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Publications

2024

Computing Motifs in Hypergraphs

Authors
Nóbrega, D; Ribeiro, P;

Publication
COMPLEX NETWORKS XV, COMPLENET 2024

Abstract
Motifs are overrepresented and statistically significant sub-patterns in a network, whose identification is relevant to uncover its underlying functional units. Recently, its extraction has been performed on higher-order networks, but due to the complexity arising from polyadic interactions, and the similarity with known computationally hard problems, its practical application is limited. Our main contribution is a novel approach for hyper-subgraph census and higher-order motif discovery, allowing for motifs with sizes 3 or 4 to be found efficiently, in real-world scenarios. It is consistently an order of magnitude faster than a baseline state-of-art method, while using less memory and supporting a wider range of base algorithms.

2024

Control of a Mobile Robot Through VDA5050 Standard

Authors
Brilhante, M; Rebelo, PM; Oliveira, PM; Sobreira, H; Costa, P;

Publication
ROBOT 2023: SIXTH IBERIAN ROBOTICS CONFERENCE ADVANCES IN ROBOTICS, VOL 1

Abstract
Since creating universally capable robots is challenging for a single manufacturer, a diverse fleet of robots from various manufacturers is utilized. However, these heterogeneous fleets encounter communication and interoperability issues. As a result, there is a growing need for a standardized interface that is capable of communicating, controlling and managing a diverse fleet without these interoperability issues. This paper presents a translation software module capable of controlling an autonomous mobile robot and communicating with a ROS-based robot fleet manager using the VDA5050 Standard and exchanging information via the MQTT communication protocol, aiming at flexibility and control across different robot brands. The effectiveness of the software in controlling a mobile robot via the VDA5050 standard was demonstrated by the results. It accurately analysed data from the Robot Fleet Manager, converted it into VDA 5050 JSON messages and skilfully translated it back into ROS messages. The robot's behavior remained consistent before and after the VDA5050 implementation.

2024

<i>HiClass4MD</i>: a Hierarchical Classifier for Transportation Mode Detection

Authors
Muhammad, AR; Aguiar, A; Mendes Moreira, J;

Publication
2024 IEEE 27TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS, ITSC

Abstract
Accurate identification of transportation mode distribution is essential for effective urban planning. Recent advancements in machine learning have spurred research on automated Transportation Mode Detection (TMD). While existing TMD methods predominantly employ standard flat classification methods, this paper introduces HiClass4MD, a novel hierarchical approach. By leveraging the misclassification errors from standard flat classifier, HiClass4MD learns the class hierarchy for transportation modes. Although hierarchical metrics initially indicated performance improvements when applied to real-world GPS trajectories dataset, a subsequent evaluation using conventional metrics revealed inconsistent results. While decision trees benefited marginally, other classifiers exhibited no significant gains or even degraded. This study highlights the complexity of applying hierarchical classification to TMD and underscores the need for further investigation into the factors influencing its effectiveness.

2024

Forest Fire Risk Prediction Using Machine Learning

Authors
Vilaças Nogueira, JD; Solteiro Pires, EJ; Reis, A; Moura Oliveira, PBd; Pereira, A; Barroso, J;

Publication
SOCO (2)

Abstract
With the serious danger to nature and humanity that forest fires are, taken into consideration, this work aims to develop an artificial intelligence model capable of accurately predicting the forest fire risk in a certain region based on four different factors: temperature, wind speed, rain and humidity. Thus, three models were created using three different approaches: Artificial Neural Networks (ANN), Random Forest (RF), and K-Nearest Neighbor (KNN), and making use of an Algerian forest fire dataset. The ANN and RF both achieved high accuracy results of 97%, while the KNN achieved a slightly lower average of 91%.

2024

Does financial knowledge decline with age? An analysis of small enterprise managers in Spain

Authors
Álvarez Espiño, M; Fernández López, S; Rey Ares, L; Almeida, FL;

Publication
New Practices for Entrepreneurship Innovation

Abstract
Small enterprises (SEs) represent the majority of the businesses worldwide, playing a leading role in job creation and economic development. The success of these firms substantially depends on the financial knowledge of their owners/managers. Previous literature in the field of household finances has indicated that financial literacy declines as individual ages. However, the scarce literature on entrepreneurs' financial literacy has not addressed this issue. Using a sample of 896 SE owners/managers, drawn from the survey of small enterprises' financial literacy in Spain, the authors observe a decline in objective financial knowledge with age through multivariate analyses using probit and ordered probit models. The lack of financial knowledge may put at risk the economic feasibility of an SE. Therefore, it is essential to design financial education mechanisms that are sensitive to the needs of SE owners/managers at different stages of their working lives. © 2024 by IGI Global. All rights reserved.

2024

Databases in Edge and Fog Environments: A Survey

Authors
Ferreira, LMM; Coelho, F; Pereira, J;

Publication
ACM COMPUTING SURVEYS

Abstract
While a significant number of databases are deployed in cloud environments, pushing part or all data storage and querying planes closer to their sources (i.e., to the edge) can provide advantages in latency, connectivity, privacy, energy, and scalability. This article dissects the advantages provided by databases in edge and fog environments by surveying application domains and discussing the key drivers for pushing database systems to the edge. At the same time, it also identifies the main challenges faced by developers in this new environment and analyzes the mechanisms employed to deal with them. By providing an overview of the current state of edge and fog databases, this survey provides valuable insights into future research directions.

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