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

reminder: today, 10:30: Prof. Gabriele Kern-Isberner (TU Dortmund): Towards Lifted Inference: Counting Strategies for Relational Maximum Entropy Reasoning
by Bolke-Hermanns, Helen 04 Nov '20

04 Nov '20

This is a short reminder. Prof. Gabriele Kern-Isberner (TU Dortmund) Title: Towards Lifted Inference: Counting Strategies for Relational Maximum Entropy Reasoning Abstract: The principle of maximum entropy (MaxEnt) constitutes a meaningful methodology for drawing non monotonic inferences from probabilistic conditional knowledge as it satisfies some fundamental principles from commonsense reasoning. Similar to alternative approaches to probabilistic reasoning in relational settings, straightforward maximum entropy computations suffer from an exponential dependence from the size of the underlying domain which can lead to intractability in many cases. To overcome this problem, we adopt techniques from weighted first-order model counting (WFOMC) which exploit symmetries and interchangeabilities among the domain elements in order to count models of sentences more efficiently. To meet the requirements of our formalization of knowledge by conditionals, we assign a type to the counted models which captures the three-valued evaluation of the conditionals, i.e. the conditional structure of the models. We present the resulting variant of model counting which we call 'typed model counting' and discuss its benefits by means of some illustrating examples. https://www.informatik.rwth-aachen.de/go/id/jgfze Today, 10:30 https://rwth.zoom.us/j/92047949381?pwd=LzIwUW96WEM0MkRjZ01FUmhwd1I3QT09<https://www.google.com/url?q=https://rwth.zoom.us/j/92047949381?pwd%3DLzIwU…> Meeting ID: 920 4794 9381 Password: unravel Helen Bolke-Hermanns Fachgruppe Informatik RWTH Aachen University Ahornstr. 55, D-52074 Aachen Building E3, 2nd floor, Room 9218 Telefon: +49 (241) 80-21-004 Fax: +49 (241) 80-22 215 E-Mail: Helen.Bolke-Hermanns(a)Informatik.RWTH-Aachen.de<mailto:Helen.Bolke-Hermanns@Informatik.RWTH-Aachen.de> [rwth_informatik_bild_rgb]

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Einladung Informatik-Oberseminar Jan Dreier
by Jan Dreier 02 Nov '20

02 Nov '20

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Montag, 16. November 2020, 13:00 Uhr Zoom: https://rwth.zoom.us/j/94172280001?pwd=K2Z6Z1ZHbUVVdDBDbjNSWVBVUTZoZz09 Meeting ID: 941 7228 0001 Passcode: N.gdJ5 Referent: Jan Dreier, M.Sc. Lehr- und Forschungsgebiet Theoretische Informatik Thema: Two New Perspectives on Algorithmic Meta-Theorems Abstract: We present two algorithmic meta-theorems. Our first meta-theorem is an approximation scheme of the parameterized model-checking problem for the first-order counting logic FO({>0}). This logic extends first-order logic with the ability to count the number of satisfying assignments of a variable and compare it to fixed but arbitrarily large numbers. The model-checking scheme runs in linear fpt time (parameterized by formula length) on structures with bounded expansion and either gives the correct answer or says ``I do not know.'' The latter answer may only be given if small perturbations in the number-symbols of the formula could make it both satisfied and unsatisfied. As a consequence, every property expressible in FO({>0}) can be approximated in linear time on bounded expansion graph classes. A restricted set of counting properties can also be solved exactly in linear time, leading for example to an fpt algorithm for partial dominating set on bounded expansion graph classes. These results are complemented by showing that exactly solving the model-checking problem for FO({>0}) is already hard on trees of bounded depth and just slightly increasing the expressiveness of FO({>0}) makes even approximation hard on trees. Our second meta-theorem is a first-order model-checking algorithm for random graphs and complex networks. Roughly speaking, we say a random graph model is alpha-power-law-bounded if it is unclustered and the fraction of vertices with degree k is O(k^-alpha). We solve the parameterized first-order model-checking problem in almost linear fpt time on random graph models satisfying this property with alpha >= 3. This means in particular that one can solve every first-order property in almost linear expected time on these random graph models. This includes many popular models of complex networks such as preferential attachment graphs, Chung–Lu graphs, configuration graphs, and sparse Erdős–Rényi graphs. We present hardness results that show intractability for alpha < 3, assuming we allow an adversary to color the vertices of the input graph. We base our algorithms on a new structural decomposition of alpha-power-law-bounded random graphs and on new concentration bounds for the degree evolution in preferential attachment graphs. Es laden ein: die Dozentinnen und Dozenten der Informatik -- Jan Dreier RWTH Aachen University https://tcs.rwth-aachen.de/~dreier/

