An exhaustive analysis of SEU effects in the SRAM memory of soft processor

International audienceThe Embedded system design is characterized by its daily complexity. It integrates a hardware and software parts together on a common platform. These parts may be defective by a spurious signal, subsequently found to be two types of errors. The software and hardware errors can attack the embedded system. In this paper an exhaustive analysis of the effects of Single Event Upset into the Static Random Access Memory occupied area of Aeroflex Gaisler LEON3 processor is presented. It is a soft core pipeline processor that is part of the GRLIB IP library based on Scalable Processor Architecture, SPARC V8, implemented in Virtex-5 FPGA. A new software methodology allowing fault injection is explored and illustrated in order to classify the defective behaviours while executing several benchmarks. This investigation is done by an exhaustive fault injection campaign (More than 200000 transient faults) into SRAM memory of LEON3 considered as a processor. The proposed method makes error rate predictions more accurate compared to other techniques

Effects of extraction solvents on phenolic contents and antioxidant activities of Tunisian date varieties (Phoenix dactylifera L.)

peer reviewedSecond-grade dates (Phoenix dactylifera L.), with hard texture, from six Tunisian cultivars were analysed for their composition and antioxidant activities. Results showed predominance of total sugars and a relatively low content of protein, fat andash. On the other hand, optimisation of extraction of antioxidant was carried using five different solvents. The highest level of phenolic compounds for all dates varieties was found in the 70% acetone extract. This level ranged from 199.43 to 576.48 mg of GAE/100 g fresh weight. However, extraction into 50% methanol gave the highest antioxidant activity from 89.55 to 109.67 mg equivalents of ascorbic acid/g fresh weight. For both two olvents, Bejo exhibited the highest phenolic content and total antioxidant activity, while Baydh El Hamam presented the owest. A positive linear correlation between total antioxidant activity and phenolic contents was observed (R2 = 0.83; R2 = 74 for acetone/H2O and methanol/H2O, respectively). The antioxidant activity of acetone/H2O and methanol/H2O extracts was carried using DPPH radical-scavenging activity and reducing power. These results showed that dates had strongly scavenging activity on DPPH reaching 90.12% in methanol/H2O from Deglet Nour. Whereas, acetone/H2O showed the best reducing power which Bejo was significantly higher than the other varieties. This study demonstrates the potential antioxidant activity with Tunisian date, that we can use these natural extracts as food additives in replacement of synthetic compounds

Badanie struktury mieszania w zbiorniku z mieszadłem w systemie wielowirnikowym z czteropłatkowymi wirnikami Rushtona

The effect of multiple Rushton impellers configurations on hydrodynamics and mixing performance in a stirred tank has been investigated. Three configurations defined by one, two and three Rushton impellers are compared. Results issued from our computational fluid dynamics (CFD) code are presented here concerning fields of velocity components and viscous dissipation rate. These results confirm that the multi-impellers systems are necessary to decrease the weaken zones in each stirred tanks. The experimental results developed in this work are compared with our numerical results. The good agreement validates the numerical method.W pracy badano efekt konfiguracji wielołopatkowych wirników Rushtona na hydrodynamikę i skuteczność mieszania w zbiorniku z mieszadłem. Porównano trzy konfiguracje mieszadła, zdefiniowane przez jeden, dwa lub trzy wirniki Rushtona. W artykule zaprezentowano wyniki, uzyskane przy użyciu własnego oprogramowania do obliczeń dynamiki płynów (CFD), dotyczące składników pól prędkości i szybkości dyssypacji lepkościowej. Wyniki te potwierdzają, że systemy wielowirnikowe są niezbędne dla zmniejszenia stref zubożonych w każdym zbiorniku z mieszadłem. Wyniki eksperymentalne, uzyskane w tej pracy, są porównane z wynikami obliczeń numerycznych. Dobra zgodność wyników potwierdza przydatność metody numerycznej

A trust architecture for blockchain in IoT

Blockchain is a promising technology for establishing trust in IoT networks, where network nodes do not necessarily trust each other. Cryptographic hash links and distributed consensus mechanisms ensure that the data stored on an immutable blockchain can not be altered or deleted. However, blockchain mechanisms do not guarantee the trustworthiness of data at the origin. We propose a layered architecture for improving the end-to-end trust that can be applied to a diverse range of blockchain-based IoT applications. Our architecture evaluates the trustworthiness of sensor observations at the data layer and adapts block verification at the blockchain layer through the proposed data trust and gateway reputation modules. We present the performance evaluation of the data trust module using a simulated indoor target localization and the gateway reputation module using an end-to-end blockchain implementation, together with a qualitative security analysis for the architecture.</p

Effect of processing conditions on phenolic compounds and antioxidant properties of date syrup

Commercial hydrolytic enzymes (pectinase and cellulase) were investigated for their influence on phenolics and antioxidant activities of date syrup. Content of total phenolics, flavonoids and carotenoids contents were determined spectrophotometrically. Polyphenols composition was examined using HPLC. Seven phenolic compounds (catechin, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid and sinapic acid) were detected in all date syrup extracts. p-Coumaric acid was the major compound of all date syrup extracts, representing 49.223-63.397%. The antioxidant activity of date syrup was evaluated by various antioxidant assays, including total antioxidant, DPPH scavenging test, FRAP, hydrogen peroxide scavenging activity and metal chelating activity.Results showed that the date syrup prepared after extraction with pectinase and cellulase mixture gave the lowest phenolic and flavonoid contents. For same variety, date syrup prepared after extraction with pectinase and cellulase mixture gave the highest carotenoids amounts. The antioxidant activity, determined by several methods, was significantly affected by the extraction method as well as date varieties. In fact, the date syrup prepared after extraction with pectinase and cellulase mixture gave the lowest antioxidant activity. A good correlation between the antioxidant activity and total phenolic content and flavonoid was observed. The discovery of our research is very important to scientists as well as to the fruit-processing industry to produce juice and syrup with high antioxidant activity. © 2012 Elsevier B.V