cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Global interactions, information flow, and chaos synchronization
Creators: name: Paredes, G.
name: Alvarez-Llamoza, O.
name: Cosenza, M. G.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: We investigate the relationship between the emergence of chaos synchronization and the information flow in dynamical systems possessing homogeneous or heterogeneous global interactions whose origin can be external (driven systems) or internal (autonomous systems). By employing general models of coupled chaotic maps for such systems, we show that the presence of a homogeneous global field, either external or internal, for all times is not indispensable for achieving complete or generalized synchronization in a system of chaotic elements. Complete synchronization can also appear with heterogeneous global fields; it does not requires the simultaneous sharing of the field by all the elements in a system. We use the normalized mutual information and the information transfer between global and local variables to characterize complete and generalized synchronization. We show that these information measures can characterize both types of synchronized states and also allow to discern the origin of a global interaction field. A synchronization state emerges when a sufficient amount of information provided by a field is shared by all the elements in the system, on the average over long times. Thus, the maximum value of the top-down information transfer can be used as a predictor of synchronization in a system, as a parameter is varied.
description: 9 pages, 5 figures
A Novel Distance Measure for Heterogeneous Data: Time Series and Non-Temporal Data
Creators: name: Moura, Mirlei ; Barreto, Marcos
Publisher: name: Zenodo
Year: 2022
Subjects: clustering, classification, mixed data, heterogeneous data, time series, distance measure

description: Amongst the several machine learning techniques, distance (or similarity) measures are used to calculate the proximity of objects in a dataset. By employing such a type of measure, it is possible to generate “clusters” in unsupervised learning techniques or classify the objects in supervised learning techniques. In general, these measures are projected considering only one type of data. Datasets from real-world applications can comprise a mixture of data, thus requiring different approaches for identifying such patterns and groups. Literature is centred around three main approaches for leading with heterogeneous data: i) using a unique distance measure to all data types, ii) using specific measures for each data type, or iii) converting all data types to a unique type and then applying the first approach. Conversely, applying machine learning techniques in a dataset with time series and non-temporal data is not trivial because temporal data can have different behaviours that influence distance measures. Therefore, this work proposes a measure that enables the calculation of the distance between objects comprised of times series and numerical data features. To develop this measure, we first sought to identify and analyse existing works with mixed data clustering approaches involving temporal data. Then, we combine measures, for a unique data type, to deal with heterogeneous datasets to generate a unique measure for time series and non-temporal data.
ELVIS: Exploring the Local Volume in Simulations
Creators: name: Garrison-Kimmel, Shea
name: Boylan-Kolchin, Michael
name: Bullock, James
name: Lee, Kyle
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We introduce a set of high-resolution dissipationless simulations that model the Local Group (LG) in a cosmological context: Exploring the Local Volume in Simulations (ELVIS). The suite contains 48 Galaxy-size halos, each within high-resolution volumes that span 2-5 Mpc in size, and each resolving thousands of systems with masses below the atomic cooling limit. Half of the ELVIS galaxy halos are in paired configurations similar to the Milky Way (MW) and M31; the other half are isolated, mass-matched analogs. We find no difference in the abundance or kinematics of substructure within the virial radii of isolated versus paired hosts. On Mpc scales, however, LG-like pairs average almost twice as many companions and the velocity field is kinematically hotter and more complex. We present a refined abundance matching relation between stellar mass and halo mass that reproduces the observed satellite stellar mass functions of the MW and M31 down to the regime where incompleteness is an issue, $M_\star \sim 5\times 10^5 \, M_\odot$. Within a larger region spanning approximately 3 Mpc, the same relation predicts that there should be $\sim$ 1000 galaxies with $M_\star > 10^{3}\,M_\odot$ awaiting discovery. We show that up to 50% of halos within 1 Mpc of the MW or M31 could be systems that have previously been within the virial radius of either giant. By associating never-accreted halos with gas-rich dwarfs, we show that there are plausibly 50 undiscovered dwarf galaxies with HI masses $> 10^5\,M_\odot$ within the Local Volume. The radial velocity distribution of these predicted gas-rich dwarfs can be used to inform follow-up searches based on ultra-compact high-velocity clouds found in the ALFALFA survey.
description: 22 pages, 19 figures, 3 tables; v2 -- accepted to MNRAS. Movies, images, and data are available at http://localgroup.ps.uci.edu/elvis
An Approach to Support the Personalization of Self-expressive Avatars in the Metaverse
Creators: name: Ribeiro, Ailton
name: Vieira, Vaninha
Publisher: name: Zenodo
Year: 2022

