@inbook{65518, abstract = {{Abstract Optically assisted digital-to-analog converters (DACs) using Nyquist pulse sequences (NPSs) are presented and investigated. Therefore, NPSs are mathematically described and analyzed. Based on this, the operating principle of a precise optical Nyquist pulse synthesizer digital-to-analog converter (PONyDAC) is described. Possible architectures of PONyDAC are derived and compared in terms of performance and practicability. Moreover, the limits of PONyDAC systems and their superiority over classical electronic DACs are discussed. Furthermore, discrete building-block based implementations and monolithic implementations in electronic-photonic integrated circuits (EPICs) are presented. To enable a practicable monolithic integration, a shrinkage of the Mach-Zehnder modulators (MZMs) has been performed by applying forward-biased phase shifters (FB-PSs). These FB-PSs are analyzed and modeled to allow the precise and reliable design of PONyDAC systems with multiple MZMs. Finally, data conversion and data transmission experiments are carried out to demonstrate the systems functionality, quantify its performance, and prove their superiority over purely electronic DACs.}}, author = {{Scheytt, J. Christoph and Schwabe, Tobias and Singh, Karanveer and Kress, Christian and Schneider, Thomas}}, booktitle = {{Electronic-Photonic Integrated Systems for Ultrafast Signal Processing}}, editor = {{Scheytt, J. Christoph and Kress, Christian and Berroth, Manfred and Pachnicke, Stephan and Witzens, Jeremy}}, isbn = {{9783032083395}}, publisher = {{Springer Nature Switzerland}}, title = {{{Precise Optical Nyquist Pulse Synthesizer Digital-to-Analog Converter}}}, doi = {{10.1007/978-3-032-08340-1_4}}, year = {{2026}}, } @book{65256, editor = {{Scheytt, J. Christoph and Kress, Christian and Berroth, Manfred and Pachnicke, Stephan and Witzens, Jeremy}}, isbn = {{9783032083395}}, publisher = {{Springer Nature Switzerland}}, title = {{{Electronic-Photonic Integrated Systems for Ultrafast Signal Processing}}}, doi = {{10.1007/978-3-032-08340-1}}, year = {{2026}}, } @article{65554, abstract = {{Abstract An algorithm for cutting solid objects in a topology‐controlled manner is presented. Concretely, given a loop on the object boundary, a disk‐topology cut surface bounded by the loop is constructed in the interior. In contrast to various previous approaches, both disk topology and conformance to the prescribed loop are ensured by construction, while supporting not only contractible but also incontractible loops on the boundaries of manifold objects of higher genus and arbitrary non‐trivial topology. We describe an implementation of this algorithm in the discrete setting, with triangle mesh cut surfaces embedded in tetrahedral mesh objects. Making use of this novel cutting algorithm, we describe a method for the reliable construction of bijective volumetric maps between solid objects, demonstrating the algorithm's utility. This mapping method overcomes restrictions of the state of the art to topological balls, extending coverage to objects of arbitrary genus, specifically so‐called 1 ‐handlebodies. }}, author = {{Hinderink, Steffen and Campen, Marcel}}, issn = {{0167-7055}}, journal = {{Computer Graphics Forum}}, publisher = {{Wiley}}, title = {{{DiskScissors: Cutting Arbitrary‐Topology Solids for Bijective Mapping}}}, doi = {{10.1111/cgf.70379}}, year = {{2026}}, } @inproceedings{65567, abstract = {{We introduce the notion of contrastive ABox explanations to answer questions of the type “Why is a an instance of C, but b is not?”. While there are various approaches for explaining positive entailments (why is C(a) entailed by the knowledge base) as well as missing entailments (why is C(b) not entailed) in isolation, contrastive explanations consider both at the same time, which allows them to focus on the relevant commonalities and differences between a and b. We develop an appropriate notion of contrastive explanations for the special case of ABox reasoning with description logic ontologies, and analyze the computational complexity for different variants under different optimality criteria, considering lightweight as well as more expressive description logics. We implemented a first method for computing one variant of contrastive explanations, and evaluated it on generated problems for realistic knowledge bases.