@article{60050, abstract = {{Reputation systems to rate companies’ performances remain largely unexplored inresearch and are scarcely used in business-to-business (B2B) practice. Such systemsare essential for businesses seeking trustworthy partners, as they help reduce infor-mation asymmetry, lower buyers’ transaction risks, and allow high-quality serviceproviders to justify premium pricing. Unlike traditional review-based systems in thebusiness-to-consumer (B2C) context, we propose a B2B reputation mechanism inwhich buyers commit to a rating payment before a transaction. Once the buyer final-izes the rating, this payment is executed and recorded on a blockchain as an immu-table, secure ledger. Our system mimics natural trust-building mechanisms with rat-ings that are (1) monetary-based, (2) stake-based, (3) non-aggregated, (4) involvecounter-ratings, (5) selectively sellable, (6) individually comparable, (7) stored ona blockchain, (8) and monitored by a third instance. This system provides a novelapproach to fostering trust in B2B transactions by reducing information asymme-try and transaction risk. We illustrate the mechanism’s application in the consultingsector. Our analysis has identified 23 institutional trust and distrust dimensions thatpromote establishing institutional trust through the proposed mechanism. Qualita-tive interviews suggest that, while complex and challenging to apply, this mecha-nism can foster trust in B2B transactions. Given the low maturity in the applicationdomain—rating professional business services with business reputation systems—and solution domain—using monetary stakes for ratings, this system stands as apotential invention.}}, author = {{Hemmrich, Simon and Nissen, Volker and Beverungen, Daniel and Pauls, Josias Daniel Miño}}, journal = {{Information Systems and e-Business Management}}, keywords = {{Information asymmetry, Trust, Reputation system, Monetary rating, Blockchain, Consulting}}, number = {{1}}, publisher = {{Springer}}, title = {{{Blockchain‑based reputation systemsfor business‑to‑business services: designing a reputation mechanism to reduce information asymmetry in professional consulting}}}, doi = {{https://doi.org/10.1007/s10257-025-00702-9}}, volume = {{23}}, year = {{2025}}, } @phdthesis{65309, author = {{Hemmrich, Simon}}, keywords = {{Reputation Systems, Rating systems, monetary ratings, incentive mechanism, systems theory, Market coordination, advanced review system}}, pages = {{347}}, publisher = {{Universität Paderborn}}, title = {{{A Design Theory for Blockchain-Based Reputation Systems : Trust and Coordination in B2B Markets}}}, doi = {{https://doi.org/10.17619/UNIPB/1-2414}}, year = {{2025}}, } @inproceedings{64803, abstract = {{Nowadays ultrasound technology is established in various fields of application like industrial production or medical technology. Besides high power ultrasound applications like ultrasonic cleaning and ultrasonic welding, which are often not strongly restricted regarding their weight, costs, and construction space, there are many applications in the low to medium power range like handheld surgical instruments, medical inhalers, or ultrasonic cutters. For the latter there is often a strong demand for low weight and construction space and low costs to be competitive in mass production. Another challenge that arises from the RoHS-directive [1] is, that new ultrasonic devices should avoid the use of lead-containing PZT-materials. Against this background there is a demand for lead-free, small and lightweight and cost-effective ultrasonic transducers. In many of the above-mentioned applications, pre-stressed Bolted-Langevine-Transducers (BLT) based on lead-containing PZT-materials are established to generate ultrasonic vibrations. These are quite advantageous in many ways and can be built tailored to each application and even for high power of thousands of watts. But due to the required steps during their manufacturing process (machining parts, assembly, pre-stressing, frequency tuning, …), these transducers remain expensive. Furthermore, due to the operation in resonance, the construction space of these transducers is linked to their wavelength and cannot be reduced remarkably. For these reasons, our aim is to present an innovative lead-free ultrasonic transducer for low to medium power applications, that is based on bending vibrations instead of longitudinal vibrations. This design enables to build very small transducers. Furthermore, due to their simple construction, these transducers can be built at low manufacturing costs