cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Simulating feedback from nuclear clusters: the impact of multiple sources
Creators: name: Bourne, Martin A.
name: Power, Chris
Publisher: name: arXiv
Year: 2015
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Nuclear star clusters (NCs) are found to exist in the centres of many galaxies and appear to follow scaling relations similar to those of super-massive black holes. Previous analytical work has suggested that such relations are a consequence of feedback regulated growth. We explore this idea using high resolution hydrodynamical simulations, focusing on the validity of the simplifying assumptions made in analytical models. In particular, we investigate feedback emanating from multiple stellar sources rather than from a single source, as is usually assumed, and show that collisions betweens shells of gas swept up by feedback leads to momentum cancellation and the formation of high density clumps and filaments. This high density material is resistant both to expulsion from the galaxy potential and to disruption by feedback; if it falls back onto the NC, we expect the gas to be available for further star formation or for feeding a central black hole. We also note our results may have implications for the evolution of globular clusters and stellar clusters in high redshift dark matter halos.
description: 5 pages, 4 figures, accepted for publication in MNRAS Letters
Extension of Modularity Density for Overlapping Community Structure
Creators: name: Chen, Mingming
name: Kuzmin, Konstantin
name: Szymanski, Boleslaw K.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Social and Information Networks (cs.SI)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Modularity is widely used to effectively measure the strength of the disjoint community structure found by community detection algorithms. Although several overlapping extensions of modularity were proposed to measure the quality of overlapping community structure, there is lack of systematic comparison of different extensions. To fill this gap, we overview overlapping extensions of modularity to select the best. In addition, we extend the Modularity Density metric to enable its usage for overlapping communities. The experimental results on four real networks using overlapping extensions of modularity, overlapping modularity density, and six other community quality metrics show that the best results are obtained when the product of the belonging coefficients of two nodes is used as the belonging function. Moreover, our experiments indicate that overlapping modularity density is a better measure of the quality of overlapping community structure than other metrics considered.
description: 8 pages in Advances in Social Networks Analysis and Mining (ASONAM), 2014 IEEE/ACM International Conference on
Freely decaying turbulence in force-free electrodynamics
Creators: name: Zrake, Jonathan
name: East, William E.
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Freely decaying relativistic force-free turbulence is studied for the first time. We initiate the magnetic field at a short wavelength and simulate its relaxation toward equilibrium on two and three dimensional periodic domains, in both helical and non-helical settings. Force-free turbulent relaxation is found to exhibit an inverse cascade in all settings, and in 3D to have a magnetic energy spectrum consistent with the Kolmogorov $5/3$ power law. 3D relaxations also obey the Taylor hypothesis; they settle promptly into the lowest energy configuration allowed by conservation of the total magnetic helicity. But in 2D, the relaxed state is a force-free equilibrium whose energy greatly exceeds the Taylor minimum, and which contains persistent force-free current layers and isolated flux tubes. We explain this behavior in terms of additional topological invariants that exist only in two dimensions, namely the helicity enclosed within each level surface of the magnetic potential function. The speed and completeness of turbulent magnetic free energy discharge could help account for rapidly variable gamma-ray emission from the Crab Nebula, gamma-ray bursts, blazars, and radio galaxies.
description: Accepted to the ApJ
American libraries in wartime: the role of propaganda
Creators: name: Smith, Ashley M.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007
Subjects: World War,1914-1918--Propaganda
Propaganda,American
World War,1939-1945--Propaganda
World War,1914-1918--Libraries
Public libraries--United States--History--20th century
American Library Association--War Service

description: This paper examines several periods of military conflict in American history and how these periods had an effect on the spread of propaganda through public libraries. First, it investigates the events leading up to, and including, the First World War in the years from 1914 to 1918. Although America was only actively involved in the war for a short period of time, propaganda was at work in the years leading up to military involvement. The paper then looks at propaganda in the aftermath of the war and the period leading up to and including World War II, mainly the years 1941 to 1945. Propaganda was still in heavy use at this time, although librarians were more aware of its existence and effects. After this war ended, the United States became involved in the Cold War and propaganda was not as often discussed in library literature. This paper will briefly looks at how McCarthy, Korea, and Vietnam all played a role in refining librarians' views on propaganda through the middle of the century. The paper concludes with an examination of how the legacy of the twentieth-century has followed librarians into the 1990s and 2000s. Modern warfare coupled with the attacks on 9/11 brought propaganda into a new, high-tech arena, and librarians have had to learn to teach patrons to find and judge information on their own.
Spatial sampling and beamforming for spherical microphone arrays
Creators: name: Rafaely, Boaz
Publisher: name: arXiv
Year: 2023
Subjects: subject: Audio and Speech Processing (eess.AS)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Spherical microphone arrays have been recently studied for spatial sound recording, speech communication, and sound field analysis for room acoustics and noise control. Complementary theoretical studies presented progress in spatial sampling and beamforming methods. This paper reviews recent results in spatial sampling that facilitate a wide range of spherical array configurations, from a single rigid sphere to free positioning of microphones. The paper then presents an overview of beamforming methods recently presented for spherical arrays, from the widely used delay-and-sum and Dolph-Chebyshev, to the more advanced optimal methods, typically performed in the spherical harmonics domain.
Wer hat Interesse daran, Religion als Motor der Unruhen auszumachen?
Creators: name: Von Der Heyde, Eberhard
Publisher: name: Südasien
Year: 2022

