cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A Digital Twin Description Framework and its Mapping to Asset Administration Shell
Creators: name: Oakes, Bentley James
name: Parsai, Ali
name: Meyers, Bart
name: David, Istvan
name: Van Mierlo, Simon
name: Demeyer, Serge
name: Denil, Joachim
name: De Meulenaere, Paul
name: Vangheluwe, Hans
Publisher: name: arXiv
Year: 2022
Subjects: subject: Other Computer Science (cs.OH)
subject: FOS: Computer and information sciences

description: The pace of reporting on Digital Twin (DT) projects continues to accelerate both in industry and academia. However, these experience reports often leave out essential characteristics of the DT, such as the scope of the system-under-study, the insights and actions enabled, and the time-scale of processing. A lack of these details could therefore hamper both understanding of these DTs and development of DT tools and techniques. Our previous work developed a DT description framework with fourteen characteristics as a checklist for experience report authors to better describe the capabilities of their DT projects. This report provides an extended example of reporting to highlight the utility of this description framework, focusing on the DT of an industrial drilling machine. Furthermore, we provide a mapping from our description framework to the Asset Administration Shell (AAS) which is an emerging standard for Industry 4.0 system integration. This mapping aids practitioners in understanding how our description framework relates to AAS, potentially aiding in description or implementation activities.
Graph Universal Cycles: Compression and Connections to Universal Cycles
Creators: name: Kirsch, Rachel
name: Sibley, Clare
name: Sprangel, Elizabeth
Publisher: name: arXiv
Year: 2022
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05A05, 05C30, 05C45

description: Universal cycles, such as De Bruijn cycles, are cyclic sequences of symbols that represent every combinatorial object from some family exactly once as a consecutive subsequence. Graph universal cycles are a graph analogue of universal cycles introduced in 2010. We introduce graph universal partial cycles, a more compact representation of graph classes, which use "do not know" edges. We show how to construct graph universal partial cycles for labeled graphs, threshold graphs, and permutation graphs. For threshold graphs and permutation graphs, we demonstrate that the graph universal cycles and graph universal partial cycles are closely related to universal cycles and compressed universal cycles, respectively. Using the same connection, for permutation graphs, we define and prove the existence of an $s$-overlap form of graph universal cycles. We also prove the existence of a generalized form of graph universal cycles for unlabeled graphs.
description: 25 pages, 21 figures
Phase-dependent charge and heat current in thermally biased short Josephson junctions formed at helical edge states
Creators: name: Dutta, Paramita
Publisher: name: arXiv
Year: 2022
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We explore the phase-dependent charge and heat current in the short Josephson junctions with two normal metal regions attached at opposite ends, formed at helical edge states of two-dimensional topological insulators (TIs). For all finite phases, an asymmetry appears around the zero energy in the transmission spectra except for $ϕ\!=\!nϕ_0$, where $n$ is a half-integer and $ϕ_0$ ($=2π$) is the flux quantum. The phase-induced asymmetry plays a key role in inducing charge and heat current through the thermally biased junction. However, the current amplitudes are sensitive to the size of the junction. We show that in the short Josephson junction when subject to a temperature gradient, the charge current shows an odd-symmetry in phase. It indicates that the phase-tunable asymmetry around the zero-energy is not sufficient to induce a dissipative thermoelectric current in the junction. This is in contrast to the behavior of long Josephson junction as shown in the literature. The phase-tunable heat currents are obtained with amplitudes set by the phase difference, base temperature, and system size.
description: 12 pages, 6+3 figures; Revised version
Strong electron-phonon coupling and carrier self-trapping in Sb$_2$S$_3$
Creators: name: Liu, Yun
name: Wiktor, Julia
name: Monserrat, Bartomeu
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Antimony sulphide (Sb$_2$S$_3$) is an Earth-abundant and non-toxic material that is under investigation for solar energy conversion applications. However, it still suffers from poor power conversion efficiency and a large open circuit voltage loss that have usually been attributed to point or interfacial defects and trap states. More recently, a self-trapped exciton has been suggested as the microscopic origin for the performance loss. By using first-principles methods, we demonstrate that Sb$_2$S$_3$ exhibits strong electron-phonon coupling, which results in a large renormalization of 200 meV of the absorption edge when temperature increases from 10K to 300K, and in a quasi-1D electron polaron that is delocalized in the ribbon direction of the crystal structure, but localized in the inter-ribbon directions. The calculated polaron formation energy of 67 meV agrees well with experimental measurements, suggesting that self-trapped excitons are likely to form with the mediation of an electron polaron. Our results demonstrate the importance of systematically investigating electron-phonon coupling and polaron formation in the antimony chalcogenide family of semiconductors for optoelectronic applications.
description: 4 figures
Distance Domains: Completeness
Creators: name: Bice, Tristan
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Topology (math.GN)
subject: FOS: Mathematics
subject: 06A06, 18A35, 54E50, 54E55

