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
Publications

2003

Unchirped fiber Bragg grating for simultaneous filtering and dispersion compensation in wavelength-multiplexed systems

Authors
Lima, AJN; Teixeira, ALJ; da Rocha, JRF; Andre, PS; Frazao, O;

Publication
ICT'2003: 10TH INTERNATIONAL CONFERENCE ON TELECOMMUNICATIONS, VOLS I AND II, CONFERENCE PROCEEDINGS

Abstract
In this contribution we propose an alternative approach to the traditionally used apodized chirped fiber Bragg gratings for dispersion compensation applications. The unchirped grating proposed has a refractive index perturbation with varying negative mean, acting simultaneously as optical filter demultiplexer and efficient group velocity dispersion compensator in wavelength division multiplexing systems.

2003

Explosion of smoothness from a point to everywhere for conjugacies between diffeomorphisms on surfaces

Authors
Ferreira, F; Pinto, AA;

Publication
ERGODIC THEORY AND DYNAMICAL SYSTEMS

Abstract
For diffeomorphisms on surfaces with basic sets, we show the following type of rigidity result: if a topological conjugacy between them is differentiable at a point in the basic set then the conjugacy has a smooth extension to the surface. These results generalize the similar ones of D. Sullivan, E. de Faria and ours for one-dimensional expanding dynamics.

2003

A Probabilistic model for the cooperative modular neural network

Authors
Alexandre, LA; Campilho, A; Kamel, M;

Publication
PATTERN RECOGNITION AND IMAGE ANALYSIS, PROCEEDINGS

Abstract
This paper presents a model for the probability of correct classification for the Cooperative Modular Neural Network (CMNN). The model enables the estimation of the performance of the CMNN using parameters obtained from the data set. The performance estimates for the experiments presented are quite accurate (less than 1% relative difference). We compare the CMNN with a multi-layer perceptron with equal number of weights and conclude that the CMNN is preferred for complex problems. We also investigate the error introduced by one of the CMNN voting strategies.

2003

Towards Autonomy, Self-Organisation and Learning in Holonic Manufacturing

Authors
Leitão, P; Restivo, F;

Publication
Lecture Notes in Computer Science - Multi-Agent Systems and Applications III

Abstract

2003

Optimal detection of symmetry axis in digital chest X-ray images

Authors
Vinhais, C; Campilho, A;

Publication
PATTERN RECOGNITION AND IMAGE ANALYSIS, PROCEEDINGS

Abstract
We present a method for detecting the axis of bilateral symmetry in a digital chest X-ray image and subsequently measuring the degree of symmetry of the image. The detection is achieved by analysing rotated-reflected digital chest X-ray images and it is posed as a global optimization problem solved with a probabilistic genetic algorithm (PGA). The global search is initially based on natural peak orientation information related to the orientation of the symmetry axis. Only a few generations of the PGA are needed to achieve convergence to all the images in the database. This method is applied directly on the intensity input image and does not require any prior segmentation.

2003

Identification of adacor holons for manufacturing control

Authors
Leitao, P; Restivo, F;

Publication
INTELLIGENT MANUFACTURING SYSTEMS 2003

Abstract
The identification of the holons is a critical task in the development of holonic manufacturing control system applications. This paper discusses a methodology to develop distributed manufacturing control systems for the shop floor level, based on the ADACOR holonic architecture. The methodology comprises a set of steps, the more relevant being the identification of the manufacturing holons and the development of holons based on re-use libraries supported by the ADACOR approach. The paper focus on the first step and describes a procedure to identify the holons present in a manufacturing system. Copyright (C) 2003 IFAC.

  • 4342
  • 4542