Using Conjunctions and Adverbs for Author Verification

Abstract: Linguistics and stylistics have been investigated for author identification for quite a while, but recently, we have testified a impressive growth in the volume with which lawyers and courts have called upon the expertise of linguists in cases of disputed authorship. This motivates computer science researchers to look to the problem of author identification from a different perspective. In this work, we propose a stylometric feature set based on conjunctions and adverbs of the Portuguese language to address the problem of author identification. Two different approaches of classification were considered. The first one is called writer-independent and it reduces the pattern recognition problem to a single model and two classes, hence, makes it possible to build robust system even when few genuine samples per writer are available. The second one is called the personal model, or writer-dependent, which very often performs better but needs a bigger number of samples per writer. Experiments on a database composed of short articles from 30 different authors and Support Vector Machine (SVM) as classifier demonstrate that the proposed strategy can produced results comparable to the literature

Hemispheric asymmetry in the sunspot cycle as a nonextensive phenomenon

The appearance of dark sunspots over the solar photosphere is not considered to be symmetric between the northern and southern hemispheres. Among the different conclusions obtained by several authors, we can point out that the North-South asymmetry is a real and systematic phenomenon and is not due to random variability. In the present work, we selected the sunspot area data of a sample of 13 solar cycles divided by hemisphere extracted from the Marshall Space Flight Centre (MSFC) database to investigate the behavior of probability distributions using an out-of-equilibrium statistical model a.k.a non-extensive statistical mechanics. Based on this statistical framework, we obtained that the non-extensive entropic parameter $q$ has a semi-sinusoidal variation with a period of $\sim$22 year (Hale cycle). Among the most important results, we can highlight that the asymmetry index $q(A)$ revealed the dominance of the northern hemisphere against the southern one. Thus, we concluded that the parameter $q(A)$ can be considered an effective measure for diagnosing long-term variations of the solar dynamo. Finally, our study opens a new approach to investigating solar variability from the nonextensive perspective.Comment: 17 pages, 2 tables and 5 figures. Submitted to Solar Physic

Corretion Method of Phantom Images and Classification of their Structures of Interest

O controle de câncer de mama representa um dos grandes desafios que os serviços de \ud saúde pública enfrentam atualmente. Para realizar o controle de qualidade de sistemas \ud mamográficos o Ministério da Saúde exige o uso de simuladores radiográficos (phantoms) \ud de mama. Com o objetivo de reduzir a subjetividade na avaliação das imagens de phantom\ud pela inspeção visual humana, está sendo desenvolvido um sistema computadorizado que \ud utiliza um método de correção em imagens digitalizadas, associado à classificação de suas \ud estruturas de interesse pelo critério de visibilidade. Ao comparar os resultados da \ud classificação através do algoritmo J48 da ferramenta WEKA com e sem a correção das \ud imagens, essa técnica apresentou uma melhora significativa na eficácia para determinadas \ud estruturas do phantom.Breast cancer control represents one of the greatest challenges that public health service \ud faces nowadays. To execute the quality control of mammographic systems, the Brazilian \ud Health Ministry demands the use of breast phantoms. Aiming to reduce the subjectivity \ud present in the evaluation of phantomimages through human visual inspection, a \ud computerised system has been developed that uses a correction method in its digitised \ud images, associated with the classification of its structures of interest by the visibility \ud criterion. Comparing the results of the classification using the J48 algorithm of the WEKA \ud package with and without image correction, this method presented a significant \ud improvement in the effectiveness for determining structures of the phantomCNPqCAPE

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum