cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Predicting processing times in high mix low volume job shops
Creators: name: Müller, Anna
name: Grumbach, Felix
Publisher: name: Otto von Guericke University Library, Magdeburg, Germany
Year: 2023
Subjects: subject: Production planning
subject: ERP
subject: Machine learning (ML)
subject: 620

description: Production planning is essential for any manufacturing company, especially when complex and varied processes must be considered. Accurate processing times play a critical role for scheduling production runs and allocating resources effectively. In practice, the respective master data from the ERP system is often used for this purpose. However, maintaining the master data is challenging, especially with large amounts of data in flexible environments. In this context, incorrect or outdated data quickly lead to significant planning inaccuracies. This paper presents a study that uses machine learning (ML) models to accurately predict the processing times of single operations of future production runs based on historical production runs. Various ML algorithms were trained and evaluated on a real-world dataset. In comparison to the master data the root mean squared error could be reduced by 23% using ML. Thus, these estimated times can be used for optimizing future schedules and incorporating such an ML model in the production planning process eliminates the need for master data.
Which abelian tensor categories are geometric?
Creators: name: Schäppi, Daniel
Publisher: name: arXiv
Year: 2013
Subjects: subject: Algebraic Geometry (math.AG)
subject: Category Theory (math.CT)
subject: FOS: Mathematics
subject: 14A20, 18D10, 18E15

description: For a large class of geometric objects, the passage to categories of quasi-coherent sheaves provides an embedding in the 2-category of abelian tensor categories. The notion of weakly Tannakian categories introduced by the author gives a characterization of tensor categories in the image of this embedding. However, this notion requires additional structure to be present, namely a fiber functor. For the case of classical Tannakian categories in characteristic zero, Deligne has found intrinsic properties - expressible entirely within the language of tensor categories - which are necessary and sufficient for the existence of a fiber functor. In this paper we generalize Deligne's result to weakly Tannakian categories in characteristic zero. The class of geometric objects whose tensor categories of quasi-coherent sheaves can be recognized in this manner includes both the gerbes arising in classical Tannaka duality and more classical geometric objects such as projective varieties over a field of characteristic zero. Our proof uses a different perspective on fiber functors, which we formalize through the notion of geometric tensor categories. A second application of this perspective allows us to describe categories of quasi-coherent sheaves on fiber products.
description: 42 pages. Improved exposition; version accepted for publication in Crelle's Journal
Redundancy-aware Transformer for Video Question Answering
Creators: name: Li, Yicong
name: Yang, Xun
name: Zhang, An
name: Feng, Chun
name: Wang, Xiang
name: Chua, Tat-Seng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: This paper identifies two kinds of redundancy in the current VideoQA paradigm. Specifically, the current video encoders tend to holistically embed all video clues at different granularities in a hierarchical manner, which inevitably introduces \textit{neighboring-frame redundancy} that can overwhelm detailed visual clues at the object level. Subsequently, prevailing vision-language fusion designs introduce the \textit{cross-modal redundancy} by exhaustively fusing all visual elements with question tokens without explicitly differentiating their pairwise vision-language interactions, thus making a pernicious impact on the answering. To this end, we propose a novel transformer-based architecture, that aims to model VideoQA in a redundancy-aware manner. To address the neighboring-frame redundancy, we introduce a video encoder structure that emphasizes the object-level change in neighboring frames, while adopting an out-of-neighboring message-passing scheme that imposes attention only on distant frames. As for the cross-modal redundancy, we equip our fusion module with a novel adaptive sampling, which explicitly differentiates the vision-language interactions by identifying a small subset of visual elements that exclusively support the answer. Upon these advancements, we find this \underline{R}edundancy-\underline{a}ware trans\underline{former} (RaFormer) can achieve state-of-the-art results on multiple VideoQA benchmarks.
description: Accepted to ACM MM23
Determination of asymmetric information in multistage agricultural Supply Chains: a sequence of research activity
Creators: name: Mardenli, Abdulaziz
name: Sackmann, Dirk
Publisher: name: Otto von Guericke University Library, Magdeburg, Germany
Year: 2023
Subjects: subject: Agricultural supply chains
subject: 620