description: We explore extensions of domain theoretic concepts, replacing transitive relations with general non-symmetric distances. These lead to a generalization of Smyth completeness which we characterize in various ways analogous to our previous Yoneda completeness characterizations.
description: This corresponds to the first half of the previous version, revised and now published. A revision of the second half will appear in a separate paper
A Systematic Review and Meta-Analysis of the Effectiveness of Brexanolone as a Treatment for Postpartum Depression
Creators: name: Beharry, Sarah
Publisher: name: Georgia State University
Year: 2024

description:
Postpartum depression (PPD) is a debilitating disorder that affects the functioning of new mothers and their ability to care for their infants. The onset of postpartum depression can be attributed to genetic and social factors as well as fluctuations in hormones during and after pregnancy. Brexanolone is a new medication developed to treat moderate to severe PPD. The present study aimed to complete a systematic review and meta-analysis of the available literature to support the claim that brexanolone is an effective medication to treat PPD. Additional aims include determining the demographic features of participants and the generalizability of the results. The Lancet, PubMed, PsycINFO, Embase, and Science Direct were searched using a Boolean search string to find primary studies and trials that were evaluating the efficacy of brexanolone with an outcome of changes in depression scores measured using the HAM-D among adults within 12 months postpartum. The collected studies were screened for eligibility and coded for study characteristics. The statistical analysis used a fixed effects model due to the small number of studies to estimate the mean effect size (standardized mean difference) using the metafor and tidyverse packages in R. The search yielded 233 articles, of which five were eligible. The statistical analyses yielded an SMD of 3.52 (95% CI: [3.16, 3.88]) for randomized controlled trials and an SMD accounting for pre-post of 2.97 (95% CI: [2.21, 3.73]) for single-group studies comparing outcome results to baseline data. There was significant heterogeneity among both the randomized controlled trial studies and the pre-post studies in their effect size estimates. This was indicated by the results of the Q-test for heterogeneity, which yielded results of Q = 12.8646 (p = 0.0049) and Q = 11.4964 (p = 0.0032) for the randomized controlled trials and pre-post studies, respectively. The Eggers regression test yielded a result of z = -8.4661 (p-value: <0.0001), indicating potential publication bias. The results were statistically significant, indicating that brexanolone is an effective treatment for women who suffer from moderate to severe PPD. Further studies investigating the efficacy of brexanolone should be conducted with larger and more diverse sample sizes.
Robust offset-free nonlinear model predictive control for systems learned by neural nonlinear autoregressive exogenous models
Creators: name: Xie, Jing
name: Bonassi, Fabio
name: Farina, Marcello
name: Scattolini, Riccardo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper presents a robust Model Predictive Control (MPC) scheme that provides offset-free setpoint tracking for systems described by Neural Nonlinear AutoRegressive eXogenous (NNARX) models. The NNARX model learns the dynamics of the plant from input-output data, and during the training the Incremental Input-to-State Stability ($δ$ISS) property is forced to guarantee stability. The trained NNARX model is then augmented with an explicit integral action on the output tracking error, which allows the control scheme to enjoy offset-free tracking ability. A tube-based MPC is finally designed, leveraging the unique structure of the model, to ensure robust stability and robust asymptotic zero error regulation for constant reference signals in the presence of model-plant mismatch or unknown disturbances. Numerical simulations on a water heating system show the effectiveness of the proposed control algorithm.
description: This is the peer reviewed version of http://doi.org/10.1002/rnc.6883, available in Open Access on the publisher's website. Please, cite Reference 16 instead
Income as a modifier of the relationship between cognitive impairment and education
Creators: name: Morgado, Lillian
Publisher: name: Georgia State University
Year: 2023

description:
INTRODUCTION: Education is considered a protective factor against cognitive decline. However, the relationship between education and cognition may be further complicated by additional factors. Income may moderate the protective association of education against cognitive decline.


AIM: Here we evaluate the 2020 Health and Retirement Study (HRS) wave to examine the strength of the relationship between education, income, and cognitive impairment.


METHODS: A cross-sectional analysis of the education, income, and cognition scores of 15,412 respondents to the 2020 HRS survey.


RESULTS: Results from this analysis show lower income levels reduce the protective association between education and cognition. Education has a protective association against cognitive impairment. Adjusting the odds ratio for income increases the odds ratio from 0.46 ( 95% CI, 0.438, 0.477, P< .001) to 0.56 (95% CI, 0.537, 0.589, P< .001) and reduces the protective association between cognitive impairment and education. Controlling for income has a greater effect than controlling for race, nursing home residency, gender, and total comorbidities combined.


