912 research outputs found
The CorDis Corpus Mark-up and Related Issues
CorDis is a large, XML, TEI-conformant, POS-tagged, multimodal, multigenre corpus representing a significant portion of the political and media discourse on the 2003 Iraqi conflict. It was generated from different sub-corpora which had been assembled by various research groups, ranging from official transcripts of Parliamentary sessions, both in the US and the UK, to the transcripts of the Hutton Inquiry, from American and British newspaper coverage of the conflict to White House press briefings and to transcriptions of American and British TV news programmes. The heterogeneity of the data, the specificity of the genres and the diverse discourse analytical purposes of different groups had led to a wide range of coding strategies being employed to make textual and meta-textual information retrievable.
The main purpose of this paper is to show the process of harmonisation and integration whereby a loose collection of texts has become a stable architecture. The TEI proved a valid instrument to achieve standardisation of mark-up. The guidelines provide for a hierarchical organisation which gives the corpus a sound structure favouring replicability and enhancing the reliability of research. In discussing some examples of the problems encountered in the annotation, we will deal with issues like consistency and re-usability, and will examine the constraints imposed on data handling by specific research objectives. Examples include the choice to code the same speakers in different ways depending on the various (institutional) roles they may assume throughout the corpus, the distinction between quotations of spoken or written discourse and quotations read aloud in the course of a spoken text, and the segmentation of portions of news according to participants interaction and use of camera/voiceover
Trivariate polynomial approximation on Lissajous curves
We study Lissajous curves in the 3-cube, that generate algebraic cubature
formulas on a special family of rank-1 Chebyshev lattices. These formulas are
used to construct trivariate hyperinterpolation polynomials via a single 1-d
Fast Chebyshev Transform (by the Chebfun package), and to compute discrete
extremal sets of Fekete and Leja type for trivariate polynomial interpolation.
Applications could arise in the framework of Lissajous sampling for MPI
(Magnetic Particle Imaging)
Regularity of sets with constant intrinsic normal in a class of Carnot groups
In this Note, we define a class of stratified Lie groups of arbitrary step
(that are called ``groups of type '' throughout the paper), and we prove
that, in these groups, sets with constant intrinsic normal are vertical
halfspaces. As a consequence, the reduced boundary of a set of finite intrinsic
perimeter in a group of type is rectifiable in the intrinsic sense (De
Giorgi's rectifiability theorem). This result extends the previous one proved
by Franchi, Serapioni & Serra Cassano in step 2 groups.Comment: Revised version: changed title and improved the presentation of the
paper. It will appear at Annales de l'Institut Fourie
Estudo de mosquitos antropofílicos (Diptera: Culicidae) em áreas de uma futura Unidade de Conservação, Itapema, SC, Brasil
TCC(graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Biológicas. Biologia.Foi realizado um levantamento faunístico de mosquitos (Diptera: Culicidae) antropofílicos diurnos em duas áreas de Mata Atlântica do sul do Brasil, onde será implantada uma Unidade de Conservação no município de Itapema, SC. Foram coletados 308 exemplares de 14 espécies, sendo que Ochlerotatus fluviatilis foi relatada pela primeira vez no leste de Santa Catarina. Numa das áreas, de Floresta Ombrófila Densa ainda bem preservada, a espécie predominante foi Anopheles cruzii. Na outra área de floresta, a qual apresenta maiores impactos por decorrência de atividades humanas, a espécie mais abundante foi Ochlerotatus scapularis. Foram relatadas, no total, quatro espécies de culicídeos que são vetores de doenças para os seres humanos
Bivariate Lagrange interpolation at the Padua points: the ideal theory approach
Padua points is a family of points on the square given by explicit
formulas that admits unique Lagrange interpolation by bivariate polynomials.
The interpolation polynomials and cubature formulas based on the Padua points
are studied from an ideal theoretic point of view, which leads to the discovery
of a compact formula for the interpolation polynomials. The convergence
of the interpolation polynomials is also studied.Comment: 11 page
Polynomial Meshes: Computation and Approximation
We present the software package WAM, written in Matlab, that generates Weakly
Admissible Meshes and Discrete Extremal Sets of Fekete and Leja type, for 2d and 3d
polynomial least squares and interpolation on compact sets with various geometries.
