2024
Authors
Teixeira, B; Pinto, G; Filipe, V; Teixeira, A;
Publication
COMPUTATIONAL SCIENCE AND ITS APPLICATIONS-ICCSA 2024 WORKSHOPS, PT II
Abstract
This article conducts a comprehensive review of the existing literature on data augmentation and data generation techniques within the context of medical image processing. Addressing the challenges associated with building sizable medical image datasets, including the rarity of certain medical conditions, patient privacy concerns, the need for expert labeling, and the associated expenses, this review focuses on methodologies aimed at enhancing the volume and diversity of available data. Special emphasis is placed on techniques such as data augmentation and data generation, with a particular interest in their application to medical image datasets. The objective is to provide a synthesis of current research, methodologies, and advancements in this domain, offering insights into the state-of-the-art practices and identifying potential avenues for future developments in medical image data augmentation.
2024
Authors
Elsaid, M; Inacio, SI; Salgado, HM; Pessoa, LM;
Publication
2024 INTERNATIONAL CONFERENCE ON ELECTROMAGNETICS IN ADVANCED APPLICATIONS, ICEAA 2024
Abstract
The Sub-THz and millimeter-wave bands have gained popularity, with the expectation that they will host the next generation of wireless communication systems. Furthermore, research on beam-steering characteristics provided by Programmable Electromagnetic Surfaces, such as Reflective Intelligent Surfaces (RISs), has garnered considerable attention as an enabling technology for 6G communications. Due to size limitations, RISs face challenges related to power consumption in the reconfigurable elements and their integration with unit cells operating at high frequencies. This paper discusses the design of a 1-bit reconfigurable unit cell at the D-band using non-volatile technology to minimize static power consumption. Simulation results show that the proposed unit cell performs well with a reflection loss of less than 1.3 dB in both reconfigurable states across a frequency band from 120 to 170 GHz. Moreover, the phase difference between the two states is maintained at 180 degrees +/- 20 degrees, with an operational bandwidth of approximately 16 GHz. The beamforming capabilities, with steering angles from -60 degrees to 60 degrees, of the 12x12 RIS, utilizing the proposed unit cell, have been demonstrated in terms of controlling the main beam radiation precisely to various angles with consistent performance at frequencies of 147GHz,152GHz, and 152.5 GHz.
2024
Authors
Felgueiras, F; Mourao, Z; Moreira, A; Gabriel, MF;
Publication
SUSTAINABILITY
Abstract
Office workers spend a considerable part of their day at the workplace, making it vital to ensure proper indoor environmental quality (IEQ) conditions in office buildings. This work aimed to identify significant factors influencing IEQ and assess the effectiveness of an environmental intervention program, which included the introduction of indoor plants, carbon dioxide (CO2) sensors, ventilation, and printer relocation (source control), in six modern office buildings in improving IEQ. Thirty office spaces in Porto, Portugal, were randomly divided into intervention and control groups. Indoor air quality, thermal comfort, illuminance, and noise were monitored before and after a 14-day intervention implementation. Occupancy, natural ventilation, floor type, and cleaning time significantly influenced IEQ levels. Biophilic interventions appeared to decrease volatile organic compound concentrations by 30%. Installing CO2 sensors and optimizing ventilation strategies in an office that mainly relies on natural ventilation effectively improved air renewal and resulted in a 28% decrease in CO2 levels. The implementation of a source control intervention led to a decrease in ultrafine particle and ozone concentrations by 14% and 85%, respectively. However, an unexpected increase in airborne particle levels was detected. Overall, for a sample of offices that presented acceptable IEQ levels, the intervention program had only minor or inconsistent impacts. Offices with declared IEQ problems are prime candidates for further research to fully understand the potential of environmental interventions.
2024
Authors
Teixeira, R; Cerveira, A; Pires, EJS; Baptista, J;
Publication
APPLIED SCIENCES-BASEL
Abstract
Several sectors, such as agriculture and renewable energy systems, rely heavily on weather variables that are characterized by intermittent patterns. Many studies use regression and deep learning methods for weather forecasting to deal with this variability. This research employs regression models to estimate missing historical data and three different time horizons, incorporating long short-term memory (LSTM) to forecast short- to medium-term weather conditions at Quinta de Santa B & aacute;rbara in the Douro region. Additionally, a genetic algorithm (GA) is used to optimize the LSTM hyperparameters. The results obtained show that the proposed optimized LSTM effectively reduced the evaluation metrics across different time horizons. The obtained results underscore the importance of accurate weather forecasting in making important decisions in various sectors.
2024
Authors
Mendes, J; Lima, SR; Carvalho, P; Silva, JMC;
Publication
INFORMATION SYSTEMS AND TECHNOLOGIES, VOL 1, WORLDCIST 2023
Abstract
Network traffic sampling is an effective method for understanding the behavior and dynamics of a network, being essential to assist network planning and management. Tasks such as controlling Service Level Agreements or Quality of Service, as well as planning the capacity and the safety of a network can benefit from traffic sampling advantages. The main objective of this paper is focused on evaluating the impact of sampling network traffic on: (i) achieving a low-overhead estimation of the network state and (ii) assessing the statistical properties that sampled network traffic presents regarding the eventual persistence of LongRange Dependence (LRD). For that, different Hurst parameter estimators have been used. Facing the impact of LRD on network congestion and traffic engineering, this work will help clarify the suitability of distinct sampling techniques in accurate network analysis.
2024
Authors
Torres, AI; Paulo, DLS; Santos, JD; Pires, PB;
Publication
Leveraging AI for Effective Digital Relationship Marketing
Abstract
This chapter aims to discuss about the potential Return on Investment (ROI) measures from Artificial intelligence (AI) investments that business can leverage. It discusses the concepts and describes the dimensions, features and tools of AI investments in Marketing business, to assist the readers to understand about the topic. The authors also describe the major drivers of ROI measures for business applications and discusses the concerns and limitations of tangible measures. So, this document contributes to the literature on ROI (in)tangibles measures that leverage AI investments and features issues in digital marketing, at large and potentially offers a theoretical grounding for many empirical and theoretical future studies. © 2025 by IGI Global Scientific Publishing. All rights reserved.
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