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Publications

Publications by CRAS

1999

A reconfigurable mission control system for underwater vehicles

Authors
Silva, JE; Martins, A; Pereira, FL;

Publication
OCEANS '99 MTS/IEEE : RIDING THE CREST INTO THE 21ST CENTURY, VOLS 1-3

Abstract
This paper describes the mission control software used in the LSTS/FEUP underwater vehicles. This software follows the guidelines of the generalized vehicle architecture [1], adapts the original idea to encompass the current application requirements and constitutes a first implementation. The work is focused on the design and implementation of an application that can be easily adapted to different vehicle configurations or even to different vehicles. One of the desired goals was to enhance software reusability and to establish a development environment that allows developers with a minimal knowledge of coding details to upgrade the application. To assist this purpose, a CASE tool, which provides modern software development techniques, was used. A simulation environment was also developed whose purpose is to test the applications and to detect possible malfunctions before they occur during mission execution.

1999

Sequential extraction of components of multicomponent PPS signals

Authors
Oliveira, PM; Barroso, V;

Publication
ICASSP '99: 1999 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH, AND SIGNAL PROCESSING, PROCEEDINGS VOLS I-VI

Abstract
A procedure for parameter estimation of multicomponent Polynomial Phase Signals is presented. This scheme, while restricted to high SNR's, has the advantage of being extremely simple. It is also insensitive to the equal-coefficient identifiability problem of HAF (High-order Ambiguity Function) based methods. It poses, however, some restrictions on the component amplitudes. Its performance in noise is investigated, and confirmed with several examples.

1999

Instantaneous frequency of multicomponent signals

Authors
Oliveira, PM; Barroso, V;

Publication
IEEE SIGNAL PROCESSING LETTERS

Abstract
The failure of the traditional definition of instantaneous frequency (IFt) in the multicomponent case has been often reported, We will determine the reasons for failure of this definition, That will enable us to understand and integrate all previously reported cases in a simple unified theory. As a direct consequence, we will be able to extrapolate and predict the behavior of the traditional definition for any type of multicomponent signal.

1999

Shallow seismic reflection results in the Vouga basin region (Northern Portugal)

Authors
Marques Moura, R; Senos Matias, M;

Publication
5th EEGS-ES Meeting

Abstract

1999

Impact shear wave generator for dynamic shallow soil characterisation

Authors
E. Almeida, F; Marques Moura, R;

Publication
5th EEGS-ES Meeting

Abstract

1998

Flexible hardware acceleration for nesting problems

Authors
Ferreira, JC; Alves, JC; Albuquerque, C; Oliveira, JF; Ferreira, JS; Matos, JS;

Publication
5th IEEE International Conference on Electronics, Circuits and Systems, ICECS 1998, Surfing the Waves of Science and Technology, Lisbon, Portugal, September 7-10, 1998

Abstract
The nesting (or placement) problem is an NP-hard combinatorial problem with important industrial applications, e.g. in apparel or footwear industry. This paper describes a hardware infrastructure to accelerate the processing of the underlying geometric information. The system consists of an FPGA-based reconfigurable platform enhanced by an ASIC for the processing of irregular polygons. The paper discusses the need for such a platform, establishes the main design guidelines and describes the architecture and modes of operation of both the reconfigurable infrastructure and the dedicated IC.

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