Application of Deep Learning methods to analysis of Imaging Atmospheric Cherenkov Telescopes data

Ground based gamma-ray observations with Imaging Atmospheric Cherenkov Telescopes (IACTs) play a significant role in the discovery of very high energy (E > 100 GeV) gamma-ray emitters. The analysis of IACT data demands a highly efficient background rejection technique, as well as methods to accurately determine the energy of the recorded gamma-ray and the position of its source in the sky. We present results for background rejection and signal direction reconstruction from first studies of a novel data analysis scheme for IACT measurements. The new analysis is based on a set of Convolutional Neural Networks (CNNs) applied to images from the four H.E.S.S. phase-I telescopes. As the H.E.S.S. cameras pixels are arranged in a hexagonal array, we demonstrate two ways to use such image data to train CNNs: by resampling the images to a square grid and by applying modified convolution kernels that conserve the hexagonal grid properties. The networks were trained on sets of Monte-Carlo simulated events and tested on both simulations and measured data from the H.E.S.S. array. A comparison between the CNN analysis to current state-of-the-art algorithms reveals a clear improvement in background rejection performance. When applied to H.E.S.S. observation data, the CNN direction reconstruction performs at a similar level as traditional methods. These results serve as a proof-of-concept for the application of CNNs to the analysis of events recorded by IACTs

Probing Convolutional Neural Networks for Event Reconstruction in {\gamma}-Ray Astronomy with Cherenkov Telescopes

A dramatic progress in the field of computer vision has been made in recent years by applying deep learning techniques. State-of-the-art performance in image recognition is thereby reached with Convolutional Neural Networks (CNNs). CNNs are a powerful class of artificial neural networks, characterized by requiring fewer connections and free parameters than traditional neural networks and exploiting spatial symmetries in the input data. Moreover, CNNs have the ability to automatically extract general characteristic features from data sets and create abstract data representations which can perform very robust predictions. This suggests that experiments using Cherenkov telescopes could harness these powerful machine learning algorithms to improve the analysis of particle-induced air-showers, where the properties of primary shower particles are reconstructed from shower images recorded by the telescopes. In this work, we present initial results of a CNN-based analysis for background rejection and shower reconstruction, utilizing simulation data from the H.E.S.S. experiment. We concentrate on supervised training methods and outline the influence of image sampling on the performance of the CNN-model predictions.Comment: 8 pages, 4 figures, Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Busan, Kore

6sterreichische Wasser- und Abfallwirtschaft / Grundlegende Erkenntnisse im Rahmen des Pilotprojekt Bad Deutsch-Altenburg : Die Bedeutung der Stromsohle und Uferzonen f\ufcr \uf6kologische Prozesse und Artengemeinschaften an einem stark regulierten Fluss, der Donau