and are well suited for industrial mass production. The use of lead-free piezoelectric materials makes this transducer design ready for future applications. In our contribution we will present the model-based design of a lead-free 30 kHz bending transducer for applications up to 10 W. Furthermore, the comprehensive experimental analysis of this transducer-prototype in applications like mist generation or ultrasonic drilling will be presented. The results will be compared to a PZT-based bending transducer and a classical BLT to show the potential and limits of these kind of transducers and lead-free materials. }}, author = {{Bornmann, Peter and Littmann, Walter and Scheidemann, Claus and Hemsel, Tobias}}, location = {{Paderborn, Germany}}, title = {{{Innovative lead-free ultrasonic bending transducers for low to medium power applications}}}, year = {{2025}}, } @article{65268, abstract = {{The increasing number of multi-unit hosts in peer-to-peer platforms such as Airbnb poses a significant challenge to single-unit hosts, who compete in a highly professionalized market where host-guest interactions have become increasingly anonymous. However, anonymity may undermine trust and affect eWOM, crucial elements for the performance of peer-to-peer platforms, as they heavily rely on mutual trust and positive eWOM to succeed. This study investigated the effects of the presence of hosts’ personal decorations and a local welcome gift on eWOM. Perceived anonymity and trust emerge as mediating mechanisms, such that the presence of personal decorations reduced the guest’s perception of anonymity towards the host, which subsequently increased guest’s trust and their intention to spread positive eWOM. The local welcome gift did not show any significant effects. These insights contribute to servicescape research and offer practical implications for single-unit hosts to differentiate their service experience from that of professional hosts.}}, author = {{Kring-Ozuna, Edna}}, issn = {{2511-8676}}, journal = {{Journal of Service Management Research}}, number = {{1}}, pages = {{2--18}}, publisher = {{Nomos Verlag}}, title = {{{First impressions matter: Shaping the servicescape to address anonymity and trust in peer-to-peer sharing economy services}}}, doi = {{10.5771/2511-8676-2025-1-2}}, volume = {{9}}, year = {{2025}}, } @misc{64902, abstract = {{Diese Dissertation behandelt die Entwicklung, Erprobung und Evaluation einer mobilen Augmented Reality Anwendung (mAR-App) namens PEARL (Paderborner Elektrotechnik AR Laborpraktikum), die als Vorbereitungsmaßnahme für elektrotechnische Laborpraktika konzipiert wird. Ziel ist es, Studierenden eine zeitlich und örtlich flexible Möglichkeit zu bieten, den realitätsnahen Umgang mit Laborgeräten - primär dem Oszilloskop - zu erlernen. Die methodische Grundlage bilden der Makrozyklus von Design-Based Research (DBR) als strukturierender Rahmen und das heuristische Modell des Research Pentagons, das die Durchführung auf Mikroebene bestimmt. In insgesamt vier Research Pentagons werden didaktische, technologische, motivationale und evaluative Komponenten systematisch untersucht und weiterentwickelt. Das erste Pentagon fokussiert die Entwicklung eines didaktisch fundierten Konzepts nach dem Prinzip des Constructive Alignment, das Lernziele, Lernaktivitäten und Prüfungsformen in fünf abgestufte Lernlevel überführt. Diese reichen von der initialen Orientierung bis zur eigenständigen Problemlösung in einem freien Experimentiermodus. Im zweiten Research Pentagon wird die technische Machbarkeit von Augmented - und Virtual Reality (VR) im Laborumfeld anhand mehrerer funktionaler Prototypen evaluiert. Während sich VR aufgrund technischer Einschränkungen als ungeeignet erweist, zeigt AR - insbesondere in der markerlosen Ausführung mittels der Software Development Kits (SDKs) ARCore und ARKit - ein hohes Potenzial für den praktischen Einsatz. Im dritten Pentagon entsteht ein Onboarding-Modul, das auf die erste Version der mobilen App (V0.17.01) aufsetzt und grundlegende Funktionen eines realen Oszilloskops digital abbildet. Dabei werden Nutzer:innen schrittweise an das virtuelle Oszilloskop herangeführt und lernen zugleich die zentralen Funktionen der mAR-App kennen. Die Ergebnisse zeigen eine insgesamt neutrale bis leicht positive Nutzungserfahrung, wobei technische Schwächen (z.B. Reaktionszeit oder Objektverankerung) die Effizienz und Steuerbarkeit beeinträchtigen. Im Exkurs-Kapitel erfolgt eine Eye-Tracking-Studie zur Untersuchung visueller Aufmerksamkeit und individueller Lösungsstrategien von