Search Results for author: Pedro Bizarro

Found 31 papers, 7 papers with code

Cost-Sensitive Learning to Defer to Multiple Experts with Workload Constraints

no code implementations11 Mar 2024 Jean V. Alves, Diogo Leitão, Sérgio Jesus, Marco O. P. Sampaio, Javier Liébana, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

Learning to defer (L2D) aims to improve human-AI collaboration systems by learning how to defer decisions to humans when they are more likely to be correct than an ML classifier.

Fraud Detection

FiFAR: A Fraud Detection Dataset for Learning to Defer

1 code implementation20 Dec 2023 Jean V. Alves, Diogo Leitão, Sérgio Jesus, Marco O. P. Sampaio, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

Financial fraud detection is a high-stakes setting where algorithms and human experts often work in tandem; however, there are no publicly available datasets for L2D concerning this important application of human-AI teaming.

Benchmarking Decision Making +1

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

From random-walks to graph-sprints: a low-latency node embedding framework on continuous-time dynamic graphs

no code implementations17 Jul 2023 Ahmad Naser Eddin, Jacopo Bono, David Aparício, Hugo Ferreira, João Ascensão, Pedro Ribeiro, Pedro Bizarro

We demonstrate that our graph-sprints features, combined with a machine learning classifier, achieve competitive performance (outperforming all baselines for the node classification tasks in five datasets).

Graph Representation Learning Node Classification

Fairness-Aware Data Valuation for Supervised Learning

no code implementations29 Mar 2023 José Pombal, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

Data valuation is a ML field that studies the value of training instances towards a given predictive task.

Active Learning Data Valuation +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

LaundroGraph: Self-Supervised Graph Representation Learning for Anti-Money Laundering

no code implementations25 Oct 2022 Mário Cardoso, Pedro Saleiro, Pedro Bizarro

Reviewing these cases is a cumbersome and complex task that requires analysts to navigate a large network of financial interactions to validate suspicious movements.

Graph Representation Learning Link Prediction +1

FairGBM: Gradient Boosting with Fairness Constraints

1 code implementation16 Sep 2022 André F Cruz, Catarina Belém, Sérgio Jesus, João Bravo, Pedro Saleiro, Pedro Bizarro

Tabular data is prevalent in many high-stakes domains, such as financial services or public policy.

Decision Making Fairness

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.

Understanding Unfairness in Fraud Detection through Model and Data Bias Interactions

no code implementations13 Jul 2022 José Pombal, André F. Cruz, João Bravo, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

The unparalleled ability of machine learning algorithms to learn patterns from data also enables them to incorporate biases embedded within.

Decision Making Fairness +1

Prisoners of Their Own Devices: How Models Induce Data Bias in Performative Prediction

no code implementations27 Jun 2022 José Pombal, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

The unparalleled ability of machine learning algorithms to learn patterns from data also enables them to incorporate biases embedded within.

Fairness Fraud Detection

Human-AI Collaboration in Decision-Making: Beyond Learning to Defer

no code implementations27 Jun 2022 Diogo Leitão, Pedro Saleiro, Mário A. T. Figueiredo, Pedro Bizarro

Human-AI collaboration (HAIC) in decision-making aims to create synergistic teaming between human decision-makers and AI systems.

Decision Making Fairness +1

On the Importance of Application-Grounded Experimental Design for Evaluating Explainable ML Methods

no code implementations24 Jun 2022 Kasun Amarasinghe, Kit T. Rodolfa, Sérgio Jesus, Valerie Chen, Vladimir Balayan, Pedro Saleiro, Pedro Bizarro, Ameet Talwalkar, Rayid Ghani

Most existing evaluations of explainable machine learning (ML) methods rely on simplifying assumptions or proxies that do not reflect real-world use cases; the handful of more robust evaluations on real-world settings have shortcomings in their design, resulting in limited conclusions of methods' real-world utility.

Experimental Design Fraud Detection

Data+Shift: Supporting visual investigation of data distribution shifts by data scientists

no code implementations29 Apr 2022 João Palmeiro, Beatriz Malveiro, Rita Costa, David Polido, Ricardo Moreira, Pedro Bizarro

We propose Data+Shift, a visual analytics tool to support data scientists in the task of investigating the underlying factors of shift in data features in the context of fraud detection.

BIG-bench Machine Learning Fraud Detection

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

Weakly Supervised Multi-task Learning for Concept-based Explainability

no code implementations26 Apr 2021 Catarina Belém, Vladimir Balayan, Pedro Saleiro, Pedro Bizarro

In ML-aided decision-making tasks, such as fraud detection or medical diagnosis, the human-in-the-loop, usually a domain-expert without technical ML knowledge, prefers high-level concept-based explanations instead of low-level explanations based on model features.

Decision Making Fraud Detection +2

Promoting Fairness through Hyperparameter Optimization

2 code implementations23 Mar 2021 André F. Cruz, Pedro Saleiro, Catarina Belém, Carlos Soares, Pedro Bizarro

Considerable research effort has been guided towards algorithmic fairness but real-world adoption of bias reduction techniques is still scarce.

Fairness Fraud Detection +1

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

TimeSHAP: Explaining Recurrent Models through Sequence Perturbations

1 code implementation30 Nov 2020 João Bento, Pedro Saleiro, André F. Cruz, Mário A. T. Figueiredo, Pedro Bizarro

Although recurrent neural networks (RNNs) are state-of-the-art in numerous sequential decision-making tasks, there has been little research on explaining their predictions.

Decision Making Feature Importance +3

Teaching the Machine to Explain Itself using Domain Knowledge

no code implementations27 Nov 2020 Vladimir Balayan, Pedro Saleiro, Catarina Belém, Ludwig Krippahl, Pedro Bizarro

Moreover, we collect the domain feedback from a pool of certified experts and use it to ameliorate the model (human teaching), hence promoting seamless and better suited explanations.

Decision Making Fraud Detection

A Bandit-Based Algorithm for Fairness-Aware Hyperparameter Optimization

no code implementations7 Oct 2020 André F. Cruz, Pedro Saleiro, Catarina Belém, Carlos Soares, Pedro Bizarro

Hence, coupled with the lack of tools for ML practitioners, real-world adoption of bias reduction methods is still scarce.

Decision Making Fairness +2

BreachRadar: Automatic Detection of Points-of-Compromise

no code implementations24 Sep 2020 Miguel Araujo, Miguel Almeida, Jaime Ferreira, Luis Silva, Pedro Bizarro

Bank transaction fraud results in over $13B annual losses for banks, merchants, and card holders worldwide.

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

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

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

Automatic Model Monitoring for Data Streams

no code implementations12 Aug 2019 Fábio Pinto, Marco O. P. Sampaio, Pedro Bizarro

We evaluated SAMM using human feedback from domain experts, by sending them 100 reports generated by the system.

Fraud Detection

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