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Publications

2026

Discriminant analysis for a folded Watson distribution

Authors
Figueiredo, A; Figueiredo, F;

Publication
JOURNAL OF APPLIED STATISTICS

Abstract
When directional data fall in the positive orthant of the unit hypersphere, a folded directional distribution is preferred over a simple directional distribution for modeling the data. Since directional data, especially axial data, can be modeled using a Watson distribution, this paper considers a folded Watson distribution for such cases. We first address the parameter estimation of this distribution using maximum likelihood, which requires a numerical algorithm to solve the likelihood equations. We use the Expectation-Maximization (EM) algorithm to obtain these estimates and to analyze the properties of the concentration estimator through simulation. Next, we propose the Bayes rule for a folded Watson distribution and evaluate its performance through simulation in various scenarios, comparing it with the Bayes rule for the Watson distribution. Finally, we present examples using both simulated and real data available in the literature.

2026

Adoption of an interactive serious game for developing conflict management skills in international business education

Authors
Almeida, F; Buzady, Z;

Publication
JOURNAL OF INTERNATIONAL EDUCATION IN BUSINESS

Abstract
PurposeThis study aims to examine the use of the serious game FLIGBY to recognize and enhance conflict management skills in international business education. It explores how the game's realistic scenarios and embedded conflict resolution frameworks (i.e. Thomas-Kilmann Instrument, Interest-Based Relational approach and Harvard Negotiation Principles) support the development of key competencies through experiential, gamified learning.Design/methodology/approachThis study analyzes data from 16,597 FLIGBY players using multiple regression models to examine how the game facilitates the recognition of conflict situations and the application of resolution strategies. The risk-free, simulated environment of FLIGBY provides a controlled setting to assess players' conflict management competencies.FindingsThe findings demonstrate that serious games like FLIGBY not only enhance students' understanding of conflict management theories but also actively support the development of practical skills and self-awareness. Players are challenged to analyze interpersonal dynamics, make strategic decisions and reflect on the outcomes of their actions, fostering the development of conflict management skills.Originality/valueThe inclusion of FLIGBY in a business education program has the potential to facilitate experiential learning in conflict management, which is a key topic in international business. Furthermore, it offers data-driven insights into how individuals and teams approach conflict resolutions which may be relevant to refine theoretical models based on gameplay analytics.

2026

GREENTRIBE: An Open-Source Multi-Sensor High-Throughput Plant Phenotyping Framework for Indoor Facilities

Authors
Rodrigues, L; Terra, F; Rodrigues, P; Moura, P; Santos, FNd; Cunha, M;

Publication

Abstract
High-throughput plant phenotyping (HTPP) enhances the throughput, resolution, and dimensionality of conventional manual phenotyping techniques. However, existing platforms face significant challenges, including high acquisition and maintenance costs, limited adaptability to field conditions, and inadequate data management capabilities. This paper introduces GREENTRIBE, an open-source, multi-sensor HTPP architecture that integrates Internet of Things sensing devices and robotics to collect, process, and manage comprehensive phenotypic and environmental data. GREENTRIBE features a multiscale sensing network, built on a sensor-independent communication protocol. An ontology-driven data management layer was designed in accordance with common standards and metadata guidelines, ensuring FAIR (Findable, Accessible, Interoperable, and Reusable) (meta)data. The architecture combines Computer Vision and Artificial Intelligence data analysis pipelines with a process-based crop model for data assimilation, allowing the quantitative traits derived from the sensing layer to be linked to contextual data (genotype, environment, and management conditions). The architecture and performance indicators are presented, demonstrating efficient data collection, processing, and management. Phenotyping is the cornerstone of GREENTRIBE, offering a valuable platform for generating data-rich, reproducible workflows, multimodal datasets, and analysis systems with high impact on Precision Agriculture, improving real-time monitoring, input application, and environmental impacts assessment towards maximized crop productivity, quality, and sustainability.

