- informatik-vortraege - lists.rwth-aachen.de

Einladung: Informatik-Oberseminar Frau Rihan Hai

von Leany Maaßen

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Montag, 13. Juli 2020, 16:00 Uhr Zoom: <https://rwth.zoom.us/j/95676455814?pwd=NUEvVnFVNEVLSjFsTWY2OEw2VWhrdz09> https://rwth.zoom.us/j/95676455814?pwd=NUEvVnFVNEVLSjFsTWY2OEw2VWhrdz09 Meeting-ID: 956 7645 5814 Passwort: 302988 Referentin: M.Eng. Rihan Hai Lehrstuhl Informatik 5 Thema: Data integration and Metadata Management in Data Lakes Abstract: Although big data has been discussed for some years, it still has many research challenges, such as the variety of data. Non-integrated data management systems with heterogeneous schemas, query languages, and data models result in information silos. As traditional 'schema-on-write' approaches such as data warehouses cannot solve the challenges to efficiently integrate, access, and query the information silos, data lake systems have been proposed as a solution to this problem. Data lakes are repositories storing raw data in its original format and providing a common access interface. In this thesis, we present a comprehensive and flexible data lake architecture and the prototype system Constance. First, we propose a native mapping representation to capture the hierarchical structures of nested mappings and efficient mapping generation algorithms. Second, to provide a unified querying interface, we design a novel query rewriting engine that combines logical methods for data integration based on declarative mappings with the big data processing system Apache Spark. Third, we also study the formalism of the generated schema mappings as dependencies. Our algorithmic approach transforms schema mappings expressed in second-order logic to their logically equivalent first-order forms. Finally, we introduce clustering-based algorithms to discover relaxed functional dependencies, which enrich the metadata and improve data quality in the data lake. Es laden ein: die Dozentinnen und Dozenten der Informatik _______________________________ Leany Maaßen RWTH Aachen University Lehrstuhl Informatik 5, LuFG Informatik 5 Prof. Dr. Stefan Decker, Prof. Dr. Matthias Jarke, Prof. Gerhard Lakemeyer Ph.D. Ahornstrasse 55 D-52074 Aachen Tel: 0241-80-21509 Fax: 0241-80-22321 E-Mail: maassen(a)dbis.rwth-aachen.de

4 Jahre

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Einladung: Informatik-Oberseminar Herr Markus Beutel

von Leany Maaßen

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Dienstag, 30. Juni 2020, 14.00-15.00 Uhr Zoom: <https://rwth.zoom.us/j/95676455814?pwd=NUEvVnFVNEVLSjFsTWY2OEw2VWhrdz09> https://rwth.zoom.us/j/95676455814?pwd=NUEvVnFVNEVLSjFsTWY2OEw2VWhrdz09 Meeting-ID: 956 7645 5814 Passwort: 302988 Referent: Dipl.-Kfm. Markus Beutel Thema: End-to-End-Integration von komplementären Mobilitätsdienstleistungen durch unternehmensübergreifende Anbieterkooperation Abstract: Reisenden steht heutzutage eine Vielzahl unterschiedlicher Verkehrsmodi zur Verfügung. Dabei können sich viele Fortbewegungsmittel aufgrund individueller Charakteristika gegenseitig ergänzen, anstatt sich zu substituieren. Durch eine zumindest in Teilen segmentierte und anbieterspezifische Bereitstellung von Verkehrsdienstleistungen können beispielsweise ökonomische und ökologische Ineffizienzen entstehen. Im Zentrum einer vollständigen Digitalisierung und Integration heterogener Mobilitätsdienstleistungen sollte daher der ganzheitliche Dienstleistungsprozess, über die gesamte Servicekette hinweg, in den Mittelpunkt gestellt werden. Das übergeordnete Ziel dieser Arbeit besteht in der Erforschung einer integrierten Bereitstellung sich ergänzender Mobilitätsdienstleistungen, über Unternehmensgrenzen hinweg. Ausgangspunkt dieser Arbeit bildet die Untersuchung einer spezifischen Mobilitätsplattform im Hinblick auf verschiedene Integrationsfaktoren. Auf Basis einer umfassenden Analyse von Mobilitätsplattformen und in Verbindung mit der Beschreibung eines organisatorischen Rollenmodells werden daraufhin mögliche Anbieterkooperationsszenarien beschrieben. Um die unternehmensübergreifende Integration auf Prozessebene zu betrachten, wird schließlich ein Ansatz zur Erweiterung eines Softwarewerkzeugs zur Fusion von Geschäftsprozessmodellen evaluiert. Es laden ein: die Dozentinnen und Dozenten der Informatik _______________________________ Leany Maaßen RWTH Aachen University Lehrstuhl Informatik 5, LuFG Informatik 5 Prof. Dr. Stefan Decker, Prof. Dr. Matthias Jarke, Prof. Gerhard Lakemeyer Ph.D. Ahornstrasse 55 D-52074 Aachen Tel: 0241-80-21509 Fax: 0241-80-22321 E-Mail: maassen(a)dbis.rwth-aachen.de

