1,457 research outputs found
Trade Union Politics as a Countermovement? A Polaniyan Perspective
The article develops a conceptual proposal for the inquiry of trade unions. On the basis of Karl Polanyis theory, four patterns of political mobilization applied by trade unions in the current Transformation are pointed out
From photos to sketches-how humans and deep neural networks process objects across different levels of visual abstraction
Line drawings convey meaning with just a few strokes. Despite strong simplifications, humans can recognize objects depicted in such abstracted images without effort. To what degree do deep convolutional neural networks (CNNs) mirror this human ability to generalize to abstracted object images? While CNNs trained on natural images have been shown to exhibit poor classification performance on drawings, other work has demonstrated highly similar latent representations in the networks for abstracted and natural images. Here, we address these seemingly conflicting findings by analyzing the activation patterns of a CNN trained on natural images across a set of photographs, drawings, and sketches of the same objects and comparing them to human behavior. We find a highly similar representational structure across levels of visual abstraction in early and intermediate layers of the network. This similarity, however, does not translate to later stages in the network, resulting in low classification performance for drawings and sketches. We identified that texture bias in CNNs contributes to the dissimilar representational structure in late layers and the poor performance on drawings. Finally, by fine-tuning late network layers with object drawings, we show that performance can be largely restored, demonstrating the general utility of features learned on natural images in early and intermediate layers for the recognition of drawings. In conclusion, generalization to abstracted images, such as drawings, seems to be an emergent property of CNNs trained on natural images, which is, however, suppressed by domain-related biases that arise during later processing stages in the network
[Rezension] Ursachen politischen Handelns? Rezension zu Andreas Pettenkofer, "Die Entstehung der grünen Politik"
Gangsta-Rap als ambivalente Subjektkultur
Der Beitrag untersucht die Sprecherposition des deutschen Gangsta-Rappers mit Migrationshintergrund aus kultursoziologischer Perspektive und lotet den inszenatorischen Spielraum des Subjekts in einem normativen Szenediskurs aus, der umschlossen ist von soziokulturell bedeutsamen, übergeordneten Diskursen. Gangsta-Rap wird als popkulturelle Bühne und umkämpfter Ort betrachtet, an dem sich die Protagonisten vor dem Hintergrund gesellschaftlich kursierender Stereotype und Zuschreibungen positionieren. In diesem Sinne interpretieren wir die bild- und textbasierten Inszenierungen als Produkte der Verhandlung von Kategorien wie Geschlecht, Ethnizität und Klasse. In ästhetisierter Form wirken die Performances auf die Gesellschaft zurück – mit dem Effekt einer polarisierenden Diskussion
WASP-14 b: Transit Timing analysis of 19 light curves
Although WASP-14 b is one of the most massive and densest exoplanets on a
tight and eccentric orbit, it has never been a target of photometric follow-up
monitoring or dedicated observing campaigns. We report on new photometric
transit observations of WASP-14 b obtained within the framework of "Transit
Timing Variations @ Young Exoplanet Transit Initiative" (TTV@YETI). We
collected 19 light-curves of 13 individual transit events using six telescopes
located in five observatories distributed in Europe and Asia. From light curve
modelling, we determined the planetary, stellar, and geometrical properties of
the system and found them in agreement with the values from the discovery
paper. A test of the robustness of the transit times revealed that in case of a
non-reproducible transit shape the uncertainties may be underestimated even
with a wavelet-based error estimation methods. For the timing analysis we
included two publicly available transit times from 2007 and 2009. The long
observation period of seven years (2007-2013) allowed us to refine the transit
ephemeris. We derived an orbital period 1.2 s longer and 10 times more precise
than the one given in the discovery paper. We found no significant periodic
signal in the timing-residuals and, hence, no evidence for TTV in the system.Comment: 12 pages, 10 figures, 7 table
No variations in transit times for Qatar-1 b
The transiting hot Jupiter planet Qatar-1 b was presented to exhibit
variations in transit times that could be of perturbative nature. A hot Jupiter
with a planetary companion on a nearby orbit would constitute an unprecedented
planetary configuration, important for theories of formation and evolution of
planetary systems. We performed a photometric follow-up campaign to confirm or
refute transit timing variations. We extend the baseline of transit
observations by acquiring 18 new transit light curves acquired with 0.6-2.0 m
telescopes. These photometric time series, together with data available in the
literature, were analyzed in a homogenous way to derive reliable transit
parameters and their uncertainties. We show that the dataset of transit times
is consistent with a linear ephemeris leaving no hint for any periodic
variations with a range of 1 min. We find no compelling evidence for the
existence of a close-in planetary companion to Qatar-1 b. This finding is in
line with a paradigm that hot Jupiters are not components of compact
multi-planetary systems. Based on dynamical simulations, we place tighter
constraints on a mass of any fictitious nearby planet in the system.
Furthermore, new transit light curves allowed us to redetermine system
parameters with the precision better than that reported in previous studies.
Our values generally agree with previous determinations.Comment: Accepted for publication in A&
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