cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Ionized gaseous nebulae chemical abundance determination using the direct method
Creators: name: Pérez-Montero, Enrique
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: In this tutorial it is explained the procedure to analyze an optical emission-line spectrum produced by a nebula ionized by massive star formation. Particularly, it is described the methodology used to derive physical properties, such as electron density and temperature, and the ionic abundances of the most representative elements whose emission lines are present in the optical spectrum. The tutorial is focused on the direct method,based on the measurement of the electron temperature to derive the abundances, given that the ionization and thermal equilibrium of the ionized gas is dominated by the metallicity. The ionization correction factors used to obtain total abundances from the abundances of some of their ions are also given. Finally, some strong-line methods to derive abundances are described. These are used when no estimation of the temperature can be derived, but that can be consistent with the direct method if they are calibrated.
description: 27 pages, 9 figures. Accepted for publication as invited tutorial in PASP. Equation (3.5) relating t(OII) with RO2 corrected. Equation (4.20) for Ne2+ corrected. Some coefs. of the extinction law have been corrected
An agent-based simulation model of pedestrian evacuation based on Bayesian Nash Equilibrium
Creators: name: Wang, Yiyu
name: Ge, Jiaqi
name: Comber, Alexis
Publisher: name: arXiv
Year: 2022
Subjects: subject: Multiagent Systems (cs.MA)
subject: FOS: Computer and information sciences

description: This research incorporates Bayesian game theory into pedestrian evacuation in an agent-based model. Three pedestrian behaviours were compared: Random Follow, Shortest Route and Bayesian Nash Equilibrium (BNE), as well as combinations of these. The results showed that BNE pedestrians were able to evacuate more quickly as they predict congestion levels in their next step and adjust their directions to avoid congestion, closely matching the behaviours of evacuating pedestrians in reality. A series of simulation experiments were conducted to evaluate whether and how BNE affects pedestrian evacuation procedures. The results showed that: 1) BNE has a large impact on reducing evacuation time; 2) BNE pedestrians displayed more intelligent and efficient evacuating behaviours; 3) As the proportion of BNE users rises, average evacuation time decreases, and average comfort level increases. A detailed description of the model and relevant experimental results is provided in this paper. Several limitations as well as further works are also identified.
PrEP Inequities Among Black and Latino MSM in the United States: Identifying Barriers and Opportunities Using a Social Ecological Model (SEM) Framework
Creators: name: Fisher, Ryan
Publisher: name: Georgia State University
Year: 2024

description: 

Human Immunodeficiency Virus (HIV) remains a salient public health priority in the United States. While Pre-Exposure Prophylaxis (PrEP) has existed for HIV prevention efforts since 2012, its effectiveness in epidemic control at the population level relies on the ability of vulnerable populations at increased risk of HIV to access this biomedical intervention. In the United States, most of the new HIV infections in 2021 were among gay and bisexual men, the majority of whom were Black or Hispanic/Latino. This disparity for Black and Latino men who have sex with men (BLMSM) is rooted in deeply entrenched social determinants of health. According to CDC preliminary data published in October 2023, estimates from 2022 suggest 94% of White people who could benefit from PrEP have been prescribed it, but only 13% of Black and 24% of Hispanic/Latino people who could benefit have been prescribed PrEP. To capture the social determinants in PrEP inequities, an environmental scan of published literature pertaining to PrEP access for BLMSM in the U.S. was conducted. The Social Ecological Model (SEM) was utilized to evaluate the root causes of PrEP inequities on four levels: microsystem (individual-level), mesosystem (interpersonal-level), exosystem (community-level), and macrosystem (structural-level).


The results from this scan demonstrate the following windows of opportunity across the four ecological levels to advance PrEP access for BLMSM in the U.S.: 1) Targeted and tailored educational materials to improve individuals perceptions about PrEP 2) PrEP communications delivered by the BLMSM community to eliminate stigma, 3) Provider-targeted LGBTQIA+ affirmative training that is linguistically appropriate with a focus on racial inequities to advance cultural competency and reduce racist biases in medical settings, and 4) Nationwide programs and policies aimed to reduce geographical disparities, alleviate healthcare costs, and address factors associated with immigrant status for foreign-born LMSM.
Distinct turbulence saturation regimes in stellarators
Creators: name: Plunk, G. G.
name: Xanthopoulos, P.
name: Helander, P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: In the complex 3D magnetic fields of stellarators, ion-temperature-gradient turbulence is shown to have two distinct saturation regimes, as revealed by petascale numerical simulations, and explained by a simple turbulence theory. The first regime is marked by strong zonal flows, and matches previous observations in tokamaks. The newly observed second regime, in contrast, exhibits small- scale quasi-two-dimensional turbulence, negligible zonal flows, and, surprisingly, a weaker heat flux scaling. Our findings suggest that key details of the magnetic geometry control turbulence in stellarators.
description: Erratum added to end
Analyzing the Associations between Pre- and Post-COVID-19 Pandemic Childhood ADHD Prevalence, Demographics and Environmental Factors in the United States
Creators: name: Rhodenbaugh, Reisha
Publisher: name: Georgia State University
Year: 2024

