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

Survey Lecture - Highlights of UnRAVeL
by Kassing, Jan-Christoph 08 May '25

08 May '25

Dear all, We invite you to the next UnRAVeL survey lecture talk Today 12:30 to 14:00, Computer Science Center, Building E2, ground floor, B-IT room 5053.2, given by Nils Nießen about "Uncertainty in Railways“! -------------------- Titel: Uncertainty in Railways Abstract: Uncertainties and randomness play a major role on the railway and contribute to the operational performance. We provide an overview of where uncertainties occur in the railway system and how they can be modelled. Subsequently, we present methods and algorithms that were developed within the framework of UnRAVeL. Finally, we explain why the railways are still delayed. -------------------- Part of the programme of the research training group UnRAVeL is a series of lectures on the topics of UnRAVeL’s research thrusts algorithms and complexity, verification, logic and languages, and their application scenarios. Each lecture is given by one of the researchers involved in UnRAVeL. This years topic is "Highlights of UnRAVeL!". As UnRAVeL nears its conclusion, we take this opportunity to reflect on seven years of excellent research. Through nine talks, we invite you to experience the scientific highlights of our RTG, along with its numerous successes, developments, and collaborations. All interested doctoral researchers and master students are invited to attend the UnRAVeL lecture series 2025 and engage in discussions with researchers and doctoral students. The overall remaining schedule is as following: 08.05.2025 - Nils Nießen - Uncertainty in Railways 15.05.2025 - Joost-Pieter Katoen - Verification Conquers Fault Tree Analysis: From Theory to Start-Up 22.05.2025 - Britta Peis - On Train Routing and Length-bounded Disjoint Paths 26.06.2025 - Michael Schaub - Oversmoothing in Graph Neural Networks 03.07.2025 - Sebastian Trimpe - Uncertainty in Learning and Control 10.07.2025 - Christopher Morris - Exploring the Power of Graph Neural Networks in Solving Optimization Problems 17.07.2025 - Christina Büsing - Dealing with Uncertainty Inspired by Health Care – a Robust Optimization Approach Kind regards, Jan-Christoph for the organisation committee

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Einladung Informatik-Oberseminar
by Martin Bellgardt 29 Apr '25

29 Apr '25

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Mittwoch, 30. April, 13.00 Uhr Ort: Seminarraum 003, Kopernikusstraße 6 Referent: Martin Bellgardt M.Sc. Lehr- und Forschungsgebiet Informatik 12 Thema: Increasing Immersion in Machine Learning Pipelines for Mechanical Engineering Abstract: Machine learning has become a vital tool in the toolbox of any discipline that regularly interacts with data. This holds especially true for mechanical engineering, where the demand for data driven approaches to engineering challenges has recently increased drastically. While promising results have already been achieved by applying machine learning models in this field, the opaqueness of modern machine learning models, such as artificial neural networks, brings its own challenges. A lack of trust in these models often prevents their application and a lack of intuition for their inner workings prevents them from facilitating scientific discoveries about manufacturing processes. This thesis aims to approach these challenges from the unique angle of increasing the amount of immersion used when interacting with models and data throughout the whole machine learning pipeline. Immersion in virtual environments has the ability to facilitate a phenomenon called presence, which can make users perceive the presented stimuli as more real and engage with them much more directly. However, research regarding the effect of immersion on abstract data visualization is lacking. It is argued that a similar phenomenon, in this thesis called data presence, can be achieved with proper immersive visualization tools. Hence, multiple demonstrators were developed that showcase the possibility to facilitate better understanding of data, models, and the underlying processes using increased degrees of immersion. First, general considerations are presented on developing immersive applications for use in everyday work. Then, multiple immersive applications are presented for data labeling, data understanding and model visualization. Each of these applications is evaluated, showing indications that they can indeed lead to benefits for their users. Es laden ein: die Dozentinnen und Dozenten der Informatik

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Survey Lecture - Highlights of UnRAVeL
by Kassing, Jan-Christoph 23 Apr '25

