Papers by Vasilis Tsakanikas
2020 42nd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC)
In this study, we propose a dynamic Bayesian network (DBN)-based approach to behavioral modelling... more In this study, we propose a dynamic Bayesian network (DBN)-based approach to behavioral modelling of community dwelling older adults at risk for falls during the daily sessions of a hologram-enabled vestibular rehabilitation therapy programme. The component of human behavior being modelled is the level of frustration experienced by the user at each exercise, as it is assessed by the NASA Task Load Index. Herein, we present the topology of the DBN and test its inference performance on real-patient data. Clinical Relevance-Precise behavioral modelling will provide an indicator for tailoring the rehabilitation programme to each individual's personal psychological needs. I. INTRODUCTION More than 1/3 of the population over 40 years old faces some kind of vestibular disorder leading, in most cases, to dizziness and imbalance [1]. Benign paroxysmal positional vertigo (BPPV) is the most commonly reported vestibular disorder accounted for approximately half of cases [2]. Vestibular Rehabilitation Therapy (VRT) has been shown to be very effective for persons suffering from dizziness and balance impairments; VRT decreases duration and intensity of symptoms (e.g. dizziness and postural instability) and lessens the number of falls and fear of falling [3-5]. During supervised, home-based VRT, behavioral outcomes, such as enjoyment and adherence, are associated with interpersonal behaviors psychological needs (i.e. satisfaction and frustration) [6]. According to the NASA Task Load Index (TLX), the subjective workload one individual perceives during his/her interaction with various human-machine interface systems can be defined as a combination of: (i) the mental demand, (ii) the physical demand, (iii) the temporal demand, (iv) the performance, (v) the effort, and (v) the frustration [7, 8]. In
Diagnostics, 2021
Carotid artery disease is considered a major cause of strokes and there is a need for early disea... more Carotid artery disease is considered a major cause of strokes and there is a need for early disease detection and management. Although imaging techniques have been developed for the diagnosis of carotid artery disease and different imaging-based markers have been proposed for the characterization of atherosclerotic plaques, there is still need for a definition of high-risk plaques in asymptomatic patients who may benefit from surgical intervention. Measurement of circulating biomarkers is a promising method to assist in patient-specific disease management, but the lack of robust clinical evidence limits their use as a standard of care. The purpose of this review paper is to present circulating biomarkers related to carotid artery diagnosis and prognosis, which are mainly provided by statistical-based clinical studies. The result of our investigation showed that typical well-established inflammatory biomarkers and biomarkers related to patient lipid profiles are associated with carot...
BACKGROUND Balance rehabilitation programs constitute the most common treatment for balance disor... more BACKGROUND Balance rehabilitation programs constitute the most common treatment for balance disorders. Nonetheless, lack of resources and of highly expert physiotherapists barriers for patients to have individualized rehabilitation sessions and the required in person monitoring of the rehabilitation program. Therefore, balance rehabilitation programs are often transferred to the home environment, with a high risk of the patient mis-performing the exercises or failing to follow the programme at all. OBJECTIVE Holobalance is a persuasive coaching system with the capacity to offer full-scale rehabilitation services at home. Holobalance comprises of several modules, from rehabilitation program management to Augmented Reality (AR) coach presentation. One of the modules is the scoring module, which assesses the performance of the patient using wearable devices. METHODS The data-driven scoring module described in the present work is based on an extensive dataset (~1300 rehabilitation exerc...
Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 2022
The Multimedia Broadcast/Multicast Service (MBMS) was designed to enable the mass distribution of... more The Multimedia Broadcast/Multicast Service (MBMS) was designed to enable the mass distribution of multimedia content in 3rd Generation and beyond cellular networks. If such services are to become commercially viable, they must be able to efficiently support widely heterogeneous user requirements, for example, due to terminal limitations and cost constraints. This paper presents an MBMS extension that allows multiple variants of the same content to be economically distributed to heterogeneous receivers, explicitly taking into account the possibility of using either dedicated or common radio channels. We describe our extended multiple content variant MBMS model by explaining the modifications that it imposes on the standard MBMS model, as well as the manner in which it can be combined with layered coding. We also present an analytical evaluation of our approach against alternatives based on the standard MBMS in terms of control and user plane overhead, and compare the analytical predictions with detailed simulation results. Both the analysis and the simulations indicate that our proposal can indeed satisfy heterogeneous user requirements, while consuming considerably lower resources than the standard-based alternatives.