description: Als in einer Stadt im Süden des indischen Bundesstaates Orissas Tausende wütender Menschen gegen die Kirchen und das christliche Grundstück marschierten, stellten sich Mitglieder der Gemeinde zum Schutz um die Kirche. Sie standen dort „voller Angst, mit zitternden Knien“, so berichten sie. Angesichts der anrückenden Menge fürchteten sie, dass es Tote und Verletzte geben würde. Und dann rief jemand aus der Demonstration heraus ihnen zu: Habt keine Angst, wir kennen euch ja! Das entschlossene Eingreifen der Polizei hat dann den Tod vieler Menschen verhindern können. Diese beiden Ereignisse bestimmen die Erinnerung der Gemeinde an diesen Tag.
description: Südasien, Bd. 28/29 Nr. 4/1 2008/2009(2008): Menschenrechte in Südasien
Coulomb fields as perturbations of type D vacuum space-times
Creators: name: Düztaş, Koray
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We consider a test, non-null electromagnetic field special in the sense that the principal null directions of the field lie along the two repeated principal null directions of the type D vacuum background. We prove that the special non-null field is a valid solution of the Maxwell equations on a type D background. This field behaves as $1/r^2$ and the only non-vanishing Maxwell scalar is $ϕ_1$ so it can be called the Coulomb field. We show that the contribution to the energy and angular momentum fluxes of the Coulomb field vanishes at any surface of integration, on the type D vacuum backgrounds Kerr, Kerr-Taub-NUT, Taub-NUT, and Schwarzschild. Therefore this field does not lead to any perturbations of the mass and angular momentum parameters of these space-times.
description: More detailed than the published version
größte Scheindemokratie der Welt?
Creators: name: Hartig, Sebastian
name: Claus, Martina
Publisher: name: Südasien
Year: 2022

description: Die Hoffnung auf eine effizientere Menschenrechtsarbeit der Vereinten Nationen verbindet sich mit der universellen Überprüfung aller UN-Mitgliedstaaten; die Universal Periodic Review (UPR). In diesem Rahmen hatte sich auch Indien (gewähltes Mitglied des Menschenrechtsrates) am 10. April 2008 dem Verfahren zu unterziehen.
description: Südasien, Bd. 28/29 Nr. 4/1 2008/2009(2008): Menschenrechte in Südasien
Force-induced dispersion in heterogeneous media
Creators: name: Guérin, Thomas
name: Dean, David S
Publisher: name: arXiv
Year: 2015
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The effect of a constant applied external force, induced for instance by an electric or gravitational field, on the dispersion of Brownian particles in periodic media with spatially varying diffusivity, and thus mobility, is studied. We show that external forces can greatly enhance dispersion in the direction of the applied force and also modify, to a lesser extent and in some cases non-monotonically, dispersion perpendicular to the applied force. Our results thus open up the intriguing possibility of modulating the dispersive properties of heterogeneous media by using externally applied force fields. These results are obtained via a Kubo formula which can be applied to any periodic advection diffusion system in any spatial dimension.
description: Main text (4 pages, 2 figures) + Supplemental Material (4 pages)
Is Citation Analysis Worth It: A Comparison of the Usefulness of Local Citation Analysis, Interlibrary Loan Records and Usage Statistics for Collection Development Purposes in a Special Library
Creators: name: Loree, S.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007
Subjects: Library use studies--North Carolina
Interlibrary loans--Periodicals
Collection development(Libraries)--Periodicals
Interlibrary loans--United States--Evaluation
Government libraries--United States--Statistics--Periodicals
Special libraries--United States--Statistics--Periodicals

