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Publicações

2014

Classification of Optical Music Symbols based on Combined Neural Network

Autores
Wen, CH; Rebelo, A; Zhang, J; Cardoso, J;

Publicação
2014 INTERNATIONAL CONFERENCE ON MECHATRONICS AND CONTROL (ICMC)

Abstract
In this paper, a new method for music symbol classification named Combined Neural Network (CNN) is proposed. Tests are conducted on more than 9000 music symbols from both real and scanned music sheets, which show that the proposed technique offers superior classification capability. At the same time, the performance of the new network is compared with the single Neural Network (NN) classifier using the same music scores. The average classification accuracy increased more than ten percent, reaching 98.82%.

2014

Advanced experiments with an Erbium doped fiber laser

Autores
Marques, PVS; Marques, MB; Rosa, CC;

Publicação
12TH EDUCATION AND TRAINING IN OPTICS AND PHOTONICS CONFERENCE

Abstract
This communication describes an optical hands-on fiber laser experiment aimed at advanced college courses. Optical amplifiers and laser sources represent very important optical devices in numerous applications ranging from telecommunications to medicine. The study of advanced photonics experiments is particularly relevant at undergraduate and master level. This paper discusses the implementation of an optical fiber laser made with a cavity built with two tunable Bragg gratings. This scheme allows the students to understand the laser working principles as a function of the laser cavity set-up. One or both of the gratings can be finely tuned in wavelength through applied stress; therefore, the degree of spectral mismatch of the two gratings can be adjusted, effectively changing the cavity feedback. The impact of the cavity conditions on the laser threshold, spectrum and efficiency is analyzed. This experiment assumes that in a previous practice, the students should had already characterized the erbium doped fiber in terms of absorption and fluorescent spectra, and the spectral gain as a function of pump power.

2014

A Non-invasive Approach to Detect and Monitor Acute Mental Fatigue

Autores
Pimenta, A; Carneiro, D; Neves, J; Novais, P;

Publicação
IEA/AIE (2)

Abstract
In our day to day, we often experience a sense of being tired due to mental or physical workload. Along with that, there is also a feeling of degrading performance, even after the completion of simple tasks. These mental states however, are often not felt consciously or are ignored. This is an attitude that may result in human error, failure, and may lead to potential health problems together with a decrease in quality of life. States of acute mental fatigue may be detected with the close monitoring of certain indicators, such as productivity, performance and health indicators. In this paper, a model and prototype are proposed to detect and monitor acute acute fatigue, based on non-invasive Human-computer Interaction (HCI). This approach will enable the development of better working environments, with an impact on the quality of life and the work produced. © 2014 Springer International Publishing Switzerland.

2014

Improving the Energy Efficiency of WSN by Using Application-Layer Topologies to Constrain RPL-defined Routing Trees

Autores
Marques, BF; Ricardo, MP;

Publicação
2014 13TH ANNUAL MEDITERRANEAN AD HOC NETWORKING WORKSHOP (MED-HOC-NET)

Abstract
The deployment of thousands of tiny devices inter-networked together and accessible through the Internet is the result of the increasing trend towards enabling the concepts of Internet-of-Things. As these devices may be scattered in a unplanned way, a routing protocol is needed. The RPL protocol is the IETF proposed standard protocol for IPv6-based multi-hop Wireless Sensor Networks (WSN). RPL requires that communication paths go through a central router which may provide suboptimal paths, making no distinction of the applications the nodes run. To address these issues, an Application-Driven extension to RPL is proposed which enables the increase of the WSN lifetime by limiting the routing and forwarding functions of the network mainly to nodes running the same application. This paper evaluates the proposed solution coded in ContikiOS by means of Cooja simulations, and compares it against regular RPL. Simulation results confirm that the proposed solution provides lower energy consumption, lower end-to-end delays, and lower total number of packets transmitted and received.

2014

Online Traffic Prediction in the Cloud: A Dynamic Window Approach

Autores
Dalmazo, BL; Vilela, JP; Curado, M;

Publicação
2014 INTERNATIONAL CONFERENCE ON FUTURE INTERNET OF THINGS AND CLOUD (FICLOUD)

Abstract
Traffic prediction is a fundamental tool that captures the inherent behavior of a network and can be used for monitoring and managing network traffic. Online traffic prediction is usually performed based on large historical data used in training algorithms. This may not be suitable to highly volatile environments, such as cloud computing, where the coupling between observations decreases quickly with time. We propose a dynamic window size approach for traffic prediction that can be incorporated with different traffic predictions mechanisms, making them suitable to online traffic prediction by adapting the amount of traffic that must be analyzed in accordance to the variability of data traffic. The evaluation of the proposed solution is performed for several prediction mechanisms by assessing the Normalized Mean Square Error and Mean Absolute Percent Error of predicted values over observed values from a real cloud computing data set, collected by monitoring the utilization of Dropbox.

2014

Fluoroquinolone-metal complexes: A route to counteract bacterial resistance?

Autores
Feio, MJ; Sousa, I; Ferreira, M; Cunha Silva, L; Saraiva, RG; Queiros, C; Alexandre, JG; Claro, V; Mendes, A; Ortiz, R; Lopes, S; Amaral, AL; Lino, J; Fernandes, P; Silva, AJ; Moutinho, L; de Castro, B; Pereira, E; Perello, L; Gameiro, P;

Publicação
JOURNAL OF INORGANIC BIOCHEMISTRY

Abstract
Microbial resistance to antibiotics is one of the biggest public health threats of the modem world. Antibiotic resistance is an area of much clinical relevance and therefore research that has the potential to identify agents that may circumvent it or treat resistant infections is paramount. Solution behavior of various fluoroquinolone (FQ) complexes with copper(II) in the presence and absence of 1,10-phenanthroline (phen) was studied in aqueous solution, by potentiometry and/or spectrophotometiy, and are herein described. The results obtained showed that under physiological conditions (micromolar concentration range and pH 7.4) only copper(II):FQ:phen ternary complexes are stable. Hence, these complexes were synthesised and characterised by means of UV-visible and IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. In these complexes, the FQ acts as a bidentate ligand that coordinates the metal cation through the carbonyl and carboxyl oxygen atoms and phen coordinates through two N-atoms forming the equatorial plane of a distorted square-pyramidal geometry. The fifth position of the penta-coordinated Cu(II) centre is generally occupied axially by an oxygen atom from a water molecule or from a nitrate ion. Minimum inhibitory concentration (MIC) determinations of the complexes and comparison with free FQ in various E. coil strains indicate that the Cu-complexes are as efficient antimicrobials as the free antibiotic. Moreover, results strongly suggest that the cell intake route of both species is different supporting, therefore, the complexes' suitability as candidates for further biological testing in FQ-resistant microorganisms.

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