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12.05.2021, 10:30: Guest Talk on Neural Termination Analysis by Mirco Giacobbe

von Bolke-Hermanns, Helene

Dear all, on Wednesday, May 12, at 10:30 am, Mirco Giacobbe from the University of Oxford will give a talk on his recent work of applying neural networks to perform termination analysis. Wednesday, 12.05.2021, 10:30 am https://rwth.zoom.us/j/99669198425?pwd=NTNzTGNnYjNrQUc0ZDFTTVdiWjY4UT09 Meeting-ID: 996 6919 8425, Passcode: 878733 Everybody is welcome! Best regards Helen Bolke-Hermanns ----------------------------------------------------------------------------------------- Mirco Giacobbe (University of Oxford, UK): Neural Termination Analysis Termination analysis answers the question of whether a program always responds or, dually, never gets stuck in an infinite loop. This is unsolvable in general, yet tools that work in practice have been developed in industry and academia. The major existing methods construct termination proofs via symbolic reasoning from the source code. I will talk about a novel method for learning termination proofs from execution traces. We let neural networks fit termination witnesses over execution traces and then use satisfiability modulo theories for checking whether they generalise to all possible executions. Thanks to the ability of neural networks to generalise well, neural termination analysis succeeds over a wide variety of programs. Moreover, it is extremely simple to implement. I will talk about how we apply neural termination analysis to the termination analysis of Java programs that use data structures, to the almost-sure termination analysis of probabilistic programs, and to the stability analysis of cyber-physical systems. More information: https://www.unravel.rwth-aachen.de/go/id/nyoee

3 Jahre, 2 Monate

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Ankündigung: Informatik-Oberseminar

von Schweigler, Martin

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Mittwoch, 5. Mai 2021, 11.00 Uhr Ort: Videokonferenz (Zoom-Meeting, Information siehe unten) Referent: Martin Schweigler, M.Sc. RWTH Informatik 11 - Embedded Software Thema: Ground Surface Pattern Recognition for Enhanced Navigation Abstract: With the continuous increase in sales of electrical assisted bicycles over the last decade, the number of bicycle accidents across Europe has simultaneously grown significantly. At the same time the technology lacks on active safety systems, even though the electrification of the so-called Pedelecs would allow their development. This dissertation can be seen as the first step in the process of developing position and situation dependent active safety systems by improving the position determination accuracy of bicycle navigation systems. In the core of this work a position estimation system is developed, which uses road sections with significant surface conditions to improve the positioning accuracy of a conventional GNSS/INS. Based on the vertical accelerations acting on the moving Pedelec, the system recognizes individual spots in the road surface, e.g. manholes or potholes. To be more precise, the individual acceleration profiles that occur when passing different spots, are recorded with a smartphone and statistically modeled offline with the help of continuous hidden Markov models during the training phase. In online mode, the trained models are then used to recognize the spots by the acceleration profiles of the revisited road sections. The absolute positions of the Pedelec, relative to the global coordinates of the recognized spots, are subsequently determined by an inertial calculation of the distances traveled in the time between their detection and classification. The system thus uses statistical models to estimate the absolute position of the Pedelec and is consequently called Statistical Absolute Position Estimator, or SAPE. In the second part of this work, SAPE is used to develop a navigation system, which shows the potential of the ground surface pattern recognition. For this purpose the SAPE and GNSS position determinations are fused with an inertial navigation system using an extended Kalman filter. Since the inertial sensors provided by the chosen smartphone are not accurate enough to realize a stand-alone INS, an odometry is developed and implemented to support the navigation solution. The resulting GNSS, SAPE and odometry supported INS is finally evaluated using an RTK GNSS and its accuracy is compared to that of a conventional odometry supported GNSS/INS created with the same low-cost hardware. Es laden ein: die Dozentinnen und Dozenten der Informatik ******************************** Thema: Promotionsvortrag Martin Schweigler Uhrzeit: 05. Mai 2021 11:00 AM Amsterdam, Berlin, Stockholm, Wien Zoom-Meeting beitreten https://rwth.zoom.us/j/96325334175?pwd=R2o3TWNKYk9kS0hWN3k3UHVhblNYZz09 Meeting-ID: 963 2533 4175 Kenncode: 988764

