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Publicações

Publicações por CSE

2022

Extreme heat events in the Iberia Peninsula from extreme value mixture modeling of ERA5-Land air temperature

Autores
Barbosa, S; Scotto, MG;

Publicação
WEATHER AND CLIMATE EXTREMES

Abstract
Extreme summer temperatures in the Iberia Peninsula are analyzed from ERA5-Land reanalysis data based on an extreme value mixture model combining a Normal distribution for the bulk distribution (i.e. for the non-extreme values) and a Generalized Pareto Distribution for the extremes in the upper tail. This approach allows to treat the threshold of temperature exceedances as being one of model parameters rather than fixed a priori, enabling to take into account its corresponding uncertainty. Extreme value mixture models are estimated individually for each location, and the analysis is performed separately for two distinct periods, namely from 1981 to 2000 and from 2000 to 2019, respectively. The results show significant differences in the extreme value mixture models for the two periods, and in their corresponding 20-year return levels. The mean of the bulk distribution of summer maximum temperature increases significantly, particularly in Eastern Iberia. The largest differences in the tails of the data distribution between the two periods occur in the eastern Mediterranean area, and are characterized by a significant increase in the threshold for temperature exceedances and in their corresponding return levels.

2022

Using Virtual Reality to Demonstrate and Promote Products: The Effect of Gender, Product Contextualization and Presence on Purchase Intention and User Satisfaction

Autores
Meirinhos, G; Goncalves, G; Melo, M; Bessa, M;

Publicação
IEEE ACCESS

Abstract
Virtual Reality (VR) and its capability to replace real stimuli for synthesized ones as if they were real opened several research lines over the years. Many of those consist of trying to validate whether or not VR replicates the same user behaviours seen in reality. In this study, we investigated whether or not product contextualization and gender could influence users' intention to purchase as well as their satisfaction with the application and how presence levels correlate with purchase intention and user satisfaction. The product tested was a double door refrigerator with a touchscreen. We considered two independent variables: Contextualization (Context - The refrigerator was displayed in a kitchen and filled with food products and Neutral - The refrigerator was empty and displayed in an empty room) and gender (male and female). The results indicated that contextualization and gender had no effective impact on purchase intention, user satisfaction with the VR experience nor the sense of presence. A positive correlation was found between presence and user satisfaction. Evidence indicates that it is not necessary to represent products in their context, saving computational power and human resources.

2022

Adaptive Recommendation in Online Environments

Autores
de Azambuja, RX; Morais, AJ; Filipe, V;

Publicação
Distributed Computing and Artificial Intelligence, Volume 2: Special Sessions 18th International Conference, DCAI 2021, Salamanca, Spain, 6-8 October 2021.

Abstract
Recommender systems form a class of Artificial Intelligence systems that aim to recommend relevant items to the users. Due to their utility, it has gained attention in several applications domains and is high demanded for research. In order to obtain successful models in the recommendation problem in non-prohibitive computational time, different heuristics, architectures and information filtering techniques are studied with different datasets. More recently, machine learning, especially through the use of deep learning, has driven growth and expanded the sequential recommender systems development. This research focuses on models for managing sequential recommendation supported by session-based recommendation. This paper presents the characterization in the specific theme and the state-of-the-art towards study object of the thesis: the adaptive recommendation to mitigate the information overload in online environments.

2022

A Review on Computer Vision Technology for Physical Exercise Monitoring

Autores
Khanal, SR; Paulino, D; Sampaio, J; Barroso, J; Reis, A; Filipe, V;

Publicação
ALGORITHMS

Abstract
Physical activity is movement of the body or part of the body to make muscles more active and to lose the energy from the body. Regular physical activity in the daily routine is very important to maintain good physical and mental health. It can be performed at home, a rehabilitation center, gym, etc., with a regular monitoring system. How long and which physical activity is essential for specific people is very important to know because it depends on age, sex, time, people that have specific diseases, etc. Therefore, it is essential to monitor physical activity either at a physical activity center or even at home. Physiological parameter monitoring using contact sensor technology has been practiced for a long time, however, it has a lot of limitations. In the last decades, a lot of inexpensive and accurate non-contact sensors became available on the market that can be used for vital sign monitoring. In this study, the existing research studies related to the non-contact and video-based technologies for various physiological parameters during exercise are reviewed. It covers mainly Heart Rate, Respiratory Rate, Heart Rate Variability, Blood Pressure, etc., using various technologies including PPG, Video analysis using deep learning, etc. This article covers all the technologies using non-contact methods to detect any of the physiological parameters and discusses how technology has been extended over the years. The paper presents some introductory parts of the corresponding topic and state of art review in that area.

2022

Synergistic Use of Sentinel-2 and UAV Multispectral Data to Improve and Optimize Viticulture Management

Autores
Stolarski, O; Fraga, H; Sousa, JJ; Padua, L;

Publicação
DRONES

Abstract
The increasing use of geospatial information from satellites and unmanned aerial vehicles (UAVs) has been contributing to significant growth in the availability of instruments and methodologies for data acquisition and analysis. For better management of vineyards (and most crops), it is crucial to access the spatial-temporal variability. This knowledge throughout the vegetative cycle of any crop is crucial for more efficient management, but in the specific case of viticulture, this knowledge is even more relevant. Some research studies have been carried out in recent years, exploiting the advantage of satellite and UAV data, used individually or in combination, for crop management purposes. However, only a few studies explore the multi-temporal use of these two types of data, isolated or synergistically. This research aims to clearly identify the most suitable data and strategies to be adopted in specific stages of the vineyard phenological cycle. Sentinel-2 data from two vineyard plots, located in the Douro Demarcated Region (Portugal), are compared with UAV multispectral data under three distinct conditions: considering the whole vineyard plot; considering only the grapevine canopy; and considering inter-row areas (excluding all grapevine vegetation). The results show that data from both platforms are able to describe the vineyards' variability throughout the vegetative growth but at different levels of detail. Sentinel-2 data can be used to map vineyard soil variability, whilst the higher spatial resolution of UAV-based data allows diverse types of applications. In conclusion, it should be noted that, depending on the intended use, each type of data, individually, is capable of providing important information for vineyard management.

2022

Smart Systems for Monitoring Buildings - An IoT Application

Autores
Kalbermatter, RB; Brito, T; Braun, J; Pereira, AI; Ferreira, AP; Valente, A; Lima, J;

Publicação
Optimization, Learning Algorithms and Applications - Second International Conference, OL2A 2022, Póvoa de Varzim, Portugal, October 24-25, 2022, Proceedings

Abstract
Life in society has initiated a search for comfort and security in social centers. This search generated revolutions within the knowledge about the technologies involved, making the environments automated and integrated. Along with this increase, ecological concerns have also arisen, which have been involved since the design of intelligent buildings, remaining through the years of their use. Based on these two pillars, the present study aims to monitor three central systems inside the apartments of the Apolo Building (Bragan¸cacity, Portugal). The electrical energy consumption, water flow, and waste disposal systems are integrated through a single database. The data is sent remotely via WiFi through the microcontroller. For better visualization and analytics of the data, a web application is also developed, which allows for real-time monitoring. The obtained results demonstrate to the consumer his behavior regarding household expenses. The idea of showing the consumer their expenditure is to create an ecological awareness. Through the data collected and the environmental alternatives found, it is possible to observe whether there was a behavior change when receiving this data, either in the short or long term.

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