description: This study evaluates local citation analysis in comparison to interlibrary loan records and usage statistics as indicators for collection evaluation and development purposes in a special library setting as evidenced through a case study at the Environmental Protection Agency's Main Library in Research Triangle Park, North Carolina. More specifically, it examines how data gathered from these three tools compare as predictors for future trends in use of journals and as tools for developing parameters and guidelines for anticipatory collection development decisions in a scientific research library. Ultimately, citation analysis is the most successful in predicting the following year's usage.
Whole Slide Multiple Instance Learning for Predicting Axillary Lymph Node Metastasis
Creators: name: Shkëmbi, Glejdis
name: Müller, Johanna P.
name: Li, Zhe
name: Breininger, Katharina
name: Schüffler, Peter
name: Kainz, Bernhard
Publisher: name: arXiv
Year: 2023
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Breast cancer is a major concern for women's health globally, with axillary lymph node (ALN) metastasis identification being critical for prognosis evaluation and treatment guidance. This paper presents a deep learning (DL) classification pipeline for quantifying clinical information from digital core-needle biopsy (CNB) images, with one step less than existing methods. A publicly available dataset of 1058 patients was used to evaluate the performance of different baseline state-of-the-art (SOTA) DL models in classifying ALN metastatic status based on CNB images. An extensive ablation study of various data augmentation techniques was also conducted. Finally, the manual tumor segmentation and annotation step performed by the pathologists was assessed.
description: Accepted for MICCAI DEMI Workshop 2023
Zones of quiet in a broadband diffuse sound field
Creators: name: Rafaely, Boaz
Publisher: name: arXiv
Year: 2023
Subjects: subject: Audio and Speech Processing (eess.AS)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The zones of quiet in pure-tone diffuse sound fields have been studied extensively in the past, both theoretically and experimentally, with the well known result of the 10\,dB attenuation extending to about a tenth of a wavelength. Recent results on the spatial-temporal correlation of broadband diffuse sound fields are used in this study to develop a theoretical framework for predicting the extension of the zones of quiet in broadband diffuse sound fields. This can be used to study the acoustic limitations imposed on local active sound control systems such as an active headrest when controlling broadband noise. Spatial-temporal correlation is first revised, after which derivations of the diffuse field zones of quiet in the near-field and the far-field of the secondary source are presented. The theoretical analysis is supported by simulation examples comparing the zones of quiet for diffuse fields excited by tonal and broadband signals. It is shown that as a first approximation the zone of quiet of a low-pass filtered noise is comparable to that of a pure-tone with a frequency equal to the center frequency of the broadband noise bandwidth.
Iterative usability testing of a corporate Intranet
Creators: name: Fowler, Beth
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2001
Subjects: World Wide Web
Web sites--Evaluation
User-interfaces--Testing
Intranets

description: This paper details an effort to apply usability techniques to the redesign of a corporate intranet. The process included interviews, a heuristic review and three rounds of user testing. The goal of the project was to determine whether user performance and attitude improved across the three tests, and, if so, to suggest design principles which might account for this improvement. Intranets have become an important part of the business infrastructure for many companies. While they are often used to deliver organizational information, some intranets have evolved to become an integral part of the company's actual business processes and task workflow. Intranets have a tendency to grow through accretion rather than design, however, and as more of a company's information resources are added, the intranet can outgrow its ability to make the information easily available. User testing of the site can help developers design an intranet that is efficient and easy to use.
Tage des Terrors in Mumbai
Creators: name: Basting, Bernd
Publisher: name: Südasien
Year: 2022

description: Der Tod von fast 200 Menschen im November/Dezember 2008 in Mumbai – er kommt vom Meer. Abends im Dunkeln, gegen 9 Uhr, in Gestalt von zehn jungen Männern. Vielleicht stammen sie aus Pakistan; vor der Küste Gujarats haben sie offenbar gewaltsam Boote gekapert und landen an dem historischen Tor nach Indien: dem Gateway of India. 1911 ist König George V. dort hindurchgeschritten, 1915 Mahatma Gandhi (aus Südafrika kommend), Ende der Neunziger Salman Rushdie (nach vielen Jahren iranisch-islamistisch erzwungenen Zwangs-Exils in London); und nun: Akteure des Terrors, muslimische Extremisten, höchst gewaltbereit, mit Bomben, Granaten, Munition, Pistolen, AK-47-Schnellfeuergewehren. Am Colaba Causeway trennen sie sich in mehrere kleine Gruppen, die zu ihren Attentatszielen ausschwärmen: Die Luxushotels Taj Mahal Palace und Trident Oberoi, das Geschäftsviertel Nariman, mit dem jüdischen Gemeindezentrum Nariman House, der Hauptbahnhof Chatrapati Shivaji Terminus (Victoria Station), ein Krankenhaus und das bei Touristen wie indischen jungen Leuten beliebte Leopold’s Cafe.
description: Südasien, Bd. 28/29 Nr. 4/1 2008/2009(2008): Menschenrechte in Südasien
A Collection Analysis of the Ticknor and Fields Collection of the Rare Book Collection at the University of North Carolina at Chapel Hill
Creators: name: Leach, Ronald L.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2004
Subjects: Collection Development--College and University Libraries Rare Books
Ticknor & Fields
Publishers and Publishing--History

