Search Results for author: Vassilis N. Ioannidis

Found 32 papers, 12 papers with code

STaRK: Benchmarking LLM Retrieval on Textual and Relational Knowledge Bases

1 code implementation19 Apr 2024 Shirley Wu, Shiyu Zhao, Michihiro Yasunaga, Kexin Huang, Kaidi Cao, Qian Huang, Vassilis N. Ioannidis, Karthik Subbian, James Zou, Jure Leskovec

Answering real-world user queries, such as product search, often requires accurate retrieval of information from semi-structured knowledge bases or databases that involve blend of unstructured (e. g., textual descriptions of products) and structured (e. g., entity relations of products) information.

NetInfoF Framework: Measuring and Exploiting Network Usable Information

1 code implementation12 Feb 2024 Meng-Chieh Lee, Haiyang Yu, Jian Zhang, Vassilis N. Ioannidis, Xiang Song, Soji Adeshina, Da Zheng, Christos Faloutsos

Given a node-attributed graph, and a graph task (link prediction or node classification), can we tell if a graph neural network (GNN) will perform well?

Link Prediction Node Classification

BioBridge: Bridging Biomedical Foundation Models via Knowledge Graphs

1 code implementation5 Oct 2023 Zifeng Wang, Zichen Wang, Balasubramaniam Srinivasan, Vassilis N. Ioannidis, Huzefa Rangwala, Rishita Anubhai

Foundation models (FMs) are able to leverage large volumes of unlabeled data to demonstrate superior performance across a wide range of tasks.

Cross-Modal Retrieval Domain Generalization +3

TouchUp-G: Improving Feature Representation through Graph-Centric Finetuning

no code implementations25 Sep 2023 Jing Zhu, Xiang Song, Vassilis N. Ioannidis, Danai Koutra, Christos Faloutsos

How can we enhance the node features acquired from Pretrained Models (PMs) to better suit downstream graph learning tasks?

Domain Adaptation Graph Learning +2

Pitfalls in Link Prediction with Graph Neural Networks: Understanding the Impact of Target-link Inclusion & Better Practices

no code implementations1 Jun 2023 Jing Zhu, YuHang Zhou, Vassilis N. Ioannidis, Shengyi Qian, Wei Ai, Xiang Song, Danai Koutra

While Graph Neural Networks (GNNs) are remarkably successful in a variety of high-impact applications, we demonstrate that, in link prediction, the common practices of including the edges being predicted in the graph at training and/or test have outsized impact on the performance of low-degree nodes.

Link Prediction Node Classification

Train Your Own GNN Teacher: Graph-Aware Distillation on Textual Graphs

1 code implementation20 Apr 2023 Costas Mavromatis, Vassilis N. Ioannidis, Shen Wang, Da Zheng, Soji Adeshina, Jun Ma, Han Zhao, Christos Faloutsos, George Karypis

Different from conventional knowledge distillation, GRAD jointly optimizes a GNN teacher and a graph-free student over the graph's nodes via a shared LM.

Knowledge Distillation Node Classification

OrthoReg: Improving Graph-regularized MLPs via Orthogonality Regularization

no code implementations31 Jan 2023 Hengrui Zhang, Shen Wang, Vassilis N. Ioannidis, Soji Adeshina, Jiani Zhang, Xiao Qin, Christos Faloutsos, Da Zheng, George Karypis, Philip S. Yu

Graph Neural Networks (GNNs) are currently dominating in modeling graph-structure data, while their high reliance on graph structure for inference significantly impedes them from widespread applications.

Node Classification

Variational Causal Inference

2 code implementations13 Sep 2022 Yulun Wu, Layne C. Price, Zichen Wang, Vassilis N. Ioannidis, Robert A. Barton, George Karypis

Estimating an individual's potential outcomes under counterfactual treatments is a challenging task for traditional causal inference and supervised learning approaches when the outcome is high-dimensional (e. g. gene expressions, impulse responses, human faces) and covariates are relatively limited.

Causal Inference counterfactual

Efficient and effective training of language and graph neural network models

no code implementations22 Jun 2022 Vassilis N. Ioannidis, Xiang Song, Da Zheng, Houyu Zhang, Jun Ma, Yi Xu, Belinda Zeng, Trishul Chilimbi, George Karypis

The effectiveness in our framework is achieved by applying stage-wise fine-tuning of the BERT model first with heterogenous graph information and then with a GNN model.

Edge Classification Language Modelling +1

A Robust Stacking Framework for Training Deep Graph Models with Multifaceted Node Features

no code implementations16 Jun 2022 Jiuhai Chen, Jonas Mueller, Vassilis N. Ioannidis, Tom Goldstein, David Wipf

Graph Neural Networks (GNNs) with numerical node features and graph structure as inputs have demonstrated superior performance on various supervised learning tasks with graph data.

TempoQR: Temporal Question Reasoning over Knowledge Graphs

1 code implementation10 Dec 2021 Costas Mavromatis, Prasanna Lakkur Subramanyam, Vassilis N. Ioannidis, Soji Adeshina, Phillip R. Howard, Tetiana Grinberg, Nagib Hakim, George Karypis

The first computes a textual representation of a given question, the second combines it with the entity embeddings for entities involved in the question, and the third generates question-specific time embeddings.

Entity Embeddings Graph Question Answering +4

Does your graph need a confidence boost? Convergent boosted smoothing on graphs with tabular node features

1 code implementation26 Oct 2021 Jiuhai Chen, Jonas Mueller, Vassilis N. Ioannidis, Soji Adeshina, Yangkun Wang, Tom Goldstein, David Wipf

For supervised learning with tabular data, decision tree ensembles produced via boosting techniques generally dominate real-world applications involving iid training/test sets.

