Calculation of the Cherenkov light yield from electromagnetic cascades in ice with Geant4

In this work we investigate and parameterize the amount and angular distribution of Cherenkov photons which are generated by electromagnetic cascades in water or ice. We simulate electromagnetic cascades with Geant4 for primary electrons, positrons and photons with energies ranging from 1 GeV to 10 TeV. We parameterize the total Cherenkov light yield as a function of energy, the longitudinal evolution of the Cherenkov emission along the cascade-axis and the angular distribution of photons. Furthermore, we investigate the fluctuations of the total light yield, the fluctuations in azimuth and changes of the emission with increasing age of the cascade

Promptformer: Prompted Conformer Transducer for ASR

Context cues carry information which can improve multi-turn interactions in automatic speech recognition (ASR) systems. In this paper, we introduce a novel mechanism inspired by hyper-prompting to fuse textual context with acoustic representations in the attention mechanism. Results on a test set with multi-turn interactions show that our method achieves 5.9% relative word error rate reduction (rWERR) over a strong baseline. We show that our method does not degrade in the absence of context and leads to improvements even if the model is trained without context. We further show that leveraging a pre-trained sentence-piece model for context embedding generation can outperform an external BERT model

Simulation of SVPWM Based Multivariable Control Method for a DFIG Wind Energy System

This paper deals with a variable speed device toproduce electrical energy on a power network based on adoubly-fed induction machine used in generating mode(DFIG) in wind energy system by using SVPWM powertransfer matrix. This paper presents a modeling and controlapproach which uses instantaneous real and reactive powerinstead of dq components of currents in a vector controlscheme. The main features of the proposed model comparedto conventional models in the dq frame of reference arerobustness and simplicity of realization. The sequential loopclosing technique is adopted to design a multivariable controlsystem including six compensators for a DFIG wind energysystem to capture the maximum wind power and to inject therequired reactive power to the generator. In this paperSVPWM method is used for better controlling of converters.It also provides fault ride through method to protect theconverter during a fault. The time-domain simulation of thestudy system is presented by using MATLAB Simulink to testthe system robustness, to validate the proposed model and toshow the enhanced tracking capability

Measurement of High-Energy Muon Neutrinos with the IceCube Neutrino Observatory

More than a century after their discovery the origin of high-energy cosmic rays remains unknown. With the discovery of high-energy astrophysical neutrinos by the IceCube collaboration a new window into the universe has been opened. The discovery relies on high-energy neutrinos which interact within the instrumented volume of the detector. A complementary search strategy is the selection of charged-current muon neutrino events which can interact outside the instrumented volume. Due to the large muon range the effective area is significantly larger, but the field of view is restricted to the Northern Hemisphere. In this thesis the selection of muon neutrino events using ''Boosted Decision Trees`` is presented. In total more than 350,000 neutrino candidates have been selected using data from 2009 through 2015. The majority of these events are atmospheric neutrinos and the contribution of atmospheric muons is negligible. Due to an increased selection efficiency and using additional years of data, the statistics increase by more than an order of magnitude compared to previous event selections. The final dataset has been analyzed using two-dimensional likelihood approach in reconstructed muon energy and zenith. The measured astrophysical neutrino flux is compatible with an isotropic, unbroken power-law flux with a normalization of $(0.90^{+0.30}_{-0.27})\times 10^{-18}\,\mathrm{GeV^{-1}\,cm^{-2}\,sr^{-1}\,s^{-1}}$ at $100\,\mathrm{TeV}$ and a spectral index of $2.13 \pm 0.13$. A neutrino flux of only atmospheric origin can be rejected with a significance of $5.6\,{\sigma}$. Compared to previous IceCube measurements with lower energy thresholds the measured spectrum is considerably harder indicating a spectral break in the astrophysical neutrino spectrum of unknown origin. Among the selected events is the highest-energy neutrino observed to date. The event has a reconstructed muon energy of $(4.5\pm1.2)\,\mathrm{PeV}$ and its probability of being of atmospheric origin is below $0.005\%$. Its arrival direction has been reconstructed as $\mathrm{Dec(J2000)}=(11.42\pm0.17)^\circ$ and $\mathrm{RA(J2000)}=(110.63_{-0.55}^{+0.46})^\circ$. Using Monte Carlo simulations the deposited energy within the instrumented volume can be estimated as $(2.6\pm0.3)\,\mathrm{PeV}$ and the median neutrino energy as $8.7\,\mathrm{PeV}$. Even though a muon neutrino is the most likely origin ($88\%$), the probability of a tau ($11\%$) and an electron neutrino ($1\%$) are not negligible. No correlation with high-energy $\gamma$-ray sources has been found. Follow-up analyses with HAWC, HESS, MAGIC and XMM-Newton yield no indication for a source as well. In addition to the highest-energy event 28 events with muon energies above $200\,\mathrm{TeV}$ have been found. No statistical significant correlation with $\gamma$-ray sources could be established