Expert:innen und Noviz:innen bei der Arbeit am realen Oszilloskop. Heatmaps und Zeitverläufe in definierten Areas of Interest (AOI) liefern erste Hinweise auf Unterschiede im Blickverhalten zwischen den Gruppen. Die algorithmischen Scanpfadanalysen der Blickverläufe hingegen zeigen eine geringe Trennschärfe. Das Potenzial von Eye-Tracking als Evaluationsmethode wird daher kritisch reflektiert, aber angesichts technologischer Entwicklungen und verfügbarer Eye-Tracker in Mixed Reality (MR) Brillen weiterhin als zukunftsrelevant eingeordnet. Die abschließende summative Evaluation nutzt ein Prä‑Post-Test-Design mit Kontrollgruppenvergleich mit 70 Teilnehmenden, um die Lernwirksamkeit der überarbeiteten mAR-App mit klassischen Materialien wie Videos und Handbüchern zu vergleichen. In der Interventionsgruppe (IG) zeigen sich auf kognitiver und affektiver Ebene signifikant positive Veränderungen: Die Leistungen steigen deutlich, insbesondere in den Taxonomiestufen Anwendung, Verständnis und Analyse; zugleich nehmen experimentelles Selbstkonzept und experimentelles Sachinteresse zu, während Überforderung und Ängstlichkeit im Hinblick auf die Laborpraktika abnehmen. Als Einschränkung zeigt sich, dass die mAR-App keinen klaren Vorsprung gegenüber der Kontrollgruppe (KG) erreicht, was sowohl auf die sehr gut ausgearbeiteten Materialien und Videos der KG als auch auf technische Begrenzungen der mobilen Umsetzung zurückzuführen ist: Kleine Displays, 2D-Oberflächen für 3D-Geräte und unpräzise Touch-Interaktionen erschweren komplexe, feinmotorische Aufgaben. In den begleitenden User Interface (UI) und User Experience (UX) Fragebögen spiegeln sich diese Limitationen in gemischten Bewertungen der App wider. Die Arbeit verdeutlicht, dass die mobile AR-Anwendung trotz technischer Einschränkungen wertvolle Möglichkeiten für die Vorbereitung auf Laborpraktika und das Kennenlernen von Laborgeräten bieten kann. Der Fokus bei der Entwicklung liegt von Beginn an auf einer modularen und flexiblen App-Architektur, um sie mit neuen Geräten und Aufgaben zu erweitern. Der Hauptnutzen liegt perspektivisch nicht in der mobilen Anwendung selbst, sondern in der strategischen Ausrichtung auf zukunftsfähige, skalierbare Lösungen für MR-Brillen. Diese erlauben eine authentische Gestensteuerung und realitätsnahe Interaktionen.}}, author = {{Alptekin, Mesut}}, publisher = {{LibreCat University}}, title = {{{Entwicklung einer Augmented Reality basierten Anwendung als Vorbereitungsmaßnahme zum Laborpraktikum in der Elektrotechnik}}}, doi = {{10.17619/UNIPB/1-2483}}, year = {{2025}}, } @misc{63855, abstract = {{Elektronenenergieverlustspektroskopie (engl. EELS) ist eine fortgeschrittene Analysemethode der Transmissionselektronenmikroskopie, die auf atomarer Ebene Einblicke in Materialcharakteristika wie bspw. Eigenschaften des Elektronensystems oder der Materialzusammensetzung erlaubt. Die Genauigkeit jeder EELS-Analyse ist jedoch fundamental durch Rauschen und Unschärfe begrenzt. Diese Thesis beschreibt solche Rauschphänomene im Detail. Vor allem bei strahlempfindlichen Materialien, die kurze Bestrahlzeiten erfordern, aber auch bei Elektron-Materie-Wechselwirkungen mit geringer Auftrittshäufigkeit, ist eine solche Beschreibung notwendig, da das Rauschen solche Messungen dominiert. Zusätzlich spielen Korrelationen des Rauschens eine Rolle, die durch Faltung des verrauschten Signals mit der Punktspreizfunktion des Detektors entstehen und die sowohl theoretisch als auch experimentell beschrieben werden. Methoden zur Messung der wichtigsten Rauschparameter bei typischen Detektorsystemen werden vorgestellt und erlauben es, das Rauschmodel auf jeden beliebigen EELS-Detektor anzupassen. Eine neue Entfaltungsmethode wird vorgeschlagen, die EELS-Messungen schärft und entrauscht. Die Wirksamkeit dieser Methode wird an Simulations- und Experimentaldaten dargelegt. Hierbei wird gezeigt, dass die neue Methode signifikant bessere Ergebnisse liefert, als bisherige und somit eine Analyse von Messdaten auf einem Level ermöglicht, das die Möglichkeiten der Elektronenmikroskopie deutlich erweitert.