4 Jahre, 1 Monat

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Einladung: Informatik-Oberseminar Herr István Koren

von Leany Maaßen

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Freitag, 08. Mai 2020, 11.00 Uhr Zoom: https://rwth.zoom.us/j/94637532047?pwd=aVlweVRLdGU0OWNjdEh4TmJhSktrUT09 Referent: Dipl.-Medieninf. István Koren Lehrstuhl Informatik 5 Thema: DevOpsUse: Community-Driven Continuous Innovation of Web Information Infrastructures Abstract: The steady evolution of the Web over the last thirty years was shaped by an interplay of new technologies and innovative applications. The current challenges are caused by the ongoing digital transformation of whole societies. In Industry 4.0 for example, these are changing workplace settings and the adoption of the Internet of Things. Inhibiting the demanded fast innovation cycles, this may create a disruptive and unstable environment in which the requirements of heterogeneous professional communities need to be addressed. Information systems infrastructure, while only partially visible and thus hard to grasp, has a strong influence on practices in professional communities. Therefore, our aim is to stabilize the dichotomies apparent in the Web by means of an agile information systems development methodology. It supports the evolution of infrastructure through community-driven and model-based technologies to guide it on a sustainable path of continuous innovation. Agile development practices in software engineering, in particular the already established DevOps approach, promote stronger cooperation between development and operating teams. Our DevOpsUse methodology additionally fosters a stronger involvement of end user communities in software development processes by including them in the process of infrastructuring, i.e. the appropriation of infrastructure during its usage. The developed DevOpsUse methodology has been successfully validated by the transitions between three generations of technologies: near real-time peer-to-peer Web architectures, edge computing, and the Internet of Things. In particular, we were able to demonstrate our methodologys capabilities through longitudinal studies in several large-scale international digitalization projects. Beyond Web information systems, the framework and its open source tools are applicable in further innovative areas like mixed reality. Its broad adaptability testifies that DevOpsUse has the potential to unlock sustainable innovation capabilities. Es laden ein: die Dozentinnen und Dozenten der Informatik _______________________________ Leany Maaßen RWTH Aachen University Lehrstuhl Informatik 5, LuFG Informatik 5 Prof. Dr. Stefan Decker, Prof. Dr. Matthias Jarke, Prof. Gerhard Lakemeyer Ph.D. Ahornstrasse 55 D-52074 Aachen Tel: 0241-80-21509 Fax: 0241-80-22321 E-Mail: maassen(a)dbis.rwth-aachen.de

4 Jahre, 2 Monate

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Einladung: Informatik-Oberseminar Kazuki Irie

