Experiences in Automatic Keywording of Particle Physics Literature

Attributing keywords can assist in the classification and retrieval of documents in the particle physics literature. As information services face a future with less available manpower and more and more documents being written, the possibility of keyword attribution being assisted by automatic classification software is explored. A project being carried out at CERN (the European Laboratory for Particle Physics) for the development and integration of automatic keywording is described

Environmental bias and elastic curves on surfaces

The behavior of an elastic curve bound to a surface will reflect the geometry of its environment. This may occur in an obvious way: the curve may deform freely along directions tangent to the surface, but not along the surface normal. However, even if the energy itself is symmetric in the curve's geodesic and normal curvatures, which control these modes, very distinct roles are played by the two. If the elastic curve binds preferentially on one side, or is itself assembled on the surface, not only would one expect the bending moduli associated with the two modes to differ, binding along specific directions, reflected in spontaneous values of these curvatures, may be favored. The shape equations describing the equilibrium states of a surface curve described by an elastic energy accommodating environmental factors will be identified by adapting the method of Lagrange multipliers to the Darboux frame associated with the curve. The forces transmitted to the surface along the surface normal will be determined. Features associated with a number of different energies, both of physical relevance and of mathematical interest, are described. The conservation laws associated with trajectories on surface geometries exhibiting continuous symmetries are also examined.Comment: 30 pages, 3 figure

Isometric bending requires local constraints on free edges

While the shape equations describing the equilibrium of an unstretchable thin sheet that is free to bend are known, the boundary conditions that supplement these equations on free edges have remained elusive. Intuitively, unstretchability is captured by a constraint on the metric within the bulk. Naively one would then guess that this constraint is enough to ensure that the deformations determining the boundary conditions on these edges respect the isometry constraint. If matters were this simple, unfortunately, it would imply unbalanced torques (as well as forces) along the edge unless manifestly unphysical constraints are met by the boundary geometry. In this paper we identify the source of the problem: not only the local arc-length but also the geodesic curvature need to be constrained explicitly on all free edges. We derive the boundary conditions which follow. Contrary to conventional wisdom, there is no need to introduce boundary layers. This framework is applied to isolated conical defects, both with deficit as well, but more briefly, as surplus angles. Using these boundary conditions, we show that the lateral tension within a circular cone of fixed radius is equal but opposite to the radial compression, and independent of the deficit angle itself. We proceed to examine the effect of an oblique outer edge on this cone perturbatively demonstrating that both the correction to the geometry as well as the stress distribution in the cone kicks in at second order in the eccentricity of the edge.Comment: 25 pages, 3 figure

Confining spheres within hyperspheres

The bending energy of any freely deformable closed surface is quadratic in its curvature. In the absence of constraints, it will be minimized when the surface adopts the form of a round sphere. If the surface is confined within a hypersurface of smaller size, however, this spherical state becomes inaccessible. A framework is introduced to describe the equilibrium states of the confined surface. It is applied to a two-dimensional surface confined within a three-dimensional hypersphere of smaller radius. If the excess surface area is small, the equilibrium states are represented by harmonic deformations of a two-sphere: the ground state is described by a quadrupole; all higher multipoles are shown to be unstable.Comment: 18 pages, 3 figure

Programas de entrenamiento de memoria. Método U.M.A.M.

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A 10-way power divider based on a transducer and a radial junction operating in the circular TM01 mode

This work presents a 10-way Ku-band power divider using a mode transducer and a radial junction connected by an overmoded circular waveguide operating in the TM 01 mode. The circular symmetry of this mode has been exploited to obtain a power divider with the rectangular output ports radially distributed along the broad wall of the waveguides in H-plane configuration. This topology provides the same amplitude and phase for all the output ports. At the same time, a compact profile has been obtained, introducing a simple manufacturing for the two components of the divider. The first component is a mode transducer converting the TE 10 mode in the rectangular waveguide to the TM 01 mode in the circular waveguide. It is based on a novel topology providing a very high purity in the mode conversion with an attenuation for the other propagating mode, the TE 11c , higher than 60 dB. The second component is a 10-way radial junction that must work under the excitation of the TM 01 , whose special features, since this mode is not the fundamental one of the circular waveguide, will be highlighted. The final design has been validated with an experimental prototype, proposing a manufacturing based on four simple parts. This has been the key to obtain an experimental prototype with specifications in the state-of-the-art. The measured efficiency is better than 96.5% in a 16.7% relative frequency bandwidth from 11 GHz to 13 GHz, with return losses better than 25 dB in the common port. The measured difference between the signals at the output ports of the prototype is ±0.3 dB for the amplitudes and ±0.45° for the phases. A comparison of the obtained results with another divider based on the TE 01 mode shows the potential of the presented design for becoming an alternative to the more extended TE 01 -based power dividersThis work was supported by the Spanish Government through the Agencia Estatal de Investigacion, Fondo Europeo de Desarrollo Regional (AEI/FEDER, UE), under Grant TEC2016-76070-C3-1/2-R (ADDMATE

Toward conceptual indexing using automatic assignment of descriptors

Indexing techniques have reached a well maturated state. Digital libraries and other digital collections make an intense use of these algorithms to store and retrieve documents. In the other side, we have browsing techniques, which lets the user to gather the information. Current approaches are not yet advanced enough in order to satisfy the user. At CERN we are working in a indexer based on thesaurus descriptors. With a collection of documents related to thesaurus, user can manipulate them in a more conceptual way. Here we describe the core of this system, the automatic descriptor assigner