}}, author = {{Zietlow, Christian}}, publisher = {{Universitätsbibliothek Paderborn}}, title = {{{A novel Lagrangian-based method for the deconvolution of electron energy-loss spectra}}}, doi = {{10.17619/UNIPB/1-2438}}, year = {{2025}}, } @article{63250, abstract = {{Abstract An initial-boundary value problem for $$\begin{aligned} \left\{ \begin{array}{ll}u_{tt} = \big (\gamma (\Theta ) u_{xt}\big )_x + au_{xx} - \big (f(\Theta )\big )_x, \qquad & x\in \Omega , \ t>0, \\[1mm] \Theta _t = \Theta _{xx} + \gamma (\Theta ) u_{xt}^2 - f(\Theta ) u_{xt}, \qquad & x\in \Omega , \ t>0, \end{array} \right. \end{aligned}$$ u tt = ( γ ( Θ ) u xt ) x + a u xx - ( f ( Θ ) ) x , x ∈ Ω , t > 0 , [ 1 m m ] Θ t = Θ xx + γ ( Θ ) u xt 2 - f ( Θ ) u xt , x ∈ Ω , t > 0 , is considered in an open bounded real interval $$\Omega $$ Ω . Under the assumption that $$\gamma \in C^0([0,\infty ))$$ γ ∈ C 0 ( [ 0 , ∞ ) ) and $$f\in C^0([0,\infty ))$$ f ∈ C 0 ( [ 0 , ∞ ) ) are such that $$f(0)=0$$ f ( 0 ) = 0 , and $$k_\gamma \le \gamma \le K_\gamma $$ k γ ≤ γ ≤ K γ as well as $$\begin{aligned} |f(\xi )| \le K_f \cdot (\xi +1)^\alpha \qquad \hbox {for all } \xi \ge 0 \end{aligned}$$ | f ( ξ ) | ≤ K f · ( ξ + 1 ) α for all ξ ≥ 0 with some $$k_\gamma>0, K_\gamma>0, K_f>0$$ k γ > 0 , K γ > 0 , K f > 0 and $$\alpha <\frac{3}{2}$$ α < 3 2 , for all suitably regular initial data of arbitrary size a statement on global existence of a global weak solution is derived. By particularly covering the thermodynamically consistent choice $$f\equiv id$$ f ≡ i d of predominant physical relevance, this appears to go beyond previous related literature which seems to either rely on independence of $$\gamma $$ γ on $$\Theta $$ Θ , or to operate on finite time intervals. }}, author = {{Winkler, Michael}}, issn = {{0044-2275}}, journal = {{Zeitschrift für angewandte Mathematik und Physik}}, number = {{5}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Large-data solutions in one-dimensional thermoviscoelasticity involving temperature-dependent viscosities}}}, doi = {{10.1007/s00033-025-02582-y}}, volume = {{76}}, year = {{2025}}, } @article{63249, abstract = {{Abstract The model $$\begin{aligned} \left\{ \begin{array}{l}u_{tt} = \big (\gamma (\Theta ) u_{xt}\big )_x + au_{xx} - \big (f(\Theta )\big )_x, \\[1mm] \Theta _t = \Theta _{xx} + \gamma (\Theta ) u_{xt}^2 - f(\Theta ) u_{xt}, \end{array} \right. \end{aligned}$$ u tt = ( γ ( Θ ) u xt ) x + a u xx - ( f ( Θ ) ) x , [ 1 m m ] Θ t = Θ xx + γ ( Θ ) u xt 2 - f ( Θ ) u xt , for thermoviscoelastic evolution in one-dimensional Kelvin–Voigt materials is considered. By means of an approach based on maximal Sobolev regularity theory of scalar parabolic equations, it is shown that if $$\gamma _0>0$$ γ 0 > 0 is fixed, then there exists $$\delta =\delta (\gamma _0)>0$$ δ = δ ( γ 0 ) > 0 with the property that for suitably regular initial data of arbitrary size an associated initial boundary value problem posed in an open bounded interval admits a global classical solution whenever $$\gamma \in C^2([0,\infty ))$$ γ ∈ C 2 ( [ 0 , ∞ ) ) and $$f\in C^2([0,\infty ))$$ f ∈ C 2 ( [ 0 , ∞ ) ) are such that $$f(0)=0$$ f ( 0 ) = 0 and $$|f(\xi )| \le K_f \cdot (\xi +1)^\alpha $$ | f ( ξ ) | ≤ K f · ( ξ + 1 ) α for all $$\xi \ge 0$$ ξ ≥ 0 and some $$K_f>0$$ K f > 0 and $$\alpha <\frac{3}{2}$$ α < 3 2 , and that $$\begin{aligned} \gamma _0 \le \gamma (\xi ) \le \gamma _0 + \delta \qquad \hbox {for all } \xi \ge 0. \end{aligned}$$ γ 0 ≤ γ ( ξ ) ≤ γ 0 + δ for all ξ ≥ 0 . This is supplemented by a statement on global existence of certain strong solutions, particularly continuous in both components, under weaker conditions on the initial data. }}, author = {{Winkler, Michael}}, issn = {{1424-3199}}, journal = {{Journal of Evolution Equations}}, number = {{4}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Large-data regular solutions in a one-dimensional thermoviscoelastic evolution problem involving temperature-dependent viscosities}}}, doi = {{10.1007/s00028-025-01144-z}}, volume = {{25}}, year = {{2025}}, } @article{63246, abstract = {{Abstract The hyperbolic-parabolic model $$\begin{aligned} \left\{ \begin{array}{ll} u_{tt} = u_{xx} - \big (f(\Theta )\big )_x, \qquad & x\in \Omega , \ t>0, \\ \Theta _t = \Theta _{xx} - f(\Theta ) u_{xt}, \qquad & x\in \Omega , \ t>0, \end{array} \right. \end{aligned}$$ u tt = u xx - ( f ( Θ ) ) x , x ∈ Ω , t > 0 , Θ t = Θ xx - f ( Θ ) u xt , x ∈ Ω , t > 0 , for the evolution of the displacement variable u and the temperature $$\Theta \ge 0$$ Θ ≥ 0 during thermoelastic interaction in a one-dimensional bounded interval $$\Omega $$ Ω is considered. Whereas the literature has provided comprehensive results on global solutions for sufficiently regular initial data $$(u_0,u_{0t},\Theta _0)=(u,u_t,\Theta )|_{t=0}$$ ( u 0 , u 0 t , Θ 0 ) = ( u , u t , Θ ) | t = 0 when $$f\equiv id$$ f ≡ i d , it seems to have remained open so far how far a solution theory can be built solely on the two fundamental physical principles of energy conservation and entropy nondecrease. The