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Publications

2024

Where DoWe Go From Here? Location Prediction from Time-Evolving Markov Models

Authors
Andrade, T; Gama, J;

Publication
39TH ANNUAL ACM SYMPOSIUM ON APPLIED COMPUTING, SAC 2024

Abstract
Various relevant aspects of our lives relate to the places we visit and our daily activities. The movement of individuals between regular places, such as work, school, or other important personal locations is getting increasing attention due to the pervasiveness of geolocation devices and the amount of data they generate. This work presents an approach for location prediction using a probabilistic model and data mining techniques over mobility data streams. We evaluate the method over 5 real-world datasets. The results show the usefulness of the proposal in comparison with other-well-known approaches.

2024

Towards Safer and Efficient Dowry Transactions: A Blockchain-Based Approach

Authors
Bria, MMS; Goncalves, R; Martins, J; Serodio, C; Branco, F;

Publication
GOOD PRACTICES AND NEW PERSPECTIVES IN INFORMATION SYSTEMS AND TECHNOLOGIES, VOL 3, WORLDCIST 2024

Abstract
The dowry payment system is used in the cultural context and tradition of certain financial transactions related to marriages and engagement. However, disputes, fraud, and financial gaps in exploitation occur in these systems, which affect user confidence. This study uses an exploratory approach to identify the main weaknesses of current traditional dowry payment systems and analyses the benefits that blockchain technology and smart contracts can provide. The proposed data security framework combines blockchain security features such as decentralisation, cryptography, and automatic verification through smart contracts to ensure the integrity and reliability of dowry payment transactions. In this study, we adopt the Design Science Research (DSR) methodology to propose producing and developing artefacts that support solving problems in the existing dowry payment system more efficiently. We will disseminate new ideas or concepts developed to indigenous communities in Timor-Leste using the Diffusion of Innovation (DOI) and Technology Acceptance Model (TAM) frameworks to ensure that the technological framework developed can be used safely and efficiently.

2024

Analysis of the Impact of Automation on a Workstation at an Industrial Company Using Simulation

Authors
Costa, C; Ferreira, LP; Ávila, P; Ramos, AL;

Publication
Lecture Notes in Networks and Systems

Abstract
In everyday life, the production lines of companies are required to be flexible, rapidly adopting new processes and methods in order to ensure their competitiveness in the market. The main objective of this study was to analyze the impact of automation on a workstation at an industrial company which paints accessories. By means of simulation, one was able to identify several aspects that negatively affect the company’s overall capacity, namely reduced productivity and long cycle times. The digital tools developed through Visual Basic for Applications constituted the starting point for the automation of several repetitive and bureaucratic tasks which support decision-making, initiating the process of Digital Transformation at the organization. In economic terms, this improvement in the workplace can potentially reduce costs in the order of thousands of euros annually, in addition to increasing productivity thus improving the company’s general performance. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

2024

Evaluating the Impact of Filtering Techniques on Deep Learning-Based Brain Tumour Segmentation

Authors
Rosa, S; Vasconcelos, V; Caridade, PJSB;

Publication
COMPUTERS

Abstract
Gliomas are a common and aggressive kind of brain tumour that is difficult to diagnose due to their infiltrative development, variable clinical presentation, and complex behaviour, making them an important focus in neuro-oncology. Segmentation of brain tumour images is critical for improving diagnosis, prognosis, and treatment options. Manually segmenting brain tumours is time-consuming and challenging. Automatic segmentation algorithms can significantly improve the accuracy and efficiency of tumour identification, thus improving treatment planning and outcomes. Deep learning-based segmentation tumours have shown significant advances in the last few years. This study evaluates the impact of four denoising filters, namely median, Gaussian, anisotropic diffusion, and bilateral, on tumour detection and segmentation. The U-Net architecture is applied for the segmentation of 3064 contrast-enhanced magnetic resonance images from 233 patients diagnosed with meningiomas, gliomas, and pituitary tumours. The results of this work demonstrate that bilateral filtering yields superior outcomes, proving to be a robust and computationally efficient approach in brain tumour segmentation. This method reduces the processing time by 12 epochs, which in turn contributes to lowering greenhouse gas emissions by optimizing computational resources and minimizing energy consumption.

2024

An adequacy theorem between mixed powerdomains and probabilistic concurrency

Authors
Neves, R;

Publication
CoRR

Abstract

2024

Digital Feedback Loop in Paraxial Fluids of Light: A Gate to New Phenomena in Analog Physical Simulations

Authors
Ferreira, TD; Guerreiro, A; Silva, NA;

Publication
PHYSICAL REVIEW LETTERS

Abstract
Easily accessible through tabletop experiments, paraxial fluids of light are emerging as promising platforms for the simulation and exploration of quantumlike phenomena. In particular, the analogy builds on a formal equivalence between the governing model for a Bose-Einstein condensate under the mean-field approximation and the model of laser propagation inside nonlinear optical media under the paraxial approximation. Yet, the fact that the role of time is played by the propagation distance in the analog system imposes strong bounds on the range of accessible phenomena due to the limited length of the nonlinear medium. In this Letter, we present an experimental approach to solve this limitation in the form of a digital feedback loop, which consists of the reconstruction of the optical states at the end of the system followed by their subsequent reinjection exploiting wavefront shaping techniques. The results enclosed demonstrate the potential of this approach to access unprecedented dynamics, paving the way for the observation of novel phenomena in these systems.

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