14,984 research outputs found
Applying modern portfolio theory to the analysis of terrorism: computing the set of attack method combinations from which the rational terrorist group will choose in order to maximise injuries and fatalities
In this paper, terrorism is analysed using the tools of modern portfolio theory. This approach permits the analysis of the returns that a terrorist group can expect from their activities as well as the risk they face. The analysis sheds new light on the nature of the terrorist group’s (attack method) choice set and the efficiency properties of that set. If terrorist groups are, on average, more risk averse, the economist can expect the terrorist group to exhibit a bias towards bombing and armed attack. In addition, even the riskiest (from the terrorist group’s point of view) combinations of
attack methods have maximum expected returns of less than 70 injuries and fatalities per attack per year
Proposed cavity Josephson plasmonics with complex-oxide heterostructures
We discuss how complex-oxide heterostructures that include high-Tc
superconducting cuprates can be used to realize an array of sub-millimeter
cavities that support Josephson plasmon polaritons. These cavities have several
attractive features for new types of light matter interaction studies and we
show that they promote "ultrastrong" coupling between THz frequency radiation
and Josephson plasmons. Cavity electrodynamics of Josephson plasmons allows to
manipulate the superconducting order-parameter phase coherence. As an example,
we discuss how it could be used to cool superconducting phase fluctuations with
light
Computational Modalities of Belousov-Zhabotinsky Encapsulated Vesicles
We present both simulated and partial empirical evidence for the
computational utility of many connected vesicle analogs of an encapsulated
non-linear chemical processing medium. By connecting small vesicles containing
a solution of sub-excitable Belousov-Zhabotinsky (BZ) reaction, sustained and
propagating wave fragments are modulated by both spatial geometry, network
connectivity and their interaction with other waves. The processing ability is
demonstrated through the creation of simple Boolean logic gates and then by the
combination of those gates to create more complex circuits
Vacancies, disorder-induced smearing of the electronic structure, and its implications for the superconductivity of anti-perovskite MgCNi
The anti-perovskite superconductor MgCNi was studied using
high-resolution x-ray Compton scattering combined with electronic structure
calculations. Compton scattering measurements were used to determine
experimentally a Fermi surface that showed good agreement with that of our
supercell calculations, establishing the presence of the predicted hole and
electron Fermi surface sheets. Our calculations indicate that the Fermi surface
is smeared by the disorder due to the presence of vacancies on the C and Ni
sites, but does not drastically change shape. The 20\% reduction in the Fermi
level density-of-states would lead to a significant () suppression
of the superconducting for pair-forming electron-phonon coupling.
However, we ascribe the observed much smaller reduction at our
composition (compared to the stoichiometric compound) to the suppression of
pair-breaking spin fluctuations.Comment: 11 pages, 3 figure
A Survey on Continuous Time Computations
We provide an overview of theories of continuous time computation. These
theories allow us to understand both the hardness of questions related to
continuous time dynamical systems and the computational power of continuous
time analog models. We survey the existing models, summarizing results, and
point to relevant references in the literature
Excitable Delaunay triangulations
In an excitable Delaunay triangulation every node takes three states
(resting, excited and refractory) and updates its state in discrete time
depending on a ratio of excited neighbours. All nodes update their states in
parallel. By varying excitability of nodes we produce a range of phenomena,
including reflection of excitation wave from edge of triangulation, backfire of
excitation, branching clusters of excitation and localized excitation domains.
Our findings contribute to studies of propagating perturbations and waves in
non-crystalline substrates
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