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Publicações

Publicações por LIAAD

2017

Reutilization of Clinical Data for Research: The Footprint Scientific Model of the Hospital Center of Sao Joao

Autores
Guimaraes, R; Dinis Oliveira, RJ; Pereira, A; Rodrigues, P; Santos, A;

Publicação
ACTA MEDICA PORTUGUESA

Abstract
N/A.

2017

Development and Validation of Risk Matrices for Crohn's Disease Outcomes in Patients Who Underwent Early Therapeutic Interventions

Autores
Dias, CC; Rodrigues, PP; Coelho, R; Santos, PM; Fernandes, S; Lago, P; Caetano, C; Rodrigues, Â; Portela, F; Oliveira, A; Ministro, P; Cancela, E; Vieira, AI; Barosa, R; Cotter, J; Carvalho, P; Cremers, I; Trabulo, D; Caldeira, P; Antunes, A; Rosa, I; Moleiro, J; Peixe, P; Herculano, R; Gonçalves, R; Gonçalves, B; Sousa, HT; Contente, L; Morna, H; Lopes, S; Magro, F; on behalf GEDII,;

Publicação
JOURNAL OF CROHNS & COLITIS

Abstract
Introduction: The establishment of prognostic models for Crohn's disease [CD] is highly desirable, as they have the potential to guide physicians in the decision-making process concerning therapeutic choices, thus improving patients' health and quality of life. Our aim was to derive models for disabling CD and reoperation based solely on clinical/demographic data. Methods: A multicentric and retrospectively enrolled cohort of CD patients, subject to early surgery or immunosuppression, was analysed in order to build Bayesian network models and risk matrices. The final results were validated internally and with a multicentric and prospectively enrolled cohort. Results: The derivation cohort included a total of 489 CD patients [64% with disabling disease and 18% who needed reoperation], while the validation cohort included 129 CD patients with similar outcome proportions. The Bayesian models achieved an area under the curve of 78% for disabling disease and 86% for reoperation. Age at diagnosis, perianal disease, disease aggressiveness and early therapeutic decisions were found to be significant factors, and were used to construct user-friendly matrices depicting the probability of each outcome in patients with various combinations of these factors. The matrices exhibit good performance for the most important criteria: disabling disease positive post-test odds = 8.00 [2.72-23.44] and reoperation negative post-test odds = 0.02 [0.00-0.11]. Conclusions: Clinical and demographical risk factors for disabling CD and reoperation were determined and their impact was quantified by means of risk matrices, which are applicable as bedside clinical tools that can help physicians during therapeutic decisions in early disease management.

2017

30th IEEE International Symposium on Computer-Based Medical Systems, CBMS 2017, Thessaloniki, Greece, June 22-24, 2017

Autores
Bamidis, PD; Konstantinidis, ST; Rodrigues, PP;

Publicação
CBMS

Abstract

2017

Combining Feature and Algorithm Hyperparameter Selection using some Metalearning Methods

Autores
Cachada, M; Abdulrahman, SM; Brazdil, P;

Publicação
Proceedings of the International Workshop on Automatic Selection, Configuration and Composition of Machine Learning Algorithms co-located with the European Conference on Machine Learning & Principles and Practice of Knowledge Discovery in Databases, AutoML@PKDD/ECML 2017, Skopje, Macedonia, September 22, 2017.

Abstract
Machine learning users need methods that can help them identify algorithms or even workflows (combination of algorithms with preprocessing tasks, using or not hyperparameter configurations that are different from the defaults), that achieve the potentially best performance. Our study was oriented towards average ranking (AR), an algorithm selection method that exploits meta-data obtained on prior datasets. We focused on extending the use of a variant of AR* that takes A3R as the relevant metric (combining accuracy and run time). The extension is made at the level of diversity of the portfolio of workflows that is made available to AR. Our aim was to establish whether feature selection and different hyperparameter configurations improve the process of identifying a good solution. To evaluate our proposal we have carried out extensive experiments in a leave-one-out mode. The results show that AR* was able to select workflows that are likely to lead to good results, especially when the portfolio is diverse. We additionally performed a comparison of AR* with Auto-WEKA, running with different time budgets. Our proposed method shows some advantage over Auto-WEKA, particularly when the time budgets are small.

2017

Proceedings of the International Workshop on Automatic Selection, Configuration and Composition of Machine Learning Algorithms co-located with the European Conference on Machine Learning & Principles and Practice of Knowledge Discovery in Databases, AutoML@PKDD/ECML 2017, Skopje, Macedonia, September 22, 2017

Autores
Brazdil, P; Vanschoren, J; Hutter, F; Hoos, H;

Publicação
AutoML@PKDD/ECML

Abstract

2017

Data mining techniques for the grouping of certified wines from the sub-regions of the demarcated region of Vinho Verde [Técnicas de data mining para agrupamento dos vinhos certificados das sub-regiões da região demarcada dos Vinhos Verdes]

Autores
Souza Roza, R; Brazdil, P; Reis, JL; Cerdeira, A; Martins, P; Felgueiras, O;

Publicação
Atas da Conferencia da Associacao Portuguesa de Sistemas de Informacao

Abstract
The combination of information obtained from data mining technique from physicochemical and organoleptic data analysis allowed similarities between the wines of the nine sub-regions in the Demarcated Region of Vinho Verde. Through clustering techniques, four clusters were identified, each characterized by its centroid. The measure of information gain, together with supervised rule-based learning, was used to find the differentiating characteristics. This study allowed the interconnection of the characteristics of the wines of these sub-regions, which can improve the decision making on the profiles of these same wines.

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