692 research outputs found
Proceed with caution: on the use of computational linguistics in threat assessment
Large-scale linguistic analyses are increasingly applied to the study of extremism, terrorism, and other threats of violence. At the same time, practitioners working in the field of counterterrorism and security are confronted with large-scale linguistic data, and may benefit from computational methods. This article highlights the challenges and opportunities associated with applying computational linguistics in the domain of threat assessment. Four current issues are identified, namely (1) the data problem, (2) the utopia of predicting violence, (3) the base rate fallacy, and (4) the danger of closed-sourced tools. These challenges are translated into a checklist of questions that should be asked by policymakers and practitioners who (intend to) make use of tools that leverage computational linguistics for threat assessment. The ‘VISOR-P’ checklist can be used to evaluate such tools through their Validity, Indicators, Scientific Quality, Openness, Relevance and Performance. Finally, some suggestions are outlined for the furtherance of the computational linguistic threat assessment field
Proceed with caution:On the use of computational linguistics in threat assessment
Large-scale linguistic analyses are increasingly applied to the study of extremism, terrorism, and other threats of violence. At the same time, practitioners working in the field of counterterrorism and security are confronted with large-scale linguistic data, and may benefit from computational methods. This article highlights the challenges and opportunities associated with applying computational linguistics in the domain of threat assessment. Four current issues are identified, namely (1) the data problem, (2) the utopia of predicting violence, (3) the base rate fallacy, and (4) the danger of closed-sourced tools. These challenges are translated into a checklist of questions that should be asked by policymakers and practitioners who (intend to) make use of tools that leverage computational linguistics for threat assessment. The ‘VISOR-P’ checklist can be used to evaluate such tools through their Validity, Indicators, Scientific Quality, Openness, Relevance and Performance. Finally, some suggestions are outlined for the furtherance of the computational linguistic threat assessment field.</p
Merlin: A Language for Provisioning Network Resources
This paper presents Merlin, a new framework for managing resources in
software-defined networks. With Merlin, administrators express high-level
policies using programs in a declarative language. The language includes
logical predicates to identify sets of packets, regular expressions to encode
forwarding paths, and arithmetic formulas to specify bandwidth constraints. The
Merlin compiler uses a combination of advanced techniques to translate these
policies into code that can be executed on network elements including a
constraint solver that allocates bandwidth using parameterizable heuristics. To
facilitate dynamic adaptation, Merlin provides mechanisms for delegating
control of sub-policies and for verifying that modifications made to
sub-policies do not violate global constraints. Experiments demonstrate the
expressiveness and scalability of Merlin on real-world topologies and
applications. Overall, Merlin simplifies network administration by providing
high-level abstractions for specifying network policies and scalable
infrastructure for enforcing them
Connectivity strategies to enhance the capacity of weight-bearing networks
The connectivity properties of a weight-bearing network are exploited to
enhance it's capacity. We study a 2-d network of sites where the weight-bearing
capacity of a given site depends on the capacities of the sites connected to it
in the layers above. The network consists of clusters viz. a set of sites
connected with each other with the largest such collection of sites being
denoted as the maximal cluster. New connections are made between sites in
successive layers using two distinct strategies. The key element of our
strategies consists of adding as many disjoint clusters as possible to the
sites on the trunk of the maximal cluster. The new networks can bear much
higher weights than the original networks and have much lower failure rates.
The first strategy leads to a greater enhancement of stability whereas the
second leads to a greater enhancement of capacity compared to the original
networks. The original network used here is a typical example of the branching
hierarchical class. However the application of strategies similar to ours can
yield useful results in other types of networks as well.Comment: 17 pages, 3 EPS files, 5 PS files, Phys. Rev. E (to appear
Shedding Light on Terrorist and Extremist Content Removal
Social media and tech companies face the challenge of identifying and
removing terrorist and extremist content from their platforms. This paper
presents the findings of a series of interviews with Global Internet Forum
to Counter Terrorism (GIFCT) partner companies and law enforcement
Internet Referral Units (IRUs). It offers a unique view on current practices
and challenges regarding content removal, focusing particularly on
human-based and automated approaches and the integration of the two
The Cavity Approach to Parallel Dynamics of Ising Spins on a Graph
We use the cavity method to study parallel dynamics of disordered Ising
models on a graph. In particular, we derive a set of recursive equations in
single site probabilities of paths propagating along the edges of the graph.
