cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
On unsteady internal flows of incompressible fluids characterized by implicit constitutive equations in the bulk and on the boundary
Creators: name: Bulíček, Miroslav
name: Málek, Josef
name: Maringová, Erika
Publisher: name: arXiv
Year: 2023
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35Q35, 35Q30 (primary), and 76D03, 76D05 (secondary)

description: Long-time and large-data existence of weak solutions for initial- and boundary-value problems concerning three-dimensional flows of \emph{incompressible} fluids is nowadays available not only for Navier--Stokes fluids but also for various fluid models where the relation between the Cauchy stress tensor and the symmetric part of the velocity gradient is \emph{nonlinear}. The majority of such studies however concerns models where such a dependence is \emph{explicit} (the stress is a function of the velocity gradient), which makes the class of studied models unduly restrictive. The same concerns boundary conditions, or more precisely the slipping mechanisms on the boundary, where the no-slip is still the most preferred condition considered in the literature. Our main objective is to develop a robust mathematical theory for unsteady internal flows of \emph{implicitly constituted} incompressible fluids with implicit relations between the tangential projections of the velocity and the normal traction on the boundary. The theory covers numerous rheological models used in chemistry, biorheology, polymer and food industry as well as in geomechanics. It also includes, as special cases, nonlinear slip as well as stick-slip boundary conditions. Unlike earlier studies, the conditions characterizing admissible classes of constitutive equations are expressed by means of tools of elementary calculus. In addition, a fully constructive proof (approximation scheme) is incorporated. Finally, we focus on the question of uniqueness of such weak solutions.
Determinants of Customer Satisfaction in Travel Agencies: The case of Travelport Ethiopia
Creators: name: Kebede, Lidya
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2018

description: This study aims to identify and assess service quality, product and service features, customer demand fulfillment and customer complain handling system as the determinants of customer satisfaction in travel agencies, the case of Travelport Ethiopia. The study employed explanatory research design, using quantitative methods based on questionnaires collected from the total population of travel agencies in Addis Ababa region. Self-administered questionnaires have been distributed to 410 randomly selected samples and out of this, analysis was made based on the data collected from 370 respondents. The data obtained using this questionnaire were analyzed using Descriptive statistics, Pearson correlation analysis, Data normality test, Multicollinearity test, one way ANOVA analysis , factor analysis and regression with the support of SPSS for analysis and summarization purposes. The psychometric properties of this instrument were assessed using validity and reliability test. This was followed by simultaneous linear regression to identify the most important dimensions of customer satisfaction. The study establishes that service quality, product and service features, customer demand fulfillment and customer complain handling system have all a positive and significant effect on customer satisfaction in Travelport Ethiopia. The study has suggested that Travelport Ethiopia Management must invest on the latest technologies and automate various processes to meet customer satisfaction.
Quantitative characterization of traces of Sobolev maps
Creators: name: Mazowiecka, Katarzyna
name: Van Schaftingen, Jean
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics

description: We give a quantitative characterization of traces on the boundary of Sobolev maps in $\dot{W}^{1,p}(\mathcal M, \mathcal N)$, where $\mathcal{M}$ and $\mathcal{N}$ are compact Riemannian manifolds, $\partial \mathcal{M} \neq \emptyset$: the Borel-measurable maps $u\colon \partial \mathcal M \to \mathcal{N}$ that are the trace of a map $U\in \dot{W}^{1,p}(\mathcal M, \mathcal{N})$ are characterized as the maps for which there exists an extension energy density $w \colon \partial \mathcal{M} \to [0,\infty]$ that controls the Sobolev energy of extensions from $\lfloor p - 1 \rfloor$-dimensional subsets of $\partial \mathcal{M}$ to $\lfloor p\rfloor$-dimensional subsets of $\mathcal{M}$.
