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Publicações

2024

UAV-Assisted Navigation for Insect Traps in Olive Groves

Autores
Berger, GS; Bonzatto, L Jr; Pinto, MF; Júnior, AO; Mendes, J; da Silva, YMR; Pereira, AI; Valente, A; Lima, J;

Publicação
ROBOT 2023: SIXTH IBERIAN ROBOTICS CONFERENCE, VOL 2

Abstract
Unmanned Aerial Vehicles (UAVs) have emerged as valuable tools in precision agriculture due to their ability to provide timely and detailed information over large agricultural areas. In this sense, this work aims to evaluate the semi-autonomous navigation capacity of a multirotor UAV when applied in the field of precision agriculture. For this, a small aircraft is used to identify and track a set of fiducial markers (Ar Track Alvar) in an environment that simulates inspections of insect traps in olive groves. The purpose of this marker is to provide a visual reference point for the drone's navigation system. Once the Ar Track Alvar marker is detected, the robot will receive navigation information based on the marker's position to approach the specific trap. The experimental setup evaluated the computer vision algorithm applied to the UAV to make it recognize the Ar Track Alvar marker and then reach the trap efficiently. Experimental tests were conducted in a indoor and outdoor environment using DJI Tello. The results demonstrated the feasibility of applying these fiducial markers as a solution for the UAV's navigation in this proposed scenario.

2024

The moderator effect of balance of power on the relationships between the adoption of digital technologies in supply chain management processes and innovation performance in SMEs

Autores
Zimmermann, R; Soares, A; Roca, JB;

Publicação
INDUSTRIAL MARKETING MANAGEMENT

Abstract
Managing supply chain (SC) relationships to deal with challenges posed by contemporary social and business environments is a difficult task that can be facilitated with the use of digital technologies. The growing complexity of supply chains, characterized by over-dependencies on geographically dispersed partners across different regions, increases risks related to managing these relationships and highlights the importance of collaboration and balancing the power dynamics between SC partners. Previous studies have shown that small and medium enterprises (SMEs) can be considered the weakest link in terms of digitization and balance of power. This article aims to analyse how buyer-seller power relations moderate the relationship between the adoption of digital technologies in supply chain management (SCM) processes and innovation performance in the context of SMEs. Data were collected from manufacturing SMEs operating in Portugal. The results support the assumption that the use of digital technologies in processes related to SCM has a positive effect on SMEs innovation performance. The results also suggest that non-mediated power and reward-mediated positively moderate the relationship between the adoption of digital technologies and innovation performance, while the impact of coercive-mediated power was not confirmed. The article contributes to theory and practice by advancing the literature and guiding managers in the challenging task of carrying out digital transformation initiatives, considering their relationship with the power dynamics in the complex context of SMEs.

2024

S plus t-SNE - Bringing Dimensionality Reduction to Data Streams

Autores
Vieira, PC; Montrezol, JP; Vieira, JT; Gama, J;

Publicação
ADVANCES IN INTELLIGENT DATA ANALYSIS XXII, PT II, IDA 2024

Abstract
We present S+t-SNE, an adaptation of the t-SNE algorithm designed to handle infinite data streams. The core idea behind S+t-SNE is to update the t-SNE embedding incrementally as new data arrives, ensuring scalability and adaptability to handle streaming scenarios. By selecting the most important points at each step, the algorithm ensures scalability while keeping informative visualisations. By employing a blind method for drift management, the algorithm adjusts the embedding space, which facilitates the visualisation of evolving data dynamics. Our experimental evaluations demonstrate the effectiveness and efficiency of S+t-SNE, whilst highlighting its ability to capture patterns in a streaming scenario. We hope our approach offers researchers and practitioners a real-time tool for understanding and interpreting high-dimensional data.

2024

Students' complex trajectories: exploring degree change and time to degree

Autores
Pêgo, JP; Miguéis, VL; Soeiro, A;

Publicação
INTERNATIONAL JOURNAL OF EDUCATIONAL TECHNOLOGY IN HIGHER EDUCATION

Abstract
The complex trajectories of higher education students are deviations from the regular path due to delays in completing a degree, dropping out, taking breaks, or changing programmes. In this study, we investigated degree changing as a cause of complex student trajectories. We characterised cohorts of students who graduated with a complex trajectory and identified the characteristics that influenced the time to graduation. To support this predictive task, we employed machine learning techniques such as neural networks, support vector machines, and random forests. In addition, we used interpretable techniques such as decision trees to derive managerial insights that could prove useful to decision-makers. We validated the proposed methodology taking the University of Porto (Portugal) as case study. The results show that the time to degree (TTD) of students with and without complex trajectories was different. Moreover, the proposed models effectively predicted TTD, outperforming two benchmark models. The random forest model proved to be the best predictor. Finally, this study shows that the factors that best predict TTD are the median TTD and the admission regime of the programme of destination of transfer students, followed by the admission average of the previous programme. By identifying students who take longer to complete their studies, targeted interventions such as counselling and tutoring can be promoted, potentially improving completion rates and educational outcomes without having to use as many resources.

2024

Network-based Approach for Stopwords Detection

Autores
António Ali, FDM; Jesus, Gd; Cardoso, HL; Nunes, SS; Silva, RS;

Publicação
Proceedings of the 16th International Conference on Computational Processing of Portuguese, PROPOR 2024, Santiago de Compostela, Galicia/Spain, March 12-15, 2024, Volume 2

Abstract

2024

Prediction of Electric Power Generation for Green Mobility Vehicles

Autores
Teixeira, B; Pinto, T; Catarino, P; Vasco, P; Soares, J; Reis, A; Barroso, J;

Publicação
2024 22ND INTERNATIONAL CONFERENCE ON INTELLIGENT SYSTEMS APPLICATIONS TO POWER SYSTEMS, ISAP 2024

Abstract
With the increasing adoption of electric motorcycles in urban environments, efficient energy management becomes essential to maximize the autonomy and sustainability of these vehicles. This study proposes the development of forecasting models to predict energy consumption and generation as means to optimize the charging of electric motorcycle batteries. Three models are explored in this work, namely multiple linear regression, LSTM (Long Short-Term Memory) neural networks, and XGBoost (Extreme Gradient Boosting). The performance of each model is assessed through various metrics. The results indicate that the LSTM model exhibited the best performance, particularly in identifying complex temporal patterns in solar radiation data. However, XGBoost also proved to be reasonable, while multiple linear regression was less satisfactory. The study discusses its limitations, such as the lack of deep refinement of model parameters, and future perspectives, including the exploration of other models and the implementation of strategies for predictive battery charging management.

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