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Publicações

2023

A Machine Learning Approach for Predicting Microsatellite Instability using RNA-seq

Autores
Simões, M; Pereira, T; Silva, F; Machado, JMF; Oliveira, HP;

Publicação
BIBM

Abstract
Microsatellite Instability (MSI) is an important biomarker in cancer patients, showing a defective DNA mismatch repair system. Its detection allows the use of immunotherapy to treat cancer, an approach that is revolutionizing cancer treatment. MSI is especially relevant for three types of cancer: Colon Adenocarcinoma (COAD), Stomach Adenocarcinoma (STAD), and Uterus corpus endometrial cancer (UCEC). In this work, learning algorithms were employed to predict MSI using RNA-seq data from The Cancer Genome Atlas (TCGA) database, with a focus on the selection of the most informative genomic features. The Multi-Layer Perceptron (MLP) obtained the best score (AUC = 98.44%), showing that it is possible to exploit information from RNA-seq data to find relevant relationships with the instability levels of microsatellites (MS). The accurate prediction of MSI with transcription data from cancer patients will help with the correct determination of MSI status and adequate prescription of immunotherapy, creating more precise and personalized patient care. At the genetic level, the study revealed a high expression of genes related to cell regulation functions, and a low expression of genes responsible for Mismatch Repair functions, in patients with high instability.

2023

Enhancing Grape Brix Prediction in Precision Viticulture: A Benchmarking Study of Predictive Models using Hyperspectral Proximal Sensors

Autores
Santos-Campos, M; Tosin, R; Rodrigues, L; Gonçalves, I; Barbosa, C; Martins, R; Santos, F; Cunha, M;

Publicação
The 3rd International Electronic Conference on Agronomy

Abstract

2023

The role of human capital, structural change, and institutional quality on Brazil's economic growth over the last two hundred years (1822-2019)

Autores
Dore, NI; Teixeira, AAC;

Publicação
STRUCTURAL CHANGE AND ECONOMIC DYNAMICS

Abstract
A growing body of empirical literature has considered very long-time horizons when studying the sources of a country's economic growth. Nevertheless, the growth experiences of emerging economies (EEs) have been overlooked. This study examines to what extent human capital, structural change, and institutional quality contribute to the economic growth of one of the largest EEs in the world, Brazil, between 1822 and 2019. Resorting to the ARDL cointegration technique, the results suggest that years of schooling (human capital) have a positive and long-lasting impact on Brazil's economic growth. Moreover, there is solid evidence that sectoral changes toward more advanced and sophisticated manufacturing basis is growth-enhancing in the country. Finally, institutional quality does not constitute over the very long-run, a significant booster of Brazilian economic growth.

2023

Applying Machine Learning to Estimate the Effort and Duration of Individual Tasks in Software Projects

Autores
Sousa, AO; Veloso, DT; Gonçalves, HM; Faria, JP; Mendes Moreira, J; Graça, R; Gomes, D; Castro, RN; Henriques, PC;

Publicação
IEEE ACCESS

Abstract
Software estimation is a vital yet challenging project management activity. Various methods, from empirical to algorithmic, have been developed to fit different development contexts, from plan-driven to agile. Recently, machine learning techniques have shown potential in this realm but are still underexplored, especially for individual task estimation. We investigate the use of machine learning techniques in predicting task effort and duration in software projects to assess their applicability and effectiveness in production environments, identify the best-performing algorithms, and pinpoint key input variables (features) for predictions. We conducted experiments with datasets of various sizes and structures exported from three project management tools used by partner companies. For each dataset, we trained regression models for predicting the effort and duration of individual tasks using eight machine learning algorithms. The models were validated using k-fold cross-validation and evaluated with several metrics. Ensemble algorithms like Random Forest, Extra Trees Regressor, and XGBoost consistently outperformed non-ensemble ones across the three datasets. However, the estimation accuracy and feature importance varied significantly across datasets, with a Mean Magnitude of Relative Error (MMRE) ranging from 0.11 to 9.45 across the datasets and target variables. Nevertheless, even in the worst-performing dataset, effort estimates aggregated to the project level showed good accuracy, with MMRE = 0.23. Machine learning algorithms, especially ensemble ones, seem to be a viable option for estimating the effort and duration of individual tasks in software projects. However, the quality of the estimates and the relevant features may depend largely on the characteristics of the available datasets and underlying projects. Nevertheless, even when the accuracy of individual estimates is poor, the aggregated estimates at the project level may present a good accuracy due to error compensation.

2023

Investigating the reviewer assignment problem: A systematic literature review

Autores
Ribeiro, AC; Sizo, A; Reis, LP;

Publicação
JOURNAL OF INFORMATION SCIENCE

Abstract
The assignment of appropriate reviewers to academic articles, known as the reviewer assignment problem (RAP), has become a crucial issue in academia. While there has been much research on RAP, there has not yet been a systematic literature review (SLR) examining the various approaches, techniques, algorithms and discoveries related to this topic. To conduct the SLR, we identified and evaluated relevant articles from four databases using defined inclusion and exclusion criteria. We analysed the selected articles and extracted information, and assessed their quality. Our review identified 67 articles on RAP published in conferences and journals up to mid-2022. As one of the main challenges in RAP is acquiring open data, we have studied the data sources used by researchers and found that most studies use real data from conferences, bibliographic databases and online academic search engines. RAP is divided into two main phases: (1) finding/recommending expert reviewers and (2) assigning reviewers to submitted manuscripts. In Phase 1, we have identified that decision support systems, recommendation systems, and machine learning-oriented approaches are more commonly used due to better results. In Phase 2, heuristics and metaheuristics are the approaches that present better results and are consequently more commonly used by researchers. Based on the analysed studies, we have identified potential areas for future research that could lead to improved results. Specifically, we suggest exploring the application of deep neural networks for calculating the degree of correspondence and using the Boolean satisfiability problem to optimise the attribution process.

2023

Improved hybridization of CEVESA MIBEL market model based on real market data

Autores
de Oliveira, AR; Collado, JV; Saraiva, JT; Campos, FA;

Publicação
2023 19TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET, EEM

Abstract
This paper presents a new hybridization approach to improve CEVESA, a multi-zonal hydro-thermal equilibrium model for the joint dispatch of energy and secondary reserve capacity for the Iberian Electricity Market (MIBEL). Like similar fundamental models, CEVESA provides market prices that typically show an average systematic bias compared to real market prices. This is because these models do not always capture the true variable production costs of the generation units or the additional markups that generation companies may include in their pricing strategy. Based on real market outcomes, this paper proposes a new methodology built on a previous hybridization approach that estimated a constant monthly markup per thermal offering unit [1]. This new methodology is based on a functional estimation of the offering unit cost (or bidding price), using as input the initial CEVESA production costs based on the fuel and emissions commodities' prices, correcting the power plants' markup.

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