present manuscript addresses this by asserting global existence of weak solutions under assumptions which are energy- and entropy-minimal in the sense of allowing for any initial data $$u_0\in W_0^{1,2}(\Omega )$$ u 0 ∈ W 0 1 , 2 ( Ω ) , $$u_{0t} \in L^2(\Omega )$$ u 0 t ∈ L 2 ( Ω ) and $$0\le \Theta _0\in L^1(\Omega )$$ 0 ≤ Θ 0 ∈ L 1 ( Ω ) , and which apply to arbitrary $$f\in C^1([0,\infty ))$$ f ∈ C 1 ( [ 0 , ∞ ) ) with $$f(0)=0$$ f ( 0 ) = 0 and $$f'>0$$ f ′ > 0 on $$[0,\infty )$$ [ 0 , ∞ ) . }}, author = {{Winkler, Michael}}, issn = {{0944-2669}}, journal = {{Calculus of Variations and Partial Differential Equations}}, number = {{1}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{Rough solutions in one-dimensional nonlinear thermoelasticity}}}, doi = {{10.1007/s00526-025-03170-8}}, volume = {{65}}, year = {{2025}}, } @phdthesis{62717, abstract = {{Diese Dissertation untersucht, wie Menschen Entscheidungen in Interaktionen sowohl mit anderen Personen als auch mit zunehmend verbreiteten algorithmischen Systemen treffen. Unter Einbezug von Erkenntnissen aus der Verhaltensökonomie und der Mensch-Maschine-Interaktion wird analysiert, wie kognitive Limitationen, soziale Präferenzen und Wahrnehmungsverzerrungen das Verhalten in Kontexten von Unehrlichkeit, Empfehlungsumsetzung, Feedbackverarbeitung und Selbsteinschätzung prägen. Vier kontrollierte ökonomische Experimente zeigen, dass algorithmische Intransparenz unehrliches Verhalten verstärken kann, die Einbindung von Nutzern in das Training von KI-Systemen zwar deren Wahrnehmung verbessert, jedoch nicht die tatsächliche Befolgung algorithmischer Ratschläge fördert, dass Echtzeit-Feedback in Human-in-the-Loop-Systemen unbeabsichtigt Verhaltensverzerrungen verstärken kann und dass gängige Messungen von Selbstüberschätzung stark von methodischen Designentscheidungen abhängen. Die Dissertation unterstreicht die Notwendigkeit, realistische Annahmen über menschliches Verhalten bei der Gestaltung von Prüfungsprozessen, Empfehlungssystemen und interaktiven Technologien zu berücksichtigen und leistet damit einen Beitrag zu einem besseren Verständnis menschlicher Entscheidungsprozesse in einer zunehmend automatisierten Welt.}}, author = {{Protte, Marius}}, publisher = {{LibreCat University}}, title = {{{Behavioral effects in human-machine and human-human interactions}}}, doi = {{10.17619/UNIPB/1-2448}}, year = {{2025}}, } @article{65537, abstract = {{It is a widely accepted standard practice to implement cryptographic software so that secret inputs do not influence the cycle count. Software following this paradigm is often referred to as “constant-time” software and typically involves following three rules: 1) never branch on a secret-dependent condition, 2) never access memory at a secret-dependent location, and 3) avoid variable-time arithmetic operations on secret data. The third rule requires knowledge about such variable-time arithmetic instructions, or vice versa, which operations are safe to use on secret inputs. For a long time, this knowledge was based on either documentation or microbenchmarks, but critically, there were never any guarantees for future microarchitectures. This changed with the introduction of the data-operand-independent-timing (DOIT) mode on Intel CPUs and, to some extent, the data-independent-timing (DIT) mode on Arm CPUs. Both Intel and Arm document a subset of their respective instruction sets that are intended to leak no information about their inputs through timing, even on future microarchitectures if the CPU is set to run in a dedicated DOIT (or DIT) mode.In this paper, we present a principled solution that leverages DOIT to enable cryptographic software that is future-proof constant-time, in the sense that it ensures that only instructions from the DOIT subset are used to operate on secret data, even during speculative execution after a mispredicted branch or function return location. For this solution, we build on top of existing security type systems in the Jasmin framework for high-assurance cryptography.We then use our solution to evaluate the extent to which existing cryptographic software built to be “constant-time” is already secure in this stricter paradigm implied by DOIT and what the performance impact is to move from constant-time to future-proof constant-time.