Search Results for author: Elvin Isufi

Found 32 papers, 5 papers with code

Learning graphs and simplicial complexes from data

no code implementations16 Dec 2023 Andrei Buciulea, Elvin Isufi, Geert Leus, Antonio G. Marques

Graphs are widely used to represent complex information and signal domains with irregular support.

On the Trade-Off between Stability and Representational Capacity in Graph Neural Networks

no code implementations4 Dec 2023 Zhan Gao, Amanda Prorok, Elvin Isufi

Analyzing the stability of graph neural networks (GNNs) under topological perturbations is key to understanding their transferability and the role of each architecture component.

Uncertainty in Graph Contrastive Learning with Bayesian Neural Networks

no code implementations30 Nov 2023 Alexander Möllers, Alexander Immer, Elvin Isufi, Vincent Fortuin

Graph contrastive learning has shown great promise when labeled data is scarce, but large unlabeled datasets are available.

Contrastive Learning Node Classification

Hodge-Compositional Edge Gaussian Processes

1 code implementation30 Oct 2023 Maosheng Yang, Viacheslav Borovitskiy, Elvin Isufi

We propose principled Gaussian processes (GPs) for modeling functions defined over the edge set of a simplicial 2-complex, a structure similar to a graph in which edges may form triangular faces.

Gaussian Processes Hyperparameter Optimization

Hodge-Aware Contrastive Learning

no code implementations14 Sep 2023 Alexander Möllers, Alexander Immer, Vincent Fortuin, Elvin Isufi

We leverage this decomposition to develop a contrastive self-supervised learning approach for processing simplicial data and generating embeddings that encapsulate specific spectral information. Specifically, we encode the pertinent data invariances through simplicial neural networks and devise augmentations that yield positive contrastive examples with suitable spectral properties for downstream tasks.

Contrastive Learning Self-Supervised Learning

Convolutional Learning on Simplicial Complexes

no code implementations26 Jan 2023 Maosheng Yang, Elvin Isufi

We propose a simplicial complex convolutional neural network (SCCNN) to learn data representations on simplicial complexes.

Trajectory Prediction

Online Filtering over Expanding Graphs

no code implementations17 Jan 2023 Bishwadeep Das, Elvin Isufi

We propose an online update of the filter, based on the principles of online machine learning.

Denoising Recommendation Systems

Deep Statistical Solver for Distribution System State Estimation

1 code implementation4 Jan 2023 Benjamin Habib, Elvin Isufi, Ward van Breda, Arjen Jongepier, Jochen L. Cremer

While data-driven alternatives based on Machine Learning models could be a choice, they suffer in DSSE because of the lack of labeled data.

Weakly-supervised Learning

Graph Filters for Signal Processing and Machine Learning on Graphs

no code implementations16 Nov 2022 Elvin Isufi, Fernando Gama, David I. Shuman, Santiago Segarra

For time series and image data that reside on Euclidean domains, filters are the crux of many signal processing and machine learning techniques, including convolutional neural networks.

Time Series Time Series Analysis

Learning Stable Graph Neural Networks via Spectral Regularization

no code implementations13 Nov 2022 Zhan Gao, Elvin Isufi

Stability of graph neural networks (GNNs) characterizes how GNNs react to graph perturbations and provides guarantees for architecture performance in noisy scenarios.

Movie Recommendation

Graph-Time Convolutional Neural Networks: Architecture and Theoretical Analysis

no code implementations30 Jun 2022 Mohammad Sabbaqi, Elvin Isufi

The proposed approach can work with any type of product graph and we also introduce a parametric product graph to learn also the spatiotemporal coupling.

Anomaly Detection

Learning Expanding Graphs for Signal Interpolation

no code implementations15 Mar 2022 Bishwadeep Das, Elvin Isufi

Specifically, we propose a stochastic attachment model for incoming nodes parameterized by the attachment probabilities and edge weights.

Collaborative Filtering

Graph filtering over expanding graphs

no code implementations15 Mar 2022 Bishwadeep Das, Elvin Isufi

We propose a filter learning scheme for data over expanding graphs by relying only on such a model.

Denoising

Learning Stochastic Graph Neural Networks with Constrained Variance

no code implementations29 Jan 2022 Zhan Gao, Elvin Isufi

To overcome this issue, we propose a variance-constrained optimization problem for SGNNs, balancing the expected performance and the stochastic deviation.

Convolutional Filtering in Simplicial Complexes

no code implementations29 Jan 2022 Elvin Isufi, Maosheng Yang

This paper proposes convolutional filtering for data whose structure can be modeled by a simplicial complex (SC).

Simplicial Convolutional Filters

no code implementations27 Jan 2022 Maosheng Yang, Elvin Isufi, Michael T. Schaub, Geert Leus

We study linear filters for processing signals supported on abstract topological spaces modeled as simplicial complexes, which may be interpreted as generalizations of graphs that account for nodes, edges, triangular faces etc.

