cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Social learning strategies modify the effect of network structure on group performance
Creators: name: Barkoczi, Daniel
name: Galesic, Mirta
Publisher: name: arXiv
Year: 2016
Subjects: subject: Social and Information Networks (cs.SI)
subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: The structure of communication networks is an important determinant of the capacity of teams, organizations and societies to solve policy, business and science problems. Yet, previous studies reached contradictory results about the relationship between network structure and performance, finding support for the superiority of both well-connected efficient and poorly connected inefficient network structures. Here we argue that understanding how communication networks affect group performance requires taking into consideration the social learning strategies of individual team members. We show that efficient networks outperform inefficient networks when individuals rely on conformity by copying the most frequent solution among their contacts. However, inefficient networks are superior when individuals follow the best member by copying the group member with the highest payoff. In addition, groups relying on conformity based on a small sample of others excel at complex tasks, while groups following the best member achieve greatest performance for simple tasks. Our findings reconcile contradictory results in the literature and have broad implications for the study of social learning across disciplines.
title: Business Systems and the Open Method of Co-ordination
title: The EU and Employee Share Ownership in Germany and the UK
titleType: AlternativeTitle
Creators: name: Allen, Matthew M. C.
name: Tüselmann, Heinz-Josef
name: Aldred, Maria L.
Publisher: name: Lucius & Lucius Verlagsgesellschft GmbH
Year: 2009
Subjects: subject: 300
subject: 650

description: Die offene Methode der Koordinierung (OMK) ist ein wichtiger Mechanismus der europäischen Integration. Die PEPPER-Berichte zur Förderung der Gewinn- und Betriebsergebnisbeteiligung der Arbeitnehmer, die von der Europäischen Kommission vorangetrieben werden, können als Beispiel der OMK angesehen werden. In diesem Beitrag wird untersucht, in welchem Maße die institutionellen Unterschiede im Finanz- und Arbeitsmarktsystem in Deutschland und im Vereinigten Königreich die Präferenzen der Sozialpartner beeinflussen und dazu führen, dass die Beteiligung der Arbeitnehmer an Kapitel und Gewinn des Unternehmens in beiden Ländern unterschiedlich angewandt werden. Gezeigt wird, dass die OMK in diesem Bereich ein schwaches Instrument ist, die europäische Integration zu fördern.
description: Arbeit
Prediction of nonlinear interface dynamics in the unidirectional freezing of particle suspensions with rigid compacted layer
Creators: name: Zhang, Tongxin
name: Wang, Zhijun
name: Wang, Lilin
name: Li, Junjie
name: Wang, Jincheng
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Water freezing in particle suspensions widely exists in nature. As a typical physical system of free boundary problem, the spatiotemporal evolution of the solid/liquid interface not only origins from phase transformation but also from permeation flow in front of ice. Physical models have been proposed in previous efforts to describe the interface dynamic behaviors in unidirectional freezing of particle suspensions. However, there are several physical parameters difficult to be determined in previous investigations dedicated to describing the spatiotemporal evolution in unidirectional freezing of particle suspensions. Here, based on the fundamental momentum theorem, we propose a consistent theoretical framework to address the unidirectional freezing process in the particle suspensions coupled with the effect of water permeation. An interface undercooling-dependent pushing force exerted on the compacted layer with a specific formula is derived based on the surface tension. Then a dynamic compacted layer is considered and analyzed. Numerical solutions of the nonlinear models reveal the dependence of system dynamics on some typical physical parameters, particle radius, initial particle concentration in the suspensions, freezing velocity and so on. The system dynamics are characterized by interface velocity, interface undercooling and interface recoil as functions of time. The models allow us to reconsider the formation mechanism of ice spears in freezing of particle suspensions in a simpler but novel way, with potential implications for both understanding and controlling not only ice formation in porous media but also crystallization processes in other complex systems.
The contribution of scalars to ${\cal N}=4$ SYM amplitudes
Creators: name: Bonini, Alfredo
name: Fioravanti, Davide
name: Piscaglia, Simone
name: Rossi, Marco
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: We analyse the contribution of $2n$ scalars to the Operator Product Expansion series for MHV gluon scattering amplitudes/polygonal Wilson loops in planar ${\cal N}=4$ SYM. Hence, we sum up on $2n$ for large coupling $λ$: the logarithm of the amplitude is proportional to $\sqrtλ$, thus competing, unexpectedly, with the famous classical contribution. We give explicit expressions for the first terms at large $λ$ in case of two and four scalars. For finalising this analysis, we find profitable an explicit computation of the $2n$-scalar term at any coupling by means of Young tableaux, paralleling, under certain aspects, the Nekrasov-Okounkov expressions for $\mathcal N =2$ SYM prepotential.
description: 12 pages, typos corrected, final comments and formula (implicit in the previous version) added, published version (Phys. Rev. D)
Two body dynamics in a quadratic modification of general relativity
Creators: name: Bhattacharyya, Soham
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It is shown in this study that deviations from the Einstein-Hilbert action at the quadratic level using a proper analyses and suitable dynamical variables lead to a tiny modification to the post-Newtonian equations of motion, and non-GR-like behavior at very short length scales.
description: 24 pages. Version as accepted as part of the sixteenth Marcel Grossmann conference proceeding
An Index for Ray Operators in 5d $E_n$ SCFTs
Creators: name: Chang, Chi-Ming
name: Ganor, Ori
name: Oh, Jihwan
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We construct an index for BPS operators supported on a ray in five dimensional superconformal field theories with exceptional global symmetries. We compute the $E_n$ representations (for $n=2,\dots,7$) of operators of low spin, thus verifying that while the expression for the index is only SO$(2n-2)\times$U(1) invariant, the index itself exhibits the full $E_n$ symmetry (at least up to the order we expanded). The ray operators we studied in 5d can be viewed as generalizations of operators constructed in a Yang-Mills theory with fundamental matter by attaching an open Wilson line to a quark. For $n\le 7$, in contrast to local operators, they carry nontrivial charge under the $\mathbb{Z}_{9-n}\subset E_n$ center of the global symmetry. The representations that appear in the ray operator index are therefore different, for $n\le 7$, from those appearing in the previously computed superconformal index. For $3\le n\le 7$, we find that the leading term in the index is a character of a minuscule representation of $E_n$. We also discuss the case $n=8$, which presents a unique technical challenge, and remains an open problem.
description: 44 pages, 2 figures
Di-nucleon structures in homogeneous nuclear matter based on two- and three-nucleon interactions
Creators: name: Arellano, H. F.
name: Isaule, Felipe
name: Rios, Arnau
Publisher: name: arXiv
Year: 2016
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We investigate homogeneous nuclear matter within the Brueckner-Hartree-Fock (BHF) approach in the limits of isospin-symmetric nuclear matter (SNM) as well as pure neutron matter at zero temperature. The study is based on realistic representations of the internucleon interaction as given by Argonne v18, Paris, Nijmegen I and II potentials, in addition to chiral N$^{3}$LO interactions, including three-nucleon forces up to N$^{2}$LO. Particular attention is paid to the presence of di-nucleon bound states structures in $^1\textrm{S}_0$ and $^3\textrm{SD}_1$ channels, whose explicit account becomes crucial for the stability of self-consistent solutions at low densities. A characterization of these solutions and associated bound states is discussed. We confirm that coexisting BHF single-particle solutions in SNM, at Fermi momenta in the range $0.13-0.3$~fm$^{-1}$, is a robust feature under the choice of realistic internucleon potentials.
description: 8 pages, 8 figures. Minor corrections. Published in EPJA
The Picard Group of Vertex Affinoids in the First Drinfeld Covering
Creators: name: Taylor, James
Publisher: name: arXiv
Year: 2021
Subjects: subject: Representation Theory (math.RT)
subject: Algebraic Geometry (math.AG)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11S37, 14G22, 14C22