Fl\ufcsse ben\uf6tigen f\ufcr eine langfristige \uf6kologische Stabilit\ue4t \u2013 Bereiche, die bei verschiedenen Abflusssituationen als hoch produktive Lebensr\ue4ume verf\ufcgbar sind und entsprechend mit dem Fluss in Austausch stehen. Diese Retentionsbereiche oder bioaktive Zonen sind wichtig f\ufcr die flusseigene Tierwelt als Refugialr\ue4ume (z. B. Makrozoobenthos und Fische) oder bestimmte Entwicklungsstadien (z. B. Jungfische), dienen benthischen Algengemeinschaften zum Aufbau von Biomasse und sind damit Grundlage f\ufcr das Nahrungsnetz des Flusses sowie den Stoffr\ufcckhalt und Umbau (z. B. N\ue4hrstoffaufnahme). Vor allem w\ue4hrend Niederwasser sind die Uferbereiche und die Stromsohle selbst von wesentlicher Bedeutung, aber in ihrer Auspr\ue4gung durch Regulierungsma fnahmen deutlich eingeschr\ue4nkt. Ein grundlegendes Verst\ue4ndnis der Abl\ue4ufe und funktionalen Zusammenh\ue4nge ist erforderlich, damit im Rahmen von wasserbaulichen Ma fnahmen negative Konsequenzen hintangehalten werden k\uf6nnen bzw. der \uf6kologische Zustand wieder verbessert werden kann. Im Rahmen des Pilotprojekts Bad Deutsch-Altenburg an der Donau \uf6stlich von Wien ist daher nicht nur ein Monitoring der flussbaulichen Ma fnahmenumsetzung erforderlich, sondern auch ein wissenschaftlicher Erkenntnisgewinn \ufcber grundlegende Zusammenh\ue4nge und biologische Abl\ue4ufe, um optimierte Ma fnahmen zum Einsatz bringen zu k\uf6nnen. In diesem Artikel werden Ergebnisse mehrj\ue4hriger Forschungsarbeiten in den Tiefenzonen der Donau und typischen Uferzonenlebensr\ue4umen f\ufcr die Organismengruppen benthische Algen, Makrozoobenthos und Fische pr\ue4sentiert.To ensure a long-term ecological stability, rivers need areas that are available at different discharge situations as highly productive habitats which are connected with the river. These retention areas or biologically active zones are important for the riverine communities as refuge (e.g. benthic macroinvertebrates and fish) or the development of benthic algae communities as basis for the riverine food web as well as retention zones to perform various ecosystem services (e.g. nutrient retention). Especially during low water level situations, the river shorelines and the river bed itself are of significant importance, but highly degraded in intensely regulated river systems such as the Danube River. A basic understanding of the processes and functional correlations is required to avoid negative consequences of engineering measures applied and to improve the ecological conditions. In the framework of the pilot project Bad Deutsch-Altenburg in the Danube River east of Vienna not only monitoring the implementation of engineering measures is required, but also scientific knowledge gained about basic ecological relationships and potential responses of riverine communities. This article presents results of several years of investigations on the distribution and development of three organism groups (benthic algae, benthic macroinvertebrates and fish) along different riparian structures and in the river bed of the Danube River

6sterreichische Wasser- und Abfallwirtschaft / Integrierte gew\ue4sser\uf6kologische Modellans\ue4tze zur Beurteilung von Gew\ue4sservernetzungsvarianten am Beispiel der Unteren Lobau