3 Jahre, 2 Monate

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[infprof-l] Einladung Informatik-Oberseminar Philipp Weidel, December 15, 2020

von Abigail Morrison

********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Dienstag, 15. Dezember 2020, 10:00 Uhr Zoom: https://rwth.zoom.us/j/99233095930?pwd=dHhTV253V1ZYUzRtSkk1L3A1REZVUT09 Meeting-ID: 992 3309 5930 Kenncode: 626162 Referent: Philipp Weidel, Dipl. Inform. Thema: Learning and decision making in closed loop simulations of plastic spiking neural networks Abstract: To understand how animals and humans learn, form memories and make decisions is a highly relevant goal both for neuroscience and for fields that take some inspiration from neuroscience, such as machine learning and artificial intelligence. Many models of learning and decision making were developed in the fields of machine learning, artificial intelligence, and computational neuroscience. Although these models aim to describe similar mechanisms, they do not all pursue the same goal. These models can be differentiated between models aiming to reach optimal performance on a specific task (or set of tasks) and models trying to explain how animals and humans learn. Some models of the first class use biologically inspired methods (such as deep learning) but are usually not biologically realistic and are therefore not well suited to explain the function of the brain. Models in the second class focus on being biologically plausible to explain how the brain works, but often demonstrate their capability on too simplistic tasks and yield low performance on well-known tasks from machine learning. This work aims to close the gap between these two types of models. In the first part of this talk, tools are described that allow the combination of biologically plausible neural network models together with powerful toolkits known from machine learning and robotics. To this end, MUSIC, the middleware for spiking neural network simulators such as NEST and NEURON is interfaced with ROS, a middleware for robotic hardware and simulators such as Gazebo. This toolchain is extended with interfaces to reinforcement learning toolkits such as the OpenAI Gym. The second part addresses the question of how the brain can represent its environment in the neural substrate of the cortex and how a realistic model of reinforcement learning can make use of these representations. To this end, a spiking neural network model of unsupervised learning is presented which is able to learn its input projections such that it can detect and represent repeating patterns. By using an actor-critic reinforcement learning architecture driven by a realistic dopamine modulated plasticity rule the model can make use of the representations and learn a range tasks. Es laden ein: die Dozentinnen und Dozenten der Informatik -- Prof. Dr. Abigail Morrison IAS-6 / INM-6 / SimLab Neuroscience Jülich Research Center & Computer Science 3 - Software Engineering RWTH Aachen http://www.fz-juelich.de/inm/inm-6 http://www.fz-juelich.de/ias/jsc/slns http://www.se-rwth.de Office: +49 2461 61-9805 Fax # : +49 2461 61-9460 ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------ Forschungszentrum Juelich GmbH 52425 Juelich Sitz der Gesellschaft: Juelich Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Volker Rieke Geschaeftsfuehrung: Prof. Dr.-Ing. Wolfgang Marquardt (Vorsitzender), Karsten Beneke (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------

3 Jahre, 4 Monate

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Einladung: Informatik-Kolloquium Christina Büsing

von Bolke-Hermanns, Helene-Maria

********************************************************************** * * * Einladung * * * * Informatik-Kolloquium * * * ********************************************************************** Zeit: Mittwoch, 24. Februar 2021, 16:15-17:00 Uhr Ort: https://rwth.zoom.us/j/98137553896?pwd=WmVnYmhKdXhrM0hjS3NvQy84SjcwUT09 Meeting ID: 981 3755 3896 Passcode: 395762 ********************************************************************** Vortragende: Christina Büsing (RWTH) Titel: Operational Planning for Mobile Medical Units Abstract: Mobile medical units allow for an efficient medical coverage of sparsely populated, spacious areas. Unfortunately, flexibility comes at the price of a highly complex operation planning process. We developed a multi-staged optimization approach for the operation of mobile medical units combining facility location, scheduling and routing problems. To determine our vehicle routes, we have to solve a budgeted matching problem on an edge colored graph, which we refer to as budgeted colored matching problem (BCM). We show the strong NP-hardness of the BCM on bipartite graphs with uniform edge weights, costs and budgets using a reduction from (3,B2)-SAT. On special graph classes, the BCM is solvable in pseudo-polynomial time. Finally, we evaluate the usage of mobile medical units in our model region situated in the northern Eifel. To assess the quality of solutions, we developed an agent-based simulation, which models the interaction between patients and general practitioners. Es laden ein: die Dozentinnen und Dozenten der Informatik **********************************************************************

