (NeurIPS) 202

Estrutura de uma Taxocenose de Anuros no Nordeste do Brasil

Based on data on diet and microhabitat use, we investigated the importance of current (ecological) and historical factors (phylogenetic) in the organization of an anuran assemblage in temporary ponds in a Caatinga area in Northeastern Brazil. The objective of this study was to verify how diet and microhabitat use influence the community structure, and their determinants. Niche breadth based on microhabitat use was relatively low for all species; thus, we also observed a spatial segregation between Hylidae and other families. The closely related species exhibit a more similar diet; the main prey categories used by Caatinga anurans were Coleoptera, insect larvae and Formicidae. The pseudo-community analysis based on diet and microhabitat use revealed that the observed niche overlap did not differ statistically from random, indicating a lack of detectable competition for these resources. The Canonical Phylogenetic Ordination (CPO) analyses revealed no significant phylogenetic effect on the assemblage, neither for diet nor for microhabitat use. Results suggest that predation and hydroperiod may be the most important factors in determining assemblage patterns, but more studies are needed to support this hypothesis.Keywords: community, Amphibia, ecological factors, historical factors.Com base em dados da dieta e uso de microhabitat, investigamos os fatores atuais (ecológicos) e históricos (filogenéticos) na organização de uma taxocenose de anuros de poças temporárias em uma área de Caatinga no Brasil. O objetivo desse estudo consistiu em verificar como a dieta e o uso de microhabitat influenciam a estrutura da comunidade, assim como suas determinantes. A amplitude de nicho no uso de microhabitat foi relativamente baixa para todas as espécies. Todavia, observou-se uma segregação espacial entre a família Hylidae e as demais. As principais categorias alimentares foram Coleoptera, larvas de Insecta e Formicidae. Espécies filogeneticamente próximas apresentaram dieta similar. A análise de pseudocomunidades revelou que as diferenças para os valores de dieta e uso de microhabitat não são significativas, indicando ausência de competição por esses recursos. A análise de ordenação canônica não detectou efeito significativo da filogenia para dieta e uso de microhabitat. Os resultados sugerem que o hidroperíodo e a predação podem ser os fatores mais importantes na determinação dos padrões da taxocenose, porém, mais estudos são necessários para sustentar essa hipótese.Palavras-chave: comunidade, Amphibia, fatores ecológicos, fatores históricos

Drug abusers have impaired cerebral oxygenation and cognition during exercise

Sem informaçãoBackground: Individuals with Substance Use Disorder (SUD) have lower baseline metabolic activity of the prefrontal cortex (PFC) associated with impairment of cognitive functions in decisionmaking and inhibitory control. Aerobic exercise has shown to improve PFC function and cognitive performance, however, its effects on SUD individuals remain unclear. Purpose: To verify the cognitive performance and oxygenation of the PFC during an incremental exercise in SUD individuals. Methods: Fourteen individuals under SUD treatment performed a maximum graded exercise test on a cycle ergometer with continuous measurements of oxygen consumption, PFC oxygenation, and inhibitory control (Stroop test) every two minutes of exercise at different intensities. Fifteen non-SUD individuals performed the same protocol and were used as control group. Results: Exercise increased oxyhemoglobin (O(2)Hb) and total hemoglobin (tHb) by 9% and 7%, respectively. However, when compared to a non-SUD group, this increase was lower at high intensities (p< 0.001), and the inhibitory cognitive control was lower at rest and during exercise (p< 0.007). In addition, PFC hemodynamics during exercise was inversely correlated with inhibitory cognitive performance (reaction time) (r = -0.62, p = 0.001), and a lower craving perception for the specific abused substance (p = 0.0189) was reported immediately after exercise. Conclusion: Despite SUD individuals having their PFC cerebral oxygenation increased during exercise, they presented lower cognition and oxygenation when compared to controls, especially at elevated intensities. These results may reinforce the role of exercise as an adjuvant treatment to improve PFC function and cognitive control in individuals with SUD.1211115Sem informaçãoSem informaçãoSem informaçã