Arm TrustZone: evaluating the diversity of the memory subsystem

Dissertação de mestrado em Engenharia Eletrónica Industrial e ComputadoresThe diversification of the embedded market has led the once single-purpose built embedded device to become a broader concept that can accommodate more general-purpose solutions, by widening its hardware and software resources. A huge diversity in system resources and requirements has boosted the investigation around virtualization technology, which is becoming prevalent in the embedded systems domain, allowing timing and spatial sharing of hardware and software resources between specialized subsystems. As strict timing demands imposed in realtime virtualized systems must be met, coupled with a small margin for the penalties incurred by conventional software-based virtualization, resort to hardware-assisted solutions has become indispensable. Although not a virtualization but security-oriented technology, Arm TrustZone is seen by many as a reliable hardware-based virtualization alternative, with the low cost and high spread of TrustZone-enabled processors standing as strong arguments for its acceptance. But, since Trust- Zone only dictates the hardware infrastructure foundations, providing SoC designers with a range of components that can fulfil specific functions, several key-components and subsystems of this technology are implementation defined. This approach may hinder a system designer’s work, as it may impair and make the portability of system software a lot more complicated. As such, this thesis proposes to examine how different manufacturers choose to work with the TrustZone architecture, and how the changes introduced by this technology may affect the security and performance of TrustZone-assisted virtualization solutions, in order to scale back those major constraints. It identifies the main properties that impact the creation and execution of system software and points into what may be the most beneficial approaches for developing and using TrustZone-assisted hardware and software.A recente metamorfose na área dos sistemas embebidos transformou estes dispositivos, outrora concebidos com um único e simples propósito, num aglomerado de subsistemas prontos para integrar soluções mais flexíveis. Este aumento de recursos e de requisitos dos sistemas potenciou a investigação em soluções de virtualização dos mesmos, permitindo uma partilha simultânea de recursos de hardware e software entre os vários subsistemas. A proliferação destas soluções neste domínio, onde os tempos de execução têm de ser respeitados e a segurança é um ponto-chave, tem levado à adoção de técnicas de virtualização assistidas por hardware. Uma tecnologia que tem vindo a ser utilizada para este fim é a Arm TrustZone, apesar de inicialmente ter sido desenvolvida como uma tecnologia de proteção, dado a sua maior presença em placas de médio e baixo custo quando comparada a outras tecnologias. Infelizmente, dado que a TrustZone apenas fornece diretrizes base sobre as quais os fabricantes podem contruir os seus sistemas, as especificações da tecnologia divergem de fabricante para fabricante, ou até entre produtos com a mesma origem. Aliada à geral escassez de informação sobre esta tecnologia, esta característica pode trazer problemas para a criação e portabilidade de software de sistema dependente desta tecnologia. Como tal, a presente tese propõe examinar, de uma forma sistematizada, de que forma diferentes fabricantes escolhem implementar sistemas baseados na arquitetura TrustZone e em que medida as mudanças introduzidas por esta tecnologia podem afetar a segurança e desempenho de soluções de virtualização baseadas na mesma. São identificadas as principais características que podem influenciar a criação e execução de software de sistema e potenciais medidas para diminuir o seu impacto, assim como boas práticas a seguir no desenvolvimento na utilização de software e hardware baseados na TrustZone

REDUCTION OF NITRIC OXIDE WITH CARBONACEOUS MATERIALS FROM PEAT

The direct NO reduction to produce N2 and CO2 using carbonaceous materials, chars and activated carbons, was studied. Chars were prepared from peat by pyrolysis, at temperatures ranging from 873 K to 1073 K. Activated carbons were prepared by the physical activation of chars with steam, in a steel reactor, at 1073 K for 12 minutes, 25 minutes and 45 minutes. The kinetics of NO reduction using chars and activated carbons produced at different experimental conditions were evaluated at different temperatures in the range 623-723 K. The gaseous products were essentially CO2 and N2 and the amount of CO produced was negligible. The effect of the temperature on the kinetics of reduction was also evaluated and the relationship between the rate constant and the temperature showed an Arrhenius dependence. Activation energies of the NO reduction were in the range 6.75 to 7.97 kcal.mol-1 for the chars and in the range 8.14 to 9.52 kcal.mol-1 for the activated carbons