Possible applications range from data fitting to high-order methods for PDEs
The first search for variable stars in the open cluster NGC 6253 and its surrounding field
This work presents the first high-precision variability survey in the field
of the intermediate-age, metal--rich open cluster NGC 6253. Clusters of this
type are benchmarks for stellar evolution models. Continuous photometric
monitoring of the cluster and its surrounding field was performed over a time
span of ten nights using the Wide Field Imager mounted at the ESO-MPI 2.2m
telescope. High-quality timeseries, each composed of about 800 datapoints, were
obtained for 250,000 stars using ISIS and DAOPHOT packages. Candidate members
were selected by using the colour-magnitude diagrams and
period-luminosity-colour relations. Membership probabilities based on the
proper motions were also used. The membership of all the variables discovered
within a radius of 8 arcmin from the centre is discussed by comparing the
incidence of the classes in the cluster direction and in the surrounding field.
We discovered 595 variables and we also characterized most of them providing
their variability classes, periods, and amplitudes. The sample is complete for
short periods: we classified 20 pulsating variables, 225 contact systems, 99
eclipsing systems (22 Beta Lyr type, 59 Beta Per type, 18 RS CVn type), and 77
rotational variables. The time-baseline hampered the precise characterization
of 173 variables with periods longer than 4-5 days. Moreover, we found a
cataclysmic system undergoing an outburst of about 2.5 mag. We propose a list
of 35 variable stars (8 contact systems, 2 eclipsing systems, 15 rotational
variables, 9 long-period variables and the cataclysmic variable) as probable
members of NGC 6253.Comment: Astronomy and Astrophysics, in press. Extended version with tables
and light curve
Harnack Inequality for the Schrödinger Problem Relative to Strongly Local Riemannian p-Homogeneous Forms with a Potential in the Kato Class
We define a notion of Kato class of measures relative to a Riemannian strongly local p-homogeneous Dirichlet form and we prove a Harnack inequality (on balls that are small enough) for the positive solutions to a Schrödinger-type problem relative to the form with a potential in the Kato class
An Optimal Shaped Sensor Array Derivation
In Structural Health Monitoring (SHM) applications, the Direction of Arrival (DoA) estimation of Guided Waves (GW) on sensor arrays is often used as a fundamental means to locate Acoustic Sources (AS) generated by damages growth or undesired impacts in thin-wall structures (e.g., plates or shells). In this paper, we consider the problem of designing the arrangement and shape of piezo-sensors in planar clusters in order to optimize the DoA estimation performance in noise-affected measurements. We assume that: (i) the wave propagation velocity is unknown, (ii) the DoA is estimated via the time delays of wavefronts between sensors, and (iii) the maximum value of the time delays is limited. The optimality criterion is derived basing on the Theory of Measurements. The sensor array design is so that the DoA variance is minimized in an average sense by exploiting the Calculus of Variations. In this way, considering a three-sensor cluster and a monitored angles sector of 90°, the optimal time delays–DoA relations are derived. A suitable re-shaping procedure is used to impose such relations and, at the same time, to induce the same spatial filtering effect between sensors so that the sensor acquired signals are equal except for a time-shift. In order to achieve the last aim, the sensors shape is realized by exploiting a technique called Error Diffusion, which is able to emulate piezo-load functions with continuously modulated values. In this way, the Shaped Sensors Optimal Cluster (SS-OC) is derived. A numerical assessment via Green’s functions simulations shows improved performance in DoA estimation by means of the SS-OC when compared to clusters realized with conventional piezo-disk transducers
Hydrogeomorphic processes and torrent control works on a large alluvial fan in the eastern Italian Alps
Abstract. Alluvial fans are often present at the outlet of small drainage basins in alpine valleys; their formation is due to sediment transport associated with flash floods and debris flows. Alluvial fans are preferred sites for human settlements and are frequently crossed by transport routes. In order to reduce the risk for economic activities located on or near the fan and prevent loss of lives due to floods and debris flows, torrent control works have been extensively carried out on many alpine alluvial fans. Hazard management on alluvial fans in alpine regions is dependent upon reliable procedures to evaluate variations in the frequency and severity of hydrogeomorphic processes and the long-term performance of the torrent training works. An integrated approach to the analysis of hydrogeomorphic processes and their interactions with torrent control works has been applied to a large alluvial fan in the southern Carnic Alps (northeastern Italy). Study methods encompass field observations, interpretation of aerial photographs, analysis of historical documents, and numerical modelling of debris flows. The overall performance of control works implemented in the early decades of 20th century was satisfactory, and a reduction of hazardous events was recognised from features observed in the field and in aerial photographs, as well as from the analysis of historical records. The 2-D simulation of debris flows confirms these findings, indicating that debris flow deposition would not affect urban areas or main roads, even in the case of a high-magnitude event. Present issues in the management of the studied alluvial fan are representative of situations frequently found in the European Alps and deal with the need for maintenance of the control structures and the pressures for land use changes aimed at the economic exploitation of the fan surface
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