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04.11.2020, 10:30: Prof. Gabriele Kern-Isberner (TU Dortmund): Towards Lifted Inference: Counting Strategies for Relational Maximum Entropy Reasoning
by Bolke-Hermanns, Helen 30 Oct '20

30 Oct '20

Dear members of the Computer Science Department, You are cordially invited to the talk of Prof. Gabriele Kern-Isberner (TU Dortmund) for next week, 4.11., 10:30. Title: Towards Lifted Inference: Counting Strategies for Relational Maximum Entropy Reasoning Abstract: The principle of maximum entropy (MaxEnt) constitutes a meaningful methodology for drawing non monotonic inferences from probabilistic conditional knowledge as it satisfies some fundamental principles from commonsense reasoning. Similar to alternative approaches to probabilistic reasoning in relational settings, straightforward maximum entropy computations suffer from an exponential dependence from the size of the underlying domain which can lead to intractability in many cases. To overcome this problem, we adopt techniques from weighted first-order model counting (WFOMC) which exploit symmetries and interchangeabilities among the domain elements in order to count models of sentences more efficiently. To meet the requirements of our formalization of knowledge by conditionals, we assign a type to the counted models which captures the three-valued evaluation of the conditionals, i.e. the conditional structure of the models. We present the resulting variant of model counting which we call 'typed model counting' and discuss its benefits by means of some illustrating examples. https://www.informatik.rwth-aachen.de/go/id/jgfze Wednesday, 04.11.2020, 10:30 https://rwth.zoom.us/j/92047949381?pwd=LzIwUW96WEM0MkRjZ01FUmhwd1I3QT09<https://www.google.com/url?q=https://rwth.zoom.us/j/92047949381?pwd%3DLzIwU…> Meeting ID: 920 4794 9381 Password: unravel Best regards Helen Bolke-Hermanns Helen Bolke-Hermanns Fachgruppe Informatik RWTH Aachen University Ahornstr. 55, D-52074 Aachen Building E3, 2nd floor, Room 9218 Telefon: +49 (241) 80-21-004 Fax: +49 (241) 80-22 215 E-Mail: Helen.Bolke-Hermanns(a)Informatik.RWTH-Aachen.de<mailto:Helen.Bolke-Hermanns@Informatik.RWTH-Aachen.de> [rwth_informatik_bild_rgb]

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Ankündigung: Informatik-Oberseminar
by Obster, Mathias 26 Oct '20

26 Oct '20

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Dienstag, 10. November 2020, 14:00 Uhr Ort: Videokonferenz (Zoom-Meeting, Informationen siehe unten) Referent: Mathias Obster, M.Sc. RWTH Informatik 11 - Embedded Software Thema: Unterstützung der SPS-Programmierung durch Statische Analyse während der Programmeingabe Abstract: Durch abstrakte Interpretation und genauer durch Wertemengenanalyse lassen sich vollautomatisch Fehler in Programmcode finden, ohne diesen auszuführen. Bei Programmen für Speicherprogrammierbare Steuerungen (SPSen) ist dies für die Fehlervermeidung von besonderem Interesse, da sie im industriellen Umfeld zum Einsatz kommen. In diesem Vortrag wird ein Ansatz vorgestellt, mit dem diese Methoden bereits während der Programmeingabe, also während der Entwicklung eines SPS-Programms, zur Fehlererkennung und -vermeidung beitragen kann. Dafür wurde das Analyseframework ARCADE.PLC erweitert, sodass es Analyseergebnisse in einer Entwicklungsumgebung darstellen kann, die auch in der Industrie zum Einsatz kommt. So können dort sowohl Warnungen vor potenziell fehlerhaftem Programmverhalten als auch mögliche Variablenwerte dargestellt werden. Ein neu eingeführter inkrementeller Ansatz kann darüber hinaus den Berechnungsaufwand verringern, der sonst durch die häufige Ausführung der Analysen entsteht. Dabei wird ausgenutzt, dass sich während der Entwicklung in kurzen Zeitintervallen üblicherweise nur kleine Änderungen für das Gesamtprogramm ergeben. Für die Bereitstellung einer integrierten Lösung für den Anwender wurden die Konzepte und eine Erweiterung für eine Entwicklungsumgebung für SPS-Programme prototypisch umgesetzt und im Rahmen einer kleinen Nutzerstudie evaluiert. Dabei stand die Frage im Mittelpunkt, ob Programmierer während der Eingabe und Bearbeitung eines SPS-Programms von Ergebnissen der Statischen Analyse profitieren können. Es laden ein: die Dozentinnen und Dozenten der Informatik ******************************** Thema: [Promotion Mathias Obster] Vortrag Uhrzeit: 10.Nov.2020 02:00 PM Amsterdam, Berlin, Rom, Stockholm, Wien Zoom-Meeting beitreten https://rwth.zoom.us/j/98589897540?pwd=OWZidEpuU1N5bjA5UFIxcFhNUEJidz09 Meeting-ID: 985 8989 7540 Kenncode: 111012