3 Jahre, 4 Monate

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Einladung: Informatik-Oberseminar Frau Sarah Suleri

von Leany Maaßen

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Donnerstag, 18. Februar 2021, 11:00-12:00 Uhr Zoom: https://rwth.zoom.us/j/92762889185?pwd=ZVdJV2o1bk13SlJCSDFRanB2TEYwUT09 Meeting-ID: 927 6288 9185 Kenncode: 725212 Referentin: Frau Sarah Suleri, M. Sc. Lehrstuhl Informatik 5 Thema: Impact of Technological Support on the Workload of Software Prototyping Abstract: Prototyping is a broadly utilized iterative technique for brainstorming, communicating, and evaluating user interface (UI) designs. This research aims to analyze this process from three aspects: traditional UI prototyping, rapid prototyping, and prototyping for accessibility. We propose three novel approaches and realize them by introducing three artifacts: 1) Eve, a sketch-based prototyping workbench that supports automation of transforming low fidelity prototypes to higher fidelities, 2) Kiwi, a UI design pattern and guidelines library to support UI design pattern-driven prototyping, 3) Personify, a persona-based UI design guidelines library for accessible UI prototyping. We evaluate the usability of these artifacts, and the results indicate good usability and learnability. Furthermore, we use NASA-TLX to study the impact of using these three novel approaches on the subjective workload experienced by the designers during the software prototyping process. This work aims to extend prior work on UI prototyping and is broadly applicable to understand the impact of using deep learning, UI design patterns, and personas on the workload of UI prototyping. 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

3 Jahre, 4 Monate

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Einladung: Informatik-Oberseminar Herr Gustavo Alejandro Aragón Cabrera

von Leany Maaßen

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Mittwoch, 24. Februar 2021, 15:00-16:00 Uhr Zoom: <https://rwth.zoom.us/j/95286199371?pwd=M3hCUWk3VER6WnE0RlZzQUFBVFMzdz09> https://rwth.zoom.us/j/95286199371?pwd=M3hCUWk3VER6WnE0RlZzQUFBVFMzdz09 Meeting-ID: 952 8619 9371 Kenncode: 424815 Referent: Herr Gustavo Alejandro Aragón Cabrera, M. Sc. Lehrstuhl Informatik 5 Thema: Extended Model Predictive Control Software Framework for Real-Time Local Management of Complex Energy Systems Abstract: Regarding the requirements of the future electrical grid due to high share of renewable distributed generation, smart energy management systems (EMS) are necessary to integrate the rapid development of ICT technologies and new sensor and actuator technologies. This thesis deals with the challenges of Model Predictive Control (MPC)-based EMS and introduces the concept of extended MPC framework that includes ICT aspects of the integration of new sensor and actuator technologies, forecasting methods, data management, flexible optimization model definition and solvers integration in consideration of user needs and deployment requirements in real systems. The extended MPC framework is validated through its deployment in three different use cases: as discrete and stochastic MPC in real test sites and linked to a power flow simulator. 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

3 Jahre, 4 Monate

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Einladung: Informatik-Oberseminar Anton Pirogov