description: Due to the increasing globalization and the resulting emergence of new market participants, the issue of information asymmetries is of immense importance. Based on globalization, increasingly complex network supply chains are emerging in which information transparency between the actors is insufficiently pronounced. The occurrence of information asymmetry (IA) is particularly pronounced in agricultural supply chains, where different types and sizes of actors, such as small farmers, large producers, or small retailers etc., are involved in the supply chain. The insufficient information transparency in the food value chain, is the result of IA, which leads to mistrust between the actors involved and ultimately to opportunistic behavior among the actors. In this regard, it was of utmost necessity to identify, define and reduce the IA in food supply chains between the actors. The aim of the research project will be to extend the current state of knowledge regarding the topic of information asymmetries by defining variables influencing asymmetric information and calculating information asymmetries. To be able to achieve the goal of the research project, quantitative (e.g., surveys) and qualitative (e.g., expert interviews) empirical methods were used. Prior to this, an extensive literature review was undertaken to identify possible variables influencing asymmetric information, which also served as a basis for the quantitative and qualitative analysis in which the entire supply chain, starting from the seed producer to the end customer, was considered. In the course of this, "neutral actors" such as consulting companies, agricultural cooperatives and food networks were also consulted. They were able to provide extensive insight into possible variables influencing information asymmetry. Through the presentation of the research gap as well as the definition of these variables a comprehensive influencing variables model could finally be created. Furthermore, essential future research actions such as the explorative investigation of variables influencing information asymmetry and a possible IA calculation method, which could be useful, were roughly outlined. In conclusion the topic of information asymmetries in food value chains is highly complex, but this research project allows us to structure IA and make it more informative (or: accessible) for science.
Irreversible thermodynamics of open chemical networks I: Emergent cycles and broken conservation laws
Creators: name: Polettini, Matteo
name: Esposito, Massimiliano
Publisher: name: arXiv
Year: 2014
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Molecular Networks (q-bio.MN)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: In this and a companion paper we outline a general framework for the thermodynamic description of open chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks "in a box", whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulated by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated to nonvanishing affinities, whose symmetries are dictated by the breakage of conservation laws. These central results are resumed in the relation $a + b = s^Y$ between the number of fundamental affinities $a$, that of broken conservation laws $b$ and the number of chemostats $s^Y$. We decompose the steady state entropy production rate in terms of fundamental fluxes and affinities in the spirit of Schnakenberg's theory of network thermodynamics, paving the way for the forthcoming treatment of the linear regime, of efficiency and tight coupling, of free energy transduction and of thermodynamic constraints for network reconstruction.
description: 18 pages
Balik Scientist Program (BSP) and the Return of Filipinos Educated Abroad
Creators: name: Inero Ancho
name: Sae-Hoon Park
Publisher: name: Silpakorn University Research and Development Institute
Year: 2018
Subjects: Balik Scientist Program
brain gain
international education
policy studies
study abroad

description: Humanities, Arts and Social Sciences Studies, 18, 3, 809-822
Microscopic prediction of skyrmion lattice state in clean interface superconductors
Creators: name: Agterberg, Daniel F.
name: Babaev, Egor
name: Garaud, Julien
Publisher: name: arXiv
Year: 2014
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: When an in-plane field is applied to a clean interface superconductor, a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)-like phase is stabilized. This phase has a $\mathrm{U}(1)\times\mathrm{U}(1)$ symmetry and, in principle, this symmetry allows for flux carrying topological excitations different from Abrikosov vortices (which are the simplest defects associated with $S^1 \to S^1$ maps). However, in practice, largely due to electromagnetic and other intercomponent interactions, such topological excitations are very rare in superconducting systems. Here we demonstrate that a realistic microscopic theory for interface superconductors, such as SrTiO$_3$/LaAlO$_3$, predicts an unconventional magnetic response where the flux-carrying objects are skyrmions, characterized by homotopy invariants of $S^2 \to S^2$ maps. Additionally, we show that this microscopic theory predicts that stable fractional vortices form near the boundary of these superconductors. It also predicts the appearance of type-1.5 superconductivity for some range of parameters. Central to these results is the assumption that the Rashba spin orbit coupling is much larger than the superconducting gap.
description: Replaced with a version in print in Phys. Rev. B; Improved and extended as compared to the first version; 10 pages, 6 figures
Test method for the optimal choice of packaging systems
Creators: name: Matyi, Henriett
name: Tamás, Péter
Publisher: name: Otto von Guericke University Library, Magdeburg, Germany
Year: 2023
Subjects: subject: Packaging system
subject: Logistics processes
subject: 620