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21.10., 10.00: Prof. Michael Schaub, RWTH Aachen: Learning from signals on graphs with unobserved edges
by Bolke-Hermanns, Helen 18 Oct '20

18 Oct '20

Dear members of the Computer Science Department, You are cordially invited to the talk of Prof. Michael Schaub, RWTH Aachen. Title: Learning from signals on graphs with unobserved edges Abstract: In many applications we are confronted with the following system identification scenario: we observe a dynamical process that describes the state of a system at particular times. Based on these observations we want to infer the (dynamical) interactions between the entities we observe. In the context of a distributed system, this typically corresponds to a "network identification" task: find the (weighted) edges of the graph of interconnections. However, often the number of samples we can obtain from such a process are far too few to identify the edges of the network exactly. Can we still reliably infer some aspects of the underlying system? Motivated by this question we consider the following identification problem: instead of trying to infer the exact network, we aim to recover a (low-dimensional) statistical model of the network based on the observed signals on the nodes. More concretely, here we focus on observations that consist of snapshots of a diffusive process that evolves over the unknown network. We model the (unobserved) network as generated from an independent draw from a latent stochastic blockmodel (SBM), and our goal is to infer both the partition of the nodes into blocks, as well as the parameters of this SBM. We present simple spectral algorithms that provably solve the partition and parameter inference problems with high-accuracy. We further discuss some possible variations and extensions of this problem setup. https://www.informatik.rwth-aachen.de/go/id/jgfsd Wednesday, 21.10.2020, 10:00 Join Zoom Meeting https://rwth.zoom.us/j/92047949381?pwd=LzIwUW96WEM0MkRjZ01FUmhwd1I3QT09<https://www.google.com/url?q=https://rwth.zoom.us/j/92047949381?pwd%3DLzIwU…> Meeting ID: 920 4794 9381 Password: unravel Best regards Helen Bolke-Hermanns Helen Bolke-Hermanns Fachgruppe Informatik RWTH Aachen University Ahornstr. 55, D-52074 Aachen Building E3, 2nd floor, Room 9218 Telefon: +49 (241) 80-21-004 Fax: +49 (241) 80-22 215 E-Mail: Helen.Bolke-Hermanns(a)Informatik.RWTH-Aachen.de<mailto:Helen.Bolke-Hermanns@Informatik.RWTH-Aachen.de> [rwth_informatik_bild_rgb]

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7.10., 17.00: Guy Van den Broeck, UCLA: From Probabilistic Circuits to Probabilistic Programs and Back
by Bolke-Hermanns, Helen 05 Oct '20

