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Publicações

2019

Proposal of a low cost high performance educational mobile robot: An RPI and Arduino approach

Autores
Gonçalves, J; Pinto, AF; Pinto, VH; Costa, P;

Publicação
Robotics Transforming the Future - Proceedings of the 21st International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2018

Abstract
In this paper the proposal of a low cost high performance educational mobile robot is described. The robot is based on an Arduino, applied in the low level control, while the high level control loop is carried out by an RPI running an object pascal application. The described robot was prototyped in order to have a competitive participation in the Robotic Day Line Follower 2017 competition, taking advantage of the RPI capabilities. The RPI allows the use of higher performance sensors, when compared with the most common standard approaches based on a single 8 bit RISC micro-controller, having as disadvantage the inevitable robot size increase, which compromises in certain situations the robot maneuverability and increases the power consumption. The robot is equipped with DC Motors, the chosen line follower sensor is the picamera and for the obstacle detection sonar sensors are used. © CLAWAR Association.

2019

Is it a lay or medico-scientific concept? Automatic classification in two languages

Autores
Santos, PM; Lopes, CT;

Publicação
2019 14TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI)

Abstract
Searching for health information is the third most popular activity on the Internet. There is evidence that query suggestions in lay and medico-scientific terminology improve health information retrieval by who is not a health professional. Developing systems that suggest queries in these terminologies requires knowing if concepts are lay or medico-scientific. In this paper, we propose and compare approaches to compute the degree of association of a concept to lay and medico-scientific terminology. We use different thesauri for this purpose and use the cosine similarity to measure the closeness of concepts with subsets of those thesauri. The evaluation of our approaches uses an existing glossary containing concepts in both terminologies in English and Portuguese and a and a set of queries submitted by users and classified by health professionals as lay or medical-scientific. We concluded that the best method to classify a concept uses the CHV vocabulary as a subset.

2019

Digital Bubbles: Living in Accordance with Personalized Seclusions and Their Effect on Critical Thinking

Autores
Ribeiro, B; Gonçalves, C; Pereira, F; Pereira, G; Santos, J; Gonçalves, R; Yong Oliveira, MA;

Publicação
New Knowledge in Information Systems and Technologies - Volume 3

Abstract
Since the emergence of the Global Village, the information flow changed drastically. Digital Technologies changed how people communicate, how they access information and how they share it. It gave people an unlimited exposure to information and knowledge. However, it also seemed to limit it. Recommendation algorithms are used in order to provide a customized experience that captivates users. Although they play an important role in selecting information that is considered relevant to the user, significant information/content may be omitted. Consequently, users end up closed in a bubble of limited information, which affects critical thinking skills and appears to influence and guide personal opinions. Little attention has been given to the negative effects of information bias on people’s critical thinking. Thus, it is hoped that this study will at the same time educate and bring awareness to this issue. In a survey we performed (with 117 answers) the majority of the survey sample (approximately 54,7%) revealed discomfort regarding the storage and filtering of data. Interestingly, 29,9% of the participants were found to be indifferent regarding this issue. From these results, the authors can conclude that, although most of the participants feel uncomfortable, they prefer to be passive about this, which reinforces the idea of conformity and the false sense of organization mentioned herein. An interview with an expert in the area drew attention to the fact that social pressure most often leads users to comply and rely on the group’s beliefs and attitudes, which facilitates social relationships and avoids confrontation. © Springer Nature Switzerland AG 2019.

2019

VisMillion: A novel interactive visualization technique for real-time big data

Autores
Pires, G; Mendes, D; Goncalves, D;

Publicação
PROCEEDINGS OF THE 2019 INTERNATIONAL CONFERENCE ON GRAPHICS AND INTERACTION (ICGI 2019)

Abstract
The rapid increase of connected devices causes more and more data to be generated and, in some cases, this data needs to be analyzed as it is received. As such, the challenge of presenting streaming data in such way that changes in the regular flow can be detected needs to be tackled, so that timely and informed decisions can be made. This requires users to be able to perceive the information being received in the moment in detail, while maintaining the context. In this paper, we propose VisMillion, a visualization technique for large amounts of streaming data, following the concept of graceful degradation. It is comprised of several different modules positioned side by side, corresponding to different contiguous time spans, from the last few seconds to a historical view of all data received in the stream so far. Data flows through each one from right to left and, the more recent the data, the more detailed it is presented. To this end, each module uses a different technique to aggregate and process information, with special care to ensure visual continuity between modules to facilitate the analysis. VisMillion was validated through a usability evaluation with 21 participants, as well as performance tests. Results show that it fulfills its objective, successfully aiding users to detect changes, patterns and anomalies in the information being received.