description: Let $F$ be a finite extension of $\mathbb{Q}_p$. Let $Ω$ be the Drinfeld upper half plane, and $Σ^1$ the first Drinfeld covering of $Ω$. We study the affinoid open subset $Σ^1_v$ of $Σ^1$ above a vertex of the Bruhat-Tits tree for $\text{GL}_2(F)$. Our main result is that $\text{Pic}(Σ^1_v)[p] = 0$, which we establish by showing that $\text{Pic}(\mathbf{Y})[p] = 0$ for $\mathbf{Y}$ the Deligne-Lusztig variety of $\text{SL}_2(\mathbb{F}_q)$. One formal consequence is a description of the representation $H^1_{\text{ét}}(Σ^1_v, \mathbb{Z}_p(1))$ of $\text{GL}_2(\mathcal{O}_F)$ as the $p$-adic completion of $\mathcal{O}(Σ^1_v)^\times$.
description: Version 3: final published version
Factors Affecting E-Marketing Adoption In Insurance Industry A Case Study On Ethiopian Insurance Corporation
Creators: name: Desalegn, Dereje
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2019

description: Over the years the internet has steadily become an extremely relevant marketing tool for businesses around the world. So that recent surveys have focused on the adoption of EMarketing in both developed & developing countries. Several opportunities of E-Marketing for companies encompass access to new, untapped markets, overcome distance, work together with governments and contribution in value chains (Business to Business). Indeed there exists a rich benefit of E-Marketing all over the world and even E-Marketing adoption in insurance industry is an important of the social economic development of the country. But, the adoption of EMarketing in insurance industry has been slow. This is attributed to certain E-Marketing adoption factors which have not been fully developed in Ethiopia Context. Therefore, a perspective study uses factors that affect E-Marketing adoption in EIC is necessary to fill in the gap. The main objective of this study was to assess and evaluate the level of E-Marketing adoption in EIC, by trying to distinguish different factors affecting E-Marketing adoption in EIC in order to cite solution. The study employed structured questioner as main research instrument & the target population was the Ethiopian Insurance Corporation Main District 532 employees and the sample size was 132 employees selected for questioner response and 120 of the respondent gave response for the questioner. Descriptive statics was used to summarize the respondents' demographic characteristics. Multiple regression analysis was done and the results showed that generally technological factors, organizational factors and environmental factors (TOE). All have influence on the rate of adoption of E-Marketing in EIC.
Intérêt de la réaction de polymérisation en chaîne (PCR) pour la recherche des légionelles dans l’eau des établissements de santé
Creators: name: Lawrence, Christine
Publisher: name: Health & Co
Year: 2022
Subjects: Legionella
Contamination des eaux
Analyse moléculaire

