5,954 research outputs found
A high speed Tri-Vision system for automotive applications
Purpose: Cameras are excellent ways of non-invasively monitoring the interior and exterior of vehicles. In particular, high speed stereovision and multivision systems are important for transport applications such as driver eye tracking or collision avoidance. This paper addresses the synchronisation problem which arises when multivision camera systems are used to capture the high speed motion common in such applications.
Methods: An experimental, high-speed tri-vision camera system intended for real-time driver eye-blink and saccade measurement was designed, developed, implemented and tested using prototype, ultra-high dynamic range, automotive-grade image sensors specifically developed by E2V (formerly Atmel) Grenoble SA as part of the European FP6 project – sensation (advanced sensor development for attention stress, vigilance and sleep/wakefulness monitoring).
Results : The developed system can sustain frame rates of 59.8 Hz at the full stereovision resolution of 1280 × 480 but this can reach 750 Hz when a 10 k pixel Region of Interest (ROI) is used, with a maximum global shutter speed of 1/48000 s and a shutter efficiency of 99.7%. The data can be reliably transmitted uncompressed over standard copper Camera-Link® cables over 5 metres. The synchronisation error between the left and right stereo images is less than 100 ps and this has been verified both electrically and optically. Synchronisation is automatically established at boot-up and maintained during resolution changes. A third camera in the set can be configured independently. The dynamic range of the 10bit sensors exceeds 123 dB with a spectral sensitivity extending well into the infra-red range.
Conclusion: The system was subjected to a comprehensive testing protocol, which confirms that the salient requirements for the driver monitoring application are adequately met and in some respects, exceeded. The synchronisation technique presented may also benefit several other automotive stereovision applications including near and far-field obstacle detection and collision avoidance, road condition monitoring and others.Partially funded by the EU FP6 through the IST-507231 SENSATION project.peer-reviewe
Requirements for DNA-bridging proteins to act as topological barriers of the bacterial genome
Bacterial genomes have been shown to be partitioned into several kilobases
long chromosomal domains that are topologically independent from each other,
meaning that change of DNA superhelicity in one domain does not propagate to
neighbors. Both in vivo and in vitro experiments have been performed to
question the nature of the topological barriers at play, leading to several
predictions on possible molecular actors. Here, we address the question of
topological barriers using polymer models of supercoiled DNA chains. More
specifically, we determine under which conditions DNA-bridging proteins may act
as topological barriers. To this end, we developed a coarse-grained
bead-and-spring model and investigated its properties through Brownian dynamics
simulations. As a result, we find that DNA-bridging proteins must exert rather
strong constraints on their binding sites: they must block the diffusion of the
excess of twist through the two binding sites on the DNA molecule and,
simultaneously, prevent the rotation of one DNA segment relative to the other
one. Importantly, not all DNA-bridging proteins satisfy this second condition.
For example, single bridges formed by proteins that bind DNA non-specifically,
like H-NS dimers, are expected to fail with this respect. Our findings might
also explain, in the case of specific DNA-bridging proteins like LacI, why
multiple bridges are required to create stable independent topological domains.
Strikingly, when the relative rotation of the DNA segments is not prevented,
relaxation results in complex intrication of the two domains. Moreover, while
the value of the torsional stress in each domain may vary, their differential
is preserved. Our work also predicts that nucleoid associated proteins known to
wrap DNA must form higher protein-DNA complexes to efficiently work as
topological barriers.Comment: Accepted for publication in the Biophysical Journa
Digital Deception: Generative Artificial Intelligence in Social Engineering and Phishing
The advancement of Artificial Intelligence (AI) and Machine Learning (ML) has
profound implications for both the utility and security of our digital
interactions. This paper investigates the transformative role of Generative AI
in Social Engineering (SE) attacks. We conduct a systematic review of social
engineering and AI capabilities and use a theory of social engineering to
identify three pillars where Generative AI amplifies the impact of SE attacks:
Realistic Content Creation, Advanced Targeting and Personalization, and
Automated Attack Infrastructure. We integrate these elements into a conceptual
model designed to investigate the complex nature of AI-driven SE attacks - the
Generative AI Social Engineering Framework. We further explore human
implications and potential countermeasures to mitigate these risks. Our study
aims to foster a deeper understanding of the risks, human implications, and
countermeasures associated with this emerging paradigm, thereby contributing to
a more secure and trustworthy human-computer interaction.Comment: Submitted to CHI 202
Occupational segregation in a Roy model with composition preferences
We propose a model of labor market sector self-selection that combines
comparative advantage, as in the Roy model, and sector composition preference.
Two groups choose between two sectors based on heterogeneous potential incomes
and group compositions in each sector. Potential incomes incorporate group
specific human capital accumulation and wage discrimination. Composition
preferences are interpreted as reflecting group specific amenity preferences as
well as homophily and aversion to minority status. We show that occupational
segregation is amplified by the composition preferences and we highlight a
resulting tension between redistribution and diversity. The model also exhibits
tipping from extreme compositions to more balanced ones. Tipping occurs when a
small nudge, associated with affirmative action, pushes the system to a very
different equilibrium, and when the set of equilibria changes abruptly when a
parameter governing the relative importance of pecuniary and composition
preferences crosses a threshold
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