Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Interest
Topics
Details

Details

  • Name

    Nelson Bilber Rodrigues
  • Cluster

    Computer Science
  • Role

    Assistant Researcher
  • Since

    20th February 2006
Publications

2023

Intelligent Wheelchairs Rolling in Pairs Using Reinforcement Learning

Authors
Rodrigues, N; Sousa, A; Reis, LP; Coelho, A;

Publication
ROBOT2022: FIFTH IBERIAN ROBOTICS CONFERENCE: ADVANCES IN ROBOTICS, VOL 2

Abstract
Intelligent wheelchairs aim to improve mobility limitations by providing ingenious mechanisms to control and move the chair. This paper aims to enhance the autonomy level of intelligent wheelchair navigation by applying reinforcement learning algorithms to move the chair to the desired location. Also, as a second objective, add one more chair and move both chairs in pairs to promote group social activities. The experimental setup is based on a simulated environment using gazebo and ROS where a leader chair moves towards a goal, and the follower chair should navigate near the leader chair. The collected metrics (time to complete the task and the trajectories of the chairs) demonstrated that Deep Q-Network (DQN) achieved better results than the Q-Learning algorithm by being the unique algorithm to accomplish the pair navigation behaviour between two chairs.

2022

Influence of the underwater environment in the procedural generation of marine alga Asparagopsis Armata

Authors
Rodrigues, N; Sousa, AA; Rodrigues, R; Coelho, A;

Publication
Journal of WSCG

Abstract
Content generation is a heavy task in virtual worlds design. Procedural content generation techniques aim to agile this process by automating the 3D modelling with some degree of parametrisation. The novelty of this work is the procedural generation of the marine alga (Asparagopsis armata), taking into consideration the underwater environmental factors. The depth and the occlusion were the two parameters in this study to simulate how the alga growth is influenced by the environment where the alga grows. Starting by building a prototype to explore different L-systems categories to model the alga, the stochastic L-systems with parametric features were selected to generate different alga plasticities. Qualitative methods were used to evaluate the designed grammar and alga’s animation results by comparing videos and images of the Asparagopsis armata with the computer-generated versions. © 2022, Vaclav Skala Union Agency. All rights reserved.

2022

Influence of the underwater environment in the procedural generation of marine alga Asparagopsis Armata

Authors
Rodrigues, N; Sousa, AA; Rodrigues, R; Coelho, A;

Publication
Computer Science Research Notes

Abstract
Content generation is a heavy task in virtual worlds design. Procedural content generation techniques aim to agile this process by automating the 3D modelling with some degree of parametrisation. The novelty of this work is the procedural generation of the marine alga (Asparagopsis armata), taking into consideration the underwater environmental factors. The depth and the occlusion were the two parameters in this study to simulate how the alga growth is influenced by the environment where the alga grows. Starting by building a prototype to explore different L-systems categories to model the alga, the stochastic L-systems with parametric features were selected to generate different alga plasticities. Qualitative methods were used to evaluate the designed grammar and alga's animation results by comparing videos and images of the Asparagopsis armata with the computer-generated versions. © 2022 University of West Bohemia. All rights reserved.

2021

Integration of CAD Models into Game Engines

Authors
Santos, B; Rodrigues, N; Costa, P; Coelho, A;

Publication
GRAPP: PROCEEDINGS OF THE 16TH INTERNATIONAL JOINT CONFERENCE ON COMPUTER VISION, IMAGING AND COMPUTER GRAPHICS THEORY AND APPLICATIONS - VOL. 1: GRAPP

Abstract
Computer-aided design (CAD) and 3D modeling are similar, but they have different functionalities and applications. CAD is a fundamental tool to create object models, design parts, and create 2D schematics from 3D designed objects that can later be used in manufacturing. Meanwhile, 3D modeling is mostly used in entertainment, to create meshes for animation and games. When there is the necessity of using real-life object models in game engines, a conversion process is required to go from CAD to 3D meshes. Converting from the continuous domain of CAD to the discrete domain of 3D models represents a trade-off between processing cost and visual accuracy, in order to obtain the best user experience. This work explores different methods for the creation of meshes and the reduction of the number of polygons used to represent them. Based on these concepts, an interactive application was created to allow the users to control how the model looks in the game engine, in a simple way, while also optimizing and simplifying the mapping of textures for the generated meshes. This application (CADto3D) generates accurate 3D models based on CAD surfaces while giving the user more control over the final result than other current solutions.