description: Les cibles génomiques permettant d’identifier le genre Legionella, l’espèce L. pneumophila et L. pneumophila de sérogroupe 1 ont été développées pour le diagnostic de légionellose par PCR dans les prélèvements d’origine pulmonaire. La recherche et l’identification par culture de L. pneumophila dans des échantillons d’eau reposent sur la norme NF T 90-431. L’utilisation des outils de biologie moléculaire pour la recherche de légionelles dans l’eau est principalement freinée par la réglementation sur les contrôles dans les établissements accueillant du public, dont les établissements de santé. Cet outil pourrait cependant être utilisé pour le criblage et pour rechercher des légionelles rapidement autour d’un cas de légionellose.
The Fermi Large Area Telescope as a Galactic Supernovae Axionscope
Creators: name: Meyer, Manuel
name: Giannotti, Maurizio
name: Mirizzi, Alessandro
name: Conrad, Jan
name: Sanchez-Conde, Miguel
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In a Galactic core-collapse supernova (SN), axionlike particles (ALPs) could be emitted via the Primakoff process and eventually convert into $γ$ rays in the magnetic field of the Milky Way. From a data-driven sensitivity estimate, we find that, for a SN exploding in our Galaxy, the Fermi Large Area Telescope (LAT) would be able to explore the photon-ALP coupling down to $g_{aγ} \simeq 2 \times 10^{-13}\,$GeV$^{-1}$ for an ALP mass $m_a \lesssim 10^{-9}\,$eV. These values are out of reach of next generation laboratory experiments. In this event, the Fermi LAT would probe large regions of the ALP parameter space invoked to explain the anomalous transparency of the Universe to $γ$ rays, stellar cooling anomalies, and cold dark matter. If no $γ$-ray emission were to be detected, Fermi-LAT observations would improve current bounds derived from SN1987A by more than one order of magnitude.
description: 6 pages, 2 figures. Published in PRL
Impact of Service Quality on Customer Satisfaction: The Case of Bank of Abyssinia S.C
Creators: name: Melaku, Meron
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2015

description: Banks play a very important role in the economic life of a nation. Although the banking industry is growing and offering various types of financial services to the public, their mere existence does not do any good unless they deliver a quality service. This study is set out to examine the impact of service quality on customer satisfaction in Bank of Abyssinia S.C. SERVPERF model by Cronin and Taylor's(1992) is used to identify the relationship. Quantitative means of data collection method is employed to collect the data through questionnaire. Proportionate and disproportionate stratified sampling technique is used to select the sample size and a sample of 399 bank customers are taken to undertake the study. The data collected from the questionnaire were analyzed using statistical tools such as mean, correlation, and regression analysis VIA SPSS Version. The results of this study indicate that, all the service quality dimensions (tangibility, reliability, responsiveness, empathy and assurance) have positive and significant relationship with customer satisfaction. Also the finding of this study indicates that customers were most satisfied with the assurance dimensions of service quality followed by responsiveness. Accordingly from the regression result it is observed that all service quality dimensions have positive and significant impact on customer satisfaction. Furthermore, 44% of the variations in customer satisfaction is explained by service quality dimensions in bank of Abyssinia S.C. Based on the findings of the study, the researcher forwarded some recommendations to the bank's management. Key Words: Service Quality, Customer Satisfaction
Holographic 3d $\mathcal N=1$ Conformal Manifolds
Creators: name: Bobev, Nikolay
name: Gautason, Fridrik Freyr
name: van Muiden, Jesse
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We construct and study several examples of continuous families of AdS$_4$ $\mathcal N = 1$ solutions of four-dimensional maximal gauged supergravity. These backgrounds provide the holographic descriptions of conformal manifolds of the dual 3d $\mathcal N = 1$ SCFTs. The solutions we study can be uplifted to type IIB supergravity where they arise from D3-branes wrapping an $S^1$ with an S-duality twist. We find the spectrum of low lying operators in the 3d $\mathcal N = 1$ SCFTs as a function of the exactly marginal coupling and discuss the structure of the corresponding superconformal multiplets. Using string theory techniques we also study additional examples of continuous families of $\mathcal N = 1$ AdS$_4$ vacua in type IIB and massive type IIA supergravity.
description: 37 pages
Tracing space: a generic city of the imagination : a dialogue between 2D art and 3D architectural forms
Creators: name: Poljski, Caterina.
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.
Challenges and Prospects of Outsourcing: the Case of Commercial Bank of Ethiopia
Creators: name: Maru, Abebe
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2015