DISCUSSION: Education is the single modifiable risk factor most protective against cognitive impairment in this analysis, but income has a strong modifying effect on this relationship. Interventions and policy initiatives that focus on increasing education levels to protect against cognitive impairment in old age would be strengthened by integrating income in their analysis.
Our Stories, Our Data: Co-designing Visualizations with People with Intellectual and Developmental Disabilities
Creators: name: Wu, Keke
name: Quadri, Ghulam Jilani
name: Wang, Arran Zeyu
name: Osei-Tutu, David Kwame
name: Petersen, Emma
name: Koushik, Varsha
name: Szafir, Danielle Albers
Publisher: name: arXiv
Year: 2024
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: Individuals with Intellectual and Developmental Disabilities (IDD) have unique needs and challenges when working with data. While visualization aims to make data more accessible to a broad audience, our understanding of how to design cognitively accessible visualizations remains limited. In this study, we engaged 20 participants with IDD as co-designers to explore how they approach and visualize data. Our preliminary investigation paired four participants as data pen-pals in a six-week online asynchronous participatory design workshop. In response to the observed conceptual, technological, and emotional struggles with data, we subsequently organized a two-day in-person co-design workshop with 16 participants to further understand relevant visualization authoring and sensemaking strategies. Reflecting on how participants engaged with and represented data, we propose two strategies for cognitively accessible data visualizations: transforming numbers into narratives and blending data design with everyday aesthetics. Our findings emphasize the importance of involving individuals with IDD in the design process, demonstrating their capacity for data analysis and expression, and underscoring the need for a narrative and tangible approach to accessible data visualization.
Production of Dirac Particles in External Electromagnetic Fields
Creators: name: Sogut, Kenan
name: Yanar, Hilmi
name: Havare, Ali
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Pair creation of spin- 1/2 particles in Minkowski spacetime is investigated by obtaining exact solu- tions of the Dirac equation in the presence of electromagnetic fields and using them for determining the Bogoliubov coefficients. The resulting particle creation number density depends on the strength of the electric and magnetic fields.
description: Accepted for publication in Acta Physica Polonica B
The electronic disorder landscape of mixed halide perovskites
Creators: name: Liu, Yun
name: Banon, Jean-Philippe
name: Frohna, Kyle
name: Chiang, Yu-Hsien
name: Tumen-Ulzii, Ganbaatar
name: Stranks, Samuel D.
name: Filoche, Marcel
name: Friend, Richard H.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Bandgap tunability of lead mixed-halide perovskites makes them promising candidates for various applications in optoelectronics since they exhibit sharp optical absorption onsets despite the presence of disorder from halide alloying. Here we use localization landscape theory to reveal that the static disorder due to compositional alloying for iodide:bromide perovskite contributes at most 3 meV to the Urbach energy. Our modelling reveals that the reason for this small contribution is due to the small effective masses in perovskites, resulting in a natural length scale of around 20nm for the "effective confining potential" for electrons and holes, with short range potential fluctuations smoothed out. The increase in Urbach energy across the compositional range agrees well with our optical absorption measurements. We model systems of sizes up to 80 nm in three dimensions, allowing us to explore halide segregation, accurately reproducing the experimentally observed absorption spectra and demonstrating the scope of our method to model electronic structures on large length scales. Our results suggest that we should look beyond static contribution and focus on the dynamic temperature dependent contribution to the Urbach energy.
description: 4 figures
On torsion in linearized Legendrian contact homology
Creators: name: Golovko, Roman
Publisher: name: arXiv
Year: 2022
Subjects: subject: Symplectic Geometry (math.SG)
subject: FOS: Mathematics