23 Apr '25

Dear all, We invite you to the next UnRAVeL survey lecture talk on Thursdays 12:30 to 14:00, Computer Science Center, Building E2, ground floor, B-IT room 5053.2, given by Jürgen Giesl about "Termination and Complexity Analysis: From Classical to Probabilistic Programs“! -------------------- Titel: Termination and Complexity Analysis: From Classical to Probabilistic Programs Abstract: We give an overview on our results obtained within UnRAVeL. Before the start of the research training group, we had already developed several techniques for automated termination and complexity analysis for different kinds of "classical" programs. We show how these approaches were extended to probabilistic programs due to our research within UnRAVeL. -------------------- Part of the programme of the research training group UnRAVeL is a series of lectures on the topics of UnRAVeL’s research thrusts algorithms and complexity, verification, logic and languages, and their application scenarios. Each lecture is given by one of the researchers involved in UnRAVeL. This years topic is "Highlights of UnRAVeL!". As UnRAVeL nears its conclusion, we take this opportunity to reflect on seven years of excellent research. Through nine talks, we invite you to experience the scientific highlights of our RTG, along with its numerous successes, developments, and collaborations. All interested doctoral researchers and master students are invited to attend the UnRAVeL lecture series 2025 and engage in discussions with researchers and doctoral students. The overall remaining schedule is as following: 24.04.2025 - Jürgen Giesl - Termination and Complexity Analysis: From Classical to Probabilistic Programs 08.05.2025 - Nils Nießen - Uncertainty in Railways 15.05.2025 - Joost-Pieter Katoen - Verification Conquers Fault Tree Analysis: From Theory to Start-Up 22.05.2025 - Britta Peis - On Train Routing and Length-bounded Disjoint Paths 26.06.2025 - Michael Schaub - Oversmoothing in Graph Neural Networks 03.07.2025 - Sebastian Trimpe - Uncertainty in Learning and Control 10.07.2025 - Christopher Morris - Exploring the Power of Graph Neural Networks in Solving Optimization Problems 17.07.2025 - Christina Büsing - Dealing with Uncertainty Inspired by Health Care – a Robust Optimization Approach Kind regards, Jan-Christoph for the organisation committee

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Survey Lecture - Highlights of UnRAVeL
by Kassing, Jan-Christoph 16 Apr '25

16 Apr '25

Dear all, part of the programme of the research training group UnRAVeL is a series of lectures on the topics of UnRAVeL’s research thrusts algorithms and complexity, verification, logic and languages, and their application scenarios. Each lecture is given by one of the researchers involved in UnRAVeL. This years topic is "Highlights of UnRAVeL!". As UnRAVeL nears its conclusion, we take this opportunity to reflect on seven years of excellent research. Through nine talks, we invite you to experience the scientific highlights of our RTG, along with its numerous successes, developments, and collaborations. All interested doctoral researchers and master students are invited to attend the UnRAVeL lecture series 2025 and engage in discussions with researchers and doctoral students. All events take place on Thursdays 12:30 to 14:00, Computer Science Center, Building E2, ground floor, B-IT room 5053.2. The first lecture (tomorrow) is given by Erika Ábrahám about "SMT: Something You Must Try“! -------------------- SMT (Satisfiability Modulo Theories) solving is a technology for the fully automated solution of logical formulas. SMT solvers are general-purpose off-the-shelf solvers, which can be integrated in diverse systems. Due to their impressive efficiency, SMT solvers are nowadays frequently used in a wide variety of applications, including the analysis of probabilistic systems. A typical application encodes real-world problems as logical formulas, whose solutions can be decoded to solutions of the real-world problem. In this talk we give some insights into the mechanisms of SMT solving, discuss some applications in the context of probabilistic systems, and review our own research activities in this area. -------------------- The overall schedule is as following: 17.04.2025 - Erika Ábrahám - SMT: Something You Must Try 24.04.2025 - Jürgen Giesl - Termination and Complexity Analysis: From Classical to Probabilistic Programs 08.05.2025 - Nils Nießen - Uncertainty in Railways 15.05.2025 - Joost-Pieter Katoen - Verification Conquers Fault Tree Analysis: From Theory to Start-Up 22.05.2025 - Britta Peis - On Train Routing and Length-bounded Disjoint Paths 26.06.2025 - Michael Schaub - Oversmoothing in Graph Neural Networks 03.07.2025 - Sebastian Trimpe - Uncertainty in Learning and Control 10.07.2025 - Christopher Morris - Exploring the Power of Graph Neural Networks in Solving Optimization Problems 17.07.2025 - Christina Büsing - Dealing with Uncertainty Inspired by Health Care – a Robust Optimization Approach Kind regards, Jan-Christoph for the organisation committee