description: This study is an analysis of the Rare Book Collection's holdings and desiderata list for the Ticknor and Fields' collection and historical overview of the Ticknor and Fields publishing house. The purpose of this collection analysis is to assist the curator in collection development, to serve as a guide to researchers using the collection, and to assist librarians and catalogers who will continue to describe, catalog, and arrange the collection. This study is limited primarily to publications issued by Ticknor and Fields during the period of 1849 to 1853. The paper contains information on methodology and results and findings. It contains an overview of high spots of the collection and list of desirable first editions and selected later editions of items not currently in the Ticknor and Fields collection of the Rare Book Collection.
Critical nonequilibrium relaxation in the Swendsen-Wang algorithm in the Berezinsky-Kosterlitz-Thouless and weak first-order phase transitions
Creators: name: Nonomura, Yoshihiko
name: Tomita, Yusuke
Publisher: name: arXiv
Year: 2015
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Recently we showed that the critical nonequilibrium relaxation in the Swendsen-Wang algorithm is widely described by the stretched-exponential relaxation of physical quantities in the Ising or Heisenberg models. Here we make a similar analysis in the Berezinsky-Kosterlitz-Thouless phase transition in the two-dimensional (2D) XY model and in the first-order phase transition in the 2D $q=5$ Potts model, and find that these phase transitions are described by the simple exponential relaxation and power-law relaxation of physical quantities, respectively. We compare the relaxation behaviors of these phase transitions with those of the second-order phase transition in the 3D and 4D XY models and in the 2D $q$-state Potts models for $2 \le q \le 4$, and show that the species of phase transitions can be clearly characterized by the present analysis. We also compare the size dependence of relaxation behaviors of the first-order phase transition in the 2D $q=5$ and $6$ Potts models, and propose a quantitative criterion on "weakness" of the first-order phase transition.
description: 4 pages, 6 figures, RevTeX 4
End-user training and subsequent online search behavior among scientific researchers at the National Institute of Environmental Health Sciences
Creators: name: Quigley, Jane
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 1999
Subjects: Diffusion of innovations
End-user searching--teaching
Surveys--end-user searching
Citation indexes
Bibliographic instruction

description: This study examines the characteristics and search behavior of scientific researchers who received training in searching the Web of Science database at the National Institute of Environmental Health Sciences. The scientists were asked to evaluate the usefulness of various methods of learning to search the database. Drawing on diffusion of innovation theory, the study explores attributes of the database as perceived by the end-users, in particular complexity, compatibility, and relative advantage. A correlation exists between perceived complexity and the amount of use of the database. As to the types of search performed, subject and keyword searches outweighed all other kinds of search in importance to these users.
Optimal model-based beamforming and independent steering for spherical loudspeaker arrays
Creators: name: Rafaely, Boaz
name: Khaykin, Dima
Publisher: name: arXiv
Year: 2023
Subjects: subject: Audio and Speech Processing (eess.AS)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Spherical loudspeaker arrays have been recently studied for directional sound radiation, where the compact arrangement of the loudspeaker units around a sphere facilitated the control of sound radiation in three-dimensional space. Directivity of sound radiation, or beamforming, was achieved by driving each loudspeaker unit independently, where the design of beamforming weights was typically achieved by numerical optimization with reference to a given desired beam pattern. This is in contrast to the methods already developed for microphone arrays in general and spherical microphone arrays in particular, where beamformer weights are designed to satisfy a wider range of objectives, related to directivity, robustness, and side-lobe level, for example. This paper presents the development of a physical-model-based, optimal beamforming framework for spherical loudspeaker arrays, similar to the framework already developed for spherical microphone arrays, facilitating efficient beamforming in the spherical harmonics domain, with independent steering. In particular, it is shown that from a beamforming perspective, the spherical loudspeaker array is similar to the spherical microphone array with microphones arranged around a rigid sphere. Experimental investigation validates the theoretical framework of beamformer design.
Systemic Risk Management in Financial Networks with Credit Default Swaps
Creators: name: Leduc, Matt V.
name: Poledna, Sebastian
name: Thurner, Stefan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Risk Management (q-fin.RM)
subject: FOS: Economics and business