description: The purpose of this research is to assess the challenges and prospects of outsourcing the security, messenger and janitorial services in commercial bank of Ethiopia and to come up with the possible solution to minimize the existing problems. The study covers CBE branches under west Addis district and the outsourcing administrative office. The researcher used both qualitative and quantitative data collected through questionnaires, interview, and review of CBE service level agreement document. The findings of the study show that the outsourced services enabled the bank to save managers time, give more attention for the core functions of the bank rather than non core areas and expand its branch aggressively. On the contrary defining SLA, selecting the right vendor, loss of direct controlling and measuring service qualities were the challenges of the bank as the result of outsourced services. In addition to these, employees of the service provider were not properly trained about their job, lack motivation and belongingness, not properly equipped with materials that help to perform their job. Thus, the performance of the service provider was not as per service level agreement. Finally, it is recommended that commercial bank of Ethiopia should deal with the service provider to revise the service level agreement and enforce the service provider to facilitate the necessary training to improve employees' skill and to provide working materials for a particular job. The bank also need to follow up the service quality as per SLA and check the amount of commission that the service provider collect from each employees monthly salary as compare with the bank paid to the service provider per individual employee
Lattice operators for scattering of particles with spin
Creators: name: Prelovsek, S.
name: Skerbis, U.
name: Lang, C. B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We construct operators for simulating the scattering of two hadrons with spin on the lattice. Three methods are shown to give the consistent operators for PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar, vector and nucleon. Explicit expressions for operators are given for all irreducible representations at lowest two relative momenta. Each hadron has a good helicity in the first method. The hadrons are in a certain partial wave L with total spin S in the second method. These enable the physics interpretations of the operators obtained from the general projection method. The correct transformation properties of the operators in all three methods are proven. The total momentum of two hadrons is restricted to zero since parity is a good quantum number in this case.
description: 29 pages, updated to match the version published by JHEP. The relation between partial-wave and helicity operators is now provided (Eq. 4.13) and proved (Appendix D). Discussions on the applicability of the constructed operators and higher partial-waves have been extended
Well-posedness of the Lenard-Balescu equation with smooth interactions
Creators: name: Duerinckx, Mitia
name: Winter, Raphael
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: The Lenard-Balescu equation was formally derived in the 1960s as the fundamental description of the collisional process in a spatially homogeneous system of interacting particles. It can be viewed as correcting the standard Landau equation by taking into account collective screening effects. Due to the reputed complexity of the Lenard-Balescu equation in case of Coulomb interactions, its mathematical theory has remained void apart from the linearized setting. In this contribution, we focus on the case of smooth interactions and we show that dynamical screening effects can then be handled perturbatively. Taking inspiration from the Landau theory, we establish global well-posedness close to equilibrium, local well-posedness away from equilibrium, and we discuss the convergence to equilibrium and the validity of the Landau approximation.
description: 46 pages
Ratios of Charged Antiparticles-to-Particles near Mid-Rapidity in Au + Au Collisions at sqrt(sNN) = 130 GeV
Creators: name: Back, B. B.
name: Baker, M. D.
name: Barton, D. S.
name: Betts, R. R.
name: Bindel, R.
Publisher: name: The American Physical Society
Year: 2001
Subjects: subject: 530

description: Physical Review Letters
Measurement of the High Energy Two-Body Deuteron Photodisintegration Differential Cross Section
Creators: name: Ahmidouch, A.
name: Armstrong, C. S.
name: Arrington, J.
name: Asaturyan, R.
name: Schulte, E. C.
Publisher: name: The American Physical Society
Year: 2001
Subjects: subject: 530

description: Physical Review Letters
Australian and Greek : synthesising two lived cultures as contemporary art
Creators: name: Varellas, Dorothy.
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.
Topological features of vector vortex beams perturbed with uniformly polarized light
Creators: name: D'Errico, Alessio
name: Maffei, Maria
name: Piccirillo, Bruno
name: de Lisio, Corrado
name: Cardano, Filippo
name: Marrucci, Lorenzo
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Optical singularities manifesting at the center of vector vortex beams are unstable, since their topological charge is higher than the lowest value permitted by Maxwell's equations. Inspired by conceptually similar phenomena occurring in the polarization pattern characterizing the skylight, we show how perturbations that break the symmetry of radially symmetric vector beams lead to the formation of a pair of fundamental and stable singularities, i.e. points of circular polarization. We prepare a superposition of a radial (or azimuthal) vector beam and a uniformly linearly polarized Gaussian beam; by varying the amplitudes of the two fields, we control the formation of pairs of these singular points and their spatial separation. We complete this study by applying the same analysis to vector vortex beams with higher topological charges, and by investigating the features that arise when increasing the intensity of the Gaussian term. Our results can find application in the context of singularimetry, where weak fields are measured by considering them as perturbation of unstable optical beams.
Possibility to Deduce the Emission Time Sequence of Neutrons and Protons from the Neutron-Proton Correlation Function
Creators: name: Anzalone, A.
name: Colonna, N.
name: Ghetti, R.
name: Helgesson, J.
name: Jakobsson, B.
Publisher: name: The American Physical Society
Year: 2001
Subjects: subject: 530