05 Oct '20

Dear members of the Computer Science Department, You are cordially invited to the talk of the UnRAVeL guest Guy Van den Broeck, UCLA Title: From Probabilistic Circuits to Probabilistic Programs and Back Abstract: Probabilistic graphical models are a rich staple of probabilistic AI. However, they make a very specific choice of abstraction: probability distributions are represented by their variable-level (in)dependencies. In this talk I present some recent work on probabilistic models that go beyond classical PGMs, and make a radically different choice of abstraction; one that is computational. Concretely, I will discuss two classes of models: probabilistic circuits and probabilistic programs. Probabilistic circuits represent distributions through the computation graph of probabilistic inference. They move beyond PGMs by guaranteeing tractable inference for certain classes of queries. Probabilistic programs represent distributions through higher-level primitives of computation: iteration, branching, and procedural abstraction. They move beyond PGMs by looking "inside" of the dependencies. Finally, I will illustrate how these two computational abstractions are themselves closely related, by showing how the Dice probabilistic programming language compiles probabilistic programs into probabilistic circuits for inference. Wednesday, Oct. 7th, 5.00 pm The talk will take place as a zoom-session: https://rwth.zoom.us/j/92047949381?pwd=LzIwUW96WEM0MkRjZ01FUmhwd1I3QT09<https://www.google.com/url?q=https://rwth.zoom.us/j/92047949381?pwd%3DLzIwU…> Meeting ID: 920 4794 9381, Password: unravel Best regards Helen Bolke-Hermanns Helen Bolke-Hermanns Fachgruppe Informatik RWTH Aachen University Ahornstr. 55, D-52074 Aachen Building E3, 2nd floor, Room 9218 Telefon: +49 (241) 80-21-004 Fax: +49 (241) 80-22 215 E-Mail: Helen.Bolke-Hermanns(a)Informatik.RWTH-Aachen.de<mailto:Helen.Bolke-Hermanns@Informatik.RWTH-Aachen.de> [rwth_informatik_bild_rgb]

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Einladung Informatik-Oberseminar Dr. Andreas Wortmann, 03. November 2020, 12:30 Uhr
by Bernhard Rumpe 30 Sep '20

30 Sep '20

********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * *********************************************************************** Zeit: Dienstag, 03. November 2020, 12:30 Uhr Zoom: https://rwth.zoom.us/j/92659511051?pwd=TmVibnlCNUdYZzlZSW52eCs0V2RjQT09 Referent: Dr. Andreas Wortmann Thema: Model-Driven Architecture and Behavior of Cyber-Physical Systems Vorstellung des Habilitationsvorhabens. Abstract: Systems engineering has produced striking results in many domains. Researchers and practitioners have devised concepts, methods, tools that autonomously move vehicles, enable doctors to conduct remote surgeries across continents, and sent astronauts into space. All of these cyber-physical systems are driven by software whose complexity increases tremendously. Overcompensating this growth in software and systems complexity demands novel methods that increase the abstraction in systems engineering, advance automation, and facilitate the integration of domain expert solutions. Model-based systems engineering aims to address this complexity by advancing systems engineering from its contemporary document-based processes to sophisticated model-based processes. In the latter, abstract models serve as means for systems design, communication, documentation, and basis for implementation. But to overcompensate the growth in complexity, using models as secondary artifacts is insufficient. Comprehensive research in software engineering has led to recognizing that model-driven processes, in which models are the primary engineering artifacts, can significantly improve abstraction, automation, and domain-specific modeling to address the increasing complexity in systems engineering. Yet, model-based systems engineering focuses on informal models that are hardly accessible to meaningful automation and overly generic. This thesis summarizes 14 selected publications of a research program towards a model-driven systems engineering that operates on domain-specific modeling languages, supports sophisticated modeling methods, and enables the systematic operation of cyber-physical systems. The results of this research program cover four substantial challenges towards the model-driven engineering of cyber-physical systems: First, it contributes to understanding the use of models and modeling languages for cyber-physical systems through two comprehensive literature studies on modeling for cyber-physical systems in Industry 4.0 and mobile robotics. The studies surveyed over 3.000 publications each and produced insights into requirements for the efficient model-driven engineering and operations of cyber-physical systems in both domains. Second, it conduces novel foundations for the efficient engineering of domain-specific modeling languages based on the requirements identified in both studies. These foundations introduce innovative notions of language components and their composition upon which families of domain-specific modeling languages can be created systematically efficiently. Third, it leverages these foundations to produce modeling languages to describe functional architectures and geometric-physical architectures of cyber-physical systems that support unprecedented automated modeling methods, including tracing, decomposition, and semantic differencing, to facilitate modeling, maintaining, and evolving these architectures. Fourth, it exploits the novel language engineering foundations and the unprecedented automated modeling methods to alleviate the systematic operation of cyber-physical systems with digital twins that represent and optimize the observed systems. Hence, this research program forges a bridge from observations on modeling cyber-physical systems, over software language engineering and modeling methods, to their operation that supports researchers and practitioners to advance from the contemporary document-based engineering of cyber-physical systems to their systematic model-driven engineering. Vita: Andreas Wortmann is a tenured research associate at the Chair for Software Engineering at RWTH Aachen University. There, he leads a team on model-driven systems engineering, coordinates a workstream of the Internet of Production excellence cluster, and advises the Center for Systems Engineering. He conducts research in model-driven software and systems engineering, formal methods in software engineering, and software language engineering, which is documented in over 70 publications. Moreover, he has chaired and organized various international conferences and workshops, serves on the board of the European Association for Programming Languages and Systems (EAPLS), and co-chairs the working group on model-based systems engineering of the German INCOSE chapter GfSE. Es laden ein: die Dozentinnen und Dozenten der Informatik -- ---------------------------------------------------------------- Prof. Dr. Bernhard Rumpe | http://www.se-rwth.de Lehrstuhl Software Engineering | Informatik 3 Ahornstr. 55, 52074 Aachen, Germany | RWTH Aachen University Phone ++49 241 80-21301 / Fax -22218 |