description: We study insolvency cascades in an interbank system when banks are allowed to insure their loans with credit default swaps (CDS) sold by other banks. We show that, by properly shifting financial exposures from one institution to another, a CDS market can be designed to rewire the network of interbank exposures in a way that makes it more resilient to insolvency cascades. A regulator can use information about the topology of the interbank network to devise a systemic insurance surcharge that is added to the CDS spread. CDS contracts are thus effectively penalized according to how much they contribute to increasing systemic risk. CDS contracts that decrease systemic risk remain untaxed. We simulate this regulated CDS market using an agent-based model (CRISIS macro-financial model) and we demonstrate that it leads to an interbank system that is more resilient to insolvency cascades.
description: 21 pages, 9 figures
The Development of a Shared Metadata Standard for Use in Oral History Collections
Creators: name: Vos, Jaycie
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2013
Subjects: Metadata
Cataloging of oral history materials
Oral history

description: Oral history formally emerged as a field of study in 1948 and continues to expand
through the present. Oral histories are primary sources with a focus on audio recordings
of interviews, and many archives hold and provide public access to oral history
collections. Because they present unique characteristics as archival objects, archival
standards do not easily apply to oral history collections, and, despite the urges of those in
the field, there are no widely implemented up-to-date cataloging standards. Specifically,
there is a lack in metadata content standards, leaving each collection to its own practices
and procedures. The author analyzed content of existing documents to explore how
archivists and librarians use metadata and archival description to describe oral history
collections containing both analog and digital materials. The findings related to locally
implemented metadata standards were used to develop a metadata content standard that
can be applied to oral history collections broadly.
Information Behaviors of Ethical Hackers
Creators: name: Smith, Lester
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2016
Subjects: Information-seeking strategies
Cybercriminals
Hackers (Computing)

description: Ethical hackers emulate the processes of cyber-criminals in controlled settings in order to test the security posture of their clients. One common part of this process is testing the susceptibility to social engineering. This study explores the information seeking habits of Ethical Hackers during the reconnaissance phase of a social engineering attack in order to better understanding the strategies involved in cyber-crime. Eight ethical hackers with social engineering experience were interviewed using contextual inquiry. Participants were asked to walk through their process for gathering information in two-three social engineering scenarios as well as asked to describe the scenario they most often encounter. The study revealed a semi-structured, cyclic approach to information gathering that used many of the same tools as everyday life social search. The results of this study should help businesses and individuals better understand the risk of posting information in public forums.
On the Hamilton-Jacobi method in classical and quantum nonconservative systems
Creators: name: Dutra, A. de Souza
name: Correa, R. A. C.
name: Moraes, P. H. R. S.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Physics (quant-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we show how to complete some Hamilton-Jacobi solutions of linear, nonconservative classical oscillatory systems which appeared in the literature and we extend these complete solutions to the quantum mechanical case. In addition, we get the solution of the quantum Hamilton-Jacobi equation for an electric charge in an oscillating pulsing magnetic field. We also argue that for the case where a charged particle is under the action of an oscillating magnetic field, one can apply nuclear magnetic resonance techniques in order to find experimental results regarding this problem. We obtain all results analytically, showing that the quantum Hamilton-Jacobi formalism is a powerful tool to describe quantum mechanics.
No evidence for bulk velocity from type Ia supernovae
Creators: name: Huterer, Dragan
name: Shafer, Daniel L.
name: Schmidt, Fabian
Publisher: name: arXiv
Year: 2015
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We revisit the effect of peculiar velocities on low-redshift type Ia supernovae. Velocities introduce an additional guaranteed source of correlations between supernova magnitudes that should be considered in all analyses of nearby supernova samples but has largely been neglected in the past. Applying a likelihood analysis to the latest compilation of nearby supernovae, we find no evidence for the presence of these correlations, although, given the significant noise, the data is also consistent with the correlations predicted for the standard $Λ$CDM model. We then consider the dipolar component of the velocity correlations -- the frequently studied "bulk velocity" -- and explicitly demonstrate that including the velocity correlations in the data covariance matrix is crucial for drawing correct and unambiguous conclusions about the bulk flow. In particular, current supernova data is consistent with no excess bulk flow on top of what is expected in $Λ$CDM and effectively captured by the covariance. We further clarify the nature of the apparent bulk flow that is inferred when the velocity covariance is ignored. We show that a significant fraction of this quantity is expected to be noise bias due to uncertainties in supernova magnitudes and not any physical peculiar motion.
description: 20 pages, 4 figures; added references, one table, and clarifications in the text to match the published version
Racecar: Ratings and Content Employed to Calculate Accurate Recommendations
Creators: name: Hecht, Eliah
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2009
Subjects: Information storage & retrieval systems
Tags (Metadata)
Recommender systems (Information filtering)

description: Racecar is a recommender system for movies that combines collaborative filtering-based,
feature-based, and tag-based recommendations. A simple linear model (SlopeOne) is used
for the collaborative filtering module, while the other two sub-systems are naive Bayes classifiers.
In order to derive the best system, the modules are tested both alone and in combination.
The lowest error (MAE 0.9328, RMSE 1.214) results from putting 90% weight on the collaborative
filtering module and 10% weight on the feature-based recommendation module.
The Problem of Moments: A Bunch of Classical Results With Some Novelties
Creators: name: Inverardi, Pier Luigi Novi
name: Tagliani, Aldo
name: Stoyanov, Jordan M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 44A60, 60E05, 62E10