von Sekretariat I6

****************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * ******************************************************* Zeit: Dienstag, 05. Mai 2020, 14.00 Uhr Zoom: https://us02web.zoom.us/j/84813327259?pwd=Y2NydlRMRzE1dkpkcmpERkFwMWZYZz09 Referent: Kazuki Irie, M.Sc. Thema: Advancing Neural Language Modeling in Automatic Speech Recognition// Abstract: Statistical language modeling is one of the fundamental problems in natural language processing. In the recent years, language modeling has seen great advances by active research and engineering efforts in applying artificial neural networks, especially those which are recurrent. The application of neural language models to speech recognition has now become well established and ubiquitous. Despite this impression of some degree of maturity, we claim that the full potential of the neural network based language modeling is yet to be explored. In this thesis, we further advance neural language modeling in automatic speech recognition, by investigating a number of new perspectives. From the architectural view point, we investigate the newly proposed Transformer neural networks for language modeling application. The original model architecture proposed for machine translation is studied and modified to accommodate the specific task of language modeling. Particularly deep models with about one hundred layers are developed. We present an in-depth comparison with the state-of-the-art recurrent neural network language models based on the long short-term memory. While scaling up language modeling to larger scale datasets, the diversity of the data emerges as an opportunity and a challenge. The current state-of-the-art neural language modeling lacks a mechanism of handling diverse data from different domains for a single model to perform well across different domains. In this context, we introduce domain robust language modeling with neural networks, and propose two solutions. As a first solution, we propose a new type of adaptive mixture of experts model which is fully based on neural networks. In the second approach, we investigate knowledge distillation from multiple domain expert models, as a solution to the large model size problem seen in the first approach. Methods for practical applications of knowledge distillation to large vocabulary language modeling are proposed, and studied to a large extent. Finally, we investigate the potential of neural language models to leverage long-span cross-sentence contexts for cross-utterance speech recognition. The appropriate training method for such a scenario is under-explored in the existing works. We carry out systematic comparisons of the training methods, allowing us to achieve improvements in cross-utterance speech recognition. In the same context, we study the sequence length robustness for both recurrent neural networks based on the long short-term memory and Transformers, because such a robustness is one of the fundamental properties we wish to have, in neural networks with the ability to handle variable length contexts. Throughout the thesis, we tackle these problems through novel perspectives of neural language modeling, while keeping the traditional spirit of language modeling in speech recognition. Es laden ein: die Dozentinnen und Dozenten der Informatik -- -- Stephanie Jansen Faculty of Mathematics, Computer Science and Natural Sciences HLTPR - Human Language Technology and Pattern Recognition RWTH Aachen University Ahornstraße 55 D-52074 Aachen Tel. Frau Jansen: +49 241 80-216 06 Tel. Frau Andersen: +49 241 80-216 01 Fax: +49 241 80-22219 sek(a)i6.informatik.rwth-aachen.de www.hltpr.rwth-aachen.de Tel: +49 241 80-216 01/06 Fax: +49 241 80-22219 sek(a)i6.informatik.rwth-aachen.de www.hltpr.rwth-aachen.de

4 Jahre, 3 Monate

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Vortrag Matthias Wichtlhuber (DeCIX) 21.4. 11:00

von Johannes Krude

Hallo, Matthias Wichtlhuber vom DeCIX hält nächsten Dienstag für die Aachener Informatik einen Vortrag über Gegenmaßnahmen zu Distributed-Denial-of-Service (DDoS) attacks am DeCIX und über die Traffic Veränderungen am DeCIX aufgrund des COVID-19 lockdowns. Wann: Dienstag 24.4. 11:00 Zoom Meeting ID: 916 2538 0906, Password: 091338 https://rwth.zoom.us/j/91625380906?pwd=cEJCSk01VkVEUUpTSjgzYTlnNk5Odz09 Abstract des Vortrags: We will start with a short introduction of Internet Exchange Points (IXPs) and their operations. With this background, we will discuss the topic of Distributed-Denial-of-Service (DDoS) attacks at IXPs. We present results of a recent measurement study of DDoS-for-hire Websites (Booters) and the traffic effects of a seizure operation of 15 Booter websites by the FBI in late 2018 [1]. Subsequently, we introduce the concept of Advanced Blackholing, a published and operational mechanism designed by the DE-CIX research team to defend IXP links against DDoS attacks [2]. Due to the current COVID-19 situation, we will close the presentation by showing some preliminary results on the traffic shifts caused by nation-wide lockdowns in several countries. Über Matthias Wichtlhuber: Matthias Wichtlhuber holds a Diploma in Information Systems from Universität Mannheim and a Ph. D. from Technische Universität Darmstadt. His Ph. D. thesis focused on optimizing content delivery on the Internet. During his Ph. D. he worked on numerous EU and nationally funded research projects as well as industrial projects. After his studies, he joined DE-CIX, the operator of the largest Internet Exchange Point (IXP) in the world in Frankfurt. He is a member of the DE-CIX research team and works on product development, system security, future network architectures for Internet exchange points, and large-scale network data analysis. [1] Kopp, D., Wichtlhuber, M., Poese, I., Santanna, J., Hohlfeld, O., & Dietzel, C.: “DDoS Hide & Seek: On the Effectiveness of a Booter Services Takedown”, ACM IMC, 2019. [2] Dietzel, C., Wichtlhuber, M., Smaragdakis, G., & Feldmann, A.: “Stellar: Network Attack Mitigation using Advanced Blackholing”, ACM CoNEXT, 2018.

