Publications

BibTeX Entry:

@Article{electronics14204053,
AUTHOR = {Thomatos, Evangelos and Sgora, Aggeliki and Tsipis, Athanasios and Chatzimisios, Periklis},
TITLE = {AI Methods in Network Slice Life-Cycle Phases: A Survey},
JOURNAL = {Electronics},
VOLUME = {14},
YEAR = {2025},
NUMBER = {20},
ARTICLE-NUMBER = {4053},
URL = {https://www.mdpi.com/2079-9292/14/20/4053},
ISSN = {2079-9292},
ABSTRACT = {Network slicing (NS) plays a vital role in enabling flexible and efficient resource allocation, tailored to diverse use cases and network domains. This survey paper explores the synergy between NS and Artificial Intelligence (AI), emphasizing how Machine Learning (ML) techniques can address challenges across the slice life-cycle. A key contribution of this work is an in-depth analysis of AI and primarily ML applications in each phase of the slice life-cycle, delving into their specific tasks and discussing the techniques applied to these tasks. Furthermore, we present a taxonomy based on different slicing criteria, offering a structured perspective to enhance understanding and implementation.},
DOI = {https://doi.org/10.3390/electronics14204053}

BibTeX Entry:

@Article{technologies12100196,
AUTHOR = {Komianos, Vasileios and Tsipis, Athanasios and Kontopanagou, Katerina},
TITLE = {Introducing Digitized Cultural Heritage to Wider Audiences by Employing Virtual and Augmented Reality Experiences: The Case of the v-Corfu Project},
JOURNAL = {Technologies},
VOLUME = {12},
YEAR = {2024},
NUMBER = {10},
ARTICLE-NUMBER = {196},
URL = {https://www.mdpi.com/2227-7080/12/10/196},
ISSN = {2227-7080},
ABSTRACT = {In recent years, cultural projects utilizing digital applications and immersive technologies (VR, AR, MR) have grown significantly, enhancing cultural heritage experiences. Research emphasizes the importance of usability, user experience, and accessibility, yet holistic approaches remain underexplored and many projects fail to reach their audience. This article aims to bridge this gap by presenting a complete workflow including systematic requirements analysis, design guidelines, and development solutions based on knowledge extracted from previous relevant projects. The article focuses on virtual museums covering key challenges including compatibility, accessibility, usability, navigation, interaction, computational performance and graphics quality, and provides a design schema for integrating virtual museums into such projects. Following this approach, a number of applications are presented. Their performance with respect to the aforementioned key challenges is evaluated. Users are invited to assess them, providing positive results. To assess the virtual museum’s ability to attract a broader audience beyond the usual target group, a group of underserved minorities are also invited to use and evaluate it, generating encouraging outcomes. Concluding, results show that the presented workflow succeeds in yielding high-quality applications for cultural heritage communication and attraction of wider audiences, and outlines directions for further improvements in digitized heritage applications.},
DOI = {https://doi.org/10.3390/technologies12100196}}

Bibtex Entry:

@article{kontopanagou2024fostering,
title = {Fostering Cultural Awareness in Museums and Monuments by Employing Extended Reality},
journal = {Global Journal of Archaeology and Anthropology},
volume = {13},
number =  {4},
article number = {555870},
year = {2024},
doi = {http://dx.doi.org/10.19080/GJAA.2024.13.555870},
url = {https://juniperpublishers.com/gjaa/GJAA.MS.ID.555870.php},
author = {Kontopanagou, Katerina and Tsipis, Athanasios and Komianos, Vasileios},
keywords = {Cultural Awareness, Museums, Monuments, Digital Culture, Extended Reality},
abstract = {Fostering cultural awareness and user engagement in museums and monuments is fundamental for the successful promotion and valorization of Cultural Heritage. The current work aims at a brief discussion about the possibilities and benefits brought forth by the adoption of immersive technologies such as Virtual, Augmented and Mixed Reality, often jointly termed as Extended Reality (XR), in boosting user engagement and providing meaningful and long-lasting cultural experiences that ensure inclusivity and accessibility to all.}}