description:
Attention-deficit/hyperactivity disorder (ADHD) is a developmental and neurological disorder with no current cure that can cause many difficulties for adults and children [1]. For those with ADHD, they can experience trouble with self-control, paying attention and daily functioning [2]. Specifically for children, ADHD can cause challenges that also directly affect their families and their school experiences [1]. The effects of the COVID-19 pandemic on disorders such as ADHD are still being currently studied, and this project aims to analyze pre- and post-pandemic data to determine any associations with ADHD prevalence and other environmental factors in childrens homes and schools, as well as demographics, across a three-year time period. The data used for this analysis is from the annual National Survey of Childrens Health (NSCH) for years 2019 (n = 29,433), 2020 (n = 42,777) and 2021 (n = 50,892) [3,4]. The NSCH is an annual web and mail-based survey that provides a wealth of information on reported childhood mental and physical health, access to quality health care, and social, community and family background for children in the United States [3]. For the data analysis, original categorical variables from the NSCH datasets like age, sex, race, family income, food insufficiency, household tobacco use, childhood technology use and school safety were used as predictors for modeling. All study variables were associated with the outcome of interest and results were statistically significant. Odds ratios for predictors were summarized across all three years using multiple logistic regression and the results across three years were compared.
The Most Diverse Square Mile in America: Sociodemographic, Health Profiles, and Access to Healthcare among the Refugee, Immigrant, and Migrant Population in Clarkston, Georgia
Creators: name: Thein, Win Min
Publisher: name: Georgia State University
Year: 2024

description: ABSTRACT 

INTRODUCTION: Georgia State University's Prevention Research Center conducted a community needs assessment (CNA) survey in Clarkston, GA to gather data on residents' health, experiences with violence and discrimination, and access to resources such as food, childcare, safe housing, early learning programs, and healthcare.


AIM: This capstone project compared socio-demographic characteristics, health status, and access to healthcare among Clarkston residents using CNA data. It specifically focused on documenting disparities between U.S.-born and foreign-born populations, as well as comparing healthcare access based on English proficiency skills. The long-term goal of these analyses is to identify population needs and provide recommendations for targeted public health interventions and policies.


METHODS: The CNA recruited participants who were < 18 years of age, lived in Clarkston (zip code 30021) and who spoke English, Swahili, Arabic, Dari, Burmese, Amharic, Somali, or Spanish with a target sample size of 250 participants. Recruitment was conducted via electronic flyers shared in the community and local businesses, alongside visual banners and yard signs at survey events and high-traffic areas. Data was collected via Qualtrics and paper surveys and analyzed using SPSS.


RESULTS: About two-thirds of survey respondents were young (18-34). The community is ethnically varied, and many speak languages other than English. Foreign-born residents earn less than $30,000. Although general health profiles are good, foreign-born residents have chronic health issues and substance use differs by nationality. The survey also found that linguistic and cost barriers prevent foreign-born residents from accessing healthcare.


DISCUSSION:


The socio-demographic, health profile, and health access data show that Clarkston's diverse community faces challenges and disparities, particularly foreign-born individuals and those with limited English proficiency. The findings call for policy-level interventions and advocate for a multidimensional and holistic approach that would address both the short-term and the long-term well-being and socio-economic advancement, to achieve the final goal, equity.
Realization of a spontaneous gauge and supersymmetry breaking vacuum
Creators: name: Kobayashi, Tatsuo
name: Omura, Yuji
name: Seto, Osamu
name: Ueda, Kazuki
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It is one of the major issues to realize a vacuum which breaks supersymmetry (SUSY) and R-symmetry, in a supersymmetric model. We study the model, where the same sector breaks the gauge symmetry and SUSY. In general, the SUSY breaking model without gauge symmetry has a flat direction at the minimum of F-term scalar potential. When we introduce U(1) gauge symmetry to such a SUSY breaking model, there can appear a runaway direction. Such a runway direction can be lifted by loop effects, and the gauge symmetry breaking and SUSY breaking are realized. The R-symmetry, that is assigned to break SUSY, is also spontaneously broken at the vacuum. This scenario can be extended to non-Abelian gauge theories. We also discuss application to the Pati-Salam model and the SU(5) grand unified theory. We see that non-vanishing gaugino masses are radiatively generated by the R-symmetry breaking and the gauge messenger contribution.
description: 23 pages, version accepted in JHEP
Topological and quantum critical properties of the interacting Majorana chain model
Creators: name: Chepiga, Natalia
name: Laflorencie, Nicolas
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study Majorana chain with the shortest possible interaction term and in the presence of hoping alternation. When formulated in terms of spins the model corresponds to the transverse field Ising model with nearest-neighbor transverse and next-nearest-neighbor longitudinal repulsion. The phase diagram obtained with extensive DMRG simulations is very rich and contains six phases. Four gapped phases include paramagnetic, period-2 with broken translation symmetry, $\mathbb{Z}_2$ with broken parity symmetry and the $\mathbb{Z}_2$ period-2 phase with both symmetries broken. In addition there are two floating phases: gapless and critical Luttinger liquid with incommensurate correlations, and with an additional spontaneously broken $\mathbb{Z}_2$ symmetry in one of them. By analyzing an extended phase diagram we demonstrate that, in contrast with a common belief, the Luttinger liquid phase along the self-dual critical line terminates at a weaker interaction strength than the end point of the Ising critical line that we find to be in the tri-critical Ising universality class. We also show that none of these two points is a Lifshitz point terminating the incommensurability. In addition, we analyzed topological properties through Majorana zero modes emergent in the two topological phases, with and without incommensurability. In the weak interaction regime, a self-consistent mean-field treatment provides a remarkable accuracy for the description of the spectral pairing and the parity switches induced by the interaction.
description: 34 pages, 18 figures
Scaling laws for non-Hermitian skin effect with long-range couplings
Creators: name: Wang, Yi-Cheng
name: Jen, H. H.
name: You, Jhih-Shih
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Recent years have witnessed a surge of research on the non-Hermitian skin effect (NHSE) in one-dimensional lattices with finite-range couplings. In this work, we show that the long-range couplings that decay as $1/l^α$ at distance $l$ can fundamentally modify the behavior of NHSE and the scaling of quantum entanglement in the presence of nonreciprocity. At $α=0$, the nonlocality of couplings gives rise to the scale-free skin modes, whose localization length is proportional to the system size. Increasing the exponent $α$ drives a complex-to-real spectral transition and a crossover from a scale-free to constant localization length. Furthermore, the scaling of nonequilibrium steady-state entanglement entropy exhibits a subextensive law due to the nonlocality and the complex spectrum, in contrast to an area law arising from NHSE. Our results provide a theoretical understanding on the interplay between long-range couplings and non-Hermiticity.
description: 6 pages, 4 figures
Optimal Trading with a Trailing Stop
Creators: name: Leung, Tim
name: Zhang, Hongzhong
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Finance (q-fin.MF)
subject: FOS: Economics and business
subject: 60G40, 62L15, 91G20, 91G80

