[1] The spread of mineral particles over southwestern, western, and central Europe resulting from a strong Saharan dust outbreak in October 2001 was observed at 10 stations of the European Aerosol Research Lidar Network (EARLINET). For the first time, an optically dense desert dust plume over Europe was characterized coherently with high vertical resolution on a continental scale. The main layer was located above the boundary layer (above 1-km height above sea level (asl)) up to 3-5-km height, and traces of dust particles reached heights of 7-8 km. The particle optical depth typically ranged from 0.1 to 0.5 above 1-km height asl at the wavelength of 532 nm, and maximum values close to 0.8 were found over northern Germany. The lidar observations are in qualitative agreement with values of optical depth derived from Total Ozone Mapping Spectrometer (TOMS) data. Ten-day backward trajectories clearly indicated the Sahara as the source region of the particles and revealed that the dust layer observed, e.g., over Belsk, Poland, crossed the EARLINET site Aberystwyth, UK, and southern Scandinavia 24-48 hours before. Lidar-derived particle depolarization ratios, backscatter-and extinction-related Å ngström exponents, and extinction-to-backscatter ratios mainly ranged from 15 to 25%, À0.5 to 0.5, and 40-80 sr, respectively, within the lofted dust plumes. A few atmospheric model calculations are presented showing the dust concentration over Europe. The simulations were found to be consistent with the network observations.
The determination of the depth of daytime and nighttime mixing layers must be known very accurately to relate boundary-layer concentrations of gases or particles to upstream fluxes. The mixing-height is parametrized in numerical weather prediction models, so improving the determination of the mixing height will improve the quality of the estimated gas and particle budgets. Datasets of mixing-height diurnal cycles with high temporal and spatial resolutions are sought by various end users. Lidars and ceilometers provide vertical profiles of backscatter from aerosol particles. As aerosols are predominantly concentrated in the mixing layer, lidar backscatter profiles can be used to trace the depth of the mixing layer. Large numbers of automatic profiling lidars and ceilometers are deployed by meteorological services and other agencies in several European countries providing systems to monito
Hardware and software of secured embedded systems are prone to physical attacks. In particular, fault injection attacks revealed vulnerabilities on the data and the control flow allowing an attacker to break cryptographic or secured algorithms implementations. While many research studies concentrated on successful attacks on the data flow, only a few targets the instruction flow. In this paper, we focus on electromagnetic fault injection (EMFI) on the control flow, especially on the instruction cache. We target the very widespread (smartphones, tablets, settop-boxes, health-industry monitors and sensors, etc.) ARMv7-M architecture. We describe a practical EMFI platform and present a methodology providing high control level and high reproducibility over fault injections. Indeed, we observe that a precise fault model occurs in up to 96% of the cases. We then characterize and exhibit this practical fault model on the cache that is not yet considered in the literature. We comprehensively describe its effects and show how it can be used to reproduce well known fault attacks. Finally, we describe how it can benefits attackers to mount new powerful attacks or simplify existing ones.
Abstract-Detecting hardware trojans is a difficult task in general. In this article we study hardware trojan horses insertion and detection in cryptographic intellectual property (IP) blocks. The context is that of a fabless design house that sells IP blocks as GDSII hard macros, and wants to check that final products have not been infected by trojans during the foundry stage. First, we show the efficiency of a medium cost hardware trojans detection method if the placement or the routing have been redone by the foundry. It consists in the comparison between optical microscopic pictures of the silicon product and the original view from a GDSII layout database reader. Second, we analyze the ability of an attacker to introduce a hardware trojan horse without changing neither the placement nor the routing of the cryptographic IP logic. On the example of an AES engine, we show that if the placement density is beyond 80%, the insertion is basically impossible. Therefore, this settles a simple design guidance to avoid trojan horses insertion in cryptographic IP blocks: have the design be compact enough, so that any functionally discreet trojan necessarily requires a complete re-place and re-route, which is detected by mere optical imaging (and not complete chip reverse-engineering).Index Terms-Hardware trojan horses (HTH), HTH detection and insertion, optical pictures versus GDSII comparison technique, ECO place-and-route, core utilization rate (CUR).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.