}}, author = {{Arranz-Olmos, Santiago and Barthe, Gilles and Grégoire, Benjamin and Jancar, Jan and Laporte, Vincent and Oliveira, Tiago and Schwabe, Peter}}, issn = {{2569-2925}}, journal = {{IACR Transactions on Cryptographic Hardware and Embedded Systems}}, number = {{3}}, pages = {{644--667}}, publisher = {{Universitatsbibliothek der Ruhr-Universitat Bochum}}, title = {{{Let’s DOIT: Using Intel’s Extended HW/SW Contract for Secure Compilation of Crypto Code}}}, doi = {{10.46586/tches.v2025.i3.644-667}}, volume = {{2025}}, year = {{2025}}, } @inproceedings{50272, abstract = {{Despite the fundamental role the Quantum Satisfiability (QSAT) problem has played in quantum complexity theory, a central question remains open: At which local dimension does the complexity of QSAT transition from "easy" to "hard"? Here, we study QSAT with each constraint acting on a $k$-dimensional and $l$-dimensional qudit pair, denoted $(k,l)$-QSAT. Our first main result shows that, surprisingly, QSAT on qubits can remain $\mathsf{QMA}_1$-hard, in that $(2,5)$-QSAT is $\mathsf{QMA}_1$-complete. In contrast, $2$-SAT on qubits is well-known to be poly-time solvable [Bravyi, 2006]. Our second main result proves that $(3,d)$-QSAT on the 1D line with $d\in O(1)$ is also $\mathsf{QMA}_1$-hard. Finally, we initiate the study of 1D $(2,d)$-QSAT by giving a frustration-free 1D Hamiltonian with a unique, entangled ground state. Our first result uses a direct embedding, combining a novel clock construction with the 2D circuit-to-Hamiltonian construction of [Gosset, Nagaj, 2013]. Of note is a new simplified and analytic proof for the latter (as opposed to a partially numeric proof in [GN13]). This exploits Unitary Labelled Graphs [Bausch, Cubitt, Ozols, 2017] together with a new "Nullspace Connection Lemma", allowing us to break low energy analyses into small patches of projectors, and to improve the soundness analysis of [GN13] from $\Omega(1/T^6)$ to $\Omega(1/T^2)$, for $T$ the number of gates. Our second result goes via black-box reduction: Given an arbitrary 1D Hamiltonian $H$ on $d'$-dimensional qudits, we show how to embed it into an effective null-space of a 1D $(3,d)$-QSAT instance, for $d\in O(1)$. Our approach may be viewed as a weaker notion of "simulation" (\`a la [Bravyi, Hastings 2017], [Cubitt, Montanaro, Piddock 2018]). As far as we are aware, this gives the first "black-box simulation"-based $\mathsf{QMA}_1$-hardness result, i.e. for frustration-free Hamiltonians.}}, author = {{Rudolph, Dorian and Gharibian, Sevag and Nagaj, Daniel}}, booktitle = {{16th Innovations in Theoretical Computer Science (ITCS)}}, number = {{85}}, pages = {{1--24}}, title = {{{Quantum 2-SAT on low dimensional systems is $\mathsf{QMA}_1$-complete: Direct embeddings and black-box simulation}}}, doi = {{10.4230/LIPIcs.ITCS.2025.85}}, volume = {{325}}, year = {{2025}}, } @unpublished{61776, abstract = {{We investigate the role of energy, i.e. average photon number, as a resource in the computational complexity of bosonic systems. We show three sets of results: (1. Energy growth rates) There exist bosonic gate sets which increase energy incredibly rapidly, obtaining e.g. infinite energy in finite/constant time. We prove these high energies can make computing properties of bosonic computations, such as deciding whether a given computation will attain infinite energy, extremely difficult, formally undecidable. (2. Lower bounds on computational power) More energy ``='' more computational power. For example, certain gate sets allow poly-time bosonic computations to simulate PTOWER, the set of deterministic computations whose runtime scales as a tower of exponentials with polynomial height. Even just exponential energy and $O(1)$ modes suffice to simulate NP, which, importantly, is a setup similar to that of the recent bosonic factoring algorithm of [Brenner, Caha, Coiteux-Roy and Koenig (2024)]. For simpler gate sets, we show an energy hierarchy theorem. (3. Upper bounds on computational power) Bosonic computations with polynomial energy can be simulated in BQP, ``physical'' bosonic computations with arbitrary finite energy are decidable, and the gate set consisting of Gaussian gates and the cubic phase gate can be simulated in PP, with exponential bound on energy, improving upon the previous PSPACE upper bound. Finally, combining upper and lower bounds yields no-go theorems for a continuous-variable Solovay--Kitaev theorem for gate sets such as the Gaussian and cubic phase gates.