3,365 research outputs found
Challenges of Multi-Factor Authentication for Securing Advanced IoT (A-IoT) Applications
The unprecedented proliferation of smart devices together with novel
communication, computing, and control technologies have paved the way for the
Advanced Internet of Things~(A-IoT). This development involves new categories
of capable devices, such as high-end wearables, smart vehicles, and consumer
drones aiming to enable efficient and collaborative utilization within the
Smart City paradigm. While massive deployments of these objects may enrich
people's lives, unauthorized access to the said equipment is potentially
dangerous. Hence, highly-secure human authentication mechanisms have to be
designed. At the same time, human beings desire comfortable interaction with
their owned devices on a daily basis, thus demanding the authentication
procedures to be seamless and user-friendly, mindful of the contemporary urban
dynamics. In response to these unique challenges, this work advocates for the
adoption of multi-factor authentication for A-IoT, such that multiple
heterogeneous methods - both well-established and emerging - are combined
intelligently to grant or deny access reliably. We thus discuss the pros and
cons of various solutions as well as introduce tools to combine the
authentication factors, with an emphasis on challenging Smart City
environments. We finally outline the open questions to shape future research
efforts in this emerging field.Comment: 7 pages, 4 figures, 2 tables. The work has been accepted for
publication in IEEE Network, 2019. Copyright may be transferred without
notice, after which this version may no longer be accessibl
Towards all-dielectric metamaterials and nanophotonics
We review a new, rapidly developing field of all-dielectric nanophotonics
which allows to control both magnetic and electric response of structured
matter by engineering the Mie resonances in high-index dielectric
nanoparticles. We discuss optical properties of such dielectric nanoparticles,
methods of their fabrication, and also recent advances in all-dielectric
metadevices including couple-resonator dielectric waveguides, nanoantennas, and
metasurfaces
Categories of Emotion names in Web retrieved texts
The categorization of emotion names, i.e., the grouping of emotion words that
have similar emotional connotations together, is a key tool of Social
Psychology used to explore people's knowledge about emotions. Without
exception, the studies following that research line were based on the gauging
of the perceived similarity between emotion names by the participants of the
experiments. Here we propose and examine a new approach to study the categories
of emotion names - the similarities between target emotion names are obtained
by comparing the contexts in which they appear in texts retrieved from the
World Wide Web. This comparison does not account for any explicit semantic
information; it simply counts the number of common words or lexical items used
in the contexts. This procedure allows us to write the entries of the
similarity matrix as dot products in a linear vector space of contexts. The
properties of this matrix were then explored using Multidimensional Scaling
Analysis and Hierarchical Clustering. Our main findings, namely, the underlying
dimension of the emotion space and the categories of emotion names, were
consistent with those based on people's judgments of emotion names
similarities
Tris(tetrabutylammonium) hexakis(tert-butanethiolato-κS)hepta-μ3-chlorido-μ3-sulfido-hexamolybdate dihydrate
The octahedral cluster core of the anion in the structure of the title compound, (C16H36N)3[Mo6(C4H9S)6(μ3-Cl)7(μ3-S)]·2H2O, has -3 site symmetry. Two μ3-Cl atoms fully occupy positions in the cluster core, while the remaining six positions are statistically occupied by Cl and S atoms in a 1:5 ratio. The fully occupied Cl-atom positions are located on sites with 3 symmetry, and the N atom of tetrabutylammonium cation is located on a site with 2 symmetry. The structure contains also two disordered solvent water molecules, one of which is located on a threefold rotation axis and the other in a general position, both with an occupancy of 0.25. The water molecules are localized in cavities formed by the tetrabutylammonium cations and the tert-butanethiolate groups. The metal clusters are stacked in a cubic close packing arrangement along [001]
The volume of causal diamonds, asymptotically de Sitter space-times and irreversibility
In this note we prove that the volume of a causal diamond associated with an
inertial observer in asymptotically de Sitter 4-dimensional space-time is
monotonically increasing function of cosmological time. The asymptotic value of
the volume is that of in maximally symmetric de Sitter space-time. The
monotonic property of the volume is checked in two cases: in vacuum and in the
presence of a massless scalar field. In vacuum, the volume flow (with respect
to cosmological time) asymptotically vanishes if and only if future space-like
infinity is 3-manifold of constant curvature. The volume flow thus represents
irreversibility of asymptotic evolution in spacetimes with positive
cosmological constant.Comment: 15 pages, no figures; v.2: conjecture 1 on p. 11 made more precise;
version published in jhe
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