Search Results for author: Luiz S. Oliveira

Found 24 papers, 8 papers with code

Fast & Furious: Modelling Malware Detection as Evolving Data Streams

1 code implementation24 May 2022 Fabrício Ceschin, Marcus Botacin, Heitor Murilo Gomes, Felipe Pinagé, Luiz S. Oliveira, André Grégio

This constant evolution of malware samples causes changes to the data distribution (i. e., concept drifts) that directly affect ML model detection rates, something not considered in the majority of the literature work.

Malware Detection

Classifier Pool Generation based on a Two-level Diversity Approach

no code implementations3 Nov 2020 Marcos Monteiro, Alceu S. Britto Jr, Jean P. Barddal, Luiz S. Oliveira, Robert Sabourin

This paper describes a classifier pool generation method guided by the diversity estimated on the data complexity and classifier decisions.

Vocal Bursts Valence Prediction

Machine Learning (In) Security: A Stream of Problems

no code implementations30 Oct 2020 Fabrício Ceschin, Marcus Botacin, Albert Bifet, Bernhard Pfahringer, Luiz S. Oliveira, Heitor Murilo Gomes, André Grégio

Machine Learning (ML) has been widely applied to cybersecurity and is considered state-of-the-art for solving many of the open issues in that field.

BIG-bench Machine Learning

A Comprehensive Comparison of End-to-End Approaches for Handwritten Digit String Recognition

no code implementations29 Oct 2020 Andre G. Hochuli, Alceu S. Britto Jr, David A. Saji, Jose M. Saavedra, Robert Sabourin, Luiz S. Oliveira

Over the last decades, most approaches proposed for handwritten digit string recognition (HDSR) have resorted to digit segmentation, which is dominated by heuristics, thereby imposing substantial constraints on the final performance.

object-detection Object Detection +1

Intrapersonal Parameter Optimization for Offline Handwritten Signature Augmentation

no code implementations13 Oct 2020 Teruo M. Maruyama, Luiz S. Oliveira, Alceu S. Britto Jr, Robert Sabourin

The method is used to generate offline signatures in the image and the feature space and train an ASVS.

Single-sample writers -- "Document Filter" and their impacts on writer identification

no code implementations18 May 2020 Fabio Pinhelli, Alceu S. Britto Jr, Luiz S. Oliveira, Yandre M. G. Costa, Diego Bertolini

The writing can be used as an important biometric modality which allows to unequivocally identify an individual.

Ocular Recognition Databases and Competitions: A Survey

no code implementations21 Nov 2019 Luiz A. Zanlorensi, Rayson Laroca, Eduardo Luz, Alceu S. Britto Jr., Luiz S. Oliveira, David Menotti

The use of the iris and periocular region as biometric traits has been extensively investigated, mainly due to the singularity of the iris features and the use of the periocular region when the image resolution is not sufficient to extract iris information.

Meta-learning for fast classifier adaptation to new users of Signature Verification systems

1 code implementation17 Oct 2019 Luiz G. Hafemann, Robert Sabourin, Luiz S. Oliveira

This is particularly challenging for skilled forgeries, where a forger practices imitating the user's signature, and often is able to create forgeries visually close to the original signatures.

Meta-Learning

Evaluating Competence Measures for Dynamic Regressor Selection

no code implementations9 Apr 2019 Thiago J. M. Moura, George D. C. Cavalcanti, Luiz S. Oliveira

Three DRS systems were compared against individual regressor and static systems that use the Mean and the Median to combine the outputs of the regressors from the ensemble.

regression

Characterizing and evaluating adversarial examples for Offline Handwritten Signature Verification

2 code implementations10 Jan 2019 Luiz G. Hafemann, Robert Sabourin, Luiz S. Oliveira

The phenomenon of Adversarial Examples is attracting increasing interest from the Machine Learning community, due to its significant impact to the security of Machine Learning systems.

BIG-bench Machine Learning Object Recognition

Decoupling Direction and Norm for Efficient Gradient-Based L2 Adversarial Attacks and Defenses

5 code implementations23 Nov 2018 Jérôme Rony, Luiz G. Hafemann, Luiz S. Oliveira, Ismail Ben Ayed, Robert Sabourin, Eric Granger

Research on adversarial examples in computer vision tasks has shown that small, often imperceptible changes to an image can induce misclassification, which has security implications for a wide range of image processing systems.

Fixed-sized representation learning from Offline Handwritten Signatures of different sizes

1 code implementation2 Apr 2018 Luiz G. Hafemann, Robert Sabourin, Luiz S. Oliveira

Methods for learning feature representations for Offline Handwritten Signature Verification have been successfully proposed in recent literature, using Deep Convolutional Neural Networks to learn representations from signature pixels.

Representation Learning

A Robust Real-Time Automatic License Plate Recognition Based on the YOLO Detector

2 code implementations26 Feb 2018 Rayson Laroca, Evair Severo, Luiz A. Zanlorensi, Luiz S. Oliveira, Gabriel Resende Gonçalves, William Robson Schwartz, David Menotti

First, in the SSIG dataset, composed of 2, 000 frames from 101 vehicle videos, our system achieved a recognition rate of 93. 53% and 47 Frames Per Second (FPS), performing better than both Sighthound and OpenALPR commercial systems (89. 80% and 93. 03%, respectively) and considerably outperforming previous results (81. 80%).

Data Augmentation License Plate Detection +2

Learning Features for Offline Handwritten Signature Verification using Deep Convolutional Neural Networks

4 code implementations16 May 2017 Luiz G. Hafemann, Robert Sabourin, Luiz S. Oliveira

Verifying the identity of a person using handwritten signatures is challenging in the presence of skilled forgeries, where a forger has access to a person's signature and deliberately attempt to imitate it.

Analyzing features learned for Offline Signature Verification using Deep CNNs

no code implementations15 Jul 2016 Luiz G. Hafemann, Robert Sabourin, Luiz S. Oliveira

Research on Offline Handwritten Signature Verification explored a large variety of handcrafted feature extractors, ranging from graphology, texture descriptors to interest points.

Writer-independent Feature Learning for Offline Signature Verification using Deep Convolutional Neural Networks

no code implementations4 Apr 2016 Luiz G. Hafemann, Robert Sabourin, Luiz S. Oliveira

Automatic Offline Handwritten Signature Verification has been researched over the last few decades from several perspectives, using insights from graphology, computer vision, signal processing, among others.

Offline Handwritten Signature Verification - Literature Review

no code implementations28 Jul 2015 Luiz G. Hafemann, Robert Sabourin, Luiz S. Oliveira

The area of Handwritten Signature Verification has been broadly researched in the last decades, but remains an open research problem.

PKLot-A robust dataset for parking lot classification

no code implementations Expert Systems with Applications 2015 Paulo R.L. de Almeida, Luiz S. Oliveira, Alceu S. Britto Jr., Eunelson J. Silva Jr., Alessandro L. Koerich

To mitigate this difficulty, in this paper we introduce a new parking lot dataset composed of 695, 899 images captured from two parking lots with three different camera views.

Benchmarking Classification +1

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