description: We summarize significant classical results on (in)determinacy of measures in terms of their finite positive integer order moments. Well-known is the role of the smallest eigenvalues of Hankel matrices, starting from Hamburger's results a century ago and ending with the great progress made only in recent times by C. Berg and collaborators. We describe here known results containing necessary and sufficient conditions for moment (in)determinacy in both Hamburger and Stieltjes moment problems. In our exposition we follow an approach different from that commonly used. There are novelties well complementing the existing theory. Among them are: (a) to emphasize on the geometric interpretation of the indeterminacy conditions; (b) exploit fine properties of the eigenvalues of perturbed symmetric matrices allowing to derive new lower bounds for the smallest eigenvalues of Hankel matrices; these bounds are used for concluding indeterminacy; (c) provide new arguments to confirm classical results; (d) give new numerical illustrations involving commonly used probability distributions.
description: 23 pages, 5 figures. This version corrects 1 typo and 2 inaccuracies
Semi-discrete isothermic surfaces
Creators: name: Burstall, F.
name: Hertrich-Jeromin, U.
name: Mueller, C.
name: Rossman, W.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53A10, 53C42, 53A30, 37K25, 37K35

description: A Darboux transformation for polarized space curves is introduced and its properties are studied, in particular, Bianchi permutability. Semi-discrete isothermic surfaces are described as sequences of Darboux transforms of polarized curves in the conformal n-sphere and their transformation theory is studied. Semi-discrete surfaces of constant mean curvature are studied as an application of the transformation theory.
description: plain TeX, 12 pages
Detecting deviating data cells
Creators: name: Rousseeuw, Peter J.
name: Bossche, Wannes Van den
Publisher: name: arXiv
Year: 2016
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: A multivariate dataset consists of $n$ cases in $d$ dimensions, and is often stored in an $n$ by $d$ data matrix. It is well-known that real data may contain outliers. Depending on the situation, outliers may be (a) undesirable errors which can adversely affect the data analysis, or (b) valuable nuggets of unexpected information. In statistics and data analysis the word outlier usually refers to a row of the data matrix, and the methods to detect such outliers only work when at least half the rows are clean. But often many rows have a few contaminated cell values, which may not be visible by looking at each variable (column) separately. We propose the first method to detect deviating data cells in a multivariate sample which takes the correlations between the variables into account. It has no restriction on the number of clean rows, and can deal with high dimensions. Other advantages are that it provides estimates of the `expected' values of the outlying cells, while imputing missing values at the same time. We illustrate the method on several real data sets, where it uncovers more structure than found by purely columnwise methods or purely rowwise methods. The proposed method can help to diagnose why a certain row is outlying, e.g. in process control. It may also serve as an initial step for estimating multivariate location and scatter matrices.
description: To appear in Technometrics
Structural versus dynamical origins of mean-field behavior in a self-organized critical model of neuronal avalanches
Creators: name: Moosavi, S. Amin
name: Montakhab, Afshin
Publisher: name: arXiv
Year: 2015
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: Critical dynamics of cortical neurons have been intensively studied over the past decade. Neuronal avalanches provide the main experimental as well as theoretical tools to consider criticality in such systems. Experimental studies show that critical neuronal avalanches show mean-field behavior. There are structural as well as recently proposed [Phys. Rev. E 89, 052139 (2014)] dynamical mechanisms which can lead to mean-field behavior. In this work we consider a simple model of neuronal dynamics based on threshold self-organized critical models with synaptic noise. We investigate the role of high average connectivity, random long range connections, as well as synaptic noise in achieving mean-field behavior. We employ finite-size scaling in order to extract critical exponents with good accuracy. We conclude that relevant structural mechanisms responsible for mean-field behavior cannot be justified in realistic models of the cortex. However, strong dynamical noise, which can have realistic justifications, always leads to mean-field behavior regardless of the underlying structure. Our work provides a different (dynamical) origin than the conventionaly accepted (structural) mechanisms for mean-field behavior in neuronal avalanches.
description: 12 pages, 10 figures. To appear in Physical Review E
Bibliographie der Geschichte, Landes- und Volkskunde von Stadt und Kanton Zürich: 1. April 1972 bis 31. März 1973
Creators: name: Bühner, Carl
Publisher: name: Buchdruckerei a/d Sihl AG
Year: 1973
Subjects: subject: 010 Bibliografie
subject: Kanton Zürich
subject: Zürich
subject: Bibliografie
subject: Geschichte
subject: Landeskunde
subject: Volkskunde