2026

Comparing Higher Education Rankings with Social Media Posting Strategies

Authors
Rocha, B; Figueira, A;

Publication
SOCIAL NETWORKS ANALYSIS AND MINING, ASONAM 2025, PT III

Abstract
In the competitive landscape of higher education, institutions increasingly rely on international rankings to secure funding, attract talent, and enhance their global reputation. Concurrently, these institutions have expanded their presence on social media, utilizing sophisticated posting strategies not only to disseminate information but also to boost recognition and engagement. This study examines the relationship between the rankings of Higher Education Institutions (HEIs) and their social media posting strategies. We collected and analyzed tweets from 22 HEIs featured in a consolidated ranking system, focusing on various features of their social media posts. The analysis identified six distinct clusters of posting strategies. This paper categorizes the HEIs into these clusters and discusses the implications of differing social media strategies on their rankings The findings suggest a nuanced interaction between social media engagement and the perceived prestige of HEIs.

2026

The Role of Startups in Sustainable Development

Authors
Almeida, F; Okon, E;

Publication
Sustainable Development

Abstract
ABSTRACT The study aims to understand how, to what extent, and through what mechanisms startups contribute to the achievement of the sustainable development goals (SDGs), distinguishing between impact-driven initiatives and approaches in which sustainability is used instrumentally. To this end, a mixed-methods methodology was applied, combining quantitative and qualitative analysis on a sample of 1864 startups accelerated by Y Combinator. The results indicate that the most addressed SDGs are SDG 13 (Climate Action) and SDG 3 (Good Health and Well-being), with an emphasis on clean technologies, low-carbon models, data-based climate monitoring, personalized and preventive medicine, mental health, and clinical data management. In contrast, goals related to biodiversity and reducing inequalities are less represented, revealing gaps and areas with potential for expansion. The study's contributions include identifying patterns and gaps in startups' engagement with the SDGs, reinforcing the importance of public policies and incentives to balance efforts in less addressed areas, and demonstrating the central role of digital technologies and data analysis in promoting sustainability.

2026

Data Leakage Concerns in Training and Evaluation Protocols for Oral Cancer Image Classification

Authors
Nogueira, M; Gomes, EF;

Publication
SN Comput. Sci.

Abstract
Data leakage is a critical issue in deep learning inflating performance and compromise validity, especially in sensitive areas like medical imaging. This study systematically evaluates two common leakage types in oral squamous cell carcinoma classification from histopathology images: (1) preprocessing leakage (global normalization before dataset splitting) and (2) a severe sample-related (patient-related) contamination scenario created by mixing closely related original and augmented images across splits. We trained 11 CNN and Transformer-based models on a public oral cancer histopathology dataset, benchmarking results against published leakage-free baselines. The results obtained show that the configuration with random splitting of original and augmented images (Scenario 2) artificially increased accuracy by up to 18% (mean +14.3%) compared to leakage-free conditions, while the preprocessing-based leakage (Scenario 1) showed smaller deviations (+1.8%). These inflated metrics arise from a combination of cross-split contamination between closely related samples and increased dataset redundancy, rather than genuine gains in generalization ability. Transformers improved leak-free accuracy (+3.9%) but degraded performance in Scenario 2 (-1.4%), revealing sensitivity to sample-specific biases. The observed performance gains under data leakage conditions are methodological artifacts that undermine clinical reliability, with a severe sample-related contamination scenario (Scenario 2) with random splitting of original and augmented images being particularly detrimental due to its promotion of non-generalizable feature learning. The quantitative benchmarks established here-including a mean accuracy gap of 12.5% (Scenario 2 vs. Scenario 1) across 11 models and Transformer architectures’ sensitivity to contamination-reveal fundamental tradeoffs between metric inflation and model trustworthiness. These findings establish quantitative benchmarks for leakage impacts in medical imaging and inform future guidelines for trustworthy AI development in pathology. © The Author(s) 2026.

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