}}, author = {{Koopmann, Patrick and Mahmood, Yasir and Ngonga Ngomo, Axel-Cyrille and Tiwari, Balram}}, booktitle = {{Proceedings of the AAAI Conference on Artificial Intelligence}}, issn = {{2374-3468}}, number = {{23}}, pages = {{19189--19197}}, publisher = {{Association for the Advancement of Artificial Intelligence (AAAI)}}, title = {{{Can You Tell the Difference? Contrastive Explanations for ABox Entailments}}}, doi = {{10.1609/aaai.v40i23.38993}}, volume = {{40}}, year = {{2026}}, } @article{61759, abstract = {{Intersection distribution and non-hitting index are concepts introduced recently by Li and Pott as a new way to view the behaviour of a collection of finite field polynomials. With both an algebraic interpretation via the intersection of a polynomial with a set of lines, and a geometric interpretation via a (q+1)-set possessing an internal nucleus, the concepts have proved their usefulness as a new way to view various long-standing problems, and have applications in areas such as Kakeya sets. In this paper, by exploiting connections with diverse areas including the theory of algebraic curves, cyclotomy and the enumeration of irreducible polynomials, we establish new results and resolve various Open Problems of Li and Pott. We prove geometric results which shed new light on the relationship between intersection distribution and projective equivalence of polynomials, and algebraic results which describe and characterise the degree of Sf - the index of the largest non-zero entry in the intersection distribution of f. We provide new insights into the non-hitting spectrum, and show the limitations of the non-hitting index as a tool for characterisation. Finally, the benefits provided by the connections to other areas are evidenced in two short new proofs of the cubic case. }}, author = {{Klawuhn, Lukas-André Dominik and Huczynska, Sophie and Paterson, Maura}}, journal = {{Finite Fields and Their Applications}}, publisher = {{Elsevier}}, title = {{{The Intersection Distribution: New Results and Perspectives}}}, doi = {{10.1016/j.ffa.2026.102828}}, volume = {{114}}, year = {{2026}}, } @inproceedings{65586, author = {{Zeipert, Henning and Claes, Leander and Hölscher, Jonas and Wippermann, Mareen and Henning, Bernd}}, booktitle = {{Fortschritte der Akustik - DAGA 2026}}, pages = {{1566–1569}}, title = {{{An Approach for the Efficient Solution of Eigenvalue-based Inverse Problems for the Material Characterisation Using Guided Acoustic Waves}}}, doi = {{10.71568/DAGA2026.043}}, year = {{2026}}, } @inproceedings{65587, author = {{Claes, Leander}}, booktitle = {{Fortschritte der Akustik - DAGA 2026}}, pages = {{1089–1092}}, title = {{{Simultaneous measurement of bulk and shear viscosity using guided acoustic waves}}}, doi = {{10.71568/DAGA2026.006}}, year = {{2026}}, } @inbook{65521, abstract = {{We present recent progress made towards ultra-broadband photonically assisted analog-to-digital converters, that leverage both the low jitter of best-of-class mode-locked lasers as well as the capability of optics to break down broadband signals into multiple lower speed tributaries that can be better handled by electronics. We review in particular our work on both time- and frequency-domain approaches and give an outlook on how these architectures can be extended to include further signal processing tasks such as equalization. Optically triggered track-and-hold amplifiers are reported with an equivalent jitter below 80 fs rms in a signal frequency range from 20 GHz to 70 GHz. Frequency-domain architectures implementing optical arbitrary waveform measurement up to signal bandwidths of 610 GHz are also shown. Finally, an architecture allowing the deserialization and equalization of PAM4 signals is introduced and modeled for operation in 400 Gb/s links.