8th European Medical and Biological Engineering Conference, 2020
Carotid artery disease is considered as the pathological disease of carotid arteries and is consi... more Carotid artery disease is considered as the pathological disease of carotid arteries and is considered as a principal cause of stroke. Therefore, early diagnosis of carotid artery disease is of high clinical importance. This study aims to present an overall methodology for the accurate identification of the inner wall, outer wall and the atherosclerotic plaques (calcified and non-calcified) of the carotid arteries. The proposed methodology is based on a level set based approach, which is fully adapted in each computed tomography acquisition protocol. Briefly, the methodology includes the following steps: (i) the estimation of intensity membership functions for the inner wall, the outer wall and CP, (ii) the carotid artery centerline extraction, (iii) the inner wall, outer wall and calcified plaques segmentation, (iv) the noncalcified plaques segmentation and finally (v) the 3D models construction. The segmentation accuracy of the proposed methodology has been validated against manual expert's annotations in 4 patients, and more specifically in 300 computed tomography angiography slices for the inner wall segmentation and in 30 slices as far as the atherosclerotic plaques is concerned. The utilized evaluation metrics were the Dice coefficient and the Hausdorff Distance and our very first results are promising for the accurate and automated segmentation of carotid arteries.
Proceedings of the 20th Annual International Conference on Digital Government Research, 2019
Within this report, the architecture of a system named PODS (Public On-Line Deliberation System) ... more Within this report, the architecture of a system named PODS (Public On-Line Deliberation System) is presented and detailed. PODS allows both decision makers (also called authority) and citizens to propose a theme for deliberation and results in a winning proposal about an issue, along with the relative deliberation analytics. The system supports the upload of a deliberation theme, proposal setting and an iterative process, which leads to the formulation of the winning proposal. The whole process is transparent to public through rating and publication and take into account political analytics.
Background: In practice, e-democracy is based on two pillarsone is e-participation and the other ... more Background: In practice, e-democracy is based on two pillarsone is e-participation and the other is e-voting. The development of e-government is a major technological achievement allowing citizens to participate equally in the political process. E-government and E-Participation, as a part of e-democracy, encompass social, economic and cultural conditions that enable the free and equal practice of political self-determination. Information and Communications Technology can be a powerful tool to increase the quality of public policy, citizens understanding of public policy issues and their participation in government policy making. International Relevance: According to the Government Online International Network, governments around the globe are actively promoting online consultations in order to strengthen democracy and development (Poland, 2001). Yet, a major citizens' concern about the usage of e-democracy tools, and more specifically, e-deliberation apparatuses is data security and confidentiality. Within a process of expressing political opinions, citizens need to be reassured that the collected data will only be used for the intended purposes and the possibility of data leakage will be minimized. While mainstream technology (firewalls, encrypted databases, etc.) can provide quite a substantial level of security, data confidentiality issues arise every day. Aim: The aim of this paper is to report on the first phase of an ongoing research aimed at designing, developing and testing an e-deliberation tool. This first phase represents the collection of experts' opinions for the design of an e-deliberation tool through literature review, survey with experts and expert group workshops. We present the operationalization of a series of criteria for e-deliberation tool comparison. This operationalization will be used to build a questionnaire for experts in the field of e-deliberation and to guide data collection though a series of expert group workshops. Methodology: A review of the literature has been performed in order to select relevant criteria and variables which will be used to build a questionnaire for experts in the field of e-deliberation. We report on the operationalization of these variables and criteria. Impact: The results of this research will be used to further inform e-deliberation tool development.
In this study, we propose a dynamic Bayesian network (DBN)-based approach to behavioral modelling... more In this study, we propose a dynamic Bayesian network (DBN)-based approach to behavioral modelling of community dwelling older adults at risk for falls during the daily sessions of a hologram-enabled vestibular rehabilitation therapy programme. The component of human behavior being modelled is the level of frustration experienced by the user at each exercise, as it is assessed by the NASA Task Load Index. Herein, we present the topology of the DBN and test its inference performance on real-patient data. Clinical Relevance— Precise behavioral modelling will provide an indicator for tailoring the rehabilitation programme to each individual’s personal psychological needs.
2020 IEEE Computer Society Annual Symposium on VLSI (ISVLSI), 2020
The goal of the SMART4ALL EU funded project is to build capacity amongst European stakeholders vi... more The goal of the SMART4ALL EU funded project is to build capacity amongst European stakeholders via the development of selfsustained, cross-border experiments that transfer knowledge and technology between academia and industry. It targets Customized Low Energy Computing (CLEC) in the Cyber-Physical (CPS) and the Internet of Things (IoT) domains by combining a set of unique characteristics that join together different cultures, different policies, different geographical areas, and different application domains. The SMART4ALL vision will be realized mainly through funded (via open calls) Pathfinder Application Experiments (PAEs) that will enable the transformation of academic knowledge into industry especially targeting South and Eastern European countries that are currently underrepresented in European funding opportunities. In this way community building, strategy development, and ecosystem learning are envisioned for boosting high-quality research and development in South Eastern Europe (SEE), through an efficient combination of regional, national and European policies. Furthermore SMART4ALL sets forward the concept of marketplace which is offered as a service (Marketplace-as-a-Service or MaaS) that acts as one-stop-smart-stop by offering tools, services, platforms based mainly on open sources technologies as well as technology suppliers - adopter matchmaking capabilities customized to the targeted thematic pillars of the project.