Durability of bond in NSM CFRP-concrete systems under different environmental conditions

This paper addresses the durability of bond between concrete and carbon fibre reinforced polymer (CFRP) strips installed according to the near-surface mounted (NSM) technique (NSM CFRP-concrete systems) under the effects of two main groups of environmental conditions: (i) laboratory-based ageing conditions; (ii) real outdoor ageing conditions. The bond degradation was evaluated by carrying out direct pullout tests on aged specimens that were previously subjected to distinct environmental conditions for different periods of exposure. Moreover, the degradation of the mechanical properties of the involved materials was investigated. The digital image correlation (DIC) method was used to document the evolution of the deformation fields at the surface over the whole region of interest consisting of concrete and epoxy adhesive at the ligament region. This information supported the discussion about the evolution of the bond resistant mechanism developed in NSM CFRP-concrete specimens during testing, as well as the assessment of the bond quality of the system. In general, the results obtained from the durability tests conducted have shown that the different exposure environments, which may be considered as quite severe, did not result in significant damage on NSM CFRP-concrete system. The maximum decrease of about 12% on bond strength was obtained for real outdoor environments. Conversely, a maximum increase of 8% on bond strength was obtained on the specimens exposed to the temperature cycles between –15 °C and +60 °C. DIC allowed to document the stress transfer mechanisms established between the CFRP and the concrete substrate, revealing the crack patterns and the influence widths of the CFRP reinforcement strips, which were shown to be important for avoiding group effect when using multiple parallel strengthening CFRP strips.FEDER funds through the Operational Program for Competitiveness Factors - COMPETE and National Funds through FCT - Portuguese Foundation for Science and Technology under the projects CutInDur FCOMP-01-0124-FEDER-014811 (PTDC/ECM/112396/2009), FRPLongDur POCI-01-0145-FEDER-016900 (PTDC/ECM-EST/1282/2014) and partly financed by the project POCI-01-0145-FEDER-007633. The authors also like to thank all the companies that have been involved supporting and contributing for the development of this study, mainly: S&P Clever Reinforcement Ibérica Lda., Artecanter - Indústria de Transformação de Granitos, Lda., Vialam – Indústrias Metalúrgicas e Metalomecânicas, Lda.info:eu-repo/semantics/publishedVersio

Evaluation of OpenMP for the Cyclops multithreaded architecture

Multithreaded architectures have the potential of tolerating large memory and functional unit latencies and increase resource utilization. The Blue Gene/Cyclops architecture, being developed at the IBM T. J. Watson Research Center, is one such systems that offers massive intra-chip parallelism. Although the BG/C architecture was initially designed to execute specific applications, we believe that it can be effectively used on a broad range of parallel numerical applications. Programming such applications for this unconventional design requires a significant porting effort when using the basic built-in mechanisms for thread management and synchronization. In this paper, we describe the implementation of an OpenMP environment for parallelizing applications, currently under development at the CEPBA-IBM Research Institute, targeting BG/C. The environment is evaluated with a set of simple numerical kernels and a subset of the NAS OpenMP benchmarks. We identify issues that were not initially considered in the design of the BG/C architecture to support a programming model such as OpenMP. We also evaluate features currently offered by the BG/C architecture that should be considered in the implementation of an efficient OpenMP layer for massive intra-chip parallel architectures.Peer ReviewedPostprint (author's final draft

Gamma Spectrometry results for the 134Cs nuclear parameters / Resultados de espectrometria gama para os parâmetros nucleares 134Cs

