710 research outputs found
VR/Urban: SMSlingshot
In this paper we describe the concept and design objectives of VR/Urban's media intervention tool SMSlingshot, which was presented at the Riga White Night Arts Festival 2009 for the first time
Feasibility of Inconspicuous GAN-generated Adversarial Patches against Object Detection
Standard approaches for adversarial patch generation lead to noisy conspicuous patterns, which are easily recognizable by humans. Recent research has proposed several approaches to generate naturalistic patches using generative adversarial networks (GANs), yet only a few of them were evaluated on the object detection use case. Moreover, the state of the art mostly focuses on suppressing a single large bounding box in input by overlapping it with the patch directly. Suppressing objects near the patch is a different, more complex task. In this work, we have evaluated the existing approaches to generate inconspicuous patches. We have adapted methods, originally developed for different computer vision tasks, to the object detection use case with YOLOv3 and the COCO dataset. We have evaluated two approaches to generate naturalistic patches: by incorporating patch generation into the GAN training process and by using the pretrained GAN. For both cases, we have assessed a trade-off between performance and naturalistic patch appearance. Our experiments have shown, that using a pre-trained GAN helps to gain realistic-looking patches while preserving the performance similar to conventional adversarial patches
Geografische Informationssysteme unter BerĂŒcksichtigung der Oracle Spatial Technik
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Cardiovascular correlates of motor vehicle accident related posttraumatic stress disorder and its successful treatment
Springer Open Choice ArticlePersons with posttraumatic stress disorder (PTSD) have been shown to display elevated baseline cardiovascular activity and a heightened physiological reactivity to trauma-related stimuli. Study 1 examined differences in baseline heart rate (HR) and HR reactivity in 68 survivors of motor vehicle accidents (MVAs) and healthy controls without MVA. MVA survivors with PTSD (n=26), subsyndromal PTSD (n=22), traumatized controls without PTSD (non-PTSD with MVA, n=20) and healthy controls without MVA (HC, n=27) underwent measurement of HR during baseline and exposure to a neutral, positive, negative, and trauma-related picture. PTSD patients showed elevated baseline HR and increased HR reactivity only during exposure to the trauma-related picture. Study 2 investigated whether the elevated physiological responses observed in Study 1 normalized after cognitive behavioral therapy (CBT). We conducted a randomized, controlled treatment trial comparing CBT (n=17) to a Wait-list condition (WLC, n=18). Results showed a greater decrease in HR reactivity for CBT than for WLC. The change in HR reactivity was associated with clinical improvement.This study was supported by the Deutsche Forschungsgemeinschaft (KA 1476/3
A dipolar self-induced bosonic Josephson junction
We propose a new scheme for observing Josephson oscillations and macroscopic
quantum self-trapping phenomena in a toroidally confined Bose-Einstein
condensate: a dipolar self-induced Josephson junction. Polarizing the atoms
perpendicularly to the trap symmetry axis, an effective ring-shaped,
double-well potential is achieved which is induced by the dipolar interaction.
By numerically solving the three-dimensional time-dependent Gross-Pitaevskii
equation we show that coherent tunneling phenomena such as Josephson
oscillations and quantum self-trapping can take place. The dynamics in the
self-induced junction can be qualitatively described by a two-mode model taking
into account both s-wave and dipolar interactions.Comment: Major changes. Accepted for publication in EP
Three strongly correlated charged bosons in a one-dimensional harmonic trap: natural orbital occupancies
We study a one-dimensional system composed of three charged bosons confined
in an external harmonic potential. More precisely, we investigate the
ground-state correlation properties of the system, paying particular attention
to the strong-interaction limit. We explain for the first time the nature of
the degeneracies appearing in this limit in the spectrum of the reduced density
matrix. An explicit representation of the asymptotic natural orbitals and their
occupancies is given in terms of some integral equations.Comment: 6 pages, 4 figures, To appear in European Physical Journal
Pharmacological Activation of Soluble Guanylate Cyclase Protects the Heart Against Ischemic Injury
Recursive formulation of the multiconfigurational time-dependent Hartree method for fermions, bosons and mixtures thereof in terms of one-body density operators
The multiconfigurational time-dependent Hartree method (MCTDH) [Chem. Phys.
Lett. {\bf 165}, 73 (1990); J. Chem. Phys. {\bf 97}, 3199 (1992)] is
celebrating nowadays entering its third decade of tackling numerically-exactly
a broad range of correlated multi-dimensional non-equilibrium quantum dynamical
systems. Taking in recent years particles' statistics explicitly into account,
within the MCTDH for fermions (MCTDHF) and for bosons (MCTDHB), has opened up
further opportunities to treat larger systems of interacting identical
particles, primarily in laser-atom and cold-atom physics. With the increase of
experimental capabilities to simultaneously trap mixtures of two, three, and
possibly even multiple kinds of interacting composite identical particles
together, we set up the stage in the present work and specify the MCTDH method
for such cases. Explicitly, the MCTDH method for systems with three kinds of
identical particles interacting via all combinations of two- and three-body
forces is presented, and the resulting equations-of-motion are briefly
discussed. All four possible mixtures of fermions and bosons are presented in a
unified manner. Particular attention is paid to represent the coefficients'
part of the equations-of-motion in a compact recursive form in terms of
one-body density operators only. The recursion utilizes the recently proposed
Combinadic-based mapping for fermionic and bosonic operators in Fock space
[Phys. Rev. A {\bf 81}, 022124 (2010)] and successfully applied and implemented
within MCTDHB. Our work sheds new light on the representation of the
coefficients' part in MCTDHF and MCTDHB without resorting to the matrix
elements of the many-body Hamiltonian with respect to the time-dependent
configurations. It suggests a recipe for efficient implementation of the
schemes derived here for mixtures which is suitable for parallelization.Comment: 43 page
Bose-Hubbard model with occupation dependent parameters
We study the ground-state properties of ultracold bosons in an optical
lattice in the regime of strong interactions. The system is described by a
non-standard Bose-Hubbard model with both occupation-dependent tunneling and
on-site interaction. We find that for sufficiently strong coupling the system
features a phase-transition from a Mott insulator with one particle per site to
a superfluid of spatially extended particle pairs living on top of the Mott
background -- instead of the usual transition to a superfluid of single
particles/holes. Increasing the interaction further, a superfluid of particle
pairs localized on a single site (rather than being extended) on top of the
Mott background appears. This happens at the same interaction strength where
the Mott-insulator phase with 2 particles per site is destroyed completely by
particle-hole fluctuations for arbitrarily small tunneling. In another regime,
characterized by weak interaction, but high occupation numbers, we observe a
dynamical instability in the superfluid excitation spectrum. The new ground
state is a superfluid, forming a 2D slab, localized along one spatial direction
that is spontaneously chosen.Comment: 16 pages, 4 figure
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