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Einladung: Informatik-Oberseminar Lovro Mrkonjić
by Lovro Mrkonjić 03 Apr '25

03 Apr '25

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Montag, 14. April 2025, 15:00 Uhr Ort: Raum 9222 (Informatikzentrum E3, Ahornstraße 55) Referent: Lovro Mrkonjić, M.Sc. LuFG Mathematische Grundlagen der Informatik Thema: Semiring Semantics: Algebraic Foundations, Model Theory, and Strategy Analysis Abstract: Classically, a logical formula is either true or false in a given structure. In the semiring framework, which was originally developed by Green, Karvounarakis and Tannen for databases in 2007, Boolean truth values are replaced with values from an arbitrary commutative semiring, which may carry additional information. For example, evaluating a formula under semiring semantics in a suitable semiring may not only tell us if the formula is true, but also which of the facts in the input structure contribute to the truth of the formula. Classical models are replaced with semiring interpretations, which assign a semiring element to each literal of a model. This prompts the introduction of model theory to the semiring setting. In this talk, we address the following questions from semiring model theory: How does elementary equivalence behave in the semiring setting? Does the compactness theorem still hold under semiring semantics? It turns out that the answers heavily depend on the algebraic properties of the semiring in question. For example, while it is well-known that first-order logic can axiomatize finite structures up to isomorphism in classical semantics, we find that this is not the case under semiring semantics: Over fully idempotent semirings with at least three elements, there are finite interpretations which are elementarily equivalent, but not isomorphic. We also find that some classical results survive in the semiring setting, for example, the compactness theorem holds on most finite, absorptive semirings. The final part of this talk is dedicated to the semiring framework for games, which was introduced by Grädel and Tannen (2020). We present an extension of the semiring framework to imperfect information games and discuss some computational challenges in this setting. Es laden ein: die Dozentinnen und Dozenten der Informatik

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Einladung Informatik-Oberseminar Imke Nachmann
by Sek 18 Mar '25

18 Mar '25

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Donnerstag, 27.03.2025, 14:00 Uhr Ort: Informatikzentrum der RWTH Aachen University, Gebäude E3, 2. Etage, Raum 9222 Referentin: Imke Nachmann, M.Sc. Lehrstuhl für Software Engineering Thema: Functional Modeling of Cyber-Physical Systems Abstract: Engineering Cyber-Physical Systems faces many challenges including the demand to integrate many different forms of functionalities and features. Traditional engineering processes are structured by the physical components and software modules of the final system and the engineering activities are concerned with evolving these components. In these approaches, the information, which components realize which functions and, in particular, which components interact in which way to implement a function, most often remains implicit. This hinders not only the collaboration of experts from different domains but also an agile approach to engineering which becomes efficient through automation of tasks. The shift towards functional requirements gives rise to a conceptual gap between their abstract descriptions and the very detailed descriptions of the system’s implementation. So far, the involved engineering domains have established an understanding of what a system’s function is, but these understandings have not been consolidated and integrated in a suitable interdisciplinary modeling technique. Therefore, we propose a functional development paradigm that promotes development by finding realizations of cyber-physical functions, which transform energy, matter, and data, rather than implementing physical products or software modules directly. Therein, we model a as a network of interacting timed stream processing functions, which specify the desired logical behavior and the physical behavior. By applying this modeling technique to formalize the design process in mechanical engineering, we show how to integrate the functional understanding of software and mechanical systems, which paves the way for agile and holistic model-driven engineering of CPSs. Further, we propose requirements and a meta-model for implementing modeling languages to model these functions Es laden ein: die Dozentinnen und Dozenten der Informatik

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Einladung / Informatik-Oberseminar / Rohit Gupta (Dissertationsvortrag)
by rg.gupta＠siemens.com 14 Mar '25