description: Trailing stop is a popular stop-loss trading strategy by which the investor will sell the asset once its price experiences a pre-specified percentage drawdown. In this paper, we study the problem of timing buy and then sell an asset subject to a trailing stop. Under a general linear diffusion framework, we study an optimal double stopping problem with a random path-dependent maturity. Specifically, we first derive the optimal liquidation strategy prior to a given trailing stop, and prove the optimality of using a sell limit order in conjunction with the trailing stop. Our analytic results for the liquidation problem is then used to solve for the optimal strategy to acquire the asset and simultaneously initiate the trailing stop. The method of solution also lends itself to an efficient numerical method for computing the the optimal acquisition and liquidation regions. For illustration, we implement an example and conduct a sensitivity analysis under the exponential Ornstein-Uhlenbeck model.
description: 4 figures, 26 pages
Lattice calculation of coordinate-space vector and axial-vector current correlators in QCD
Creators: name: JLQCD Collaboration
name: Tomii, M.
name: Cossu, G.
name: Fahy, B.
name: Fukaya, H.
name: Hashimoto, S.
name: Kaneko, T.
name: Noaki, J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We study the vector and axial-vector current correlators in perturbative and non-perturbative regimes of QCD. The correlators in Euclidean coordinate space are calculated on the lattice using the Möbius domain-wall fermion formulation at three lattice spacings covering 0.044--0.080~fm. The dynamical quark effects of $2+1$ light flavors are included. The sum $V+A$ and the difference $V-A$ of the vector ($V$) and axial-vector ($A$) current correlators calculated on the lattice after extrapolating to the physical point agree with those converted from the ALEPH experimental data of hadronic $τ$ decays. The level of the agreement in the $V+A$ channel is about $1.3σ$ or smaller in the region of $|x|\ge0.4$~fm, while that in the $V-A$ channel is about $1.8σ$ at $|x|=0.74$~fm and smaller at other distances. We also extract the hiral condensate from the short-distance correlators on the lattice using the PCAC relation. Its result extrapolated to the chiral and continuum limit is compatible with other estimates at low energies.
description: 32 pages, 19 figures
On the Trade-off between Over-smoothing and Over-squashing in Deep Graph Neural Networks
Creators: name: Giraldo, Jhony H.
name: Skianis, Konstantinos
name: Bouwmans, Thierry
name: Malliaros, Fragkiskos D.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Graph Neural Networks (GNNs) have succeeded in various computer science applications, yet deep GNNs underperform their shallow counterparts despite deep learning's success in other domains. Over-smoothing and over-squashing are key challenges when stacking graph convolutional layers, hindering deep representation learning and information propagation from distant nodes. Our work reveals that over-smoothing and over-squashing are intrinsically related to the spectral gap of the graph Laplacian, resulting in an inevitable trade-off between these two issues, as they cannot be alleviated simultaneously. To achieve a suitable compromise, we propose adding and removing edges as a viable approach. We introduce the Stochastic Jost and Liu Curvature Rewiring (SJLR) algorithm, which is computationally efficient and preserves fundamental properties compared to previous curvature-based methods. Unlike existing approaches, SJLR performs edge addition and removal during GNN training while maintaining the graph unchanged during testing. Comprehensive comparisons demonstrate SJLR's competitive performance in addressing over-smoothing and over-squashing.
description: This paper has been accepted for publication at the 32nd ACM International Conference on Information and Knowledge Management (CIKM) 2023
Dynamic scaling analysis of the long-range RKKY Ising spin glass Dy$_{x}$Y$_{1-x}$Ru$_{2}$Si$_{2}$
Creators: name: Tabata, Yoshikazu
name: Waki, Takeshi
name: Nakamura, Hiroyuki
Publisher: name: arXiv
Year: 2017
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Dynamic scaling analyses of linear and nonlinear ac susceptibilities in a model magnet of the long-rang RKKY Ising spin glass (SG) Dy$_{x}$Y$_{1-x}$Ru$_{2}$Si$_{2}$ were examined. The obtained set of the critical exponents, $γ$ $\sim$ 1, $β$ $\sim$ 1, $δ$ $\sim$ 2, and $zν$ $\sim$ 3.4, indicates the SG phase transition belongs to a different universality class from either the canonical (Heisenberg) or the short-range Ising SGs. The analyses also reveal a finite-temperature SG transition with the same critical exponents under a magnetic field and the phase transition line $T_{\mbox{g}}(H)$ described by $T_{\mbox{g}}(H)$ $=$ $T_{\mbox{g}}(0)(1-AH^{2/ϕ})$ with $ϕ$ $\sim$ 2. The crossover exponent $ϕ$ obeys the scaling relation $ϕ$ $=$ $γ+ β$ within the margin of errors. These results strongly suggest the spontaneous replica-symmetry-breaking (RSB) with a {\it non- or marginal-mean-field universality class} in the long-range RKKY Ising SG.
description: 9 pages 5 figures
Signatures of a Spin-Active Interface and Locally Enhanced Zeeman field in a Superconductor-Chiral Material Heterostructure
Creators: name: Chen, Cliff
name: Tran, Jason
name: McFadden, Anthony
name: Simmonds, Raymond
name: Saito, Keisuke
name: Chu, En-De
name: Morales, Daniel
name: Suezaki, Varrick
name: Hou, Yasen
name: Aumentado, Joe
name: Lee, Patrick A.
name: Moodera, Jagadeesh S.
name: Wei, Peng
Publisher: name: arXiv
Year: 2024
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A localized Zeeman field, intensified at heterostructure interfaces, could play a crucial role in a broad area including spintronics and unconventional superconductors. Conventionally, the generation of a local Zeeman field is achieved through magnetic exchange coupling with a magnetic material. However, magnetic elements often introduce defects, which could weaken or destroy superconductivity. Alternatively, the coupling between a superconductor with strong spin-orbit coupling and a non-magnetic chiral material could serve as a promising approach to generate a spin active interface. In this study, we leverage an interface superconductor, namely induced superconductivity in noble metal surface states, to probe the spin active interface. Our results unveil an enhanced interface Zeeman field, which selectively closes the surface superconducting gap while preserving the bulk superconducting pairing. The chiral material, i.e. trigonal tellurium, also induces Andreev bound states (ABS) exhibiting spin polarization. The field dependence of ABS manifests a substantially enhanced interface Landé g-factor (g_eff ~ 12), thereby corroborating the enhanced interface Zeeman energy.
description: 27 pages, 11 figures
Total Solar Eclipse White Light Images as a Benchmark for PFSS Coronal Magnetic Field Models: An In-Depth Analysis over a Solar Cycle
Creators: name: Benavitz, Luke Fushimi
name: Boe, Benjamin
name: Habbal, Shadia Rifai
Publisher: name: arXiv
Year: 2024
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Potential Field Source Surface (PFSS) models are widely used to simulate coronal magnetic fields. PFSS models use the observed photospheric magnetic field as the inner boundary condition and assume a perfectly radial field beyond a ``Source Surface" ($R_{ss}$). At present, total solar eclipse (TSE) white light images are the only data that delineate the coronal magnetic field from the photosphere out to several solar radii ($R_\odot$). We utilize a complete solar cycle span of these images between 2008 and 2020 as a benchmark to assess the reliability of PFSS models. For a quantitative assessment, we apply a rolling Hough transform (RHT) to the eclipse data and corresponding PFFS models to measure the difference, $Δθ$, between the data and model magnetic field lines throughout the corona. We find that the average $Δθ$, $\langleΔθ\rangle$, can be minimized for a given choice of $R_{ss}$ depending on the phase within a solar cycle. In particular, $R_{ss}\approx1.3 \ R_\odot$ is found to be optimal for solar maximum, while $R_{ss}\approx3 \ R_\odot$ yields a better match at solar minimum. However, large ($\langleΔθ\rangle>10^\circ$) discrepancies between TSE data and PFSS-generated coronal field lines remain regardless of the choice of source surface. Yet, implementation of solar cycle dependent $R_{ss}$ optimal values do yield more reliable PFSS-generated coronal field lines for use in models and for tracing in-situ measurements back to their sources at the Sun.
description: 21 pages, 16 figures, accepted for publication in ApJ
Entropy of Kerr-de Sitter black hole
Creators: name: Li, Huai-Fan
name: Ma, Meng-Sen
name: Zhang, Li-Chun
name: Zhao, Ren
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Based on the consideration that the black hole horizon and the cosmological horizon of Kerr-de Sitter black hole are not independent each other, we conjecture the total entropy of the system should have an extra term contributed from the correlations between the two horizons, except for the sum of the two horizon entropies. By employing globally effective first law and effective thermodynamic quantities, we obtain the corrected total entropy and find that the region of stable state for kerr-de Sitter is related to the angular velocity parameter $a$, i.e., the region of stable state becomes bigger as the rotating parameters $a$ is increases.
description: 12 pages, 5 figures. arXiv admin note: text overlap with arXiv:1610.09886
Organic Cabbage Production. A Resource Manual for Trainers in Africa
Creators: name: Kadzere, Irene
name: Ssebunya, Brian
name: van den Berge, Paul
name: Weidmann, Gilles
Publisher: name: Zenodo
Year: 2024
Subjects: organic farming
cabbage
Africa
training