Weltweit z\ue4hlen Flie fgew\ue4ssersysteme und Auenlandschaften zu den gef\ue4hrdetsten 6kosystemen. Flussregulierungs- und Verbauungsma fnahmen haben diese Systeme von ihren nat\ufcrlichen Wasserstandsschwankungen bzw. dem Wasseraustausch mit dem Fluss entkoppelt und f\ufchren damit zu einer Verlandung ehemaliger hochdynamischer Habitate. Gezielte Managementma fnahmen k\uf6nnen diesen Entwicklungen entgegenwirken, m\ufcssen vor Umsetzung aber auf ihre Auswirkungen hin \ufcberpr\ufcft werden. Grunds\ue4tzlich initiieren alle Restaurationsma fnahmen grundlegende Prozesse im Fluss-Auensystem, auf die Arten mit unterschiedlichen Habitatanspr\ufcchen und unterschiedlichem Schutzstatus verschieden reagieren k\uf6nnen. Eine M\uf6glichkeit einer wissenschaftlich fundierten Prognose von hydrologischen Managementma fnahmen wird in diesem Artikel am Beispiel der Verwendung von Habitatmodellen f\ufcr eine Studie in der Unteren Lobau vorgestellt. Die Untere Lobau ist eine Auenlandschaft im Osten von Wien, n\uf6rdlich der Donau. Sie ist Teil des Nationalparks Donau-Auen und gesch\ufctzter FFH-Lebensraum. Vor der Donauregulierung Ende des 19. Jahrhunderts war die Untere Lobau ein dynamisches Auengebiet, aber die heute vorherrschenden Verlandungsprozesse bedrohen dieses in Europa selten gewordene 6kosystem. F\ufcr dieses Gebiet wurden drei Managementvarianten untersucht: 1) Nullvariante \u2013 Das Ausbleiben jeglicher Ma fnahmen mit einer Fortsetzung der Verlandungsprozesse; 2) Dotation \u2013 Die Zufuhr einer gerade ausreichenden Menge an Wasser, um Wasserfl\ue4chen gem\ue4 f dem Status quo zu erhalten; 3) Anbindung \u2013 Das Herstellen einer stromaufw\ue4rtigen Verbindung zum Hauptstrom der Donau, was eine Rheophilisierung des Systems und zumindest eine Ann\ue4herung an historische Verh\ue4ltnisse darstellt. Auf Basis modellierter Umweltdaten und Habitatpr\ue4ferenzen wurden mittels bin\ue4r-logistischer Regressionen von ausgew\ue4hlten Arten verschiedenster Gruppen potenzielle Habitatfl\ue4chen (Weighted Usable Areas) berechnet. Die Qualit\ue4t der Modellergebnisse konnte unterstreichen, dass die Modellierungen die hydrologischen Ma fnahmen mit ihrem Einfluss auf die Bioz\uf6nose gut beschreiben und damit eine wertvolle Hilfe in der Entscheidungsfindung im Gew\ue4ssermanagement sein k\uf6nnen.Floodplains and wetlands are among the most endangered ecosystems worldwide. River-regulation and flood protection measures cut off these formerly highly dynamic systems from their natural water level fluctuations and water exchange conditions leading to siltation processes. Restoration measures to counteract these developments need to be assessed for the effect on currently established habitats and communities in order to estimate their effects, as species with different habitat preferences and different protection status do react distinctly different. This article will present how habitat modelling was used in a case study of the Untere Lobau to assess and predict the effects of potential management measures. The Untere Lobau is a wetland ecosystem of the Danube east of Vienna. It is part of the national park Donau-Auen and a protected area according to the EU habitat-directive. Prior to the river regulation, at the end of the 19th century, the Untere Lobau was a dynamic floodplain. Today, siltation processes endanger especially the status of the aquatic habitats. Three management options were investigated: 1) business as usual \u2013 No implementation of additional hydrological measures, thus siltation processes are not mitigated; 2) a water enhancement scheme \u2013 A small amount of water is supplied to preserve the water bodies at the current status quo; 3) partly reconnection \u2013 An upstream reconnection of the floodplain to the main channel of the Danube, leading to a more rheophilic characteristic of the system moving towards conditions prior regulation. Based on a model approach and calculating habitat preferences via binary logistic regressions of selected species from different organism groups, an increase or decrease of available suitable habitat area (weighted usable areas) could be estimated. This study proofed clearly that models can assess the effects of hydrological management measures on the biocenosis and that they are a valuable tool for supporting the decision taking process in wetland management

Sensitivity analysis of a climate vulnerability index - a case study from Indian watershed development programmes

Background: This paper presents a detailed analysis of a composite Climate Vulnerability Index (CVI) to examine and compare climate change vulnerability and its dimensions adaptive capacity, sensitivity and exposure. Thereby, we are mainly interested on climate change vulnerability at community-level watershed development programmes and how the different implementing agencies could help to address the problems associated with climate change in future planning and implementation. Method: The primary data used for this study was obtained from household surveys (n=215) in three watershed communities of Kerala, India. We use bootstrap sampling and a leave-one-out sensitivity analysis to compare the climate vulnerability of the three examined watersheds in detail. By introducing the bootstrapping method and sensitivity analysis into the research field of climate vulnerability, the paper describes significant differences in CVI values and the influencing indicators to the overall vulnerability at the watershed community level. Results The results show that there are significant differences in the exposure and sensitivity dimensions of vulnerability even if the overall CVI shows less variability and no significant differences among the three watersheds. The sensitivity analysis emphasizes that Livelihood Strategies and SSocial Network are the most influencing major components of vulnerability. This suggests that implementing agencies should focus on these two major components in order to improve the watershed development programmes. Conclusion The bootstrapping approach is transferable to evaluate the degree of influence of indicators on a composite index like the CVI. Moreover, it allows us to evaluate the potential effectiveness of various other climate change programmes where the evaluation is commonly done by field surveys. This thereby helps to increase the credibility in the examination of the impacts of climate change at different scales in order to find key areas for better policy planning