description: The avatar is a digital character that represents a person in a virtual environment, such as the metaverse. It is widely used in games and is also becoming a reality in other domains. Research indicates that the characteristics of a person’s avatar can influence his/her behavior while using a system, improving the sense of presence, immersion, and self-expression. A found gap is how to support developers proposing avatar personalization, considering a user’s context, and understanding how context awareness applied to avatars influences self-expression. Researchers have also discussed the possible aspects (positive and negative) that the digital platforms that support the metaverse can have for people in the context of teaching-learning. We discuss how human, cultural and contextual factors influence the personalization of avatars and some insights to understand the psychology of avatar personalization and its potential usefulness in communication practices in immersive virtual environments.
Exceptional conformal anomaly of null polygonal Wilson loops
Creators: name: Dorn, Harald
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We analyse the breaking of conformal invariance for null polygonal Wilson loops in ${\cal N}=4$ SYM beyond that induced by the UV divergences due to the cusps. It only shows up in exceptional configurations, where the polygon intersects the critical light cone of an inversion or a special conformal transformation. In comparison with the related study for the Euclidean version by Drukker and Gross, we find different leading terms both for weak as well as for strong coupling. Hence the conformal anomaly due to intersections of a null polygon with a critical light cone defines a new universal function of the coupling constant.
description: 17 pages, 7 figures, sign error in (20) corrected, comment on smooth space-like contours added, version to appear in JHEP
title: Communication, Romantic Reconciliation, and Emerging Adulthood: A Relational Dialectics Study
Creators: name: Poole, Ashley M.
Publisher: name: Old Dominion University Libraries
Year: 2014

description: Building on the extant research of on-again/off-again (on-off) romantic relationships, the current thesis focused on building upon past findings by utilizing a unique theoretical methodology in an emerging demographic. A sample of 22 emergent adult (ages 18-29) participants who were currently in or had recently experienced an on-off relationship completed face-to-face interviews discussing communicative processes during romantic reconciliation. The primary purpose of this thesis was to identify and define discursive struggles found within on-off relationships during reconciliation attempts, and understand how they are used between partners to give meaning to the terms "on" and "off" as a precursor to restructuring relational identity after reconciliation. More specifically, the goals of this study were to better understand how on-off partners create meaning through their discourses, rather than focus on previously identified on-off characteristics. As a result, this thesis focused on the unique romantic partnerships at a dialogic level.

Contrapuntal analysis (Baxter, 2011) was performed to answer five proposed research questions. Findings indicated that relational production, in comparison to relational reproduction was a defining discursive struggle during reconciliation. The data suggested partners using relational reproduction were less likely to have a successful reconciliation as they continued to harbor past relational tensions in the present relationship. Further, the production-reproduction discourse was found to produce a nuanced understanding of relational maintenance. Specifically, on-off relationships viewed from a dialogic perspective favor relational maintenance as a form of change versus relational maintenance as continuity of the past status quo. The presence and impact of social network support, relational uncertainty, and ambiguity surrounding on-off terminology within and between partners were also discussed. Finally, potential avenues for future research examining on-off relationships across the life course were discussed.
On reconstruction of dynamic permeability and tortuosity from data at distinct frequencies
Creators: name: Ou, Miao-Jung Yvonne
Publisher: name: arXiv
Year: 2013
Subjects: subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 28, 41, 74, 86, 92

