Pages
 1
 2
 document

Isufi, E. (author), Gama, Fernando (author), Ribeiro, Alejandro (author)Driven by the outstanding performance of neural networks in the structured euclidean domain, recent years have seen a surge of interest in developing neural networks for graphs and data supported on graphs. The graph is leveraged at each layer of the neural network as a parameterization to capture detail at the node level with a reduced...journal article 2022
 document

Coutino, Mario (author), Leus, G.J.T. (author)One of the main challenges of graph filters is the stability of their design. While classical graph filters allow for a stable design using optimal polynomial approximation theory, generalized graph filters tend to suffer from the illconditioning of the involved system matrix. This issue, accentuated for increasing graph filter orders,...journal article 2022
 document

Liu, J. (author)The ability to model irregular data and the interactions between them have<br/>extended the traditional signal processing tools to the graph domain. Under<br/>these circumstances, the emergence of graph signal processing has offered a<br/>brand new framework for dealing with complex data. In particular, the graph<br/>Fourier transform (GFT) lets...doctoral thesis 2021
 document

Coutino, Mario (author)To the surprise of most of us, complexity in nature spawns from simplicity. No matter how simple a basic unit is, when many of them work together, the interactions among these units lead to complexity. This complexity is present in the spreading of diseases, where slightly different policies, or conditions,might lead to very different results;...doctoral thesis 2021
 document

Morency, M.W. (author), Leus, G.J.T. (author)Graph signal processing is an emerging field which aims to model processes that exist on the nodes of a network and are explained through diffusion over this structure. Graph signal processing works have heretofore assumed knowledge of the graph shift operator. Our approach is to investigate the question of graph filtering on a graph about...journal article 2021
 document

Isufi, E. (author), Pocchiari, Matteo (author), Hanjalic, A. (author)Graph convolutions, in both their linear and neural network forms, have reached stateoftheart accuracy on recommender system (RecSys) benchmarks. However, recommendation accuracy is tied with diversity in a delicate tradeoff and the potential of graph convolutions to improve the latter is unexplored. Here, we develop a model that learns...journal article 2021
 document

Leus, G.J.T. (author), Yang, Maosheng (author), Coutino, Mario (author), Isufi, E. (author)To deal with highdimensional data, graph filters have shown their power in both graph signal processing and data science. However, graph filters process signals exploiting only pairwise interactions between the nodes, and they are not able to exploit more complicated topological structures. Graph Volterra models, on the other hand, are also...conference paper 2021
 document

Pocchiari, M. (author)Recommender Systems assist the user by suggesting items to be consumed based on the user's history. The topic of diversity in recommendation gained momentum in recent years as additional criterion besides recommendation accuracy, to improve user satisfaction. Accuracy and diversity in recommender systems coexist in a delicate tradeoff due to...master thesis 2020
 document

Li, Qiongxiu (author), Coutino, Mario (author), Leus, G.J.T. (author), Christensen, M. Graesboll (author)With an increasingly interconnected and digitized world, distributed signal processing and graph signal processing have been proposed to process its big amount of data. However, privacy has become one of the biggest challenges holding back the widespread adoption of these tools for processing sensitive data. As a step towards a solution, we...conference paper 2020
 document

Rimleanscaia, Oxana (author), Isufi, E. (author)This paper proposes rational Chebyshev graph filters to approximate step graph spectral responses with arbitrary precision, which are of interest in graph filter banks and spectral clustering. The proposed method relies on the wellknown Chebyshev filters of the first kind and on a domain transform of the angular frequencies to the graph...conference paper 2020
 document

Natali, A. (author), Coutino, Mario (author), Leus, G.J.T. (author)Data defined over a network have been successfully modelled by means of graph filters. However, although in many scenarios the connectivity of the network is known, e.g., smart grids, social networks, etc., the lack of welldefined interaction weights hinders the ability to model the observed networked data using graph filters. Therefore, in...conference paper 2020
 document

Isufi, E. (author)The necessity to process signals living in nonEuclidean domains, such as signals defined on the top of a graph, has led to the extension of signal processing techniques to the graph setting. Among different approaches, graph signal processing distinguishes itself by providing a Fourier analysis of these signals. Analogously to the Fourier...doctoral thesis 2019
 document

Gama, F. (author), Marques, Antonio G. (author), Leus, G.J.T. (author), Ribeiro, Alejandro (author)Two architectures that generalize convolutional neural networks (CNNs) for the processing of signals supported on graphs are introduced. We start with the selection graph neural network (GNN), which replaces linear time invariant filters with linear shift invariant graph filters to generate convolutional features and reinterprets pooling as a...journal article 2019
 document

AittomÃ¤ki, Tuomas (author), Leus, G.J.T. (author)Graph filters are an essential part of signal processing on graphs enabling one to modify the spectral content of the graph signals. This paper proposes a graph filter optimization method with an exact control of the ripple on the passband and the stopband of the filter. The proposed filter design method is based on the sumofsquares...conference paper 2019
 document

Coutino, Mario (author), Isufi, E. (author), Leus, G.J.T. (author)Graph filters are one of the core tools in graph signal processing. A central aspect of them is their direct distributed implementation. However, the filtering performance is often traded with distributed communication and computational savings. To improve this tradeoff, this paper generalizes stateoftheart distributed graph filters to...journal article 2019
 document

Coutino, Mario (author), Isufi, E. (author), Maehara, Takanori (author), Leus, G.J.T. (author)In this work, we explore the limits of finitetime distributed consensus through the intersection of graph filters and matrix function theory. We focus on algorithms capable to compute the consensus exactly through filtering operations over a graph, and that have been proven to converge in finite time. In this context, we show that there...conference paper 2019
 document

Coutino, Mario (author), Leus, G.J.T. (author)As the size of the sensor network grows, synchronization starts to become the main bottleneck for distributed computing. As a result, efforts in several areas have been focused on the convergence analysis of asynchronous computational methods. In this work, we aim to crosspollinate distributed graph filters with results in parallel computing...conference paper 2019
 document

Liu, J. (author), Isufi, E. (author), Leus, G.J.T. (author)In the field of signal processing on graphs, graph filters play a crucial role in processing the spectrum of graph signals. This paper proposes two different strategies for designing autoregressive moving average (ARMA) graph filters on both directed and undirected graphs. The first approach is inspired by Prony&#x0027;s method, which...journal article 2018
 document

Coutino, Mario (author), Isufi, E. (author), Leus, G.J.T. (author)The main challenges distributed graph filters face in practice are the communication overhead and computational complexity. In this work, we extend the stateoftheart distributed finite impulse response (FIR) graph filters to an edgevariant (EV) version, i.e., a filter where every node weights the signals from its neighbors with different...conference paper 2018
 document

Isufi, E. (author), Di Lorenzo, Paolo (author), Banelli, Paolo (author), Leus, G.J.T. (author)This paper proposes strategies for distributed Wienerbased reconstruction of graph signals from subsampled measurements. Given a stationary signal on a graph, we fit a distributed autoregressive moving average graph filter to a Wiener graph frequency response and propose two reconstruction strategies: i) reconstruction from a single temporal...conference paper 2018
Pages
 1
 2