1,041 research outputs found

    Rating prediction on yelp academic dataset using paragraph vectors

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    This work studies the application of Paragraph Vectors to the Yelp Academic Dataset reviews in order to predict user ratings for different categories of businesses like auto repair, restaurants or veterinarians. Paragraph Vectors is a word embeddings techniques were each word or piece of text is converted to a continuous low dimensional space. Then, the opinion mining or sentiment analysis is observed as a classification task, where each user review is associated with a label the rating - and a probabilistic model is built with a logistic classifier. Following the intuition that the semantic information present in textual user reviews is generally more complex and complete than the numeric rating itself, this work applies Paragraph Vectors successfully toYelp dataset and evaluates its results.info:eu-repo/semantics/acceptedVersio

    Using chained machine learning models for scientific articles recommendation

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    Recommender systems are commonly used when it comes to online multimedia service providers or worldwide retail companies. Although, regarding educational resources, scientific papers and books, or other items with extensive textual content and description, recommendation systems are only in early development. In this paper, we propose a new approach entirely based on chained machine learning model store present and rank scientific papers. The first model a word embeddings model supported on a shallow neural network - is trained using a synthesized paper unit - a composition of the title, the abstract, the publishing conference or journal, and the year - that accurately captures paper’s semantic information. Later we train pairwise learning to a rank model based on a support vector machine (SVM) using relevant and irrelevant papers. We show that our approach achieves state-of-art results and does not rely on any language dependent or domain knowledge. It only uses available on-line data and proves to be efficient in either user-dependent and user independent modeling.info:eu-repo/semantics/acceptedVersio

    A blockchain and gamification approach for smart parking

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    City parking is increasingly complex and available parking spaces are scarce. Being able to identify a space to park their cars can lead many drivers to drive around the intended parking area several times, increasing traffic density and pollution. In this research we propose a collaborative blockchain solution with gamification for parking. Users collaborate to report free spaces and receive free parking minutes for their service to the community. In parallel, this approach can be used to collect beacon information from the parked vehicles and create a low-cost collaborative approach for managing a parking control process platform Blockchain that can handle this distributed process and the gamification platform increases users’ participation.info:eu-repo/semantics/acceptedVersio

    Neonatal septic arthritis – A challenging diagnosis

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    Introdução: O diagnóstico de artrite séptica no recém-nascido é difícil e requer alto grau de suspeição dado que nesta faixa etária a clínica é fruste. Caso clínico: Apresenta-se o caso de um recém-nascido a quem foi diagnosticada paralisia do plexo braquial direito aos 10 dias de vida. Aos 17 dias de vida por limitação da abdução da anca direita levantou-se a suspeita de displasia de desenvolvimento da anca. Foi efetuada ecografia, que corroborou o diagnóstico e o recém-nascido foi encaminhado para consulta de Ortopedia Pediátrica aos 20 dias de vida. Após estudo adequado, concluiu tratar-se de um caso de artrite séptica poliarticular. Atualmente aos oito anos de idade apresenta sequelas no membro superior direito com deformidade e encurtamento do mesmo. Discussão/conclusão: O atraso no diagnóstico e tratamento desta patologia acarreta sequelas futuras que podem ser irreversíveis. Os autores pretendem com a exposição deste caso alertar para a dificuldade e importância do diagnóstico precoce desta patologia

    Galhadores (Cecidomyiidae, Diptera) em Calophyllum brasiliense (Clusiaceae): descrições e biologia

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    Five new species of gall makers (Cecidomyiidae, Diptera) associated with Calophyllum brasiliense (Clusiaceae) are described and illustrated from Carapebus, State of Rio de Janeiro, Brazil : Lopesia caulinaris, L.conspicua, L. elliptica, L. linearis and Contarinia gemmae. Some biological and ecological data are given.Cinco espécies novas galhadoras (Cecidomyiidae, Diptera) associadas com Calophyllum brasiliense (Clusiaceae) são descritas e ilustradas de Carapebus, Estado do Rio de Janeiro, Brasil: Lopesia caulinaris, L. conspicua, L. elliptica, L. linearis and Contarinia gemmae. Algumas informações biológicas e ecológicas são fornecidas

    Synthesis and characterization of new injectable and degradable dextran-based hydrogels

