28,246 research outputs found
Bayesian algorithms for recovering structure from single-particle diffraction snapshots of unknown orientation: a comparison
The advent of X-ray Free Electron Lasers promises the possibility to
determine the structure of individual particles such as microcrystallites,
viruses and biomolecules from single-shot diffraction snapshots obtained before
the particle is destroyed by the intense femtosecond pulse. This program
requires the ability to determine the orientation of the particle giving rise
to each snapshot at signal levels as low as ~10-2 photons/pixel. Two apparently
different approaches have recently demonstrated this capability. Here we show
they represent different implementations of the same fundamental approach, and
identify the primary factors limiting their performance.Comment: 10 pages, 2 figure
Hierarchical structuring of Cultural Heritage objects within large aggregations
Huge amounts of cultural content have been digitised and are available
through digital libraries and aggregators like Europeana.eu. However, it is not
easy for a user to have an overall picture of what is available nor to find
related objects. We propose a method for hier- archically structuring cultural
objects at different similarity levels. We describe a fast, scalable clustering
algorithm with an automated field selection method for finding semantic
clusters. We report a qualitative evaluation on the cluster categories based on
records from the UK and a quantitative one on the results from the complete
Europeana dataset.Comment: The paper has been published in the proceedings of the TPDL
conference, see http://tpdl2013.info. For the final version see
http://link.springer.com/chapter/10.1007%2F978-3-642-40501-3_2
Indexing, browsing and searching of digital video
Video is a communications medium that normally brings together moving pictures with a synchronised audio track into a discrete piece or pieces of information. The size of a “piece ” of video can variously be referred to as a frame, a shot, a scene, a clip, a programme or an episode, and these are distinguished by their lengths and by their composition. We shall return to the definition of each of these in section 4 this chapter. In modern society, video is ver
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