description: 26 pages, minor corrections
Heterodyne photodetection measurements on cavity optomechanical systems: Interpretation of sideband asymmetry and limits to a classical explanation
Creators: name: Borkje, Kjetil
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We consider a system where an optical cavity mode is parametrically coupled to a mechanical oscillator. A laser beam driving the cavity at its resonance frequency will acquire red- and blue-shifted sidebands due to noise in the position of the mechanical oscillator. In a classical theory without noise in the electromagnetic field, the powers of these sidebands are of equal magnitude. In a quantum theory, however, an asymmetry between the sidebands can be resolved when the oscillator's average number of vibrational excitations (phonons) becomes small, i.e., comparable to 1. We discuss the interpretation of this sideband asymmetry in a heterodyne photodetection measurement scheme and show that it depends on the choice of detector model. In the optical regime, standard photodetection theory leads to a photocurrent noise spectrum given by normal and time ordered expectation values. The sideband asymmetry is in that case a direct reflection of the quantum asymmetry of the position noise spectrum of the mechanical oscillator. Conversely, for a detector that measures symmetric, non-ordered expectation values, we show that the sideband asymmetry can be traced back to quantum optomechanical interference terms. This ambiguity in interpretation applies not only to mechanical oscillators, but to any degree of freedom that couples linearly to noise in the electromagnetic field. Finally, we also compare the quantum theory to a fully classical model, where sideband asymmetry can arise from classical optomechanical interference terms. We show that, due to the oscillator's lack of zero point motion in a classical theory, the sidebands in the photocurrent spectrum differ qualitatively from those of a quantum theory at sufficiently low temperatures. We discuss the observable consequences of this deviaton between classical and quantum theories.
description: 21 pages + 3 page appendix, 5 figures
Deep reinforced learning heuristic tested on spin-glass ground states: The larger picture
Creators: name: Boettcher, Stefan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: In Changjun Fan et al. [Nature Communications https://doi.org/10.1038/s41467-023-36363-w (2023)], the authors present a deep reinforced learning approach to augment combinatorial optimization heuristics. In particular, they present results for several spin glass ground state problems, for which instances on non-planar networks are generally NP-hard, in comparison with several Monte Carlo based methods, such as simulated annealing (SA) or parallel tempering (PT). Indeed, those results demonstrate that the reinforced learning improves the results over those obtained with SA or PT, or at least allows for reduced runtimes for the heuristics before results of comparable quality have been obtained relative to those other methods. To facilitate the conclusion that their method is ''superior'', the authors pursue two basic strategies: (1) A commercial GUROBI solver is called on to procure a sample of exact ground states as a testbed to compare with, and (2) a head-to-head comparison between the heuristics is given for a sample of larger instances where exact ground states are hard to ascertain. Here, we put these studies into a larger context, showing that the claimed superiority is at best marginal for smaller samples and becomes essentially irrelevant with respect to any sensible approximation of true ground states in the larger samples. For example, this method becomes irrelevant as a means to determine stiffness exponents $θ$ in $d>2$, as mentioned by the authors, where the problem is not only NP-hard but requires the subtraction of two almost equal ground-state energies and systemic errors in each of $\approx 1\%$ found here are unacceptable. This larger picture on the method arises from a straightforward finite-size corrections study over the spin glass ensembles the authors employ, using data that has been available for decades.
description: 5 pages, 2 figures, comment on arXiv:2109.14411, related information can be found at https://physics.emory.edu/faculty/boettcher/
Remnant of binary black-hole mergers: New simulations and peak luminosity studies
Creators: name: Healy, James
name: Lousto, Carlos O.
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We present the results of 61 new simulations of nonprecessing spinning black hole binaries with mass ratios $q=m_1/m_2$ in the range $1/3\leq q\leq1$ and individual spins covering the parameter space $-0.85\leqα_{1,2}\leq0.85$. We additionally perform 10 new simulations of nonspinning black hole binaries with mass ratios covering the range $1/6\leq q<1$. We follow the evolution for typically the last ten orbits before merger down to the formation of the final remnant black hole. This allows for assessment of the accuracy of our previous empirical formulae for relating the binary parameters to the remnant final black hole mass, spin and recoil. We use the new simulation to improve the fit to the above remnant formulae and add a formula for the peak luminosity of gravitational waves, produced around the merger of the two horizons into one. We find excellent agreement (typical errors $\sim0.1-0.2\%$) for the mass and spin, and within $\sim5\%$ for the recoil and peak luminosity. These formulae have direct application to parameter estimation techniques applied to LIGO observations of gravitational waves from binary black hole mergers.
description: 22 pages, 11 figures
Where is the electric current driven in the Blandford-Znajek process?