ICC 2021 - IEEE International Conference on Communications
This paper introduces a novel distributed AI model for managing in real-time, edge based intellig... more This paper introduces a novel distributed AI model for managing in real-time, edge based intelligent analytics, such as the ones required for smart video surveillance. The novelty relies on distributing the applications in several decomposed functions which are linked together, creating virtual chain functions, where both computational and communication limitations are considered. Both theoretical analysis and simulation analysis in a real-case scenario have shown that the proposed model can enable real-time surveillance analytics on a low-cost edge network. Finally, a caching mechanism is proposed and evaluated, reducing further the operational costs of the edge network.
Studies in health technology and informatics, 2016
The development of platforms that are able to continuously monitor and handle epileptic seizures ... more The development of platforms that are able to continuously monitor and handle epileptic seizures in a non invasive manner is of great importance as they would improve the quality of life of drug resistant epileptic patients. In this work, a device and a computational platform is presented for acquiring low noise electroencephalographic signals, for the detection/prediction of epileptic seizures and the storage of ictal activity in an electronic personal health record. In order to develop this platform, a systematic clinical protocol was established including a number of drug resistant children from the University Hospital of Heraklion. Dry electrodes with innovative micro-spike design were proposed in order to increase the signal to noise ratio of the recorded EEG signals. A wearable low cost platform and its corresponding wireless communication protocol was developed focus on minimizing the interference with the patient's body. A computational subsystem with advanced algorithms...
Advanced Topics in Scattering Theory and Biomedical Engineering - 9th International Workshop on Mathematical Methods in Scattering Theory and Biomedical Engineering, 2010
2010 Annual International Conference of the IEEE Engineering in Medicine and Biology, 2010
The paper proposes a novel Extensible Markup Language (XML) based format called ART-ML that aims ... more The paper proposes a novel Extensible Markup Language (XML) based format called ART-ML that aims at supporting the interoperability and the reuse of models of blood flow, mass transport and plaque formation, exported by ARTool. ARTool is a platform for the automatic processing of various image modalities of coronary and carotid arteries. The images and their content are fused to
Proceedings of the 10th IEEE International Conference on Information Technology and Applications in Biomedicine, 2010
The goal of the this clinical project is to create a virtual model for atherogenesis and plaque p... more The goal of the this clinical project is to create a virtual model for atherogenesis and plaque progression. This model will result from the integration of molecular, cellular, haemodynamic and morphological factors. The model will permit a better understanding of the pathophysiological mechanisms related to atherosclerosis, and it will aid in the choice of the best therapeutic solution for patients.
Proceedings of the 10th IEEE International Conference on Information Technology and Applications in Biomedicine, 2010
Abstract Atherosclerosis is the most prevalent cardiovascular disease which affects millions of p... more Abstract Atherosclerosis is the most prevalent cardiovascular disease which affects millions of people globally each year. The development of atheroma is directly connected to the interaction of blood flow with the arterial wall. Therefore, the modeling of this interaction is ...
BACKGROUND: Intravascular ultrasound (IVUS) is an invasive imaging modality that provides high re... more BACKGROUND: Intravascular ultrasound (IVUS) is an invasive imaging modality that provides high resolution crosssectional images permitting detailed evaluation of the lumen, outer vessel wall and plaque morphology and evaluation of its composition. Over the last years several methodologies have been proposed which allow automated processing of the IVUS data and reliable segmentation of the regions of interest or characterization of the type of the plaque. OBJECTIVE: In this paper we present a novel methodology for the automated identification of different plaque components in grayscale IVUS images. METHODS: The proposed method is based on a hybrid approach that incorporates both image processing techniques and classification algorithms and allows classification of the plaque into three different categories: Hard Calcified, Hard-Non Calcified and Soft plaque. Annotations by two experts on 8 IVUS examinations were used to train and test our method. RESULTS: The combination of an automatic thresholding technique and active contours coupled with a Random Forest classifier provided reliable results with an overall classification accuracy of 86.14%. CONCLUSIONS: The proposed method can accurately detect the plaque using grayscale IVUS images and can be used to assess plaque composition for both clinical and research purposes.
Revista Brasileira de Engenharia Biomédica, 2014
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Papers by Vasilis Tsakanikas