Cookies
O website necessita de alguns cookies e outros recursos semelhantes para funcionar. Caso o permita, o INESC TEC irá utilizar cookies para recolher dados sobre as suas visitas, contribuindo, assim, para estatísticas agregadas que permitem melhorar o nosso serviço. Ver mais
Aceitar Rejeitar
  • Menu
Publicações

2012

Methodologies to Determine Operating Reserves Due to Increased Wind Power

Autores
Holttinen, H; Milligan, M; Ela, E; Menemenlis, N; Dobschinski, J; Rawn, B; Bessa, RJ; Flynn, D; Gomez Lazaro, E; Detlefsen, NK;

Publicação
IEEE TRANSACTIONS ON SUSTAINABLE ENERGY

Abstract
Power systems with high wind penetration experience increased variability and uncertainty, such that determination of the required additional operating reserve is attracting a significant amount of attention and research. This paper presents methods used in recent wind integration analyses and operating practice, with key results that compare different methods or data. Wind integration analysis over the past several years has shown that wind variability need not be seen as a contingency event. The impact of wind will be seen in the reserves for nonevent operation ( normal operation dealing with deviations from schedules). Wind power will also result in some events of larger variability and large forecast errors that could be categorized as slow events. The level of operating reserve that is induced by wind is not constant during all hours of the year, so that dynamic allocation of reserves will reduce the amount of reserves needed in the system for most hours. The paper concludes with recent emerging trends.

2012

Gas refractometry based on an all-fiber spatial optical filter

Autores
Silva, S; Coelho, L; Andre, RM; Frazao, O;

Publicação
OPTICS LETTERS

Abstract
A spatial optical filter based on splice misalignment between optical fibers with different diameters is proposed for gas refractometry. The sensing head is formed by a 2 mm long optical fiber with 50 mu m diameter that is spliced with a strong misalignment between two single-mode fibers (SMF28) and interrogated in transmission. The misalignment causes a Fabry-Perot behavior along the reduced-size fiber and depending on the lead-out SMF28 position, it is possible to obtain different spectral responses, namely, bandpass or band-rejection filters. It is shown that the spatial filter device is highly sensitive to refractive index changes on a nitrogen environment by means of the gas pressure variation. A maximum sensitivity of -1390 nm/RIU for the bandpass filter was achieved. Both devices have shown similar temperature responses with an average sensitivity of 25.7 pm/degrees C. (C) 2012 Optical Society of America

2012

Image abstraction in crossmedia retrieval for text illustration

Autores
Coelho, F; Ribeiro, C;

Publicação
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract
Text illustration is a multimedia retrieval task that consists in finding suitable images to illustrate text fragments such as blog entries, news reports or children stories. In this paper we describe a crossmedia retrieval system which, given a textual input, selects a short list of candidate images from a large media collection. This approach makes use of a recently proposed method to map metadata and visual features into a common textual representation that can be handled by traditional information retrieval engines. Content-based analysis is enhanced by visual abstraction, namely the Anisotropic Kuwahara Filter, which impacts feature information captured by the Joint Composite and Speeded Up Robust Features visual descriptors. For evaluation purposes, we used the well-established MIRFlickr photo collection, with 25,000 photos and user tags collected from Flickr as well as manual annotations provided as image retrieval groundtruth. Results show that image abstraction can improve visual retrieval as well as significantly reduce processing and storage requirements, even more when paired with Google's WebP image format. We conclude that applying a visual rerank after an initial text retrieval step improves the quality of results, and that the adopted text mapping method for visual descriptors provides an effective crossmedia approach for text illustration. © 2012 Springer-Verlag Berlin Heidelberg.

2012

Online evaluation of a changes detection algorithm for depth of anesthesia signals ?

Autores
Sebastiao, R; Silva, MM; Rabico, R; Gama, J; Mendonca, T;

Publicação
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
The detection of changes in the signals used to evaluate the depth of anesthesia of patients undergoing surgery is of foremost importance. This detection allows to decide how to adapt the doses of hypnotics and analgesics to be administered to patients for minimally invasive diagnostics and therapeutic procedures. This paper presents an algorithm based on the Page-Hinkley test to automatically detect changes in the referred depth of anesthesia signals of patients undergoing general anesthesia. The performance of the proposed method is evaluated online using data from patients subject to surgery. The results show that most of the detected changes are in accordance with the actions of the clinicians in terms of times where a change in the hypnotic or analgesic rates had occurred. This detection was performed under the presence of noise and sensor faults. The results encourage the inclusion of the proposed algorithm in a decision support system based on depth of anesthesia signals. © 2012 IFAC.

2012

The scientific contribution of Leonor Vasconcelos Ferreira

Autores
Teixeira, AAC; Silva, S; Teixeira, P;

Publicação
Notas Económicas

Abstract

2012

Interrogation System Based on "Figure-of-Eight" Fiber Loop Mirror

Autores
Silva, RM; Layeghi, A; Zibaii, MI; Latifi, H; Santos, JL; Lobo Ribeiro, ABL; Frazao, O;

Publicação
22ND INTERNATIONAL CONFERENCE ON OPTICAL FIBER SENSORS, PTS 1-3

Abstract
A theoretical and experimental study of a new fiber loop mirror based on a "figure-of-eight" configuration, is reported. For the theoretical model, the Jones matrix analysis is analyzed. The configuration is tested as an interrogation system where the spectral response arises from the combination of the reference signal modulated by the sensor signal. The configuration is characterized in mechanical strain and presents a phase sensitivity of 8.2 mrad/mu epsilon.

  • 3455
  • 4493