description: In this short note we discuss certain examples of Legendrian submanifolds, whose linearized Legendrian contact (co)homology groups over integers have non-vanishing algebraic torsion. More precisely, for a given arbitrary finitely generated abelian group $G$ and a positive integer $n\geq 3$, $n\neq 4$, we construct examples of Legendrian submanifolds of the standard contact vector space $\mathbb R^{2n+1}$, whose $n-1$-th linearized Legendrian contact (co)homology over $\mathbb Z$ computed with respect to a certain augmentation is isomorphic to $G$.
description: 5 pages, accepted version
A Quantitative Model of Triboelectric Charge Transfer
Creators: name: Olson, Karl P.
name: Marks, Laurence D.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Triboelectricity, when rubbing or contacting materials causes electric charge transfer, is ubiquitous across many fields, and has been studied in detail for centuries. Despite this, a complete description of triboelectricity remains elusive. Here, we analyze the contact between a metal asperity and a semiconductor, including contributions from the depletion zone of the semiconductor and from flexoelectric polarization that arises due to the strain gradients at asperity contacts. The free charges involved in charge transfer are then discussed and calculated. As a result, we develop a quantitative model for triboelectric charge transfer that details how charge transfer scales with contact parameters, the relative influence of depletion and flexoelectricity, and which agrees with various trends in multiple classes of triboelectric experiments.
Non-Hermitian skin effects on many-body localized and thermal phases
Creators: name: Wang, Yi-Cheng
name: Suthar, Kuldeep
name: Jen, H. H.
name: Hsu, Yi-Ting
name: You, Jhih-Shih
Publisher: name: arXiv
Year: 2022
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Localization in one-dimensional interacting systems can be caused by disorder potentials or non-Hermiticity. The former phenomenon is the many-body localization (MBL), and the latter is the many-body non-Hermitian skin effect (NHSE). In this work, we numerically investigate the interplay between these two kinds of localization, where the energy-resolved MBL arises from a deterministic quasiperiodic potential in a fermionic chain. We propose a set of eigenstate properties and long-time dynamics that can collectively distinguish the two localization mechanisms in the presence of non-Hermiticity. By computing the proposed diagnostics, we show that the thermal states are vulnerable to the many-body NHSE while the MBL states remain resilient up to a strong non-Hermiticity. Finally, we discuss experimental observables that can probe the difference between the two localizations in a non-Hermitian quasiperiodic fermionic chain. Our results pave the way toward experimental observations on the interplay of interaction, quasiperiodic potential, and non-Hermiticity.
description: 7 pages, 4 figures
Benchmarking with Supernovae: A Performance Study of the FLASH Code
Creators: name: Martin, Joshua
name: Feldman, Catherine
name: Siegmann, Eva
name: Curtis, Tony
name: Carlson, David
name: Coskun, Firat
name: Wood, Daniel
name: Gonzalez, Raul
name: Harrison, Robert J.
name: Calder, Alan C.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Astrophysical simulations are computation, memory, and thus energy intensive, thereby requiring new hardware advances for progress. Stony Brook University recently expanded its computing cluster "SeaWulf" with an addition of 94 new nodes featuring Intel Sapphire Rapids Xeon Max series CPUs. We present a performance and power efficiency study of this hardware performed with FLASH: a multi-scale, multi-physics, adaptive mesh-based software instrument. We extend this study to compare performance to that of Stony Brook's Ookami testbed which features ARM-based A64FX-700 processors, and SeaWulf's AMD EPYC Milan and Intel Skylake nodes. Our application is a stellar explosion known as a thermonuclear (Type Ia) supernova and for this 3D problem, FLASH includes operators for hydrodynamics, gravity, and nuclear burning, in addition to routines for the material equation of state. We perform a strong-scaling study with a 220 GB problem size to explore both single- and multi-node performance. Our study explores the performance of different MPI mappings and the distribution of processors across nodes. From these tests, we determined the optimal configuration to balance runtime and energy consumption for our application.
description: Accepted to PEARC '24 (Practice and Experience in Advanced Research Computing)
title: ИСТОРИЧЕСКАЯ СОЦИОЛОГИЯ ГОРОДА М. ВЕБЕРА И СОВРЕМЕННЫЕ УРБАНИСТИЧЕСКИЕ ИССЛЕДОВАНИЯ
Creators: name: Пирогов, Сергей
Publisher: name: Новгородский государственный университет имени Ярослава Мудрого (НовГУ)
Year: 2022

description: Статья посвящена анализу методологии познания города Макса Вебера и её значению для современных урбанистических исследований. Показано, что «понимающая социология» Вебера содержит идеи феноменологии, синергетики и когнитивного подхода, характерные для современных урбанистических исследований. Особенно важным тезисом для понимания урбанистических процессов является тезис Вебера о культуре как основе и ресурсе развития города. В статье показано, что идеи «понимающей социологии» Вебера когерентны таким концептам современной гуманитарной науки, как «практики», «габитус», «когнитивная модель». Тезисы Вебера о полифакторности возникновения и существования собственных механизмов саморазвития города и сегодня могут быть аргументами при принятии решений о развития города. Работа М. Вебера «Город» является методологически важной для обсуждения общегуманитарной методологической проблемы соотношения структуры и действия: (а) система определяет действия индивидов или (б) их повседневные действия постепенно и постоянно меняют систему?
Field extension of real values of physical observables in classical theory can help attain quantum results
Creators: name: Wang, Hai
name: Kumar, Asutosh
name: Wu, Junde
name: Cho, Minhyung
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Physical quantities are assumed to take real values, which stems from the fact that an usual measuring instrument that measures a physical observable always yields a real number. Here we consider the question of what will happen if physical observables are allowed to take complex values. In this paper, we show that by allowing observables in the Bell inequality to take complex values, a classical physical theory can actually get the same upper bound of the Bell expression as quantum theory. Also, by extending the real field to the quaternionic field, we can puzzle out the GHZ problem using local hidden variable model. Furthermore, we try to build a new type of hidden-variable theory of a single qubit based on the result.
Extreme AGN Variability in LSST and Synergies with ESO facilities
Creators: name: Temple, Matthew
Publisher: name: Zenodo
Year: 2024

