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Publications

Publications by José Alexandre Gonçalves

2019

Computational thinking and robotics in education

Authors
García P?alvo, FJ; Conde, MA; Gonçalves, J; Lima, J;

Publication
ACM International Conference Proceeding Series

Abstract
After the computational thinking sessions in the previous 2016-2018 editions of TEEM Conference, the fourth edition of this track has been organized in the current 2019 edition. Computational thinking is still a very significant topic, especially, but not only, in pre-university education. In this edition, the robotic has a special role in the track, with a strength relationship with the STEM and STEAM education of children at the pre-university levels, seeding the future of our society. © 2019 ACM.

2019

Development of a brain emotional learning based controller for application to vibration control of a building structure under seismic excitation

Authors
Braz César, M; Gonçalves, J; Coelho, J; Barros, R;

Publication
COMPDYN Proceedings

Abstract
In this paper, a numerical simulation of a semi-active neuroemotional based control system for vibration reduction of a 3-story framed building structure under seismic excitation is presented. The Brain Emotional Learning Based Intelligent Controller (BELBIC) is used to design a closed-loop control system that determines the required control action (emotional response) based on the desired and actual system response (sensory input). In this case, the control signal is used to adjust in real time the damping force of a MagnetoRheological (MR) damper to reduce the system response. The results obtained from the numerical simulation validate the effectiveness of the brain emotional learning semi-active controller in improving the overall response of the structural system. © 2019 The authors.

2019

Educational robotics summer camp at IPB: A challenge based learning case study

Authors
Gonçalves, J; Lima, J; Brito, T; Brancalio, L; Camargo, C; Oliveira, V; Conde, MA;

Publication
ACM International Conference Proceeding Series

Abstract
Robotics in education has special relevance in current digital society where students should know how to deal with technology. In this paper, it is presented an educational experiment in the mobile robotics domain. The referred experiment was part of a summer camp, which took place at the Polytechnic Institute of Bragança Portugal, being its technological aspects related with mobile robotics. Other than the technological aspects, the students participated in many different cultural and social activities, having the opportunity to know the city of Bragança and also to know different persons, mainly students, professors, researchers and laboratory technicians. The applied approach in the summer camp was a challenge based learning methodology, being involved in the experiment 3 professors, 4 monitors, working with a group of 16 secondary school students. The described experiment was planned as an activity of the RoboSTEAM - Integrating STEAM and Computational Thinking development by using robotics and physical devices ERASMUS+ Project. © 2019 ACM.

2019

RoboSTEAM - A challenge based learning approach for integrating STEAM and develop Computational Thinking

Authors
Conde, MA; Fernández, C; Alves, J; Ramos, MJ; Celis Tena, S; Gonçalves, J; Lima, J; Reimann, D; Jormanainen, I; P?alvo, FJG;

Publication
ACM International Conference Proceeding Series

Abstract
We live in a digital society that needs new better prepared professionals for the new challenges and opportunities provided by the ICT. Students must learn how to deal with all the issues that emerge in this new context. They should acquire computational thinking skills by integrating STEAM, however this needs for changes in current learning curricula and also new learning approaches. RoboSTEAM project deals with this issue by the application of a Challenge Based Learning approach that uses Robotics and Physical Devices. One of the problems found during the project is the complexity of the application of a Challenge Based Learning approach due to the special needs of each educational institution. Given this situation the present work presents provides a flexible definition of challenge and describes also samples regarding how to use them. © 2019 ACM.

2019

Semi-Active Vibration Control of a Non-Collocated Civil Structure Using Evolutionary-Based BELBIC

Authors
Cesar, MB; Coelho, JP; Goncalves, J;

Publication
ACTUATORS

Abstract
A buildings resilience to seismic activity can be increased by providing ways for the structure to dynamically counteract the effect of the Earth's crust movements. This ability is fundamental in certain regions of the globe, where earthquakes are more frequent, and can be achieved using different strategies. State-of-the-art anti-seismic buildings have, embedded on their structure, mostly passive actuators such as base isolation, Tuned Mass Dampers (TMD) and viscous dampers that can be used to reduce the effect of seismic or even wind induced vibrations. The main disadvantage of this type of building vibration reduction strategies concerns their inability to adapt their properties in accordance to both the excitation signal or structural behaviour. This adaption capability can be promoted by adding to the building active type actuators operating under a closed-loop. However, these systems are substantially larger than passive type solutions and require a considerable amount of energy that may not be available during a severe earthquake due to power grid failure. An intermediate solution between these two extremes is the introduction of semi-active actuators such as magneto-rheological dampers. The inclusion of magneto-rheological actuators is among one of the most promising semi-active techniques. However, the overall performance of this strategy depends on several aspects such as the actuators number and location within the structure and the vibration sensors network. It can be the case where the installation leads to a non-collocated system which presents additional challenges to control. This paper proposes to tackle the problem of controlling the vibration of a non-collocated three-storey building by means of a brain-emotional controller tuned using an evolutionary algorithm. This controller will be used to adjust the stiffness coefficient of a magneto-rheological actuator such that the building's frame oscillation under earthquake excitation, is mitigated. The obtained results suggest that, using this control strategy, it is possible to reduce the building vibration to secure levels.

2021

Experimental and numerical study to minimize the residual stresses in welding of 6082-T6 aluminum alloy

Authors
Costa, S; Souza, MS; Cesar, MB; Goncalves, J; Ribeiro, JE;

Publication
AIMS MATERIALS SCIENCE

Abstract
One of the most important negative consequence in the fusion welding processes is the generation of tensile residual stresses in welded joints. The main goals of this work are to determine the optimal combination of welding parameters to minimize the residual stress level and the influence of each welding parameter in that feature to weld 6082-T6 aluminum alloy plates using the GMAW welding process. To achieve these goals was implemented the Taguchi orthogonal array (L27) to define the design of numerical and experimental tests. All combinations were simulated in the Simufactwelding 6.0 software, from which it was possible to obtain the values of maximum residual stresses. The data treatment was carried out, reaching the combination of levels for each parameter. With ANOVA analysis was found that the parameter with the greatest influence in the residual stress generation was the welding speed, while the parameter with the least influence was the torch angle. Also, to minimize the residual stresses it was observed that the optimal combination of welding parameters is welding current intensity of 202 A, welding speed of 10 mm/s, and 30 degrees of inclination of the angular torch. The two simulations that resulted in the highest and lowest residual stresses were validated experimentally by the hole drilling method to measure the residual stresses.

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