253 research outputs found
Extraction from NP, frequency, and minimalist gradient harmonic grammar
Extraction of a PP from an NP in German is possible only if the headnoun and the governing verb together form a natural predicate. We show that thiscorresponds to collocational frequency of the verb-noun combinations incorpora, based on the metric of ΔP. From this we conclude that frequency shouldbe conceived of as a language-external grammatical building block that candirectly interact with language-internal grammatical building blocks (like trig-gers for movement and economy constraints blocking movement) in excitatoryand inhibitory ways. Integrating frequency directly into the syntax is not anoption in most current grammatical theories. However, things are different inGradient Harmonic Grammar, a version of Optimality Theory where linguistic objectsof various kinds can be assigned strength in the form of numerical values (weights).We show that by combining a Minimalist approach to syntactic derivations with aGradient Harmonic Grammar approach of constraint evaluation, the role of fre-quency in licensing extraction from PP in German can be integrated straightfor-wardly, the only additional prerequisite being that (verb-noun) dependencies qualifyas linguistic objects that can be assigned strength (based on their frequency)
Uniform existence of the integrated density of states for random Schr\"odinger operators on metric graphs over
We consider ergodic random magnetic Schr\"odinger operators on the metric
graph with random potentials and random boundary conditions
taking values in a finite set. We show that normalized finite volume eigenvalue
counting functions converge to a limit uniformly in the energy variable. This
limit, the integrated density of states, can be expressed by a closed
Shubin-Pastur type trace formula. It supports the spectrum and its points of
discontinuity are characterized by existence of compactly supported
eigenfunctions. Among other examples we discuss percolation models.Comment: 17 pages; typos removed, references updated, definition of subgraph
densities explaine
Lexibank, a public repository of standardized wordlists with computed phonological and lexical features
The past decades have seen substantial growth in digital data on the world’s languages. At the same time, the demand for cross-linguistic datasets has been increasing, as witnessed by numerous studies devoted to diverse questions on human prehistory, cultural evolution, and human cognition. Unfortunately, most published datasets lack standardization which makes their comparison difficult. Here, we present a new approach to increase the comparability of cross-linguistic lexical data. We have designed workflows for the computer-assisted lifting of datasets to Cross-Linguistic Data Formats, a collection of standards that make these datasets more Findable, Accessible, Interoperable, and Reusable (FAIR). We test the Lexibank workflow on 100 lexical datasets from which we derive an aggregated database of wordlists in unified phonetic transcriptions covering more than 2000 language varieties. We illustrate the benefits of our approach by showing how phonological and lexical features can be automatically inferred, complementing and expanding existing cross-linguistic datasets
Feed-Forward Chains of Recurrent Attractor Neural Networks Near Saturation
We perform a stationary state replica analysis for a layered network of Ising
spin neurons, with recurrent Hebbian interactions within each layer, in
combination with strictly feed-forward Hebbian interactions between successive
layers. This model interpolates between the fully recurrent and symmetric
attractor network studied by Amit el al, and the strictly feed-forward
attractor network studied by Domany et al. Due to the absence of detailed
balance, it is as yet solvable only in the zero temperature limit. The built-in
competition between two qualitatively different modes of operation,
feed-forward (ergodic within layers) versus recurrent (non- ergodic within
layers), is found to induce interesting phase transitions.Comment: 14 pages LaTex with 4 postscript figures submitted to J. Phys.
Thermal Density Functional Theory in Context
This chapter introduces thermal density functional theory, starting from the
ground-state theory and assuming a background in quantum mechanics and
statistical mechanics. We review the foundations of density functional theory
(DFT) by illustrating some of its key reformulations. The basics of DFT for
thermal ensembles are explained in this context, as are tools useful for
analysis and development of approximations. We close by discussing some key
ideas relating thermal DFT and the ground state. This review emphasizes thermal
DFT's strengths as a consistent and general framework.Comment: Submitted to Spring Verlag as chapter in "Computational Challenges in
Warm Dense Matter", F. Graziani et al. ed
TerrHum: an iPhone app for classifying forest humipedons.