description: The manual highlights practical approaches to organic cabbage production in Africa. The manual is intended for use by trainers of trainers and trainers of farmers on organic agriculture.
Integrating Quantum Computing Resources into Scientific HPC Ecosystems
Creators: name: Beck, Thomas
name: Baroni, Alessandro
name: Bennink, Ryan
name: Buchs, Gilles
name: Perez, Eduardo Antonio Coello
name: Eisenbach, Markus
name: da Silva, Rafael Ferreira
name: Meena, Muralikrishnan Gopalakrishnan
name: Gottiparthi, Kalyan
name: Groszkowski, Peter
name: Humble, Travis S.
name: Landfield, Ryan
name: Maheshwari, Ketan
name: Oral, Sarp
name: Sandoval, Michael A.
name: Shehata, Amir
name: Suh, In-Saeng
name: Zimmer, Christopher
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantum Physics (quant-ph)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Quantum Computing (QC) offers significant potential to enhance scientific discovery in fields such as quantum chemistry, optimization, and artificial intelligence. Yet QC faces challenges due to the noisy intermediate-scale quantum era's inherent external noise issues. This paper discusses the integration of QC as a computational accelerator within classical scientific high-performance computing (HPC) systems. By leveraging a broad spectrum of simulators and hardware technologies, we propose a hardware-agnostic framework for augmenting classical HPC with QC capabilities. Drawing on the HPC expertise of the Oak Ridge National Laboratory (ORNL) and the HPC lifecycle management of the Department of Energy (DOE), our approach focuses on the strategic incorporation of QC capabilities and acceleration into existing scientific HPC workflows. This includes detailed analyses, benchmarks, and code optimization driven by the needs of the DOE and ORNL missions. Our comprehensive framework integrates hardware, software, workflows, and user interfaces to foster a synergistic environment for quantum and classical computing research. This paper outlines plans to unlock new computational possibilities, driving forward scientific inquiry and innovation in a wide array of research domains.
Deep Forest
Creators: name: Zhou, Zhi-Hua
name: Feng, Ji
Publisher: name: arXiv
Year: 2017
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences
subject: 68Q32, 68T01

