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Publications

The K-framed quadtrees approach for path planning through a known environment

Publication . Rodrigues, Ana Rita Marques; Costa, Pedro; Lima, José

One of the most important tasks for a mobile robot is to navigate in an environment. The path planning is required to design the trajectory that generates useful motions from the original to the desired position. There are several methodologies to perform the path planning. In this paper, a new method of approximate cells decomposition, called K-Framed Quadtrees is present, to which the algorithm A â‹† is applied to determine trajectories between two points. To validate the new approach, we made a comparative analysis between the present method, the grid decomposition, quadtree decomposition and framed quadtree decomposition. Results and implementation specifications of the four methods are presented.

2018Conference object

Open access

Proposal of a new servo-motor optimized for educational robotic applications

Publication . Silva, João; Costa, Paulo Gomes da; Gonçalves, José

This paper describes the development of SMORA (Servo Motor Optimised for Robotic Applications), which consists of custom hardware and firmware that includes a microcontroller and a series of sensors, allowing for the motor current, temperature and voltage to be measured in real-time as well as precise position feedback thanks to the integrated hall-effect magnetic position encoder. It also incorporates an accelerometer and a gyroscope to measure the servo body relative position and rotation.

2017Conference object

Restricted access

An application of DEA to the third sector: the case of children and youth households

Publication . Vaz, Clara B.; Mendes, Ivo; Alves, Jorge

The Portuguese state has transferred some areas of its social program for third sector entities, including private social welfare institutions. This transfer of powers is supported by providing economic subsidies, being public entities responsible to monitor the efficient management by those institutions. This research aims to present a contribution to monitor the efficient management of resources by the institutions that look after children and young people. The DEA method is used to assess the technical efficiency of eight institutions from Bragança district, during the years 2010 to 2013. This model evaluates each institution in reduction of resource levels used to provide social services to the level of users observed in each unit. This approach should be used to complement the assessment of quality in providing social services, which is currently performed by the regulator, in order to allow monitoring the overall performance of such institutions.

2015Conference object

Open access

Accessible software development: a conceptual model proposal

Publication . Silva, João Sousa e; Gonçalves, Ramiro Manuel; Branco, Frederico; Pereira, António Manuel; Oliveira, Manuel Au-Yong; Martins, José

Equal access to all software and digital content should be a reality in the Digital Era. This argument is something defended both by existing regulations, norms and standards, and also business organizations and governments. Despite this acknowledgement, the reality is still far from the desired equality. For certain groups of disabled or impaired citizens, such as the visually impaired, the existence of e-accessibility compliance represents an opportunity to integrate, in a more simple and straightforward manner, their societies. Despite the existing poor results on e-accessibility compliance, the mentioned citizens insist on using digital devices in their daily lives. Even though, in the last decade, multiple standards and regulations have been published towards indicating how to develop accessible digital user interfaces, there are still two major issues surrounding its implementation: the complexity and disparity of the documents containing the abovementioned norms, and also the lack of e-accessibility know-how by software experts. With this in mind, a proposal for an accessible software development model that encompasses e-accessibility incorporation as one of the development process activities has been presented. This model might represent a very interesting support tool for software development organizations and a novel resource for learning and training institutions to be able to improve their computer science and informatics students’ skills on e-accessibility.

2019Journal article

Open access

Indoor environment monitoring in search of gas leakage by mobile robot

Publication . Braun, João; Piardi, Luis; Brito, Thadeu; Lima, José; Pereira, Ana I.; Costa, Paulo Gomes da; Nakano, Alberto Yoshiro

Inspection based on mobile autonomous robots can assume an important role in many industries. Instead of having fixed sensors, the concept of assembling the sensors on a mobile robot that performs the scanning and inspection through a defined path is cheaper, configurable and adaptable. This paper describes a mobile robot, equipped with several gas sensors and a LIDAR device, that scans an established area by following a trajectory based on way-points searching for gas leakage and simultaneously avoid obstacles in the map. In other words, the robot follows the trajectory while the gas concentration is under a defined value and surrounding the obstacles. Otherwise, the autonomous robot starts the leakage search based on a search algorithm that allows to find the leakage position. The proposed methodology is verified in simulation based on a model of the real robot. The search test performed in a simulation environment allows to validate the proposed methodology.

2020Conference object

Open access