Search Results for author: Aleksandar Bojchevski

Found 23 papers, 12 papers with code

Hierarchical Randomized Smoothing

no code implementations NeurIPS 2023 Yan Scholten, Jan Schuchardt, Aleksandar Bojchevski, Stephan Günnemann

Randomized smoothing is a powerful framework for making models provably robust against small changes to their inputs - by guaranteeing robustness of the majority vote when randomly adding noise before classification.

Node Classification

Probing Graph Representations

1 code implementation7 Mar 2023 Mohammad Sadegh Akhondzadeh, Vijay Lingam, Aleksandar Bojchevski

Our findings on molecular datasets show the potential of probing for understanding the inductive biases of graph-based models.

Collective Robustness Certificates: Exploiting Interdependence in Graph Neural Networks

no code implementations6 Feb 2023 Jan Schuchardt, Aleksandar Bojchevski, Johannes Gasteiger, Stephan Günnemann

In tasks like node classification, image segmentation, and named-entity recognition we have a classifier that simultaneously outputs multiple predictions (a vector of labels) based on a single input, i. e. a single graph, image, or document respectively.

Adversarial Robustness Image Segmentation +5

Are Defenses for Graph Neural Networks Robust?

no code implementations31 Jan 2023 Felix Mujkanovic, Simon Geisler, Stephan Günnemann, Aleksandar Bojchevski

A cursory reading of the literature suggests that we have made a lot of progress in designing effective adversarial defenses for Graph Neural Networks (GNNs).

Randomized Message-Interception Smoothing: Gray-box Certificates for Graph Neural Networks

1 code implementation5 Jan 2023 Yan Scholten, Jan Schuchardt, Simon Geisler, Aleksandar Bojchevski, Stephan Günnemann

To remedy this, we propose novel gray-box certificates that exploit the message-passing principle of GNNs: We randomly intercept messages and carefully analyze the probability that messages from adversarially controlled nodes reach their target nodes.

Adversarial Robustness

Localized Randomized Smoothing for Collective Robustness Certification

no code implementations28 Oct 2022 Jan Schuchardt, Tom Wollschläger, Aleksandar Bojchevski, Stephan Günnemann

We further show that this approach is beneficial for the larger class of softly local models, where each output is dependent on the entire input but assigns different levels of importance to different input regions (e. g. based on their proximity in the image).

Image Segmentation Node Classification +1

Unveiling the Sampling Density in Non-Uniform Geometric Graphs

no code implementations15 Oct 2022 Raffaele Paolino, Aleksandar Bojchevski, Stephan Günnemann, Gitta Kutyniok, Ron Levie

A powerful framework for studying graphs is to consider them as geometric graphs: nodes are randomly sampled from an underlying metric space, and any pair of nodes is connected if their distance is less than a specified neighborhood radius.

Robustness of Graph Neural Networks at Scale

2 code implementations NeurIPS 2021 Simon Geisler, Tobias Schmidt, Hakan Şirin, Daniel Zügner, Aleksandar Bojchevski, Stephan Günnemann

Graph Neural Networks (GNNs) are increasingly important given their popularity and the diversity of applications.

Provably Robust Transfer

no code implementations29 Sep 2021 Anna-Kathrin Kopetzki, Jana Obernosterer, Aleksandar Bojchevski, Stephan Günnemann

Our experiments show how adversarial training on the source domain affects robustness on source and target domain, and we propose the first provably robust transfer learning models.

Adversarial Robustness Transfer Learning

Collective Robustness Certificates

no code implementations ICLR 2021 Jan Schuchardt, Aleksandar Bojchevski, Johannes Klicpera, Stephan Günnemann

In tasks like node classification, image segmentation, and named-entity recognition we have a classifier that simultaneously outputs multiple predictions (a vector of labels) based on a single input, i. e. a single graph, image, or document respectively.

Adversarial Robustness Image Segmentation +5

Efficient Robustness Certificates for Discrete Data: Sparsity-Aware Randomized Smoothing for Graphs, Images and More

1 code implementation ICML 2020 Aleksandar Bojchevski, Johannes Gasteiger, Stephan Günnemann

Existing techniques for certifying the robustness of models for discrete data either work only for a small class of models or are general at the expense of efficiency or tightness.

Certifiable Robustness to Graph Perturbations

1 code implementation NeurIPS 2019 Aleksandar Bojchevski, Stephan Günnemann

Despite the exploding interest in graph neural networks there has been little effort to verify and improve their robustness.

Adversarial Attacks on Node Embeddings

no code implementations ICLR 2019 Aleksandar Bojchevski, Stephan Günnemann

The goal of network representation learning is to learn low-dimensional node embeddings that capture the graph structure and are useful for solving downstream tasks.

Representation Learning

Pitfalls of Graph Neural Network Evaluation

2 code implementations14 Nov 2018 Oleksandr Shchur, Maximilian Mumme, Aleksandar Bojchevski, Stephan Günnemann

We perform a thorough empirical evaluation of four prominent GNN models and show that considering different splits of the data leads to dramatically different rankings of models.

Graph Mining Node Classification

Adversarial Attacks on Node Embeddings via Graph Poisoning

1 code implementation ICLR 2019 Aleksandar Bojchevski, Stephan Günnemann

The goal of network representation learning is to learn low-dimensional node embeddings that capture the graph structure and are useful for solving downstream tasks.

Representation Learning

Dual-Primal Graph Convolutional Networks

no code implementations3 Jun 2018 Federico Monti, Oleksandr Shchur, Aleksandar Bojchevski, Or Litany, Stephan Günnemann, Michael M. Bronstein

In recent years, there has been a surge of interest in developing deep learning methods for non-Euclidean structured data such as graphs.

Graph Attention Recommendation Systems

NetGAN: Generating Graphs via Random Walks

2 code implementations ICML 2018 Aleksandar Bojchevski, Oleksandr Shchur, Daniel Zügner, Stephan Günnemann

NetGAN is able to produce graphs that exhibit well-known network patterns without explicitly specifying them in the model definition.

Graph Generation Link Prediction

Deep Gaussian Embedding of Graphs: Unsupervised Inductive Learning via Ranking

1 code implementation ICLR 2018 Aleksandar Bojchevski, Stephan Günnemann

We propose Graph2Gauss - an approach that can efficiently learn versatile node embeddings on large scale (attributed) graphs that show strong performance on tasks such as link prediction and node classification.

Link Prediction Network Embedding +1

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