Scalable Consistency Training for Graph Neural Networks via Self-Ensemble Self-Distillation

no code implementations12 Oct 2021 Cole Hawkins, Vassilis N. Ioannidis, Soji Adeshina, George Karypis

Consistency training is a popular method to improve deep learning models in computer vision and natural language processing.

Convergent Boosted Smoothing for Modeling GraphData with Tabular Node Features

no code implementations ICLR 2022 Jiuhai Chen, Jonas Mueller, Vassilis N. Ioannidis, Soji Adeshina, Yangkun Wang, Tom Goldstein, David Wipf

Many practical modeling tasks require making predictions using tabular data composed of heterogeneous feature types (e. g., text-based, categorical, continuous, etc.).

Unveiling Anomalous Edges and Nominal Connectivity of Attributed Networks

no code implementations17 Apr 2021 Konstantinos D. Polyzos, Costas Mavromatis, Vassilis N. Ioannidis, Georgios B. Giannakis

Uncovering anomalies in attributed networks has recently gained popularity due to its importance in unveiling outliers and flagging adversarial behavior in a gamut of data and network science applications including {the Internet of Things (IoT)}, finance, security, to list a few.

PanRep: Universal node embeddings for heterogeneous graphs

no code implementations28 Sep 2020 Vassilis N. Ioannidis, Da Zheng, George Karypis

Learning unsupervised node embeddings facilitates several downstream tasks such as node classification and link prediction.

Link Prediction Node Classification

PanRep: Graph neural networks for extracting universal node embeddings in heterogeneous graphs

1 code implementation20 Jul 2020 Vassilis N. Ioannidis, Da Zheng, George Karypis

Learning unsupervised node embeddings facilitates several downstream tasks such as node classification and link prediction.

Link Prediction Node Classification

Few-shot link prediction via graph neural networks for Covid-19 drug-repurposing

1 code implementation20 Jul 2020 Vassilis N. Ioannidis, Da Zheng, George Karypis

This paper proposes an inductive RGCN for learning informative relation embeddings even in the few-shot learning regime.

Drug Discovery Few-Shot Learning +5

Pruned Graph Scattering Transforms

no code implementations ICLR 2020 Vassilis N. Ioannidis, Siheng Chen, Georgios B. Giannakis

Graph convolutional networks (GCNs) have achieved remarkable performance in a variety of network science learning tasks.

Tensor Graph Convolutional Networks for Multi-relational and Robust Learning

no code implementations15 Mar 2020 Vassilis N. Ioannidis, Antonio G. Marques, Georgios B. Giannakis

The era of "data deluge" has sparked renewed interest in graph-based learning methods and their widespread applications ranging from sociology and biology to transportation and communications.

Sociology

Efficient and Stable Graph Scattering Transforms via Pruning

no code implementations27 Jan 2020 Vassilis N. Ioannidis, Siheng Chen, Georgios B. Giannakis

The resultant pruning algorithm is guided by a graph-spectrum-inspired criterion, and retains informative scattering features on-the-fly while bypassing the exponential complexity associated with GSTs.

3D Point Cloud Classification Graph Learning +1

Edge Dithering for Robust Adaptive Graph Convolutional Networks

no code implementations21 Oct 2019 Vassilis N. Ioannidis, Georgios B. Giannakis

Graph convolutional networks (GCNs) are vulnerable to perturbations of the graph structure that are either random, or, adversarially designed.

GraphSAC: Detecting anomalies in large-scale graphs

no code implementations21 Oct 2019 Vassilis N. Ioannidis, Dimitris Berberidis, Georgios B. Giannakis

Alleviating this limitation, GraphSAC randomly draws subsets of nodes, and relies on graph-aware criteria to judiciously filter out sets contaminated by anomalous nodes, before employing a semi-supervised learning (SSL) module to estimate nominal label distributions per node.

Anomaly Detection

A Recurrent Graph Neural Network for Multi-Relational Data

1 code implementation5 Nov 2018 Vassilis N. Ioannidis, Antonio G. Marques, Georgios B. Giannakis

The era of data deluge has sparked the interest in graph-based learning methods in a number of disciplines such as sociology, biology, neuroscience, or engineering.

Sociology

Semi-Blind Inference of Topologies and Dynamical Processes over Graphs

no code implementations16 May 2018 Vassilis N. Ioannidis, Yanning Shen, Georgios B. Giannakis

Alleviating the limited flexibility of existing approaches, this work advocates structural models for graph processes and develops novel algorithms for joint inference of the network topology and processes from partial nodal observations.

Sociology

Kernel-based Inference of Functions over Graphs

no code implementations28 Nov 2017 Vassilis N. Ioannidis, Meng Ma, Athanasios N. Nikolakopoulos, Georgios B. Giannakis, Daniel Romero

The study of networks has witnessed an explosive growth over the past decades with several ground-breaking methods introduced.

Inference of Spatio-Temporal Functions over Graphs via Multi-Kernel Kriged Kalman Filtering

no code implementations25 Nov 2017 Vassilis N. Ioannidis, Daniel Romero, Georgios B. Giannakis

Inference of space-time varying signals on graphs emerges naturally in a plethora of network science related applications.

Kernel-based Reconstruction of Space-time Functions on Dynamic Graphs

no code implementations12 Dec 2016 Daniel Romero, Vassilis N. Ioannidis, Georgios B. Giannakis

Graph-based methods pervade the inference toolkits of numerous disciplines including sociology, biology, neuroscience, physics, chemistry, and engineering.

Sociology

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