}}, author = {{Witzens, Jeremy and Drayss, Daniel and Fang, Dengyang and Moscoso Mártir, Alvaro and Müller, Juliana and Weizel, Maxim and Zazzi, Andrea and Freude, Wolfgang and Koos, Christian and Randel, Sebastian and Scheytt, J. Christoph}}, booktitle = {{Electronic-Photonic Integrated Systems for Ultrafast Signal Processing}}, editor = {{Scheytt, J. Christoph and Kress, Christian and Berroth, Manfred and Pachnicke, Stephan and Witzens, Jeremy}}, isbn = {{9783032083395}}, publisher = {{Springer Nature Switzerland}}, title = {{{Ultra-Broadband Photonically Assisted Analog-to-Digital-Converters}}}, doi = {{10.1007/978-3-032-08340-1_3}}, year = {{2026}}, } @inbook{65600, abstract = {{Integrated photonic-assisted signal processing has multiple applications such as signal amplification, multiplexing, and high-Q filtering in optical communication systems, optical sensing systems, and also microwave photonics. We will review recent works on integrated photonic-assisted signal processing for sinc-shaped Nyquist pulse generation, high-bandwidth Nyquist signal detection with low bandwidth devices, arbitrary waveform generation and measurement, and on-chip photonic frequency decoding. However, in such photonic integrated circuits (PICs), the photonic components are placed very close to each other on the chip, resulting in thermal crosstalk which degrades the system performance. Air-filled oxide and deep trench designs have proven to be very effective in mitigating the thermal crosstalk for various frequently deployed photonic devices like Mach-Zehnder modulators (MZMs), ring resonators, optical switches, and photodetectors designed on a standard silicon-on-insulator (SOI) platform. In this chapter, we will additionally review the basics of optical signal processing and some results for such trench-enhanced thermal crosstalk resilient circuits.}}, author = {{De, Souvaraj and Mandalawi, Younus and Das, Ranjan and Weizel, Maxim}}, booktitle = {{Metrology for THz Communications}}, isbn = {{9783032019851}}, issn = {{0342-4111}}, publisher = {{Springer Nature Switzerland}}, title = {{{Integrated Photonic-Assisted Signal Processing and Thermal Crosstalk}}}, doi = {{10.1007/978-3-032-01986-8_20}}, year = {{2026}}, } @inbook{65601, abstract = {{High-speed ADCs operating in the tens of gigahertz up to potentially terahertz range are largely constrained by the jitter in their clock sources. By incorporating photonically assisted samplers that exploit the ultralow jitter of specific mode-locked lasers (MLLs) as analogue ADC frontends, the performance limits of data converters can be pushed to achieve unprecedented levels of accuracy. Continuous advancements in electronic-photonic integration (silicon photonics) are clearing the path for integrating these systems on a chip scale, thereby leading to increased scalability, as well as reduced cost and power consumption.}}, author = {{Weizel, Maxim and Bahmanian, Meysam and Scheytt, J. Christoph}}, booktitle = {{Metrology for THz Communications}}, isbn = {{9783032019851}}, issn = {{0342-4111}}, publisher = {{Springer Nature Switzerland}}, title = {{{Integrated Photonically Assisted Samplers}}}, doi = {{10.1007/978-3-032-01986-8_29}}, year = {{2026}}, } @inbook{65602, abstract = {{This chapter explores the crucial role of simulation and modelling of electronic and photonic components for terahertz (THz) systems. THz-related challenges already begin with setting up the signal generation and sampling parameters and continue with the realistic modelling of the electronic and photonic building blocks. Hereby, photonic components require not only the modelling of the optical signal propagation but also the modelling of the electronic interface in the THz regime. Furthermore, when advancing to the simulation of systems like fully integrated electronic transmit and receive frontends or photonically assisted analogue-to-digital converters (ADCs), it is up to the designer to find a suitable level of abstraction. Size, complexity, and available computational power versus accuracy must be taken into consideration and prioritized against each other.