description: This article focuses on the mathematical problem of reconstructing dynamic permeability $K(ω)$ of two-phase composites from data at different frequencies, utilizing the analytic structure of the Stieltjes function representation of $K(ω)$ derived by Avellaneda and Tortquato in \cite{avellaneda1991rigorous-link-b}, which is valid for all pore space geometry. The integral representation formula (IRF) for dynamic tortuosity is derived and its analytic structure exploited for reconstructing the function from a finite data set. All information of pore-space microstructure is contained in the measure of the IRF. The theory of multipoint Padé approximates for Stieltjes functions guarantees the existence of relaxation kernels that can approximate the dynamic permeability function and the dynamic tortuosity function with high accuracy. In this paper, a numerical algorithm is proposed for computing the relaxation time and the corresponding strength for each element in the relaxation kernels; in the frequency domain, the approximation can be regarded as approximating the Stieltjes function by rational functions with simple poles and positive residues. With the idea from dehomogenization, we also established the exact relations between the moments of the positive measures in the IRFs of permeability and tortuosity with two important parameters in the theory of poroelasticity: the infinite-frequency tortuosity $α_\infty$ for general case and the weighted volume-to-surface ratio $Λ$ for the JKD model. From these relations, we suggest a new way for evaluating these two microstructure-dependent parameters from a finite data set of permeability and given values of porosity $ϕ$ and pore fluid kinetic viscosity $ν$. Numerical results for JKD permeability and tortuosity are presented.
description: 20 pages, 3 figures
Holographic Entanglement Entropy for General Higher Derivative Gravity
Creators: name: Dong, Xi
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We propose a general formula for calculating the entanglement entropy in theories dual to higher derivative gravity where the Lagrangian is a contraction of Riemann tensors. Our formula consists of Wald's formula for the black hole entropy, as well as corrections involving the extrinsic curvature. We derive these corrections by noting that they arise from naively higher order contributions to the action which are enhanced due to would-be logarithmic divergences. Our formula reproduces the Jacobson-Myers entropy in the context of Lovelock gravity, and agrees with existing results for general four-derivative gravity. We emphasize that the formula should be evaluated on a particular bulk surface whose location can in principle be determined by solving the equations of motion with conical boundary conditions. This may be difficult in practice, and an alternative method is desirable. A natural prescription is simply minimizing our formula, analogous to the Ryu-Takayanagi prescription for Einstein gravity. We show that this is correct in several examples including Lovelock and general four-derivative gravity.
description: 1+35 pages, 2 figures; v2: typos fixed, references added, and other improvements; v3: corrected a previous omission in counting, other clarifications; v4: minor clarifications, references added, published version
Real-time dynamics of string breaking
Creators: name: Hebenstreit, Florian
name: Berges, Jürgen
name: Gelfand, Daniil
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the real-time dynamics of string breaking in quantum electrodynamics in one spatial dimension. A two-stage process with a clear separation of time and energy scales for the fermion--antifermion pair creation and subsequent charge separation leading to the screening of external charges is found. Going away from the traditional setup of external static charges, we establish the phenomenon of multiple string breaking by considering dynamical charges flying apart.
description: 5 pages, 4 figures. Revised version: Discussion extended and one figure added, PRL Version
Direct observation of dynamic charge stripes in La2-xSrxNiO4
Creators: name: Anissimova, S.
name: Parshall, D.
name: Gu, G. D.
name: Marty, K.
name: Lumsden, M. D.
name: Chi, Songxue
name: Fernandez-Baca, J. A.
name: Abernathy, D. L.
name: Lamago, D.
name: Tranquada, J. M.
name: Reznik, D.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The insulator-to-metal transition continues to be a challenging subject, especially when electronic correlations are strong. In layered compounds, such as La2-xSrxNiO4 and La2-xBaxCuO4, the doped charge carriers can segregate into periodically-spaced charge stripes separating narrow domains of antiferromagnetic order. Although there have been theoretical proposals of dynamically fluctuating stripes, direct spectroscopic evidence of charge-stripe fluctuations has been lacking. Here we report the detection of critical lattice fluctuations, driven by charge-stripe correlations, in La2-xSrxNiO4 using inelastic neutron scattering. This scattering is detected at large momentum transfers where the magnetic form factor suppresses the spin fluctuation signal. The lattice fluctuations associated with the dynamic charge stripes are narrow in q and broad in energy. They are strongest near the charge stripe melting temperature. Our results open the way towards the quantitative theory of dynamic stripes and for directly detecting dynamical charge stripes in other strongly-correlated systems, including high-temperature superconductors such as La2-xSrxCuO4.
description: Nature Communications, in press, 9 pages 10 figures, completely new version
Analysis of block-preconditioners for models of coupled magma/mantle dynamics
Creators: name: Rhebergen, Sander
name: Wells, Garth N.
name: Katz, Richard F.
name: Wathen, Andrew J.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Numerical Analysis (math.NA)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Geophysics (physics.geo-ph)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: 65F08, 76M10, 86A17, 86-08

description: This article considers the iterative solution of a finite element discretisation of the magma dynamics equations. In simplified form, the magma dynamics equations share some features of the Stokes equations. We therefore formulate, analyse and numerically test a Elman, Silvester and Wathen-type block preconditioner for magma dynamics. We prove analytically and demonstrate numerically the optimality of the preconditioner. The presented analysis highlights the dependence of the preconditioner on parameters in the magma dynamics equations that can affect convergence of iterative linear solvers. The analysis is verified through a range of two- and three-dimensional numerical examples on unstructured grids, from simple illustrative problems through to large problems on subduction zone-like geometries. The computer code to reproduce all numerical examples is freely available as supporting material.
Explorando o Capital Social em Redes Sociais para Sistemas de Recomendação
Creators: name: De Souza, Paulo Roberto
Publisher: name: Zenodo
Year: 2022