Bibtex Entry:

@article{tsipis2022towards,
title = {Towards fairness and QoE-based edge allocation for multiplayer virtual reality applications in edge computing},
journal = {ITU Journal on Future and Evolving Technologies},
volume = {3},
issue =  {3},
pages = {854-873},
year = {2022},
doi = {https://doi.org/10.52953/VAVY1919},
url = {https://www.itu.int/pub/S-JNL-VOL3.ISSUE3-2022-A62},
author = {Tsipis, Athanasios and Komianos, Vasileios and Oikonomou, Konstantinos and Stavrakakis, Ioannis},
keywords = {Edge computing, fairness, quality of experience, user edge allocation, virtual reality},
abstract = {Edge computing has emerged as the next big thing in distributed computing, by extending the cloud paradigm and offering efficient ways to engage with latency-intolerant applications, such as Virtual Reality (VR) multiplayer games. In edge computing, the service providers can benefit from existing cellular infrastructure to deploy services on edge servers that reside in close proximity to the users. Given the limited available budget for edge resource investment, one fundamental problem that manifests is the discovery of a prudent edge allocation strategy, that will efficiently prescribe which users are assigned to which edge servers, in order to tackle application-specific requirements, like minimizing system deployment costs. In this paper, considering the frequent interactions and view inconsistencies occurring among multiple users immersed in the same VR game, we address the problem from the users' perspective, focusing on improving their edge admission rate, resource provisioning and overall fairness, in order to subsequently maximize the average Quality of Experience (QoE). We call this the "Fairness and QoE-Based Edge Allocation" (FQEA) problem, formally formulating its properties and theoretically proving its complexity. However, discovering optimal solutions to the NP-hard FQEA in large-scale VR scenarios is challenging. Hence, we propose FQEA-H, a heuristic algorithm to generate allocation strategies in reasonable time. Comprehensive simulations, conducted on a real-world topological trace, demonstrate how FQEA-H can tackle the problem effectively, generally outperforming both the baseline and state-of-the-art alternatives.}}

Bibtex Entry:

@article{TSIPIS2022109028,
title = {Joint optimization of social interactivity and server provisioning for interactive games in edge computing},
journal = {Computer Networks},
volume = {212},
pages = {109028},
year = {2022},
issn = {1389-1286},
doi = {https://doi.org/10.1016/j.comnet.2022.109028},
url = {https://www.sciencedirect.com/science/article/pii/S1389128622001840},
author = {Athanasios Tsipis and Konstantinos Oikonomou},
keywords = {Cost optimization, Facility location, Mobile edge computing, Player assignment, Server provisioning, Social interactivity},
abstract = {Distributed interactive applications (DIAs), like immersive virtual reality and multiplayer cloud games, where players team-up and form social communities to participate in collaborative virtual events, dominate the modern cloud multimedia industry. Still, due to the massive workload, intensive graphics processing and delay intolerance, conventional cloud-only models are increasingly becoming ineffective. Thankfully, with the shift towards Mobile Edge Computing, game providers can leverage existing cellular infrastructure to deploy edge servers that supply gaming services in a highly accessible fashion. One fundamental challenge, that naturally arises, is the discovery of the most suitable player-to-edge server assignment strategy, that achieves a balanced trade-off between conflicting objectives that refer to high social interactivity on the one hand and low-cost server provisioning on the other. In this article, the core properties of social interactivity for gaming DIAs are investigated through formal formulation under diverse social aspects and strict assignment rules, respecting, in the meantime, the provisioning cost and constraints of the edge servers. We call this the “Social Interactivity-oriented Edge Allocation” (SIEA) problem and prove its NP-hardness. Based on our theoretical analysis, we present SIEA-H, a two-phase heuristic algorithm to efficiently assign players to servers and then iteratively refine the edge allocation strategy. SIEA-H is evaluated using comprehensive trace-driven simulations. The results demonstrate how it surpasses the baseline and state-of-the-art assignment alternatives in reducing the total cost, especially as the number of servers and their capacity grows, or the coverage area expands, while for players it exhibits the highest admission rate and the best overall resource management.}}