description: I present an overview of AGN varibility science in LSST, with a particular focus on extreme AGN variability and potential synergies with ESO follow-up facilities. Our understanding of AGN variability is continually increasing with data from ongoing surveys, but the Rubin Observatory will open a new discovery window in parameter space. LSST will be able to identify extreme variability events in AGN, which could be driven by rapid changes in the SMBH accretion flow, changes in obscuration, jet activity, microlensing, or possibly even more exotic physics. This multiplicity of physical mechanisms means that  changes in the LSST photometric time series will not always correlate with changes in the spectroscopic type classification. Timely spectroscopic and/or multiwavelength follow-up will be required to classify such phenomena, and subsequent monitoring will be crucially important to provide the observational foundation for physical interpretation. However, such objects will first need to be selected from the LSST data stream - all AGN are variable at some level and care will be needed to identify “extreme” variability events from the background defined by the rest of the AGN population.
Interrelated Thermalization and Quantum Criticality in a Lattice Gauge Simulator
Creators: name: Wang, Han-Yi
name: Zhang, Wei-Yong
name: Yao, Zhi-Yuan
name: Liu, Ying
name: Zhu, Zi-Hang
name: Zheng, Yong-Guang
name: Wang, Xuan-Kai
name: Zhai, Hui
name: Yuan, Zhen-Sheng
name: Pan, Jian-Wei
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Gauge theory and thermalization are both foundations of physics and nowadays are both topics of essential importance for modern quantum science and technology. Simulating lattice gauge theories (LGTs) realized recently with ultracold atoms provides a unique opportunity for carrying out a correlated study of gauge theory and thermalization in the same setting. Theoretical studies have shown that an Ising quantum phase transition exists in this implemented LGT, and quantum thermalization can also signal this phase transition. Nevertheless, it remains an experimental challenge to accurately determine the critical point and controllably explore the thermalization dynamics in the quantum critical regime due to the lack of techniques for locally manipulating and detecting matter and gauge fields. Here, we report an experimental investigation of the quantum criticality in the LGT from both equilibrium and non-equilibrium thermalization perspectives by equipping the single-site addressing and atom-number-resolved detection into our LGT simulator. We accurately determine the quantum critical point agreed with the predicted value. We prepare a $|Z_{2}\rangle$ state deterministically and study its thermalization dynamics across the critical point, leading to the observation that this $|Z_{2}\rangle$ state thermalizes only in the critical regime. This result manifests the interplay between quantum many-body scars, quantum criticality, and symmetry breaking.
description: 6+4 pages, 4+7 figures
title: Book of abstracts
title: Big Stuff 2022
titleType: Subtitle
Creators: name: Filipe, Graça
name: Tissot, Isabel
name: Manso, Marta
Publisher: name: Universidade Nova de Lisboa - Faculdade de Ciências e Tecnologia
Year: 2022

description: The Big Stuff conference is now almost twenty years old. It began as a workshop attached to Metal 04, the International Conference on Conservation of Metals held in Canberra, Australia. It filled a gap in the heritage and conservation world that nothing else was addressing – the peculiar challenges of large, mostly metal assemblages of parts that we call machines. Often perceived as purely utilitarian, they are in fact entwined with vibrant intangible heritage cultures of work, life and practice, which depend upon continued operation of the machinery for their survival and transmission to future generations. The size of big machines; the role that changeability and movement plays in their essence, interpretation and conservation; their role in both industrial and domestic spheres of life; and the way that at the largest scales machines and buildings become indistinguishable parts of a whole – all these aspects act to disrupt traditional disciplinary boundaries such as materials conservation, built heritage conservation, industrial heritage and military heritage. A passionate international community of scholars, practitioners, volunteers, and machinery owners has shaped Big Stuff over the ensuing five conferences, held in Germany, the United Kingdom, Canada, France and Poland. The opportunity to meet regularly with friends and colleagues, and to share ideas across disciplines to expand our knowledge and practice has been a constant pleasure and a driver of new ideas and collaborations. One challenge has always been to make the conference accessible to people who are unable to travel internationally to be with us, so the addition this year of the option for online participation is an exciting development. The program offered in 2022 in Seixal, Portugal is filled with innovative presentations and complemented with tours of some of Portugal’s most interesting large technology sites, taking Big Stuff in exciting new directions.
description: Book of abstracts: Big Stuff 2022 : WORKING TOGETHER Conservation and safeguarding of industrial and technological heritage. / Manso, Marta (Editor/Coordinator); Filipe, Maria da Graça (Editor/Coordinator); Tissot, Isabel (Editor/Coordinator). Lisboa : Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2022. 47 p. ISBN: 978-972-99923-8-4
The Ramsey theory of the universal homogeneous triangle-free graph
Creators: name: Dobrinen, Natasha
Publisher: name: arXiv
Year: 2017
Subjects: subject: Logic (math.LO)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: The universal homogeneous triangle-free graph, constructed by Henson and denoted $\mathcal{H}_3$, is the triangle-free analogue of the Rado graph. While the Ramsey theory of the Rado graph has been completely established, beginning with Erdős-Hajnal-Posá and culminating in work of Sauer and Laflamme-Sauer-Vuksanovic, the Ramsey theory of $\mathcal{H}_3$ had only progressed to bounds for vertex colorings (Komjáth-Rödl) and edge colorings (Sauer). This was due to a lack of broadscale techniques. We solve this problem in general: For each finite triangle-free graph $G$, there is a finite number $T(G)$ such that for any coloring of all copies of $G$ in $\mathcal{H}_3$ into finitely many colors, there is a subgraph of $\mathcal{H}_3$ which is again universal homogeneous triangle-free in which the coloring takes no more than $T(G)$ colors. This is the first such result for a homogeneous structure omitting copies of some non-trivial finite structure. The proof entails developments of new broadscale techniques, including a flexible method for constructing trees which code $\mathcal{H}_3$ and the development of their Ramsey theory.
description: Accepted to Journal of Mathematical Logic. 65 pages. A few references updated
Micro and macro facial expressions by driven animations in realistic Virtual Humans
Creators: name: Montanha, Rubens Halbig
name: Raupp, Giovana Nascimento
name: Schmitt, Ana Carolina Policarpo
name: Araujo, Victor Flávio de Andrade
name: Musse, Soraia Raupp
Publisher: name: arXiv
Year: 2024
Subjects: subject: Graphics (cs.GR)
subject: FOS: Computer and information sciences