}}, author = {{Wrana, Dominik and Weizel, Maxim and Haussmann, Simon and Bahmanian, Meysam and Kallfass, Ingmar and Scheytt, J. Christoph}}, booktitle = {{Metrology for THz Communications}}, isbn = {{9783032019851}}, issn = {{0342-4111}}, publisher = {{Springer Nature Switzerland}}, title = {{{Simulation and Modelling of Electronic and Photonic Components}}}, doi = {{10.1007/978-3-032-01986-8_36}}, year = {{2026}}, } @inproceedings{65625, author = {{Friesen, Olga and Hölscher, Jonas and Siegmund, Michael B. K. and Claes, Leander and Henning, Bernd}}, title = {{{Experimental and Numerical Investigation of Jump Phenomena in the Frequency Response of Piezoelectric Systems}}}, year = {{2026}}, } @inproceedings{65606, abstract = {{Sound capture by microphone arrays opens the possibility to exploit spatial, in addition to spectral, information for diarization and signal enhancement, two important tasks in meeting transcription. However, there is no one-to-one mapping of positions in space to speakers if speakers move. Here, we address this by proposing a novel joint spatial and spectral mixture model, whose two submodels are loosely coupled by modeling the relationship between speaker and position index probabilistically. Thus, spatial and spectral information can be jointly exploited, while at the same time allowing for speakers speaking from different positions. Experiments on the LibriCSS data set with simulated speaker position changes show great improvements over tightly coupled subsystems.}}, author = {{Meise, Adrian Tobias and Cord-Landwehr, Tobias and Boeddeker, Christoph and Delcroix, Marc and Nakatani, Tomohiro and Haeb-Umbach, Reinhold}}, booktitle = {{ICASSP 2026 - 2026 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)}}, keywords = {{mixture models, meeting processing, diarization, source separation}}, location = {{Barcelona}}, publisher = {{IEEE}}, title = {{{Loose Coupling of Spectral and Spatial Models for Multi-Channel Diarization and Enhancement of Meetings in Dynamic Environments}}}, doi = {{10.1109/icassp55912.2026.11463540}}, year = {{2026}}, } @inproceedings{57866, abstract = {{The theory of Total Function NP (TFNP) and its subclasses says that, even if one is promised an efficiently verifiable proof exists for a problem, finding this proof can be intractable. Despite the success of the theory at showing intractability of problems such as computing Brouwer fixed points and Nash equilibria, subclasses of TFNP remain arguably few and far between. In this work, we define two new subclasses of TFNP borne of the study of complex polynomial systems: Multi-homogeneous Systems (MHS) and Sparse Fundamental Theorem of Algebra (SFTA). The first of these is based on B\'ezout's theorem from algebraic geometry, marking the first TFNP subclass based on an algebraic geometric principle. At the heart of our study is the computational problem known as Quantum SAT (QSAT) with a System of Distinct Representatives (SDR), first studied by [Laumann, L\"auchli, Moessner, Scardicchio, and Sondhi 2010]. Among other results, we show that QSAT with SDR is MHS-complete, thus giving not only the first link between quantum complexity theory and TFNP, but also the first TFNP problem whose classical variant (SAT with SDR) is easy but whose quantum variant is hard. We also show how to embed the roots of a sparse, high-degree, univariate polynomial into QSAT with SDR, obtaining that SFTA is contained in a zero-error version of MHS. We conjecture this construction also works in the low-error setting, which would imply SFTA is contained in MHS.}}, author = {{Aldi, Marco and Gharibian, Sevag and Rudolph, Dorian}}, booktitle = {{17th Innovations in Theoretical Computer Science Conference (ITCS 2026)}}, pages = {{7:1--7:24}}, title = {{{An unholy trinity: TFNP, polynomial systems, and the quantum satisfiability problem}}}, volume = {{362}}, year = {{2026}}, } @article{65631, abstract = {{Abstract Mathematics textbooks used to be the key resource for students’ self-regulated learning of mathematics. Primarily due to the digitalization of society, students have potentially greater access to a wider range of resources such as internet search engines, learning platforms, educational videos, and Generative AI. This study investigates the role of the mathematics textbook in comparison to other resources within students’ self-regulated learning practices. Data were collected via a survey of 1101 German secondary students, representing three school types ( Gymnasium , Gesamtschule , Realschule ) and three grade levels (6, 9, and upper secondary). The questionnaire assessed the frequency of resource use in and outside class, reasons and purposes of use, and resource-based strategies when facing learning challenges outside class. Results show that the printed mathematics textbook is the most frequently used resource both in class and outside class. The