589 research outputs found
Investigation of the concept of beauty via a lock-in feedback experiment
Lock-in feedback circuits are routinely used in physics laboratories all
around the world to extract small signals out of a noisy environment. In a
recent paper (M. Kaptein, R. van Emden, and D. Iannuzzi, paper under review),
we have shown that one can adapt the algorithm exploited in those circuits to
gain insight in behavioral economics. In this paper, we extend this concept to
a very subjective socio-philosophical concept: the concept of beauty. We run an
experiment on 7414 volunteers, asking them to express their opinion on the
physical features of an avatar. Each participant was prompted with an image
whose features were adjusted sequentially via a lock-in feedback algorithm
driven by the opinion expressed by the previous participants. Our results show
that the method allows one to identify the most attractive features of the
avatar
Analysis of the mechanical behaviour of a 11.5 T Nb3Sn LHC dipole magnet according to the ring collar concept
According to the CERN-LHC (Large Hadron Collider) reference design, 10-tesla twin-aperture NbTi dipoles will be built with split collars that enclose both apertures. As part of the development program towards an experimental 11.5-tesla Nb3Sn LHC dipole magnet, the mechanical implications of an alternative collar concept have been studied with a finite element analysis. In this concept ring shaped collars are shrunk on each finished single aperture coil, thus providing the necessary room-temperature prestress. This system results in a major improvement of the stress distribution in the collars. It is noted that introduction of friction at the sliding planes can cause reopening of the gap between the yoke halves during excitation. This depends strongly on the value of the friction coefficient
Development of an experimental 10 T Nb3Sn dipole magnet for the CERN LHC
An experimental 1-m long twill aperture dipole magnet developed using a high-current Nb3Sn conductor in order to attain a magnetic field well beyond 10 T at 4.2 K is described. The emphasis in this Nb3Sn project is on the highest possible field within the known Large Hadron Collider (LHC) twin-aperture configuration. A design target of 11.5 T was chosen
Exhaustive generation of -critical -free graphs
We describe an algorithm for generating all -critical -free
graphs, based on a method of Ho\`{a}ng et al. Using this algorithm, we prove
that there are only finitely many -critical -free graphs, for
both and . We also show that there are only finitely many
-critical graphs -free graphs. For each case of these cases we
also give the complete lists of critical graphs and vertex-critical graphs.
These results generalize previous work by Hell and Huang, and yield certifying
algorithms for the -colorability problem in the respective classes.
Moreover, we prove that for every , the class of 4-critical planar
-free graphs is finite. We also determine all 27 4-critical planar
-free graphs.
We also prove that every -free graph of girth at least five is
3-colorable, and determine the smallest 4-chromatic -free graph of
girth five. Moreover, we show that every -free graph of girth at least
six and every -free graph of girth at least seven is 3-colorable. This
strengthens results of Golovach et al.Comment: 17 pages, improved girth results. arXiv admin note: text overlap with
arXiv:1504.0697
Critical dynamics of self-gravitating Langevin particles and bacterial populations
We study the critical dynamics of the generalized Smoluchowski-Poisson system
(for self-gravitating Langevin particles) or generalized Keller-Segel model
(for the chemotaxis of bacterial populations). These models [Chavanis & Sire,
PRE, 69, 016116 (2004)] are based on generalized stochastic processes leading
to the Tsallis statistics. The equilibrium states correspond to polytropic
configurations with index similar to polytropic stars in astrophysics. At
the critical index (where is the dimension of space),
there exists a critical temperature (for a given mass) or a
critical mass (for a given temperature). For or
the system tends to an incomplete polytrope confined by the box (in a
bounded domain) or evaporates (in an unbounded domain). For
or the system collapses and forms, in a finite time, a Dirac peak
containing a finite fraction of the total mass surrounded by a halo. This
study extends the critical dynamics of the ordinary Smoluchowski-Poisson system
and Keller-Segel model in corresponding to isothermal configurations with
. We also stress the analogy between the limiting mass of
white dwarf stars (Chandrasekhar's limit) and the critical mass of bacterial
populations in the generalized Keller-Segel model of chemotaxis
Rural men and mental health: their experiences and how they managed
There is a growing awareness that a primary source of information about mental health lies with the consumers. This article reports on a study that interviewed rural men
with the aim of exploring their mental health experiences within a rural environment. The results of the interviews are a number of stories of resilience and survival that
highlight not only the importance of exploring the individuals' perspective of their issues, but also of acknowledging and drawing on their inner strengths. Rural men face a number of challenges that not only increase the risk of mental illness but also decrease the likelihood of them seeking and/or finding professional support. These men's stories, while different from each other, have a common thread of coping. Despite some support from family and friends participants also acknowledged that seeking out professional support could have made the recovery phase easier. Mental health nurses need to be aware, not only of the barrier to professional support but also of the significant resilience that individuals have and how it can be utilised
Machine learning based multiobject tracking for sensor based sorting
Sensor-based sorting provides state-of-the-art solutions for sorting of granular materials. Current systems useline-scanning sensors, which yields a single observation of each object only and no information about their movement. Recent works show that using an area-scan camera bears the potential to decrease both the error in characterization and separation. Using a multiobject tracking system, this enables an estimate of the followed paths as well as the parametrization of an individual motion model per object. While previous works focus on physically-motivated motion models, it has been shown that state-of-the-art machine learning methods achieve an increased
prediction accuracy. In this paper, we present the development of a neural network-based multiobject tracking system and its integration into a laboratory-scale sorting system. Preliminary results show that the novel system achieves results comparable to a highly optimized Kalman filter-based one. A benefit lies in avoiding tiresome manual tuning of parameters of the motion model, as the novel approach allows learning its parameters by provided examples due to its data-driven nature
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