description: Computer Graphics (CG) advancements have allowed the creation of more realistic Virtual Humans (VH) through modern techniques for animating the VH body and face, thereby affecting perception. From traditional methods, including blend shapes, to driven animations using facial and body tracking, these advancements can potentially enhance the perception of comfort and realism in relation to VHs. Previously, Psychology studied facial movements in humans, with some works separating expressions into macro and micro expressions. Also, some previous CG studies have analyzed how macro and micro expressions are perceived, replicating psychology studies in VHs, encompassing studies with realistic and cartoon VHs, and exploring different VH technologies. However, instead of using facial tracking animation methods, these previous studies animated the VHs using blendshapes interpolation. To understand how the facial tracking technique alters the perception of VHs, this paper extends the study to macro and micro expressions, employing two datasets to transfer real facial expressions to VHs and analyze how their expressions are perceived. Our findings suggest that transferring facial expressions from real actors to VHs significantly diminishes the accuracy of emotion perception compared to VH facial animations created by artists.
Transport coefficients of two-flavor quark matter from the Kubo formalism
Creators: name: Harutyunyan, Arus
name: Rischke, Dirk H.
name: Sedrakian, Armen
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The transport coefficients of quark matter at non-zero chemical potential and temperature are computed within the two-flavor Nambu--Jona-Lasinio model. We apply the Kubo formalism to obtain the thermal ($κ$) and electrical ($σ$) conductivities as well as an update of the shear viscosity ($η$) by evaluating the corresponding equilibrium two-point correlation functions to leading order in the $1/N_c$ expansion. The Dirac structure of the self-energies and spectral functions is taken into account as these are evaluated from the meson-exchange Fock diagrams for on-mass-shell quarks. We find that the thermal and electrical conductivities are decreasing functions of temperature and density above the Mott temperature $T_{\rm M}$ of dissolution of mesons into quarks, the main contributions being generated by the temporal and vector components of the spectral functions. The coefficients show a universal dependence on the ratio $T/T_{\rm M}$ for different densities, i.e., the results differ by a chemical-potential dependent constant. We also show that the Wiedemann-Franz law for the ratio $σ/κ$ does not hold. The ratio $η/s $, where $s$ is the entropy density, is of order of unity (or larger) close to the Mott temperature and, as the temperature increases, approaches the AdS/CFT bound $1/4π$. It is also conjectured that the ratio $κT/c_V $, with $c_V$ being the specific heat, is bounded from below by $1/18$.
description: 24 pages, 19 figures, RevTeX format; v2: minor corrections, matches published version; v3: corrected a minor typo in Eq. (53) and a following sentence
Image Triangulation Using the Sobel Operator for Vertex Selection
Creators: name: Laske, Olivia
name: Ziegelmeier, Lori
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computational Geometry (cs.CG)
subject: FOS: Computer and information sciences
subject: I.3.5
subject: 65D18

