Search Results for author: João Tiago Ascensão

Found 9 papers, 2 papers with code

Adversarial training for tabular data with attack propagation

no code implementations28 Jul 2023 Tiago Leon Melo, João Bravo, Marco O. P. Sampaio, Paolo Romano, Hugo Ferreira, João Tiago Ascensão, Pedro Bizarro

Adversarial attacks are a major concern in security-centered applications, where malicious actors continuously try to mislead Machine Learning (ML) models into wrongly classifying fraudulent activity as legitimate, whereas system maintainers try to stop them.

Feature Engineering Fraud Detection

The GANfather: Controllable generation of malicious activity to improve defence systems

no code implementations25 Jul 2023 Ricardo Ribeiro Pereira, Jacopo Bono, João Tiago Ascensão, David Aparício, Pedro Ribeiro, Pedro Bizarro

In the former, our method moves cumulative amounts close to 350 thousand dollars through a network of accounts without being detected by an existing system.

Recommendation Systems

Lightweight Automated Feature Monitoring for Data Streams

no code implementations18 Jul 2022 João Conde, Ricardo Moreira, João Torres, Pedro Cardoso, Hugo R. C. Ferreira, Marco O. P. Sampaio, João Tiago Ascensão, Pedro Bizarro

We propose a flexible system, Feature Monitoring (FM), that detects data drifts in such data sets, with a small and constant memory footprint and a small computational cost in streaming applications.

Anti-Money Laundering Alert Optimization Using Machine Learning with Graphs

no code implementations14 Dec 2021 Ahmad Naser Eddin, Jacopo Bono, David Aparício, David Polido, João Tiago Ascensão, Pedro Bizarro, Pedro Ribeiro

Money laundering is a global problem that concerns legitimizing proceeds from serious felonies (1. 7-4 trillion euros annually) such as drug dealing, human trafficking, or corruption.

BIG-bench Machine Learning

Active learning for imbalanced data under cold start

no code implementations16 Jul 2021 Ricardo Barata, Miguel Leite, Ricardo Pacheco, Marco O. P. Sampaio, João Tiago Ascensão, Pedro Bizarro

Modern systems that rely on Machine Learning (ML) for predictive modelling, may suffer from the cold-start problem: supervised models work well but, initially, there are no labels, which are costly or slow to obtain.

Active Learning Fraud Detection

Machine learning methods to detect money laundering in the Bitcoin blockchain in the presence of label scarcity

1 code implementation29 May 2020 Joana Lorenz, Maria Inês Silva, David Aparício, João Tiago Ascensão, Pedro Bizarro

First, we show that existing state-of-the-art solutions using unsupervised anomaly detection methods are inadequate to detect the illicit patterns in a real Bitcoin transaction dataset.

Active Learning Unsupervised Anomaly Detection

ARMS: Automated rules management system for fraud detection

1 code implementation14 Feb 2020 David Aparício, Ricardo Barata, João Bravo, João Tiago Ascensão, Pedro Bizarro

We propose ARMS, an automated rules management system that evaluates the contribution of individual rules and optimizes the set of active rules using heuristic search and a user-defined loss-function.

Fraud Detection Management

Interleaved Sequence RNNs for Fraud Detection

no code implementations14 Feb 2020 Bernardo Branco, Pedro Abreu, Ana Sofia Gomes, Mariana S. C. Almeida, João Tiago Ascensão, Pedro Bizarro

Payment card fraud causes multibillion dollar losses for banks and merchants worldwide, often fueling complex criminal activities.

Feature Engineering Fraud Detection

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