The knowledge of a little number of specific terms is necessary to investigate and describe the forest topsoils: diagnostic components, diagnostic organic and organic-mineral horizons and the 17 series of humus horizons composing all the observed real forest not submerged topsoils. Diagnostic horizons are grouped in humus forms, which represent five humus systems. To become a good topsoil investigator is then only a question of field experience. No mean to do otherwise: you must go in the field with a blade and a good manual and put your hand in the soil. You have to make a hole and to observe on your knee a wall of the pit, from the top to the bottom, detecting all the characters that you find indicated in the manual. At the beginning you will be discouraged, things change from a site to another and never are exactly as in the manual. After few days of difficult survey, you will be able to know your soil even without doing a hole. Be patient and follow what it is indicated in the published first eight articles of Humusica (http://intra.tesaf.unipd.it/people/zanella/hmanual.html). On the poster, you find some examples of diagnostic properties of forest topsoils, and a dichotomy key of classification, you can copy paste and take with you in the field. An iPhone application (Terrhum) allows to bring in the field the necessary information for a fast classification of the topsoil
TerrHum: an iOS application for classifying terrestrial humipedons and some considerations about soil classification
International audienceThe name TerrHum is an abbreviation of the words “Terrestrial” (not hydromorphic, not submerged) and “Humipedon” (organic and organic-mineral humus horizons). With this application, it is possible to describe and classify terrestrial forest and grassland topsoils in a system published as a Special Issue entitled “Humusica 1– Terrestrial Natural Humipedons” in the journal Applied Soil Ecology. The iOS application TerrHum allows the storage of the main content of Humusica 1 on a cellular phone. Images, diagrams and simplified tables of classification may be recalled with a few touches on the screen. Humus forms, representing five humus systems, are classified based on the vertical arrangement of diagnostic horizons and their attributes. TerrHum allows accessing specific figures that are stored in a virtual cloud and can be downloaded the first time the user recalls them. Once all figures have been opened in the device, the application is ready to use, without any further internet connection. The application is in continuous evolution
Occupation numbers in density-functional calculations
It is the intention of this paper to rigorously clarify the role of the
occupation numbers in the current practical applications of the density
functional formalism. In these calculations one has to decide how to distribute
a given, fixed number of electrons over a set of single-particle orbitals. The
conventional choice is to have orbitals below the Fermi level completely
occupied and the orbitals above the Fermi level empty. Although there is a
certain confusion in literature why this choice is superior to any others, the
general belief is that it can justified by treating the occupation numbers as
variational parameters and then applying Janak's theorem or similar reasoning.
We demonstrate that there is a serious flaw in those arguments,mainly the
kinetic energy and therefore the exchange-correlation potential are not
differentiable with respect to density for arbitrary occupation numbers. It is
rigorously shown that in the present context of the density functional
calculations there is no freedom to vary the occupation numbers. The occupation
numbers cannot be considered as variational parameters.Comment: 10 pages, Revtex, accepted for publication by Phys.Rev.
Conceptual Design of a Liquid Helium Vertical Test-Stand for 2m long Superconducting Undulator Coils
Superconducting Undulators (SCUs) can produce higher photon flux and cover a wider photon energy range compared to permanent magnet undulators (PMUs) with the same vacuum gap and period length. To build the know-how to implement superconducting undulators for future upgrades of the European XFEL facility, the test stand SUNDAE1 for the characterization of SCU is being developed. The purpose of SUNDAE1 is the training, tuning and development of new SCU coils by means of precise magnetic field measurements. The experimental setup will allow the characterization of magnets up to 2m in length. These magnets will be immersed in a Helium bath at 4K or 2K temperature. In this article, we describe the experimental setup and highlight its expected performances
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