description: Image triangulation, the practice of decomposing images into triangles, deliberately employs simplification to create an abstracted representation. While triangulating an image is a relatively simple process, difficulties arise when determining which vertices produce recognizable and visually pleasing output images. With the goal of producing art, we discuss an image triangulation algorithm in Python that utilizes Sobel edge detection and point cloud sparsification to determine final vertices for a triangulation, resulting in the creation of artistic triangulated compositions.
description: Appeared in the 40th International Symposium on Computational Geometry (Media Exposition)
Bayesian Approaches to Designing Replication Studies
Creators: name: Pawel, Samuel
name: Consonni, Guido
name: Held, Leonhard
Publisher: name: arXiv
Year: 2022
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Replication studies are essential for assessing the credibility of claims from original studies. A critical aspect of designing replication studies is determining their sample size; a too small sample size may lead to inconclusive studies whereas a too large sample size may waste resources that could be allocated better in other studies. Here, we show how Bayesian approaches can be used for tackling this problem. The Bayesian framework allows researchers to combine the original data and external knowledge in a design prior distribution for the underlying parameters. Based on a design prior, predictions about the replication data can be made, and the replication sample size can be chosen to ensure a sufficiently high probability of replication success. Replication success may be defined by Bayesian or non-Bayesian criteria, and different criteria may also be combined to meet distinct stakeholders and enable conclusive inferences based on multiple analysis approaches. We investigate sample size determination in the normal-normal hierarchical model where analytical results are available and traditional sample size determination is a special case where the uncertainty on parameter values is not accounted for. We use data from a multisite replication project of social-behavioral experiments to illustrate how Bayesian approaches can help design informative and cost-effective replication studies. Our methods can be used through the R package BayesRepDesign.
Heatmap-based Out-of-Distribution Detection
Creators: name: Hornauer, Julia
name: Belagiannis, Vasileios
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Our work investigates out-of-distribution (OOD) detection as a neural network output explanation problem. We learn a heatmap representation for detecting OOD images while visualizing in- and out-of-distribution image regions at the same time. Given a trained and fixed classifier, we train a decoder neural network to produce heatmaps with zero response for in-distribution samples and high response heatmaps for OOD samples, based on the classifier features and the class prediction. Our main innovation lies in the heatmap definition for an OOD sample, as the normalized difference from the closest in-distribution sample. The heatmap serves as a margin to distinguish between in- and out-of-distribution samples. Our approach generates the heatmaps not only for OOD detection, but also to indicate in- and out-of-distribution regions of the input image. In our evaluations, our approach mostly outperforms the prior work on fixed classifiers, trained on CIFAR-10, CIFAR-100 and Tiny ImageNet. The code is publicly available at: https://github.com/jhornauer/heatmap_ood.
description: Accepted to WACV 2023
Excitation Variance Matching with Limited Configuration Interaction Expansions in Variational Monte Carlo
Creators: name: Robinson, Paul J.
name: Flores, Sergio D. Pineda
name: Neuscamman, Eric
Publisher: name: arXiv
Year: 2017
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: In the regime where traditional approaches to electronic structure cannot afford to achieve accurate energy differences via exhaustive wave function flexibility, rigorous approaches to balancing different states' accuracies become desirable. As a direct measure of a wave function's accuracy, the energy variance offers one route to achieving such a balance. Here, we develop and test a variance matching approach for predicting excitation energies within the context of variational Monte Carlo and selective configuration interaction. In a series of tests on small but difficult molecules, we demonstrate that the approach it is effective at delivering accurate excitation energies when the wave function is far from the exhaustive flexibility limit. Results in C$_3$, where we combine this approach with variational Monte Carlo orbital optimization, are especially encouraging.
description: 11 pages, 7 figures, 2 tables
Nested invariant tori foliating a vector field and its curl: toward MHD equilibria and steady Euler flows in toroidal domains without continuous Euclidean isometries
Creators: name: Sato, Naoki
name: Yamada, Michio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: This paper studies the problem of finding a three-dimensional solenoidal vector field such that both the vector field and its curl are tangential to a given family of toroidal surfaces. We show that this question can be translated into the problem of determining a periodic solution with periodic derivatives of a two-dimensional linear elliptic second-order partial differential equation on each toroidal surface, and prove the existence of smooth solutions. Examples of smooth solutions foliated by toroidal surfaces that are not invariant under continuous Euclidean isometries are also constructed explicitly, and they are identified as equilibria of anisotropic magnetohydrodynamics. The problem examined here represents a weaker version of a fundamental mathematical problem that arises in the context of magnetohydrodynamics and fluid mechanics concerning the existence of regular equilibrium magnetic fields and steady Euler flows in bounded domains without continuous Euclidean isometries. The existence of such configurations represents a key theoretical issue for the design of the confining magnetic field in nuclear fusion reactors known as stellarators.
