TY - CONF AB - The first order optimality conditions of optimal control problems (OCPs) can be regarded as boundary value problems for Hamiltonian systems. Variational or symplectic discretisation methods are classically known for their excellent long term behaviour. As boundary value problems are posed on intervals of fixed, moderate length, it is not immediately clear whether methods can profit from structure preservation in this context. When parameters are present, solutions can undergo bifurcations, for instance, two solutions can merge and annihilate one another as parameters are varied. We will show that generic bifurcations of an OCP are preserved under discretisation when the OCP is either directly discretised to a discrete OCP (direct method) or translated into a Hamiltonian boundary value problem using first order necessary conditions of optimality which is then solved using a symplectic integrator (indirect method). Moreover, certain bifurcations break when a non-symplectic scheme is used. The general phenomenon is illustrated on the example of a cut locus of an ellipsoid. AU - Offen, Christian AU - Ober-Blöbaum, Sina ID - 22894 KW - optimal control KW - catastrophe theory KW - bifurcations KW - variational methods KW - symplectic integrators SN - 2405-8963 TI - Bifurcation preserving discretisations of optimal control problems VL - 54(19) ER - TY - JOUR AB - In the last two decades, variably doped strontium barium niobate (SBN) has attracted a lot of scientific interest mainly due to its specific non-linear optical response. Comparably, the parental compound, i.e., undoped SBN, appears to be less studied so far. Here, two different cuts of single-crystalline nominally pure strontium barium niobate in the composition Sr0.61Ba0.39Nb2O6 (SBN61) are comprehensively studied and analyzed with regard to their photoconductive responses. We present conductance measurements under systematically varied illumination conditions along either the polar z-axis or perpendicular to it (x-cut). Apart from a pronounced photoconductance (PC) already under daylight and a large effect upon super-bandgap illumination in general, we observe (i) distinct spectral features when sweeping the excitation wavelength over the sub-bandgap region as then discussed in the context of deep and shallow trap states, (ii) extremely slow long-term relaxation for both light-on and light-off transients in the range of hours and days, (iii) a critical dependence of the photoresponse on the pre-illumination history of the sample, and (iv) a current–voltage hysteresis depending on both the illumination and the electrical-measurement conditions in a complex manner. AU - Beyreuther, Elke AU - Ratzenberger, Julius AU - Roeper, Matthias AU - Kirbus, Benjamin AU - Rüsing, Michael AU - Ivleva, Liudmila I. AU - Eng, Lukas M. ID - 47964 IS - 7 JF - Crystals KW - Inorganic Chemistry KW - Condensed Matter Physics KW - General Materials Science KW - General Chemical Engineering SN - 2073-4352 TI - Photoconduction of Polar and Nonpolar Cuts of Undoped Sr0.61Ba0.39Nb2O6 Single Crystals VL - 11 ER - TY - JOUR AB - Family-Literacy-Programme stellen eine gute Möglichkeit dar, Eltern in Bildungsprozesse einzubeziehen. Am Beispiel des Programms „LIFE – Lesen in Familie erleben“ wird die Wirkung auf elterliche Unterstützung beim Lesenlernen von Erstklässler*innen unter Einbezug von Eltern- und Kinderperspektive untersucht. Sowohl direkt nach dem Programm als auch ein halbes Jahr später wirkte das Programm positiv auf verschiedene Arten der Anschlusskommunikation beim gemeinsamen Lesen. AU - Bonanati, Sabrina AU - Gruchel, Nicole AU - Kurock, Ricarda AU - Buhl, Heike M. ID - 32562 IS - 3 JF - Die Deutsche Schule KW - Kooperation KW - Familie KW - Lesekompetenz KW - Längsschnittstudie KW - Intervention SN - 0012-0731 TI - Teilhabe von Eltern an schulischem Lernen mit Family-Literacy-Programmen. Langzeiteffekte von „LIFE – Lesen in Familie erleben“ auf die elterliche Unterstützung beim Lesenlernen VL - 113 ER - TY - CONF AB - Automatic transcription of meetings requires handling of overlapped speech, which calls for continuous speech separation (CSS) systems. The uPIT criterion was