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Publications

The Effect of a Linear Tuning between the Antigenic Stimulations of CD4+ T Cells and CD4+ Tregs

Publication . Yusuf, Aliyu; Figueiredo, Isabel; Afsar, Atefeh; Burroughs, Nigel; Pinto, Alberto; Oliveira, Bruno

We study the equilibria of an Ordinary Differencial Equation (ODE) system where CD4 + effector or helper T cells and Regulatory T cells (Tregs) are present. T cells trigger an immune response in the presence of their specific antigen. Regulatory T cells (Tregs) play a role in limiting auto-immune diseases due to their immune-suppressive ability. Here, we present explicit exact formulas that give the relationship between the concentration of T cells, the concentration of Tregs, and the antigenic stimulation of T cells, when the system is at equilibria, stable or unstable. We found a parameter region of bistability, limited by two thresholds of antigenic stimulation of T cells (hysteresis). Moreover, there are values of the slope parameter of the tuning for which an isola-center bifurcation appears, and, for some other values, there is a transcritical bifurcation. We also present time evolutions of the ODE system.

2020Journal article

Open access

Multipurpose Urban Sensing Equipment—An EPS@ISEP 2018 Project

Publication . Farrag, Mostafa; Marques, Damien; Bagiami, Maria; van der Most, Maarten; Smit, Wouter; Malheiro, Benedita; Castro Ribeiro, Maria Cristina de; Justo, Jorge Fonseca; Silva, Manuel; Ferreira, Paulo; Guedes, Pedro

This paper describes the development of a Multi-purpose Urban Sensing Equipment, named Billy, designed by a multinational and multidisciplinary team enrolled in the European Project Semester (EPS) at Instituto Superior de Engenharia do Porto (ISEP). The project is set to design, develop and test an interactive billboard in compliance with the relevant EU regulation and the allocated budget. The Team benefited from the different background, multidisciplinary skills and the newly acquired skills of the members, like marketing, sustainability and design ethics, in activities both inside and outside of the University. The challenge was to design a multi-purpose urban sensing and displaying equipment to inform citizens of nearby environmental conditions. The Team decided to design a system to monitor and display the temperature, humidity, air pressure and air quality of leisure areas, featured with a proximity detection sensor for energy saving. Billy will not only monitor and display this local information, but also the air quality determined by other billboards placed in other locations, creating a distributed urban sensing network. The system has been successfully prototyped and tested using the ESPduino Wi-Fi enabled micro-controller, different sensors and displays (screen and map-based). The results show not only that the prototype functions according to derived specifications and design, but that the team members were able to learn, together and from each other, how to solve this multidisciplinary problem.

2019Book part

Open access

APASail—An Agent-Based Platform for Autonomous Sailing Research and Competition

Publication . Alves, Bruno; Veloso, Bruno; Malheiro, Benedita

This paper presents a platform for real and simulated autonomous sailing competitions, which can also be used as a research tool to test and assess navigation algorithms. The platform provides back-end services – competition server, boat modelling and data storage – and supports external browsers and software agents as front-end clients. The back-end adopts the Multi-Agent System (MAS) paradigm for the internal modelling of sailing boats and offers a Web Service Application Programming Interface (API) for the external software agents and a Web application for Web browsers. As a whole, the platform offers tracking (real competitions) and simulation (simulated competitions) modes. The testing and assessment of navigation algorithms and boat models correspond to private simulated competitions. In simulation mode, the back-end internal boat agent implements a simplified physical model, including the weight, sail area, angle of the sail and rudder, velocity and direction of the wind and position and velocity of the hull, whereas the front-end external boat agent implements the navigation algorithm on the team side, ensuring the privacy of strategic knowledge. The Web application allows the configuration and launching of competitions, the registration of teams and researchers, the uploading of boat physical features for simulation as well as the live or playback viewing of real and simulated competitions. The simulation mode is illustrated with the help of a case study. The proposed platform, which is open, scalable, modular and distributed, was designed for the research community to prepare, run and gather data from real and simulated autonomous sailing competitions.

2018Book part

Open access