2,305 research outputs found
On symmetric continuum opinion dynamics
This paper investigates the asymptotic behavior of some common opinion
dynamic models in a continuum of agents. We show that as long as the
interactions among the agents are symmetric, the distribution of the agents'
opinion converges. We also investigate whether convergence occurs in a stronger
sense than merely in distribution, namely, whether the opinion of almost every
agent converges. We show that while this is not the case in general, it becomes
true under plausible assumptions on inter-agent interactions, namely that
agents with similar opinions exert a non-negligible pull on each other, or that
the interactions are entirely determined by their opinions via a smooth
function.Comment: 28 pages, 2 figures, 3 file
Privacy-Friendly Collaboration for Cyber Threat Mitigation
Sharing of security data across organizational boundaries has often been
advocated as a promising way to enhance cyber threat mitigation. However,
collaborative security faces a number of important challenges, including
privacy, trust, and liability concerns with the potential disclosure of
sensitive data. In this paper, we focus on data sharing for predictive
blacklisting, i.e., forecasting attack sources based on past attack
information. We propose a novel privacy-enhanced data sharing approach in which
organizations estimate collaboration benefits without disclosing their
datasets, organize into coalitions of allied organizations, and securely share
data within these coalitions. We study how different partner selection
strategies affect prediction accuracy by experimenting on a real-world dataset
of 2 billion IP addresses and observe up to a 105% prediction improvement.Comment: This paper has been withdrawn as it has been superseded by
arXiv:1502.0533
Distributed anonymous function computation in information fusion and multiagent systems
We propose a model for deterministic distributed function computation by a
network of identical and anonymous nodes, with bounded computation and storage
capabilities that do not scale with the network size. Our goal is to
characterize the class of functions that can be computed within this model. In
our main result, we exhibit a class of non-computable functions, and prove that
every function outside this class can at least be approximated. The problem of
computing averages in a distributed manner plays a central role in our
development
Distributed anonymous discrete function computation
We propose a model for deterministic distributed function computation by a
network of identical and anonymous nodes. In this model, each node has bounded
computation and storage capabilities that do not grow with the network size.
Furthermore, each node only knows its neighbors, not the entire graph. Our goal
is to characterize the class of functions that can be computed within this
model. In our main result, we provide a necessary condition for computability
which we show to be nearly sufficient, in the sense that every function that
satisfies this condition can at least be approximated. The problem of computing
suitably rounded averages in a distributed manner plays a central role in our
development; we provide an algorithm that solves it in time that grows
quadratically with the size of the network
Matrix P-norms are NP-hard to approximate if p \neq 1,2,\infty
We show that for any rational p \in [1,\infty) except p = 1, 2, unless P =
NP, there is no polynomial-time algorithm for approximating the matrix p-norm
to arbitrary relative precision. We also show that for any rational p\in
[1,\infty) including p = 1, 2, unless P = NP, there is no polynomial-time
algorithm approximates the \infty, p mixed norm to some fixed relative
precision.Comment: 12 page
Origin of band gaps in 3d perovskite oxides
With their broad range of magnetic, electronic and structural properties,
transition metal perovskite oxides ABO3 have long served as a platform for
testing condensed matter theories. In particular, their insulating character -
found in most compounds - is often ascribed to dynamical electronic
correlations through the celebrated Mott-Hubbard mechanism where gaping arises
from a uniform, symmetry-preserving electron repulsion mechanism. However,
structural distortions are ubiquitous in perovskites and their relevance with
respect to dynamical correlations in producing this rich array of properties
remains an open question. Here, we address the origin of band gap opening in
the whole family of 3d perovskite oxides. We show that a single-determinant
mean-field approach such as density functional theory (DFT) successfully
describes the structural, magnetic and electronic properties of the whole
series, at low and high temperatures. We find that insulation occurs via
energy-lowering crystal symmetry reduction (octahedral rotations, Jahn-Teller
and bond disproportionation effects), as well as intrinsic electronic
instabilities, all lifting orbital degeneracies. Our work therefore suggests
that whereas ABO3 oxides may be complicated, they are not necessarily strongly
correlated. It also opens the way towards systematic investigations of doping
and defect physics in perovskites, essential for the full realization of
oxide-based electronics
Mott gapping in 3d ABO3 perovskites without Mott-Hubbard interelectronic U
The existence of band gaps in Mott insulators such as perovskite oxides with
partially filled 3d shells has been traditionally explained in terms of strong,
dynamic inter-electronic repulsion codified by the on-site repulsion energy U
in the Hubbard Hamiltonian. The success of the "DFT+U approach" where an
empirical on-site potential term U is added to the exchange-and correlation
Density Functional Theory (DFT) raised questions on whether U in DFT+U
represents interelectronic correlation in the same way as it does in the
Hubbard Hamiltonian, and if empiricism in selecting U can be avoided. Here we
illustrate that ab-initio DFT without any U is able to predict gapping trends
and structural symmetry breaking (octahedra rotations, Jahn-Teller modes, bond
disproportionation) for all ABO3 3d perovskites from titanates to nickelates in
both spin-ordered and spin disordered paramagnetic phases. We describe the
paramagnetic phases as a supercell where individual sites can have different
local environments thereby allowing DFT to develop finite moments on different
sites as long as the total cell has zero moment. We use a recently developed
exchange and correlation functional ("SCAN") that is sanctioned by the usual
single-determinant, mean-field DFT paradigm with static correlations, but has a
more precise rendering of self-interaction cancelation. Our results suggest
that strong dynamic electronic correlations are not playing a universal role in
gapping of 3d ABO3 Mott insulators, and opens the way for future applications
of DFT for studying a plethora of complexity effects that depend on the
existence of gaps, such as doping, defects, and band alignment in ABO3 oxides
Opioid Abuse as a Result of Work Related Trauma
Our studies examine and observe the widespread impact that prescription opioids have left on the United States, with a specific focus on working-class Americans and veterans. By narrowing our reach to Americans who are forced to handle large amounts of physical labor we have found a strong correlation between these workers getting injured on the job and opioid abuse. Finding that the it is generally attributed to overprescription and unnecessary prescription from physicians. The information was drawn from studies, surveys, dissertations and censuses. Observing these works on injuries/trauma caused by these occupations has yielded important information to the origin of this epidemic. These works can lead to understanding the problems associated with this correlation and further look for potential fixes that can be implemented. Although the number of prescriptions has lowered in recent years the number of prescriptions is still far too high to warrant neglecting this topic.https://orb.binghamton.edu/research_days_posters_spring2020/1086/thumbnail.jp
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