Spiros Nikolopoulos

Dr. Spiros Nikolopoulos

Multimedia Knowledge and Social Media Analytics Laboratory;
+1
orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 April 2017 in ACM Computing Surveys
Verified
Journal Article
Open access
AIAnastasia Ioannidou
Anastasia Ioannidou
ECElisavet Chatzilari
Elisavet Chatzilari
Spiros NikolopoulosSpiros Nikolopoulos
Spiros Nikolopoulos
IKIoannis Kompatsiaris
Ioannis Kompatsiaris
Deep learning has recently gained popularity achieving state-of-the-art performance in tasks involving text, sound, or image processing. Due to its outstanding performance, there have been efforts to apply it in more challenging scenarios, for example, 3D data processing. This article surveys methods applying deep learning on 3D data and provides a classification based on how they exploit them. From the results of the examined works, we conclude that systems employing 2D views of 3D data typically surpass voxel-based (3D) deep models, which however, can perform better with more layers and severe data augmentation. Therefore, larger-scale datasets and increased resolutions are required.

16 May 2020 in Sensors
Verified
Journal Article
Open access
PDF file
Thanos StavropoulosThanos Stavropoulos
Thanos Stavropoulos
APAsterios Papastergiou
Asterios Papastergiou
Lampros MpaltadorosLampros Mpaltadoros
Lampros Mpaltadoros
Spiros NikolopoulosSpiros Nikolopoulos
Spiros Nikolopoulos
Ioannis KompatsiarisIoannis Kompatsiaris
Ioannis Kompatsiaris
The increasing ageing global population is causing an upsurge in ailments related to old age, primarily dementia and Alzheimer’s disease, frailty, Parkinson’s, and cardiovascular disease, but also a general need for general eldercare as well as active and healthy ageing. In turn, there is a need for constant monitoring and assistance, intervention, and support, causing a considerable financial and human burden on individuals and their caregivers. Interconnected sensing technology, such as IoT wearables and devices, present a promising solution for objective, reliable, and remote monitoring, assessment, and support through ambient assisted living. This paper presents a review of such solutions including both earlier review studies and individual case studies, rapidly evolving in the last decade. In doing so, it examines and categorizes them according to common aspects of interest such as health focus, from specific ailments to general eldercare; IoT technologies, from wearables to smart home sensors; aims, from assessment to fall detection and indoor positioning to intervention; and experimental evaluation participants duration and outcome measures, from acceptability to accuracy. Statistics drawn from this categorization aim to outline the current state-of-the-art, as well as trends and effective practices for the future of effective, accessible, and acceptable eldercare with technology.

31 January 2018 in Frontiers in Human Neuroscience
Verified
Journal Article
Open access
PDF file
Ioulietta LazarouIoulietta Lazarou
Ioulietta Lazarou
Spiros NikolopoulosSpiros Nikolopoulos
Spiros Nikolopoulos
PPPanagiotis C. Petrantonakis
Panagiotis C. Petrantonakis
IKIoannis Kompatsiaris
Ioannis Kompatsiaris
Magda TsolakiMagda Tsolaki
Magda Tsolaki
People with severe neurological impairments face many challenges in sensorimotor functions and communication with the environment; therefore they have increased demand for advanced, adaptive and personalized rehabilitation. During the last several decades, numerous studies have developed brain–computer interfaces (BCIs) with the goals ranging from providing means of communication to functional rehabilitation. Here we review the research on non-invasive, electroencephalography (EEG)-based BCI systems for communication and rehabilitation. We focus on the approaches intended to help severely paralyzed and locked-in patients regain communication using three different BCI modalities: slow cortical potentials, sensorimotor rhythms and P300 potentials, as operational mechanisms. We also review BCI systems for restoration of motor function in patients with spinal cord injury and chronic stroke. We discuss the advantages and limitations of these approaches and the challenges that need to be addressed in the future.

