Selective SWIFT-R. A Flexible Software-Based Technique for Soft Error Mitigation in Low-Cost Embedded Systems

Commercial off-the-shelf microprocessors are the core of low-cost embedded systems due to their programmability and cost-effectiveness. Recent advances in electronic technologies have allowed remarkable improvements in their performance. However, they have also made microprocessors more susceptible to transient faults induced by radiation. These non-destructive events (soft errors), may cause a microprocessor to produce a wrong computation result or lose control of a system with catastrophic consequences. Therefore, soft error mitigation has become a compulsory requirement for an increasing number of applications, which operate from the space to the ground level. In this context, this paper uses the concept of selective hardening, which is aimed to design reduced-overhead and flexible mitigation techniques. Following this concept, a novel flexible version of the software-based fault recovery technique known as SWIFT-R is proposed. Our approach makes possible to select different registers subsets from the microprocessor register file to be protected on software. Thus, design space is enriched with a wide spectrum of new partially protected versions, which offer more flexibility to designers. This permits to find the best trade-offs between performance, code size, and fault coverage. Three case studies have been developed to show the applicability and flexibility of the proposal.

Imaging Land Subsidence Induced by Groundwater Extraction in Beijing (China) Using Satellite Radar Interferometry

Beijing is one of the most water-stressed cities in the world. Due to over-exploitation of groundwater, the Beijing region has been suffering from land subsidence since 1935. In this study, the Small Baseline InSAR technique has been employed to process Envisat ASAR images acquired between 2003 and 2010 and TerraSAR-X stripmap images collected from 2010 to 2011 to investigate land subsidence in the Beijing region. The maximum subsidence is seen in the eastern part of Beijing with a rate greater than 100 mm/year. Comparisons between InSAR and GPS derived subsidence rates show an RMS difference of 2.94 mm/year with a mean of 2.41 ± 1.84 mm/year. In addition, a high correlation was observed between InSAR subsidence rate maps derived from two different datasets (i.e., Envisat and TerraSAR-X). These demonstrate once again that InSAR is a powerful tool for monitoring land subsidence. InSAR derived subsidence rate maps have allowed for a comprehensive spatio-temporal analysis to identify the main triggering factors of land subsidence. Some interesting relationships in terms of land subsidence were found with groundwater level, active faults, accumulated soft soil thickness and different aquifer types. Furthermore, a relationship with the distances to pumping wells was also recognized in this work.

London, England, ca. 1676 (Raster Image)

This layer is a georeferenced raster image of the historic paper map entitled: Englands glory, or, the glory of England being a new mapp of the city of London : shewing the remarkable streets, lanes, alleyes, churches, halls courts, and other places as they are now rebuilt, the which will therefore be a guide to strangers, and such as are not well acquainted herein to direct them from place to place : diverse faults y[t] are in y[e] former are in this amended, allsoe the severall figures y[t] stand up and downe in the mapp are explained in y[e] 2 tables at y[e] upper corners hereof. It was published by Robert Walton ca. 1676. Scale [ca. 1:60,000]. The image inside the map neatline is georeferenced to the surface of the earth and fit to British National Grid coordinate system (British National Grid, Airy Spheroid OSGB (1936) Datum). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows features such as roads, drainage, built-up areas, selected buildings pictorially, fortification, docks, parks, ground cover, and more. Includes also indexes. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Structural evolution of the Lesser Himalayan fold-thrust belt of west central Nepal