Creators: name: Toma, Kenji
name: Takahara, Fumio
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The Blandford-Znajek process, the steady electromagnetic energy extraction from a rotating black hole, is widely believed to work for driving relativistic jets, although it is still under debate where the electric current is driven. We address this issue analytically by investigating the time-dependent state in the Boyer-Lindquist and Kerr-Schild coordinate systems. This analysis suggests that a non-ideal magnetohydrodynamic region is required in the time-dependent state, while not in the steady state.
description: 4 pages, 2 figures, contribution to proceedings IAU Symposium No. 324, "New Frontiers in Black Hole Astrophysics", C. Mundell & A. Gomboc, eds
Documentation Matters: Human-Centered AI System to Assist Data Science Code Documentation in Computational Notebooks
Creators: name: Wang, April Yi
name: Wang, Dakuo
name: Drozdal, Jaimie
name: Muller, Michael
name: Park, Soya
name: Weisz, Justin D.
name: Liu, Xuye
name: Wu, Lingfei
name: Dugan, Casey
Publisher: name: arXiv
Year: 2021
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences
subject: H.5.2

description: Computational notebooks allow data scientists to express their ideas through a combination of code and documentation. However, data scientists often pay attention only to the code, and neglect creating or updating their documentation during quick iterations. Inspired by human documentation practices learned from 80 highly-voted Kaggle notebooks, we design and implement Themisto, an automated documentation generation system to explore how human-centered AI systems can support human data scientists in the machine learning code documentation scenario. Themisto facilitates the creation of documentation via three approaches: a deep-learning-based approach to generate documentation for source code, a query-based approach to retrieve online API documentation for source code, and a user prompt approach to nudge users to write documentation. We evaluated Themisto in a within-subjects experiment with 24 data science practitioners, and found that automated documentation generation techniques reduced the time for writing documentation, reminded participants to document code they would have ignored, and improved participants' satisfaction with their computational notebook.
Metaphor and metamorphosis : change and transformation : a visual investigation
Creators: name: Beder, Vita.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
A New Method for the Calculation of Functional and Path Integrals
Creators: name: Hari, Amos A.
name: Givli, Sefi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mathematical Physics (math-ph)
subject: Computation (stat.CO)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: 62-08 (Primary), 65D99 (Secondary)

description: Functional integrals are central to modern theories ranging from quantum mechanics and statistical thermodynamics to biology, chemistry, and finance. In this work we present a new method for calculating functional integrals based on a finite-element formulation. This approach is far more robust, versatile, and powerful than existing methods, thus allowing for more sophisticated computations and the study of problems that could not previously be tackled. Importantly, existing procedures, element libraries and shape functions, which have been developed throughout the years in the context of engineering analysis and partial differential equations, may be directly employed for this purpose.
Consensus based optimization with memory effects: random selection and applications
Creators: name: Borghi, Giacomo
name: Grassi, Sara
name: Pareschi, Lorenzo
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: In this work we extend the class of Consensus-Based Optimization (CBO) metaheuristic methods by considering memory effects and a random selection strategy. The proposed algorithm iteratively updates a population of particles according to a consensus dynamics inspired by social interactions among individuals. The consensus point is computed taking into account the past positions of all particles. While sharing features with the popular Particle Swarm Optimization (PSO) method, the exploratory behavior is fundamentally different and allows better control over the convergence of the particle system. We discuss some implementation aspects which lead to an increased efficiency while preserving the success rate in the optimization process. In particular, we show how employing a random selection strategy to discard particles during the computation improves the overall performance. Several benchmark problems and applications to image segmentation and Neural Networks training are used to validate and test the proposed method. A theoretical analysis allows to recover convergence guarantees under mild assumptions on the objective function. This is done by first approximating the particles evolution with a continuous-in-time dynamics, and then by taking the mean-field limit of such dynamics. Convergence to a global minimizer is finally proved at the mean-field level.
The chaotic dynamics of large-scale structures in a turbulent wake
Creators: name: Varon, Eliott
name: Eulalie, Yoann
name: Edwige, Stephie
name: Gilotte, Philippe
name: Aider, Jean-Luc
Publisher: name: arXiv
Year: 2016
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: The dynamics of a 3D bimodal turbulent wake downstream a square-back Ahmed body are experimentally studied in a wind-tunnel through high-frequency wall pressure probes mapping the rear of the model and a horizontal 2D velocity field. The barycenters of the pressure distribution over the rear part of the model and the intensity recirculation are found highly correlated. Both described the most energetic large-scale structures dynamics, confirming the relation between the large-scale recirculation bubble and its wall pressure foot-print. Focusing on the pressure, its barycenter trajectory has a stochastic behavior but its low frequencies dynamics exhibit the same characteristics as a weak strange chaotic attractor system, with two well defined attractors. The low frequencies dynamics associated to the large-scale structures are then analyzed. The largest Lyapunov exponent is first estimated, leading to a low positive value characteristic of strange attractors and weak chaotic systems. Afterwards, analyzing the autocorrelation function of the time-series, we compute the correlation dimension, larger than two. The signal is finally transformed and analyzed as a telegraph signal showing that its dynamics correspond to a quasi-random telegraph signal. This is the first demonstration that the low frequencies dynamics of a turbulent 3D wake are not a purely stochastic process but rather a weak chaotic process exhibiting strange attractors. From the flow-control point of view, it also opens the path to more simple closed-loop flow control strategies aiming at the stabilization of the wake and the control of the dynamics of the wake barycenter.