Bibtex Entry:

@article{tsipis2021arpa,
author = {Tsipis, Athanasios and Oikonomou, Konstantinos},
title = {ARPA: An autonomous renderer placement algorithm in distributed multimedia fog networks with delay guarantees},
journal = {ITU Journal on Future and Evolving Technologies},
volume = {2},
number = {2},
year = {2021},
pages = {81-108},
numpages = {28},
url = {https://www.itu.int/pub/S-JNL-VOL2.ISSUE2-2021-A06},
doi = {https://doi.org/10.52953/TSDT6782},
keywords = {Delay guarantees, distributed facility location, fog computing networks, multimedia cloud computing, rendering server placement, scalability},
abstract = {Multimedia cloud computing has emerged as a popular paradigm for the support of delay-intolerable immersive multimedia applications with high-end three-dimensional rendering. To that end, fog computing offers distributed computational offloading solutions, by positioning rendering servers in close proximity to end users promising in this way continuous service provision, that is otherwise not easily attainable under the strictly centralized cloud-only model. Yet, in order to alleviate the multimedia providers from unnecessary capital expenditure, a strategic placement approach of the servers at the fog layer must be implemented, that can effectively cope both with the network dynamics and the overall imposed deployment cost, and still adhere to the delay bounds set forth by the multimedia application. In this paper, we formally formulate the problem as a facility location problem using constrained optimization over a finite time horizon. We then theoretically analyze the minimum acceptable conditions necessary for a decentralized location of the servers, utilizing solely local information around their immediate neighborhood, that iteratively leads to better solutions. Based on the analysis, we propose a distributed algorithm, namely the Autonomous Renderer Placement Algorithm (ARPA), to address it. ARPA employs localized service relocation to shift the placement according to simple rules that designate elastic migration, replication, and complementary consolidation of the underlying renderers. Simulation results under diversified deployment scenarios, as well as trace-driven comparisons against other approaches, testify to ARPA`s accountability in obeying the delay limits and fast converge in finite time slots to a placement solution that both outperforms the baseline alternatives and is close to the optimal one, rendering it suitable for scaling up and down to meet the current demands of the offered multimedia applications.}}

BibTeX Entry:

@Article{technologies9030057,
AUTHOR = {Kontopanagou, Katerina and Tsipis, Athanasios and Komianos, Vasileios},
TITLE = {A Framework for Exploring Churches/Monuments/Museums of Byzantine Cultural Influence Exploiting Immersive Technologies in Real-Time Networked Environments},
JOURNAL = {Technologies},
VOLUME = {9},
YEAR = {2021},
NUMBER = {3},
ARTICLE-NUMBER = {57},
URL = {https://www.mdpi.com/2227-7080/9/3/57},
ISSN = {2227-7080},
ABSTRACT = {The unique art that was developed in Byzantine times is widely accepted as a precursor to the Renaissance and is still evident in monuments either from or influenced by the Byzantium. Visiting such a site is a unique experience due to the lavishly painted interior for both tourists and scholars. Taking advantage of the emerging 5G technologies, cloud/fog computing, and Augmented/Mixed Reality mechanisms, a common smart device (e.g., smartphone, tablet) could be employed to give a better experience to the end-users. The proposed framework is intended to provide visitors with interpretative information regarding the visited monuments and their paintings. Under the framework introduced in this paper, camera input is uploaded to a cloud/fog computing infrastructure where appropriate algorithms and services provide monument and painting recognition and the mobile application retrieves and projects the related information. In addition, the designed immersive user interfaces assist visitors in contributing in cases of monuments and paintings for which no available information exists. This paper presents the state of the art in approaches for immersive experiences in Digital Culture, reviews the current image recognition approaches and their suitability for Byzantine paintings, proposes interaction techniques appropriately designed for observation and interaction of paintings, and discusses the overall framework architecture that is needed to support the described functionality while stressing the challenging issues of the above aspects thus paving the road for future work and providing guidelines for a test-bed implementation.},
DOI = {https://doi.org/10.3390/technologies9030057}}