4 Jahre, 3 Monate

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Einladung: Informatik Oberseminar Markus Hoehnerbach

von Markus Hoehnerbach

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Montag, 23. Maerz 2020, 10.00 Uhr Ort: Raum 115, Rogowski-Gebaeude, Referent: Markus Hoehnerbach M.Sc. High-Performance and Automatic Computing Thema: A Framework for the Vectorization of Molecular Dynamics Kernels Abstract: We introduce a domain-specific language (DSL) for many-body potentials, which are used in molecular dynamics (MD) simulations in the area of materials science. We also introduce a compiler to translate the DSL into high-performance code suitable for modern supercomputers. We begin by studying ways to speedup up potentials on supercomputers using two case studies: The Tersoff and the AIREBO potentials. In both case studies, we identify a number of optimizations, both domain-specific and general, to achieve speedups of up to 5x; we also introduce a method to keep the resulting code performance portable. During the AIREBO case study, we also discover that the existing code contains a number of errors. This experience motivates us to include the derivation step, the most error-prone step in manual optimization, in our automation effort. After having identified beneficial optimization techniques, we create a ``potential compiler'', short PotC, which generates fully-usable performance-portable potential implementations from specifications written in our DSL. DSL code is significantly shorter (20x to 30x) than a manual code, reducing both manual work and opportunities to introduce bugs. We present performance results on five different platforms: Three CPU platforms (Broadwell, Knights Landing, and Skylake) and two GPU platforms (Pascal and Volta). While the performance in some cases remains far below that of hand-written code, it also manages to match or exceed manually written implementations in other cases. For these cases, we achieve speedups of up to 9x compared to non-vectorized code. Es laden ein: die Dozentinnen und Dozenten der Informatik

4 Jahre, 4 Monate

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Einladung: Informatik-Oberseminar Sandra Kiefer

von Sandra Kiefer

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Montag, 16. März 2020, 10:45 Uhr Ort: Raum 9222, Gebäude E3, Ahornstr. 55 Referentin: Sandra Kiefer, M.Sc. Lehrstuhl Informatik 7 Thema: Power and Limits of the Weisfeiler-Leman Algorithm Abstract: The Weisfeiler-Leman (WL) algorithm is a fundamental combinatorial procedure used to classify graphs and other relational structures. Through its connections to many research areas such as logics and machine learning, surprising characterisations of the algorithm have been discovered. We combine some of these to obtain powerful proof techniques. For every k, the k-dimensional version of the algorithm (k-WL) iteratively computes a stable colouring of the vertex k-tuples of the input graph. The larger k, the more powerful k-WL becomes with respect to the distinguishability of graphs. We have studied two central parameters of the algorithm, its number of iterations until stabilisation and its dimension. The results enable a precise understanding of 1-WL, namely we have determined its iteration number and have developed a complete characterisation of the graphs for which 1-WL correctly decides isomorphism. In higher dimensions, however, the situation is different. For example, it is often not clear at all how to decide if k-WL distinguishes two particular graphs. By our results, 3-WL identifies every planar graph, which drastically improves upon all previously known bounds. Generalising this insight, we obtain the first explicit parametrisation of the WL dimension by the Euler genus of the input graph. Es laden ein: die Dozentinnen und Dozenten der Informatik

4 Jahre, 4 Monate

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Einladung: Informatik-Oberseminar Gereon Kremer

von Gereon Kremer

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Donnerstag, 12. März 2020, 10:45 Uhr Ort: Raum 9222, Gebäude E3, Ahornstr. 55 Referent: Gereon Kremer, M.Sc. Theory of Hybrid Systems Thema: Cylindrical Algebraic Decomposition for Nonlinear Arithmetic Problems Abstract: We explore the usage of the cylindrical algebraic decomposition method for satisfiability modulo theories solving, both theoretically and experimentally. This method is commonly understood as an almost atomic procedure that gathers information about an algebraic problem and then allows to answer all kinds of questions about this algebraic problem afterwards. We essentially break up this method into smaller components that we can then process in varying order to derive the particular piece of information – whether the problem is satisfiable or unsatisfiable – allowing to avoid some amount of computations. As this method often exhibits doubly exponential running time, these savings can be very significant in practice. We then turn to an alternative approach to satisfiability modulo theories solving commonly called model-constructing satisfiability calculus. The core idea of this framework is to integrate the theory reasoning, in particular the construction of a theory model, very tightly with the Boolean reasoning. The main theory reasoning engine is again based on the cylindrical algebraic decomposition method, though we focus more on the overall framework here. Es laden ein: die Dozentinnen und Dozenten der Informatik -- Gereon Kremer Lehr- und Forschungsgebiet Theorie Hybrider Systeme RWTH Aachen Tel: +49 241 80 21243

