4,592 research outputs found

    Differential electromagnetic attack on an FPGA implementation of elliptic curve cryptosystems

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    This paper describes a differential electromagnetic analysis attack performed on a hardware implementation of an elliptic curve cryptosystem. We describe the use of the distance of mean test. The number of measurements needed to get a clear idea of the right guess of the key-bit is taken as indication of the success of the attack. We can find the right key-bit by using only 2000 measurements. Also we give a electromagnetic model for the FPGA we use in our experiments. The amplitude, the direction and the position of the current on the FPGA’s lines with respect to the position of the antenna have an influence on the measured electromagnetic radiation in the FPGA’s surrounding area

    Odour nuisance in Scheldt branch Gentbrugge-Melle [POSTER]

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    The tidal branch of the Sea Scheldt between the lock of Gentbrugge and Melle - part of the complex Ringvaart system around Ghent - has not received any upstream discharge since 1981. Consequently, ebb velocities were reduced, while flood velocities were left unaffected, causing sedimentation in the branch. At some locations along the branch, odour nuisance was regularly reported. In order to address the problem, Division Sea Scheldt of the Flemish Government proposed to dredge the associated muddy material. Flanders Hydraulics Research (FHR) was asked to conduct a study about the necessary upstream discharge at the lock of Gentbrugge needed to ensure the river branch’s self-erosiveness. To answer this question, monitored data were combined with modelling know-how. A 2D numerical morphological model was constructed, for which hydrological and sedimentological parameters, such as discharge, gauge height and sediment concentration, were used as input and for validation. All of these data were provided by FHR. After numerous numerical scenarios, it was concluded that the discharge required, lies between 20 and 25 m3/s. However, as a mean discharge of about 70 m3/s is discharged into the entire water system around Ghent, and as other waterways within this system require sufficient discharges (of which the Canal Ghent-Terneuzen has been determined in a Belgian-Dutch treaty) this discharge is not available in normal circumstances in the tidal branch. Currently, Flanders Hydraulics Research is investigating the possibilities of a lower discharge at the weir of Gentbrugge, that would allow to maintain the branch with a limited dredging

    Effects of GM potato Modena on soil microbial activity and litter decomposition fall within the range of effects found for two conventional cultivars

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    Plant roots have a profound effect on soil microbial activity, particularly in the rhizosphere. Hence, it is important to understand the potential effects of genetically modified (GM) crops on soil microbial activity and related processes such as litter decomposition. In this study, we compared the effects of GM potato Modena on soil microbial activity and carbon (C) and nitrogen (N) mineralization to effects induced by Modena’s parental isoline (Karnico) and a conventional potato cultivar (Aventra). A field experiment was conducted at two sites to assess microbial catabolic diversity (using MicroRespTM) in the rhizosphere and in bulk soil, during flowering and senescence of the potato plants. In a laboratory experiment with soil and potato litter from the field experiment, we investigated whether the cultivars had modified the activity of soil microbial communities to such an extent that this affected C and N mineralization. Results of the field experiment showed no GM-induced effects on microbial catabolic diversity, while effects of field site location and sampling date were significant. Multivariate analysis including plant traits and soil characteristics revealed that microbial catabolic activities in rhizosphere soil were strongly correlated with soil organic matter and tuber sucrose content, whereas in bulk soil, they were primarily correlated with soil moisture. In the laboratory experiment, we found that Modena induced a "home-field advantage" in N mineralization, yet this effect was inconsistent across locations and was also observed for other cultivars. Based on our data and results from previous studies, we conclude that the effects of GM cultivar Modena on soil microbial activity and litter decomposition fall within the normal range of effects found for conventional potato cultivars

    Optimal Design of Composite Structures by Advanced Mixed Integer Nonlinear Optimization

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    The objective of this case series study was reautomatization of gait after limb-saving surgery for tumors at a laboratory of gait analysis. Twelve patients (9 males and 3 females; mean age, 38 years) who underwent limb-saving surgery of the lower limb at least 1 year previously and ten normal subjects (3 males and 7 females; mean age, 37.5 years) were studied. The main outcome measures were walking speed and stride time duration under normal walking conditions as well as the use of different types of constraints. Patients walked with a lower preferred walking speed than the normal subjects. Patients showed a higher coefficient of variation of stride time in normal walking as well as complex walking compared with normal subjects. During walking with constraints, a significant decrease in stride time was found in patients but not in normal subjects. Although restoration of gait after limb-saving surgery is impressive, it is not complete (lower walking speed) and can break down under conditions of visual and cognitive load. Hence, the application of complex tasks reveals that gait reautomatization is not complete in these patients during a period of 2 to 5 years after surgery
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