description: Current deep learning models are mostly build upon neural networks, i.e., multiple layers of parameterized differentiable nonlinear modules that can be trained by backpropagation. In this paper, we explore the possibility of building deep models based on non-differentiable modules. We conjecture that the mystery behind the success of deep neural networks owes much to three characteristics, i.e., layer-by-layer processing, in-model feature transformation and sufficient model complexity. We propose the gcForest approach, which generates \textit{deep forest} holding these characteristics. This is a decision tree ensemble approach, with much less hyper-parameters than deep neural networks, and its model complexity can be automatically determined in a data-dependent way. Experiments show that its performance is quite robust to hyper-parameter settings, such that in most cases, even across different data from different domains, it is able to get excellent performance by using the same default setting. This study opens the door of deep learning based on non-differentiable modules, and exhibits the possibility of constructing deep models without using backpropagation.
Axionic Strings, Domain Walls and Baryons
Creators: name: Bigazzi, Francesco
name: Cotrone, Aldo L.
name: Olzi, Andrea
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: When axionic strings carry a global charge, domain walls bounded by such strings may not be allowed to decay completely. This happens in particular in some models where a composite axion-like particle is the pseudo-Nambu-Goldstone boson of chiral symmetry breaking of an extra quark flavor. In this case the global symmetry is the extra flavor baryonic symmetry. The corresponding axionic domain walls can carry a baryonic charge: they represent the low energy description of the baryons made by the extra quark flavor. Basic properties of these particles, such as spin, mass scale, size are discussed. The corresponding charged axionic strings are explicitly constructed and studied in a specific calculable model.
description: Minor changes from the first version, matching the version published in PRD
PREDICTIVE MAINTENANCE OF BALL BEARINGS USING CONVOLUTIONAL NEURAL NETWORKS (CNN)
Creators: name: Derbie, Arsema
name: Temesgen, Kibru
Publisher: name: Zede Journal of Ethiopian Engineers and Architects
Year: 2023

description: To this day, numerous maintenance actions follow preventive and run-to-failure methods. In this work, it has been attempted to show the power of predictive maintenance (PdM) from vibration data using a machine learning technique implementing convolutional neural networks (CNN). Actual data was collected from six different bearings on a machine element fault analysis test rig. The bearings were of the ball bearing type, where one of them was healthy and the rest were faulty at the inner race, the outer race, the rolling element, or a combination of these three, and another had severe damage at either the rolling element or the rings. From the vibration signatures specific to the health status of the bearings, a powerful deep learning convolutional neural network model was built. The model was able to successfully classify the states of bearings with accuracy values ranging between 76.7 and 99.9% based on unseen data. The results indicate that this CNN model can be used as a diagnostic tool for undertaking maintenance operations. KEYWORDS: CNN, predictive maintenance
description: Zede Journal of Ethiopian Engineers and Architects, Vol. 41 (2023): Zede Journal of Ethiopian Engineers and Architects
MODELING AND SIMULATION OF A MICRO-HYDROPOWER SYSTEM FOR RURAL ELECTRIFICATION (A CASE STUDY OF TEMECHA RIVER, AMHARA REGION, ETHIOPIA)
Creators: name: Belie, Getnet
name: Nigussie, Tilahun
Publisher: name: Zede Journal of Ethiopian Engineers and Architects
Year: 2023

description: That there is an imbalance of electricity demand and supply in Ethiopia is known. Development of the Micro hydro power (MHP) system is an important technology to solve the problem. The main objective of this study was to do modelling and simulation of a micro-hydropower system for rural electrification in the case of Temecha River, Ethiopia. Yearly flow data were collected from Ethiopian Basins Development Authority and used to estimate the design flow rate. Next, modelling and simulation were done by using MATLAB SIMULINK. Some of the SIMULINK results were power and flow duration curves, and others. The nethead and design flow rates were found to be16.34m and 0.5731m3/s, respectively. Based on the preliminary analysis, the turbine selected for the site is a Kaplan turbine. It is found that, the power output of this system is greater than the electricity demand of the selected site for 346 days of the year. Thus, the systemic found to be efficient in terms of generated electrical power as compared to similar works reported in the literature. The scale of the design can be re modified to be implemented in other remote are as having river resources. Key words: electrical power, flow rate, Kaplan turbine, MATLAB SIMULINK, MHP, simulation
description: Zede Journal of Ethiopian Engineers and Architects, Vol. 41 (2023): Zede Journal of Ethiopian Engineers and Architects
Infrared thermal imaging camera to measure low temperature thermal fields
Creators: name: Gordiyenko, E.
name: Fomenko, Yu.
name: Shustakova, G.
name: Kovalov, G.
name: Shevchenko, S.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: To measure low-temperature thermal fields, we have developed a single-element cooled thermal imaging camera for a spectral range of 8÷14 μm with an internal shutter for radiometric calibration. To improve the accuracy of measuring the temperature of cold objects, we used a shutter with a combined emissivity as an internal reference source of radiation at the input of the device optical unit. With this aim a small mirror was fixed in the center on its surface covered black, thereby ensuring an efficient reflection of radiation in a wide spectral range of wavelengths. When processing the signal for each pixel of the thermal image, the differential value of the detector response to the shutter blackened and mirror areas was used as a reference. A relative measurement error of 3 percent was obtained for the studied objects with a temperature of -150 °C. The device was successfully used for remote study of thermal field dynamics during freeze-thawing of biological tissues in vivo.
Sparse Bayesian vector autoregressions in huge dimensions
Creators: name: Kastner, Gregor
name: Huber, Florian
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computation (stat.CO)
subject: Econometrics (econ.EM)
subject: Applications (stat.AP)
subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences
subject: FOS: Economics and business