14 Mar '25

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Donnerstag, 10. April 2025, 14 Uhr Ort: Room 9222, Building E3, Ahornstr. 55 Referent: Rohit Gupta M.Sc. Chair of Software Engineering (Computer Science 3) Thema: A Systematic Approach to Fostering Engineering of Industrial Domain-Specific Modelling Languages Abstract: Domain-Specific Modelling Languages (DSMLs) help modellers and domain experts in various domains such as healthcare, energy, information technology, and so on, in reducing the gap between the problem space and the solution space by placing models at the centre of development activities. This shift towards model-driven development (MDD), where models are introduced at early stages in any software or systems engineering process and are the primary software engineering artefacts, allows modellers to design complex, heterogeneous real-world abstractions of their systems. In such complex systems, concepts from individual domains are often integrated as part of the bigger language infrastructure. Specifically in an industrial setting, the methodologies to describe a systematic engineering process for developing such complex yet modular and reusable DSMLs that provides a seamless modelling experience to modellers in both the large scale organisations as well as in small and medium enterprises is still largely neglected. Accordingly, this thesis is aimed at providing the means to engineer graphical DSMLs that are specifically focussed on industrial contexts. Based on existing approaches, this work presents a systematic approach to fostering the engineering of industrial DSMLs by composing reusable language infrastructure parts without the need for creating completely new language infrastructure for similar domains every time. These reusable units of a DSML, termed DSML building blocks, consist of reusable language components that, entirely or in part, contributes to the technical definition of the language itself. The language components compose through different forms of language composition to form heterogeneous, integrated DSMLs. To foster the interoperability of such common language infrastructure parts between modelling environments, a bidirectional exchange mechanism is detailed in this work. This work further provides guidelines and design decisions that language engineers should consider for their language infrastructure in order to elevate the overall experience of modellers. An approach for integrating methods, techniques, and concepts in terms of guidance and recommendations for modellers is detailed in this thesis that aims to move away from plain technical views of models to instead model-aware and dynamic views that are focussed on the current modelling situation of such modellers. Overall, this thesis presents approaches to modularly build reusable units of DSMLs that compose together. The approaches presented in this thesis allows language engineers to provide a more complete and integrated language infrastructure that is ultimately aimed at improving the modelling experience of practitioners in the industry. Es laden ein: die Dozentinnen und Dozenten der Informatik

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Einladung: Informatik-Oberseminar Christian Martin Fiedler
by DSME-Office 12 Mar '25

12 Mar '25

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Dienstag, 25. März 2025, 14.00 Uhr Ort: Seminarraum 423, 4. OG, Theaterstraße 35-39, 52062 Aachen Referent: Christian Martin Fiedler M.Sc. Institut für Data Science im Maschinenbau (DSME) Thema: Contributions to Kernel Methods in Systems and Control Abstract: Machine learning is increasingly used in systems and control, which is motivated by challenging control, simulation and analysis problems, abundant data and computing resources, as well as impressive theoretical and methodological advances in machine learning. The established class of kernel methods is of particular interest in this context, due to their rich theory, modularity, efficient and reliable algorithms, and indeed kernel methods are frequently used in systems and control. We present two exemplary and complementary contributions to this flourishing field. First, many learning-based control approaches are based on combining uncertainty bounds for Gaussian process (GP) regression with robust control methods. We revisit the foundations of this domain by consolidating, improving, and carefully evaluating the required uncertainty bounds, and use them in learning-enhanced control applications. Furthermore, we discuss a severe practical limitation of these approaches, the a priori knowledge of an upper bound on the reproducing kernel Hilbert space (RKHS) norm of the target function, and propose to combine geometric assumptions together with kernel methods as a promising alternative. Second, we initiate a new research direction by combining kernels with mean field limits as appearing in kinetic theory. Motivated by learning problems on large-scale multiagent systems, we introduce mean field limits of kernels, and provide an extensive theory for the resulting RKHSs. This is used in turn in the analysis of kernel-based statistical learning in the mean field limit, which not only is a novel form of large-scale limit in theoretical machine learning, but provides also a solid foundation for applications in kinetic theory. Es laden ein: die Dozentinnen und Dozenten der Informatik

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Einladung Informatik Oberseminar Lubna Ali
by Bombelka, Angelika 28 Feb '25