proposed for utterance-level separation with neural networks and introduces the constraint that the total number of speakers must not exceed the number of output channels. When processing meeting-like data in a segment-wise manner, i.e., by separating overlapping segments independently and stitching adjacent segments to continuous output streams, this constraint has to be fulfilled for any segment. In this contribution, we show that this constraint can be significantly relaxed. We propose a novel graph-based PIT criterion, which casts the assignment of utterances to output channels in a graph coloring problem. It only requires that the number of concurrently active speakers must not exceed the number of output channels. As a consequence, the system can process an arbitrary number of speakers and arbitrarily long segments and thus can handle more diverse scenarios. Further, the stitching algorithm for obtaining a consistent output order in neighboring segments is of less importance and can even be eliminated completely, not the least reducing the computational effort. Experiments on meeting-style WSJ data show improvements in recognition performance over using the uPIT criterion. AU - von Neumann, Thilo AU - Kinoshita, Keisuke AU - Boeddeker, Christoph AU - Delcroix, Marc AU - Haeb-Umbach, Reinhold ID - 26770 KW - Continuous speech separation KW - automatic speech recognition KW - overlapped speech KW - permutation invariant training T2 - Interspeech 2021 TI - Graph-PIT: Generalized Permutation Invariant Training for Continuous Separation of Arbitrary Numbers of Speakers ER - TY - CONF AU - von Neumann, Thilo AU - Boeddeker, Christoph AU - Kinoshita, Keisuke AU - Delcroix, Marc AU - Haeb-Umbach, Reinhold ID - 29173 T2 - Speech Communication; 14th ITG Conference TI - Speeding Up Permutation Invariant Training for Source Separation ER - TY - CONF AB - In this paper we present our system for the Detection and Classification of Acoustic Scenes and Events (DCASE) 2021 Challenge Task 4: Sound Event Detection and Separation in Domestic Environments, where it scored the fourth rank. Our presented solution is an advancement of our system used in the previous edition of the task.We use a forward-backward convolutional recurrent neural network (FBCRNN) for tagging and pseudo labeling followed by tag-conditioned sound event detection (SED) models which are trained using strong pseudo labels provided by the FBCRNN. Our advancement over our earlier model is threefold. First, we introduce a strong label loss in the objective of the FBCRNN to take advantage of the strongly labeled synthetic data during training. Second, we perform multiple iterations of self-training for both the FBCRNN and tag-conditioned SED models. Third, while we used only tag-conditioned CNNs as our SED model in the previous edition we here explore sophisticated tag-conditioned SED model architectures, namely, bidirectional CRNNs and bidirectional convolutional transformer neural networks (CTNNs), and combine them. With metric and class specific tuning of median filter lengths for post-processing, our final SED model, consisting of 6 submodels (2 of each architecture), achieves on the public evaluation set poly-phonic sound event detection scores (PSDS) of 0.455 for scenario 1 and 0.684 for scenario as well as a collar-based F1-score of 0.596 outperforming the baselines and our model from the previous edition by far. Source code is publicly available at https://github.com/fgnt/pb_sed. AU - Ebbers, Janek AU - Haeb-Umbach, Reinhold ID - 29308 SN - 978-84-09-36072-7 T2 - Proceedings of the 6th Detection and Classification of Acoustic Scenes and Events 2021 Workshop (DCASE2021) TI - Self-Trained Audio Tagging and Sound Event Detection in Domestic Environments ER - TY - CONF AB - Recently, there has been a rising interest in sound recognition via Acoustic Sensor Networks to support applications such as ambient assisted living or environmental habitat monitoring. With state-of-the-art sound recognition being dominated by deep-learning-based approaches, there is a high demand for labeled training data. Despite the availability of large-scale data sets such as Google's AudioSet, acquiring