description: This second version presents a more detailed study of the wake dynamics, adding sections and references, leading to a slightly revised conclusion. 10 pages, 17 figures
Challenges And Prospects Of Sales Operations Systems In Ethiopian Bottled Water Industries: The Case Of Asku Plc
Creators: name: Getachew, Biniyam
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2019

description: Sales Operations is usually considered as tool towards achieving the objectives commonly shared by business firms, perhaps it is more than anything else in bringing a system to selling. Nevertheless, the activities and functions of sales operations require the direct involvement of many departments other than the sales department. For this and some other related issues, sales operations naturally alive with critical challenges and problems. The objective of this study was to assess the challenges of sales operations systems and investigating the prospects associated with of ASKU PLC. In doing so, both qualitative and quantitative research methods were employed to gather and analyze the necessary data. Structured questionnaires prepared for two categories and direct observations were used to collect primary data and analysis was made with the aid of IBM SPSS version 20. The findings of the study indicated that the overall sales operations system of the company is constrained by many challenges to fully achieve its sales operations plan in which improper planning system took the largest share. However, inefficient sales facilities, poorly arranged working conditions, and unfair and non-uniform product delivery and distribution system were identified as significant challenges. Added to that, growing brand perception of ASKU's natural spring water products, reforms underway to be implemented by the company itself, the nationally witnessed increased demand for bottled water, and the recent decisions made by the company are investigated as major opportunities and prospects of the sales operations systems of ASKU PLC. Prior to anything else, the company is recommended to thrown away the existing methods, systems and approaches of sales operations and management planning to make the sales plan can reconcile both the interests of the company and its customers. More importantly, as far as both the challenges identified and the prospects investigated are more of internal and under control to act on, the company should urgently prepare an action plan so as to make visible changes in the above situations.
NOMA-Based Hybrid Satellite-UAV-Terrestrial Networks for Beyond 5G Maritime Internet of Things
Creators: name: Fang, Xinran
name: Feng, Wei
name: Wang, Yanmin
name: Chen, Yunfei
name: Ge, Ning
name: Ding, Zhiguo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: Current fifth-generation (5G) networks do not cover maritime areas, causing difficulties in developing maritime Internet of Things (IoT). To tackle this problem, we establish a nearshore network by collaboratively using on-shore terrestrial base stations (TBSs) and tethered unmanned aerial vehicles (UAVs). These TBSs and UAVs form virtual clusters in a user-centric manner. Within each virtual cluster, non-orthogonal multiple access (NOMA) is adopted for agilely including various maritime IoT devices, which are usually sparsely distributed on the vast ocean. The nearshore network also shares spectrum with marine satellites. In such a NOMA-based hybrid satellite-UAV-terrestrial network, interference among different network segments, different clusters, as well as different users occurs. We thereby formulate a joint power allocation problem to maximize the sum rate of the network. Different from existing studies, we use large-scale channel state information (CSI) only for optimization to reduce system overhead. The large-scale CSI is obtained by using the position information of maritime IoT devices. The problem is non-convex with intractable non-linear constraints. We tackle these difficulties by adopting the max-min optimization, auxiliary function method, and successive convex approximation technique. An iterative power allocation algorithm is accordingly proposed, which is shown effective for coverage enhancement by simulations. This shows the potential of NOMA-based hybrid satellite-UAV-terrestrial networks for maritime on-demand coverage.
H- Beam formation simulation in negative ion source for CERN's Linac4 accelerator
Creators: name: Vnuchenko, Anna
name: Lettry, Jacques
name: Wünderlich, Dirk
name: Mochalskyy, Serhiy
name: Fantz, Ursel
name: Lindqvist, Max
name: Minea, Tiberiu
name: Revel, Adrien
Publisher: name: arXiv
Year: 2023
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: The caesiated surface negative ion source is the first element of CERN's LINAC4 a linear injector designed to accelerate negative hydrogen ions to 160 MeV. The IS03 ion source is operated at 35 mA beam intensity and reliably feeds CERN's accelerator chain, H- ions are generated via plasma volume and caesiated molybdenum plasma electrode surface mechanisms. Studying the beam extraction region of this H- ion source is essential for optimizing the H- production. The 3D Particle-in-cell Monte Carlo code ONIX (Orsay Negative Ion eXtraction), written to study H- beam formation processes in neutral injectors for fusion, has been adapted to single aperture accelerator H- sources. The code was modified to match the conditions of the beam formation and extraction regions of the Linac4 H- source. A set of parameters was chosen to characterize the plasma and to match the specific volume and surface production modes. Simulated results of the extraction regions are presented and benchmarked with experimental results obtained at the Linac4 test stand.
