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

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 15 Mar '25

15 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 13 Mar '25

13 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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Einladung: Informatik-Oberseminar Herr Sascha Martin Welten
by Maaßen, Leany 07 Jan '25

07 Jan '25

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Freitag, 17.01.2025, 14:00-15:00 Uhr Ort: Raum 5053.2 (großer B-IT-Hörsaal)/Informatikzentrum, Ahornstraße 55 Referent: Herr Sascha Martin Welten, M. Sc. Lehrstuhl Informatik 5 Thema: Methods for Practical Data Sharing and Decentralised Analytics: An Integrated Approach Abstract: This dissertation addresses the challenges of sharing data across organisational boundaries, which is crucial for scientific progress, particularly with the rise of AI and data-driven approaches. While data sharing is essential for innovation, concerns around privacy, security, and regulatory compliance often limit access to valuable data. This work introduces an integrated framework that combines privacy-preserving methods with Decentralised Analytics (DA), addressing key requirements such as trust, controlled access, and data heterogeneity. The research develops a DevOps-inspired lifecycle, 'DAOps', for managing shared data analysis, implemented in a novel platform, PADME (Platform for Analytics and Distributed Machine Learning for Enterprises). PADME supports various types of analysis and enables decentralised model training, offering a privacy-preserving alternative to traditional centralised methods. The platforms evaluation in healthcare and hydrology confirms its operational readiness and applicability to real-world research scenarios. Key findings highlight the importance of common data schema standards and balanced data distributions for successful data sharing. Ultimately, this dissertation contributes to the practical realisation of data-sharing concepts, promoting secure, decentralised data analysis and fostering data-driven research collaborations. 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. Gerhard Lakemeyer Ph.D., JunProf. Dr. Sandra Geisler 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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Einladung: Informatik-Oberseminar Alexander Kugler
by Kugler, Alexander 19 Dec '24

19 Dec '24

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Dienstag, 7. Januar 2025, 16.00 Uhr Ort: Lehrstuhl i11, Im Süsterfeld 9, Aachen, Raum R259 im 2. OG Referent: Alexander Kugler M.Sc. Chair of Computer Science 11 - Embedded Software Thema: Test Case Generation from Natural Language Requirements for Embedded Systems with Semantic Role Labeling Abstract: In this talk, the application of Semantic Role Labeling (SRL) for the generation of test cases from natural language requirements for embedded systems is explored. The approach, labelled Test Generation with Semantic Role Labeling (TG-SRL), is composed of five stages and combines machine learning with a rule-based approach. Information extracted via SRL is initially aggregated into logical expressions before being translated into First-Order Logic (FOL) formulae. Test case generation is achieved using Satisfiability Modulo Theory (SMT) solving. By modifying the SMT instance according to defined tactics, a test suite is generated. The thesis concludes with an evaluation of TG-SRL using a mutant-based strength analysis, and a comparison with the Nat2Test approach from Carvalho et al. TG-SRL performs favorably and provides valuable insights into employing Natural Language Processing (NLP) methods, and in particular SRL, in the field of test case generation. The methods and concepts presented in this thesis have been implemented in a publicly available research framework. Es laden ein: die Dozentinnen und Dozenten der Informatik

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[sekretariate] Einladung: Informatik-Oberseminar Kevin Batz
by Elke Ohlenforst 11 Dec '24

11 Dec '24

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Freitag, 20.12.2024, 13:00 Uhr Ort: Raum 9222 (E3, Informatikzentrum, Ahornstr. 55) Referent: Kevin Batz, M.Sc. Lehrstuhl für Softwaremodellierung und Verifikation (Informatik 2) Thema: Automated Deductive Verification of Probabilistic Programs Abstract: We study both foundational and practical aspects of the automated deductive verification of discrete probabilistic programs. Our special emphasis is on the verification of possibly unbounded loops by quantitative loop invariants. We build upon Kozen's, McIver & Morgan's, and Kaminski's weakest preexpectation calculus for reasoning about expected outcomes such as the probability of terminating in some postcondition or the expected final value of a program variable. The weakest preexpectation calculus replaces predicates from classical program verification by more general expectations - functions mapping program states to numbers instead of truth values. We study a syntax for specifying expectations, providing a foundation for automated deductive probabilistic program verifiers. We prove that our syntax is expressive and hence obtain a relatively complete verification system for reasoning about expected outcomes. We then present three different approaches for automating the verification of bounds on expected outcomes of linear loops, all of which combine weakest preexpectation reasoning with Satisfiability Modulo Theories (SMT) techniques: 1. We revisit two well-established verification techniques for transition systems, k-induction and bounded model checking (BMC), in the more general setting of bounding least fixpoints of functions over complete lattices, yielding latticed k-induction and latticed BMC. Instantiating our latticed techniques with the weakest preexpectation calculus enables the fully automatic verification of linear loops taken from the literature. 2. We present a counterexample-guided inductive synthesis approach for the synthesis of quantitative loop invariants. This enables the fully automatic verification of bounds on both expected outcomes and expected runtimes. Our implementation synthesizes quantitative invariants of various linear loops taken from the literature, can beat state-of-the-art probabilistic model checkers on finite-state programs, and is competitive with modern tools dedicated to invariant synthesis or expected runtime reasoning. 3. We present PrIC3 - the first truly quantitative extension of the state-of-the-art qualitative symbolic model checking algorithm IC3 to symbolic model checking of Markov decision processes. By marrying PrIC3 with the weakest preexpectation calculus, we obtain a symbolic model checking algorithm for probabilistic programs. Alongside, we present an implementation of PrIC3 featuring IC3-specific techniques such as generalization. ------------------------------------------------------------------------ Es laden ein: die Dozentinnen und Dozenten der Informatik _______________________________________________ informatik-sekretariate Mailingliste -- informatik-sekretariate(a)lists.rwth-aachen.de Um den Newsletter abzubestellen, senden Sie bitte eine E-Mail an informatik-sekretariate-leave(a)lists.rwth-aachen.de

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Einladung: Informatik-Oberseminar Patrick Schmidt
by Schmidt, Patrick 11 Dec '24

11 Dec '24

+********************************************************************** * * * Einladung * * * * Informatik-Oberseminar * * * +********************************************************************** Zeit: Mittwoch, 18. Dezember 2024, 13:15 Uhr Ort: Raum 118, Erweiterungsbau 3, Ahornstr. 55 Referent: Patrick Schmidt M.Sc. Lehrstuhl für Informatik 8 Thema: Intrinsic Optimization of Maps Between Surfaces Abstract: This talk presents a series of works focusing on the construction and optimization of high-quality maps between surfaces in 3D. These surface maps establish point-to-point correspondences between multiple 3D models, enabling applications such as attribute transfer, shape interpolation, shape co-analysis, compatible remeshing, and more. We introduce a novel framework to generate surface homeomorphisms—maps that guarantee continuity and bijectivity—while minimizing intrinsic mapping distortion. Along the way, we will explore constructions in spherical and hyperbolic geometry and discuss practical solutions for continuous optimization of geometric problems using automatic differentiation. Es laden ein: die Dozentinnen und Dozenten der Informatik

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