2019

Estudo de aplicabilidade do ensino edométrico a uma areia siltosa

Autores
Paula, António Miguel; Gonçalves, José; Batista, José; Braz-César, Manuel; Freitas, Bruno Afonso;

Publicação
ICEUBI2019 – International Congress on Engineering – Engineering for Evolution

Abstract
O presente artigo expõe o estudo de aplicabilidade do ensaio edométrico a uma areia siltosa, existente na cidade de Bragança, sendo que objetiva a aplicabilidade do ensaio aos solos de granulometria mais fina da região, com a ressalva de que a curva granulométrica destes se afasta de forma substancial das curvas granulométricas dos solos que por norma são alvo do ensaio edométrico. Objetiva assim o artigo, a aplicabilidade do ensaio aos solos mais finos oriundos de uma região com predominância de maciço residual granítico. Para tal, foram recolhidas amostras de dois solos com acentuada percentagem de finos, no contexto da predominância de solos da região, nomeadamente amostras indeformadas de uma areia siltosa, e amostras remexidas de um solo, posteriormente peneirado, com 100% de passados no peneiro nº 10, cuja granulometria corresponderá a um silte de elevada plasticidade. Devido à maior predominância de finos no silte de elevada plasticidade, o comportamento mecânico deste solo, mais condicionado por forças de natureza eletroquímica, representativo do comportamento dos solos finos, servirá de termo comparativo ao comportamento mecânico das amostras indeformadas de areia siltosa, com comportamento menos dependente destas forças, permitindo assim evidenciar a aplicabilidade do ensaio a solos de amostras indeformadas, com menor percentagem de finos, com comportamento gravítico mais acentuado e, portanto, mais atípicos a este ensaio devido à predominância de grossos na sua constituição. Dos resultados obtidos para a areia siltosa, verificou-se um elevado valor do assentamento imediato, após aplicação de cada ciclo de carga. Dado que a correta identificação do início do processo de consolidação carece de rigor no registo dos tempos de assentamento, fundamental para aplicação das metodologias de cálculo do ensaio, evidencia-se a necessidade de automatização de registo que minimize erros por parte de operadores humanos. Assim o recurso a um sistema de aquisição de dados revelou-se fundamental na identificação do início da consolidação primária, permitindo assim o alargar do espetro de aplicabilidade do ensaio.;This paper exposes the applicability study of the oedometer test to an existing silty sand soil, from the city of Braganza, with the purpose to verify the applicability of this test to soils with fines in his composition, in a region with predominance of granite residual soils, considering that the granulometric curve of these soils are substantially different from the granulometric curves of the soils that are usually tested. For this, two types of soils were collected, namely intact samples of a silty sand, and a disturbed soil sample whose grains size distribution curve built into laboratory corresponds to a high plasticity silt. Due to the greater predominance of fines in the high plasticity silt, the mechanical behaviour of this soil, more conditioned by forces of an electrochemical nature, serves as a comparative term to the mechanical behaviour of the undisturbed samples of the silty sand, with a behaviour less dependent on these forces, thus allowing to show applicability of the test to soils with lower percentage of fines, with a more pronounced gravitational behaviour and, therefore, more atypical to the oedometer test. From the results obtained for silty sand, a high value of the immediate settlement was verified after each applied load cycle. Thus this observation, the beginning of the consolidation process demands high accurate recording of the settlement that clearly identify the time that primary consolidation begins. In this way, the implementation of the data acquisition system, allowing the correct reading of the consolidation beginning, minimizing human errors, expands the spectrum of soils existing in the region that can be study by the consolidation problematics point of view.

2019

The search of conditional outliers

Autores
Portel, E; Ribeire, RP; Gama, J;

Publicação
INTELLIGENT DATA ANALYSIS

Abstract
There is no standard definition of outliers, but most authors agree that outliers are points far from other data points. Several outlier detection techniques have been developed mainly for two different purposes. On one hand, outliers are considered error measurement observations that should be removed from the analysis, e.g. robust statistics. On the other hand, outliers are the interesting observations, like in fraud detection, and should be modelled by some learning method. In this work, we start from the observation that outliers are affected by the so-called simpson paradox: a trend that appears in different groups of data but disappears or reverses when these groups are combined. Given a data set, we learn a regression tree. The tree grows by partitioning the data into groups more and more homogeneous of the target variable. At each partition defined by the tree, we apply a box plot on the target variable to detect outliers. We would expect that the deeper nodes of the tree would contain less and less outliers. We observe that some points previously signalled as outliers are no more signalled as such, but new outliers appear.

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