description: This publication discusses the importance of selecting the most suitable packaging system for companies’ logistics processes. This is a valid social and corporate expectation, as it can reduce environmental impact and improve the efficiency of logistics processes, which are key factors in a company’s competitiveness. The appropriate packaging system can be selected based on experience, but there is a lack of integrated methods that can help choose the right packaging system. The publication proposes an innovative packaging system based on corporate needs. This can also improve the efficiency of sustainable supply chain processes. Packaging systems have an impact on the total cost and operational efficiency of the process.
Acoustic Higher-Order Weyl Semimetal with Bound Hinge States in the Continuum
Creators: name: Pu, Zhenhang
name: He, Hailong
name: Luo, Licheng
name: Ma, Qiyun
name: Ye, Liping
name: Ke, Manzhu
name: Liu, Zhengyou
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Higher-order topological phases have raised widespread interest in recent years with the occurrence of the topological boundary states of dimension two or more less than that of the system bulk. The higher-order topological states have been verified in gapped phases, in a wide variety of systems, such as photonic and acoustic systems, and recently also observed in gapless semimetal phase, such as Weyl and Dirac phases, in systems alike. The higher-order topology is signaled by the hinge states emerging in the common bandgaps of the bulk states and the surface states. In this Letter, we report our first prediction and observation of a new type of hinge states, the bound hinge states in the continuum (BHICs) bulk band, in a higher-order Weyl semimetal implemented in phononic crystal. In contrast to the hinge state in gap, which is characterized by the bulk polarization, the BHIC is identified by the nontrivial surface polarization. The finding of the topological BHICs broadens our insight to the topological states, and may stimulate similar researches in other systems such as electronic, photonic, and cold atoms systems. Our work may pave the way toward high-Q acoustic devices in application.
Mirror-NeRF: Learning Neural Radiance Fields for Mirrors with Whitted-Style Ray Tracing
Creators: name: Zeng, Junyi
name: Bao, Chong
name: Chen, Rui
name: Dong, Zilong
name: Zhang, Guofeng
name: Bao, Hujun
name: Cui, Zhaopeng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Recently, Neural Radiance Fields (NeRF) has exhibited significant success in novel view synthesis, surface reconstruction, etc. However, since no physical reflection is considered in its rendering pipeline, NeRF mistakes the reflection in the mirror as a separate virtual scene, leading to the inaccurate reconstruction of the mirror and multi-view inconsistent reflections in the mirror. In this paper, we present a novel neural rendering framework, named Mirror-NeRF, which is able to learn accurate geometry and reflection of the mirror and support various scene manipulation applications with mirrors, such as adding new objects or mirrors into the scene and synthesizing the reflections of these new objects in mirrors, controlling mirror roughness, etc. To achieve this goal, we propose a unified radiance field by introducing the reflection probability and tracing rays following the light transport model of Whitted Ray Tracing, and also develop several techniques to facilitate the learning process. Experiments and comparisons on both synthetic and real datasets demonstrate the superiority of our method. The code and supplementary material are available on the project webpage: https://zju3dv.github.io/Mirror-NeRF/.
description: Accepted to ACM Multimedia 2023. Project Page: https://zju3dv.github.io/Mirror-NeRF/
A Roadmap for a DCAT-AP Extension
Creators: name: Scrocca, Mario
name: Comerio, Marco
name: Azzini, Antonia
Publisher: name: Zenodo
Year: 2022
Subjects: dcat-ap
metadata profile
metadata specification
extension

description: A roadmap for the definition, implementation and publication of a metadata specification extending DCAT-AP. The roadmap generalizes the approach described in the paper "Towards napDCAT-AP: Roadmap and Requirements for a Transportation Metadata Specification" (https://ceur-ws.org/Vol-3235/paper22.pdf) and has been considered as the reference roadmap in TANGENT for the definition of the tangentDCAT-AP metadata profile (as described in the TANGENT deliverable D2.2 "Data-sharing Governance Model"). This upload is composed of a textual document and a diagram describing the roadmap.
description: This activity was partially supported by the NAPCORE project, co-funded by the European Commission's Directorate General for Transport and Mobility under Grant Agreement no. MOVE/B4/SUB/2020-123/SI2.85223, and the TANGENT project, co-funded from the European Union's Horizon 2020 research and innovation programme under Grant Agreement no. 955273.
Mass-radius relation of strongly magnetized white dwarfs: nearly independent of Landau quantization
Creators: name: Bera, Prasanta
name: Bhattacharya, Dipankar
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We compute static equilibria of white dwarf stars containing strong poloidal magnetic field, and present the modification of white dwarf mass-radius relation caused by the magnetic field. We find that a maximum white dwarf mass of about $1.9$~$M\odot$ may be supported if the interior field is as strong as approximately $10^{10}$ T. This mass is over 30 per cent larger than the traditional Chandrasekhar Limit. The equation of state of electron degenerate matter can be strongly modified due to Landau quantization at such high magnetic fields. We find, however, that this does not significantly affect the structure of the white dwarf.
description: 8 pages, 8 figures
Stress intensity factor interaction between two semi-elliptical cracks in thin-walled cylinder
Creators: name: Behseresht, Saeed
name: Mehdizadeh, Mehdi
Publisher: name: figshare
Year: 2023
Subjects: Solid mechanics

description: Stress intensity factor interaction between two semi-elliptical cracks on the internal surface of internally pressurized cylinder has been examined in Ansys Workbench. A wide range of cracks with different configurations were considered and their interaction effect on each other was investigated. Results show that, when two cracks approach, stress intensity factor increases dramatically along the crack front, especially on surface points. Since, surface points are critical in semi-elliptical surface cracks, interaction between surface defects can cause unexpected fracture. Besides, as far as the distance between cracks is more than the cylinder’s thickness (d>t) or exceeds two times the crack length (d>2c), interaction between flaws can be ignored and two cracks have no influence on each other. Furthermore, two interacting deep cracks create more severe condition than two surface cracks. This means that a larger a/t exacerbates the interaction effect between cracks and results in higher stress intensity factor interaction. Stress corrosion cracking (SCC) and fatigue loading (whether thermal or mechanical) that are inevitable in pressure vessels create such deep cracks. This means that deep adjacent cracks are more probable in pressure vessels and should be considered in order to prevent failure.
Collaborative framework in Cuban food supply chains
Creators: name: Romero, Yalili Rodríguez
name: Ledon, Rene Abreu
name: Coello Machado, Norge Isaias
name: Glistau, Elke
Publisher: name: Otto von Guericke University Library, Magdeburg, Germany
Year: 2023
Subjects: subject: Supply chains (SC)
subject: The Ladov technique
subject: 620