12 January 2018 in IEEE Intelligent Systems
Verified
Journal Article
Closed access
Kosmas DimitropoulosKosmas Dimitropoulos
Kosmas Dimitropoulos
FTFilareti Tsalakanidou
Filareti Tsalakanidou
Spiros NikolopoulosSpiros Nikolopoulos
Spiros Nikolopoulos
IKIoannis Kompatsiaris
Ioannis Kompatsiaris
NGNikos GRAMMALIDIS
Nikos GRAMMALIDIS
AMAthanasios Manitsaris
Athanasios Manitsaris
Intangible Cultural Heritage (ICH) creations include, amongst other, music, dance, singing, theatre, human skills, and craftsmanship. These cultural expressions are usually transmitted orally and/or using gestures and are modified over a period of time, through a process of collective recreation. As the world becomes more interconnected and many different cultures come into contact, local communities run the risk of losing important elements of their ICH, while young people find it difficult to maintain the connection with the cultural heritage treasured by their elders. In this paper, we present a novel holistic approach for the safeguarding and transmission of ICH that goes beyond the mere digitization of ICH content. Based on multisensory technology for the capturing of ICH, the proposed approach enables the generation of completely novel cultural content. High-level semantics are extracted from the acquired data, enabling researchers to identify possible implicit or hidden correlations between different ICH expressions or interpretation styles and study the evolution of a specific ICH. These data, coupled with other cultural resources, are accessible through the i-Treasures Web-platform, which provides the means for supporting knowledge exchange between researchers as well as know-how transmission from ICH bearers to apprentices.

1 June 2017
Verified
Conference Paper
Open access
VOVangelis P. Oikonomou
Vangelis P. Oikonomou
KGKostas Georgiadis
Kostas Georgiadis
GLGeorge Liaros
George Liaros
Spiros NikolopoulosSpiros Nikolopoulos
Spiros Nikolopoulos
IKIoannis Kompatsiaris
Ioannis Kompatsiaris
Brain-computer interfaces (BCIs) have been gaining momentum in making human-computer interaction more natural, especially for people with neuro-muscular disabilities. Among the existing solutions the systems relying on electroencephalograms (EEG) occupy the most prominent place due to their non-invasiveness. In this work, we provide a review of various existing techniques for the identification of motor imagery (MI) tasks. More specifically, we perform a comparison between Common Spatial Patterns (CSP) related features and features based on Power Spectral Density (PSD) techniques. Furthermore, for the identification of MI tasks, two well-known classifiers are used, the Linear Discriminant Analysis (LDA) and the Support Vector Machines (SVM). Our results confirm that PSD features demonstrate the most consistent robustness and effectiveness in extracting patterns for accurately discriminating between left and right MI tasks.

17 May 2021 in Frontiers in Neuroergonomics
Verified
Journal Article
Open access
PDF file
FKFotis Kalaganis
Fotis Kalaganis
KGKostas Georgiadis
Kostas Georgiadis
VOVangelis Oikonomou
Vangelis Oikonomou
NLNikos A. Laskaris
Nikos A. Laskaris
Spiros NikolopoulosSpiros Nikolopoulos
Spiros Nikolopoulos
Ioannis KompatsiarisIoannis Kompatsiaris
Ioannis Kompatsiaris
Fueled by early success stories, the neuromarketing domain advanced rapidly during the last 10 years. As exciting new techniques were being adapted from medical research to the commercial domain, many neuroscientists and marketing practitioners have taken the chance to exploit them so as to uncover the answers of the most important marketing questions. Among the available neuroimaging technologies, electroencephalography (EEG) stands out as the less invasive and most affordable method. While not equally precise as other neuroimaging technologies in terms of spatial resolution, it can capture brain activity almost at the speed of cognition. Hence, EEG constitutes a favorable candidate for recording and subsequently decoding the consumers' brain activity. However, despite its wide use in neuromarketing, it cannot provide the complete picture alone. In order to overcome the limitations imposed by a single monitoring method, researchers focus on more holistic approaches. The exploitation of hybrid EEG schemes (e.g., combining EEG with eye-tracking, electrodermal activity, heart rate, and/or other) is ever growing and will hopefully allow neuromarketing to uncover consumers' behavior. Our survey revolves around last-decade hybrid neuromarketing schemes that involve EEG as the dominant modality. Beyond covering the relevant literature and state-of-the-art findings, we also provide future directions on the field, present the limitations that accompany each of the commonly employed monitoring methods and briefly discuss the omni-present ethical scepticizm related to neuromarketing.