Learning Time-Varying Graphs from Online Data

no code implementations21 Oct 2021 Alberto Natali, Elvin Isufi, Mario Coutino, Geert Leus

This work proposes an algorithmic framework to learn time-varying graphs from online data.

Graph Learning

Simplicial Convolutional Neural Networks

no code implementations6 Oct 2021 Maosheng Yang, Elvin Isufi, Geert Leus

Graphs can model networked data by representing them as nodes and their pairwise relationships as edges.

Link Prediction

Stability of Graph Convolutional Neural Networks to Stochastic Perturbations

no code implementations19 Jun 2021 Zhan Gao, Elvin Isufi, Alejandro Ribeiro

In particular, it proves the expected output difference between the GCNN over random perturbed graphs and the GCNN over the nominal graph is upper bounded by a factor that is linear in the link loss probability.

Finite Impulse Response Filters for Simplicial Complexes

no code implementations23 Mar 2021 Maosheng Yang, Elvin Isufi, Michael T. Schaub, Geert Leus

In this paper, we study linear filters to process signals defined on simplicial complexes, i. e., signals defined on nodes, edges, triangles, etc.

Denoising

Graph-Time Convolutional Neural Networks

no code implementations2 Mar 2021 Elvin Isufi, Gabriele Mazzola

We develop a graph-time convolutional filter by following the shift-and-sum principles of the convolutional operator to learn higher-level features over the product graph.

Nonlinear State-Space Generalizations of Graph Convolutional Neural Networks

no code implementations27 Oct 2020 Luana Ruiz, Fernando Gama, Alejandro Ribeiro, Elvin Isufi

In this work, we approach GCNNs from a state-space perspective revealing that the graph convolutional module is a minimalistic linear state-space model, in which the state update matrix is the graph shift operator.

Authorship Attribution

Online Time-Varying Topology Identification via Prediction-Correction Algorithms

no code implementations22 Oct 2020 Alberto Natali, Mario Coutino, Elvin Isufi, Geert Leus

Signal processing and machine learning algorithms for data supported over graphs, require the knowledge of the graph topology.

Graph-Adaptive Activation Functions for Graph Neural Networks

1 code implementation14 Sep 2020 Bianca Iancu, Luana Ruiz, Alejandro Ribeiro, Elvin Isufi

Activation functions are crucial in graph neural networks (GNNs) as they allow defining a nonlinear family of functions to capture the relationship between the input graph data and their representations.

Recommendation Systems

Stochastic Graph Neural Networks

no code implementations4 Jun 2020 Zhan Gao, Elvin Isufi, Alejandro Ribeiro

Graph neural networks (GNNs) model nonlinear representations in graph data with applications in distributed agent coordination, control, and planning among others.

Forecasting Multi-Dimensional Processes over Graphs

no code implementations17 Apr 2020 Alberto Natali, Elvin Isufi, Geert Leus

The forecasting of multi-variate time processes through graph-based techniques has recently been addressed under the graph signal processing framework.

Time Series Time Series Analysis

Graphs, Convolutions, and Neural Networks: From Graph Filters to Graph Neural Networks

1 code implementation8 Mar 2020 Fernando Gama, Elvin Isufi, Geert Leus, Alejandro Ribeiro

We also introduce GNN extensions using edge-varying and autoregressive moving average graph filters and discuss their properties.

Recommendation Systems

EdgeNets:Edge Varying Graph Neural Networks

1 code implementation21 Jan 2020 Elvin Isufi, Fernando Gama, Alejandro Ribeiro

This is a general linear and local operation that a node can perform and encompasses under one formulation all existing graph convolutional neural networks (GCNNs) as well as graph attention networks (GATs).

Graph Attention

Generalizing Graph Convolutional Neural Networks with Edge-Variant Recursions on Graphs

no code implementations4 Mar 2019 Elvin Isufi, Fernando Gama, Alejandro Ribeiro

This paper reviews graph convolutional neural networks (GCNNs) through the lens of edge-variant graph filters.

General Classification

On the Transferability of Spectral Graph Filters

no code implementations29 Jan 2019 Ron Levie, Elvin Isufi, Gitta Kutyniok

For filters in this space, the perturbation in the filter is bounded by a constant times the perturbation in the graph, and filters in the Cayley smoothness space are thus termed linearly stable.

Adaptive Graph Signal Processing: Algorithms and Optimal Sampling Strategies

no code implementations12 Sep 2017 Paolo Di Lorenzo, Paolo Banelli, Elvin Isufi, Sergio Barbarossa, Geert Leus

Numerical simulations carried out over both synthetic and real data illustrate the good performance of the proposed sampling and reconstruction strategies for (possibly distributed) adaptive learning of signals defined over graphs.

Graph Sampling

Autoregressive Moving Average Graph Filtering

no code implementations14 Feb 2016 Elvin Isufi, Andreas Loukas, Andrea Simonetto, Geert Leus

We design a family of autoregressive moving average (ARMA) recursions, which (i) are able to approximate any desired graph frequency response, and (ii) give exact solutions for tasks such as graph signal denoising and interpolation.

Denoising Philosophy

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