description: As a consequence of the COVID-19 pandemic, supply chains (SC) were interrupted, causing disruptions in the supply and demand of products. Food SCs in Cuba are also affected by high prices and limited integration among their activities. Specifically, the food SC of the basic food basket, which is the object of analysis of this paper. Moreover, the SC do not have a collaborative framework to manage the chain in the face of the impact of disruptions and make it more resilient. Therefore, the objectives of this research are: creating a collaborative framework that allows for integrated work in the SC of multiple companies. We also studied the papers that has been conducted in Cuba on this topic, their commonalities and limitations. The main contribution of this research is a methodology for the creation of a collaborative framework in the SC analyzed that enables integrated work and improves the resilience of the SC. To this end, the proposed methodology is subjected to the analysis of a group of experts using The Iadov technique. Subsequently, the overall satisfaction index is calculated, resulting in a level of 0.86%. With this work, it is possible to initiate the implementation of a collaborative framework for integrated work and increased resilience in the food SC analyzed. However, the effective application of this methodology requires the development of TIC platform and the training of its working personnel.
Les effets du transfert de technologie via les IDE sur la performance des exportations : Cas de l'industrie automobile marocaine
Creators: name: ELKHIDER Abdelkader
name: KISSAI Asmaa
Publisher: name: Zenodo
Year: 2023

description: Le transfert de technologie via les investissements directs étrangers représente un mécanisme par lequel des connaissances et compétences techniques sont partagées entre l'investisseur étranger et les entreprises du pays d'accueil. Ce transfert technologique pratique un effet positif sur la performance à l'exportation, et ce à travers l'optimisation de la qualification de la main d'œuvre locale qui permet l'amélioration de la qualité et de la diversité des produits destinés à l'export. Dans le cadre de ce travail de recherche, nous avons analysé le rôle joué par les investissements directs étrangers dans le développement des exportations du pays d'hôte en s'appuyant sur le transfert technologique. À cette fin, nous avons diagnostiqué les exportations de l'industrie automobile marocaine. 
Cette étude a pu conclure que le transfert de technologie provenant d'un investissement direct étranger aide à la stimulation des exportations de la globalité du secteur.
IAP Studie 2023 - Hybrides Arbeiten : der flexible Mensch in der Arbeitswelt 4.0
Creators: name: Majkovic, Anna-Lena
name: Gundrum, Ellen
name: Werkmann-Karcher, Birgit
name: Kornfeind, Julia Maria
name: Bieri, Seraphina
Publisher: name: ZHAW Zürcher Hochschule für Angewandte Wissenschaften
Year: 2023
Subjects: New Work
Hybrides Arbeiten
Digitalisierung
Post-Covid
Zukunft der Arbeit
Arbeitsorganisation
158: Angewandte Psychologie
331: Arbeitsökonomie

description: Nach den Home-Office-Erfahrungen der letzten Jahre wollen Mitarbeitende nicht mehr im selben Mass wie zuvor an ihre Schreibtische im Unternehmen zurückkehren. Das Home-Office ist eine attraktive Alternative, die sich bewährt hat.
Die IAP Studie 2023 befasst sich mit den Auswirkungen von hybridem Arbeiten auf den Menschen. Im Fokus stehen Themen wie Teamzusammenhalt, die Bindung an das Unternehmen und Innovationsprozesse. Wie erleben Fach- und Führungskräfte hybrides Arbeiten? Inwiefern verändert sich die Zusammenarbeit durch hybrides Arbeiten und welche Herausforderungen bringt das mit sich? Erfahren Sie mehr in unserem ausführlichen Studienbericht.
Some Infinite Dimensional Representations of Reductive Groups with Frobenius Maps
Creators: name: Xi, Nanhua
Publisher: name: arXiv
Year: 2013
Subjects: subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 20C07, 22E99

