2,999 research outputs found
Texture to the Rescue : Practical Paper Fingerprinting based on Texture Patterns
In this article, we propose a novel paper fingerprinting technique based on analyzing the translucent patterns revealed when a light source shines through the paper. These patterns represent the inherent texture of paper, formed by the random interleaving of wooden particles during the manufacturing process. We show that these patterns can be easily captured by a commodity camera and condensed into a compact 2,048-bit fingerprint code. Prominent works in this area (Nature 2005, IEEE S&P 2009, CCS 2011) have all focused on fingerprinting paper based on the paper "surface." We are motivated by the observation that capturing the surface alone misses important distinctive features such as the noneven thickness, random distribution of impurities, and different materials in the paper with varying opacities. Through experiments, we demonstrate that the embedded paper texture provides a more reliable source for fingerprinting than features on the surface. Based on the collected datasets, we achieve 0% false rejection and 0% false acceptance rates. We further report that our extracted fingerprints contain 807 degrees of freedom (DoF), which is much higher than the 249 DoF with iris codes (that have the same size of 2,048 bits). The high amount of DoF for texturebased fingerprints makes our method extremely scalable for recognition among very large databases; it also allows secure usage of the extracted fingerprint in privacy-preserving authentication schemes based on error correction techniques
Recognizing the fingerprints of the Galactic bar: a quantitative approach to comparing model (l,v) distributions to observation
We present a new method for fitting simple hydrodynamical models to the (l,v)
distribution of atomic and molecular gas observed in the Milky Way. The method
works by matching features found in models and observations. It is based on the
assumption that the large-scale features seen in (l,v) plots, such as
ridgelines and the terminal velocity curve, are influenced primarily by the
underlying large-scale Galactic potential and are only weakly dependent on
local ISM heating and cooling processes. In our scheme one first identifies by
hand the features in the observations: this only has to be done once. We
describe a procedure for automatically extracting similar features from simple
hydrodynamical models and quantifying the "distance" between each model's
features and the observations. Application to models of the Galactic Bar region
(|l|<30deg) shows that our feature-fitting method performs better than \chi^2
or envelope distances at identifying the correct underlying galaxy model.Comment: Accepted for publication in MNRA
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Magnetic resonance multitasking for motion-resolved quantitative cardiovascular imaging.
Quantitative cardiovascular magnetic resonance (CMR) imaging can be used to characterize fibrosis, oedema, ischaemia, inflammation and other disease conditions. However, the need to reduce artefacts arising from body motion through a combination of electrocardiography (ECG) control, respiration control, and contrast-weighting selection makes CMR exams lengthy. Here, we show that physiological motions and other dynamic processes can be conceptualized as multiple time dimensions that can be resolved via low-rank tensor imaging, allowing for motion-resolved quantitative imaging with up to four time dimensions. This continuous-acquisition approach, which we name cardiovascular MR multitasking, captures - rather than avoids - motion, relaxation and other dynamics to efficiently perform quantitative CMR without the use of ECG triggering or breath holds. We demonstrate that CMR multitasking allows for T1 mapping, T1-T2 mapping and time-resolved T1 mapping of myocardial perfusion without ECG information and/or in free-breathing conditions. CMR multitasking may provide a foundation for the development of setup-free CMR imaging for the quantitative evaluation of cardiovascular health
Optimizing MRFâ ASL scan design for precise quantification of brain hemodynamics using neural network regression
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154517/1/mrm28051.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154517/2/mrm28051_am.pd
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Republican Monsters: The Cultural Construction of American Positivist Criminology, 1767-1920
This dissertation examines the history of and cultural influences on positivist criminology in the United States. From Benjamin Rush to the present day, the U.S. has produced an extensive corpus of empirical and theoretical studies that seeks to discern an objective, scientifically-grounded basis for criminal behavior. American positivist criminology has drawn on numerous subfields and theories, including rational choice / economic theory, biology, and psychology, but in all cases, maintains that a purely scientific explanation of offending is possible. This study proceeds from the perspective that divisions between scientific and non-scientific thought are untenable. Drawing on scholarship in literary criticism and sociology, I argue that positivist criminology confronts an inherent contradiction in purporting to develop a purely scientific account of phenomena that are defined by the moral and cultural sentiments of a society. I thus hypothesize that positivist criminology is in fact reliant on the irrational and fictive cultural tropes and images of crime that it claims to exorcize. The dissertation proceeds by reviewing the literature on the history of criminology, developing a set of functional types or tropes for character analysis, and then examining four separate periods in the development of scientific criminology: eighteenth century studies of rational action, nineteenth century studies of defective reasoning, early twentieth century studies of race and crime, and the development of scientifically informed criminalistics programs. Each of these cases captures a different period and focus in the development of scientific criminology. In threading continuity between these cases, I show how criminological positivism is consistently reliant on culturally informed tropes and characters to render itself sensible and coherent
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