4,969 research outputs found
Towards a Quantum-Like Cognitive Architecture for Decision-Making
We propose an alternative and unifying framework for decision-making that, by
using quantum mechanics, provides more generalised cognitive and decision
models with the ability to represent more information than classical models.
This framework can accommodate and predict several cognitive biases reported in
Lieder & Griffiths without heavy reliance on heuristics nor on assumptions of
the computational resources of the mind
The Brownfields Phenomenon: Much Ado about Something or the Timing of the Shrewd?
This paper provides an overview of the cleanup and redevelopment of contaminated properties known as “brownfields.” It has three principal parts. First, we introduce the brownfields phenomenon and its drivers, drawing on the body of available empirical evidence to discuss characteristics of individual brownfield redevelopment projects. Second, we present findings from a recent study we have conducted that examines the relative attractiveness to private developers of public interventions to promote brownfields redevelopment. Third, we briefly summarize some of the problems with brownfields development and policy and propose an approach to promote wider societal benefits of brownfields development. We conclude with several broad questions about brownfields policy and practice.brownfields, contamination, economic development, infill
Gravitational waves from fermion production during axion inflation
We present analytic results for the gravitational wave power spectrum induced
in models where the inflaton is coupled to a fermionic pseudocurrent. We show
that although such a coupling creates helically polarized fermions, the
polarized component of the resulting gravitational waves is parametrically
suppressed with respect to the non-polarized one. We also show that the
amplitude of the gravitational wave signal associated to this production cannot
exceed that generated by the standard mechanism of amplification of vacuum
fluctuations. We previously found that this model allows for a regime in which
the backreaction of the produced fermions allows for slow-roll inflation even
for a steep inflaton potential, and still leads to Gaussian primordial scalar
perturbations. The present analysis shows that this regime also results in a
gravitational wave signal compatible with the current bounds.Comment: 29 pages, 2 figure
Hypersparse Neural Network Analysis of Large-Scale Internet Traffic
The Internet is transforming our society, necessitating a quantitative
understanding of Internet traffic. Our team collects and curates the largest
publicly available Internet traffic data containing 50 billion packets.
Utilizing a novel hypersparse neural network analysis of "video" streams of
this traffic using 10,000 processors in the MIT SuperCloud reveals a new
phenomena: the importance of otherwise unseen leaf nodes and isolated links in
Internet traffic. Our neural network approach further shows that a
two-parameter modified Zipf-Mandelbrot distribution accurately describes a wide
variety of source/destination statistics on moving sample windows ranging from
100,000 to 100,000,000 packets over collections that span years and continents.
The inferred model parameters distinguish different network streams and the
model leaf parameter strongly correlates with the fraction of the traffic in
different underlying network topologies. The hypersparse neural network
pipeline is highly adaptable and different network statistics and training
models can be incorporated with simple changes to the image filter functions.Comment: 11 pages, 10 figures, 3 tables, 60 citations; to appear in IEEE High
Performance Extreme Computing (HPEC) 201
Understanding the Structural Scaling Relations of Early-Type Galaxies
We use a large suite of hydrodynamical simulations of binary galaxy mergers
to construct and calibrate a physical prescription for computing the effective
radii and velocity dispersions of spheroids. We implement this prescription
within a semi-analytic model embedded in merger trees extracted from the
Bolshoi Lambda-CDM N-body simulation, accounting for spheroid growth via major
and minor mergers as well as disk instabilities. We find that without disk
instabilities, our model does not predict sufficient numbers of intermediate
mass early-type galaxies in the local universe. Spheroids also form earlier in
models with spheroid growth via disk instabilities. Our model correctly
predicts the normalization, slope, and scatter of the low-redshift size-mass
and Fundamental Plane relations for early type galaxies. It predicts a degree
of curvature in the Faber-Jackson relation that is not seen in local
observations, but this could be alleviated if higher mass spheroids have more
bottom-heavy initial mass functions. The model also correctly predicts the
observed strong evolution of the size-mass relation for spheroids out to higher
redshifts, as well as the slower evolution in the normalization of the
Faber-Jackson relation. We emphasize that these are genuine predictions of the
model since it was tuned to match hydrodynamical simulations and not these
observations.Comment: Submitted to MNRA
Relation between Brown Dwarfs and Exoplanets
One of the most debated subjects in Astronomy since the discovery of
exoplanets is how can we distinguish the most massive of such objects from
very-low mass stars like Brown Dwarfs (BDs)? We have been looking for evidences
of a difference in physical characteristics that could be related to different
formation processes. Using a new diagnostic diagram that compares the baryonic
gravitational potential (BGP) with the distances from their host stars, we have
classified a sample of 355 well-studied exoplanets according to their possible
structures. We have then compared the exoplanets to a sample of 87 confirmed
BDs, identifying a range in BGP that could be common to both objects. By
analyzing the mass-radius relations (MRR) of the exoplanets and BDs in those
different BGP ranges, we were able to distinguish different characteristic
behaviors. By comparing with models in the literature, our results suggest that
BDs and massive exoplanets might have similar structures dominated by liquid
metallic hydrogen (LMH).Comment: Poster #149 from proceeding of The 19th Cambridge Workshop on Cool
Stars, Stellar Systems, and the Sun; 06-10 June 2016, Uppsala, Swede
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