28 Feb '25

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Dienstag, 30. Januar 2024, 14.00 Uhr Ort: 9222, E3, Ahornstr. 55 und hybrid via Zoom (https://rwth.zoom-x.de/j/64937773189?pwd=eGttNUMzSElnQUVkc3FrYzBqK2F4UT09) Referent: Lubna Ali M.Sc. RWTH Lehr- und Forschungsgebiet Informatik 9 (Lerntechnologien) Thema: convOERter: A Technical Assistance Tool to Support Semi-Automatic Conversion of Images in Educational Materials as OER Abstract: Open Educational Resources (OER) are seen as an important element in the process of digitizing higher education teaching and as essential building blocks for openness in education. They can be defined as teaching, learning, and research materials that have been made openly available, shareable, and modifiable. OER include different types of resources such as full courses, textbooks, videos, presentations, tests, and images, which are usually published under the open Creative Commons licences. OER can play an important role in improving education by facilitating access to high quality digital educational materials. Accordingly, there is a steady increase among higher education institutions to participate in the so-called "open movement" in general and in utilizing OER in particular. Nevertheless, there are many challenges that still face the deployment of OER in the educational context. One of the main challenges is the production of new OER materials and converting already existing materials into OER, which could be viable by qualifying educators through training courses and/or supporting them with specific tools. There are many platforms and tools that support the creation of new OER content. However, to our knowledge, there are no tools that perform fully- or semi-automatic conversion of already existing educational materials. This identified gap was the basis for the design and implementation of the OER conversion tool (convOERter). The tool supports the user by semi-automatically converting educational materials containing images into OER-compliant materials. The main functionality of the tool is based on reading a file, extracting all images as well as all possible metadata, and substituting the extracted images with OER elements in a semi-automated way. The retrieved OER images are referenced and licenced properly according to the known TASLL rule. Finally, the entire file is automatically licenced under Creative Commons excluding specific elements from the entire licence such as logos. In order to evaluate the effectiveness of the tool in promoting the use of OER, a comprehensive user study was conducted with educators and OER enthusiastic at different universities. The study was accomplished by offering a series of OER evaluation workshops to compare the conversion efficiency of the tool with manual conversion. The results show that using the conversion tool improves the conversion process in terms of speed, license quality, and total efficiency. These results highlight that the tool can be a valuable addition to the community, especially for users less experienced with OER. As a future work, it is intended to further develop the tool and improve its functionality. Additionally, a long-term study can be conducted to assess the impact of the tool in facilitating and enhancing the production of OER on a larger scale. Es laden ein: die Dozentinnen und Dozenten der Informatik

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Einladung: Informatik-Oberseminar Simon Schwitanski
by Simon Schwitanski 21 Jan '25

21 Jan '25

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Mittwoch, 5. Februar 2025, 13.00 Uhr Ort: Seminarraum 003, IT Center, Kopernikusstraße 6 Referent: Simon Schwitanski, M.Sc. Lehrstuhl für Hochleistungsrechnen (Informatik 12) Thema: Modeling Synchronization and Consistency for Data Race Detection in Remote Memory Access Programs Abstract: The increasing parallelism in today's supercomputers requires scalable parallel programming methods with efficient communication models. The traditional communication model in scientific computing is message passing: Both the sending and receiving process participate actively in the data exchange via messages. Remote Memory Access (RMA) models provide an alternative communication method where processes can access the memory of other processes directly. RMA models avoid unnecessary synchronization between processes and outperform the traditional message-passing model in modern supercomputers. However, they require users to explicitly ensure the synchronization and consistency of memory accesses through corresponding API calls. Otherwise, concurrent conflicting memory accesses lead to data races with undefined behavior. The non-deterministic nature of data races, commonly known from shared-memory programming, makes them difficult to detect manually. This thesis investigates data races in RMA programs and provides novel scalable methods to detect them at runtime. A classification of data races in the RMA models MPI~RMA, OpenSHMEM, and GASPI shows that synchronization and consistency are the two key properties that a correctness tool must capture to identify RMA races. This thesis provides formal models that allow analyzing both properties in RMA programs. The synchronization model analyzes the happened-before relation of events using a vector clock exchange. It captures the synchronization state of processes at runtime. The consistency model formalizes a relation defining when a remote memory access is guaranteed to be completed. Both models are combined in a generalized on-the-fly race detection model that can detect RMA data races independent of the concrete RMA model used in an application. The developed race detection model is implemented in a tool named RMASanitizer. It combines the shared-memory race detector ThreadSanitizer with the correctness checking tool MUST to detect RMA data races in MPI RMA, OpenSHMEM, and GASPI at runtime. For the evaluation, this thesis provides RMARaceBench, a classification quality benchmark suite designed to quantify the detection accuracy of RMA race detection tools. The evaluation with RMARaceBench shows that RMASanitizer has the highest detection accuracy compared to other state-of-the-art RMA race detectors. An overhead study with RMA proxy applications running with up to 700 processes shows that RMASanitizer is applicable to large-scale workloads. Es laden ein: die Dozentinnen und Dozenten der Informatik

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