description: We develop a Bayesian vector autoregressive (VAR) model with multivariate stochastic volatility that is capable of handling vast dimensional information sets. Three features are introduced to permit reliable estimation of the model. First, we assume that the reduced-form errors in the VAR feature a factor stochastic volatility structure, allowing for conditional equation-by-equation estimation. Second, we apply recently developed global-local shrinkage priors to the VAR coefficients to cure the curse of dimensionality. Third, we utilize recent innovations to efficiently sample from high-dimensional multivariate Gaussian distributions. This makes simulation-based fully Bayesian inference feasible when the dimensionality is large but the time series length is moderate. We demonstrate the merits of our approach in an extensive simulation study and apply the model to US macroeconomic data to evaluate its forecasting capabilities.
Accurate numerical simulation of moisture front in porous material
Creators: name: Berger, Julien
name: Gasparin, Suelen
name: Dutykh, Denys
name: Mendes, Nathan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Classical Physics (physics.class-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: When comparing measurements to numerical simulations of moisture transfer through porous materials a rush of the experimental moisture front is commonly observed in several works shown in the literature, with transient models that consider only the diffusion process. Thus, to overcome the discrepancies between the experimental and the numerical models, this paper proposes to include the moisture advection transfer in the governing equation. To solve the advection-diffusion differential equation, it is first proposed two efficient numerical schemes and their efficiencies are investigated for both linear and nonlinear cases. The first scheme, Scharfetter-Gummel (SG), presents a Courant-Friedrichs-Lewy (CFL) condition but is more accurate and faster than the second scheme, the well-known Crank-Nicolson approach. Furthermore, the SG scheme has the advantages of being well-balanced and asymptotically preserved. Then, to conclude, results of the convective moisture transfer problem obtained with the SG numerical scheme are compared to experimental data from the literature. The inclusion of an advective term in the model may clearly lead to better results than purely diffusive models.
description: 34 pages, 15 figures, 48 references. Other author's papers can be downloaded at http://www.denys-dutykh.com/
SLAM auto-complete: completing a robot map using an emergency map
Creators: name: Mielle, Malcolm
name: Magnusson, Martin
name: Andreasson, Henrik
name: Lilienthal, Achim J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: In search and rescue missions, time is an important factor; fast navigation and quickly acquiring situation awareness might be matters of life and death. Hence, the use of robots in such scenarios has been restricted by the time needed to explore and build a map. One way to speed up exploration and mapping is to reason about unknown parts of the environment using prior information. While previous research on using external priors for robot mapping mainly focused on accurate maps or aerial images, such data are not always possible to get, especially indoor. We focus on emergency maps as priors for robot mapping since they are easy to get and already extensively used by firemen in rescue missions. However, those maps can be outdated, information might be missing, and the scales of rooms are typically not consistent. We have developed a formulation of graph-based SLAM that incorporates information from an emergency map. The graph-SLAM is optimized using a combination of robust kernels, fusing the emergency map and the robot map into one map, even when faced with scale inaccuracies and inexact start poses. We typically have more than 50% of wrong correspondences in the settings studied in this paper, and the method we propose correctly handles them. Experiments in an office environment show that we can handle up to 70% of wrong correspondences and still get the expected result. The robot can navigate and explore while taking into account places it has not yet seen. We demonstrate this in a test scenario and also show that the emergency map is enhanced by adding information not represented such as closed doors or new walls.
description: 6 pages, 9 figures
FAULT TOLERANT DIGITAL CONTROLLER FOR DC-DC SWITCHING POWER CONVERTER USING MODULAR REDUNDANCY
Creators: name: Dilbie, Daniel
Publisher: name: Zede Journal of Ethiopian Engineers and Architects
Year: 2023