These equations are analogous to the cavity equations for equilibrium models
and are exact on a tree. On graphs with exclusively directed edges we find an
exact expression for the stationary distribution of the spins. We present the
phase diagrams for an Ising model on an asymmetric Bethe lattice and for a
neural network with Hebbian interactions on an asymmetric scale-free graph. For
graphs with a nonzero fraction of symmetric edges the equations can be solved
for a finite number of time steps. Theoretical predictions are confirmed by
simulation results. Using a heuristic method, the cavity equations are extended
to a set of equations that determine the marginals of the stationary
distribution of Ising models on graphs with a nonzero fraction of symmetric
edges. The results of this method are discussed and compared with simulations
Quasistatic Scale-free Networks
A network is formed using the sites of an one-dimensional lattice in the
shape of a ring as nodes and each node with the initial degree .
links are then introduced to this network, each link starts from a distinct
node, the other end being connected to any other node with degree randomly
selected with an attachment probability proportional to . Tuning
the control parameter we observe a transition where the average degree
of the largest node changes its variation from to
at a specific transition point of . The network is scale-free i.e.,
the nodal degree distribution has a power law decay for .Comment: 4 pages, 5 figure
On the Mixing of Diffusing Particles
We study how the order of N independent random walks in one dimension evolves
with time. Our focus is statistical properties of the inversion number m,
defined as the number of pairs that are out of sort with respect to the initial
configuration. In the steady-state, the distribution of the inversion number is
Gaussian with the average ~N^2/4 and the standard deviation sigma N^{3/2}/6.
The survival probability, S_m(t), which measures the likelihood that the
inversion number remains below m until time t, decays algebraically in the
long-time limit, S_m t^{-beta_m}. Interestingly, there is a spectrum of
N(N-1)/2 distinct exponents beta_m(N). We also find that the kinetics of
first-passage in a circular cone provides a good approximation for these
exponents. When N is large, the first-passage exponents are a universal
function of a single scaling variable, beta_m(N)--> beta(z) with
z=(m-)/sigma. In the cone approximation, the scaling function is a root of a
transcendental equation involving the parabolic cylinder equation, D_{2
beta}(-z)=0, and surprisingly, numerical simulations show this prediction to be
exact.Comment: 9 pages, 6 figures, 2 table
The Mathematical Relationship between Zipf's Law and the Hierarchical Scaling Law
The empirical studies of city-size distribution show that Zipf's law and the
hierarchical scaling law are linked in many ways. The rank-size scaling and
hierarchical scaling seem to be two different sides of the same coin, but their
relationship has never been revealed by strict mathematical proof. In this
paper, the Zipf's distribution of cities is abstracted as a q-sequence. Based
on this sequence, a self-similar hierarchy consisting of many levels is defined
and the numbers of cities in different levels form a geometric sequence. An
exponential distribution of the average size of cities is derived from the
hierarchy. Thus we have two exponential functions, from which follows a
hierarchical scaling equation. The results can be statistically verified by
simple mathematical experiments and observational data of cities. A theoretical
foundation is then laid for the conversion from Zipf's law to the hierarchical
scaling law, and the latter can show more information about city development
than the former. Moreover, the self-similar hierarchy provides a new
perspective for studying networks of cities as complex systems. A series of
mathematical rules applied to cities such as the allometric growth law, the 2^n
principle and Pareto's law can be associated with one another by the
hierarchical organization.Comment: 30 pages, 5 figures, 5 tables, Physica A: Statistical Mechanics and
its Applications, 201
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