Stability of the rotation set of area-preserving toral homeomorphisms
Creators: name: Guihéneuf, Pierre-Antoine
name: Koropecki, Andres
Publisher: name: arXiv
Year: 2016
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 37E45, 37E30

description: We show that if the rotation set of a homeomorphism of the torus is stable under small perturbations of the dynamics, then it is a convex polygon with rational vertices. We also show that such homeomorphisms are $C^0$-generic and have bounded rotational deviations (even for pseudo-orbits). The results hold both in the area-preserving setting and in the general setting. When the rotation set is stable, we give explicit estimates on the type of rationals that may appear as vertices of rotation sets in terms of the stability constants.
description: 8 pages, 1 figure. Corrected version, to appear in Nonlinearity
Solitonic self-sustained charge and energy transport on the superconducting cylinder
Creators: name: Canfora, Fabrizio
name: Giacomini, Alex
name: Grandi, Nicolás
name: Oliva, Julio
name: Vera, Aldo
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We present an exact time-dependent solution for a charged scalar field on a two-dimensional cylinder, that can be interpreted as representing a long-standing excitation on a $s$-wave superconducting state, which propagates along a nanotube constructed out of twisted bilayer graphene. The solution has a topological charge characterized by an integer number, which counts the winding of the Higgs phase winds around the cylinder. The resulting electric current generates its own electromagnetic field in a self-consistent way, without the need of any external fields to keep it alive.
description: 9 pages, 6 figures, accepted in Phys. Rev. D
Extended nonergodic states in disordered many-body quantum systems
Creators: name: Torres-Herrera, E. J.
name: Santos, Lea F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: This work supports the existence of extended nonergodic states in the intermediate region between the chaotic (thermal) and the many-body localized phases. These states are identified through an extensive analysis of static and dynamical properties of a finite one-dimensional system with onsite random disorder. The long-time dynamics is particularly sensitive to changes in the spectrum and in the structures of the eigenstates. The study of the evolution of the survival probability, Shannon information entropy, and von Neumann entanglement entropy enables the distinction between the chaotic and the intermediate region.
description: 10 pages, 7 figures, Contribution to the Special Issue "Many-Body Localization" in Annalen der Physik
Memento mori : art, archives and archetypes
Creators: name: McConville, Vicki.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Optofluidic memory and self-induced nonlinear optical phase change for reservoir computing in silicon photonics
Creators: name: Gao, Chengkuan
name: Gaur, Prabhav
name: Almutairi, Dhaifallah
name: Rubin, Shimon
name: Fainman, Yeshaiahu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optics (physics.optics)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Implementing optical-based memory and utilizing it for computation on the nanoscale remains an attractive but still a challenging task. While significant progress was achieved in nanophotonics, allowing to explore nonlinear optical effects and employ light-matter interaction to realize non-conventional memory and computation capabilities, light-liquid interaction was not considered so far as a potential physical mechanism to achieve computation on nanoscale. Here, we experimentally demonstrate self-induced phase change effect which relies on the coupling between geometry changes of thin liquid film to optical properties of photonic modes, and then employ it for neuromorphic computing. In particular, we employ optofluidic Silicon Photonics system in order to demonstrate thermocapillary-based deformation of thin liquid film capable of operating both as a nonlinear actuator and memory element, both residing at the same compact spatial region, thus realizing beyond von Neumann computational architecture. Our experimental results indicate that the magnitude of the nonlinear effect is more than one order of magnitude higher compared to the more traditional heat-based thermo-optical effect, capable to support optically-driven periodic deformation of frequencies of several kHz, and furthermore allows to implement Reservoir Computing at spatial region which is approximately five orders of magnitude smaller compared to state-of-the-art experimental liquid-based systems.