Variation in practice patterns among specialties in the acute management of atrial fibrillation

Abstract Background Atrial fibrillation (AF) is commonly managed by a variety of specialists. Current guidelines differ in their recommendations leading to uncertainty regarding important clinical decisions. We sought to document practice pattern variation among cardiologists, emergency physicians (EP) and hospitalists at a single academic, tertiary-care center. Methods A survey was created containing seven clinical scenarios of patients presenting with AF. We analyzed respondent choices regarding rate vs rhythm control, thromboembolic treatment and hospitalization strategies. Finally, we contrasted our findings with a comparable Australasian survey to provide an international reference. Results There was a 78% response rate (124 of 158), 37% hospitalists, 31.5% cardiologists, and 31.5% EP. Most respondents chose rate over rhythm control (92.2%; 95% CI, 89.1% - 94.5%) and thromboembolic treatment (67.8%; 95% CI, 63.8% - 71.7%). Compared to both hospitalists and EPs, cardiologists were more likely to choose thromboembolic treatment for new and paroxysmal AF (adjusted OR 2.38; 95% CI, 1.05 - 5.41). They were less likely to favor hospital admission across all types of AF (adjusted OR 0.36; 95% CI, 0.17 - 0.79) but thought cardiology consultation was more important (adjusted OR 1.88, 95% CI, 0.97 - 3.64). Australasian physicians were more aggressive with rhythm control for paroxysmal AF with low CHADS2 score compared to US physicians. Conclusions Significant variation exists among specialties in the management of acute AF, likely reflecting a lack of high quality research to direct the provider. Future studies may help to standardize practice leading to decreased rates of hospitalization and overall cost.http://deepblue.lib.umich.edu/bitstream/2027.42/110777/1/12872_2015_Article_9.pd

Interesting dynamics at high mutual inclination in the framework of the Kozai problem with an eccentric perturber

We study the dynamics of the 3-D three-body problem of a small body moving under the attractions of a star and a giant planet which orbits the star on a much wider and elliptic orbit. In particular, we focus on the influence of an eccentric orbit of the outer perturber on the dynamics of a small highly inclined inner body. Our analytical study of the secular perturbations relies on the classical octupole hamiltonian expansion (third-order theory in the ratio of the semi-major axes), as third-order terms are needed to consider the secular variations of the outer perturber and potential secular resonances between the arguments of the pericenter and/or longitudes of the node of both bodies. Short-period averaging and node reduction (Laplace plane) reduce the problem to two degrees of freedom. The four-dimensional dynamics is analyzed through representative planes which identify the main equilibria of the problem. As in the circular problem (i.e. perturber on a circular orbit), the "Kozai-bifurcated" equilibria play a major role in the dynamics of an inner body on quasi-circular orbit: its eccentricity variations are very limited for mutual inclination between the orbital planes smaller than ~40^{\deg}, while they become large and chaotic for higher mutual inclination. Particular attention is also given to a region around 35^{\deg} of mutual inclination, detected numerically by Funk et al. (2011) and consisting of long-time stable and particularly low eccentric orbits of the small body. Using a 12th-order Hamiltonian expansion in eccentricities and inclinations, in particular its action-angle formulation obtained by Lie transforms in Libert & Henrard (2008), we show that this region presents an equality of two fundamental frequencies and can be regarded as a secular resonance. Our results also apply to binary star systems where a planet is revolving around one of the two stars.Comment: 12 pages, 9 figures, accepted for publication in MNRA

European Research Center for Information Systems (ERCIS):Gründungsveranstaltung Münster, 12. Oktober 2004

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A Comparison of Children’s Achievement Whose Mothers Are Employed Full Time and Those Whose Mothers Are Homemakers

This study undertook to examine the relationship between mothers\u27 employment status and the children\u27s achievement. 728 third grade students in the Bellingham Public Schools were used as subjects. The data was analyzed by two way analysis of variance and multiple correlation procedures. There was no relationship found between the mothers\u27 employment ststus and the children\u27s achievement. However, there was a relationship between fathers\u27 occupational level, family size, children\u27s intelligence, and children\u27s sex and some of the achievement tests