7,384 research outputs found
Phantom cascades: The effect of hidden nodes on information diffusion
Research on information diffusion generally assumes complete knowledge of the
underlying network. However, in the presence of factors such as increasing
privacy awareness, restrictions on application programming interfaces (APIs)
and sampling strategies, this assumption rarely holds in the real world which
in turn leads to an underestimation of the size of information cascades. In
this work we study the effect of hidden network structure on information
diffusion processes. We characterise information cascades through activation
paths traversing visible and hidden parts of the network. We quantify diffusion
estimation error while varying the amount of hidden structure in five empirical
and synthetic network datasets and demonstrate the effect of topological
properties on this error. Finally, we suggest practical recommendations for
practitioners and propose a model to predict the cascade size with minimal
information regarding the underlying network.Comment: Preprint submitted to Elsevier Computer Communication
Submodular Inference of Diffusion Networks from Multiple Trees
Diffusion and propagation of information, influence and diseases take place
over increasingly larger networks. We observe when a node copies information,
makes a decision or becomes infected but networks are often hidden or
unobserved. Since networks are highly dynamic, changing and growing rapidly, we
only observe a relatively small set of cascades before a network changes
significantly. Scalable network inference based on a small cascade set is then
necessary for understanding the rapidly evolving dynamics that govern
diffusion. In this article, we develop a scalable approximation algorithm with
provable near-optimal performance based on submodular maximization which
achieves a high accuracy in such scenario, solving an open problem first
introduced by Gomez-Rodriguez et al (2010). Experiments on synthetic and real
diffusion data show that our algorithm in practice achieves an optimal
trade-off between accuracy and running time.Comment: To appear in the 29th International Conference on Machine Learning
(ICML), 2012. Website:
http://www.stanford.edu/~manuelgr/network-inference-multitree
Muon-Induced Background Study for Underground Laboratories
We provide a comprehensive study of the cosmic-ray muon flux and induced
activity as a function of overburden along with a convenient parameterization
of the salient fluxes and differential distributions for a suite of underground
laboratories ranging in depth from 1 to 8 km.w.e.. Particular attention
is given to the muon-induced fast neutron activity for the underground sites
and we develop a Depth-Sensitivity-Relation to characterize the effect of such
background in experiments searching for WIMP dark matter and neutrinoless
double beta decay.Comment: 18 pages, 28 figure
Mathematics of complexity in experimental high energy physics
Mathematical ideas and approaches common in complexity-related fields have
been fruitfully applied in experimental high energy physics also. We briefly
review some of the cross-pollination that is occurring.Comment: 7 pages, 3 figs, latex; Second International Conference on Frontier
Science: A Nonlinear World: The Real World, Pavia, Italy, 8-12 September 200
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