description: 23 pages, 5 figures
Phone and speaker spatial organization in self-supervised speech representations
Creators: name: Riera, Pablo
name: Cerdeiro, Manuela
name: Pepino, Leonardo
name: Ferrer, Luciana
Publisher: name: arXiv
Year: 2023
Subjects: subject: Sound (cs.SD)
subject: Computation and Language (cs.CL)
subject: Audio and Speech Processing (eess.AS)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Self-supervised representations of speech are currently being widely used for a large number of applications. Recently, some efforts have been made in trying to analyze the type of information present in each of these representations. Most such work uses downstream models to test whether the representations can be successfully used for a specific task. The downstream models, though, typically perform nonlinear operations on the representation extracting information that may not have been readily available in the original representation. In this work, we analyze the spatial organization of phone and speaker information in several state-of-the-art speech representations using methods that do not require a downstream model. We measure how different layers encode basic acoustic parameters such as formants and pitch using representation similarity analysis. Further, we study the extent to which each representation clusters the speech samples by phone or speaker classes using non-parametric statistical testing. Our results indicate that models represent these speech attributes differently depending on the target task used during pretraining.
The relation of the seen to the constructed image
Creators: name: Grant, Osian Edmund.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Bahadur efficiency of the maximum likelihood estimator and one-step estimator for quasi-arithmetic means of the Cauchy distribution
Creators: name: Akaoka, Yuichi
name: Okamura, Kazuki
name: Otobe, Yoshiki
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62F10, 62F12, 62E20, 60F10

description: Some quasi-arithmetic means of random variables easily give unbiased strongly consistent closed-form estimators of the joint of the location and scale parameters of the Cauchy distribution. The one-step estimators of those quasi-arithmetic means of the Cauchy distribution are considered. We establish the Bahadur efficiency of the maximum likelihood estimator and the one-step estimators. We also show that the rate of the convergence of the mean-squared errors achieves the Cramer-Rao bound. Our results are also applicable to the circular Cauchy distribution.
description: 23 pages; numerical computations added; to appear in Annals of the Institute of Statistical Mathematics
The Effect of Customer Relationship Marketing on Customer Retention: case of Nyala Insurance S.C
Creators: name: Bekele, Abebaw
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2018

description: In today's highly competitive market structure, winning customers' mind demand to think beyond the current sales volume horizon, and companies deliver superior value to their target customers and provide more satisfaction than its competitors. Otherwise, these customers switch to competitors who can satisfy them more. Reducing customer defections enables to increase future profits. Long-term relationship with customers reduces transaction costs. Thus, lifetime value of a customer is given immense attention. Hence the main purpose of this study is to examine the effect of customer relationship marketing on customer retention in case of Nyala Insurance S.C.. Customer relationship marketing can be measured using the following variables: Trust, Commitment, Satisfaction, Communication and Relationship Benefit. The research is explanatory by nature and it follows a quantitative approach, thus a deductive research approach was used. Data were collected through a five points Likert type summated rating scales of questionnaire. Relatively a large sample of three hundred fifteen was surveyed. Correlational and regression analysis has been deployed to determine the strength of association between the dependent and independent variables. Once the use of these regression and correlation analysis is warranted; that is, after the analysis test is qualified then the coefficient of regression analysis is used to substantiate or disprove the formulated hypothesis.
X-Shooter spectroscopy of young stellar objects - VI - HI line decrements
Creators: name: Antoniucci, S.
name: Nisini, B.
name: Giannini, T.
name: Rigliaco, E.
name: Alcalá, J. M.
name: Natta, A.
name: Stelzer, B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Hydrogen recombination emission lines commonly observed in accreting young stellar objects represent a powerful tracer for the gas conditions in the circumstellar structures. Here we perform a study of the HI decrements and line profiles, from the Balmer and Paschen lines detected in the X-Shooter spectra of a homogeneous sample of 36 T Tauri stars in Lupus, the accretion and stellar properties of which were already derived in a previous work. We aim to obtain information on the gas physical conditions to derive a consistent picture of the HI emission mechanisms in pre-main sequence low-mass stars. We have empirically classified the sources based on their HI line profiles and decrements. We identified four Balmer decrement types (classified as 1, 2, 3, and 4) and three Paschen decrement types (A, B, and C), characterised by different shapes. We first discussed the connection between the decrement types and the source properties and then compared the observed decrements with predictions from recently published local line excitation models. One third of the objects show lines with narrow symmetric profiles, and present similar Balmer and Paschen decrements (straight decrements, types 2 and A). Lines in these sources are consistent with optically thin emission from gas with hydrogen densities of order 10^9 cm^-3 and 5000 11 cm^-3). Type 1 (curved) Balmer decrements are observed only in three sub-luminous sources viewed edge-on, so we speculate that these are actually reddened type 2 decrements. About 20% of the objects present type 3 Balmer decrements (bumpy), which cannot be reproduced with current models.
