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Publicações

2020

Flexible Baseband Modulator Architecture for Multi-Waveform 5G Communications

Autores
Lopes Ferreira, M; Canas Ferreira, J;

Publicação
Field Programmable Gate Arrays (FPGAs) II

Abstract

2020

Compensation Scheme With Shapley Value For Multi-Country Kidney Exchange Programmes

Autores
Biro, P; Gyetvai, M; Klimentova, X; Pedroso, JP; Pettersson, W; Viana, A;

Publicação
ECMS 2020 Proceedings edited by Mike Steglich, Christian Mueller, Gaby Neumann, Mathias Walther

Abstract

2020

Manipulation of the Fundamental Frequency Micro-Variations using a Fully Parametric and Computationally Efficient Speech Model

Autores
Silva, JP; Oliveira, MA; Cardoso, CF; Ferreira, AJ;

Publicação
IEEE Workshop on Signal Processing Systems, SiPS: Design and Implementation

Abstract
In this paper, we present a computationally efficient and fully parametric harmonic speech model that is suitable for real-time flexible frame-based analysis and synthesis implementation in the frequency domain. We carry out a performance comparison between this vocoder and similar ones, such as WORLD and HPMD. Then, a deliberate manipulation of the speaker's fundamental frequency micro-variations is performed in order to understand in which way it conveys prosodic and idiosyncratic information. We conclude our discussion by evaluating the impact of these manipulations through the realization of perceptual tests. © 2020 IEEE.

2020

Electronic games as a touristic promotional tool

Autores
Esteves F.; Brito P.Q.;

Publicação
Handbook of Research on Resident and Tourist Perspectives on Travel Destinations

Abstract
According to the World Tourism Organization (UNWTO), in 2017 tourism had the greatest international growth in seven years, and in 2018, international tourism grew 5% reaching the mark of 1.4 billion, a figure reached two years earlier than predicted. At the same time, in the last 40 years, the video game industry has grown steadily, with games beginning to be seen as one of the primary sources of entertainment. However, there are still few studies analyzing the impact of advertising tourist destinations on digital platforms such as video games. The use of video games in the tourist context may be an inspirational tool, supporting the development of new advertising strategies for tourism marketing. Although the connection between tourism and cinema is widely documented, little research has demonstrated a credible correlation between video games and tourists' attitude towards destinations.

2020

A Study on Imbalanced Data Streams

Autores
Aminian, E; Ribeiro, RP; Gama, J;

Publicação
MACHINE LEARNING AND KNOWLEDGE DISCOVERY IN DATABASES, ECML PKDD 2019, PT II

Abstract
Data are growing fast in today's world and great portion of that is in the form of stream. In many situations, data streams are imbalanced making it difficult to use with classical data mining methods. However, mining these special kinds of streams is one of the most attractive research area. In this paper, we propose two algorithms for learning from imbalanced regression data streams. Both methods are based on Chebychev's inequality but in a different way. The first method, under-samples from the frequent target value examples while the second method over-samples the rare and extreme target value examples. This way, the learner will focus in the rare and more difficult cases. We applied our methods to train regression models using two benchmark datasets and two well-known regression algorithms: Perceptron and FIMT-DD. Our obtained results from the simulations indicate the usefulness of our proposed methods.

2020

Biot-Granier Sensor: A Novel Strategy to Measuring Sap Flow in Trees

Autores
Siqueira, JM; Paco, TA; da Silva, JM; Silvestre, JC;

Publicação
SENSORS

Abstract
The Biot-Granier (Gbt) is a new thermal dissipation-based sap flow measurement methodology, comprising sensors, data management and automatic data processing. It relies on the conventional Granier (Gcv) methodology upgraded with a modified Granier sensor set, as well as on an algorithm to measure the absolute temperatures in the two observation points and perform the Biot number approach. The work described herein addresses the construction details of the Gbt sensors and the characterization of the overall performance of the Gbt method after comparison with a commercial sap flow sensor and independent data (i.e., volumetric water content, vapor pressure deficit and eddy covariance technique). Its performance was evaluated in three trials: potted olive trees in a greenhouse and two vineyards. The trial with olive trees in a greenhouse showed that the transpiration measures provided by the Gbt sensors showed better agreement with the gravimetric approach, compared to those provided by the Gcv sensors. These tended to overestimate sap flow rates as much as 4 times, while Gbt sensors overestimated gravimetric values 1.5 times. The adjustments based on the Biot equations obtained with Gbt sensors contribute to reduce the overestimates yielded by the conventional approach. On the other hand, the heating capacity of the Gbt sensor provided a minimum of around 7 degrees C and maximum about 9 degrees C, contrasting with a minimum around 6 degrees C and a maximum of 12 degrees C given by the Gcv sensors. The positioning of the temperature sensor on the tip of the sap flow needle proposed in the Gbt sensors, closer to the sap measurement spot, allow to capture sap induced temperature variations more accurately. This explains the higher resolution and sensitivity of the Gbt sensor. Overall, the alternative Biot approach showed a significant improvement in sap flow estimations, contributing to adjust the Granier sap flow index, a vulnerability of that methodology.

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