Mitigating smart card fault injection with link-time code rewriting: a feasibility study

We present a feasibility study to protect smart card software against fault-injection attacks by means of binary code rewriting. We implemented a range of protection techniques in a link-time rewriter and evaluate and discuss the obtained coverage, the associated overhead and engineering effort, as well as its practical usability

Linux kernel compaction through cold code swapping

There is a growing trend to use general-purpose operating systems like Linux in embedded systems. Previous research focused on using compaction and specialization techniques to adapt a general-purpose OS to the memory-constrained environment, presented by most, embedded systems. However, there is still room for improvement: it has been shown that even after application of the aforementioned techniques more than 50% of the kernel code remains unexecuted under normal system operation. We introduce a new technique that reduces the Linux kernel code memory footprint, through on-demand code loading of infrequently executed code, for systems that support virtual memory. In this paper, we describe our general approach, and we study code placement algorithms to minimize the performance impact of the code loading. A code, size reduction of 68% is achieved, with a 2.2% execution speedup of the system-mode execution time, for a case study based on the MediaBench II benchmark suite

The Alteration History of Clovis Class Rocks in Gusev Crater as Determined by Ti-Normalzed Mass Balance Analysis

The West Spur Clovis class rocks in Gusev Crater are some of the most altered rocks in Gusev Crater and likely contain a mixed sulfate and phyllosilicate mineralogy [1,2]. The high S and Cl content of the Clovis rocks suggests that acidic vapors or fluids of H2SO4 and HCl reacted with the Clovis parent rock to form Ca, Mg,- sulfates, iron-oxyhydroxides and secondary aluminosilicates (approx.60 wt.%) of a poorly crystalline nature (e.g., allophane) [1]. Up to 14-17 wt.% phyllosilicates (e.g., kaolinite, chlorite, serpentine) are hypothesized to exist in the Clovis materials suggesting that Clovis parent materials while possibly exposed to acidic pHs were likely neutralized by basalt dissolution which resulted in mildly acidic pHs (4-6) [1, 2]. This work proposes that subsequent to the alteration of the Clovis rocks, alteration fluids became concentrated in ions resulting in the addition of silicate and salts. The objective of this work is to utilize Ti-normalized mass balance analysis to evaluate (1) mineral gains and losses and (2) elemental gains and losses in the Clovis rocks. Results of this work will be used evaluate the nature of geochemical conditions that affect phyllosilicate and sulfate formation at Gusev crater

Evidence of silicene in honeycomb structures of silicon on Ag(111)

In the search for evidence of silicene, a two-dimensional honeycomb lattice of silicon, it is important to obtain a complete picture for the evolution of Si structures on Ag(111), which is believed to be the most suitable substrate for growth of silicene so far. In this work we report the finding and evolution of several monolayer superstructures of silicon on Ag(111) depending on the coverage and temperature. Combined with first-principles calculations, the detailed structures of these phases have been illuminated. These structure were found to share common building blocks of silicon rings, and they evolve from a fragment of silicene to a complete monolayer silicene and multilayer silicene. Our results elucidate how silicene formes on Ag(111) surface and provide methods to synthesize high-quality and large-scale silicene.Comment: 6 pages, 4 figure