134Cs is produced directly as a fission product (low yield) and too obtained by neutron capture from 133Cs non-radioactive . The National Laboratory for Ionizing Radiation Metrology (LNMRI/IRD/CNEN) of Rio de Janeiro performed standardization of this radionuclide . A solution of 134Cs radionuclide was purchased from commercial supplier to nuclear parameters determination such as activity and emission probabilities of some of its energies. 134Cs is a beta gamma emitter with 754 days of half-life. This radionuclide is used as standard in environmental, water and food control. It is also  important to germanium detector calibration The gamma emission probabilities were determined mainly for some energies of the 134Cs by efficiency curve method and the mostly  uncertainties obtained were around 1.5 %

Fast Matrix Multiplication via Compiler-only Layered Data Reorganization and Intrinsic Lowering

The resurgence of machine learning has increased the demand for high-performance basic linear algebra subroutines (BLAS), which have long depended on libraries to achieve peak performance on commodity hardware. High-performance BLAS implementations rely on a layered approach that consists of tiling and packing layers, for data (re)organization, and micro kernels that perform the actual computations. The creation of high-performance micro kernels requires significant development effort to write tailored assembly code for each architecture. This hand optimization task is complicated by the recent introduction of matrix engines by IBM's POWER10 MMA, Intel AMX, and Arm ME to deliver high-performance matrix operations. This paper presents a compiler-only alternative to the use of high-performance libraries by incorporating, to the best of our knowledge and for the first time, the automatic generation of the layered approach into LLVM, a production compiler. Modular design of the algorithm, such as the use of LLVM's matrix-multiply intrinsic for a clear interface between the tiling and packing layers and the micro kernel, makes it easy to retarget the code generation to multiple accelerators. The use of intrinsics enables a comprehensive performance study. In processors without hardware matrix engines, the tiling and packing delivers performance up to 22x (Intel), for small matrices, and more than 6x (POWER9), for large matrices, faster than PLuTo, a widely used polyhedral optimizer. The performance also approaches high-performance libraries and is only 34% slower than OpenBLAS and on-par with Eigen for large matrices. With MMA in POWER10 this solution is, for large matrices, over 2.6x faster than the vector-extension solution, matches Eigen performance, and achieves up to 96% of BLAS peak performance

Bond behaviour of NSM CFRP-concrete systems: adhesive and CFRP cross-section influences

Near Surface Mounted (NSM) strengthening technique has been used in a sustainable way for retrofitting existing structures. This technique, which utilizes CFRP laminates inserted in the concrete cover, has been used due to the several advantages when compared with the technique based on the application of these reinforcing materials on the concrete surface (EBR technique). Although several studies have been developed on this topic in the recent past, open issues still deserve research, such as the influence of the adhesive type on the performance of the NSM-CFRP system. The present work details an experimental program carried out in order to assess the effect of using three adhesives with distinct mechanical properties on the bond behavior of the NSM-CFRP system, through direct pullout tests (DPT). Thus, the following variables were considered in the present study: (i) the type of adhesive; (ii) the cross section of the laminate; and, (iii) the bond length. The experimental pullout force-slip responses were obtained and digital image correlation (DIC) was used for obtaining additional information about the bond mechanisms developed. In general, two of the three adhesives, with similar mechanical characteristics, provided essentially similar bond behavior, with high level of effectiveness, whereas the third adhesive, which had a much lower elastic modulus than the other two, provided the lowest effectiveness in terms of the investigated parameters.This work was supported by FEDER funds through the Operational Program for Competitiveness Factors – COMPETE and National Funds through FCT (Portuguese Foundation for Science and Technology) under the projects CutInDur FCOMP-01-0124-FEDER-014811 (FCT PTDC/ECM/112396/2009), FRPreDur FCOMP-01- 0124-FEDER-028865 (FCT PTDC/ECM-EST/2424/2012), FRPLongDur POCI-01-0145-FEDER-016900 (FCT PTDC/ECM-EST/1282/2014) and partly financed by the project POCI-01-0145-FEDER-007633.

