349 research outputs found
Targeted Adversarial Attacks on Wind Power Forecasts
In recent years, researchers proposed a variety of deep learning models for
wind power forecasting. These models predict the wind power generation of wind
farms or entire regions more accurately than traditional machine learning
algorithms or physical models. However, latest research has shown that deep
learning models can often be manipulated by adversarial attacks. Since wind
power forecasts are essential for the stability of modern power systems, it is
important to protect them from this threat. In this work, we investigate the
vulnerability of two different forecasting models to targeted, semitargeted,
and untargeted adversarial attacks. We consider a Long Short-Term Memory (LSTM)
network for predicting the power generation of a wind farm and a Convolutional
Neural Network (CNN) for forecasting the wind power generation throughout
Germany. Moreover, we propose the Total Adversarial Robustness Score (TARS), an
evaluation metric for quantifying the robustness of regression models to
targeted and semi-targeted adversarial attacks. It assesses the impact of
attacks on the model's performance, as well as the extent to which the
attacker's goal was achieved, by assigning a score between 0 (very vulnerable)
and 1 (very robust). In our experiments, the LSTM forecasting model was fairly
robust and achieved a TARS value of over 0.81 for all adversarial attacks
investigated. The CNN forecasting model only achieved TARS values below 0.06
when trained ordinarily, and was thus very vulnerable. Yet, its robustness
could be significantly improved by adversarial training, which always resulted
in a TARS above 0.46.Comment: 20 pages, including appendix, 12 figure
Проблемы информационного обеспечения физической культуры и спорта
A formation process for semiconductor quantum dots based on a surface instability induced by ion sputtering under normal incidence is presented. Crystalline dots 35 nanometers in diameter and arranged in a regular hexagonal lattice were produced on gallium antimonide surfaces. The formation mechanism relies on a natural self-organization mechanism that occurs during the erosion of surfaces, which is based on the interplay between roughening induced by ion sputtering and smoothing due to surface diffusion
Visual Motion Responses in the Posterior Cingulate Sulcus: A Comparison to V5/MT and MST
Motion processing regions apart from V5+/MT+ are still relatively poorly understood. Here, we used functional magnetic resonance imaging to perform a detailed functional analysis of the recently described cingulate sulcus visual area (CSv) in the dorsal posterior cingulate cortex. We used distinct types of visual motion stimuli to compare CSv with V5/MT and MST, including a visual pursuit paradigm. Both V5/MT and MST preferred 3D flow over 2D planar motion, responded less yet substantially to random motion, had a strong preference for contralateral versus ipsilateral stimulation, and responded nearly equally to contralateral and to full-field stimuli. In contrast, CSv had a pronounced preference to 2D planar motion over 3D flow, did not respond to random motion, had a weak and nonsignificant lateralization that was significantly smaller than that of MST, and strongly preferred full-field over contralateral stimuli. In addition, CSv had a better capability to integrate eye movements with retinal motion compared with V5/MT and MST. CSv thus differs from V5+/MT+ by its unique preference to full-field, coherent, and planar motion cues. These results place CSv in a good position to process visual cues related to self-induced motion, in particular those associated to eye or lateral head movements
The QCD/SM Working Group: Summary Report
This Report documents the results obtained by the Working Group on Quantum
ChromoDynamics and the Standard Model for the Workshop ``Physics at TeV
Colliders'', Les Houches, France, 21 May - 1 June 2001. The account of
uncertainties in Parton Distribution Functions is reviewed. Progresses in the
description of multiparton final states at Next-to-Leading Order and the
extension of calculations for precision QCD observables beyond this order are
summarized. Various issues concerning the relevance of resummation for
observables at TeV colliders is examined. Improvements to algorithms of jet
reconstruction are discussed and predictions for diphoton and photon pi-zero
production at the LHC are made for kinematic variables of interest regarding
searches for a Higgs boson decaying into two photons. Finally, several
improvements implemented in Monte-Carlo event generators are documented
Two real parton contributions to non-singlet kernels for exclusive QCD DGLAP evolution
Results for the two real parton differential distributions needed for
implementing a next-to-leading order (NLO) parton shower Monte Carlo are
presented. They are also integrated over the phase space in order to provide
solid numerical control of the MC codes and for the discussion of the
differences between the standard factorization and Monte Carlo
implementation at the level of inclusive NLO evolution kernels. Presented
results cover the class of non-singlet diagrams entering into NLO kernels. The
classic work of Curci-Furmanski-Pertonzio was used as a guide in the
calculations.Comment: 34 pages, 3 figure
Four Loop Massless Propagators: an Algebraic Evaluation of All Master Integrals
The old "glue--and--cut" symmetry of massless propagators, first established
in [1], leads --- after reduction to master integrals is performed --- to a
host of non-trivial relations between the latter. The relations constrain the
master integrals so tightly that they all can be analytically expressed in
terms of only few, essentially trivial, watermelon-like integrals. As a
consequence we arrive at explicit analytical results for all master integrals
appearing in the process of reduction of massless propagators at three and four
loops. The transcendental structure of the results suggests a clean explanation
of the well-known mystery of the absence of even zetas (zeta_{2n}) in the Adler
function and other similar functions essentially reducible to the massless
propagators. Once a reduction of massless propagators at five loops is
available, our approach should be also applicable for explicit performing the
corresponding five-loop master integrals.Comment: 34 pages, few typos have been fixed, references and acknowledgements
have been updated. Results for master integrals (together with some auxiliary
information) are now available in
http://www-ttp.physik.uni-karlsruhe.de/Progdata/ttp10/ttp10-18
Hopf algebras, coproducts and symbols: an application to Higgs boson amplitudes
We show how the Hopf algebra structure of multiple polylogarithms can be used
to simplify complicated expressions for multi-loop amplitudes in perturbative
quantum field theory and we argue that, unlike the recently popularized
symbol-based approach, the coproduct incorporates information about the zeta
values. We illustrate our approach by rewriting the two-loop helicity
amplitudes for a Higgs boson plus three gluons in a simplified and compact form
involving only classical polylogarithms.Comment: 46 page
QCD
We discuss issues of QCD at the LHC including parton distributions, Monte
Carlo event generators, the available next-to-leading order calculations,
resummation, photon production, small x physics, double parton scattering, and
backgrounds to Higgs production.Comment: 115 pages, Latex, 47 figures, to appear in the Report of the ``1999
CERN Workshop on SM Physics (and more) at the LHC'', S. Catani, M. Dittmar,
D. Soper, W.J. Stirling, S. Tapprogge (convenors
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