}}, author = {{Chabaud, Ulysse and Gharibian, Sevag and Mehraban, Saeed and Motamedi, Arsalan and Naeij, Hamid Reza and Rudolph, Dorian and Sambrani, Dhruva}}, booktitle = {{arXiv:2510.08545}}, title = {{{Energy, Bosons and Computational Complexity}}}, year = {{2025}}, } @unpublished{61778, abstract = {{Understanding the entanglement structure of local Hamiltonian ground spaces is a physically motivated problem, with applications ranging from tensor network design to quantum error-correcting codes. To this end, we study the complexity of estimating ground state entanglement, and more generally entropy estimation for low energy states and Gibbs states. We find, in particular, that the classes qq-QAM [Kobayashi, le Gall, Nishimura, SICOMP 2019] (a quantum analogue of public-coin AM) and QMA(2) (QMA with unentangled proofs) play a crucial role for such problems, showing: (1) Detecting a high-entanglement ground state is qq-QAM-complete, (2) computing an additive error approximation to the Helmholtz free energy (equivalently, a multiplicative error approximation to the partition function) is in qq-QAM, (3) detecting a low-entanglement ground state is QMA(2)-hard, and (4) detecting low energy states which are close to product states can range from QMA-complete to QMA(2)-complete. Our results make progress on an open question of [Bravyi, Chowdhury, Gosset and Wocjan, Nature Physics 2022] on free energy, and yield the first QMA(2)-complete Hamiltonian problem using local Hamiltonians (cf. the sparse QMA(2)-complete Hamiltonian problem of [Chailloux, Sattath, CCC 2012]).}}, author = {{Gharibian, Sevag and Kamminga, Jonas}}, booktitle = {{arXiv:2510.06796}}, title = {{{On the complexity of estimating ground state entanglement and free energy}}}, year = {{2025}}, } @misc{48363, author = {{Foerster, Anne}}, booktitle = {{Women in Early Medieval England}}, editor = {{Butler, Emily and Dumitrescu, Irina}}, publisher = {{Springer Textbook}}, title = {{{The Swineherd’s Wife who Scolded the King}}}, year = {{2024}}, } @misc{48362, author = {{Foerster, Anne}}, booktitle = {{Women in Early Medieval England}}, editor = {{Butler, Emily and Dumitrescu, Irina}}, publisher = {{Springer Textbook}}, title = {{{Eadburh of Wessex}}}, year = {{2024}}, } @misc{48364, author = {{Foerster, Anne}}, booktitle = {{Women in Early Medieval England}}, editor = {{Butler, Emily and Dumitrescu, Irina}}, publisher = {{Springer Textbook}}, title = {{{Seaxburh}}}, year = {{2024}}, } @inbook{41850, author = {{Silvestri, Marco}}, booktitle = {{Bergbau und Hausbau}}, title = {{{Struktur und Sonderbauten der Silberbergbaustädte des 16. Jahrhunderts. Zur Korrelation von Städtebau und Montanwesen (Potosí und das Erzgebirge)}}}, year = {{2024}}, } @phdthesis{50530, abstract = {{Die Extrusion stellt das mengenmäßig dominante Verarbeitungsverfahren für thermoplastische Kunststoffe dar. Daher gibt es starke Bestrebungen in diesem Bereich hin zu einer höheren Wirtschaftlichkeit, welche beispielsweise durch höheren Massedurchsatz bei gleichbleibender Maschinengröße erreicht werden kann, oder aber auch im Hinblick auf eine Kreislaufwirtschaft die Bestrebung hin zu einer materialschonenden Verarbeitung. Beide Bestrebungen erfordern spezielle Schneckenkonzepte. Hierunter fallenWave- Schnecken, welche in beiden Bereichen ein vorteilhaftes Prozessverhalten aufzeigen sollen. Die Auslegung von Wave-Schnecken erfordert jedoch ein stärkeres Verständnis über das geometrieabhängige Prozessverhalten in der Extrusion. Im Rahmen der Dissertation werden zwei Themengebiete angegangen. Das erste Thema ist die Herleitung einer Methode zur Charakterisierung des Abbauverhaltens von Thermoplasten sowie die Nutzung der Charakterisierung als Vorhersagemodell. Das zweite Thema behandelt die Auslegung von Wave-Schnecken basierend auf numerischen Simulationen samt Validierung anhand von sieben Energy-Transfer-Schnecken im Vergleich zu drei konventionellen Schnecken. Hierbei werden unter anderem der Materialabbau, die thermische und die stoffliche Homogenität betrachtet, um ein umfassendes Bild über das Prozessverhalten der Schnecken zu schaffen. Die vorgestellten Untersuchungen dienen schlussendlich zu einer Bestätigung des vorteilhaften Prozessverhaltens von Wave-Schnecken.