6,590 research outputs found
Shaping electron beams for the generation of innovative measurements in the (S)TEM
In TEM, a typical goal consists of making a small electron probe in the
sample plane in order to obtain high spatial resolution in scanning
transmission electron microscopy. In order to do so, the phase of the electron
wave is corrected to resemble a spherical wave compensating for aberrations in
the magnetic lenses. In this contribution we discuss the advantage of changing
the phase of an electron wave in a specific way in order to obtain
fundamentally different electron probes opening up new application in the
(S)TEM. We focus on electron vortex states as a specific family of waves with
an azimuthal phase signature and discuss their properties, production and
applications. The concepts presented here are rather general and also different
classes of probes can be obtained in a similar fashion showing that electron
probes can be tuned to optimise a specific measurement or interaction
BullStop: A Mobile App for Cyberbullying Prevention
Social media has become the new playground for bullies. Young people are now regularly exposed to a wide range of abuse online. In response to the increasing prevalence of cyberbullying, online social networks have increased efforts to clamp down on online abuse but unfortunately, the nature, complexity and sheer volume of cyberbullying means that many cyberbullying incidents go undetected. BullStop is a mobile app for detecting and preventing cyberbullying and online abuse on social media platforms. It uses deep learning models to identify instances of cyberbullying and can automatically initiate actions such as deleting offensive messages and blocking bullies on behalf of the user. Our system not only achieves impressive prediction results but also demonstrates excellent potential for use in real-world scenarios and is freely available on the Google Play Store
High-Precision Extraction of Emerging Concepts from Scientific Literature
Identification of new concepts in scientific literature can help power
faceted search, scientific trend analysis, knowledge-base construction, and
more, but current methods are lacking. Manual identification cannot keep up
with the torrent of new publications, while the precision of existing automatic
techniques is too low for many applications. We present an unsupervised concept
extraction method for scientific literature that achieves much higher precision
than previous work. Our approach relies on a simple but novel intuition: each
scientific concept is likely to be introduced or popularized by a single paper
that is disproportionately cited by subsequent papers mentioning the concept.
From a corpus of computer science papers on arXiv, we find that our method
achieves a Precision@1000 of 99%, compared to 86% for prior work, and a
substantially better precision-yield trade-off across the top 15,000
extractions. To stimulate research in this area, we release our code and data
(https://github.com/allenai/ForeCite).Comment: Accepted to SIGIR 202
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