True random number generator implemented in 130 nm CMOS nanotechnology

Random generators systems have the capacity to generate cryptographic keys which, when mixed with the in formation, hide it in an efficient and timely manner. There are two categories of RNG, being truly random (TRNG) or pseudorandom (PRNG). To study the entropy source based on the noise of an oscillator, and to achieve that, an RNG circuit was designed to have a low power consumption, a high randomness and a low cost and area usage. The chosen architecture for this paper is a hybrid RNG, which uses oscillators and a chaotic circuit to generate the random bits. With the simulation of the circuit, it was found to be at the objectives mark, having a low power consumption of 1.19 mW, a high throughput of 25 Mbit/s and an energy per bit of 47.6 pJ/bit. However, due to limitations with the simulation, it wasn’t possible to run all the statistical tests, although all the ran tests were passed.info:eu-repo/semantics/publishedVersio

A domain-specific language for parallel and grid computing

This paper overviews a Domain-Specific Language (DSL) for parallel and grid computing, layered on top of AspectJ. This DSL aims to bridge the gap between sequential code and parallel/grid applications, by avoiding invasive source code changes in scientific applications. Moreover, it aims to promote the localization of parallelization and gridification issues into well defined modules that can be (un)plugged (from)to existing scientific applications. This paper builds on previous work based on AspectJ and presents the main motivations for implementing a DSL in preference to a pure-AspectJ solution. The paper presents the DSL's design rationale, overviews current implementation and open research issues.(undefined)info:eu-repo/semantics/publishedVersio

Ciclos políticos e ciclos eleitorais nas eleições legislativas portuguesas 1985-2009

Este trabalho segue atentamente as teorias oportunistas do modelo de ciclos político-económicos e a sua adequação às eleições para a Assembleia da Republica durante o período 1985-2009. Estas teorias foram testadas para as variáveis macroeconómicas, bem como ao nível de indicadores orçamentais de despesa pública em função dos atos eleitorais legislativos, tendo sido utilizado como base a série longa do Banco de Portugal (BdP): “Quarterly Series for the Portuguese Economy: 1977-2011”, bem como os resultados eleitorais disponibilizados pela Comissão Nacional de Eleições. Não se encontraram evidências de existência de políticas oportunistas no caso da inflação e do desemprego para a totalidade do período. Foram encontrados indícios de oportunismo pontual em variáveis da despesa pública, nomeadamente no Consumo Público e Transferências Internas, tendo sido dada maior relevância a atos eleitorais onde o incumbente se apresenta a votos tendo beneficiado de uma legislatura completa no Governo. A investigação concluiu que modelos centrados em variáveis orçamentais podem ser usados para aprofundar o impacto dos ciclos eleitorais nas políticas públicas. Estes modelos possuem alguma sustentação ao longo da serie apesar das restrições resultantes da instabilidade politica portuguesa e ciclos económicos complexos durante o período em analise.This work follows closely the theories opportunistic model of political-economic cycles and their suitability for election to the Assembly of the Republic during the period 1985-2009. These theories were tested studying the behavior of macroeconomic and fiscal indicators of public expenditure as the Legislative elections approached. The long series the Bank of Portugal (BoP): "Quarterly Series for the Portuguese Economy: 1977-2011 " and the election results provided by the National Elections Commission, where used as the initial dataset. There was no evidence of the existence of political opportunists in the case of inflation and unemployment for the entire period. Having found no evidence of the existence of political manipulation regarding inflation or unemployment for the entire period, we proceeded in adapting the model of opportunistic economical-political cycles to variables of public expenditure, particularly in quarterly annual rate of public consumption, and internal transfers where punctual evidence of opportunism in public spending, was detected Having focused our attention in those elections in which the Incumbent is running for office having served a full term in Government, the investigation concluded that models based on fiscal variables can be used to measure the impact of electoral cycles in public policy. These models have some support along the series despite the restrictions resulting from political instability and economic Portuguese cycles during the period under review

Roland Morris disability questionnaire adaptation and validation for the Portuguese speaking patients with back pain

O objectivo do presente estudo foi adaptar e validar para a língua portuguesa o Roland Morris Disability Questionnaire (RMDQ) por não existirem escalas em Português Euro- peu para avaliar o grau de incapacidade dos doentes com lombalgias. Após os procedi- mentos de tradução e retroversão, a versão portuguesa do RMDQ foi testada em 112 doentes com lombalgias (30 homens e 82 mulheres), a fim de analisar as suas característi- cas psicométricas. A análise da fidelidade das medidas indica que o RMDQ apresenta níveis elevados de consistência interna ( α de Cronbach: 0,81) e de estabilidade temporal (correlação teste-reteste: 0,86). A validade externa foi avaliada através da convergência com resultados obtidos através da Escala Numérica de Dor (END), do Teste de Schober (TS) e do grau de flexão anterior da coluna (GFA). Os resultados revelaram uma correlação elevada entre o RMDQ e o END (r = 0,73) e uma correlação moderada com o TS e o GFA (respectivamente, r = -0,52 e r = 0,42). A análise psicométrica mostrou, assim, que o RMDQ fornece medidas fiáveis e válidas de incapacidade para o doente com lombalgia, encontrando-se assim adaptado e validado para os doentes portugueses

Ciclos político económicos nos municípios portugueses: fatores explicativos e implicações de uma política orçamental oportunista (2003-2017)