description: Physical Review Letters
Nonlinear optimization of district heating networks
Creators: name: Krug, Richard
name: Mehrmann, Volker
name: Schmidt, Martin
Publisher: name: Technische Universität Berlin
Year: 2020
Subjects: subject: 500 Naturwissenschaften und Mathematik::510 Mathematik::510 Mathematik
subject: district heating networks
subject: nonlinear optimization
subject: Euler equations
subject: differential-algebraic equations
subject: mixing
subject: complementarity constraints

description: We develop a complementarity-constrained nonlinear optimization model for the time-dependent control of district heating networks. The main physical aspects of water and heat flow in these networks are governed by nonlinear and hyperbolic 1d partial differential equations. In addition, a pooling-type mixing model is required at the nodes of the network to treat the mixing of different water temperatures. This mixing model can be recast using suitable complementarity constraints. The resulting problem is a mathematical program with complementarity constraints subject to nonlinear partial differential equations describing the physics. In order to obtain a tractable problem, we apply suitable discretizations in space and time, resulting in a finite-dimensional optimization problem with complementarity constraints for which we develop a suitable reformulation with improved constraint regularity. Moreover, we propose an instantaneous control approach for the discretized problem, discuss practically relevant penalty formulations, and present preprocessing techniques that are used to simplify the mixing model at the nodes of the network. Finally, we use all these techniques to solve realistic instances. Our numerical results show the applicability of our techniques in practice.
On some hyperelliptic Hurwitz-Hodge integrals
Creators: name: Lewański, Danilo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Algebraic Geometry (math.AG)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: This short note addresses Hodge integrals over the hyperelliptic locus. Recently Afandi computed, via localisation techniques, such one-descendant integrals and showed that they are Stirling numbers. We give another proof of the same statement by a very short argument, exploiting Chern classes of spin structures and relations arising from Topological Recursion in the sense of Eynard and Orantin. These techniques seem also suitable to deal with three orthogonal generalisations: 1. the extension to the r-hyperelliptic locus, 2. the extension to an arbitrary number of non-Weierstrass pairs of points, 3. the extension to multiple descendants.
description: 10 pages
Alternatives to the EM algorithm for ML estimation of location, scatter matrix, and degree of freedom of the Student t distribution
Creators: name: Hasannasab, Marzieh
name: Hertrich, Johannes
name: Laus, Friederike
name: Steidl, Gabriele
Publisher: name: Technische Universität Berlin
Year: 2020
Subjects: subject: 500 Naturwissenschaften und Mathematik::510 Mathematik::510 Mathematik
subject: accelerated EM algorithm
subject: student t distribution
subject: image denoising
subject: robust denoising
subject: ML estimators
subject: cauchy noise
subject: nonlocal myriad filters

description: In this paper, we consider maximum likelihood estimations of the degree of freedom parameter ν, the location parameter μ and the scatter matrix Σ of the multivariate Student t distribution. In particular, we are interested in estimating the degree of freedom parameter ν that determines the tails of the corresponding probability density function and was rarely considered in detail in the literature so far. We prove that under certain assumptions a minimizer of the negative log-likelihood function exists, where we have to take special care of the case ν→∞, for which the Student t distribution approaches the Gaussian distribution. As alternatives to the classical EM algorithm we propose three other algorithms which cannot be interpreted as EM algorithm. For fixed ν, the first algorithm is an accelerated EM algorithm known from the literature. However, since we do not fix ν, we cannot apply standard convergence results for the EM algorithm. The other two algorithms differ from this algorithm in the iteration step for ν. We show how the objective function behaves for the different updates of ν and prove for all three algorithms that it decreases in each iteration step. We compare the algorithms as well as some accelerated versions by numerical simulation and apply one of them for estimating the degree of freedom parameter in images corrupted by Student t noise.
Integration of a Building Energy Model in an Urban Climate Model and its Application
Creators: name: Jin, Luxi
name: Schubert, Sebastian
name: Fenner, Daniel
name: Meier, Fred
name: Schneider, Christoph
Publisher: name: Technische Universität Berlin
Year: 2020
Subjects: subject: 500 Naturwissenschaften und Mathematik::550 Geowissenschaften, Geologie::550 Geowissenschaften
subject: building energy model
subject: citizen weather station
subject: COSMO-CLM
subject: indoor temperature
subject: urban heat island