description: Muitas técnicas computacionais têm sido propostas pelas redes sociais para analisar os comportamentos dos usuários a fim de recomendar conteúdo relevante, uma vez que essas redes geram um enorme volume de informação, tornando humanamente impossível de consumir, gerando assim um problema conhecido como sobrecarga de informação. Desta forma, torna-se necessário filtrar a informação relevante para auxiliar os usuários nesta tarefa. Em face dessas informações, as redes sociais possuem muitas características disponíveis, tais como relações e interacções, as auqis podem ser utilizadas para investigar os comportamentos dos usuários em relação a notícias em sua timeline. O valor de uma notícia pode ser definido como Capital Social, o qual é utilizado por este trabalho para modelar as preferências dos usuários. Portanto, este trabalho visa investigar, modelar e quantificar as interacções nas redes sociais, explorando o capital social para desenvolver um sistema de recomendação. Assim, a fim de avaliar as recomendações, foi realizada um experimento online com usuários reais. Por fim, os resultados mostram que a nossa proposta foi capaz de gerar recomendações relevntes em pelo menos 62% dos cenários abordados.
[CII] and 12CO(1-0) Emission Maps in HLSJ091828.6+514223: A Strongly Lensed Interacting System at z=5.24
Creators: name: Rawle, T. D.
name: Egami, E.
name: Bussmann, R. S.
name: Gurwell, M.
name: Ivison, R. J.
name: Boone, F.
name: Combes, F.
name: Danielson, A. L. R.
name: Rex, M.
name: Richard, J.
name: Smail, I.
name: Swinbank, A. M.
name: Altieri, B.
name: Blain, A. W.
name: Clement, B.
name: Dessauges-Zavadsky, M.
name: Edge, A. C.
name: Fazio, G. G.
name: Jones, T.
name: Kneib, J. -P.
name: Omont, A.
name: Perez-Gonzalez, P. G.
name: Schaerer, D.
name: Valtchanov, I.
name: van der Werf, P. P.
name: Walth, G.
name: Zamojski, M.
name: Zemcov, M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present Submillimeter Array (SMA) [CII] 158um and Jansky Very Large Array (JVLA) $^{12}$CO(1-0) line emission maps for the bright, lensed, submillimeter source at $z=5.2430$ behind Abell 773: HLSJ091828.6+514223 (HLS0918). We combine these measurements with previously reported line profiles, including multiple $^{12}$CO rotational transitions, [CI], water and [NII], providing some of the best constraints on the properties of the interstellar medium (ISM) in a galaxy at $z>5$. HLS0918 has a total far-infrared (FIR) luminosity L_FIR(8-1000um) = (1.6$\pm$0.1)x10^14 L_sun/mu, where the total magnification mu_total = 8.9$\pm$1.9, via a new lens model from the [CII] and continuum maps. Despite a HyLIRG luminosity, the FIR continuum shape resembles that of a local LIRG. We simultaneously fit all of the observed spectral line profiles, finding four components which correspond cleanly to discrete spatial structures identified in the maps. The two most redshifted spectral components occupy the nucleus of a massive galaxy, with a source plane separation <1 kpc. The reddest dominates the continuum map (de-magnified L_FIR = (1.1$\pm$0.2)x10^13 L_sun), and excites strong water emission in both nuclear components via a powerful FIR radiation field from the intense star formation. A third star-forming component is most likely a region of a merging companion (dV ~ 500 km/s) exhibiting generally similar gas properties. The bluest component originates from a spatially distinct region, and photo-dissociation region (PDR) analysis suggests that it is lower density, cooler and forming stars less vigorously than the other components. Strikingly, it has very strong [NII] emission which may suggest an ionized, molecular outflow. This comprehensive view of gas properties and morphology in HLS0918 previews the science possible for a large sample of high-redshift galaxies once ALMA attains full sensitivity.
description: 28 pages, 9 figures, accepted in ApJ
Estimating the effectivity of statcheck in peer review to reduce statistical reporting inconsistencies
Creators: name: Nuijten, Michele
name: Wicherts, Jelte
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Social and Behavioral Sciences
subject: statcheck; statistical errors; peer review