Estudo da Sensibilização aos Aeroalergenos Phl p 1, Phl p 5, Ole e 1 e Ole e 2 em Doentes com Patologia Alérgica Sazonal

Estudo da Sensibilização aos Aeroalergenos Phl p 1, Phl p 5, Ole e 1 e Ole e 2 em Doentes com Patologia Alérgica Sazonal Cátia Coelho2, Elsa Caeiro2,4, Maria Luísa Lopes1, Ana Filipa Lopes3, Raquel Ferro2, José Eduardo Moreira3, Célia Antunes3,4, Rui Brandão4,5 1Hospital de Santa Luzia, Elvas, Portugal; 2Sociedade Portuguesa de Alergologia e Imunologia Clínica (SPAIC), Lisboa, Portugal; 3Departamento de Química, Universidade de Évora, Portugal; 4Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Portugal; 5 Departamento de Biologia, Universidade de Évora, Portugal Introdução: A sensibilização aos pólenes depende de vários factores nomeadamente do tipo de vegetação local e sabe-se que a sintomatologia não está apenas associada à exposição aos pólens mas também a partículas, algumas das quais resultantes da rotura dos grãos de pólen sendo posteriormente aerossolizadas. Objectivos: Relacionar a sensibilização de doentes com a concentração polínica atmosférica e a concentração de alguns dos respectivos aerolergenos. Métodos: Das consultas externas de Imunoalergologia dos hospitais de Évora e Elvas seleccionaram-se doentes que apresentavam queixas sazonais de rinite alérgica e asma brônquica, aos quais foram realizados testes cutâneos em Prick, standardizados, aos pólenes identificados na região. A 55 doentes foram realizados testes ao extracto de Phleum, aos seus alergénios Phl p 1 e Phl p 5, bem como aos extractos das restantes gramíneas e a 47 doentes foram realizados testes ao extracto de Olea, aos seus alergénios Ole e 1 e Ole e 2. Monitorizaram-se diariamente as partículas polínicas e os aeroalergenos mediante 2 colectores específicos para cada tipo. Resultados: A percentagem de doentes que é sensível aos 3 extractos de Phleum (Phleum total, Phl p 1 e Phl p 5) é de 51% , a dos que são sensíveis aos extractos de Phleum total e Phl p 1 é de 16 % e a dos que são sensíveis a Phleum total e Phl p5 é de 2%. A percentagem de doentes que é sensível a somente um dos extractos é de 20% e os que não têm qualquer sensibilidade são 11%. A percentagem de doentes que é sensível aos 3 extractos de Olea (Olea total, Ole e 1 e Ole e 2) é de 23%, a dos que são sensíveis à Olea total e Ole e 1 é de 21 % e a dos que são sensíveis à Olea total e Ole e 2 é de apenas 4%. A percentagem dos que são sensíveis a um dos extractos é de 19% e a dos que não apresentaram qualquer sensibilidade é de 32%. Conclusões: Podemos concluir que 89% dos doentes mostraram ser sensíveis aos alergénios da gramínea Phleum pratense pois mostraram positividade tanto ao extracto de Phleum e/ou aos seus alergénios Phl p 1 e Phl p 5. Em relação à oliveira, 44% dos doentes são alérgicos a este pólen pois são sensíveis ao seu alergénio major, Ole e 1. Em ambos os casos estão correlacionados com os aeroalergenos detectados nas amostras de ar, sendo a sensibilidade aos pólenes de gramíneas maior que a sensibilidade ao pólen de oliveira. Mais estudos devem ser realizados para despiste de reacções cruzadas nomeadamente quanto à Olea com outras plantas da região

Lean Green - A importância da integração do ambiente na filosofia Lean - Caso de estudo

