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Nikos Deligiannis

23 accepted papers

2026

Temporal Concept Dynamics in Diffusion Models via Prompt-Conditioned Interventions

ICLR 2026poster

Diffusion models are usually evaluated by their final outputs, gradually denoising random noise into meaningful images. Yet, generation unfolds along a trajectory, and understanding this dynamic process is crucial for explaining how controllable, reliable, and predictable these models are in terms…

Cited by 0SourcecodeScholar
2024

Co-Occurrence Graph-Enhanced Hierarchical Prediction of ICD Codes

ICASSP 2024accepted

Recent healthcare applications of natural language processing involve multi-label classification of health records using the International Classification of Diseases (ICD). While prior research highlights intricate text models and explores external knowledge like hierarchical ICD ontology, fewer stu…

Cited by 0SourceScholar
2024

Interpreting and Analysing CLIP's Zero-Shot Image Classification via Mutual Knowledge

NeurIPS 2024poster

Contrastive Language-Image Pretraining (CLIP) performs zero-shot image classification by mapping images and textual class representation into a shared embedding space, then retrieving the class closest to the image. This work provides a new approach for interpreting CLIP models for image classificat…

2024

Learned Layered Coding for Successive Refinement in the Wyner-Ziv Problem

ICASSP 2024accepted

We propose a data-driven approach to explicitly learn the progressive encoding of a continuous source, which is successively decoded with increasing levels of quality and with the aid of correlated side information. This setup refers to the successive refinement of the Wyner-Ziv coding problem. Assu…

Cited by 0SourceScholar
2024

Unveiling Privacy Risks in Stochastic Neural Networks Training: Effective Image Reconstruction from Gradients

ECCV 2024poster

"Federated Learning (FL) provides a framework for collaborative training of deep learning models while preserving data privacy by avoiding sharing the training data. However, recent studies have shown that a malicious server can reconstruct training data from the shared gradients of traditional neur…

2023

Designing Transformer Networks for Sparse Recovery of Sequential Data Using Deep Unfolding

ICASSP 2023accepted

Deep unfolding models are designed by unrolling an optimization algorithm into a deep learning network. These models have shown faster convergence and higher performance compared to the original optimization algorithms. Additionally, by incorporating domain knowledge from the optimization algorithm,…

Cited by 0SourceScholar
2022

Gradient Variance Loss for Structure-Enhanced Image Super-Resolution

ICASSP 2022accepted

Recent success in the field of single image super-resolution (SISR) is achieved by optimizing deep convolutional neural networks (CNNs) in the image space with the L1 or L2 loss. However, when trained with these loss functions, models usually fail to recover sharp edges present in the high-resolutio…

Cited by 0SourceScholar
2022

NLX-GPT: A Model for Natural Language Explanations in Vision and Vision-Language Tasks

CVPR 2022oral

Natural language explanation (NLE) models aim at explaining the decision-making process of a black box system via generating natural language sentences which are human-friendly, high-level and fine-grained. Current NLE models explain the decision-making process of a vision or vision-language model (…

Cited by 78PDFcodeScholar
2021

Generalization error bounds for deep unfolding RNNs

UAI 2021poster

Recurrent Neural Networks (RNNs) are powerful models with the ability to model sequential data. However, they are often viewed as black-boxes and lack in interpretability. Deep unfolding methods take a step towards interpretability by designing deep neural networks as learned variations of iterative…

Cited by 18SourcePDFScholar
2021

HCGM-Net: A Deep Unfolding Network for Financial Index Tracking

ICASSP 2021accepted

Tracking the performance of a financial index by selecting a subset of assets composing the index is a problem that raises several difficulties due to the large size of the stock market. Typically, optimisation algorithms with high complexity are employed to address such problems. In this paper, we…

Cited by 0SourceScholar
2019

Matrix Completion with Variational Graph Autoencoders: Application in Hyperlocal Air Quality Inference

ICASSP 2019accepted

Inferring air quality from a limited number of observations is an essential task for monitoring and controlling air pollution. Existing inference methods typically use low spatial resolution data collected by fixed monitoring stations and infer the concentration of air pollutants using additional ty…

Cited by 0SourceScholar
2018

Twitter User Geolocation Using Deep Multiview Learning

ICASSP 2018accepted

Predicting the geographical location of users on social networks like Twitter is an active research topic with plenty of methods proposed so far. Most of the existing work follows either a content-based or a network-based approach. The former is based on user-generated content while the latter explo…

Cited by 37SourceScholar
2017

Rate-distortion trade-offs in acquisition of signal parameters

ICASSP 2017accepted

We consider problems where one wishes to represent a parameter associated with a signal source - subject to a certain rate and distortion - based on the observation of a number of realizations of the source signal. By reducing these indirect vector quantization problems to a standard vector quantiza…

Cited by 0SourceScholar
2016

Reference-based compressed sensing: A sample complexity approach

ICASSP 2016accepted

We address the problem of reference-based compressed sensing: reconstruct a sparse signal from few linear measurements using as prior information a reference signal, a signal similar to the signal we want to reconstruct. Access to reference signals arises in applications such as medical imaging, e.g…

Cited by 0SourceScholar
2015

Dynamic sparse state estimation using ℓ1-ℓ1 minimization: Adaptive-rate measurement bounds, algorithms and applications

ICASSP 2015accepted

We propose a recursive algorithm for estimating time-varying signals from a few linear measurements. The signals are assumed sparse, with unknown support, and are described by a dynamical model. In each iteration, the algorithm solves an ℓ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xl…

Cited by 0SourceScholar