4 Jahre, 4 Monate

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Einladung Informatik-Oberseminar Christian Corsten

von Corsten, Christian

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Dienstag, 10. März 2020, 9.30 Uhr Ort: Raum 2222, Ahornstr. 55 (Informatikgebäude, Hauptbau; Seminarraum i10) Referent: Christian Corsten, M.Sc. Lehrstuhl Informatik 10 Thema: Use the Force: How Force Touch Improves Input on Handheld Touchscreens Abstract: Handheld devices, such as smartphones, have become essential tools in our everyday life. We use them, e.g., to contact people, browse the web, or take pictures. For whatever use, to interact with the handheld device, we hold it with one or two hands and touch with our fingers on the built-in touchscreen. However, this interaction is often constrained to simple contact between the finger and the flat display glass, although touch offers further, richer properties. One such rich property is the intensity of a touch, i.e., its force, that the user applies with every tap to the touchscreen. Incorporating this property into the user’s interaction with the handheld device enables her to become more expressive with every single touch. In this thesis, we present a series of interaction techniques that take advantage of force touch input to make handheld interaction more efficient: When holding the device with two hands in landscape orientation, most of the fingers are unavailable for interaction, since they rest at the back of the device (BoD), holding it in place. Using BoD force input, we can make efficient use of these fingers without sacrificing stability of the device grip. Our technique, BackXPress, enables quick access to shortcuts and menus to augment users’ touch interaction with the frontal screen. For single-handed device use, users can only use their thumb to interact with the frontal touchscreen but cannot reach everywhere without re-grasping the device. Our virtual thumb extension, ForceRay, lets the user cast a ray at unreachable targets and control a cursor on that ray that moves closer to these targets the more force is applied. The technique is ergonomic for the thumb and enables users to maintain a steady device grip. Targets located at the screen edges, like menus and navigation buttons, are acquired quickly. Selection of values from long ordered lists, such as picking a date or time, can also be sped up when using force input. With our Force Picker, users scroll through the value range at various speeds, with the speed being coupled to the force exerted by the thumb. Prior rolling of the thumb to the left or right sets the scrolling direction. Compared to touch-based pickers, our Force Picker not only makes selection faster, but also only consumes little screen space since the gesture footprint for force input is much smaller. While controlling force via fingers requires practice, we show that with training and algorithmic optimizations, users become quickly familiar with force input and gain the benefits of the added expressiveness for handheld interaction. Es laden ein: die Dozentinnen und Dozenten der Informatik

4 Jahre, 4 Monate

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Einladung: Informatik Oberseminar Daniel Zielasko (Raumänderung!)

von Daniel Zielasko

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Freitag, 21. Februar 2020, 9.00 Uhr Ort: IT Center Erweiterungsbau, Kopernikusstraße 6, S003 Referent: Daniel Zielasko, M.Sc. Lehrstuhl Informatik 12 Thema: DeskVR: Seamless Integration of Virtual Reality into Desk-based Data Analysis Workflows Abstract: In this work, we are looking into the possibilities and unique challenges virtual reality today offers for (office) desk-based scenarios, as they are ubiquitous in data analysis. We characterize the scenario, introduce the term deskVR, and name the technical challenges that come with it. Furthermore, we tackle specific demands in two pillars of interaction in virtual reality, selection & manipulation, and navigation. Then, we investigate passive and active methods to prevent and reduce cybersickness, as for us, tackling cybersickness is one if not the most critical tasks that have to be solved to integrate virtual reality into everyday life successfully. Finally, we apply the methods and findings made in this thesis to a prototypical application framework for immersive 3D graph exploration, serving as proof of concept for the integrability of virtual reality into desk-based working scenarios. In the graph visualization domain, we then also propose new vertex positioning and edge bundling methods that address challenges arising with the performed up-projection into 3D interactive space. Es laden ein: die Dozentinnen und Dozenten der Informatik

4 Jahre, 5 Monate

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