description: Power converters and regulators are the main and critical building blocks of all electronic systems. In applications prone to transient faults, such as particle strikes, spatial redundancy techniques can improve the reliability significantly. The design of a fully digital DC/DC switching buck converter regulator based on a fault tolerant modular redundancy architecture implemented on SRAM FPGAs is presented. Transient events such as single event functional interrupts (SEFIs) are the dominant effects in SRAM-based FPGAs. SEFIs result in missing pulses in the generated PWM control signal of the converter that cause large transient drops at the converter output. In this work, triple modular redundancy (TMR) technique is used to implement spatial redundancy. This approach is used to triplicate the physical digital blocks on FPGA such that faults on one of the modules can be detected and corrected while the system works uninterrupted and with correct output. Experimental results indicate that with triple modular redundancy, the power converter can withstand up to 5x more doze of faults as compared to conventional power converters. Key words: single event functional interrupt (SEFI), fault tolerant design, spatial redundancy, DC/DC switching power converter, buck converter, digital control
description: Zede Journal of Ethiopian Engineers and Architects, Vol. 41 (2023): Zede Journal of Ethiopian Engineers and Architects
Exciton spectrum in atomically thin monolayers: The role of hBN encapsulation
Creators: name: Slobodeniuk, A. O.
name: Molas, M. R.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The high-quality structures containing semiconducting transition metal dichalcogenides (S-TMDs) monolayer (MLs) required for optical and electrical studies are achieved by their encapsulation in hexagonal BN (hBN) flakes. To examine the effect of hBN thickness in these systems, we consider a model with an S-TMD ML placed between a semi-infinite in the out-of-plane direction substrate and complex top cover layers: a layer of finite thickness, adjacent to the ML, and a semi-infinite in the out-of-plane direction top part. We obtain the expression for the Coulomb potential for such a structure. Using this result, we demonstrate that the energies of excitonic $s$ states in the structure with WSe$_2$ ML change significantly for the top hBN with thickness less than 30 layers for different substrate cases, such as hBN and SiO$_2$. For the larger thickness of the top hBN flake, the binding energies of the excitons are saturated to their values of the bulk hBN limit.
description: 7 pages, 4 figures + SM
Imprints of local lightcone projection effects on the galaxy bispectrum. II
Creators: name: Jolicoeur, Sheean
name: Umeh, Obinna
name: Maartens, Roy
name: Clarkson, Chris
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: General relativistic imprints on the galaxy bispectrum arise from observational (or projection) effects. The lightcone projection effects include local contributions from Doppler and gravitational potential terms, as well as lensing and other integrated contributions. We recently presented for the first time, the correction to the galaxy bispectrum from all local lightcone projection effects up to second order in perturbations. Here we provide the details underlying this correction, together with further results and illustrations. For moderately squeezed shapes, the correction to the Newtonian prediction is ~30% on equality scales at z ~ 1. We generalise our recent results to include the contribution, up to second order, of magnification bias (which affects some of the local terms) and evolution bias.
description: 23 pages, 10 figures. Accompanies arXiv:1610.03351. v4 matches published version
Optimal Coordination and Discount Allocation in Residential Renewable Energy Communities with Smart Home Appliances
Creators: name: Conte, Francesco
name: Silvestro, Federico
name: Vinci, Andrea
name: Di Fazio, Anna Rita
Publisher: name: arXiv
Year: 2023
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper proposes an optimal management strategy for a Renewable Energy Community defined according to the Italian legislation. The specific case study is composed by a set of houses equipped with smart appliances, that share a PV plant. The objective is to minimize the cost of electrical energy use for each member of the community, taking into account the discount achievable from government incentives with proper shaping of the community daily consumption. Such incentives are indeed proportional to the shared energy, i.e. the portion of the renewable energy consumed at each hour by community members. The management algorithm allows an optimal coordination of houses power demands, according to the degree of flexibility granted by users. Moreover, a policy to fairly distribute the obtained discount is introduced. Simulation results show the potentialities of the approach.
DAMPING PROPERTIES OF CONCRETE WITH SAND COATED RUBBER AGGREGATES
Creators: name: Gebre, Yisihak
name: Lahmer, Tom
name: Müller, Matthias
name: Tarekegn, Abrham G.
name: Gebreyouhannes, Esayas
Publisher: name: Zede Journal of Ethiopian Engineers and Architects
Year: 2023

description: Waste tire rubber disposal causes major environmental problems and serious threats to human health. A viable solution for reducing waste tire rubber is to reuse the material in concrete production. Since ordinary concrete is brittle, and has low energy absorption capacity, elastic rubber could possibly improve the damping behavior of concrete. In this study, the mechanical and dynamic properties of concrete with partial replacement of coarse aggregate by rubber and epoxy-sand coated rubber at different volume fractions ranging from 5 to 25% were investigated. Test results indicate that uncoated rubber chips in concrete cause a significant reduction in strength. However, epoxy-sand coated rubber aggregate partial replacement improved the interfacial properties of the rubber. Accordingly, an optimum compressive strength was achieved with 15% epoxy-sand coated rubber aggregate replacement. Furthermore, the maximum increment in damping ratios for uncoated and sand-coated rubber aggregates were found to be 58% and 23%, respectively as compared to normal concrete. Hence, the utilization of epoxy sand coated rubber presents a promising approach to enhance the dynamic performance of concrete structures, without affecting their mechanical properties. Key words: waste tire; epoxy, sand coated rubber; damping ratio; dynamic properties
description: Zede Journal of Ethiopian Engineers and Architects, Vol. 41 (2023): Zede Journal of Ethiopian Engineers and Architects
Lorentz invariant entanglement distribution for the space-based quantum network
Creators: name: Byrnes, Tim
name: Ilyas, Batyr
name: Tessler, Louis
name: Takeoka, Masahiro
name: Jambulingam, Segar
name: Dowling, Jonathan P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In recent years there has been a great deal of focus on a globe-spanning quantum network, including linked satellites for applications ranging from quantum key distribution to distributed sensors and clocks. In many of these schemes, relativistic transformations may have deleterious effects on the purity of the distributed entangled pairs. This becomes particularly important for the application of distributed clocks. In this paper, we have developed a Lorentz invariant entanglement distribution protocol that completely removes the effects due to the relative motions of the satellites.