description: Separatdruck aus dem Zürcher Taschenbuch auf das Jahr 1974.
Capturing Chronology and Extreme Values of Representative Days for Planning of Transmission Lines and Long-Term Energy Storage Systems
Creators: name: Moradi-Sepahvand, Mojtaba
name: Tindemans, Simon H.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The growing penetration of renewable energy sources (RESs) is inevitable to reach net zero emissions. In this regard, optimal planning and operation of power systems are becoming more critical due to the need for modeling the short-term variability of RES output power and load demand. Considering hourly time steps of one or more years to model the operational details in a long-term expansion planning scheme can lead to a practically unsolvable model. Therefore, a clustering-based hybrid time series aggregation algorithm is proposed in this paper to capture both extreme values and temporal dynamics of input data by some extracted representatives. The proposed method is examined in a complex co-planning model for transmission lines, wind power plants (WPPs), short-term battery and long-term pumped hydroelectric energy storage systems. The effectiveness of proposed mixed-integer linear programming (MILP) model is evaluated using a modified 6-bus Garver test system. The simulation results confirm the proposed model efficacy, especially in modeling long-term energy storage systems.
description: IEEE PowerTech 2023
Topological superfluids on a square optical lattice with non-Abelian gauge fields: Effects of next-nearest-neighbor hopping in the BCS-BEC evolution
Creators: name: Iskin, M.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We consider a two-component Fermi gas with attractive interactions on a square optical lattice, and study the interplay of Zeeman field, spin-orbit coupling and next-nearest-neighbor hopping on the ground-state phase diagrams in the entire BCS-BEC evolution. In particular, we first classify and distinguish all possible superfluid phases by the momentum-space topology of their zero-energy quasiparticle/quasihole excitations, and then numerically establish a plethora of quantum phase transitions in between. These transitions are further signalled and evidenced by the changes in the corresponding topological invariant of the system, \textit{i.e.}, its Chern number. Lastly, we find that the superfluid phase exhibits a reentrant structure, separated by a fingering normal phase, the origin of which is traced back to the changes in the single-particle density of states.
description: 12 pages with 5 figures
Libraries in the Houses of History: A Possible Model for House Museum Library Collections
Creators: name: Lazan, Betsy R.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2001
Subjects: Historical libraries--Collections
Historic house museums--Libraries
Museum libraries--Special collection
Local history--Special libraries

description: Generally, the nature of the house museum as both a public institution as well as a historic structure that requires special maintenance with attention to historical accuracy implies a special library with resources particularly suited to those needs. This paper considers those restoration, preservation and conservation information needs, as well as needs for information on interpretation, the subject area of the museum, house museum management, and other aspects of running this particular type of museum. This paper formulates a model for a historic house museum's library collection from a library literature perspective, based upon current printed and electronic resources on the subject as well as taking into account certain aspects and situations unique to house museums and their libraries. The paper proposes a method of structuring and classifying the collection in addition to suggesting the development for such a collection and its general categories.
A Free Boundary Problem for the Parabolic Poisson Kernel
Creators: name: Engelstein, Max
Publisher: name: arXiv
Year: 2015
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35R35

description: We study parabolic chord arc domains, introduced by Hofmann, Lewis and Nyström, and prove a free boundary regularity result below the continuous threshold. More precisely, we show that a Reifenberg flat, parabolic chord arc domain whose Poisson kernel has logarithm in VMO must in fact be a vanishing chord arc domain (i.e. satisfies a vanishing Carleson measure condition). This generalizes, to the parabolic setting, a result of Kenig and Toro and answers in the affirmative a question left open in the aforementioned paper of Hofmann et al. A key step in this proof is a classification of "flat" blowups for the parabolic problem.
description: 91 pages. Comments welcome
title: Frobenius structures, Coxeter discriminants, and supersymmetric mechanics
Creators: name: Antoniou, Georgios
Publisher: name: University of Glasgow
Year: 2020
Subjects: subject: Frobenius structures, Coxeter discriminants, supersymmetric mechanics.