The Lesser Himalayan fold-thrust belt on the south flank of the Jajarkot klippe in west central Nepal was mapped in detail between the Main Central thrust in the north and the Main Boundary thrust in the south. South of the Jajarkot klippe, the fold-thrust belt involves sandstone, shale and carbonate rocks that are unmetamorphosed in the foreland and increase in metamorphic grade with higher structural position to sub-greenschist facies towards the hinterland. The exposed stratigraphy is correlative with the Proterozoic Ranimata, Sangram, Galyang, Syangia Formations and Lakharpata Group of Western Nepal and overlain by the Paleozoic Tansen and Kali Gandaki Groups. Based on field mapping and cross-section construction, three distinct thrust sheets were identified separated by top-to-the-south thrust faults. From the foreland (south) to the hinterland (north), the first thrust sheet in the immediate hanging wall of the Main Boundary thrust defines an open syncline. The second thrust sheet contains a very broad synformal duplex, which is structurally stacked against the third thrust sheet containing a homoclinal panel of the oldest exposed Proterozoic stratigraphy. Outcrop scale folds throughout the study area are predominantly south vergent, open, and asymmetric reflecting the larger regional scale folding style, which corroborate the top-to-the-south deformation style seen in the faults of the region. Field techniques were complemented with microstructural and quartz crystallographic c-axis preferred orientation analyses using a petrographic microscope and a fabric analyzer, respectively. Microstructural analysis identified abundant strain-induced recrystallization textures and occasional occurrences of top-to-the-south shear-sense indicators primarily in the hinterland rocks in the immediate footwall of the Main Central Thrust. Top-to-the-south shearing is also supported by quartz crystallographic c-axis preferred orientations. Quartz recrystallization textures indicate an increase in deformation temperature towards the Main Central thrust. A line balance estimate indicates that approximately 15 km of crustal shortening was accommodated by folding and faulting in the fold-thrust belt south of the Jajarkot klippe. Additionally, estimations of shortening velocity suggest that the shortening velocity operating in this section of the fold-thrust belt between 23 to 14 Ma was slower than what is currently observed as a result of the ongoing deformation of the Sub-Himalayan fold-thrust belt.

Tectonic geomorphology assessment of the Ken River catchment near Panna, Madhya Pradesh, India

This thesis focuses on tectonic geomorphology and the response of the Ken River catchment to postulated tectonic forcing along a NE-striking monocline fold in the Panna region, Madhya Pradesh, India. Peninsular India is underlain by three northeast-trending paleotopographic ridges of Precambrian Indian basement, bounded by crustal-scale faults. Of particular interest is the Pokhara lineament, a crustal scale fault that defines the eastern edge of the Faizabad ridge, a paleotopographic high cored by the Archean Bundelkhand craton. The Pokhara lineament coincides with the monocline structure developed in the Proterozoic Vindhyan Supergroup rocks along the Bundelkhand cratonic margin. A peculiar, deeply incised meander-like feature, preserved along the Ken River where it flows through the monocline, may be intimately related to the tectonic regime of this system. This thesis examines 41 longitudinal stream profiles across the length of the monocline structure to identify any tectonic signals generated from recent surface uplift above the Pokhara lineament. It also investigates the evolution of the Ken River catchment in response to the generation of the monocline fold. Digital Elevation Models (DEM) from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) were used to delineate a series of tributary watersheds and extract individual stream profiles which were imported into MATLAB for analysis. Regression limits were chosen to define distinct channel segments, and knickpoints were defined at breaks between channel segments where there was a discrete change in the steepness of the channel profile. The longitudinal channel profiles exhibit the characteristics of a fluvial system in transient state. There is a significant downstream increase in normalized steepness index in the channel profiles, as well as a general increase in concavity downstream, with some channels exhibiting convex, over-steepened segments. Normalized steepness indices and uppermost knickpoint elevations are on average much higher in streams along the southwest segment of the monocline compared to streams along the northeast segment. Most channel profiles have two to three knickpoints, predominantly exhibiting slope-break morphology. These data have important implications for recent surface uplift above the Pokhara lineament. Furthermore, geomorphic features preserved along the Ken River suggest that it is an antecedent river. The incised meander-like feature appears to be the abandoned river valley of a former Ken River course that was captured during the evolution of the landscape by what is the present day Ken River.

Avaliação do desempenho do sistema de mini-geração fotovoltaico na Faculdade de Ciências

Tese de mestrado integrado, Engenharia da Energia e do Ambiente, Universidade de Lisboa, Faculdade de Ciências, 2016

InterInterpretação das lesões ortopédicas dos ocupantes dos veículos na reconstrução forense dos acidentes de viação

Road Traffic accidents are the leading cause of violent death and a major cause of death and sequelae in young and economically active population in developed and developing countries. Numbers that can only be compared to wars, which exemplifies the consequences of these lesions in economic and social terms. In 2002, about 1.2 million people died in traffic accidents, and in 2020, it is estimated that this number will double according to the World Health Organization (WHO). Only a small percentage of these are generated by vehicle faults or adverse conditions. The vast majority of accidents are caused by carelessness, negligence or malpractice of drivers or pedestrians, which makes the reconstruction of accidents a key step in the investigation and prevention of further accidents.

