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Publications

2025

A New Closed-Loop Control Paradigm Based on Process Moments

Authors
Vrancic, D; Bisták, P; Huba, M; Oliveira, PM;

Publication
MATHEMATICS

Abstract
The paper presents a new control concept based on the process moment instead of the process states or the process output signal. The control scheme is based on separate control of reference tracking and disturbance rejection. The tracking control is achieved by additionally feeding the input of the process model by the scaled output signal of the process model. The advantage of such feedback is that the final state of the process output can be analytically calculated and used for control instead of the actual process output value. The disturbance rejection, including model imperfections, is controlled by feeding back the filtered difference between the process output and the model output to the process input. The performance of tracking and disturbance rejection is simply controlled by two user-defined gains. Several examples have shown that the new control method provides very good and stable tracking and disturbance rejection performance.

2025

Histopoly: A serious game for teaching histology to 1st year veterinary students

Authors
Marcos, R; Gomes, A; Santos, M; Coelho, A;

Publication
ANATOMICAL SCIENCES EDUCATION

Abstract
Histology is a preclinical subject transversal in medical, dental, and veterinary curricula. Classical teaching approaches in histology are often undermined by lower motivation and engagement of students, which may be addressed by innovative learning environments. Herein, we developed a serious game approach and compared it with a classical teaching style. The students' feedback was evaluated by questionnaires, and their performance on quizzes and exam's scores were assessed. The serious game (Histopoly) consisted of a game-based web application for the teacher/game master, a digital gaming application used by the students as a controller, and a projected digital board game. The board featured rows for the four fundamental tissues (epithelial, connective, muscular, and nervous) paired with question tiles and additional tiles with more demanding activities (e.g., drawing, presenting slides, and making a syllabus). Participants included all veterinary students enrolled in the first year. Paired laboratory sessions were split with four sections (n = 94 students) playing Histopoly at the end of all sessions and two sections (n = 28 students) completing small evaluations every three weeks at the beginning of sessions. According to the questionnaires, students that played the serious game were more motivated, engaged, and more interconnected with classmates. The activity was considered fun, and students enjoyed the classes more. No differences in the final examination scores were found, but the percentage of correct answers provided throughout the serious game was significantly higher. Overall, these findings argue for the inclusion of serious games in modern histology teaching to promote student engagement in learning.

2025

Augmented Reality in Information Design

Authors
Fadel, LM; Coelho, A;

Publication
Springer Series in Design and Innovation

Abstract
The potential of Augmented Reality (AR) has been harnessed to create immersive game settings, present layers of relevant information in museums, streamline procedures in healthcare and industry, and captivate consumers through innovative marketing strategies. Certain artifacts lend themselves well to representation in AR, especially those requiring a seamless fusion of the information layer with physical space. This integration underscores the suitability of information design artifacts for AR implementation. This study aims to delineate the distinctive attributes of AR in remediating information design, effectively catering to the user’s informational needs. To this end, we analyzed the Google Translate app, examining it through the analytical lens of body schema and haptic engagement. The findings reveal that AR manifests as a performative, personalized, crafted image that fosters involvement through agency. The performative nature of the image directs attention, while individual images collectively form a collection. It is recommended that AR design be centered around achieving harmony among body, media, and space. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.

2025

Evaluation of PID-Based Algorithms for UGVs

Authors
Gameiro, T; Pereira, T; Moghadaspoura, H; Di Giorgio, F; Viegas, C; Ferreira, N; Ferreira, J; Soares, S; Valente, A;

Publication
Algorithms

Abstract
The autonomous navigation of unmanned ground vehicles (UGVs) in unstructured environments, such as agricultural or forestry settings, has been the subject of extensive research by various investigators. The navigation capability of a UGV in unstructured environments requires considering numerous factors, including the quality of data reception that allows reliable interpretation of what the UGV perceives in a given environment, as well as the use these data to control the UGV’s navigation. This article aims to study different PID control algorithms to enable autonomous navigation on a robotic platform. The robotic platform consists of a forestry tractor, used for forest cleaning tasks, which was converted into a UGV through the integration of sensors. Using sensor data, the UGV’s position and orientation are obtained and utilized for navigation by inputting these data into a PID control algorithm. The correct choice of PID control algorithm involved the study, analysis, and implementation of different controllers, leading to the conclusion that the Vector Field control algorithm demonstrated better performance compared to the others studied and implemented in this paper.

2025

Approaches to Conflict-free Replicated Data Types

Authors
Almeida, PS;

Publication
ACM COMPUTING SURVEYS

Abstract
Conflict-free Replicated Data Types (CRDTs) allow optimistic replication in a principled way. Different replicas can proceed independently, being available even under network partitions and always converging deterministically: Replicas that have received the same updates will have equivalent state, even if received in different orders. After a historical tour of the evolution from sequential data types to CRDTs, we present in detail the two main approaches to CRDTs, operation-based and state-based, including two important variations, the pure operation-based and the delta-state based. Intended for prospective CRDT researchers and designers, this article provides solid coverage of the essential concepts, clarifying some misconceptions that frequently occur, but also presents some novel insights gained from considerable experience in designing both specific CRDTs and approaches to CRDTs.

2025

GANs in the Panorama of Synthetic Data Generation Methods

Authors
Vaz, B; Figueira, A;

Publication
ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS

Abstract
This article focuses on the creation and evaluation of synthetic data to address the challenges of imbalanced datasets in machine learning (ML) applications, using fake news detection as a case study. We conducted a thorough literature review on generative adversarial networks (GANs) for tabular data, synthetic data generation methods, and synthetic data quality assessment. By augmenting a public news dataset with synthetic data generated by different GAN architectures, we demonstrate the potential of synthetic data to improve ML models' performance in fake news detection. Our results show a significant improvement in classification performance, especially in the underrepresented class. We also modify and extend a data usage approach to evaluate the quality of synthetic data and investigate the relationship between synthetic data quality and data augmentation performance in classification tasks. We found a positive correlation between synthetic data quality and performance in the underrepresented class, highlighting the importance of high-quality synthetic data for effective data augmentation.

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