A presente tese de doutoramento avalia a existência de ciclos político económicos (CPE) nos municípios portugueses. É investigada a trajetória das diferentes rubricas da despesa pública ao longo dos mandatos dos Presidentes de Câmara e de que forma a limitação de mandatos autárquicos afetou a política orçamental local. Para tal, foi criada uma base de dados original, especificamente desenhada para responder a este propósito de pesquisa. Os dados em que se suporta a análise reportam a 275 dos 278 municípios portugueses do continente, abarcando o lapso de tempo entre 2003 e 2017. Os testes empíricos realizados revelam a existência de comportamentos oportunistas por parte dos Presidentes de Câmara relativamente à despesa municipal, especialmente às despesas de capital. Os resultados indicam a ocorrência de ciclos oportunistas em rubricas de despesa mais visíveis para o eleitorado, um comportamento consistente com a sinalização de competência ao eleitorado por parte do incumbente. Esta conclusão é consistente com o observado em estudos anteriores sobre ciclos político económicos municipais. A introdução da limitação de mandatos no panorama autárquico veio reforçar a competitividade eleitoral e as contas públicas, pelo menos nos anos de maior rotatividade, reduzindo a observação de ciclos políticos económicos. Não foram identificados comportamentos oportunistas relativamente às rubricas de receita. Por fim, não foi identificado qualquer padrão ideológico na despesa pública, pelo que é possível concluir que a dicotomia esquerda/direita não aparenta ter influência na forma como são orçamentalmente geridos os municípios. Ao contrário das conclusões de estudos anteriores, ambos os lados do espectro ideológico são igualmente oportunistas.This doctoral thesis assesses the existence of political economic cycles (PBC) in Portuguese municipalities. The behaviour of the different items of public expenditure is inquired throughout the terms of Mayors. Similarly, it is appraised how the limitation of municipal mandates affected local budgetary policy. To this end, an original database was created, specifically designed to respond to this research purpose. The data set used in the empirical work is based on financial information for 275 (out of 278) Portuguese continental municipalities from 2003 to 2017. The study reveals the existence of opportunistic behaviour by Mayors seeking re-election regarding municipal expenditure, especially capital expenditure. The empirical results indicate the occurrence of opportunistic cycles in more visible items of expenditure for the electorate, a behaviour consistent with the incumbent's signalling of competence to the electorate. The introduction of limitation of mandates at the municipal level has strengthened electoral competitiveness and public accounts, at least in the electoral years in which the incumbent cannot run for office. Regarding revenues, no opportunistic behaviours were identified. Finally, no ideological pattern emerges regarding municipal public spending, so we can say that the left / right dichotomy does not appear to have any influence on how municipalities are managed. Unlike previous studies, we conclude that both ends of the political spectrum are shown to be equally opportunistic

A robust feature extraction for automatic speech recognition in noisy environments

This paper presents a method for extraction of speech robust features when the external noise is additive and has white noise characteristics. The process consists of a short time power normalisation which goal is to preserve as much as possible, the speech features against noise. The proposed normalisation will be optimal if the corrupted process has, as the noise process white noise characteristics. With optimal normalisation we can mean that the corrupting noise does not change at all the means of the observed vectors of the corrupted process. As most of the speech energy is contained in a relatively small frequency band being most of the band composed by noise or noise-like power, this normalisation process can still capture most of the noise distortions. For Signal to Noise Ratio greater than 5 dB the results show that for stationary white noise, the normalisation process where the noise characteristics are ignored at the test phase, outperforms the conventional Markov models composition where the noise is known. If the noise is known, a reasonable approximation of the inverted system can be easily obtained performing noise compensation still increasing the recogniser performance

Comparisons between synchronizing circuits to control algorithms for single-phase active converters

This paper presents a comparative analysis between synchronizing circuits applied to control algorithms for single-phase active converters. One of these synchronizing circuits corresponds to the single-phase PLL (Phase Locked Loop), implemented in α-β coordinates, whereas the other one corresponds to the E-PLL (Enhanced PLL). These synchronizing circuits are compared in several aspects as processing and settling time and memory space requirements. Moreover, the performance of a single-phase back-to-back converter is also presented, with its control algorithm based on these Synchronizing Circuits. Each one of the control algorithms were implemented in a DSP microprocessor TMS320F2812F from Texas Instruments. Simulation and experimental results, through a back-to-back converter prototype, are presented.Fundação para a Ciência e a Tecnologia (FCT

A Recommender System Based on Cohorts’ Similarity

[Abstract] Aiming to better understand the genetic and environmental associations of Alzheimer's disease, many clinical trials and scientific studies have been conducted. However, these studies are often based on a small number of participants. To address this limitation, there is an increasing demand of multi-cohorts studies, which can provide higher statistical power and clinical evidence. However, this data integration implies dealing with the diversity of cohorts structures and the wide variability of concepts. Moreover, discovering similar cohorts to extend a running study is typically a demanding task. In this paper, we present a recommendation system to allow finding similar cohorts based on profile interests. The method uses collaborative filtering mixed with context-based retrieval techniques to find relevant cohorts on scientific literature about Alzheimer's diseases. The method was validated in a set of 62 cohorts.National Science Foundation (Portugal); POCI-01-0145-FEDER-01638

Aspect oriented pluggable support for parallel computing

In this paper, we present an approach to develop parallel applications based on aspect oriented programming. We propose a collection of aspects to implement group communication mechanisms on parallel applications. In our approach, parallelisation code is developed by composing the collection into the application core functionality. The approach requires fewer changes to sequential applications to parallelise the core functionality than current alternatives and yields more modular code. The paper presents the collection and shows how the aspects can be used to develop efficient parallel applicationsFundação para a Ciência e a Tecnologia (FCT) - PPC-VM (Portable Parallel Computing based on Virtual Machines) Project POSI/CHS/47158/2002; SOFTAS (POSI/EIA/60189/2004).Fundo Europeu de Desenvolvimento Regional (FEDER)