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Yannis Panagakis

34 accepted papers

2026

Exposing Hidden Biases in Text-to-Image Models via Automated Prompt Search

ICML 2026poster

Text-to-image (TTI) diffusion models have achieved remarkable visual quality, yet they have been repeatedly shown to exhibit social biases across sensitive attributes such as gender, race and age. To mitigate these biases, existing approaches frequently depend on curated prompt datasets - either man…

Cited by 0SourceScholar
2026

Language Models are Injective and Hence Invertible

ICLR 2026poster

Transformer components such as non-linear activations and normalization are inherently non-injective, suggesting that different inputs could map to the same output and prevent exact recovery of the input from a model’s representations. In this paper, we challenge this view. First, we prove mathemati…

Cited by 0SourcecodeScholar
2026

Neural Collapse by Design: Learning Class Prototypes on the Hypersphere

ICML 2026poster

Supervised classifier learning has a theoretical optimum — Neural Collapse (NC) — yet standard training does not reach it in practice. We trace this failure to a geometric limitation: cross-entropy is invariant to joint rescaling of features and weights, leaving radial degrees of freedom unconstrain…

Cited by 0SourceScholar
2026

PolySAE: Modeling Feature Interactions in Sparse Autoencoders via Polynomial Decoding

ICML 2026poster

Sparse autoencoders (SAEs) have emerged as a promising method for interpreting neural network representations by decomposing activations into sparse combinations of dictionary atoms. However, SAEs assume that features combine additively through linear reconstruction, an assumption that cannot captur…

Cited by 0SourceScholar
2025

Are Large Brainwave Foundation Models Capable Yet ? Insights from Fine-Tuning

ICML 2025poster

Foundation Models have demonstrated significant success across various domains in Artificial Intelligence (AI), yet their capabilities for brainwave modeling remain unclear. In this paper, we comprehensively evaluate current Large Brainwave Foundation Models (LBMs) through systematic fine-tuning exp…

Cited by 0SourcePDFScholar
2024

Benchmarking Counterfactual Image Generation

NeurIPS 2024poster

Generative AI has revolutionised visual content editing, empowering users to effortlessly modify images and videos. However, not all edits are equal. To perform realistic edits in domains such as natural image or medical imaging, modifications must respect causal relationships inherent to the data g…

2024

Bridging Mini-Batch and Asymptotic Analysis in Contrastive Learning: From InfoNCE to Kernel-Based Losses

ICML 2024poster

What do different contrastive learning (CL) losses actually optimize for? Although multiple CL methods have demonstrated remarkable representation learning capabilities, the differences in their inner workings remain largely opaque. In this work, we analyse several CL families and prove that, under…

2024

Investigating Personalization Methods in Text to Music Generation

ICASSP 2024accepted

In this work, we investigate the personalization of text-to-music diffusion models in a few-shot setting. Motivated by recent advances in the computer vision domain, we are the first to explore the combination of pre-trained text-to-audio diffusers with two established personalization methods. We ex…

Cited by 0SourceScholar
2024

Multilinear Mixture of Experts: Scalable Expert Specialization through Factorization

NeurIPS 2024poster

The Mixture of Experts (MoE) paradigm provides a powerful way to decompose dense layers into smaller, modular computations often more amenable to human interpretation, debugging, and editability. However, a major challenge lies in the computational cost of scaling the number of experts high enough t…

2023

MMATR: A Lightweight Approach for Multimodal Sentiment Analysis Based on Tensor Methods

ICASSP 2023accepted

Despite the considerable research output on Multimodal Learning for Affect-related tasks, most of the current methods are very complex in terms of the number of trainable parameters, and thus do not constitute effective solutions for real-life applications. In this work we try to alleviate this gap…

Cited by 0SourceScholar
2023

PandA: Unsupervised Learning of Parts and Appearances in the Feature Maps of GANs

ICLR 2023poster

Recent advances in the understanding of Generative Adversarial Networks (GANs) have led to remarkable progress in visual editing and synthesis tasks, capitalizing on the rich semantics that are embedded in the latent spaces of pre-trained GANs. However, existing methods are often tailored to specifi…

2023

Parts of Speech–Grounded Subspaces in Vision-Language Models

NeurIPS 2023poster

Latent image representations arising from vision-language models have proved immensely useful for a variety of downstream tasks. However, their utility is limited by their entanglement with respect to different visual attributes. For instance, recent work has shown that CLIP image representations ar…

2022

Augmenting Deep Classifiers with Polynomial Neural Networks

ECCV 2022poster

"Deep neural networks have been the driving force behind the success in classification tasks, e.g., object and audio recognition. Impressive results and generalization have been achieved by a variety of recently proposed architectures, the majority of which are seemingly disconnected. In this work,…

