Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

2025

A Label Propagation Approach for Missing Data Imputation

Authors
Lopes, FL; Mangussi, AD; Pereira, RC; Santos, MS; Abreu, PH; Lorena, AC;

Publication
IEEE ACCESS

Abstract
Missing data is a common challenge in real-world datasets and can arise for various reasons. This has led to the classification of missing data mechanisms as missing completely at random, missing at random, or missing not at random. Currently, the literature offers various algorithms for imputing missing data, each with advantages tailored to specific mechanisms and levels of missingness. This paper introduces a novel approach to missing data imputation using the well-established label propagation algorithm, named Label Propagation for Missing Data Imputation (LPMD). The method combines, weighs, and propagates known feature values to impute missing data. Experiments on benchmark datasets highlight its effectiveness across various missing data scenarios, demonstrating more stable results compared to baseline methods under different missingness mechanisms and levels. The algorithms were evaluated based on processing time, imputation quality (measured by mean absolute error), and impact on classification performance. A variant of the algorithm (LPMD2) generally achieved the fastest processing time compared to other five imputation algorithms from the literature, with speed-ups ranging from 0.7 to 23 times. The results of LPMD were also stable regarding the mean absolute error of the imputed values compared to their original counterparts, for different missing data mechanisms and rates of missing values. In real applications, missingness can behave according to different and unknown mechanisms, so an imputation algorithm that behaves stably for different mechanisms is advantageous. The results regarding ML models produced using the imputed datasets were also comparable to the baselines.

2025

First Twenty Years of the International Symposium on Applied Reconfigurable Computing (ARC): A Selection of Papers

Authors
Cardoso, JMP; Najjar, WA;

Publication
ARC

Abstract
The International Symposium on Applied Reconfigurable Computing (ARC) is an annual forum for the discussion and dissemination of research, notably applying the Reconfigurable Computing (RC) concept to real-world problems. The first edition of ARC took place in 2005, and in 2024, ARC celebrated its 20th edition. During those 20 years, the field of reconfigurable computing saw a tremendous growth in its underlying technology. ARC contributed very significantly to the presentation and dissemination of new ideas, innovative applications, and fruitful discussions, all of which have resulted in the shaping of novel lines of research. Here, we present selected papers from the first 20 years of ARC, that we believe represent the corpus of work and reflect the ARC spirit by covering a broad spectrum of RC applications, benchmarks, tools, and architectures.

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

“O GATO DE BOTAS NA RUA SALDANHA MARINHO”: uma prática de Cidadania Digital no contexto do Paradigma da Educação OnLIFE

Authors
Sitnievski, N; Schlemmer, E;

Publication
Congresso Internacional de Cidadania Digital

Abstract
A evolução das tecnologias digitais e das redes de comunicação favorecem o surgimento de uma sociedade conectada que desafia a educação a ampliar os espaços do ensinar e do aprender para além da fisic

2025

Exploring ChatGPT Efficiency in Automatic Test Generation for Python: A Comparative Analysis

Authors
Guerino, LR; Rizzo Vincenzi, AM;

Publication
SBQS

Abstract
Context: Large language models (LLMs) like ChatGPT have gained attention in automated software testing. This study evaluates ChatGPT-3.5-turbo’s ability to generate test sets for Python programs, comparing it with Pynguin and pre-existing test sets. Problem: Automated testing remains challenging for dynamically typed languages like Python, requiring adaptable tools for diverse code structures. Solution: We assessed ChatGPT-3.5-turbo’s test generation using different prompt configurations and temperature settings. Method: Using 40 Python programs, we generated Pytestcompliant tests via the OpenAI API, varying temperature settings (0.0 to 1.0). Tests were validated using Pytest, with coverage and mutation scores measured via Coverage, MutPy, and Cosmic-Ray. Pynguin-generated and pre-existing test sets served as baselines. Summary of Results: ChatGPT-3.5-turbo successfully generated valid tests for simpler programs, but averaged below 28% overall, with a low cost. Higher temperatures (0.5–1.0) improved results, but combining test cases from all temperatures introduces diversity in the LLM-generated test sets, making it possible to overcome both Pynguin and pre-existing test sets in terms of decision coverage and mutation score.

2025

A Conceptual Framework for AI-based Decision Systems in Critical Infrastructures

Authors
Leyli-Abadi M.; Bessa R.J.; Viebahn J.; Boos D.; Borst C.; Castagna A.; Chavarriaga R.; Hassouna M.; Lemetayer B.; Leto G.; Marot A.; Meddeb M.; Meyer M.; Schiaffonati V.; Schneider M.; Waefler T.; Yagoubi M.;

Publication
Conference Proceedings IEEE International Conference on Systems Man and Cybernetics

Abstract
The interaction between humans and AI in safety-critical systems presents a unique set of challenges that remain partially addressed by existing frameworks. These challenges stem from the complex interplay of requirements for transparency, trust, and explainability, coupled with the necessity for robust and safe decision-making. A framework that holistically integrates human and AI capabilities while addressing these concerns is notably required, bridging the critical gaps in designing, deploying, and maintaining safe and effective systems. This paper proposes a holistic conceptual framework for critical infrastructures by adopting an interdisciplinary approach. It integrates traditionally distinct fields such as mathematics, decision theory, computer science, philosophy, psychology, and cognitive engineering and draws on specialized engineering domains, particularly energy, mobility, and aeronautics. Its flexibility is further demonstrated through a case study on power grid management.

  • 149
  • 4496