description: We report the ability of an urban canopy model, coupled with a regional climate model, to simulate energy fluxes, the intra-urban variability of air temperature, urban-heat-island characteristics, indoor temperature variation, as well as anthropogenic heat emissions, in Berlin, Germany. A building energy model is implemented into the Double Canyon Effect Parametrization, which is coupled with the mesoscale climate model COSMO-CLM (COnsortium for Small-scale MOdelling in CLimate Mode) and takes into account heat generation within buildings and calculates the heat transfer between buildings and the urban atmosphere. The enhanced coupled urban model is applied in two simulations of 24-day duration for a winter and a summer period in 2018 in Berlin, using downscaled reanalysis data to a final grid spacing of 1 km. Model results are evaluated with observations of radiative and turbulent energy fluxes, 2-m air temperature, and indoor air temperature. The evaluation indicates that the improved model reproduces the diurnal characteristics of the observed turbulent heat fluxes, and considerably improves the simulated 2-m air temperature and urban heat island in winter, compared with the simulation without the building energy model. Our set-up also estimates the spatio–temporal variation of wintertime energy consumption due to heating with canyon geometry. The potential to save energy due to the urban heat island only becomes evident when comparing a suburban site with an urban site after applying the same grid-cell values for building and street widths. In summer, the model realistically reproduces the indoor air temperature and its temporal variation.
Dynamic flows with adaptive route choice
Creators: name: Graf, Lukas
name: Harks, Tobias
name: Sering, Leon
Publisher: name: Technische Universität Berlin
Year: 2020
Subjects: subject: 500 Naturwissenschaften und Mathematik::510 Mathematik::510 Mathematik
subject: dynamic flows
subject: flows over time
subject: equilibria
subject: networks

description: We study dynamic network flows and introduce a notion of instantaneous dynamic equilibrium (IDE) requiring that for any positive inflow into an edge, this edge must lie on a currently shortest path towards the respective sink. We measure current shortest path length by current waiting times in queues plus physical travel times. As our main results, we show: existence and constructive computation of IDE flows for multi-source single-sink networks assuming constant network inflow rates,finite termination of IDE flows for multi-source single-sink networks assuming bounded and finitely lasting inflow rates,the existence of IDE flows for multi-source multi-sink instances assuming general measurable network inflow rates,the existence of a complex single-source multi-sink instance in which any IDE flow is caught in cycles and flow remains forever in the network.
Determinants of Savings and Credit Cooperatives Societies (SACCOs) outreach in Addis Ababa.
Creators: name: Dibissa, Nigusie
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2015

description: The main purpose of this study was to examine Determinants of Saving and credit cooperatives (SACCOs) outreach in Addis Ababa. The study followed quantitative research approach and explanatory research design. Using purposive sampling, 32 SACCOs were taken from 235 affiliated members of AASCCOU. Data used in the analysis comprises secondary data and also panel data regression model is used for the analysis. The major determinant factors that affect outreach of SACCOS by taking loan size as a measurement are amount of saving, level of interest rate on saving, amount of dividend paid to members which has a positive relationship and statistically significant and the others determinants that have positive relationship but statistically insignificant are age of SACCO's, income per capital and maturity date. On the other hand when number of SACCO's member is taken amount of saving and income per capital has positive relationship and significantly affects SACCOs outreach. Similarly age of SACCOs, dividend paid to members and maturity date affects number of SACCO's members positively but they are insignificant. In addition the major determinant factor that negatively affects loan size and statistically significant is level of interest rate on borrowing. In the same way MEMB is affected negatively by LIB and LIS negatively but its significance level is weak. Therefore the researcher recommends SACCOS should give high attention in attracting members to increase their source of fund by providing awareness about the benefit of joining SACCOS, by using social medias, providing training to clients, by distributing brochure for clients, if fund is available should encourage members to take loan to increase dividend for idle funds, should charge compatible interest rate on loan to members to attract members, should increase the duration of repayment of loan and finally Federal cooperatives agency should pay attention in continuous supervision of SACCOs. Key terms: outreach, SACCOs' Determinants, Loan outstanding and number of members
Covariant Star Product on Semi-Conformally Flat Noncommutative Calabi-Yau Manifolds and Noncommutative Topological Index Theorem
Creators: name: Varshovi, A. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A differential geometric version of noncommutative topological index theorem is worked out for covariant star products on noncommutative vector bundles. For start, a noncommutative manifold is considered as a product space X = Y * Z, wherein Y is a closed manifold, and Z is a flat Calabi-Yau m-fold. Also a semi-conformally flat metric is considered for X which leads to a dynamical noncommutative spacetime from the viewpoint of noncommutative gravity. Based on the Kahler form of Z the noncommutative star product is defined covariantly on vector bundles over X. This covariant star product leads to the celebrated Groenewold-Moyal product for trivial vector bundles and their flat connections, such as C^\infty(X). Hereby, the noncommutative characteristic classes are defined properly and the noncommutative Chern-Weil theory is established by considering the covariant star product and the superconnection formalism. Finally, the index of the noncommutative version of elliptic operators is studied and the noncommutative topological index theorem is stated accordingly.
description: 31 pages
Holographic Renormalization of Einstein-Maxwell-Dilaton Theories
Creators: name: Kim, Bom Soo
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We generalize the boundary value problem with a mixed boundary condition that involves the gauge and scalar fields in the context of Einstein-Maxwell-Dilaton theories. In particular, the expectation value of the dual scalar operator can be a function of the expectation value of the current operator. The properties are prevalent in a fixed charge ensemble because the conserved charge is shared by both fields through the dilaton coupling, which is also responsible for non-Fermi liquid properties. We study the on-shell action and the stress energy tensor to note practical importances of the boundary value problem. In the presence of the scalar fields, physical quantities are not fully fixed due to the finite boundary terms that manifest in the massless scalar or the scalar with mass saturating the Breitenlohner-Freedman bound.
description: 39+1 pages. Improved discussions, typos fixed and references added
Evidence for Droplet Reorientation and Interfacial Charges in a Polymer-Dispersed Liquid-Crystal Cell
Creators: name: Jain, P. C.
name: Sharma, S. C.
name: Tapiawala, A. J.
name: Zhang, L.
Publisher: name: The American Physical Society
Year: 2001
Subjects: subject: 530