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Einladung: Informatik Oberseminar Markus Hoehnerbach
by Markus Hoehnerbach 16 Sep '20

16 Sep '20

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Dienstag, 22. September 2020, 16.00 Uhr Ort: Videokonferenz (Zoom-Meeting, Informationen siehe unten) 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 ******************************** Thema: Dissertation M. Höhnerbach Uhrzeit: 22.Sep.2020 03:45 PM Paris Zoom-Meeting beitreten https://rwth.zoom.us/j/98920238040?pwd=Q3F1OStEcklpcDV1Vk5IWEp0cFFEQT09 Meeting-ID: 989 2023 8040 Kenncode: 668020

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Einladung Informatik-Oberseminar Jan Rüth
by Jan Rüth 06 Aug '20

06 Aug '20

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Freitag, 14. August 2020, 13.00 Uhr Zoom: https://rwth.zoom.us/j/94972202308?pwd=Y1o5cnBQYTYxdS9tYldaN0piQkozQT09 Referent: Jan Rüth, M.Sc. Lehrstuhl Informatik 4 Thema: Measuring the Evolution of the Internet in the Age of Giants Abstract: The Internet has evolved into an essential cornerstone of modern life. At its core, it is seemingly still powered by protocols developed in the late 1980s. Since then, the Internet has experienced a colossal visible evolution, e.g., from delivering small text files over dynamic websites to highly interactive and bulky content that define whole economic sectors. Notwithstanding, it is hard to believe that this change demanded no technological evolution, and in fact, research and industry have worked on many mechanisms and improvements to the core protocols. Today, we see Internet giants such as Google, Facebook, or Akamai controlling clients, servers, and networks driving these changes. Still, research has shown that these innovations often remain hard to deploy in practice as the Internet has condensed to supporting only a small set of protocols and parts of their features today. In this talk, we present novel Internet measurement methodologies to gain an understanding of how the Internet has evolved from textbook knowledge, how it deviates from standardized practices, and how these discovered discrepancies affect Internet operation. To this end, we recognize the critical role of Internet giants and specifically investigate their impact on core Internet technologies. In this presentation, we focus on the transport layer and examine TCP initial congestion window configurations, Congestion Control fairness, and QUIC as a new Internet transport. Lastly, we present how WebAssembly is largely abused for cryptocurrency mining in the Web today. Our contributions demonstrate that Internet giants coin practical Internet evolution. While they are keen to standardize their innovations, their configurations are often a well-kept secret. Their market dominance challenges the innovation of others, but even they are not immune to an abuse of their technology. Es laden ein: die Dozentinnen und Dozenten der Informatik

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Einladung: Informatik-Oberseminar Frau Rihan Hai
by Leany Maaßen 30 Jun '20

30 Jun '20

+********************************************************************** * * * 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

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