Search Results for author: Nikolaos Gkalelis

Found 8 papers, 5 papers with code

T-TAME: Trainable Attention Mechanism for Explaining Convolutional Networks and Vision Transformers

no code implementations7 Mar 2024 Mariano V. Ntrougkas, Nikolaos Gkalelis, Vasileios Mezaris

While some techniques for generating explanations have been proposed, primarily for Convolutional Neural Networks, adapting such techniques to the new paradigm of Vision Transformers is non-trivial.

Explanation Generation

Filter-Pruning of Lightweight Face Detectors Using a Geometric Median Criterion

1 code implementation28 Nov 2023 Konstantinos Gkrispanis, Nikolaos Gkalelis, Vasileios Mezaris

Face detectors are becoming a crucial component of many applications, including surveillance, that often have to run on edge devices with limited processing power and memory.

Face Detection Network Pruning

Gated-ViGAT: Efficient Bottom-Up Event Recognition and Explanation Using a New Frame Selection Policy and Gating Mechanism

1 code implementation18 Jan 2023 Nikolaos Gkalelis, Dimitrios Daskalakis, Vasileios Mezaris

In this paper, Gated-ViGAT, an efficient approach for video event recognition, utilizing bottom-up (object) information, a new frame sampling policy and a gating mechanism is proposed.

Graph Attention

TAME: Attention Mechanism Based Feature Fusion for Generating Explanation Maps of Convolutional Neural Networks

1 code implementation18 Jan 2023 Mariano Ntrougkas, Nikolaos Gkalelis, Vasileios Mezaris

TAME can easily be applied to any convolutional neural network (CNN) by streamlining the optimization of the attention mechanism's training method and the selection of target model's feature maps.

Learning Visual Explanations for DCNN-Based Image Classifiers Using an Attention Mechanism

1 code implementation22 Sep 2022 Ioanna Gkartzonika, Nikolaos Gkalelis, Vasileios Mezaris

In this paper two new learning-based eXplainable AI (XAI) methods for deep convolutional neural network (DCNN) image classifiers, called L-CAM-Fm and L-CAM-Img, are proposed.

Explainable Artificial Intelligence (XAI)

ViGAT: Bottom-up event recognition and explanation in video using factorized graph attention network

1 code implementation20 Jul 2022 Nikolaos Gkalelis, Dimitrios Daskalakis, Vasileios Mezaris

In this paper a pure-attention bottom-up approach, called ViGAT, that utilizes an object detector together with a Vision Transformer (ViT) backbone network to derive object and frame features, and a head network to process these features for the task of event recognition and explanation in video, is proposed.

Graph Attention

Accelerated kernel discriminant analysis

no code implementations27 Apr 2015 Nikolaos Gkalelis, Vasileios Mezaris

In this paper, using a novel matrix factorization and simultaneous reduction to diagonal form approach (or in short simultaneous reduction approach), Accelerated Kernel Discriminant Analysis (AKDA) and Accelerated Kernel Subclass Discriminant Analysis (AKSDA) are proposed.

General Classification

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