description: In this paper we construct certain irreducible infinite dimensional representations of algebraic groups with Frobenius maps. In particular, a few classical results of Steinberg and Deligne & Lusztig on complex representations of finite groups of Lie type are extended to reductive algebraic groups with Frobenius maps.
description: 25 pages
Semiclassical spin-spin dynamics and feedback control in transport through a quantum dot
Creators: name: Mosshammer, Klemens
name: Brandes, Tobias
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present a theory of magnetotransport through an electronic orbital, where the electron spin interacts with a (sufficiently) large external spin via an exchange interaction. Using a semiclassical approximation, we derive a set of equations of motions for the electron density matrix and the mean value of the external spin that turns out to be highly nonlinear. The dissipation via the electronic leads is implemented in terms of a quantum master equation that is combined with the nonlinear terms of the spin-spin interaction. With an anisotropic exchange coupling a variety of dynamics is generated, such as self-sustained oscillations with parametric resonances or even chaotic behavior. Within our theory we can integrate a Maxwell-demon-like closed-loop feedback scheme that is capable of transporting particles against an applied bias voltage and that can be used to implement a spin filter to generate spin-dependent oscillating currents of opposite directions.
description: 21 pages, 10 figures, comments are welcome, published in PRB
D3.6 System architecture
Creators: name: Ioana Andreea Ștefan, Antoniu Ștefan
Publisher: name: Zenodo
Year: 2019
Subjects: game-based learning, game-based education

description: Deliverable 3.6 System architecture builds upon the outcomes of D3.3 Learning environment system specification, D3.4 Interface design specification, D3.5 Game design document, and D4.6 Game analytics and adaptation component design. The document details the work carried out by Beaconing partners in Task 3.5 Infrastructure, architecture and systems specification, as well as in undergoing WP4 tasks, informing and supporting the development processes. The document describes the core Beaconing components and their architectures: the Core services; the Personal data store; the Beacon repository; the location context; the Game plot Editor; the Gamified lesson path runtime: the Mini game runtime: the Authoring tool interface; the Procedural content generation; the Game deployment; the User interface; the Learning analytics data store; the Learning analytics services; and the Learning analytics reporting. The document presents the Beaconing Platform overview and how these components are integrated and interact on the Beaconing Platform. The usage scenarios presented herein concern the Game Plot authoring; the Gamified Lesson Path authoring; the User Interface; the Procedural Content Generation; the Game deployment and runtime; Analytics collection. The Beaconing back-end services are detailed, with special attention being given to personal data management.
Anomalous interference in Aharonov-Bohm rings with two Majorana bound states
Creators: name: Ueda, Akiko
name: Yokoyama, Takehito
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We investigate the conductance of an Aharonov-Bohm (AB) interferometer coupled to a quantum dot and two Majorana bound states on the edge of the topological superconductor with finite length. When the tunnel couplings between the Majorana bound states and the Aharonov-Bohm interferometer are fixed to the specific phase, the differential conductance becomes zero irrespective of all the parameters as long as the hoppings to the two Majorana fermions on the opposite side are equal. The conductance at the zero bias voltage does not change with the magnetic flux penetrating the ring for all cases. When the energy level of the quantum dot is equal to the energy of the Majorana bound states, the AB oscillation shows πperiodicity due to the particle-hole symmetry. The breaking of the time-reversal symmetry of the topological superconductor results in 2πperiodicity of the AB oscillation for the specific phase of the tunnel coupling while the time-reversal symmetry breaking leads to the mixing of the triplet and singlet states in the quantum dot in another specific phase.
description: 5 pages, 4 figures
The relative sizes of sumsets and difference sets
Creators: name: Staps, Merlijn
Publisher: name: arXiv
Year: 2014
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: Let A be a finite subset of a commutative additive group Z. The sumset and difference set of A are defined as the sets of pairwise sums and differences of elements of A, respectively. The well-known inequality $σ(A)^{1/2} \leq δ(A) \leq σ(A)^2,$ where $σ(A)=\frac{|A+A|}{|A|}$ is the doubling constant of A and $δ(A)=\frac{|A-A|}{|A|}$ is the difference constant of A, relates the relative sizes of the sumset and difference set of A. The exponent 2 in this inequality is known to be optimal, for the exponent 1/2 this is unknown. We determine those sets for which equality holds in the above inequality. We find that equality holds if and only if A is a coset of some finite subgroup of Z or, equivalently, if and only if both the doubling constant and difference constant are equal to 1. This implies that there is space for possible improvement of the exponent 1/2 in the inequality. We then use the derived methods to show that Plünnecke's inequality is strict when the doubling constant is larger than 1.
description: typos corrected; references updated
Zitterbewegung of electrons in carbon nanotubes created by laser pulses
Creators: name: Rusin, Tomasz M
name: Zawadzki, Wlodek
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We describe a possibility of creating non-stationary electron wave packets in zigzag carbon nanotubes (CNT) illuminated by short laser pulses. After disappearance of the pulse the packet experiences the trembling motion (Zitterbewegung, ZB). The band structure of CNT is calculated using the tight-binding approximation generalized for the presence of radiation. Employing realistic pulse and CNT parameters we obtain the ZB oscillations with inter-band frequencies corresponding to specific pairs of energy bands. A choice of optimal parameters is presented in order to observe the phenomenon of ZB experimentally. The use of Gaussian wave packets to trigger the electron Zitterbewegung, as used in the literature, is critically reexamined.
description: 22 pages, 9 figures, IOP format, published version in two-column form
GPU Optimization of Lattice Boltzmann Method with Local Ensemble Transform Kalman Filter
Creators: name: Hasegawa, Yuta
name: Imamura, Toshiyuki
name: Ina, Takuya
name: Onodera, Naoyuki
name: Asahi, Yuuichi
name: Idomura, Yasuhiro
Publisher: name: arXiv
Year: 2023
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: The ensemble data assimilation of computational fluid dynamics simulations based on the lattice Boltzmann method (LBM) and the local ensemble transform Kalman filter (LETKF) is implemented and optimized on a GPU supercomputer based on NVIDIA A100 GPUs. To connect the LBM and LETKF parts, data transpose communication is optimized by overlapping computation, file I/O, and communication based on data dependency in each LETKF kernel. In two dimensional forced isotropic turbulence simulations with the ensemble size of $M=64$ and the number of grid points of $N_x=128^2$, the optimized implementation achieved $\times3.80$ speedup from the naive implementation, in which the LETKF part is not parallelized. The main computing kernel of the local problem is the eigenvalue decomposition (EVD) of $M\times M$ real symmetric dense matrices, which is computed by a newly developed batched EVD in $\verb|EigenG|$. The batched EVD in $\verb|EigenG|$ outperforms that in $\verb|cuSOLVER|$, and $\times65.3$ speedup was achieved.
Beyond generalists: the Brassicaceae pollen specialist Osmia brevicornis as a prospective model organism when exploring pesticide risk to bees
Creators: name: Hellström, Sara
name: Strobl, Verena
name: Straub, Lars
name: Osterman, Wilhelm
name: Paxton, Robert
name: Osterman, Julia
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2023
Subjects: subject: Ecotoxicology
subject: Solitary bee
subject: Method development
subject: Oilseed rape
subject: Pollen contamination
subject: Risk assessment
subject: Pollinator conservation
subject: DDC::5** Naturwissenschaften und Mathematik::57* Biowissenschaften; Biologie::577 Ökologie
subject: DDC::5** Naturwissenschaften und Mathematik::59* Tiere (Zoologie)::595 Arthropoden (Gliederfüßer)

