2,782 research outputs found
Who can wait for the future? A personality perspective
Who can wait for larger, delayed rewards rather than smaller, immediate ones? Delay discounting (DD) measures the rate at which subjective value of an outcome decreases as the length of time to obtaining it increases. Previous work has shown that greater DD predicts negative academic, social, and health outcomes. Yet, little is known about who is likely to engage in greater or less DD. Taking a personality perspective, in a large sample (N = 5,888), we found that greater DD was predicted by low openness and conscientiousness and higher extraversion and neuroticism. Smaller amounts were also discounted more than larger amounts; furthermore, amount magnified the effects of openness and neuroticism on DD. Our findings show that personality is one predictor of individual differences in DD-an important implication for intervention approaches targeted at DD. © The Author(s) 2013.Vaishali Mahalingam was supported by a ‘Cambridge Nehru Bursary’ from the Nehru Trust for Cambridge University. David Stillwell was supported by an ESRC studentship (ES/F021801/1). He also receives revenue as an owner of the ‘My Personality’ website. Michal Kosinski received funding from Boeing Corporation
Approaches for improving cutting processes and machine too in re-contouring
Re-contouring in the repair process of aircraft engine blades and vanes is a crucial task. Highest demands are made on the geometrical accuracy as well as on the machined surface of the part. Complexity rises even more due to the unique part characteristic originating from the operation and repair history. This requires well-designed processes and machine tool technologies. In this paper, approaches for coping with these challenges and improving the re-contouring process are described and discussed. This includes an advanced process simulation with its capabilities to accurately depict different material areas and predict process forces. Beyond, experimental investigations on workpiece-tooldeflection are presented. Finally, a machine tool prototype with a novel electromagnetic guiding system is introduced and the benefits of this technology in the field of repair are outlined.DFG/CRC/87
Learning to Extract Motion from Videos in Convolutional Neural Networks
This paper shows how to extract dense optical flow from videos with a
convolutional neural network (CNN). The proposed model constitutes a potential
building block for deeper architectures to allow using motion without resorting
to an external algorithm, \eg for recognition in videos. We derive our network
architecture from signal processing principles to provide desired invariances
to image contrast, phase and texture. We constrain weights within the network
to enforce strict rotation invariance and substantially reduce the number of
parameters to learn. We demonstrate end-to-end training on only 8 sequences of
the Middlebury dataset, orders of magnitude less than competing CNN-based
motion estimation methods, and obtain comparable performance to classical
methods on the Middlebury benchmark. Importantly, our method outputs a
distributed representation of motion that allows representing multiple,
transparent motions, and dynamic textures. Our contributions on network design
and rotation invariance offer insights nonspecific to motion estimation
Adaptive-Aggressive Traders Don't Dominate
For more than a decade Vytelingum's Adaptive-Aggressive (AA) algorithm has
been recognized as the best-performing automated auction-market trading-agent
strategy currently known in the AI/Agents literature; in this paper, we
demonstrate that it is in fact routinely outperformed by another algorithm when
exhaustively tested across a sufficiently wide range of market scenarios. The
novel step taken here is to use large-scale compute facilities to brute-force
exhaustively evaluate AA in a variety of market environments based on those
used for testing it in the original publications. Our results show that even in
these simple environments AA is consistently out-performed by IBM's GDX
algorithm, first published in 2002. We summarize here results from more than
one million market simulation experiments, orders of magnitude more testing
than was reported in the original publications that first introduced AA. A 2019
ICAART paper by Cliff claimed that AA's failings were revealed by testing it in
more realistic experiments, with conditions closer to those found in real
financial markets, but here we demonstrate that even in the simple experiment
conditions that were used in the original AA papers, exhaustive testing shows
AA to be outperformed by GDX. We close this paper with a discussion of the
methodological implications of our work: any results from previous papers where
any one trading algorithm is claimed to be superior to others on the basis of
only a few thousand trials are probably best treated with some suspicion now.
The rise of cloud computing means that the compute-power necessary to subject
trading algorithms to millions of trials over a wide range of conditions is
readily available at reasonable cost: we should make use of this; exhaustive
testing such as is shown here should be the norm in future evaluations and
comparisons of new trading algorithms.Comment: To be published as a chapter in "Agents and Artificial Intelligence"
edited by Jaap van den Herik, Ana Paula Rocha, and Luc Steels; forthcoming
2019/2020. 24 Pages, 1 Figure, 7 Table
Current Helicity and Twist as Two Indicators of The Mirror Asymmetry of solar Magnetic Fields
A comparison between the two tracers of magnetic field mirror asymmetry in
solar active regions, twist and current helicity, is presented. It is shown
that for individual active regions these tracers do not possess visible
similarity while averaging by time over the solar cycle, or by latitude,
reveals similarities in their behaviour. The main property of the dataset is
anti-symmetry over the solar equator. Considering the evolution of helical
properties over the solar cycle we find signatures of a possible sign change at
the beginning of the cycle, though more systematic observational data are
required for a definite confirmation. We discuss the role of both tracers in
the context of the solar dynamo theory.Comment: 14 pages, 6 figure
Turbulence in the Solar Atmosphere: Manifestations and Diagnostics via Solar Image Processing
Intermittent magnetohydrodynamical turbulence is most likely at work in the
magnetized solar atmosphere. As a result, an array of scaling and multi-scaling
image-processing techniques can be used to measure the expected
self-organization of solar magnetic fields. While these techniques advance our
understanding of the physical system at work, it is unclear whether they can be
used to predict solar eruptions, thus obtaining a practical significance for
space weather. We address part of this problem by focusing on solar active
regions and by investigating the usefulness of scaling and multi-scaling
image-processing techniques in solar flare prediction. Since solar flares
exhibit spatial and temporal intermittency, we suggest that they are the
products of instabilities subject to a critical threshold in a turbulent
magnetic configuration. The identification of this threshold in scaling and
multi-scaling spectra would then contribute meaningfully to the prediction of
solar flares. We find that the fractal dimension of solar magnetic fields and
their multi-fractal spectrum of generalized correlation dimensions do not have
significant predictive ability. The respective multi-fractal structure
functions and their inertial-range scaling exponents, however, probably provide
some statistical distinguishing features between flaring and non-flaring active
regions. More importantly, the temporal evolution of the above scaling
exponents in flaring active regions probably shows a distinct behavior starting
a few hours prior to a flare and therefore this temporal behavior may be
practically useful in flare prediction. The results of this study need to be
validated by more comprehensive works over a large number of solar active
regions.Comment: 26 pages, 7 figure
3D MHD Flux Emergence Experiments: Idealized models and coronal interactions
This paper reviews some of the many 3D numerical experiments of the emergence
of magnetic fields from the solar interior and the subsequent interaction with
the pre-existing coronal magnetic field. The models described here are
idealized, in the sense that the internal energy equation only involves the
adiabatic, Ohmic and viscous shock heating terms. However, provided the main
aim is to investigate the dynamical evolution, this is adequate. Many
interesting observational phenomena are explained by these models in a
self-consistent manner.Comment: Review article, accepted for publication in Solar Physic
Constrained Optimization Approaches to Estimation of Structural Models
Estimating structural models is often viewed as computationally difficult, an impression partly due to a focus on the nested fixed-point (NFXP) approach. We propose a new constrained optimization approach for structural estimation. We show that our approach and the NFXP algorithm solve the same estimation problem, and yield the same estimates. Computationally, our approach can have speed advantages because we do not repeatedly solve the structural equation at each guess of structural parameters. Monte Carlo experiments on the canonical Zurcher bus-repair model demonstrate that the constrained optimization approach can be significantly faster
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