textbook remains the most relevant resource for key purposes, such as an aid for doing homework and preparing for tests and exams. However, its dominance diminishes with age: in upper secondary school, students increasingly rely on self-created notes, and online resources. Correlation analyses reveal moderate to strong links between in-class and out-of-class use, suggesting an association between resource use and classroom culture. The findings underscore the textbook’s enduring centrality as a foundational, trusted resource within a dynamic and increasingly diverse learning environment. This study calls for pedagogical approaches that integrate textbooks more intentionally within broader resource systems, supporting students’ agency and strategic resource selection in an era of digital abundance. }}, author = {{Stallmeister, Lea and Rezat, Sebastian}}, issn = {{0013-1954}}, journal = {{Educational Studies in Mathematics}}, keywords = {{mathematics, textbooks, userstudy, resources, digital resources, students, secondary eduction}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{The role of the mathematics textbook in times of resource diversity}}}, doi = {{10.1007/s10649-026-10511-7}}, year = {{2026}}, } @article{65242, abstract = {{With the growing demand for lightweight solutions to reduce emissions, especially in the transportation, automotive and aerospace sectors, recyclable, continuous fiber-reinforced plastic composite laminates with a thermoplastic matrix are of rising interest. To achieve their maximum mechanical properties, the fiber-matrix adhesion (FMA) is critical. In this work, continuous fiber-reinforced thermoplastic laminates (CFRTPL) with a polypropylene (PP) matrix and twill woven glass fiber fabrics are produced by film stacking. The films used contain different amounts of maleic-anhydride-grafted PP (MA-g-PP) as a coupling agent to produce CFRTPL of different mechanical strengths. To analyze the FMA, the CFRTPL are subjected to Charpy-impact and tensile tests. Additionally, single fiber pull-out tests (SFPT) are conducted to further investigate the effect of MA-g-PP on the FMA. The results of the SFPT show an improvement in apparent interfacial shear strength (AIFSS) when the MA-g-PP content is increased, which can be attributed to an increase in FMA. However, the research shows that MA-g-PP has a low impact on the mechanical properties if the force is applied parallel to the warp and weft threads during tensile testing and the results of the Charpy-impact testing suffer from embrittlement of the matrix material. Subsequently, the results of this study are compared to three-point flexural tests conducted in a previous study. It can be concluded that tensile and impact tests are not suited to investigate FMA on a macroscopic scale, while SFPT and flexural tests provide a better alternative.}}, author = {{Moritzer, Elmar and Brandes, Philipp and Wittler, Maurice and Claes, Leander and Wippermann, Mareen and Haag, Markus and Gries, Thomas and Henning, Bernd}}, issn = {{0930-777X}}, journal = {{International Polymer Processing}}, publisher = {{Walter de Gruyter GmbH}}, title = {{{Fiber-matrix adhesion in glass fiber reinforced thermoplastic composite laminates and its effect on mechanical properties}}}, doi = {{10.1515/ipp-2025-0077}}, year = {{2026}}, } @article{65630, abstract = {{Mathematics textbooks used to be the key resource for students’ self-regulated learning of mathematics. Primarily due to the digitalization of society, students have potentially greater access to a wider range of resources such as internet search engines, learning platforms, educational videos, and Generative AI. This study investigates the role of the mathematics textbook in comparison to other resources within students’ self-regulated learning practices. Data were collected via a survey of 1101 German secondary students, representing three school types (Gymnasium, Gesamtschule, Realschule) and three grade levels (6, 9, and upper secondary). The questionnaire assessed the frequency of resource use in and outside class, reasons and purposes of use, and resource-based strategies when facing learning challenges outside class. Results show that the printed mathematics textbook is the most frequently used resource both in class and