BibTeX Entry:

@Article{en13143693,
AUTHOR = {Tsipis, Athanasios and Papamichail, Asterios and Angelis, Ioannis and Koufoudakis, George and Tsoumanis, Georgios and Oikonomou, Konstantinos},
TITLE = {An Alertness-Adjustable Cloud/Fog IoT Solution for Timely Environmental Monitoring Based on Wildfire Risk Forecasting},
JOURNAL = {Energies},
VOLUME = {13},
YEAR = {2020},
NUMBER = {14},
ARTICLE-NUMBER = {3693},
URL = {https://www.mdpi.com/1996-1073/13/14/3693},
ISSN = {1996-1073},
ABSTRACT = {Internet of Things (IoT) appliances, especially those realized through wireless sensor networks (WSNs), have been a dominant subject for heavy research in the environmental and agricultural sectors. To address the ever-increasing demands for real-time monitoring and sufficiently handle the growing volumes of raw data, the cloud/fog computing paradigm is deemed a highly promising solution. This paper presents a WSN-based IoT system that seamlessly integrates all aforementioned technologies, having at its core the cloud/fog hybrid network architecture. The system was intensively validated using a demo prototype in the Ionian University facilities, focusing on response time, an important metric of future smart applications. Further, the developed prototype is able to autonomously adjust its sensing behavior based on the criticality of the prevailing environmental conditions, regarding one of the most notable climate hazards, wildfires. Extensive experimentation verified its efficiency and reported on its alertness and highly conforming characteristics considering the use-case scenario of Corfu Island’s 2019 fire risk severity. In all presented cases, it is shown that through fog leveraging it is feasible to contrive significant delay reduction, with high precision and throughput, whilst controlling the energy consumption levels. Finally, a user-driven web interface is highlighted to accompany the system; it is capable of augmenting the data curation and visualization, and offering real-time wildfire risk forecasting based on Chandler’s burning index scoring.},
DOI = {https://doi.org/10.3390/en13143693}}

BibTeX Entry:

@article{SKIADOPOULOS2020102220,
title = {Impact of drone route geometry on information collection in wireless sensor networks},
journal = {Ad Hoc Networks},
volume = {106},
pages = {102220},
year = {2020},
issn = {1570-8705},
doi = {https://doi.org/10.1016/j.adhoc.2020.102220},
url = {https://www.sciencedirect.com/science/article/pii/S1570870519310935},
author = {Konstantinos Skiadopoulos and Konstantinos Giannakis and Athanasios Tsipis and Konstantinos Oikonomou and Ioannis Stavrakakis},
keywords = {Drones, Wireless sensor networks, Information collection, Route shape, Internet of things, Soft geometric random graphs},
abstract = {The recent technological evolution of drones along with the constantly growing maturity of its commercialization, has led to the emergence of novel drone-based applications within the field of wireless sensor networks for information collection purposes. In such settings, especially when deployed in outdoor environments with limited external control, energy consumption and robustness are challenging problems for the system’s operation. In the present paper, a drone-assisted wireless sensor network is studied, the aim being to coordinate the routing of information (among the ground nodes and its propagation to the drone), investigating several drone trajectories or route shapes and examining their impact on information collection (the aim being to minimize transmissions and consequently, energy consumption). The main contribution lies on the proposed algorithms that coordinate the communication between (terrestrial) sensor nodes and the drone that may follow different route shapes. It is shown through simulations using soft random geometric graphs that the number of transmitted messages for each drone route shape depends on the rotational symmetry around the center of each shape. An interesting result is that the higher the order of symmetry, the lower the number of transmitted messages for data collection. Contrary, for those cases that the order of symmetry is the same, even for different route shapes, similar number of messages is transmitted. In addition to the simulation results, an experimental demonstration, using spatial data from grit bin locations, further validates the proposed solution under real-world conditions, demonstrating the applicability of the proposed approach.}}