description: This is a retrospective observational study in which we compare the prevalence of statistical reporting inconsistencies over time in two journals that implemented statcheck in their peer review process (Psychological Science and the Journal of Experimental Social Psychology) and two matched control journals (the Journal of Experimental Psychology: General and the Journal of Personality and Social Psychology).
Motion-induced radiation from electrons moving in Maxwell's fish-eye
Creators: name: Liu, Yangjie
name: Ang, L. K.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: In uCerenkov radiation and transition radiation, evanescent wave from motion of charged particles transfers into radiation coherently. However, such dissipative motion-induced radiations require particles to move faster than light in medium or to encounter velocity transition to pump energy. Inspired by a method to detect cloak by observing radiation of a fast-moving electron bunch going through it by Zhang {\itshape et al.}, we study the generation of electron-induced radiation from electrons' interaction with Maxwell's fish-eye sphere. Our calculation shows that the radiation is due to a combination of uCerenkov radiation and transition radiation, which may pave the way to investigate new schemes of transferring evanescent wave to radiation.
description: 17 pages, 8 figures, including the Supplementary Information appended in publication. Scientific Reports 2013
Anisotropic AC conductivity of strained graphene
Creators: name: Oliva-Leyva, M.
name: Naumis, Gerardo G.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The density of states and the AC conductivity of graphene under uniform strain are calculated using a new Dirac Hamiltonian that takes into account the main three ingredients that change the electronic properties of strained graphene: the real displacement of the Fermi energy, the reciprocal lattice strain and the changes in the overlap of atomic orbitals. Our simple analytical expressions of the density of states and the AC conductivity generalizes previous expressions only available for uniaxial strain. The results suggest a way to measure the Gruneisen parameter that appears in any calculation of strained graphene, as well as the emergence of a sort of Hall effect due to shear strain.
description: In previous version of our work, a term was missing in equation (17). In version 2, the expression for the AC conductivity of graphene under uniform strain (equation (17)) is corrected. (A corrigendum has been sent to J. Phys.: Condens. Matter)
Current and voltage based bit errors and their combined mitigation for the Kirchhoff-law-Johnson-noise secure key exchange
Creators: name: Saez, Yessica
name: Kish, Laszlo B.
name: Mingesz, Robert
name: Gingl, Zoltan
name: Granqvist, Claes G.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cryptography and Security (cs.CR)
subject: Emerging Technologies (cs.ET)
subject: FOS: Computer and information sciences

description: We classify and analyze bit errors in the current measurement mode of the Kirchhoff-law-Johnson-noise (KLJN) key distribution. The error probability decays exponentially with increasing bit exchange period and fixed bandwidth, which is similar to the error probability decay in the voltage measurement mode. We also analyze the combination of voltage and current modes for error removal. In this combination method, the error probability is still an exponential function that decays with the duration of the bit exchange period, but it has superior fidelity to the former schemes.
description: 9 pages, accepted for publication in Journal of Computational Electronics
One-dimensional $α$ condensation of $α$-linear-chain states in ${^{12}{\rm C}}$ and ${^{16}{\rm O}}$
Creators: name: Suhara, T.
name: Funaki, Y.
name: Zhou, B.
name: Horiuchi, H.
name: Tohsaki, A.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present a new picture that the $α$-linear-chain structure for ${^{12}{\rm C}}$ and ${^{16}{\rm O}}$ has one-dimensional $α$ condensate character. The wave functions of linear-chain states which are described by superposing a large number of Brink wave functions have extremely large overlaps of nearly $100\%$ with single Tohsaki-Horiuchi-Schuck-Röpke (THSR) wave functions, which were proposed to describe the $α$ condensed "gas-like" states. Although this new picture is different from the conventional idea of the spatial localization of $α$ clusters, the density distributions are shown to have localized $α$-clusters which is due to the inter-$α$ Pauli repulsion.
description: 5 pages, 5 figures
Numerical study of magnetization plateaux in the spin-1/2 kagome Heisenberg antiferromagnet
Creators: name: Capponi, Sylvain
name: Derzhko, Oleg
name: Honecker, Andreas
name: Läuchli, Andreas M.
name: Richter, Johannes
Publisher: name: arXiv
Year: 2013
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We clarify the existence of several magnetization plateaux for the kagome $S=1/2$ antiferromagnetic Heisenberg model in a magnetic field. Using approximate or exact localized magnon eigenstates, we are able to describe in a similar manner the plateau states that occur for magnetization per site $m=1/3$, $5/9$, and $7/9$ of the saturation value. These results are confirmed using large-scale Exact Diagonalization on lattices up to 63 sites.
description: 8 pages; minor changes; published version
Uma abordagem baseada em ontologia para auxiliar a aplicação de princípios curriculares orientados a competências em recursos educacionais abertos
Creators: name: Gomes, Edeyson
Publisher: name: Zenodo
Year: 2022
Subjects: Competências
Educação
Ontologia