Fault diagnosis of an automotive suspension system

With the development of the embedded application and driving assistance systems, it becomes relevant to develop parallel mechanisms in order to check and to diagnose these new systems. In this thesis we focus our research on one of this type of parallel mechanisms and analytical redundancy for fault diagnosis of an automotive suspension system. We have considered a quarter model car passive suspension model and used a parameter estimation, ARX model, method to detect the fault happening in the damper and spring of system. Moreover, afterward we have deployed a neural network classifier to isolate the faults and identifies where the fault is happening. Then in this regard, the safety measurements and redundancies can take into the effect to prevent failure in the system. It is shown that The ARX estimator could quickly detect the fault online using the vertical acceleration and displacement sensor data which are common sensors in nowadays vehicles. Hence, the clear divergence is the ARX response make it easy to deploy a threshold to give alarm to the intelligent system of vehicle and the neural classifier can quickly show the place of fault occurrence.

Sandbox experiments on basin inversion: testing the influence of basin orientation and basin fill

Analogue modelling experiments using brittle materials are performed to study the inversion of extensional structures. Asymmetric grabens of two different orientations are first created during a phase of extension and progressively filled. They are subsequently shortened in the same direction. The aim of our experiments is to determine factors affecting the style of deformation during inversion. We specifically investigate variations in thickness and distribution of strong and weak layers constituting the graben fill and in initial basin orientation. The main advantage of our experimental set-up is that we have a complete control on graben location, width, infill and orientation before inversion. The experiments show that shortening results only in limited reactivation of pre-existing normal faults. In general, forward thrusts and backthrusts cut across normal faults into the footwall of the graben. The forward thrusts either propagate parallel to the enveloping surface of faulted blocks or they cut across basin-limiting normal faults at various angles. The graben fill is mechanically extruded by displacement along forward thrusts that accommodate most of the shortening. Both pre-existing faults and weak graben fill act as zones of weakness during inversion and determine the orientation and location of both backthrusts and forward thrusts. The results of our experiments conform well to natural examples of inverted graben structures.

Comparisons between analogue and numerical models of thrust wedge development

Analogue and finite element numerical models with frictional and viscous properties are used to model thrust wedge development. Comparison between model types yields valuable information about analogue model evolution, scaling laws and the relative strengths and limitations of the techniques. Both model types show a marked contrast in structural style between ‘frictional-viscous domains’ underlain by a thin viscous layer and purely ‘frictional domains’. Closely spaced thrusts form a narrow and highly asymmetric fold-and-thrust belt in the frictional domain, characterized by in-sequence propagation of forward thrusts. In contrast, the frictional-viscous domain shows a wide and low taper wedge and a thrust belt with a more symmetrical vergence, with both forward and back thrusts. The frictional-viscous domain numerical models show that the viscous layer initially simple shears as deformation propagates along it, while localized deformation resulting in the formation of a pop-up structure occurs in the overlying frictional layers. In both domains, thrust shear zones in the numerical model are generally steeper than the equivalent faults in the analogue model, because the finite element code uses a non-associated plasticity flow law. Nevertheless, the qualitative agreement between analogue and numerical models is encouraging. It shows that the continuum approximation used in numerical models can be used to model frictional materials, such as sand, provided caution is taken to properly scale the experiments, and some of the limitations are taken into account.

An insight into the breakup of Gondwana: Identifying events through low-temperature thermochronology from the basement rocks of Madagascar

Fission track analysis was applied to the Precambrian suites of Madagascar in order to identify the lower-temperature cooling histories and their relationships to the Phanerozoic events that affected the island. Apatite ages range from 431 to 68 Ma, and zircon ages range from 452 to 238 Ma. Thermochronologically, the island can be divided into a southern, central, and northern region each with a subdivision on an east-west basis. The southern region is sharply separated from the central region by strongly contrasting apparent apatite ages over the northwest-southeast striking Ranotsara Shear Zone (RSZ). The change in apparent ages over the RSZ is indicative of later reactivation along younger brittle faults. The central region has the oldest ages of the island and has a diffuse contact to the third region northward. Along the entire western margin of the Precambrian basement initial Paleozoic exhumation was followed by heating (burial by sediments) during Jurassic and Cretaceous times. A decrease in ages along the eastern margin from 119 to 68 Ma coincides with the predicted positions of the Marion hot spot after effects of erosion are considered. On the other hand, these ages may represent progressive opening of the margin in a southward direction together with associated denudation of the rift shoulder. The eastern part of the central region has remained very stable since at least Devonian times, undergoing only long-term very slow exhumation at rates of 1–5 m/Myr.