description: Physical Review Letters
Mesoscopic and macroscopic quantum correlations in photonic, atomic and optomechanical systems
Creators: name: Teh, Run Yan
name: Rosales-Zárate, Laura
name: Drummond, Peter D.
name: Reid, M. D.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: This paper reviews the progress that has been made in our knowledge of quantum correlations at the mesoscopic and macroscopic level. We begin by summarizing the Einstein-Podolsky-Rosen (EPR) argument and the Bell correlations that cannot be explained by local hidden variable theories. It was originally an open question as to whether (and how) such quantum correlations could occur on a macroscopic scale, since this would seem to counter the correspondence principle. The purpose of this review is to examine how this question has been answered over the decades since the original papers of EPR and Bell. We first review work relating to higher spin measurements which revealed that macroscopic quantum states could exhibit Bell correlations. This covers higher dimensional, multi-particle and continuous-variable EPR and Bell states where measurements on a single system give a spectrum of outcomes, and also multipartite states where measurements are made at multiple separated sites. It appeared that the macroscopic quantum observations were for an increasingly limited span of measurement settings and required a fine resolution of outcomes. Motivated by this, we next review correlations for macroscopic superposition states, and examine predictions for the violation of Leggett-Garg inequalities for dynamical quantum systems. These results reveal Bell correlations for coarse-grained measurements which need only distinguish between macroscopically distinct states, thus bringing into question the validity of certain forms of macroscopic realism. Finally, we review progress for massive systems, including Bose-Einstein condensates and optomechanical oscillators, where EPR-type correlations have been observed between massive systems. Experiments are summarized, which support the predictions of quantum mechanics in mesoscopic regimes.
دور الحوكمة والمسؤولية الاجتماعية في تحسين أداء المؤسسات الصناعية بالجزائر(دراسة حالة مؤسسة "أن سي أ رويبة" الجزائر)
Creators: name: خلوفي, سفيان
Publisher: name: figshare
Year: 2023
Subjects: Corporate governance
Corporate social responsibility