description: Bees are under threat from agricultural intensification, and species which are pollen specialists (oligolectic) are thought to have declined disproportionately compared to pollen generalists (polylectic). When assessing the risks of dietary pesticide (plant protection products) exposure to non-target beneficial insects such as wild bees, effects on pollen specialist species have seldom been considered. Research and risk assessment on pesticide risk to bees mainly use a small selection of model species, only representing pollen generalist species. Moreover, the foraging preferences of the existing model species are not always adequately matched to the crops investigated, which may lead to incorrect conclusions regarding the risks posed by pesticides in pollen and nectar. Here, we propose Osmia brevicornis, an oligolectic European wild bee species specialized on Brassicaceae pollen, as a new model organism suitable for assessment of how pesticides can impact specialist pollinators, especially in oilseed rape, a mass flowering Brassicaceae crop. We demonstrate that O. brevicornis can be successfully reared in the field next to oilseed rape and that its nesting success and offspring numbers can be increased by setting out a starting population. In our field assay, nesting tube diameter affected occupation rate and the sex ratio of O. brevicornis offspring. We describe a method for housing and controlled oral administration of sucrose solution in the laboratory, facilitating future studies on pesticide exposure. We conclude that O. brevicornis is a feasible model for assessing the risk of pesticides in the laboratory and in the field, especially for those compounds used in oilseed rape cultivation, as well as for investigating the general ecology of pollen specialists. By suggesting O. brevicornis as a potential model species, we aim to encourage diversification of the species used in agricultural ecology, especially to consider pollen specialists, and encourage attention to the foraging preferences and dietary needs of selected model species when considering pesticide exposure risk and effects.
Solving the Tension between High-Scale Inflation and Axion Isocurvature Perturbations
Creators: name: Higaki, Tetsutaro
name: Jeong, Kwang Sik
name: Takahashi, Fuminobu
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The BICEP2 experiment determined the Hubble parameter during inflation to be about $10^{14}$ GeV. Such high inflation scale is in tension with the QCD axion dark matter if the Peccei-Quinn (PQ) symmetry remains broken during and after inflation, because too large axion isocurvature perturbations would be generated. The axion isocurvature perturbations can be suppressed if the axion acquires a sufficiently heavy mass during inflation. We show that this is realized if the PQ symmetry is explicitly broken down to a discrete symmetry and if the breaking is enhanced during inflation. We also show that, even when the PQ symmetry becomes spontaneously broken after inflation, such a temporarily enhanced PQ symmetry breaking relaxes the constraint on the axion decay constant.
description: 21 pages, 2 figures. v3: references and a note added
A stable parametric finite element discretization of two-phase Navier–Stokes flow
Creators: name: Barrett, John W.
name: Garcke, Harald
name: Nürnberg, Robert
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: finite elements, XFEM, two-phase flow, Navier–Stokes, free boundary problem, surface tension, interface tracking
subject: 510 Mathematik
subject: 76T99
subject: 76M10
subject: 35Q30
subject: 65M12
subject: 65M60
subject: 76D05

