ANÁLISE DO PARADIGMA BITTORRENT PARA STREAMING DE VÍDEO SOB DEMANDA NA INTERNET ANTE ACESSO SEQUENCIAL PARTICIONADO SINCRONIZADO

Considering the video-on-demand (VoD) streaming serviceand a mostly sequential-data access pattern by users, thisarticle has the two following goals. Firstly, to analyze theBitTorrent paradigm's eciency under this access-patterntype. Secondly, to propose and analyze a new policy for dataselection by users, denoted as Smart Policy, focused on thisaccess-pattern type. For that, simulations are carried outin dierent VoD streaming scenarios, evaluating a varietyof performance metrics. Compared to previous proposalsin the literature, the nal results highlight optimizationsof up to 24,3% and 100% at the download rate and datawaiting time, respectively. Conclusions and directions forfuture work close this article.DOI: 10.36558/rsc.v11i2.722

Automatic detection of faults in race walking. A comparative analysis of machine-learning algorithms fed with inertial sensor data

The validity of results in race walking is often questioned due to subjective decisions in the detection of faults. This study aims to compare machine-learning algorithms fed with data gathered from inertial sensors placed on lower-limb segments to define the best-performing classifiers for the automatic detection of illegal steps. Eight race walkers were enrolled and linear accelerations and angular velocities related to pelvis, thighs, shanks, and feet were acquired by seven inertial sensors. The experimental protocol consisted of two repetitions of three laps of 250 m, one performed with regular race walking, one with loss-of-contact faults, and one with knee-bent faults. The performance of 108 classifiers was evaluated in terms of accuracy, recall, precision, F1-score, and goodness index. Generally, linear accelerations revealed themselves as more characteristic with respect to the angular velocities. Among classifiers, those based on the support vector machine (SVM) were the most accurate. In particular, the quadratic SVM fed with shank linear accelerations was the best-performing classifier, with an F1-score and a goodness index equal to 0.89 and 0.11, respectively. The results open the possibility of using a wearable device for automatic detection of faults in race walking competition

Arcabouço de arquitetura da informação para ciclo de vida de projeto de vocabulário controlado : uma aplicação em Engenharia de Software

Tese (doutorado)—Universidade de Brasília, Faculdade de Ciência da Informação, Programa de Pós-Graduação em Ciência da Informação, 2017.A pesquisa que resultou nesta tese investigou processos de desenvolvimento e de avaliação de vocabulários controlados. Esta tese inclui os seguintes elementos: resultado de pesquisa bibliográfica sobre arquitetura da informação, recuperação da informação, organização da informação e representação da informação; proposta de arcabouço para ciclo de vida de projeto de vocabulário controlado; e exemplo de uso de elementos desse arcabouço na construção de um protótipo de vocabulário controlado no domínio da Engenharia de Software. O arcabouço proposto é composto por arquitetura de referência, modelo de domínio, modelo de qualidade e lista de atividades. Entre os elementos do modelo de qualidade proposto, existe uma lista de características de qualidade de vocabulários controlados. Os modelos propostos estão parcialmente alinhados a ferramentas semânticas existentes.The research that resulted in this thesis has investigated development and evaluation processes of controlled vocabularies. This thesis includes the following elements: results of a bibliographic research on information architecture, information recovery, information organization and information representation; proposal of a framework for controlled vocabulary project life cycle; and example of use of this framework during the construction of a prototype of a controlled vocabulary on the Software Engineering domain. The proposed framework is composed of reference architecture, domain model, quality model and list of activities. Among the elements of the proposed quality model, there is a list of controlled vocabulary quality characteristics. The proposed models are partially aligned to existing semantic tools