von Anton Pirogov

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Donnerstag, 18. Februar 2021, 10:15 Uhr Ort: Zoom Videokonferenz Link: https://rwth.zoom.us/j/96519556069?pwd=MUVqbXpvZE5XVXBSdDNHZW5LMmJpQT09 Meeting-ID: 965 1955 6069 Kenncode: 482378 Referent: Anton Pirogov, M.Sc. Lehrstuhl Informatik 7 Thema: Determinization and Ambiguity of Classical and Probabilistic Büchi Automata Abstract: Büchi automata can be seen as a straight-forward generalization of ordinary NFA, adapted to handle infinite words. While they were originally introduced for applications in decidability of logics, they became a popular tool for practical applications, e.g. in automata-based approaches to model checking and synthesis problems. Being arguably both the simplest and most well-known variant in the zoo of so-called omega-automata that are considered in this setting, they serve as an intermediate representation of omega-regular specifications of verification or synthesis requirements that are usually expressed in a more declarative fashion, e.g. using linear temporal logic. Unfortunately, nondeterministic automata are not directly suitable for certain applications, whereas deterministic Büchi automata are less expressive. This problem is usually solved by either constructing deterministic automata of a different kind, or by restricting their ambiguity, i.e., the maximal number of accepting runs on some word. In both cases, the transformation is expensive, yielding an exponential blow-up of the state space in the worst case. Therefore, optimized constructions and heuristics for common special cases are useful and in demand for actual practical applications. In this talk we present a new general construction for determinization from nondeterministic Büchi to deterministic parity automata that unifies the dominant branches of previous approaches based on the Safra construction and the Muller-Schupp construction. Additionally, we sketch a number of new heuristics for determinization, some of which exploit properties of our unified construction. Apart from the classical nondeterministic and deterministic variants of automata, it is natural to consider probabilistic automata, i.e., automata that use a probability distribution on the states instead of nondeterminism to decide which state to go to next. It is known that in general, such automata are more expressive than classical automata and many decision problems are undecidable. We present subclasses of probabilistic automata that correspond to certain ambiguity classes and are not more expressive than classical automata. Es laden ein: die Dozentinnen und Dozenten der Informatik

3 Jahre, 5 Monate

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Einladung Informatik-Oberseminar Konrad Anton Fögen

von Zinner, Marion

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Mittwoch, 10. Februar 2021, 14.00 Uhr Zoom: https://rwth.zoom.us/j/91716576115?pwd=ZzUwemxXWUJkQURjQjJibmlGb3dYZz09 Meeting ID: 917 1657 6115 Passcode: 496556 Referent: Konrad Anton Fögen M.Sc. Lehr- und Forschungsgebiet Softwarekonstruktion Thema: Combinatorial Robustness Testing based on Error-Constraints Abstract: In this talk, we present an extension to combinatorial testing (CT) which is an effective specification-based test method that is based on an input parameter model (IPM). We argue that robustness is an important property of a software, which must be tested in addition to a software's functionality. This requires invalid values and invalid value combinations to be able to observe a software's reaction to them. However, the effectiveness of CT deteriorates in the presence of invalid values or invalid value combinations. This phenomenon is called invalid input masking effect and is already acknowledged in some research. It led to extensions of CT that we call combinatorial robustness testing (CRT). The objective of CRT is to improve the fault detection by avoiding invalid input masking. This is achieved by separating the testing of valid values and valid value combinations from the testing of invalid values and invalid value combinations. While CRT is a promising extension of CT, it is still insufficiently researched. For instance, in related work, IPMs are extended with additional semantic information to specify invalid values. However, invalid value combinations cannot be specified directly. Therefore, the objective of this work is to further expand the idea of CRT. The aim is to develop a new CRT test method with a modeling approach to specify invalid values and invalid value combinations equally well. This modeling approach should also be incorporated into explicit test adequate criteria and test selection strategies. Furthermore, this modeling approach shall be supported by automated techniques. First, we conduct a controlled experiment to check if CRT is necessary at all or if CT is already appropriate to test robustness. Based on the result, we continue and develop a refined t-factor fault model that incorporates robustness faults and the inherent invalid input masking effect. Next, we develop a new test method for CRT and introduce a new structure that extends the structure of IPMs. It is called robustness input parameter model (RIPM) and contains the concept of error-constraints which is an additional set of logical expressions to describe the validity of values and value combinations. With the refined t-factor fault model and the new RIPM structure, new test adequacy criteria that incorporate the additional semantic information and new test selection strategies that satisfy the test adequacy criteria are developed. The new concept of error-constraints requires additional effort in modeling. Therefore, we develop two techniques to support the modeling of them. First, we develop a technique to identify and repair inconsistencies among error-constraints. Second, we develop a technique to automatically generate error-constraints based on the conformance to another system. Last but not least, all aforementioned concepts and techniques are operationalized and integrated in a test automation framework which includes a process, an architecture, and a Java-based reference implementation. Es laden ein: die Dozentinnen und Dozenten der Informatik

3 Jahre, 5 Monate

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Einladung Informatik-Oberseminar Oliver Kautz

von Kautz, Oliver

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Mittwoch, 10. Februar 2021, 15.00 Uhr Zoom: https://rwth.zoom.us/j/96367107600?pwd=c2lMb2M1OXZXSHZFalRySUR2QTExUT09 Referent: Oliver Kautz M.Sc. Lehrstuhl Informatik 3 Thema: Model Analyses Based on Semantic Differencing and Automatic Model Repair Abstract: Models are the primary development artifacts used in model-driven software development. Therefore, models continuously evolve during the design, development, and maintenance of software systems. Thus, model differencing is an important task to understand the syntactic and semantic differences between model versions. Previous work produced general (and thus language-independent) approaches for syntactic model differencing, but only a few language-dependent approaches for semantic model differencing. Approaches combining syntactic with semantic model differencing by relating the syntactic changes of models to their semantic differences rarely exist. Previous work neglected the development of language-independent approaches abstracting from a concrete model property for detecting the syntactic elements of a model, which cause that the model does not satisfy the property. If the property encodes a requirement and the non-satisfaction represents the existence of a bug, then detecting the syntactic model elements causing the non-satisfaction of the property facilitates developers in detecting the syntactic model elements causing the bug. In this talk, we present a framework for precisely defining modeling languages, including syntax, semantics, and model evolution possibilities. We discuss syntactic and semantic model differencing. The framework is instantiated with four concrete modeling languages: Time-synchronous port automata, feature diagrams, sequence diagrams, and activity diagrams. Based on the framework for precisely defining modeling languages, we present a modeling language and property-independent framework for automatic model repairs. The framework facilitates developers in detecting the syntactic elements of a model causing that the model does not satisfy a property. Instantiating the framework with a concrete modeling language and a concrete model property enables the automatic calculation of syntactic changes that transform a model not satisfying the property to a model that satisfies the property. The framework relies on the assumption that it is possible to partition the syntactic changes applicable to each model into finitely many model-specific and property- specific equivalence classes. Es laden ein: die Dozentinnen und Dozenten der Informatik

3 Jahre, 5 Monate

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Einladung Informatik-Oberseminar Martin Serror

von Martin Serror

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Freitag, 29. Januar 2021, 14.00 Uhr Zoom: https://rwth.zoom.us/j/95719946489?pwd=S0lITm9pcW45b1k4SW5EVis2a1poQT09 Referent: Martin Serror, M.Sc. Lehrstuhl Informatik 4 Thema: On the Benefits of Cooperation for Dependable Wireless Communications Abstract: The emerging Industrial Internet-of-Things (IIoT) improves flexibility, productivity, and costs of industrial processes by connecting sensors, actuators, and controllers to each other and the Internet. On the factory floor, such interconnections increasingly rely on wireless communications, reducing deployment and maintenance costs while supporting the mobility of communication partners. The industrial domain, however, is mainly characterized by safety- and mission-critical Machine-to-Machine communication. Therefore, state-of-the-art wireless communication protocols for home and business environments, such as WLAN and Bluetooth, are not suited for the IIoT. Consequently, the IIoT requires dependable wireless communication, achieving both high reliability and low latency. A promising approach for so-called Ultra-Reliable Low-Latency Communication (URLLC) in the IIoT is cooperative diversity, since the participating stations already collaborate toward a common goal, i. e., keeping the industrial process running. There, a sending station exploits multiple independent transmission paths via cooperating relays to convey a packet to its destination reliably. In contrast to spatial diversity, this approach also works with single-input single-output transceivers. However, when considering relaying for URLLC, it is particularly challenging that all participants have to share the scarce transmission resources. Hence, in this talk, we investigate various mechanisms enabling dependable wireless communication, i. e., increasing communication reliability within a bounded low latency, where we mainly focus on the benefits of cooperative diversity. Therefore, we explore different design options for URLLC and evaluate them, leveraging the advantages of different methodological approaches. This talk thus offers valuable insights into designing communication protocols with challenging requirements. At the example of cooperation, we thoroughly retrace the development process from analysis to prototypical deployment. On the one hand, the achieved results contribute to URLLC for the IIoT; on the other hand, they provide a critical examination of the selected evaluation methodologies. Es laden ein: die Dozentinnen und Dozenten der Informatik

3 Jahre, 5 Monate

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