}}, author = {{Schall, Christoph Wilhelm Theodor}}, isbn = {{978-3-8440-9334-6}}, pages = {{224}}, publisher = {{Shaker Verlag}}, title = {{{Materialschonende Verarbeitung von Thermoplasten auf Wave-Schnecken}}}, volume = {{Band 2/2024}}, year = {{2024}}, } @article{50798, abstract = {{Abstract Background An infection with SARS-CoV-2 can lead to a variety of symptoms and complications, which can impair athletic activity. Objective We aimed to assess the clinical symptom patterns, diagnostic findings, and the extent of impairment in sport practice in a large cohort of athletes infected with SARS-CoV-2, both initially after infection and at follow-up. Additionally, we investigated whether baseline factors that may contribute to reduced exercise tolerance at follow-up can be identified. Methods In this prospective, observational, multicenter study, we recruited German COVID elite-athletes (cEAs, n = 444) and COVID non-elite athletes (cNEAs, n = 481) who tested positive for SARS-CoV-2 by PCR (polymerase chain reaction test). Athletes from the federal squad with no evidence of SARS-CoV-2 infection served as healthy controls (EAcon, n = 501). Questionnaires were used to assess load and duration of infectious symptoms, other complaints, exercise tolerance, and duration of training interruption at baseline and at follow-up 6 months after baseline. Diagnostic tests conducted at baseline included resting and exercise electrocardiogram (ECG), echocardiography, spirometry, and blood analyses. Results Most acute and infection-related symptoms and other complaints were more prevalent in cNEA than in cEAs. Compared to cEAs, EAcon had a low symptom load. In cNEAs, female athletes had a higher prevalence of complaints such as palpitations, dizziness, chest pain, myalgia, sleeping disturbances, mood swings, and concentration problems compared to male athletes (p < 0.05). Until follow-up, leading symptoms were drop in performance, concentration problems, and dyspnea on exertion. Female athletes had significantly higher prevalence for symptoms until follow-up compared to male. Pathological findings in ECG, echocardiography, and spirometry, attributed to SARS-CoV-2 infection, were rare in infected athletes. Most athletes reported a training interruption between 2 and 4 weeks (cNEAs: 52.9%, cEAs: 52.4%), while more cNEAs (27.1%) compared to cEAs (5.1%) had a training interruption lasting more than 4 weeks (p < 0.001). At follow-up, 13.8% of cNEAs and 9.9% of cEAs (p = 0.24) reported their current exercise tolerance to be under 70% compared to pre-infection state. A persistent loss of exercise tolerance at follow-up was associated with persistent complaints at baseline, female sex, a longer break in training, and age > 38 years. Periodical dichotomization of the data set showed a higher prevalence of infectious symptoms such as cough, sore throat, and coryza in the second phase of the pandemic, while a number of neuropsychiatric symptoms as well as dyspnea on exertion were less frequent in this period. Conclusions Compared to recreational athletes, elite athletes seem to be at lower risk of being or remaining symptomatic after SARS-CoV-2 infection. It remains to be determined whether persistent complaints after SARS-CoV-2 infection without evidence of accompanying organ damage may have a negative impact on further health and career in athletes. Identifying risk factors for an extended recovery period such as female sex and ongoing neuropsychological symptoms could help to identify athletes, who may require a more cautious approach to rebuilding their training regimen. Trial Registration Number DRKS00023717; 06.15.2021—retrospectively registered. }}, author = {{Widmann, Manuel and Gaidai, Roman and Schubert, Isabel and Grummt, Maximilian and Bensen, Lieselotte and Kerling, Arno and Quermann, Anne and Zacher, Jonas and Vollrath, Shirin and Bizjak, Daniel Alexander and Beckendorf, Claudia and Egger, Florian and Hasler, Erik and Mellwig, Klaus-Peter and Fütterer, Cornelia and Wimbauer, Fritz and Vogel, Azin and Schoenfeld, Julia and Wüstenfeld, Jan C. and Kastner, Tom and Barsch, Friedrich and Friedmann-Bette, Birgit and Bloch, Wilhelm and Meyer, Tim and Mayer, Frank and Wolfarth, Bernd and Roecker, Kai and Reinsberger, Claus and Haller, Bernhard and Niess, Andreas M. and Birnbaum, Mike Peter and Burgstahler, Christof and Cassel, Michael and Deibert, Peter and Esefeld, Katrin and Erz, Gunnar and Greiss, Franziska and Halle, Martin and Hesse, Judith and Keller, Karsten and Kopp, Christine and Matits, Lynn and Predel, Hans Georg and Rüdrich, Peter and Schneider, Gerald and Stapmanns, Philipp and Steinacker, Jürgen Michael and Szekessy, Sarah and Venhorst, Andreas and Zapf, Stephanie and Zickwolf, Christian}}, issn = {{0112-1642}}, journal = {{Sports Medicine}}, keywords = {{Physical Therapy, Sports Therapy and Rehabilitation, Orthopedics and Sports Medicine}}, publisher = {{Springer Science and Business Media LLC}}, title = {{{COVID-19 in Female and Male Athletes: Symptoms, Clinical Findings, Outcome, and Prolonged Exercise Intolerance—A Prospective, Observational, Multicenter Cohort Study (CoSmo-S)}}}, doi = {{10.1007/s40279-023-01976-0}}, year = {{2024}}, }