1,498 research outputs found
Measuring Tie Strength in Implicit Social Networks
Given a set of people and a set of events they attend, we address the problem
of measuring connectedness or tie strength between each pair of persons given
that attendance at mutual events gives an implicit social network between
people. We take an axiomatic approach to this problem. Starting from a list of
axioms that a measure of tie strength must satisfy, we characterize functions
that satisfy all the axioms and show that there is a range of measures that
satisfy this characterization. A measure of tie strength induces a ranking on
the edges (and on the set of neighbors for every person). We show that for
applications where the ranking, and not the absolute value of the tie strength,
is the important thing about the measure, the axioms are equivalent to a
natural partial order. Also, to settle on a particular measure, we must make a
non-obvious decision about extending this partial order to a total order, and
that this decision is best left to particular applications. We classify
measures found in prior literature according to the axioms that they satisfy.
In our experiments, we measure tie strength and the coverage of our axioms in
several datasets. Also, for each dataset, we bound the maximum Kendall's Tau
divergence (which measures the number of pairwise disagreements between two
lists) between all measures that satisfy the axioms using the partial order.
This informs us if particular datasets are well behaved where we do not have to
worry about which measure to choose, or we have to be careful about the exact
choice of measure we make.Comment: 10 page
Poles in the -Matrix of Relativistic Chern-Simons Matter theories from Quantum Mechanics
An all orders formula for the -matrix for 2 2 scattering in
large N Chern-Simons theory coupled to a fundamental scalar has recently been
conjectured. We find a scaling limit of the theory in which the pole in this
-matrix is near threshold. We argue that the theory must be well described
by non-relativistic quantum mechanics in this limit, and determine the relevant
Schroedinger equation. We demonstrate that the -matrix obtained from this
Schroedinger equation agrees perfectly with this scaling limit of the
relativistic -matrix; in particular the pole structures match exactly. We
view this matching as a nontrivial consistency check of the conjectured field
theory -matrix.Comment: 12 pages, minor correction
Hunting For Metamorphic JavaScript Malware
Internet plays a major role in the propagation of malware. A recent trend is the infection of machines through web pages, often due to malicious code inserted in JavaScript. From the malware writer’s perspective, one potential advantage of JavaScript is that powerful code obfuscation techniques can be applied to evade de- tection. In this research, we analyze metamorphic JavaScript malware. We compare the effectiveness of several static detection strategies and we quantify the degree of morphing required to defeat each of these techniques
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