description: A educação baseada em competências tem atraído a atenção da comunidade de aprendizagem enriquecida por tecnologia, mas apresenta desafios na tradução de princípios curriculares orientados para competências em materiais de aprendizagem concretos. Para mitigar tal desafio, este projeto visa prover um framework de apoio à anotação de recursos educacionais abertos, baseado numa ontologia de competências.
Channel, Phase Noise, and Frequency Offset in OFDM Systems: Joint Estimation, Data Detection, and Hybrid Cramer-Rao Lower Bound
Creators: name: Salim, Omar H.
name: Nasir, Ali A.
name: Mehrpouyan, Hani
name: Xiang, Wei
name: Durrani, Salman
name: Kennedy, Rodney A.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: Oscillator phase noise (PHN) and carrier frequency offset (CFO) can adversely impact the performance of orthogonal frequency division multiplexing (OFDM) systems, since they can result in inter carrier interference and rotation of the signal constellation. In this paper, we propose an expectation conditional maximization (ECM) based algorithm for joint estimation of channel, PHN, and CFO in OFDM systems. We present the signal model for the estimation problem and derive the hybrid Cramer-Rao lower bound (HCRB) for the joint estimation problem. Next, we propose an iterative receiver based on an extended Kalman filter for joint data detection and PHN tracking. Numerical results show that, compared to existing algorithms, the performance of the proposed ECM-based estimator is closer to the derived HCRB and outperforms the existing estimation algorithms at moderate-to-high signal-to-noise ratio (SNR). In addition, the combined estimation algorithm and iterative receiver are more computationally efficient than existing algorithms and result in improved average uncoded and coded bit error rate (BER) performance.
How to use vocabularies to enrich GoTriple ?
Creators: name: Homo, Julien
Publisher: name: Zenodo
Year: 2023
Subjects: Controlled vocabularies
Information architecture
Semantic web

description: The GoTriple platform is a discovery service for SSH publications. During the ingestion pipeline, it transforms metadata records into the Triple Data Model, it performs a series of cleansing, normalization and enrichment procedures - in order to deal with metadata heterogeneity, increase multilingualism and improve content searchability and discoverability - and, finally, it stores and indexes the enriched metadata records, making them searchable via the GoTriple search engine. During this process, many vocabularies are involved having a strategic role in the quality of the results and by extension in the satisfaction of the end users of the platform. What are these vocabularies? Where are they used and how? What are the difficulties encountered in the framework of GoTriple? We will try to answer these questions during the session.
A Rapid Prediction and Response System (RPARS) to Facilitate Guided Self-Regulation During Pandemics
Creators: name: Sweeney, Jeffrey
Publisher: name: Zenodo
Year: 2022
Subjects: Guided Self-Regulation, Privacy Preservation, Agent-based Simulation, Viral Transmission, Digital Technology, Public Health, Pandemic Prevention.

description: It has become imperative to disrupt viral transmission by proactively guiding individual behavior in a targeted approach. While broad population-oriented technologies such as digital contact tracing and vaccine passport apps have been tried, advanced privacy-preserving approaches are needed to ingest user information in real-time, and better adapt to changing epidemiological circumstances. In response, this presentation: 1) introduces guided self-regulation as a possible means of disrupting viral transmission via the use of digital technology, and 2) outlines a prototype Rapid Prediction and Response System designed to facilitate guided self-regulation in an advanced privacy-preserving approach.
description: {"references": ["Sweeney, J., and Vervest, P., \"Disrupting Viral Transmission by Facilitating Guided Self-Regulation\". International Conference on Information Systems (ICIS) 2021 Proceedings. 13. (2021) https://aisel.aisnet.org/icis2021/is_health/is_health/13", "Sweeney, J., Srinivasan, K., and Vervest, P. \"A Rapid Prediction and Response System (RPARS) to Facilitate Guided Self-Regulation During Pandemics\", 17th International Conference on Design Science Research in Information Systems and Technology (2022)"]}
Extraordinary absorption of decorated undoped graphene
Creators: name: Stauber, T.
name: Gómez-Santos, G.
name: de Abajo, F. Javier García
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We theoretically study absorption by an undoped graphene layer decorated with arrays of small particles. We discuss periodic and random arrays within a common formalism, which predicts a maximum absorption of $50\%$ for suspended graphene in both cases. The limits of weak and strong scatterers are investigated and an unusual dependence on particle-graphene separation is found and explained in terms of the effective number of contributing evanescent diffraction orders of the array. Our results can be important to boost absorption by single layer graphene due to its simple setup with potential applications to light harvesting and photodetection based on energy (Förster) rather than charge transfer.
description: 5 pages, 3 figures
Power-law models for infectious disease spread
Creators: name: Meyer, Sebastian
name: Held, Leonhard
Publisher: name: arXiv
Year: 2013
Subjects: subject: Methodology (stat.ME)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Physics and Society (physics.soc-ph)
subject: Applications (stat.AP)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Short-time human travel behaviour can be described by a power law with respect to distance. We incorporate this information in space-time models for infectious disease surveillance data to better capture the dynamics of disease spread. Two previously established model classes are extended, which both decompose disease risk additively into endemic and epidemic components: a spatio-temporal point process model for individual-level data and a multivariate time-series model for aggregated count data. In both frameworks, a power-law decay of spatial interaction is embedded into the epidemic component and estimated jointly with all other unknown parameters using (penalised) likelihood inference. Whereas the power law can be based on Euclidean distance in the point process model, a novel formulation is proposed for count data where the power law depends on the order of the neighbourhood of discrete spatial units. The performance of the new approach is investigated by a reanalysis of individual cases of invasive meningococcal disease in Germany (2002-2008) and count data on influenza in 140 administrative districts of Southern Germany (2001-2008). In both applications, the power law substantially improves model fit and predictions, and is reasonably close to alternative qualitative formulations, where distance and order of neighbourhood, respectively, are treated as a factor. Implementation in the R package surveillance allows the approach to be applied in other settings.
description: Published in at http://dx.doi.org/10.1214/14-AOAS743 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Examining the privilege effect on the achievement gap
Creators: name: Thomas, Garrett M.
Publisher: name: No Publisher Supplied
Year: 2023