training data matching a certain application environment is still often a problem. In this paper we are concerned with human activity monitoring in a domestic environment using an ASN consisting of multiple nodes each providing multichannel signals. We propose a self-training based domain adaptation approach, which only requires unlabeled data from the target environment. Here, a sound recognition system trained on AudioSet, the teacher, generates pseudo labels for data from the target environment on which a student network is trained. The student can furthermore glean information about the spatial arrangement of sensors and sound sources to further improve classification performance. It is shown that the student significantly improves recognition performance over the pre-trained teacher without relying on labeled data from the environment the system is deployed in. AU - Ebbers, Janek AU - Keyser, Moritz Curt AU - Haeb-Umbach, Reinhold ID - 29306 T2 - Proceedings of the 29th European Signal Processing Conference (EUSIPCO) TI - Adapting Sound Recognition to A New Environment Via Self-Training ER - TY - CHAP AU - Schneider, Jennifer Nicole ED - Beutner, Marc ED - Pechuel, Rasmus ED - Schneider, Jennifer ID - 47957 T2 - Fostering Digitisation and Industry 4.0: Education – Vocation - Industry – Future. New Opportunities and Challenges for European VET. Insights in the DigI-VET Project TI - Digital transformation in industry ER - TY - CHAP AU - Schneider, Jennifer ED - Beutner, Marc ED - Pechuel, Rasmus ED - Schneider, Jennifer ID - 47966 T2 - Fostering Digitisation and Industry 4.0: Education – Vocation - Industry – Future. New Opportunities and Challenges for European VET. Insights in the DigI-VET Project TI - Teaching and Learning Materials ER - TY - JOUR AB - One objective of current research in explainable intelligent systems is to implement social aspects in order to increase the relevance of explanations. In this paper, we argue that a novel conceptual framework is needed to overcome shortcomings of existing AI systems with little attention to processes of interaction and learning. Drawing from research in interaction and development, we first outline the novel conceptual framework that pushes the design of AI systems toward true interactivity with an emphasis on the role of the partner and social relevance. We propose that AI systems will be able to provide a meaningful and relevant explanation only if the process of explaining is extended to active contribution of both partners that brings about dynamics that is modulated by different levels of analysis. Accordingly, our conceptual framework comprises monitoring and scaffolding as key concepts and claims that the process of explaining is not only modulated by the interaction between explainee and explainer but is embedded into a larger social context in which conventionalized and routinized behaviors are established. We discuss our conceptual framework in relation to the established objectives of transparency and autonomy that are raised for the design of explainable AI systems currently. AU - Rohlfing, Katharina J. AU - Cimiano, Philipp AU - Scharlau, Ingrid AU - Matzner, Tobias AU - Buhl, Heike M. AU - Buschmeier, Hendrik AU - Esposito, Elena AU - Grimminger, Angela AU - Hammer, Barbara AU - Haeb-Umbach, Reinhold AU - Horwath, Ilona AU - Hüllermeier, Eyke AU - Kern, Friederike AU - Kopp, Stefan AU - Thommes, Kirsten AU - Ngonga Ngomo, Axel-Cyrille AU - Schulte, Carsten AU - Wachsmuth, Henning AU - Wagner, Petra AU - Wrede, Britta ID - 24456 IS - 3 JF - IEEE Transactions on Cognitive and Developmental Systems KW - Explainability KW - process ofexplaining andunderstanding KW - explainable artificial systems SN - 2379-8920 TI - Explanation as a Social Practice: Toward a Conceptual Framework for the Social Design of AI Systems VL - 13 ER - TY - GEN AU - Fastlabend-Vargas, Daniel ID - 49589 T2 - H-Soz-Kult TI - Rezension zu: Dräger, Marco: Denkmäler im Geschichtsunterricht Frankfurt am Main 2021. ER - TY - JOUR AB - The implementation of control systems in metal forming processes improves product quality and productivity. By controlling workpiece properties during the process, beneficial