description: 29 pages, accepted by A&A
General scatterings and electronic states in the quantum-wire network of moiré systems
Creators: name: Hsu, Chen-Hsuan
name: Loss, Daniel
name: Klinovaja, Jelena
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate electronic states in a two-dimensional network consisting of interacting quantum wires, a model adopted for twisted bilayer systems. We construct general operators which describe various scattering processes in the system. In a twisted bilayer structure, the moiré periodicity allows for generalized umklapp scatterings, leading to a class of correlated states at certain fractional fillings. We identify scattering processes which can lead to an insulating gapped bulk with gapless chiral edge modes at fractional fillings, resembling the quantum anomalous Hall effect recently observed in twisted bilayer graphene. Finally, we demonstrate that the description can be useful in predicting spectroscopic and transport features to detect and characterize the chiral edge modes in the moiré-induced correlated states.
description: 15 pages, 7 figures
A Dynamical Systems Approach for Most Probable Escape Paths over Periodic Boundaries
Creators: name: Fleurantin, Emmanuel
name: Slyman, Katherine
name: Barker, Blake
name: Jones, Christopher K. R. T.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 65K10, 11Y16, 60G17, 37J50, 34C45

description: Analyzing when noisy trajectories, in the two dimensional plane, of a stochastic dynamical system exit the basin of attraction of a fixed point is specifically challenging when a periodic orbit forms the boundary of the basin of attraction. Our contention is that there is a distinguished Most Probable Escape Path (MPEP) crossing the periodic orbit which acts as a guide for noisy escaping paths in the case of small noise slightly away from the limit of vanishing noise. It is well known that, before exiting, noisy trajectories will tend to cycle around the periodic orbit as the noise vanishes, but we observe that the escaping paths are stubbornly resistant to cycling as soon as the noise becomes at all significant. Using a geometric dynamical systems approach, we isolate a subset of the unstable manifold of the fixed point in the Euler-Lagrange system, which we call the River. Using the Maslov index we identify a subset of the River which is comprised of local minimizers. The Onsager-Machlup (OM) functional, which is treated as a perturbation of the Friedlin-Wentzell functional, provides a selection mechanism to pick out a specific MPEP. Much of the paper is focused on the system obtained by reversing the van der Pol Equations in time (so-called IVDP). Through Monte-Carlo simulations, we show that the prediction provided by OM-selected MPEP matches closely the escape hatch chosen by noisy trajectories at a certain level of small noise.
description: 28 pages, 15 figures
Effect of iron thicknesses on spin transport in a Fe/Au bilayer system
Creators: name: Briones, J.
name: Weber, M.
name: Stadtmüller, B.
name: Schneider, H. C.
name: Rethfeld, B.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: This paper is concerned with a theoretical analysis of the behavior of optically excited spin currents in bilayer and multilayer systems of ferromagnetic and normal metals. As the propagation, control and manipulation of the spin currents created in ferromagnets by femtosecond optical pulses is of particular interest, we examine the influence of different thicknesses of the constituent layers for the case of electrons excited several electronvolts above the Fermi level. Using a Monte-Carlo simulation framework for such highly excited electrons, we first examine the spatio-temporal characteristics of the spin current density driven in a Fe layer, where the absorption profile of the light pulses plays an important role. Further, we examine how the combination of light absorption profiles, spin-dependent transmission probabilities, and iron layer thicknesses affect spin current density in a Fe/Au bilayer system. For high-energy electrons studied here, the interface and secondary electron generation have a small influence on spin transport in the bilayer system. However, we find that spin injection from one layer to another is most effective within a certain range of iron layer thicknesses.
Effects of gravitational lensing by Kaluza-Klein black holes on neutrino oscillations
Creators: name: Chakrabarty, Hrishikesh
name: Chatrabhuti, Auttakit
name: Malafarina, Daniele
name: Silasan, Bhuddhanubhap
name: Tangphati, Takol
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We study gravitational lensing of neutrinos in a Kaluza-Klein black hole spacetime and compare the oscillation probabilities of neutrinos with the case of lensing by black holes in General Relativity. We show that measuring neutrino oscillations in curved spacetimes may allow us to distinguish the two kinds of black holes. This promises to become an useful tool for future measurements of the properties of black hole candidates and possibly help to constrain the validity of alternative theories of gravity.
