2009
Authors
Ramos, S; Khodr, HM; Azevedo, F; Vale, Z;
Publication
2009 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, VOLS 1-8
Abstract
This paper presents a methodology supported on the data base knowledge discovery process (KDD), in order to find out the failure probability of electrical equipments', which belong to a real electrical high voltage network. Data Mining (DM) techniques are used to discover a set of outcome failure probability and, therefore, to extract knowledge concerning to the unavailability of the electrical equipments such us power transformers and high-voltages power lines. The framework includes several steps, following the analysis of the real data base, the pre-processing data, the application of DM algorithms, and finally, the interpretation of the discovered knowledge. To validate the proposed methodology, a case study which includes real databases is used. This data have a heavy uncertainty due to climate conditions for this reason it was used fuzzy logic to determine the set of the electrical components failure probabitities in order to reestablish the service. The results reflect an interesting potential of this approach and encourage further research on the topic.
2009
Authors
Ferreira, LA; Farinha, JT; Barbosa, FM; Fonseca, I;
Publication
ENERGY PROBLEMS AND ENVIRONMENTAL ENGINEERING
Abstract
In a global world, the survival and sustainability of industrial companies depends on several factors: production continuity; quantity assurance; quality assurance; competitive prices for products; on time production; flexibility; operational safety and environmental safety. To achieve these goals, sustainable industrial operations must rely on dependable systems and equipments. Dependability is defined as "the collective term describing the availability performance of any simple to complex product" [1]. This definition can be extended for industrial operations, to their reliability and maintainability design characteristics. As there are no perfect systems and equipments designs, component degradation and failures will always occur during their life cycle. So to keep their dependability level during the life cycle good maintenance support is essential. In this paper we will discuss the importance of maintenance to achieve the required dependability and sustainability for industrial production processes and how that can be achieved.
2009
Authors
Ferreira, A;
Publication
E-BUSINESS AND TELECOMMUNICATIONS
Abstract
Human recognition of isolated vowels is quite robust considering intra and inter-speaker variability. Automatic recognition techniques typically exhibit poor performances, notably in the case of female or child speech because a higher fundamental frequency (F0) generates a sparser sampling of the magnitude spectrum. In this paper we extend previous results on a perceptually motivated concept of vowel recognition that is based on Perceptual Spectral Clusters (PSC) of harmonic partials. We study the effect of normalizing relevant PSC features by F0 taking as a reference the recognition performance of static features derived from either Linear Prediction (LP) analysis or Mel-Frequency Cepstral Coefficients (MFCC), and using the Mahalanobis distance on a data base of five natural Portuguese vowel sounds uttered by 44 speakers. Test results reveal that the recognition performance of F0-normalized PSC features increases approaching that of MFCC coefficients. These results are significant as PSC related features are amenable to concurrent vowel identification while LP or MFCC-related features are not.
2009
Authors
Pessoa, LM; Salgado, HM; Darwazeh, I;
Publication
IEEE PHOTONICS TECHNOLOGY LETTERS
Abstract
We assess the performance of a coherent optical system employing a phase estimation algorithm combined with a least mean square decision-directed equalizer in a feedback configuration and compare it to the constant modulus algorithm with an independent carrier phase estimation approach for 16-quadratic-amplitude-modulation transmission. Both series and parallel implementations are discussed. Hardware issues regarding a recursive implementation of the estimation filter are also reported.
2009
Authors
Travassos Valdez, MMT; Faustino Agreira, CIF; Machado Ferreira, CMM; Maciel Barbosa, FPM;
Publication
UPEC: 2009 44TH INTERNATIONAL UNIVERSITIES POWER ENGINEERING CONFERENCE
Abstract
An engineering curriculum requires that its future professionals should be fully prepared to accomplish a variety of tasks involving not only theoretical concepts, but also skills acquired through effective practice. In the Instituto Superior de Engenharia de Coimbra (ISEC), Department of Electrical Engineering, preference was given to apply methods integrating technology in the learning and then evaluating the outcomes. Problem-based learning (PBL) was used as an instructional strategy of active learning, and adapted for use in the Lighting Design course. The students are presented with a virtual scenario, quite similar to the real world, where they are required to perform as they would in a real life situation. The emphasis is given to PBL so that they can learn to become autonomous, skilled and explore their own potential as well as improve team work skills/spirit and that can be applied to a wide range of students and subject matters. PBL is introduced to the students as a 'learn by doing' project. The project incorporates aspects of electrical engineering and computing skills. This study analyses the learning process/techniques that help students deal with the complexity of a Lighting Design Project and assesses its effectiveness and impact on the students. Essentially, it encourages them to be in charge of their education. The benefits of PBL in the Lighting Design course are visible in the improvement of the study and analysis of a Lighting Design project. The method may also bring benefits for Electrical Engineering programmes where educators struggle for improved teaching and learning. The simulation was performed using the Dialux 4.3 software package that runs in Windows Vista or XP environment.
2009
Authors
Rodrigues, N; Oliveira, L; Coelho, A;
Publication
Proceedings of the IADIS International Conference WWW/Internet 2009, ICWI 2009
Abstract
Rich Internet Applications (RIA) technology leads to new opportunities in Web development, adding a new level of usability and overcoming several limitations of traditional Web applications. However, there are still a few gaps in RIA development, namely the lack of methodologies enabling direct evolution of traditionally developed Web applications into this new concept. This paper describes a methodology to adapt User Interfaces (UI) from Web 1.0 into Web 2.0 introducing RIA capabilities, maintaining the business logic and data access layers legacy. The main system architecture is maintained and the new concept is achieved by adding a new Web services encapsulation layer responsible to intermediate the business logic layer and the new UI layer, providing a seamless and dynamic integration. For validating this methodology, a prototype was developed by applying and evaluating the suggested methodology. The results obtained validate that this methodology is appropriate for the given problem. © 2009 IADIS.
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