description: There is currently much conversation on the issue of the achievement gap as scholars, politicians, and educational leaders continue to grapple with educational inequity and underperformance of students in urban neighborhoods who are mostly Black and Latinx as compared with higher performing students, mostly white, in suburban neighborhoods. This study used qualitative research methods including interviews, focus groups, and artifact collection to conduct a comparative analysis between middle school English Language Arts classes in an underperforming school in Dobytown, N.J. and a high performing, gifted and talented school in the very same neighborhood. Both schools service minority students; but have yielded very different results. Drawing on literature about racism and social justice in education, and using the theoretical perspective of Critical Race Theory as a lens from which to view the data, I gained new insight into the role of privilege in determining the achievement gap as I was able to discover how the humanity of privilege and the dehumanization of underprivilege are major contributing factors. I investigated the teaching methods and approaches used at a gifted and talented school as compared to those employed at an underperforming school to determine to what extent these methods promote or prevent high performance; and I learned how project based learning provides students with analytical skills, critical thinking skills, and problem solving skills that prepare them to be project leaders and leaders in business, politics, and civics. Furthermore, I intended to learn if these practices can be replicated because failure to address the phenomenon of the achievement gap will continue to cause Black and Latinx communities to suffer, academically, economically, socially, and politically. Such social ills burden not just the communities in question, but the entire nation. Amelioration of this phenomenon could only strengthen and be for the benefit of the country.
Correlations in nuclear energy recurrence relations
Creators: name: Buck, B.
name: Merchant, A. C.
name: Perez, S. M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The excitation energies of states belonging to the ground state bands of heavy even-even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree four in the angular momentum.
description: 4 pages, 1 figure, 1 table, 9 references
title: Modelling STEM Teachers’ Pedagogical Content Knowledge in the Framework of the Refined Consensus Model: A Systematic Literature Review
Creators: name: Mientus, Lukas
name: Hume, Anne Christine
name: Wulff, Peter
name: Meiners, Antoinette
name: Borowski, Andreas
Publisher: name: Potsdamer Universität
Year: 2022
Subjects: subject: 370 Bildung und Erziehung

description: Science education researchers have developed a refined understanding of the structure of science teachers’ pedagogical content knowledge (PCK), but how to develop applicable and situation-adequate PCK remains largely unclear. A potential problem lies in the diverse conceptualisations of the PCK used in PCK research. This study sought to systematize existing science education research on PCK through the lens of the recently proposed refined consensus model (RCM) of PCK. In this review, the studies’ approaches to investigating PCK and selected findings were characterised and synthesised as an overview comparing research before and after the publication of the RCM. We found that the studies largely employed a qualitative case-study methodology that included specific PCK models and tools. However, in recent years, the studies focused increasingly on quantitative aspects. Furthermore, results of the reviewed studies can mostly be integrated into the RCM. We argue that the RCM can function as a meaningful theoretical lens for conceptualizing links between teaching practice and PCK development by proposing pedagogical reasoning as a mechanism and/or explanation for PCK development in the context of teaching practice.
description: Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe; 1273
Detecting nonlocality of noisy multipartite states with the CHSH inequality
Creators: name: Chaves, Rafael
name: Acín, Antonio
name: Aolita, Leandro
name: Cavalcanti, Daniel
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The Clauser-Horne-Shimony-Holt inequality was originally proposed as a Bell inequality to detect nonlocality in bipartite systems. However, it can also be used to certify the nonlocality of multipartite quantum states. We apply this to study the nonlocality of multipartite Greenberger-Horne-Zeilinger, W and graph states under local decoherence processes. We derive lower bounds on the critical local-noise strength tolerated by GHZ states before becoming local. In addition, for the whole noisy dynamics, we derive lower bounds on the corresponding nonlocal content for the three classes of states. All the bounds presented can be calculated efficiently and, in some cases, provide significantly tighter estimates than with any other known method. For example, they reveal that $N$-qubit GHZ states undergoing local dephasing are, for all $N$, nonlocal throughout all the dephasing dynamics.
description: 8 pages, 3 figures
A scalable architecture for federated service chaining
Creators: name: Chen, Chen
Publisher: name: Loughborough University
Year: 2022
Subjects: Other information and computing sciences not elsewhere classified

