20 research outputs found
UJM at CLEF in Author Verification based on optimized classification trees
No full texthttp://ceur-ws.org/Vol-1180/CLEF2014wn-Pan-FreryEt2014.pdfInternational audienceThis article describes our proposal for the Author Identification task in the PAN CLEF Challenge 2014. We have adopted a machine learning ap- proach based on several representations of the texts and on optimized decision trees which have as entry various attributes and which are learned for every train- ing corpus separately for this classification task. Our method ranked us at the 2nd place with an overall AUC of 70.7%, and C@1 of 68.4% and, between the 1st and the 6th place on the six corpora
UJM at CLEF in Author Verification based on optimized classification trees
No full texthttp://ceur-ws.org/Vol-1180/CLEF2014wn-Pan-FreryEt2014.pdfInternational audienceThis article describes our proposal for the Author Identification task in the PAN CLEF Challenge 2014. We have adopted a machine learning ap- proach based on several representations of the texts and on optimized decision trees which have as entry various attributes and which are learned for every train- ing corpus separately for this classification task. Our method ranked us at the 2nd place with an overall AUC of 70.7%, and C@1 of 68.4% and, between the 1st and the 6th place on the six corpora
Apprentissage Ensembliste sur des flux de données extrêmement déséquilibrés
No full textL'apprentissage machine est l'étude de la conception d'algorithmes qui apprennent à partir des données d'apprentissage pour réaliser une tâche spécifique. Le modèle résultant est ensuite utilisé pour prédire de nouveaux points de données (invisibles) sans aucune aide extérieure. Ces données peuvent prendre de nombreuses formes telles que des images (matrice de pixels), des signaux (sons,...), des transactions (âge, montant, commerçant,...), des journaux (temps, alertes, ...). Les ensembles de données peuvent être définis pour traiter une tâche spécifique telle que la reconnaissance d'objets, l'identification vocale, la détection d'anomalies, etc. Dans ces tâches, la connaissance des résultats escomptés encourage une approche d'apprentissage supervisé où chaque donnée observée est assignée à une étiquette qui définit ce que devraient être les prédictions du modèle. Par exemple, dans la reconnaissance d'objets, une image pourrait être associée à l'étiquette "voiture" qui suggère que l'algorithme d'apprentissage doit apprendre qu'une voiture est contenue dans cette image, quelque part. Cela contraste avec l'apprentissage non supervisé où la tâche à accomplir n'a pas d'étiquettes explicites. Par exemple, un sujet populaire dans l'apprentissage non supervisé est de découvrir les structures sous-jacentes contenues dans les données visuelles (images) telles que les formes géométriques des objets, les lignes, la profondeur, avant d'apprendre une tâche spécifique. Ce type d'apprentissage est évidemment beaucoup plus difficile car il peut y avoir un nombre infini de concepts à saisir dans les données. Dans cette thèse, nous nous concentrons sur un scénario spécifique du cadre d'apprentissage supervisé : 1) l'étiquette d'intérêt est sous-représentée (p. ex. anomalies) et 2) l'ensemble de données augmente avec le temps à mesure que nous recevons des données d'événements réels (p. ex. transactions par carte de crédit). En fait, ces deux problèmes sont très fréquents dans le domaine industriel dans lequel cette thèse se déroule.Machine learning is the study of designing algorithms that learn from trainingdata to achieve a specific task. The resulting model is then used to predict overnew (unseen) data points without any outside help. This data can be of manyforms such as images (matrix of pixels), signals (sounds,...), transactions (age,amount, merchant,...), logs (time, alerts, ...). Datasets may be defined to addressa specific task such as object recognition, voice identification, anomaly detection,etc. In these tasks, the knowledge of the expected outputs encourages a supervisedlearning approach where every single observed data is assigned to a label thatdefines what the model predictions should be. For example, in object recognition,an image could be associated with the label "car" which suggests that the learningalgorithm has to learn that a car is contained in this picture, somewhere. This is incontrast with unsupervised learning where the task at hand does not have explicitlabels. For example, one popular topic in unsupervised learning is to discoverunderlying structures contained in visual data (images) such as geometric formsof objects, lines, depth, before learning a specific task. This kind of learning isobviously much harder as there might be potentially an infinite number of conceptsto grasp in the data. In this thesis, we focus on a specific scenario of thesupervised learning setting: 1) the label of interest is under represented (e.g.anomalies) and 2) the dataset increases with time as we receive data from real-lifeevents (e.g. credit card transactions). In fact, these settings are very common inthe industrial domain in which this thesis takes place
UJM at CLEF in Author Verification based on optimized classification trees. Notebook for PAN at CLEF 2014
No full textUJM at CLEF in Author Verification based on optimized classification trees. Notebook for PAN at CLEF 2014
No full text
Author Correction: A detailed characterization of complex networks using Information Theory (Scientific Reports, (2019), 9, 1, (16689), 10.1038/s41598-019-53167-5)
No full text© 2021, The Author(s). An amendment to this paper has been published and can be accessed via a link at the top of the paper
Unsupervised Change Detection Driven by Floating References: A Pattern Analysis Approach
No full text© 2021, The Author(s), under exclusive licence to Springer-Verlag London Ltd. part of Springer Nature. The Earth’s environment is continually changing due to both human and natural factors. Timely identification of the location and kind of change is of paramount importance in several areas of application. Because of that, remote sensing change detection is a topic of great interest. The development of precise change detection methods is a constant challenge. This study introduces a novel unsupervised change detection method based on data clustering and optimization. The proposal is less dependent on radiometric normalization than classical approaches. We carried experiments with remote sensing images and simulated datasets to compare the proposed method with other unsupervised well-known techniques. At its best, the proposal improves by 50% the accuracy concerning the second best technique. Such improvement is most noticeable with uncalibrated data. Experiments with simulated data reveal that the proposal is better than all other compared methods at any practical significance level. The results show the potential of the proposed method
Privacy-Preserving Tree-Based Inference with Fully Homomorphic Encryption
Get PDFPrivacy enhancing technologies (PETs) have been proposed as a way to protect the privacy of data while still allowing for data analysis. In this work, we focus on Fully Homomorphic Encryption (FHE), a powerful tool that allows for arbitrary computations to be performed on encrypted data. FHE has received lots of attention in the past few years and has reached realistic execution times and correctness.
More precisely, we explain in this paper how we apply FHE to tree-based models and get state-of-the-art solutions over encrypted tabular data. We show that our method is applicable to a wide range of tree-based models, including decision trees, random forests, and gradient boosted trees, and has been implemented within the Concrete-ML library, which is open-source at https://github.com/zama-ai/concrete-ml. With a selected set of use-cases, we demonstrate that our FHE version is very close to the unprotected version in terms of accuracy