outside class. The textbook remains the most relevant resource for key purposes, such as an aid for doing homework and preparing for tests and exams. However, its dominance diminishes with age: in upper secondary school, students increasingly rely on self-created notes, and online resources. Correlation analyses reveal moderate to strong links between in-class and out-of-class use, suggesting an association between resource use and classroom culture. The findings underscore the textbook’s enduring centrality as a foundational, trusted resource within a dynamic and increasingly diverse learning environment. This study calls for pedagogical approaches that integrate textbooks more intentionally within broader resource systems, supporting students’ agency and strategic resource selection in an era of digital abundance.}}, author = {{Stallmeister, Lea and Rezat, Sebastian}}, journal = {{Educational Studies in Mathematics}}, publisher = {{Springer}}, title = {{{The role of the mathematics textbook in times of resource diversity}}}, doi = {{10.1007/s10649-026-10511-7}}, year = {{2026}}, } @article{65645, abstract = {{Curriculum material is often designed to address content-specific intended learning goals. However, research indicates that teachers’ personal goals may cause misalignments between their implementation of curriculum material and its intended learning goals. This study aims to investigate misalignments between teachers’ implementation of curriculum material and its intended learning goals and to which extent they are caused by teachers’ personal goals. To reach this aim, a qualitative study was conducted to examine how eight vocational school teachers implemented the learning activity “How many?” suggested for the initial training of early childhood educators on the topic of set perception and determination of cardinality. Each participant provided a lesson plan and self-recorded lesson video on the topic of set perception and determination of cardinality. In addition, participants were interviewed on how they used the provided curriculum material for designing their lessons and their potential reasons to adapt or omit “How many?”. To evaluate their lesson design’s alignment with the activity’s intended learning goals, the participants' lesson plans were analyzed using qualitative content analysis. Triangulation of the findings with the interview data revealed that only one participant fully adopted the intended learning goals as her own and implemented the activity completely in line with its intended learning goals. Meanwhile, the remaining participants’ personal goals, such as reducing math anxiety, seemed to cause misalignments regarding the intended learning goals. The study's results detail further constraints and affordances to the alignment between teachers’ lesson designs and learning goals intended by curriculum material. It is followed that it is central to support teachers in adopting intended learning goals as their personal goals. Otherwise, teachers’ classroom implementation of curriculum material may not suffice to reach desired outcomes.}}, author = {{Richter, Alix and Bruns, Julia}}, issn = {{1306-3030}}, journal = {{International Electronic Journal of Mathematics Education}}, number = {{2}}, publisher = {{Modestum Ltd}}, title = {{{All a question of the goal? Re-tracing (mis)alignments between teachers’ implementations of curriculum material and intended learning goals in the context of early childhood educator training in Germany}}}, doi = {{10.29333/iejme/18564}}, volume = {{21}}, year = {{2026}}, } @inproceedings{65013, author = {{Illian, Marvin and Khalili, Ramin and A. de A. Rocha, Antonio and Wang, Lin}}, booktitle = {{2026 24th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt)}}, publisher = {{IFIP}}, title = {{{Cells on Autopilot: Adaptive Cell (Re)Selection via Reinforcement Learning}}}, year = {{2026}}, } @article{65665, author = {{Ahmadi, Mehdi and Schlosser, Florian and Divkovic, Denis and Meschede, Henning}}, issn = {{2590-1745}}, journal = {{Energy Conversion and Management: X}}, publisher = {{Elsevier BV}}, title = {{{Cost-effective and low-carbon cooling strategies for data centers integrated into wind turbine towers}}}, doi = {{10.1016/j.ecmx.2026.101930}}, volume = {{31}}, year = {{2026}}, }