arXiv subjects

Theodoros Georgiou

Publications and source records attributed to Theodoros Georgiou.

7 recordsLinked to original sources

arXiv2026

Faulty Coffees: Barriers to Adoption of an In-the-wild Robo-Barista

We set out to study whether task-based narratives could influence long-term engagement with a service robot. To do so, we deployed a Robo-Barista for five weeks in an over-50's housing complex in Stockton, England. Residents received a free daily coffee by interacting with a Furhat robot assigned to either a narrative or non-narrative dialogue condition. Despite designing for sustained engagement, repeat interaction was low, and we encountered curiosity trials without retention, technical breakdowns, accessibility barriers, and the social dynamics of a housing complex setting. Rather than treating these as peripheral issues, we foreground them in this paper. We reflect on the in-the-wild realities of our experiment and offer lessons for conducting longitudinal Human-Robot Interaction research when studies unravel in practice.

cs.RO↗

arXiv2025

Brain-Robot Interface for Exercise Mimicry

For social robots to maintain long-term engagement as exercise instructors, rapport-building is essential. Motor mimicry--imitating one's physical actions--during social interaction has long been recognized as a powerful tool for fostering rapport, and it is widely used in rehabilitation exercises where patients mirror a physiotherapist or video demonstration. We developed a novel Brain-Robot Interface (BRI) that allows a social robot instructor to mimic a patient's exercise movements in real-time, using mental commands derived from the patient's intention. The system was evaluated in an exploratory study with 14 participants (3 physiotherapists and 11 hemiparetic patients recovering from stroke or other injuries). We found our system successfully demonstrated exercise mimicry in 12 sessions; however, accuracy varied. Participants had positive perceptions of the robot instructor, with high trust and acceptance levels, which were not affected by the introduction of BRI technology.

cs.RO↗

arXiv2023

Investigating Concerns of Security and Privacy Among Rohingya Refugees in Malaysia

The security and privacy of refugee communities have emerged as pressing concerns in the context of increasing global migration. The Rohingya refugees are a stateless Muslim minority group in Myanmar who were forced to flee their homes after conflict broke out, with many fleeing to neighbouring countries and ending up in refugee camps, such as in Bangladesh. However, others migrated to Malaysia and those who arrive there live within the community as urban refugees. However, the Rohingya in Malaysia are not legally recognized and have limited and restricted access to public resources such as healthcare and education. This means they face security and privacy challenges, different to other refugee groups, which are often compounded by this lack of recognition, social isolation and lack of access to vital resources. This paper discusses the implications of security and privacy of the Rohingya refugees, focusing on available and accessible technological assistance, uncovering the heightened need for a human-centered approach to design and implementation of solutions that factor in these requirements. Overall, the discussions and findings presented in this paper on the security and privacy of the Rohingya provides a valuable resource for researchers, practitioners and policymakers in the wider HCI community.

cs.CY↗

arXiv2022

Deep Learning for Instance Retrieval: A Survey

In recent years a vast amount of visual content has been generated and shared from many fields, such as social media platforms, medical imaging, and robotics. This abundance of content creation and sharing has introduced new challenges, particularly that of searching databases for similar content-Content Based Image Retrieval (CBIR)-a long-established research area in which improved efficiency and accuracy are needed for real-time retrieval. Artificial intelligence has made progress in CBIR and has significantly facilitated the process of instance search. In this survey we review recent instance retrieval works that are developed based on deep learning algorithms and techniques, with the survey organized by deep network architecture types, deep features, feature embedding and aggregation methods, and network fine-tuning strategies. Our survey considers a wide variety of recent methods, whereby we identify milestone work, reveal connections among various methods and present the commonly used benchmarks, evaluation results, common challenges, and propose promising future directions.

cs.CV↗

arXiv2021

PREPRINT: Comparison of deep learning and hand crafted features for mining simulation data

Computational Fluid Dynamics (CFD) simulations are a very important tool for many industrial applications, such as aerodynamic optimization of engineering designs like cars shapes, airplanes parts etc. The output of such simulations, in particular the calculated flow fields, are usually very complex and hard to interpret for realistic three-dimensional real-world applications, especially if time-dependent simulations are investigated. Automated data analysis methods are warranted but a non-trivial obstacle is given by the very large dimensionality of the data. A flow field typically consists of six measurement values for each point of the computational grid in 3D space and time (velocity vector values, turbulent kinetic energy, pressure and viscosity). In this paper we address the task of extracting meaningful results in an automated manner from such high dimensional data sets. We propose deep learning methods which are capable of processing such data and which can be trained to solve relevant tasks on simulation data, i.e. predicting drag and lift forces applied on an airfoil. We also propose an adaptation of the classical hand crafted features known from computer vision to address the same problem and compare a large variety of descriptors and detectors. Finally, we compile a large dataset of 2D simulations of the flow field around airfoils which contains 16000 flow fields with which we tested and compared approaches. Our results show that the deep learning-based methods, as well as hand crafted feature based approaches, are well-capable to accurately describe the content of the CFD simulation output on the proposed dataset.

cs.CV↗

arXiv2021

Preprint: Norm Loss: An efficient yet effective regularization method for deep neural networks

Convolutional neural network training can suffer from diverse issues like exploding or vanishing gradients, scaling-based weight space symmetry and covariant-shift. In order to address these issues, researchers develop weight regularization methods and activation normalization methods. In this work we propose a weight soft-regularization method based on the Oblique manifold. The proposed method uses a loss function which pushes each weight vector to have a norm close to one, i.e. the weight matrix is smoothly steered toward the so-called Oblique manifold. We evaluate our method on the very popular CIFAR-10, CIFAR-100 and ImageNet 2012 datasets using two state-of-the-art architectures, namely the ResNet and wide-ResNet. Our method introduces negligible computational overhead and the results show that it is competitive to the state-of-the-art and in some cases superior to it. Additionally, the results are less sensitive to hyperparameter settings such as batch size and regularization factor.

cs.CV↗

arXiv2019

A Comparison of CNN and Classic Features for Image Retrieval

Feature detectors and descriptors have been successfully used for various computer vision tasks, such as video object tracking and content-based image retrieval. Many methods use image gradients in different stages of the detection-description pipeline to describe local image structures. Recently, some, or all, of these stages have been replaced by convolutional neural networks (CNNs), in order to increase their performance. A detector is defined as a selection problem, which makes it more challenging to implement as a CNN. They are therefore generally defined as regressors, converting input images to score maps and keypoints can be selected with non-maximum suppression. This paper discusses and compares several recent methods that use CNNs for keypoint detection. Experiments are performed both on the CNN based approaches, as well as a selection of conventional methods. In addition to qualitative measures defined on keypoints and descriptors, the bag-of-words (BoW) model is used to implement an image retrieval application, in order to determine how the methods perform in practice. The results show that each type of features are best in different contexts.

cs.CV↗