Search Results for author: Aristides Gionis

Found 23 papers, 14 papers with code

Diversity-aware clustering: Computational Complexity and Approximation Algorithms

no code implementations10 Jan 2024 Suhas Thejaswi, Ameet Gadekar, Bruno Ordozgoiti, Aristides Gionis

We present parameterized approximation algorithms with approximation ratios $1+ \frac{2}{e}$, $1+\frac{8}{e}$ and $3$ for diversity-aware $k$-median, diversity-aware $k$-means and diversity-aware $k$-supplier, respectively.

Clustering

Rebalancing Social Feed to Minimize Polarization and Disagreement

1 code implementation28 Aug 2023 Federico Cinus, Aristides Gionis, Francesco Bonchi

Social media have great potential for enabling public discourse on important societal issues.

Adversaries with Limited Information in the Friedkin--Johnsen Model

1 code implementation17 Jun 2023 Sijing Tu, Stefan Neumann, Aristides Gionis

To address this concern, we raise the following question: Can an attacker sow discord in a social network, even when only the network topology is known?

Open-Ended Question Answering Sociology

Learning Cellular Coverage from Real Network Configurations using GNNs

1 code implementation20 Apr 2023 Yifei Jin, Marios Daoutis, Sarunas Girdzijauskas, Aristides Gionis

Cellular coverage quality estimation has been a critical task for self-organized networks.

Concise and interpretable multi-label rule sets

1 code implementation4 Oct 2022 Martino Ciaperoni, Han Xiao, Aristides Gionis

Multi-label classification is becoming increasingly ubiquitous, but not much attention has been paid to interpretability.

Multi-Label Classification

Regularized impurity reduction: Accurate decision trees with complexity guarantees

1 code implementation23 Aug 2022 Guangyi Zhang, Aristides Gionis

In this paper, we justify the use of a general family of impurity functions, including the popular functions of entropy and Gini-index, in scenarios where small trees are desirable, by showing that a simple enhancement can equip them with complexity guarantees.

Open World Learning Graph Convolution for Latency Estimation in Routing Networks

no code implementations8 Jul 2022 Yifei Jin, Marios Daoutis, Sarunas Girdzijauskas, Aristides Gionis

Accurate routing network status estimation is a key component in Software Defined Networking.

Generalized Leverage Scores: Geometric Interpretation and Applications

no code implementations16 Jun 2022 Bruno Ordozgoiti, Antonis Matakos, Aristides Gionis

In particular, leverage scores, which relate the columns of a matrix to the subspaces spanned by its leading singular vectors, are helpful in revealing column subsets to approximately factorize a matrix with quality guarantees.

Ranking with submodular functions on a budget

1 code implementation8 Apr 2022 Guangyi Zhang, Nikolaj Tatti, Aristides Gionis

In more detail, given a set of items and a set of non-decreasing submodular functions, where each function is associated with a budget, we aim to find a ranking of the set of items that maximizes the sum of values achieved by all functions under the budget constraints.

Marketing

Improved analysis of randomized SVD for top-eigenvector approximation

no code implementations16 Feb 2022 Ruo-Chun Tzeng, Po-An Wang, Florian Adriaens, Aristides Gionis, Chi-Jen Lu

We present a novel analysis of the randomized SVD algorithm of \citet{halko2011finding} and derive tight bounds in many cases of interest.

Discovering conflicting groups in signed networks

1 code implementation NeurIPS 2020 Ruo-Chun Tzeng, Bruno Ordozgoiti, Aristides Gionis

In this paper we study the problem of detecting $k$ conflicting groups in a signed network.

Clustering

Co-exposure Maximization in Online Social Networks

no code implementations NeurIPS 2020 Sijing Tu, Cigdem Aslay, Aristides Gionis

Social media has created new ways for citizens to stay informed on societal matters and participate in political discourse.

Diverse Rule Sets

1 code implementation17 Jun 2020 Guangyi Zhang, Aristides Gionis

Thus, interpretability of models has been recognized as an equally important quality as their predictive power.

Searching for polarization in signed graphs: a local spectral approach

1 code implementation26 Jan 2020 Han Xiao, Bruno Ordozgoiti, Aristides Gionis

In this paper we formulate the problem of finding local polarized communities in signed graphs as a locally-biased eigen-problem.

Finding path motifs in large temporal graphs using algebraic fingerprints

1 code implementation20 Jan 2020 Suhas Thejaswi, Aristides Gionis, Juho Lauri

In particular, given a vertex-colored temporal graph and a multiset of colors as a query, we search for temporal paths in the graph that contain the colors specified in the query.

What is the dimension of your binary data?

no code implementations4 Feb 2019 Nikolaj Tatti, Taneli Mielikainen, Aristides Gionis, Heikki Mannila

Defining the effective dimensionality of such a dataset is a nontrivial problem.

Clustering

Explainable time series tweaking via irreversible and reversible temporal transformations

1 code implementation13 Sep 2018 Isak Karlsson, Jonathan Rebane, Panagiotis Papapetrou, Aristides Gionis

We show that the problem is NP-hard, and focus on two instantiations of the problem, which we refer to as reversible and irreversible time series tweaking.

General Classification Time Series +2

Political Discourse on Social Media: Echo Chambers, Gatekeepers, and the Price of Bipartisanship

1 code implementation5 Jan 2018 Kiran Garimella, Gianmarco De Francisci Morales, Aristides Gionis, Michael Mathioudakis

By comparing the two, we find that Twitter users are, to a large degree, exposed to political opinions that agree with their own.

Social and Information Networks

Balancing information exposure in social networks

no code implementations NeurIPS 2017 Kiran Garimella, Aristides Gionis, Nikos Parotsidis, Nikolaj Tatti

Our goal is to find two sets of nodes to employ in the respective campaigns, so that the overall information exposure for the two campaigns is balanced.

Joint Non-negative Matrix Factorization for Learning Ideological Leaning on Twitter

no code implementations28 Nov 2017 Preethi Lahoti, Kiran Garimella, Aristides Gionis

We model the problem of learning the liberal-conservative ideology space of social media users and media sources as a constrained non-negative matrix-factorization problem.

Social and Information Networks

Semi-supervised Kernel Metric Learning Using Relative Comparisons

no code implementations1 Dec 2016 Ehsan Amid, Aristides Gionis, Antti Ukkonen

We consider the problem of metric learning subject to a set of constraints on relative-distance comparisons between the data items.

Clustering Metric Learning

Quantifying Controversy in Social Media

1 code implementation18 Jul 2015 Kiran Garimella, Gianmarco De Francisci Morales, Aristides Gionis, Michael Mathioudakis

Unlike previous work, rather than study controversy in a single hand-picked topic and use domain specific knowledge, we take a general approach to study topics in any domain.

Social and Information Networks

DopeLearning: A Computational Approach to Rap Lyrics Generation

1 code implementation18 May 2015 Eric Malmi, Pyry Takala, Hannu Toivonen, Tapani Raiko, Aristides Gionis

First, we develop a prediction model to identify the next line of existing lyrics from a set of candidate next lines.

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