description: 13 pages, 6 figures, matches published version
Quenching star formation with low-luminosity AGN winds
Creators: name: Almeida, Ivan
name: Nemmen, Rodrigo
name: Riffel, Rogemar A.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present a simple model for low-luminosity active galactic nucleus (LLAGN) feedback through winds produced by a hot accretion flow. The wind carries considerable energy and deposits it on the host galaxy at kiloparsec scales and beyond, heating the galactic gas thereby quenching star formation. Our model predicts that the typical LLAGN can quench more than $10\%$ of star formation in its host galaxy. We find that long-lived LLAGN winds from supermassive black holes (SMBH) with masses $\geq 10^8 M_{\odot}$ and mass accretion rates $\dot{M} > 10^{-3} \medd \ (0.002 \msun / yr)$ can prevent gas collapse and significantly quench galactic star formation compared to a scenario without AGN, if the wind persists over 1 Myr. For sustained wind production over timescales of 10 Myr or longer, SMBHs with $10^8 M_{\odot}$ or larger masses have important feedback effects with $\dot{M} > 10^{-4} \medd \ (0.0002 \msun / yr)$.
description: Accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal. 7 pages, 5 figures
Archaeoastronomy and the chronology of the Temple of Jupiter at Baalbek
Creators: name: Magli, Giulio
Publisher: name: arXiv
Year: 2016
Subjects: subject: History and Philosophy of Physics (physics.hist-ph)
subject: FOS: Physical sciences

description: One of the most complex architectural feats ever conceived is the magnificent temple of Jupiter at Baalbek, Lebanon. Several issues remain unsolved about this site, and in particular the chronology and dating of the two podia and the true nature of the cult. We present here some hints coming from orientation and from other features of the temple, which seem to point to a unified project of both podia, originally conceived under Herod the Great.
description: Archaeoastronomy/History of Astronomy
Role and Performance of Micro and Small Enterprises in Improving the Standard of Living of Households' Life: the Case of Four Selected Kebeles of Gondar Town
Creators: name: Alamirew, Demis
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2011

description: Overcoming poverty can be possible through establishing MSEs which is one of the strategies adopted in all over the country. MSEs are very essential to create employment opportunities, increase income of households, absorb large labour force, easily adopted and flexible by MSE owners etc. This study investigates the role and performance of MSEs in improving the standard of life of MSE owners in Gondar Town of Amhara Regional State. The main objective of the study was to assess the role of micro and small scale enterprises in the improvement of the standard of MSE owners in Gondar town of Amhara regional state. This study involves 235 questionnaires. In addition, key informant interviews as well as observations were also the other data collection instruments. The questionnaire was distributed to the sample respondents of MSE owners, which are involved in the sector. Based on collected data, the researcher identified the role and performance of the sector as well as the challenges encountered to the MSE owners. Thus, the study revealed that the MSEs sector in terms of employment creation, ensuring their food security, or in improve the life of households become visible and seems potential. It also identified the major determinants of the performance of MSEs, Asset ownership, Income and Food Security situation of respondents and the most serious problems of the MSE sector in the study area: lack of capital and credit, lack production and selling space, lack of market for their products, and dissolving the already established MSE cooperatives etc. In order minimize and alleviate the existed problems, some policy implications are recommended
A search for new physics in central exclusive production using the missing mass technique with the CMS detector and the CMS-TOTEM precision proton spectrometer
Creators: name: CMS Collaboration
name: TOTEM Collaboration
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A generic search is presented for the associated production of a Z boson or a photon with an additional unspecified massive particle X, pp $\to$ pp + Z/$γ$ + X, in proton-tagged events from proton-proton collisions at $\sqrt{s}$ = 13 TeV, recorded in 2017 with the CMS detector and the CMS-TOTEM precision proton spectrometer. The missing mass spectrum is analysed in the 600-1600 GeV range and a fit is performed to search for possible deviations from the background expectation. No significant excess in data with respect to the background predictions has been observed. Model-independent upper limits on the visible production cross section of pp $\to$ pp + Z/$γ$ + X are set.
description: Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/EXO-19-009 (CMS Public Pages)
Everything You Always Wanted to Know About Generalization of Proof Obligations in PDR
Creators: name: Seufert, Tobias
name: Winterer, Felix
name: Scholl, Christoph
name: Scheibler, Karsten
name: Paxian, Tobias
name: Becker, Bernd
Publisher: name: arXiv
Year: 2021
Subjects: subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences

description: In this paper we revisit the topic of generalizing proof obligations in bit-level Property Directed Reachability (PDR). We provide a comprehensive study which (1) determines the complexity of the problem, (2) thoroughly analyzes limitations of existing methods, (3) introduces approaches to proof obligation generalization that have never been used in the context of PDR, (4) compares the strengths of different methods from a theoretical point of view, and (5) intensively evaluates the methods on various benchmarks from hardware model checking as well as from AI planning.