A presente dissertação aborda a relação entre a indústria atual e o ambiente, revelando técnicas que permitem reduzir o impacto ambiental causado pelos seus processos de produção. Este trabalho é apoiado por um caso de estudo em que é utilizado o modelo de investigação Action Research e onde é realizada a identificação e quantificação do impacto económico e ambiental na integração dos conceitos Lean e Green numa empresa do setor da metalomecânica, e onde o principal foco de análise foi o processo de soldadura robotizada. Numa época em que há uma preocupação crescente com o meio ambiente e a sua preservação e, consequentemente, existe uma grande pressão para a redução de resíduos industriais, é fundamental que as empresas encontrem técnicas que permitam reduzir os seus desperdícios, sem que isso implique a redução dos seus ganhos económicos. Nesse contexto, a filosofia Lean surge como um conjunto de técnicas que, quando bem aplicadas, permitem que as organizações atinjam determinado objetivo com a utilização de menos recursos, energia e matérias-primas, concentrando-se na eliminação de resíduos e aumentando, ao mesmo tempo, a produtividade e qualidade dos seus produtos. Os resultados positivos, comprovados em diversos artigos na implementação da produção Lean, levam as pessoas a olharem para o Lean como uma filosofia de gestão capaz de reduzir o impacto ambiental dos sistemas de produção. No entanto, da revisão da literatura conclui-se que isso ainda não é consensual, e no caso de estudo deste trabalho, demonstra-se a importância da relação Lean/Green para o desempenho ambiental e económico das empresas com a implementação de quatro ferramentas e metodologias Lean: Kaizen, Jidoka, Total Productive Maintenance (TPM) e produção em células. A aplicação destas ferramentas e metodologias permitiu aumentar a eficiência do sistema de produção e reduzir o impacto ambiental da empresa em estudo, em que alguns dos resultados obtidos foram a redução em 25% dos tempos de ciclo do processo, em média, a redução do consumo de energia em 38% e a redução da sucata proveniente do processo em 66%. Os resultados revelaram uma relação positiva entre a utilização das técnicas Lean e a melhoria do desempenho ambiental da empresa.This dissertation discusses the relationship between the current industry and the environment and reveals techniques to reduce the environmental impact caused by manufacturing processes. This work is supported by a case study using the Action Research methodology. The identification and quantification of the economic and environmental impact in the integration of Lean and Green concepts in a metalworking company is carried out and the analysis focus was the robot welding process. At a time when there is a growing concern about the environment and its preservation and consequently there is a great pressure for an industrial waste reduction, it is essential for companies to find techniques that allow a waste reduction without reducing their economic gains. In this context, the Lean philosophy emerges as a set of techniques that, when well applied, allow organizations to achieve an objective by using less resources, energy and raw materials, focusing on eliminating waste and increasing productivity and product quality. The positive results proven in many articles in implementing Lean production lead people see Lean as a management philosophy that can reduce environmental impact of production systems. However, from the literature review it is concluded that this is still not consensual and in the case study it is demonstrated the importance of Lean/Green relation for the companies environmental and economic performance by implementing four Lean tools and methodologies: Kaizen, Jidoka, Total Productive Maintenance (TPM) and Cell Production. The application of these tools and methodologies increased the production efficiency and reduced the environmental impact of the company under study, where some of the results obtained were the cycle time reduction by 25%, the reduction of energy consumption by 38% and the reduction of scrap from the process by 66%. The results revealed a positive relationship between the use of Lean techniques and the improvement of the company's environmental performance

High volume exercise training in older athletes influences inflammatory and redox responses to acute exercise

To examine whether the volume of previous exercise training in older athletes influences inflammatory, redox, and hormonal profiles, 40 trained marathon runners were divided into higher-volume (HVG, ~480 min/week) and lower-volume groups (LVG, ~240 min/week). Plasma inflammatory proteins, redox biomarkers, salivary testosterone, and cortisol were assessed at restand following two maximal acute exercise bouts. At rest, the LVG exhibited higher CRP, higher protein carbonyls, and lower SOD activity compared to the HVG (p's &lt; .05). In response to exercise, TNF-a declined similarly in both groups whereas CRP increased differentially (+60% LVG; +24% HVG; p's &lt; .05). Protein carbonyls decreased and thiols increased similarly in both groups, but SOD declined differentially between groups (-14% LVG; -20% HVG; p's &lt; .05). Salivary testosterone decreased similarly in both groups, whereas cortisol did not change. A higher volume of training is associated with favorable inflammatory and redox profiles at rest, perhaps mediated by small inflammatory responses to acute exercise.</p