Fault development and interaction in distributed strike-slip shear zones: an experimental approach

Analogue model experiments using both brittle and viscous materials were performed to investigate the development and interaction of strike-slip faults in zones of distributed shear deformation. At low strain, bulk dextral shear deformation of an initial rectangular model is dominantly accommodated by left-stepping, en echelon strike-slip faults (Riedel shears, R) that form in response to the regional (bulk) stress field. Push-up zones form in the area of interaction between adjacent left-stepping Riedel shears. In cross sections, faults bounding push-up zones have an arcuate shape or merge at depth. Adjacent left-stepping R shears merge by sideways propagation or link by short synthetic shears that strike subparallel to the bulk shear direction. Coalescence of en echelon R shears results in major, through-going faults zones (master faults). Several parallel master faults develop due to the distributed nature of deformation. Spacing between master faults is related to the thickness of the brittle layers overlying the basal viscous layer. Master faults control to a large extent the subsequent fault pattern. With increasing strain, relatively short antithetic and synthetic faults develop mostly between old, but still active master faults. The orientation and evolution of the new faults indicate local modifications of the stress field. In experiments lacking lateral borders, closely spaced parallel antithetic faults (cross faults) define blocks that undergo clockwise rotation about a vertical axis with continuing deformation. Fault development and fault interaction at different stages of shear strain in our models show similarities with natural examples that have undergone distributed shear.

Stable isotope ratios of interstitial fluids from ODP Leg 110 sites

Delta18O values of pore waters from the northern Barbados accretionary prism range from -0.3 to -3.6? and reflect pervasive reaction of volcanic ash to form smectite within the sedimentary sequence and continued low temperature alteration of basalt in the underlying ocean crust with the overprint of diffusive exchange between water in the sediment pores and the open ocean. Delta D values of pore waters in sediments sampled seaward of the deformation front drop from +5? at the sediment surface to -6? at the deepest levels sampled. These changes may also be related to alteration processes but remain largely enigmatic. Sediment deformation caused by impingement of the Caribbean plate on the Atlantic plate has instigated migration of chemically and isotopically distinct fluid along faults and coarse-grained sedimentary beds; delta18O values of pore waters are also locally affected by thrust stacking which increases diffusive pathlengths and possibly modifies diagenetic reaction rates in Pleistocene sediments. Migrating fluids are distinguished by anomalous delta18O values that are as much as 1? higher than those of surrounding fluids. Uncertainties in hydrogen isotope fractionation resulting from processes occurring under these conditions hinder identification of the hydrogen isotope composition of expelled fluid. Stable isotope analyses of pore waters help constrain the fluid migration history of the accretionary prism by limiting the source of fluids, the paths along which fluid flows, and the timing of faulting and subsequent fluid flow.

Lithium isotopic composition of pore fluids and sediments in the Costa Rica subduction zone

Pore fluid and sediment Li concentrations and isotopic ratios provide important insights on the hydrology, sediment contribution to the arc volcanoes and fluid-sediment reactions at the dominantly non-accretionary Costa Rica subduction zone. Ocean Drilling Program Site 1039 in the trench axis provides a reference section of 400 m of the incoming sediments, and Site 1040, situated arcward from the trench, consists of a deformed sedimentary wedge and apron sediments, the décollement, and the partially dewatered underthrust sediment section. At the reference site, pore fluids show important isotopic variations (delta6Li=-21.7 to -37.8 per mil), reflecting the interplay of in situ alteration of volcanic material and ion exchange with clay minerals. In the basal section, a reversal of Li concentration and delta6Li toward seawater values is observed, providing supporting evidence for a lateral seawater flow system in the upper oceanic basement underlying this sediment section. At Site 1040, pore fluid of the lower deformed wedge sediments and within the décollement is enriched in Li and the isotopic compositions are relatively light, suggesting infiltration of a deep-seated fluid. The delta6Li value of -22 per mil of this Li-enriched fluid (261 µM), when compared with the delta6Li value of the subducted sediment section (-11 per mil), suggests that the deep source fluid originates from mineral fluid dehydration and transformation reactions at temperatures of 100 to 150°C, consistent with the temperature range of the up-dip seismogenic zone and of transformation of smectite to illite. The distribution of Li and its isotopes in the underthrust section are similar to those at the reference site, indicating near complete subduction of the incoming sediments and that early dewatering of the underthrust sediments occurs predominantly by lateral flow into the ocean. The hemipelagic clay-rich sediment section of the subducting plate carries most of the Li into this subduction zone, and the pelagic diatomaceous and nannofossil calcareous oozes contain little Li. The Li isotopes of both the clay-rich hemipelagic sediments and of the pelagic oozes are, however, similar, with delta6Li values of -9 to -12 per mil. The observations that (1) the delta6Li values of the underthrust sediments are distinctly lower than that of the mantle, and (2) the lavas of the Costa Rican volcanoes are enriched in Li and 7Li, provide an approximation of the contribution of the subducted sediments to the arc volcanoes. A first order mass balance calculation suggests that approximately half of the Li flux delivered by subducted sediments and altered oceanic crust into the Middle American Trench is recycled to the Costa Rican arc and at most a quarter of sedimentary Li is returned into the ocean through thrust faults, primarily the décollement thrust.