description: We present a parametric finite element approximation of two-phase flow. This free boundary problem is given by the Navier–Stokes equations in the two phases, which are coupled via jump conditions across the interface. Using a novel variational formulation for the interface evolution gives rise to a natural discretization of the mean curvature of the interface. The parametric finite element approximation of the evolving interface is then coupled to a standard finite element approximation of the two-phase Navier–Stokes equations in the bulk. Here enriching the pressure approximation space with the help of an XFEM function ensures good volume conservation properties for the two phase regions. In addition, the mesh quality of the parametric approximation of the interface in general does not deteriorate over time, and an equidistribution property can be shown for a semidiscrete continuousin- time variant of our scheme in two space dimensions. Moreover, our finite element approximation can be shown to be unconditionally stable. We demonstrate the applicability of our method with some numerical results in two and three space dimensions.
Synthetic applications of aryl diazonium salts enabled by visible light photoredox catalysis
Creators: name: Hari, Durga Prasad
name: Hering, Thea
name: König, Burkhard
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: Visible light; aryl diazonium salts; photocatalysis; aryl radicals; Meerwein arylation
subject: 540 Chemie

description: The application of aryl radicals in organic synthesis is challenging, but very useful. Recently their generation from aryl diazonium salts via visible light photocatalysis has been developed as an efficient alternative to established methods in chemical synthesis. We summarize here our contributions to this fast developing area of research.
Efecto de la tiroxina como inductor a la metamorfosis del erizo de mar y el patrón de expresión del receptor nuclear COUP-TF en Lytechinns pictus /
Creators: name: Castellanos Kotkoff, Mónica Cecilia
Publisher: name: Universidad Autónoma de Baja California.
Year: 2022
Subjects: subject: Erizo de mar Cultivo||Biología Tésis
subject: SH399.S32 C38 2004

description: La Tiroxina es una hormona esteroide/tiroidea propia de vertebrados que actúa en el desarrollo y activa procesos como metamorfosis de anfibios.
Searching for gravitational waves from known pulsars at once and twice the spin frequency
Creators: name: Bejger, M.
name: Królak, A.
Publisher: name: arXiv
Year: 2013
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The existence of a superfluid core in the interior of a rotating neutron star may have an influence on its gravitational wave emission. In addition to the usually-assumed pure quadrupole radiation with the gravitational wave frequency at twice the spin frequency, a frequency of rotation itself may also be present in the gravitational wave spectrum. We study the parameters of a general model for such emission, compare it with previously proposed, simpler models, discuss the feasibility of the recovery of the stellar parameters and carry out the Monte Carlo simulations to test the performance of our estimation method.
description: 16 pages, 11 figures, CQG accepted
Interpolation in affine and projective space over a finite field
Creators: name: Hellus, Michael
name: Waldi, Rolf
Publisher: name: Universität Regensburg
Year: 2013
Subjects: subject: 510 Mathematik

description: Let s(n, q) be the smallest number s such that any n-fold Fq-valued interpolation problem in Pk Fq has a solution of degree s, that is: For any pairwise different Fq-rational points P1, . . . , Pn there exists a hypersurface H of degree s defined over Fq such that P1, . . . , Pn−1 ∈ H and Pn 6∈ H. This function s(n, q) was studied by Ernst Kunz and the second author in [KuW] and completely determined for q = 2 and q = 3. For q ≥ 4, we improve the results from [KuW]. The affine analogue to s(n, q) is the smallest number s = sa(n, q) such that any n-fold Fq-valued interpolation problem in Ak(Fq), k ∈ N>0 has a polynomial solution of degree ≤ s. We exactly determine this number.
Convergence of the stochastic weighted particle method for the Boltzmann equation
Creators: name: Matheis, Ingo
name: Wagner, Wolfgang
Publisher: name: Weierstrass Institute
Year: 2002
Subjects: subject: Boltzmann equation
subject: stochastic weighted particle method
subject: convergence
subject: variance reduction
subject: numerical experiment
subject: 65C05
subject: 76P05
subject: 82C80