effects caused by forming can be exploited and integrated in the product design. The overall goal of this investigation is to produce tailored tubular parts with a defined locally graded microstructure by means of reverse flow forming. For this purpose, the proposed system aims to control both the desired geometry of the workpiece and additionally the formation of strain-induced α′-martensite content in the metastable austenitic stainless steel AISI 304 L. The paper introduces an overall control scheme, a geometry model for describing the process and changes in the dimensions of the workpiece, as well as a material model for the process-induced formation of martensite, providing equations based on empirical data. Moreover, measurement systems providing a closed feedback loop are presented, including a novel softsensor for in-situ measurements of the martensite content. AU - Riepold, Markus AU - Arian, Bahman AU - Vasquez, Julian Rozo AU - Homberg, Werner AU - Walther, Frank AU - Trächtler, Ansgar ID - 23469 JF - Advances in Industrial and Manufacturing Engineering SN - 2666-9129 TI - Model approaches for closed-loop property control for flow forming ER - TY - GEN AU - Huybrechts, Yves AU - Scholliers, Peter ID - 49759 TI - "Searching for a Belgian culinary identity - Referat von Prof. Dr. Peter Scholliers" (VIDEO) ER - TY - GEN AU - Huybrechts, Yves ID - 49765 TI - "Der belgische Symbolismus - Interview mit dem Direktor der Alten Nationalgalerie, Dr. Ralph Gleis" (PODCAST) ER - TY - GEN AU - Huybrechts, Yves ID - 49752 TI - "Gebaute Träume - Wohnkultur in Flandern und Wallonien" (VIDEO) ER - TY - CHAP AU - Neiske, Iris ED - Buchner, J. ED - Freisleben-Teutscher, C. F. ED - Neiske, I. ED - Morisse, I. ID - 49867 SN - 9783755749165 T2 - Inverted Classroom and beyond 2021 10 Jahre #icmbeyond. Norderstedt TI - Geflippte E-Tutor*innenschulungen ER - TY - JOUR AB - The aim of the present study is to bring new momentum into research on students’ understanding of academic writing. Drawing on the idea that metaphors give insight into implicit conceptions of abstract entities and processes, we developed a detailed and differentiated set of conceptual metaphors that can be used to study student ideas about writing in research, teaching, and interventions. A large sample of undergraduates produced their everyday understanding of writing in short texts beginning with a self-generated metaphor. Based on theories from cognitive linguistics, the conceptual metaphors in their texts were analyzed in terms of their action quality (transitivity) and spatiality (spatial primitives). The undergraduates’ conceptualizations were very heterogeneous. Most metaphors depart strongly from scientific approaches to academic writing within cognitive psychology and sociocultural theory. Roughly half of the metaphors could be collated to one of four metaphor systems. Depending on the desired degree of abstraction or concreteness, conceptual metaphors or metaphor systems can be employed in further studies to illuminate thinking about writing. AU - Scharlau, Ingrid AU - Karsten, Andrea AU - Rohlfing, Katharina ID - 28696 IS - 3 JF - Journal of Writing Research KW - metaphor analysis KW - academic writing KW - transitivity KW - spatial primitives SN - 2030-1006 TI - Building, emptying out, or dreaming? Action structures and space in undergraduates’ metaphors of academic writing VL - 12 ER - TY - JOUR AU - Krollmann, Rabea AU - Schmidt, Rebecca AU - Spill, Annika ID - 45252 JF - blog interdisziplinäre geschlechterforschung TI - Grenzüberschreitung und Distanzierung – Geschlechterforschung in universitären Toiletten ER - TY - CONF AU - Hohmann, Sascha AU - Gschwind, Stéphane AU - Müller, Andreas AU - Nordine, Jeffrey AU - Riesen, Timm-Emanuel ED - Grötzebauch, Helmuth ID - 50188 IS - 2021 SN - 2191-379X T2 - PhyDid B TI - Das Stellarium Gornergrat ER - TY - JOUR AU - Ekström, Sylvia AU - Frey, Jonas AU - Gschwind, Stéphane AU - Hohmann, Sascha AU - Müller, Andreas AU - Riesen, Timm-Emanuel AU - Ruffieux, Simon AU - Schlatter, Peter ID - 50187 IS - 63 JF - SPG-Mitteilungen TI - Stellarium Gornergrat – A swiss robotic Observatory for Education and Citizen Science ER -