Search Results for author: Argyris Kalogeratos

Found 22 papers, 2 papers with code

Collaborative non-parametric two-sample testing

no code implementations8 Feb 2024 Alejandro de la Concha, Nicolas Vayatis, Argyris Kalogeratos

This paper addresses the multiple two-sample test problem in a graph-structured setting, which is a common scenario in fields such as Spatial Statistics and Neuroscience.

Two-sample testing

Stein Boltzmann Sampling: A Variational Approach for Global Optimization

no code implementations7 Feb 2024 Gaëtan Serré, Argyris Kalogeratos, Nicolas Vayatis

In this paper, we introduce a new flow-based method for global optimization of Lipschitz functions, called Stein Boltzmann Sampling (SBS).

UniForCE: The Unimodality Forest Method for Clustering and Estimation of the Number of Clusters

1 code implementation18 Dec 2023 Georgios Vardakas, Argyris Kalogeratos, Aristidis Likas

In this work, we focus on the concept of unimodality and propose a flexible cluster definition called locally unimodal cluster.

Clustering

Online non-parametric likelihood-ratio estimation by Pearson-divergence functional minimization

no code implementations3 Nov 2023 Alejandro de la Concha, Nicolas Vayatis, Argyris Kalogeratos

Quantifying the difference between two probability density functions, $p$ and $q$, using available data, is a fundamental problem in Statistics and Machine Learning.

A framework for paired-sample hypothesis testing for high-dimensional data

no code implementations28 Sep 2023 Ioannis Bargiotas, Argyris Kalogeratos, Nicolas Vayatis

First, we estimate the bisecting hyperplanes for each pair of instances and an aggregated rule derived through the Hodges-Lehmann estimator.

Two-sample testing

To tree or not to tree? Assessing the impact of smoothing the decision boundaries

no code implementations7 Oct 2022 Anthea Mérida, Argyris Kalogeratos, Mathilde Mougeot

The approach we propose starts with the rigid decision boundaries of a seed Decision Tree (seed DT), which is used to initialize a Neural DT (NDT).

Model Selection

Clustering for directed graphs using parametrized random walk diffusion kernels

no code implementations1 Oct 2022 Harry Sevi, Matthieu Jonckheere, Argyris Kalogeratos

In this paper, we introduce a new clustering framework, the Parametrized Random Walk Diffusion Kernel Clustering (P-RWDKC), which is suitable for handling both directed and undirected graphs.

Clustering

Collaborative likelihood-ratio estimation over graphs

no code implementations28 May 2022 Alejandro de la Concha, Nicolas Vayatis, Argyris Kalogeratos

In this paper, we introduce the first -to the best of our knowledge-graph-based extension of this problem, which reads as follows: Suppose each node $v$ of a fixed graph has access to observations coming from two unknown node-specific pdfs, $p_v$ and $q_v$, and the goal is to estimate for each node the likelihood-ratio between both pdfs by also taking into account the information provided by the graph structure.

Generalized Spectral Clustering for Directed and Undirected Graphs

no code implementations7 Mar 2022 Harry Sevi, Matthieu Jonckheere, Argyris Kalogeratos

In this paper, we present a generalized spectral clustering framework that can address both directed and undirected graphs.

Clustering graph partitioning

Winning the competition: enhancing counter-contagion in SIS-like epidemic processes

no code implementations24 Jun 2020 Argyris Kalogeratos, Stefano Sarao Mannelli

In this paper we consider the epidemic competition between two generic diffusion processes, where each competing side is represented by a different state of a stochastic process.

Model family selection for classification using Neural Decision Trees

no code implementations20 Jun 2020 Anthea Mérida Montes de Oca, Argyris Kalogeratos, Mathilde Mougeot

In our approach, this is realized by progressively relaxing the decision boundaries of the initial decision trees (the RMs) as long as this is beneficial in terms of performance measured on an analyzed dataset.

Classification General Classification +1

Offline detection of change-points in the mean for stationary graph signals

1 code implementation18 Jun 2020 Alejandro de la Concha, Nicolas Vayatis, Argyris Kalogeratos

This paper addresses the problem of segmenting a stream of graph signals: we aim to detect changes in the mean of a multivariate signal defined over the nodes of a known graph.

Change Point Detection Model Selection +1

Optimal Multiple Stopping Rule for Warm-Starting Sequential Selection

no code implementations12 Feb 2020 Mathilde Fekom, Nicolas Vayatis, Argyris Kalogeratos

In this paper we present the Warm-starting Dynamic Thresholding algorithm, developed using dynamic programming, for a variant of the standard online selection problem.

Learning the piece-wise constant graph structure of a varying Ising model

no code implementations ICML 2020 Batiste Le Bars, Pierre Humbert, Argyris Kalogeratos, Nicolas Vayatis

This work focuses on the estimation of multiple change-points in a time-varying Ising model that evolves piece-wise constantly.

Sequential Dynamic Resource Allocation for Epidemic Control

no code implementations20 Sep 2019 Mathilde Fekom, Nicolas Vayatis, Argyris Kalogeratos

Under the Dynamic Resource Allocation (DRA) model, an administrator has the mission to allocate dynamically a limited budget of resources to the nodes of a network in order to reduce a diffusion process (DP) (e. g. an epidemic).

Revealing posturographic features associated with the risk of falling in patients with Parkinsonian syndromes via machine learning

no code implementations15 Jul 2019 Ioannis Bargiotas, Argyris Kalogeratos, Myrto Limnios, Pierre-Paul Vidal, Damien Ricard, Nicolas Vayatis

In this work, we present the ts-AUC, a non-parametric multivariate two-sample test, which we employ to analyze statokinesigram differences among PS patients that are fallers (PSf) and non-fallers (PSNF).

A Probabilistic Framework to Node-level Anomaly Detection in Communication Networks

no code implementations12 Feb 2019 Batiste Le Bars, Argyris Kalogeratos

In this paper we consider the task of detecting abnormal communication volume occurring at node-level in communication networks.

Anomaly Detection

A Spectral Method for Activity Shaping in Continuous-Time Information Cascades

no code implementations15 Sep 2017 Kevin Scaman, Argyris Kalogeratos, Luca Corinzia, Nicolas Vayatis

Information Cascades Model captures dynamical properties of user activity in a social network.

Multivariate Hawkes Processes for Large-scale Inference

no code implementations26 Feb 2016 Rémi Lemonnier, Kevin Scaman, Argyris Kalogeratos

In this paper, we present a framework for fitting multivariate Hawkes processes for large-scale problems both in the number of events in the observed history $n$ and the number of event types $d$ (i. e. dimensions).

Dip-means: an incremental clustering method for estimating the number of clusters

no code implementations NeurIPS 2012 Argyris Kalogeratos, Aristidis Likas

The proposed algorithm considers each cluster member as a ''viewer'' and applies a univariate statistic hypothesis test for unimodality (dip-test) on the distribution of the distances between the viewer and the cluster members.

Clustering

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