description: This paper studies convergence of the stochastic weighted particle method for the Boltzmann equation. First the method is extended by introducing new stochastic reduction procedures, in order to control the number of simulation particles. Then, under rather general conditions, convergence to the solution of the Boltzmann equation is proved. Finally, numerical experiments are performed illustrating both convergence and considerable variance reduction, for the specific problem of calculating tails of the velocity distribution.
The Argo Simulation: I. Quenching of Massive Galaxies at High Redshift as a Result of Cosmological Starvation
Creators: name: Feldmann, Robert
name: Mayer, Lucio
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Observations show a prevalence of high redshift galaxies with large stellar masses and predominantly passive stellar populations. A variety of processes have been suggested that could reduce the star formation in such galaxies to observed levels, including quasar mode feedback, virial shock heating, or galactic winds driven by stellar feedback. However, the main quenching mechanisms have yet to be identified. Here we study the origin of star formation quenching using Argo, a cosmological, hydrodynamical zoom-in simulation that follows the evolution of a massive galaxy at $z\geq{}2$. This simulation adopts the same sub-grid recipes of the Eris simulations, which have been shown to form realistic disk galaxies, and, in one version, adopts also a mass and spatial resolution identical to Eris. The resulting galaxy has properties consistent with those of observed, massive (M_* ~ 1e11 M_sun) galaxies at z~2 and with abundance matching predictions. Our models do not include AGN feedback indicating that supermassive black holes likely play a subordinate role in determining masses and sizes of massive galaxies at high z. The specific star formation rate (sSFR) of the simulated galaxy matches the observed M_* - sSFR relation at early times. This period of smooth stellar mass growth comes to a sudden halt at z=3.5 when the sSFR drops by almost an order of magnitude within a few hundred Myr. The suppression is initiated by a leveling off and a subsequent reduction of the cool gas accretion rate onto the galaxy, and not by feedback processes. This "cosmological starvation" occurs as the parent dark matter halo switches from a fast collapsing mode to a slow accretion mode. Additional mechanisms, such as perhaps radio mode feedback from an AGN, are needed to quench any residual star formation of the galaxy and to maintain a low sSFR until the present time.
description: 20 pages, 12 figures, 2 tables, accepted for publication in MNRAS
Optimizing anode materials for lithium-ion batteries: The role of lithium iron phosphate/graphite composites
Creators: name: Devlet, Bayram
name: Keçebaş, Ali
name: Koç, Fatoş
name: Gizli, Nilay
name: Şahin, Utkucan
Publisher: name: Taylor & Francis
Year: 2024
Subjects: subject: Biochemistry
subject: Physiology
subject: FOS: Biological sciences
subject: Pharmacology
subject: Biotechnology
subject: Evolutionary Biology
subject: Chemical Sciences not elsewhere classified

description: In this study, a novel composite anode material for lithium-ion batteries has been developed, targeting advancements in energy storage technology. The study is centered on integrating various percentages of LiFePO4 known for its high thermal stability and high capacity when used as an anode active material with graphite to increase capacity and thermal durability of anode electrode. This approach has led to the creation of LiFePO4/graphite composite anodes, utilizing a slurry mixing technique to combine the beneficial properties of both materials. Thermogravimetric analysis indicate LiFePO4/graphite’s higher thermal stability than its graphite counterpart, which implies that the addition of LiFePO4 alters the thermal decomposition profile of the anode electrode. Electrochemical assessments show that particularly LiFePO4: graphite = 6:94 wt% composite anode electrode delivers the highest discharge capacity of 437 mAh g−1 with Coulombic efficiency of 95%; the highest discharge capacity of 385 mAh g−1 after 200 cycles at 70 mA g−1 with superior capacity retention and rate performance of 311.5 mAh g−1 at 700 mA g−1 compared to the graphite anode electrode. These findings highlight the potential of the LiFePO4/graphite composite as an anode material in improving lithium-ion battery performance, making it a viable option for future energy storage solutions.
Wiener filtering with a seismic underground array at the Sanford Underground Research Facility
Creators: name: Coughlin, Michael
name: Harms, Jan
name: Christensen, Nelson
name: Dergachev, Vladimir
name: DeSalvo, Riccardo
name: Kandhasamy, Shivaraj
name: Mandic, Vuk
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: A seismic array has been deployed at the Sanford Underground Research Facility in the former Homestake mine, South Dakota, to study the underground seismic environment. This includes exploring the advantages of constructing a third-generation gravitational-wave detector underground. A major noise source for these detectors would be Newtonian noise, which is induced by fluctuations in the local gravitational field. The hope is that a combination of a low-noise seismic environment and coherent noise subtraction using seismometers in the vicinity of the detector could suppress the Newtonian noise to below the projected noise floor for future gravitational-wave detectors. In this paper, we use Wiener filtering techniques to subtract coherent noise in a seismic array in the frequency band 0.05 -- 1\,Hz. This achieves more than an order of magnitude noise cancellation over a majority of this band. We show how this subtraction would benefit proposed future low-frequency gravitational wave detectors. The variation in the Wiener filter coefficients over the course of the day, including how local activities impact the filter, is analyzed. We also study the variation in coefficients over the course of a month, showing the stability of the filter with time. How varying the filter order affects the subtraction performance is also explored. It is shown that optimizing filter order can significantly improve subtraction of seismic noise, which gives hope for future gravitational-wave detectors to address Newtonian noise.