2022

Cluster-Guided Image Synthesis With Unconditional Models

CVPR 2022poster

Generative Adversarial Networks (GANs) are the driving force behind the state-of-the-art in image generation. Despite their ability to synthesize high-resolution photo-realistic images, generating content with on-demand conditioning of different granularity remains a challenge. This challenge is usu…

Cited by 4PDFScholar
2022

Efficient Learning of Multiple NLP Tasks via Collective Weight Factorization on BERT

NAACL 2022findings

The Transformer architecture continues to show remarkable performance gains in many Natural Language Processing tasks. However, obtaining such state-of-the-art performance in different tasks requires fine-tuning the same model separately for each task. Clearly, such an approach is demanding in terms…

Cited by 3SourcePDFScholar
2021

Conditional Generation Using Polynomial Expansions

NeurIPS 2021poster

Generative modeling has evolved to a notable field of machine learning. Deep polynomial neural networks (PNNs) have demonstrated impressive results in unsupervised image generation, where the task is to map an input vector (i.e., noise) to a synthesized image. However, the success of PNNs has not be…

2020

Factorized Higher-Order CNNs With an Application to Spatio-Temporal Emotion Estimation

CVPR 2020poster

Training deep neural networks with spatio-temporal (i.e., 3D) or multidimensional convolutions of higher-order is computationally challenging due to millions of unknown parameters across dozens of layers. To alleviate this, one approach is to apply low-rank tensor decompositions to convolution kerne…

Cited by 109PDFScholar
2020

Learning Differentiable Sparse and Low Rank Networks for Audio-Visual Object Localization

ICASSP 2020accepted

Parsimonious modelling, including sparsity and low rankness, has becomes a cornerstone in modern machine learning and signal processing. However, these modelling techniques have limited capabity to learn from large-scale data, and often require some pre-defined parameters to define their optimizatio…

Cited by 0SourceScholar
2020

Multilinear Latent Conditioning for Generating Unseen Attribute Combinations

ICML 2020poster

Deep generative models rely on their inductive bias to facilitate generalization, especially for problems with high dimensional data, like images. However, empirical studies have shown that variational autoencoders (VAE) and generative adversarial networks (GAN) lack the generalization ability that…

Cited by 17SourcePDFScholar
2020

P-nets: Deep Polynomial Neural Networks

CVPR 2020poster

Deep Convolutional Neural Networks (DCNNs) is currently the method of choice both for generative, as well as for discriminative learning in computer vision and machine learning. The success of DCNNs can be attributed to the careful selection of their building blocks (e.g., residual blocks, rectifier…

Cited by 95PDFcodeScholar
2020

Speech-Driven Facial Animation Using Polynomial Fusion of Features

ICASSP 2020accepted

Speech-driven facial animation involves using a speech signal to generate realistic videos of talking faces. Recent deep learning approaches to facial synthesis rely on extracting low-dimensional representations and concatenating them, followed by a decoding step of the concatenated vector. This acc…

Cited by 0SourceScholar
2017

3D Face Morphable Models "In-The-Wild"

CVPR 2017spotlight

3D Morphable Models (3DMMs) are powerful statistical models of 3D facial shape and texture, and among the state-of-the-art methods for reconstructing facial shape from single images. With the advent of new 3D sensors, many 3D facial datasets have been collected containing both neutral as well as exp…

Cited by 213PDFScholar
2017

Audio-visual object localization and separation using low-rank and sparsity

ICASSP 2017accepted

The ability to localize visual objects that are associated with an audio source and at the same time seperate the audio signal is a corner stone in several audio-visual signal processing applications. Past efforts usually focused on localizing only the visual objects, without audio separation abilit…

Cited by 0SourceScholar
2017

Robust Kronecker-Decomposable Component Analysis for Low-Rank Modeling

ICCV 2017poster

Dictionary learning and component analysis are part of one of the most well-studied and active research fields, at the intersection of signal and image processing, computer vision, and statistical machine learning. In dictionary learning, the current methods of choice are arguably K-SVD and its vari…

Cited by 14PDFcodeScholar
2017

Side Information in Robust Principal Component Analysis: Algorithms and Applications

ICCV 2017poster

Robust Principal Component Analysis (RPCA) aims at recovering a low-rank subspace from grossly corrupted high-dimensional (often visual) data and is a cornerstone in many machine learning and computer vision applications. Even though RPCA has been shown to be very successful in solving many rank min…

Cited by 12PDFScholar
2015

Automatic Construction Of Robust Spherical Harmonic Subspaces

CVPR 2015poster

In this paper we propose a method to automatically recover a class specific low dimensional spherical harmonic basis from a set of in-the-wild facial images. We combine existing techniques for uncalibrated photometric stereo and low rank matrix decompositions in order to robustly recover a combined…

Cited by 23SourcePDFScholar