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Publications

2007

A Methodology of Simplification of Interfaces with the e-Consumer

Authors
Mamede, HS; Santos, V; Lopes Costa, JAL;

Publication
NOVAS PERSPECTIVAS EM SISTEMAS E TECNOLOGIAS DE INFORMACAO, VOL I

Abstract

2007

Autonomous surface vehicle docking manoeuvre with visual information

Authors
Martins, A; Almeida, JM; Ferreira, H; Silva, H; Dias, N; Dias, A; Almeida, C; Silva, EP;

Publication
PROCEEDINGS OF THE 2007 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1-10

Abstract
This work presents a hybrid coordinated manoeuvre for docking an autonomous surface vehicle with an autonomous underwater vehicle. The control manoeuvre uses visual information to estimate the AUV relative position and attitude in relation to the ASV and steers the ASV in order to dock with the AUV. The AUV is assumed to be at surface with only a small fraction of its volume visible. The system implemented in the Autonomous Surface vehicle ROAZ, developed by LSA-ISEP to perform missions in river environment, test autonomous AUV docking capabilities and multiple AUV/ASV coordinated missions is presented. Information from a low cost embedded robotics vision system (LSAVision), along with inertial navigation sensors is fused in an extended kalman filter and used to determine AUV relative position and orientation to the surface vehicle The real time vision processing system is described and results are presented in operational scenario.

2007

Speaker segmentation of interviews using integrated video and audio change detectors

Authors
Lagrange, M; Martins, LG; Teixeira, LF; Tzanetakis, G;

Publication
2007 INTERNATIONAL WORKSHOP ON CONTENT-BASED MULTIMEDIA INDEXING, PROCEEDINGS

Abstract
In this paper, we study the use of audio and visual cues to perform speaker segmentation of audiovisual recordings of formal meetings such as interviews, lectures, or courtroom sessions. The sole use of audio cues for such recordings can be ineffective due to low recording quality and high level of background noise. We propose to use additional cues from the video stream by exploiting the relative static locations of speakers among the scene. The experiments show that the combination of those multiple cues helps to identify more robustly the transitions arriong speakers.

2007

Forest fire detection with a small fixed wing autonomous aerial vehicle

Authors
Martins, A; Almeida, J; Almeida, C; Figueiredo, A; Santos, F; Bento, D; Silva, H; Silva, E;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
In this work a forest fire detection solution using small autonomous aerial vehicles is proposed. The FALCOS unmanned aerial vehicle developed for remote-monitoring purposes is described. This is a small size UAV with onboard vision processing and autonomous flight capabilities. A set of custom developed navigation sensors was developed for the vehicle. Fire detection is performed through the use of low cost digital cameras and near-infrared sensors. Test results for navigation and ignition detection in real scenario are presented.

2007

A nonlinear model predictive control of an omni-directional mobile robot

Authors
Conceicao, AS; Oliveira, HP; e Silva, AS; Oliveira, D; Moreira, AP;

Publication
2007 IEEE INTERNATIONAL SYMPOSIUM ON INDUSTRIAL ELECTRONICS, PROCEEDINGS, VOLS 1-8

Abstract
This paper presents a nonlinear model based predictive controller (NMPC) for trajectory tracking of a mobile robot. Methods of numerical optimization to perform real time nonlinear minimization of the cost function are used. The cost function penalizes the robot position error, the robot orientation angle error and the control effort. Experimental results of the trajectories following and the performance of the methods of optimization are presented.

2007

An improved fuzzy inference system for voltage/VAR control

Authors
Miranda, V; Moreira, A; Pereira, J;

Publication
POWERENG2007: INTERNATIONAL CONFERENCE ON POWER ENGINEERING - ENERGY AND ELECTRICAL DRIVES PROCEEDINGS, VOLS 1 & 2

Abstract
This paper applies the concept of fuzzy controller to voltage/VAR control. Cascading Mamdani controllers are used together with sensitivities to keep voltages in an admissible band while avoiding line flows to exceed admissible limits. A small number of iteration steps with a Newton-Raphson power flow routine are enough to recover voltages into admissible bands.

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