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    Injectable and degradable hydrogels are very interesting networks for drug delivery and cell transplantation applications since they can be administered in the human body in a minimally invasive way. In most cases, the crosslinking reaction occurs by photopolymerisation or free radical polymerisation; however, the use of chemical initiators may promote cell death. In the current work, injectable and degradable dextran-based hydrogels were prepared without the use of initiators. Dextran, a natural glucose-containing polysaccharide, was oxidized with sodium periodate (dexOx) and the derivatives characterized by NMR and FTIR spectroscopy's as well as by colorimetric techniques. The oxidized derivatives were crosslinked with adipic acid dihydrazide (AAD), forming a gel within 2-4 min. The obtained hydrogels were characterized by their mechanical properties, swelling and degradation behavior under physiologic conditions. In addition, the hydrogel interior morphology as well as porous structure was evaluated by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). MIP analysis showed that dexOx hydrogels crosslinked with 10% of AAD were macroporous with pore sizes ranging from 0.32 to 0.08 [mu]m. As expected, the average pore size increased during hydrogel degradation as confirmed by SEM and MIP studies.http://www.sciencedirect.com/science/article/B6TXW-4GX64XT-3/1/4e9cbb2544094cda02e21f70e1abcc6

    A simple prescription for simulating and characterizing gravitational arcs

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    Simple models of gravitational arcs are crucial to simulate large samples of these objects with full control of the input parameters. These models also provide crude and automated estimates of the shape and structure of the arcs, which are necessary when trying to detect and characterize these objects on massive wide area imaging surveys. We here present and explore the ArcEllipse, a simple prescription to create objects with shape similar to gravitational arcs. We also present PaintArcs, which is a code that couples this geometrical form with a brightness distribution and adds the resulting object to images. Finally, we introduce ArcFitting, which is a tool that fits ArcEllipses to images of real gravitational arcs. We validate this fitting technique using simulated arcs and apply it to CFHTLS and HST images of tangential arcs around clusters of galaxies. Our simple ArcEllipse model for the arc, associated to a S\'ersic profile for the source, recovers the total signal in real images typically within 10%-30%. The ArcEllipse+S\'ersic models also automatically recover visual estimates of length-to-width ratios of real arcs. Residual maps between data and model images reveal the incidence of arc substructure. They may thus be used as a diagnostic for arcs formed by the merging of multiple images. The incidence of these substructures is the main factor preventing ArcEllipse models from accurately describing real lensed systems.Comment: 12 pages, 11 figures, accepted for publication in A&

    EXPERIMENTAL ANALYSIS OF A HYBRID DRYER

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    Artificial dryers promote a high-quality food drying, in spite of the considerable energy consumption. Solar dryers use only solar energy to heat the drying airflow; nevertheless, it is not possible to control the airflow thermal conditions. Hybrid solar dryers arise as an interesting option to reduce the drying costs (compared to the artificial dryer’s costs). Hybrid solar dryers improve the quality of the final product due to the control of the thermal drying condition. This paper presents an experimental analysis of an innovative hybrid solar-electrical dryer. This dryer consists of two chambers: solar chamber and drying chamber with electrical air heater. An experimental evaluation of the airflow in the device was performed and the average values of the temperature and the mass flow were presented as a function of the ambient conditions. To determine the performance of the proposed dryer, banana slices were dried in the device and the results were compared with natural sun drying and artificial drying

    Motion control of mobile autonomous robots using non-linear dynamical systems approach

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    This paper presents a solution to the problem of motion control of an autonomous robot, moving in a dynamical and unstable environment. It is based on non-linear dynamical systems, modelling the state variables that define the motion of a robot under an omnidirectional platform, like its direction of navigation and velocity. The approach used, is based on a set of non-linear differential equations that model the evolution of state variables along time, based on the concept of attractors and repellers. In the official RoboCup Middle Size League field, a target is used to attract the robot to a certain position (could be the ball or a desired position to receive the ball), while a repeller could move the robot away from its original path (given by obstacles in the surrounding environment). The research was firstly carried out in a computational simulation environment and later on with robots in a real environmentThis work was developed at the Automation and Robotics Laboratory by MINHO R&D TEAM, University of Minho, under the supervision of Professor A. Fernando Ribeiro and A. Gil Lopes. The knowledge exchanging between the RoboCup’s MSL teams and community contributed greatly for the development of this work. This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio
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