Search Results for author: João Gama

Found 20 papers, 6 papers with code

A Neuro-Symbolic Explainer for Rare Events: A Case Study on Predictive Maintenance

no code implementations21 Apr 2024 João Gama, Rita P. Ribeiro, Saulo Mastelini, Narjes Davarid, Bruno Veloso

The system can present global explanations for the black box model and local explanations for why the black box model predicts a failure.

Anomaly Detection

Super-Resolution Analysis for Landfill Waste Classification

no code implementations2 Apr 2024 Matias Molina, Rita P. Ribeiro, Bruno Veloso, João Gama

Illegal landfills are a critical issue due to their environmental, economic, and public health impacts.

Classification domain classification +1

Unveiling Group-Specific Distributed Concept Drift: A Fairness Imperative in Federated Learning

1 code implementation12 Feb 2024 Teresa Salazar, João Gama, Helder Araújo, Pedro Henriques Abreu

In the evolving field of machine learning, ensuring fairness has become a critical concern, prompting the development of algorithms designed to mitigate discriminatory outcomes in decision-making processes.

Decision Making Fairness +1

Turning the Tables: Biased, Imbalanced, Dynamic Tabular Datasets for ML Evaluation

2 code implementations24 Nov 2022 Sérgio Jesus, José Pombal, Duarte Alves, André Cruz, Pedro Saleiro, Rita P. Ribeiro, João Gama, Pedro Bizarro

The suite was generated by applying state-of-the-art tabular data generation techniques on an anonymized, real-world bank account opening fraud detection dataset.

Fairness Fraud Detection +1

A Benchmark dataset for predictive maintenance

no code implementations12 Jul 2022 Bruno Veloso, João Gama, Rita P. Ribeiro, Pedro M. Pereira

The paper describes the MetroPT data set, an outcome of a eXplainable Predictive Maintenance (XPM) project with an urban metro public transportation service in Porto, Portugal.

Anomaly Detection BIG-bench Machine Learning

Contextualization for the Organization of Text Documents Streams

no code implementations30 May 2022 Rui Portocarrero Sarmento, Douglas O. Cardoso, João Gama, Pavel Brazdil

The results provide a new view for the contextualization of similarity when approaching flux of documents organization tasks, based on the similarity between documents in the flux, and by using mentioned algorithms.

Information Retrieval Retrieval

Federated Anomaly Detection over Distributed Data Streams

no code implementations16 May 2022 Paula Raissa Silva, João Vinagre, João Gama

This work complements the state-of-the-art by adapting the data stream algorithms in a federated learning setting for anomaly detection and by delivering a robust framework and demonstrating the practical feasibility in a real-world distributed deployment scenario.

Anomaly Detection Federated Learning

Forecasting Financial Market Structure from Network Features using Machine Learning

no code implementations22 Oct 2021 Douglas Castilho, Tharsis T. P. Souza, Soong Moon Kang, João Gama, André C. P. L. F. de Carvalho

For such, market structure is modeled as a dynamic asset network by quantifying time-dependent co-movement of asset price returns across company constituents of major global market indices.

BIG-bench Machine Learning Management

How can I choose an explainer? An Application-grounded Evaluation of Post-hoc Explanations

no code implementations21 Jan 2021 Sérgio Jesus, Catarina Belém, Vladimir Balayan, João Bento, Pedro Saleiro, Pedro Bizarro, João Gama

We conducted an experiment following XAI Test to evaluate three popular post-hoc explanation methods -- LIME, SHAP, and TreeInterpreter -- on a real-world fraud detection task, with real data, a deployed ML model, and fraud analysts.

Decision Making Explainable Artificial Intelligence (XAI) +1

Mining Human Mobility Data to Discover Locations and Habits

no code implementations25 Sep 2019 Thiago Andrade, Brais Cancela, João Gama

Many aspects of life are associated with places of human mobility patterns and nowadays we are facing an increase in the pervasiveness of mobile devices these individuals carry.

Clustering

Contextual One-Class Classification in Data Streams

no code implementations9 Jul 2019 Richard Hugh Moulton, Herna L. Viktor, Nathalie Japkowicz, João Gama

We conclude that the paradigm of contexts in data streams can be used to improve the performance of streaming one-class classifiers.

Classification General Classification +2

A scalable saliency-based Feature selection method with instance level information

1 code implementation30 Apr 2019 Brais Cancela, Verónica Bolón-Canedo, Amparo Alonso-Betanzos, João Gama

Classic feature selection techniques remove those features that are either irrelevant or redundant, achieving a subset of relevant features that help to provide a better knowledge extraction.

feature selection

Identifying Points of Interest and Similar Individuals from Raw GPS Data

no code implementations19 Apr 2019 Thiago Andrade, João Gama

Smartphones and portable devices have become ubiquitous and part of everyone's life.

EigenEvent: An Algorithm for Event Detection from Complex Data Streams in Syndromic Surveillance

1 code implementation13 Jun 2014 Hadi Fanaee-T, João Gama

Experimental results on hundred sets of benchmark data reveals that EigenEvent presents a better overall performance comparing state-of-the-art, in particular in terms of the false alarm rate.

Event Detection

Eigenspace Method for Spatiotemporal Hotspot Detection

no code implementations13 Jun 2014 Hadi Fanaee-T, João Gama

STScan makes some restrictive assumptions about the distribution of data, the shape of the hotspots and the quality of data, which can be unrealistic for some nontraditional data sources.

Computational Efficiency

Event and Anomaly Detection Using Tucker3 Decomposition

no code implementations12 Jun 2014 Hadi Fanaee-T, Márcia D. B. Oliveira, João Gama, Simon Malinowski, Ricardo Morla

Among unsupervised approaches, Principal Component Analysis (PCA) is a well-known solution which has been widely used in the anomaly detection literature and can be applied to matrix data (e. g. Users-Features).

Anomaly Detection

Posterior vs Parameter Sparsity in Latent Variable Models

no code implementations NeurIPS 2009 Kuzman Ganchev, Ben Taskar, Fernando Pereira, João Gama

We apply this new method to learn first-order HMMs for unsupervised part-of-speech (POS) tagging, and show that HMMs learned this way consistently and significantly out-performs both EM-trained HMMs, and HMMs with a sparsity-inducing Dirichlet prior trained by variational EM.

Part-Of-Speech Tagging POS +1

Learning with local drift detection

1 code implementation Advanced Data Mining and Applications, Second International Conference, ADMA 2006 João Gama, Gladys Castillo

In this work we present experiments using the method as a wrapper over a decision tree and a linear model, and in each internal-node of a decision tree.

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