description: 22 pages, 4 figures
Halo nonlinear reconstruction
Creators: name: Yu, Yu
name: Zhu, Hong-Ming
name: Pen, Ue-Li
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We apply the nonlinear reconstruction method to simulated halo fields. For halo number density $2.77\times 10^{-2}$ $(h^{-1} {\rm Mpc})^{-3}$ at $z=0$, corresponding to the SDSS main sample density, we find the scale where the noise saturates the linear signal is improved to $k\gtrsim0.36\ h {\rm Mpc}^{-1}$, a factor of $2.29$ improvement in scale, or $12$ in number of linear modes. The improvement is less for higher redshift or lower halo density. We expect this to substantially improve the BAO accuracy of dense, low redshift surveys, including the SDSS main sample, 6dFGS and 21cm intensity mapping initiatives.
description: 10 pages, 7 figures, published on ApJ. Match to published version. Two subsections and two figures are added
Charmonium production in $p$Ne collisions at $\sqrt{s_{\rm NN}}=68.5$ GeV
Creators: name: LHCb Collaboration
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The measurement of charmonium states produced in proton-neon ($p$Ne) collisions by the LHCb experiment in its fixed-target configuration is presented. The production of $J/ψ$ and $ψ(2S)$ mesons is studied with a beam of 2.5 TeV protons colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy $\sqrt{s_{\rm NN}}=68.5$ GeV. The data sample corresponds to an integrated luminosity of $21.7\pm 1.4 $ nb$^{-1}$. The $J/ψ$ and $ψ(2S)$ hadrons are reconstructed in $μ^+μ^-$ final states. The $J/ψ$ production cross-section per target nucleon in the centre-of-mass rapidity range $y^{*}\in [-2.29, 0]$ is found to be $506 \pm 8 \pm 25 \textrm{ nb/nucleon}$. The $ψ(2S)$ to $J/ψ$ relative production rate is found to be $(1.67 \pm 0.27\pm 0.10)\%$ in good agreement with other measurements involving beam and target nuclei of similar sizes.
description: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-014.html (LHCb public pages)
ChartEye: A Deep Learning Framework for Chart Information Extraction
Creators: name: Mustafa, Osama
name: Ali, Muhammad Khizer
name: Moetesum, Momina
name: Siddiqi, Imran
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: The widespread use of charts and infographics as a means of data visualization in various domains has inspired recent research in automated chart understanding. However, information extraction from chart images is a complex multitasked process due to style variations and, as a consequence, it is challenging to design an end-to-end system. In this study, we propose a deep learning-based framework that provides a solution for key steps in the chart information extraction pipeline. The proposed framework utilizes hierarchal vision transformers for the tasks of chart-type and text-role classification, while YOLOv7 for text detection. The detected text is then enhanced using Super Resolution Generative Adversarial Networks to improve the recognition output of the OCR. Experimental results on a benchmark dataset show that our proposed framework achieves excellent performance at every stage with F1-scores of 0.97 for chart-type classification, 0.91 for text-role classification, and a mean Average Precision of 0.95 for text detection.
description: 8 Pages, and 11 Figures
An Integrated Optimization + Learning Approach to Optimal Dynamic Pricing for the Retailer with Multi-type Customers in Smart Grids
Creators: name: Meng, Fanlin
name: Zeng, Xiao-Jun
name: Zhang, Yan
name: Dent, Chris J.
name: Gong, Dunwei
Publisher: name: arXiv
Year: 2016
Subjects: subject: Systems and Control (eess.SY)
subject: Artificial Intelligence (cs.AI)
subject: Computer Science and Game Theory (cs.GT)
subject: Optimization and Control (math.OC)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: In this paper, we consider a realistic and meaningful scenario in the context of smart grids where an electricity retailer serves three different types of customers, i.e., customers with an optimal home energy management system embedded in their smart meters (C-HEMS), customers with only smart meters (C-SM), and customers without smart meters (C-NONE). The main objective of this paper is to support the retailer to make optimal day-ahead dynamic pricing decisions in such a mixed customer pool. To this end, we propose a two-level decision-making framework where the retailer acting as upper-level agent firstly announces its electricity prices of next 24 hours and customers acting as lower-level agents subsequently schedule their energy usages accordingly. For the lower level problem, we model the price responsiveness of different customers according to their unique characteristics. For the upper level problem, we optimize the dynamic prices for the retailer to maximize its profit subject to realistic market constraints. The above two-level model is tackled by genetic algorithms (GA) based distributed optimization methods while its feasibility and effectiveness are confirmed via simulation results.
description: 38 pages, 6 figures
$J/ψ$ and $D^0$ production in $\sqrt{s_{\rm NN}}$ = 68.5 GeV PbNe collisions
Creators: name: LHCb Collaboration
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The first measurement of $J/ψ$ and $D^0$ production in PbNe collisions by the LHCb experiment in its fixed-target configuration is reported. The production of $J/ψ$ and $D^0$ mesons is studied with a beam of lead ions with an energy of 2.5 TeV per nucleon colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy of $\sqrt{s_{\rm NN}}$ = 68.5 GeV. The $J/ψ/D^0$ production cross-section ratio is studied as a function of rapidity, transverse momentum and collision centrality. These data are compared with measurements from $p$Ne collisions at the same energy and show no difference in the observed $J/ψ$ suppresion trend when comparing $p$Ne and PbNe peripheral collisions with PbNe central collisions.
description: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-011.html (LHCb public pages). arXiv admin note: text overlap with arXiv:1810.07907