description: تهدف هذه الدراسة إلى التعرف على الدور الذي تلعبه كل من الحوكمة والمسؤولية الاجتماعية للمؤسسات في تحسين أداء المؤسسات الصناعية الجزائرية من خلال عرض دراسة حالة لمؤسسة صناعية جزائرية هي مؤسسة "أن سي أ رويبة" ، بحيث تم عرض مختلف مظاهر تطبيق معايير ومبدأ الحوكمة والمسؤولية الاجتماعية للمؤسسة خلال السنوات الأخيرة ،كما تم عرض بعض مؤشرات الأداء حسب أخر التقارير المالية الخاصة بالمؤسسة وكذا بعض المعطيات التي تم الحصول عليها من الموقع الالكتروني لبورصة الجزائر، وتوصلت الدراسة إلى أن الحوكمة والمسؤولية الاجتماعية تلعبان دور كبير في تشجيع الاستثمار الأمثل والأرشد للموارد المتاحة، من خلال تهيئة مناخ الأعمال وفق بيئة أساسها المسؤولية والرقابة والالتزام ومراعاة مبادئ الوضوح والشفافية في رسم أهداف وخطط الشركة الإستراتيجية، وبيان حقوق كياناتها والتزاماتها، وإدارة علاقتها مع جميع أصحاب المصلحة كالموردين والممولين والمستهلكين وجهات الرقابة وغيرهم، وأوصت هذه الدراسة بضرورة وضع سياسات وبرامج المسؤولية الاجتماعية التي تخدم القضايا التي تحل المشاكل الاجتماعية للمجتمع، وكذا تطبيق مبدأ الحوكمة من خلال الشفافية والإفصاح والعدالة، من أجل تحسين مؤشرات الأداء الخاصة بالمؤسسة الصناعية. الكلمات المفتاحية: الحوكمة، المسؤولية الاجتماعية، أداء المؤسسات الصناعية، مؤسسة "أن سي أ رويبة" الجزائر This study aims to identify the role played by governance and corporate social responsibility in improving the performance of the Algerian industrial establishments by presenting a case study of an Algerian industrial institution, NCA Ruweiba, which presented the various aspects of applying the standards and principles of corporate governance and responsibility In addition to some data obtained from the website of the Algerian Stock Exchange. The study concluded that governance and social responsibility play a major role in promoting investment To establish the business climate in an environment that is based on responsibility, control and commitment and to observe the principles of clarity and transparency in setting the strategic goals and plans of the company, to show the rights of its entities and their obligations and to manage its relationship with all stakeholders such as suppliers, financiers, consumers, regulators and others. Policies and programs of social responsibility that serve the issues that solve the social problems of society, as well as the application of the principle of governance through transparency, disclosure and justice, in order to improve performance indicators of the industrial institution. Key words: Governance, Social Responsibility, Performance of Industrial Establishments, NCA Ruwaiba Algeria.
Efficient and portable acceleration of quantum chemical many-body methods in mixed floating point precision using OpenACC compiler directives
Creators: name: Eriksen, Janus Juul
Publisher: name: arXiv
Year: 2016
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: It is demonstrated how the non-proprietary OpenACC standard of compiler directives may be used to compactly and efficiently accelerate the rate-determining steps of two of the most routinely applied many-body methods of electronic structure theory, namely the second-order Møller-Plesset (MP2) model in its resolution-of-the-identity (RI) approximated form and the (T) triples correction to the coupled cluster singles and doubles model (CCSD(T)). By means of compute directives as well as the use of optimized device math libraries, the operations involved in the energy kernels have been ported to graphics processing unit (GPU) accelerators, and the associated data transfers correspondingly optimized to such a degree that the final implementations (using either double and/or single precision arithmetics) are capable of scaling to as large systems as allowed for by the capacity of the host central processing unit (CPU) main memory. The performance of the hybrid CPU/GPU implementations is assessed through calculations on test systems of alanine amino acid chains using one-electron basis sets of increasing size (ranging from double- to pentuple-zeta quality). For all but the smallest problem sizes of the present study, the optimized accelerated codes (using a single multi-core CPU host node in conjunction with six GPUs) are found to be capable of reducing the total time-to-solution by at least an order of magnitude over optimized, OpenMP-threaded CPU-only reference implementations.
description: 38 pages, 1 table, 6 figures
Assessment of Appropriateness of the Indirect Distribution Channel of Ethio Telecom
Creators: name: Tadesse, Nehmya
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2014

description: Despite its impressive revenue contribution, the indirect channel of Ethio Telecom is full of administrative problems. In this indirect channel distribution the company on the one hand employs local distributors which are required to sell within their respective zone/region territory only and on the other hand national distributors which are free to circulate the products anywhere in the country. The objective of this research is therefore to evaluate appropriateness of the current indirect channel of ethio telecom and recommend an optimal channel structure alternative. Accordingly, questionnaires were distributed to three channel stakeholders namely Ethio Telecom staffs, distributors and retailers. In a nutshell, performance of the indirect distribution channel based on the primary data is poor qualitatively. The major poor performance areas are pillar terms of the distribution agreement (such as door to door distribution, territory confined distribution of the products) are not implemented, and Channel stakeholders indicated that it is impossible and not feasible to control territory confined distribution of ET's products. It is impossible to avoid territory breach. Some retailers purchase ET products not from distributors in their territory which is a best prove of uncontrollability of the policy of territory limited distribution. Consequently, the researcher proposed/recommended alternative and optimal distribution channel design.The recommendation is that ethio telecom needs to waive the concept of territory limited distribution and employ few mega national distributors at upstream channel level parallel to the undifferentiated nature of Ethiopian market. The national distributors would organize themselves in 14 regional/zonal branch offices parallel to organizational structure of ethio telecom. Candidate distributors for this proposal are Ethiopian Postal Service Enterprise and Hidassie Telecom Share Company. These two candidate and strategic business partners of ethio telecom have more than one thousand five hundred sales outlets together throughout Ethiopia.
Cartan Connections and Integrable Vortex Equations
Creators: name: Ross, Calum
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We demonstrate that integrable abelian vortex equations on constant curvature Riemann surfaces can be reinterpreted as flat non-abelian Cartan connections. By lifting to three dimensional group manifolds we find higher dimensional analogues of vortices. These vortex configurations are also encoded in a Cartan connection. We give examples of different types of vortex that can be interpreted this way, and compare and contrast this Cartan representation of a vortex with the symmetric instanton representation.
description: 20 pages, 1 figure