Mineral and chemical composition of hydrothermally altered rocks and sediments from the Middle Valley, ODP Leg 139 data

The Middle Valley segment at the northern end of the Juan de Fuca Ridge is a deep extensional rift blanketed with 200-500 m of Pleistocene turbiditic sediment. Sites 857 and 858 were drilled during Ocean Drilling Program Leg 139 to determine whether these two sites were hydrologically linked end members of an active hydrothermal circulation system. Site 858 was placed in an area of active hydrothermal discharge with fluids up to 270°C venting through anhydrite-bearing mounds on top of altered sediment. The shallow basement of fine-grained basalt that underlies the vents at Site 858 is interpreted as a seamount that was subsequently buried by turbidites. Site 857 was placed 1.6 km south of the Site 858 vents in a zone of high heat flow and numerous seismically imaged ridge-parallel faults. Drilling at Site 857 encountered sediments that are increasingly altered with depth and that overlie a series of mafic sills at depths of 460-940 m below sea floor. Sill margins and adjacent baked sediment are highly altered to magnesian chlorite and crosscut with veins filled with quartz, chlorite, sulfides, epidote, and wairakite. The sill interiors vary from slightly altered, with unaltered plagioclase and clinopyroxene in a mesostasis replaced by chlorite, to local zones of intense alteration and brecciation. In these latter zones, the sill interiors are pervasively replaced by chlorite, epidote, quartz, pyrite, titanite, and rare actinolite. The most complete replacement is associated with brecciated horizons with low recovery and slickensides on fracture surfaces, which we interpret as intersections between faults and the sills. Geochemically, the alteration of the sill complex is reflected in significant whole-rock depletions in Ca, Sr, and Na with corresponding enrichments in Mg, Al, and most metals. The latter results from the formation of conspicuous sulfide poikiloblasts. In contrast, metamorphism of the Site 858 seamount includes incomplete albitization of plagioclase phenocrysts and replacement of sparse mafic phenocrysts. Much of the basement alteration at Site 858 is confined to crosscutting veins except for a highly altered and veined horizon at the contact between basaltic basement and the overlying sediment. The sill complex at Site 857 is more highly depleted in 18O (d18O = 2.4 per mil - 4.7 per mil) and more pervasively replaced by secondary minerals relative to the extrusives at Site 858 (d18O = 4.5 per mil - 5.5 per mil). There is no evidence of significant albitization of the plagioclase at Site 857, suggesting high Ca/Na in the pore fluids. Fluid-inclusion data from hydrothermal minerals in altered mafic rocks and veins at Sites 857 and 858 show a consistency of homogenization temperatures, varying from 245 to 270°C, which is within the range of temperatures observed for the fluids venting at Site 858. The consistency of the fluid inclusion temperatures, the lack of albitization within the Site 857 sills, and the apparently low water/rock ratio collectively suggest that the sill complex at Site 857 is in thermal equilibrium and being altered by a highly evolved Ca-rich fluid similar to the fluids now venting at Site 858. The alteration evident in these two deep crustal drillsites is a result of the ongoing hydrothermal circulation and is consistent with downhole logging results, instrumented borehole results, and hydrothermal fluid chemistry. The pervasive alteration of the laterally extensive sill-sediment complex at Site 857 determines the chemistry of the fluids that are venting at Site 858. The limited alteration of the Site 858 lavas suggests that this basement edifice acts as a penetrator or ventilator for the regional hydrothermal reservoir with much of the flow focussed at the highly altered and veined sediment-basalt contact.