description: This thesis contains two directions both related to Frobenius manifolds. In the first part we deal with the orbit space $M_W = V/W$ of a finite Coxeter group $W$ acting in its reflection representation $V$. The orbit space $M_W$ carries the structure of a Frobenius manifold and admits a pencil of flat metrics of which the Saito flat metric $η$, defined as the Lie derivative of the $W$-invariant form $g$ on $V$ is the key object. In the main result of the first part we find the determinant of Saito metric restricted on the Coxeter discriminant strata in $M_W$ . It is shown that this determinant in the flat coordinates of the form $g$ is proportional to a product of linear factors. We also find multiplicities of these factors in terms of Coxeter geometry of the stratum. In the second part we study $N = 4$ supersymmetric extensions of quantum mechanical systems of Calogero–Moser type. We show that for any $∨$-system, in particular, for any Coxeter root system, the corresponding Hamiltonian can be extended to the supersymmetric Hamiltonian with $D(2,1;α)$ symmetry. We also obtain $N = 4$ supersymmetric extensions of Calogero–Moser–Sutherland systems. Thus, we construct supersymmetric Hamiltonians for the root systems $BC_N$, $F_4$ and $G_2$.
Fannish Librarians: The Intersection of Fandom and Library and Information Science
Creators: name: Koven-Matasy, Veronica
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2013
Subjects: Library school students
Library employees
Fan fiction

description: This study explored the connection between fandom and library and information science by means of a focus group and survey of individuals who are members of both fandom and the LIS community, in order to better understand the long-term effects of participating in fandom within this group. I hypothesized that participating in fandom will have in some cases provided an affinity space for LIS students and professionals to learn and practice skills usually associated with LIS professions. This proved to be true, but the most valuable aspect of fandom as suggested by the responses of study participants was social rather than skill-based.
A unified approach to electron and neutrino elastic scattering off nuclei with an application to the study of the axial structure
Creators: name: Moreno, O.
name: Donnelly, T. W.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We show a relationship between elastic electron scattering observables and the elastic neutrino cross section that provides a straightforward determination of the latter from experimental data of the former and relates their uncertainties. An illustration of this procedure is presented using a Hartree-Fock mean field for the nuclear structure of a set of even-even nuclear targets, using the spectra of the neutrinos produced in pion decay at rest. We also analyze the prospects to measure the incoherent axial contribution to the neutrino elastic scattering in odd targets.
GL(2,R)-Invariant Measures in Marked Strata: Generic Marked Points, Earle-Kra for Strata, and Illumination
Creators: name: Apisa, Paul
Publisher: name: arXiv
Year: 2016
Subjects: subject: Dynamical Systems (math.DS)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics

description: We classify GL(2,R) invariant point markings over components of strata of Abelian differentials. Such point markings exist only when the component is hyperelliptic and arise from marking Weierstrass points or two points exchanged by the hyperelliptic involution. We show that these point markings can be used to determine the holomorphic sections of the universal curve restricted to orbifold covers of subvarieties of the moduli space of Riemann surfaces that contain a Teichmuller disk. The finite blocking problem is also solved for translation surfaces with dense GL(2,R) orbit.
description: 30 pages
Analysis of remote reference correspondence at a Large Academic Manuscripts Collection
Creators: name: Martin, Kristin E.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2000
Subjects: Use studies--Manuscripts
Archives--Reference services--Deans Achievement Award--Best Masters Papers Awarded 2001
Electronic mail systems

description: This paper provides an analysis of the remote reference correspondence of the Southern Historical Collection and General and Literary Manuscripts (SHC)_ at the University of North Carolina at Chapel Hill, to observe the effects of providing online holdings information and the use of e-mail in reference correspondence.  The study examines 595 letter, phone, facsimile, and e-mail correspondence units sent to the SHC in 1995 and 1999.  Correspondence units are analyzed to determine the types of research performed, types of questions asked, and the responses of the Southern Historical Collection.  The study finds that the amount of remote correspondence increased dramatically between the two selected years, with e-mail becoming the preferred method of inquiry.  In 1999, more questions came from casual users researching for personal reasons and more users took advantage of online holdings information to shape their reference questions than in 1995.  The proportion of remote users visiting the SHC in person decreased between the two years, suggesting that more users now expect to perform research without visiting the collection.  Archivists must be prepared to accept new influxes of remote researchers and to find methods to improve remote reference services.
Compressive sensing based differential channel feedback for massive MIMO
Creators: name: Shen, Wenqian
name: Dai, Linglong
name: Shi, Yi
name: Zhu, Xudong
name: Wang, Zhaocheng
Publisher: name: arXiv
Year: 2015
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: Massive multiple-input multiple-output (MIMO) is becoming a key technology for future 5G wireless communications. Channel feedback for massive MIMO is challenging due to the substantially increased dimension of MIMO channel matrix. In this letter, we propose a compressive sensing (CS) based differential channel feedback scheme to reduce the feedback overhead. Specifically, the temporal correlation of time-varying channels is exploited to generate the differential channel impulse response (CIR) between two CIRs in neighboring time slots, which enjoys a much stronger sparsity than the original sparse CIRs. Thus, the base station can recover the differential CIR from the highly compressed differential CIR under the framework of CS theory. Simulations show that the proposed scheme reduces the feedback overhead by about 20\% compared with the direct CS-based scheme.