The Formation of Fe/Mg Smectite Under Mildly Acidic Conditions on Early Mars

The detection of Fe/Mg smectites and carbonate in Noachian and early Hesperian terrain of Mars has been used to suggest that neutral to mildly alkaline conditions prevailed during the early history of Mars. However, if early Mars was neutral to moderately alkaline with a denser CO2 atmosphere than today, then large carbonates deposits should be more widely detected in Noachian terrain. The critical question is: Why have so few carbonate deposits been detected compared to Fe/Mg smectites? We suggest that Fe/Mg smectites on early Mars formed under mildly acidic conditions, which would inhibit the extensive formation of carbonate deposits. The goal of this work is to evaluate the formation of Fe/Mg smectites under mildly acidic conditions. The stability of smectites under mildly acidic conditions is attributed to elevated Fe/Mg activities that inhibit smectite dissolution. Beidelite and saponite have been shown to form from hydrothermal alteration of basaltic glass at pH 3.5-4.0 in seawater solutions. Nontronite is also known to be stable in mildly acidic systems associated with mafic and ultramafic rock. Nontronite was shown to form in acid sulfate soils in the Bangkok Plain, Thailand due to oxidation of Fe-sulfides that transformed saponite to nontronite. Smectite is known to transform to kaolinite in naturally acid soils due to selective leaching of Mg. However, if Mg removal is limited, then based on equilibrium relationships, the dissolution of smectite should be minimized. If Fe and Mg solution activities are sufficiently high, such as might be found in a low water/rock ratio system that is poorly drained, smectite could form and remain stable under mildly acidic conditions on Mars. The sources of mild acidity on early Mars includes elevated atmospheric CO2 levels, Fe-hydrolysis reactions, and the presence of volcanic SO2 aerosols. Equilibrium calculations dictate that water equilibrated with an early Mars CO2 atmosphere at 1 to 4 bar yields a pH of 3.6 to 3.9. Fe hydrolysis reactions on Mars is another source of protons that would have contributed to acidity. The presence of SO2 from volcanic processes could also have contributed to geochemical acidification. These sources of acidity competed with base-forming cations that resulted in mildly acidic solutions that were not favorable for carbonate formation but may have allowed for Fe/Mg smectite formation. Noachian to early Hesperian Mars could have been mildly acidic, allowing Fe/Mg smectite formation but preventing widespread carbonate deposition. This paradigm shift from an early Mars that was neutral-alkaline to mildly acidic may possibly explain why there is a disparity between the occurrence of carbonate and Fe/Mg smectites. Potential microbiological activity would not be eliminated under a mildly acidic Mars; however, there could be tighter constraints as to the type and species of microbiology that could exist

It is Hobbes, not Rousseau:an experiment on voting and redistribution

We perform an experiment which provides a laboratory replica of some important features of the welfare state. In the experiment, all individuals in a group decide whether to make a costly effort, which produces a random (independent) outcome for each one of them. The group members then vote on whether to redistribute the resulting and commonly known total sum of earnings equally amongst themselves. This game has two equilibria, if played once. In one of them, all players make effort and there is little redistribution. In the other one, there is no effort and nothingWe thank Iris Bohnet, Tim Cason, David Cooper, John Duffy, Maia Guell, John Van Huyck and Robin Mason for helpful conversations and encouragement. The comments of the Editor and two referees helped improve the paper. We gratefully acknowledge the financial support from Spain’s Ministry of Science and Innovation under grants CONSOLIDER INGENIO 2010 CSD2006-0016 (all authors), ECO2009-10531 (Cabrales), ECO2008-01768 (Nagel) and the Comunidad de Madrid under grant Excelecon (Cabrales), the Generalitat de Catalunya and the CREA program (Nagel), and project SEJ2007-64340 of Spain’s Ministerio de Educación y Ciencia (Rodríguez Mora).Publicad

Column Experiments to Interpret Weathering in Columbia Hills

Phosphate mobility has been postulated as an indicator of early aqueous activity on Mars. In addition, rock surfaces analyzed by the Mars Exploration Rover Spirit are consistent with the loss of a phosphate- containing mineral To interpret phosphate alteration behavior on Mars, we performed column dissolution experiments leaching the primary phases Durango fluorapatite, San Carlos olivine, and basalt glass (Stapafjell Volcano, courtesy of S. Gislason, University of Iceland) [3,4]) with acidic solutions. These phases were chosen to represent quickly dissolving phases likely present in Columbia Hills. Column dissolution experiments are closer to natural dissolution conditions than batch experiments, although they can be difficult to interpret. Acidic solutions were used because the leached layers on the surfaces of these rocks have been interpreted as resulting from acid solutions [5]

Perturbative calculation of the scaled factorial moments in second-order quark-hadron phase transition within the Ginzburg-Landau description

The scaled factorial moments $F_q$ are studied for a second-order quark-hadron phase transition within the Ginzburg-Landau description. The role played by the ground state of the system under low temperature is emphasized. After a local shift of the order parameter the fluctuations are around the ground state, and a perturbative calculation for $F_q$ can be carried out. Power scaling between $F_q$'s is shown, and a universal scaling exponent $\nu\simeq 1.75$ is given for the case with weak correlations and weak self-interactions.Comment: 12 pages in RevTeX, 12 eps figure