description: The orchestration of Service Function Chain in multiple clouds calls for low-cost, low-latency and scalability. In the existing literature, several techniques have been proposed to meet these requirements. However, how to federate service chains across geo-distributed clouds in light of these requirements remains open. This thesis aims to study how to compose service chains across multiple clouds by considering several factors such as domain autonomy, domain confidential information, scalability, deployment cost, end-to-end latency and dynamic traffic demands. In particular, the proposed schemes in this thesis are devised to improve the most crucial performance metrics: the deployment cost and the end-to-end latency. First, we propose a distributed architecture that jointly considers domain autonomy, domain confidential information and scalability. This architecture enables service chains across multiple administrative domains without revealing sensitive network information such as the domain topology. The proposed architecture significantly reduces the deployment cost which consists of resource and traffic routing costs. Moreover, the proposed architecture remarkably reduces the execution time which suggests that it processes the SFC requests timely. Second, the network traffic is dynamic in nature. To accommodate the varying traffic demand in edge clouds, it is important to dynamically scale VNFs in an agile and efficient manner by considering the resource scarcity at the edge. Hence, we propose a bottleneck-aware VNF scaling and traffic routing algorithm to effectively handle the incoming traffic. The proposed algorithm uses vertical and horizontal scaling in light of the VNF category. The experimental results show that the proposed algorithm efficiently shortens the end-to-end latency, improves the VNF utilization rate and reduces the running time.
Normal pressure effects upon mechanical properties and microstructure of Ti-6Al-4V and AA2024 rotary friction welds
Creators: name: Lakache Houssem Eddine
name: Abdelghani, May
name: Badji Riad
Publisher: name: Faculty of Engineering, Khon Kaen University
Year: 2023
Subjects: Rotary Friction Welding (RFW)
Fracture
Microstructure
Mechanical properties
AA2024
Ti-6Al-4V

description: Engineering and Applied Science Research, 50, 2, 176-184
Exploring changing expectations of middle school families within a COVID-19 context
Creators: name: Schimpf, Kyle
Publisher: name: No Publisher Supplied
Year: 2023

description: It is well documented that effective and responsive middle schools must be set up to support students through numerous changes experienced during adolescence. In practice, however, the work of public schools is not done in a vacuum, and educators must consider parent expectations in decision-making. Meeting the varied needs of adolescent learners and being inclusive of parent expectations are both challenges that have been compounded by the major disruptions to school operations caused by the COVID-19 pandemic. At the research site, Parktown Middle School (PMS) in the Central Atlantic School District (CASD), the challenge of educating during a global health emergency raised the need to better define and understand the expectations of parents, and to identify whether and how parent expectations changed during COVID-19. Research in two fields of study, parent participation in schools and schooling during crises, establishes the importance of studies conducted in local contexts, and reinforces the importance of utilizing parent input when supporting adolescent students. Through a survey, this study surfaced the expectations of PMS parents within the areas of academics, school culture/climate, and school-home relations with consideration for pre-pandemic and COVID-19 contexts. Findings showed that parents held universally high expectations for academic and school culture/climate-based items, and lower priority for school-home relations needs. During the pandemic, there were significant changes to expectations in all three areas, including the softening of academic expectations, a raised level of importance for student wellbeing, and the need for higher levels of communication from school. Focus group input helped to explain survey results, contextualize findings, and reveal just how difficult the COVID-19 school experience was for caretakers and their children. Parents eagerly provided their hopes for the post-pandemic future at PMS, which allows this author, Principal at PMS, to take a critical look at school practices in an effort to align services to the actual needs of families to further balance academic, social, and emotional support. Though specific to a local context, this study should encourage other school leaders to engage their parents to define the expectations they hold for their child’s school experience.
Multiclass learnability and the ERM principle
Creators: name: Daniely, Amit
name: Sabato, Sivan
name: Ben-David, Shai
name: Shalev-Shwartz, Shai
Publisher: name: arXiv
Year: 2013
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: We study the sample complexity of multiclass prediction in several learning settings. For the PAC setting our analysis reveals a surprising phenomenon: In sharp contrast to binary classification, we show that there exist multiclass hypothesis classes for which some Empirical Risk Minimizers (ERM learners) have lower sample complexity than others. Furthermore, there are classes that are learnable by some ERM learners, while other ERM learners will fail to learn them. We propose a principle for designing good ERM learners, and use this principle to prove tight bounds on the sample complexity of learning {\em symmetric} multiclass hypothesis classes---classes that are invariant under permutations of label names. We further provide a characterization of mistake and regret bounds for multiclass learning in the online setting and the bandit setting, using new generalizations of Littlestone's dimension.