BibTeX Entry:

@Article{agriculture10030089,
AUTHOR = {Zervopoulos, Alexandros and Tsipis, Athanasios and Alvanou, Aikaterini Georgia and Bezas, Konstantinos and Papamichail, Asterios and Vergis, Spiridon and Stylidou, Andreana and Tsoumanis, Georgios and Komianos, Vasileios and Koufoudakis, George and Oikonomou, Konstantinos},
TITLE = {Wireless Sensor Network Synchronization for Precision Agriculture Applications},
JOURNAL = {Agriculture},
VOLUME = {10},
YEAR = {2020},
NUMBER = {3},
ARTICLE-NUMBER = {89},
URL = {https://www.mdpi.com/2077-0472/10/3/89},
ISSN = {2077-0472},
ABSTRACT = {The advent of Internet of Things has propelled the agricultural domain through the integration of sensory devices, capable of monitoring and wirelessly propagating information to producers; thus, they employ Wireless Sensor Networks (WSNs). These WSNs allow real time monitoring, enabling intelligent decision-making to maximize yields and minimize cost. Designing and deploying a WSN is a challenging and multivariate task, dependent on the considered environment. For example, a need for network synchronization arises in such networks to correlate acquired measurements. This work focuses on the design and installation of a WSN that is capable of facilitating the sensing aspects of smart and precision agriculture applications. A system is designed and implemented to address specific design requirements that are brought about by the considered environment. A simple synchronization scheme is described to provide time-correlated measurements using the sink node’s clock as reference. The proposed system was installed on an olive grove to assess its effectiveness in providing a low-cost system, capable of acquiring synchronized measurements. The obtained results indicate the system’s overall effectiveness, revealing a small but expected difference in the acquired measurements’ time correlation, caused mostly by serial transmission delays, while yielding a plethora of relevant environmental conditions.},
DOI = {https://doi.org/10.3390/agriculture10030089}}

BibTeX Entry:

@Article{smartcities3010008,
AUTHOR = {Vergis, Spiridon and Komianos, Vasileios and Tsoumanis, Georgios and Tsipis, Athanasios and Oikonomou, Konstantinos},
TITLE = {A Low-Cost Vehicular Traffic Monitoring System Using Fog Computing},
JOURNAL = {Smart Cities},
VOLUME = {3},
YEAR = {2020},
NUMBER = {1},
PAGES = {138--156},
URL = {https://www.mdpi.com/2624-6511/3/1/8},
ISSN = {2624-6511},
ABSTRACT = {With the rapid increase of vehicles in use worldwide, the need for efficient traffic monitoring systems has arisen. This work proposes a low-cost vehicular traffic monitoring system using IoT devices and fog computing. The system is based on a three-tiered architecture which is composed of (i) the mobile tracking system that records the positions of the vehicles using GPS technologies; (ii) the information gathering system which gathers all the data collected by the mobile tracking system; and (iii) the fog devices that process the data collected and extract the information needed. The system is tested in the town of Corfu during a period of increased tourism when the traffic is considered to be relatively dense. The mobile tracking system devices are placed on taxis and with the help of professional taxi drivers the accuracy of the data collected is evaluated. The system is able to record the movement of the vehicles accurately using its own independent data. The results can be remotely accessed by utilizing fog and cloud computing infrastructure established to process the data and upload it on a server. The system is used to give a better understanding of the speed variance in the center of the town during different dates and hours. In conclusion the system presented in this study can be utilized to monitor the traffic and provide vital information about its behavior in relation to time.},
DOI = {https://doi.org/10.3390/smartcities3010008}}

BibTeX Entry:

@Article{electronics9030454,
AUTHOR = {Alvanou, Aikaterini Georgia and Zervopoulos, Alexandros and Papamichail, Asterios and Bezas, Konstantinos and Vergis, Spiridon and Stylidou, Andreana and Tsipis, Athanasios and Komianos, Vasileios and Tsoumanis, Georgios and Koufoudakis, George and Oikonomou, Konstantinos},
TITLE = {CaBIUs: Description of the Enhanced Wireless Campus Testbed of the Ionian University},
JOURNAL = {Electronics},
VOLUME = {9},
YEAR = {2020},
NUMBER = {3},
ARTICLE-NUMBER = {454},
URL = {https://www.mdpi.com/2079-9292/9/3/454},
ISSN = {2079-9292},
ABSTRACT = {Technological evolution and in particular the development of the Internet of Things (IoT) has paved the way for material prosperity and a better standard of living. A critical factor in the effectiveness of emerging IoT applications, which heavily rely on sensor information flow, is the development of a functional and efficient Wireless Sensor Network. Additionally, the levels of automation are conducive to usability and time efficiency by reducing the need for human intervention, as well as increasing the rate at which experiments can be carried out. In current work, an already installed infrastructure on the Ionian University campus is considered and enhanced, with the goal of elevating accessibility and user-friendliness, by designing a web platform. The presented platform enables the remote development, execution and monitoring of simple but necessary network-based algorithms using a custom language, without requiring code to be uploaded to remote nodes. As a proof of concept, three information dissemination algorithms are implemented and provided as example templates for users, promoting simultaneously ease of use.},
DOI = {https://doi.org/10.3390/electronics9030454}}

BibTeX Entry:

@Article{agriengineering2010011,
AUTHOR = {Tsipis, Athanasios and Papamichail, Asterios and Koufoudakis, George and Tsoumanis, Georgios and Polykalas, Spyros E. and Oikonomou, Konstantinos},
TITLE = {Latency-Adjustable Cloud/Fog Computing Architecture for Time-Sensitive Environmental Monitoring in Olive Groves},
JOURNAL = {AgriEngineering},
VOLUME = {2},
YEAR = {2020},
NUMBER = {1},
PAGES = {175--205},
URL = {https://www.mdpi.com/2624-7402/2/1/11},
ISSN = {2624-7402},
ABSTRACT = {The emerging and vast adoption of the Internet of Things (IoT) has sprung a plethora of research works regarding the potential benefits in smart agriculture. A popular implementation involves the deployment of Wireless Sensor Networks (WSNs), which embed low energy consumption sensory nodes to capture the critical environmental parameters prevailing on the farms. However, to manage the ever-increasing volumes of raw data successfully, new approaches must be explored. Under this scope, current work reports on the design and development of an IoT system, having in mind the case of olive groves, which are considered the dominant sector for agricultural activity in the Mediterranean Basin. The system incorporates the cloud/fog computing paradigm to equip the olive growers with a low-cost solution for accurate, reliable, and almost real-time monitoring of their crops. Its core is based on a three-layered network architecture, capable of dynamically balancing the generated load, by pushing cloud-elastic resources to the underlying fog network. As such, the premise of the approach lies in the conforming character of the system that allows for targeted alterations to its operational functionality to meet stringent latency and traffic load environmental monitoring constraints. To evaluate the performance of the proposed architecture, a demo prototype is developed and deployed in the facilities of the Ionian University. Experimental results illustrate the efficiency, flexibility, and scalability of the approach in terms of latency, achieving response time reduction across all platforms, a subject of the utmost importance when it comes to precision agriculture of the future. Moreover, it is shown that the system is capable of dynamic functionality adaptation, to meet network traffic load constraints, achieving high throughput (on average 95%) and addressing potential environmental dangers to olive oil production.},
DOI = {https://doi.org/10.3390/agriengineering2010011}}

BibTeX Entry:

@article{SKIADOPOULOS201947,
title = {Synchronization of data measurements in wireless sensor networks for IoT applications},
journal = {Ad Hoc Networks},
volume = {89},
pages = {47-57},
year = {2019},
issn = {1570-8705},
doi = {https://doi.org/10.1016/j.adhoc.2019.03.002},
url = {https://www.sciencedirect.com/science/article/pii/S1570870518308825},
author = {Konstantinos Skiadopoulos and Athanasios Tsipis and Konstantinos Giannakis and George Koufoudakis and Eleni Christopoulou and Konstantinos Oikonomou and George Kormentzas and Ioannis Stavrakakis},
keywords = {Data measurements synchronization, Wireless sensor networks, Internet of things, Clock deviation},
abstract = {Time synchronization is a challenging problem for wireless sensor networks, as clocks deviate and sensor measurements need to be associated with the reference clock time they took place. In Internet of Things (IoT) environments, crucial factors like energy, robustness, limited capabilities and extreme ambient conditions (e.g., when nodes are deployed in soil) lead researchers to consider various schemes of relaxing the synchronization requirements. In this paper, a lightweight synchronization algorithm is proposed for wireless sensor networks, focusing on synchronizing the particular measurements in a per hop basis as they are transmitted encapsulated in data packets towards the sink node. The aim is to synchronize data measurements instead of node clocks, and thereby, induce negligible extra overhead, since extra messages and re-synchronization periods are not required. The analysis of the proposed algorithm regarding time deviation and the corresponding variance shows a dependency on residual time (i.e., the particular time period a data packet remains within a node), distance (i.e., the number of hops between the sink node and the sensor node that sensed the data in the first place) and the average skew deviation value. Various simulations were carried out aiming to exhibit thoroughly the effectiveness of the proposed algorithm, as well as the validation of the analytical results. Findings from a comparison between the proposed algorithm and a traditional synchronization algorithm along with their simulation results show that the proposed algorithm can be a suitable solution for demanding environments like IoT systems.}}

BibTeX Entry:

@INPROCEEDINGS{tsoumanis2025energy,
author={Konidaris, Agisilaos and Tsipis, Athanasios and Sgora, Aggeliki and Koustoumpardi, Erato},
booktitle={2025 12th International Conference on Strategic Innovative Marketing and Tourism (ICSIMAT 2025)},
title={A Recommender Framework for Destination Management Organizations (DMOs) based on User-Generated Content},
year={2025},
volume={},
number={},
url={}
pages={(accepted)},
abstract={User-Generated Content (UGC), such as reviews and comments posted on platforms like Tripadvisor, Google Reviews, and Instagram, can be a valuable tool for understanding tourist experiences and preferences. In this paper, we propose a recommender framework for Destination Management Organizations (DMOs) using a Large Language Model (LLM) to analyze UGC from 51 key attractions on the Greek island of Kefalonia from Tripadvisor. The dataset included the total number of reviews with a rating of 1 to 3 posted by users up to February 2025. Our primary aim was to identify areas of dissatisfaction. The LLM analyzed each review to create tailored, actionable suggestions for DMOs, based on visitor type, time, and location. The reviews were then grouped by place and theme, filtered for relevance, and combined into a detailed yet focused strategy to support more personalized destination management. The proposed framework demonstrates the potential of integrating user feedback into destination management practices to foster more proactive and tourist-centered services.}}

BibTeX Entry:

@INPROCEEDINGS{tsoumanis2025energy,
author={Tsoumanis, Georgios and Tsipis, Athanasios and Oikonomou, Konstantinos and Kermanidou, Katia and Stavrakakis, Ioannis},
booktitle={2025 8th International Balkan Conference on Communications and Networking (BalkanCom'25)},
title={Energy Consumption Evaluation in Wireless Sensor Networks Under a Reward-based Routing Policy},
year={2025},
volume={},
number={},
url={}
pages={(to appear)},
abstract={Wireless sensor networks (WSNs) require energy-efficient routing to prolong operational lifespan. This paper proposes a reward-based routing policy that leverages local energy information to dynamically adjust paths, promoting balanced energy consumption. Implemented under a simplified, stateless Q-learning approach, the policy prioritizes immediate feedback over complex models. Simulations in OMNeT++ across varying network densities show that the proposed method outperforms Dijkstra’s algorithm in reducing peak node energy consumption, extending network lifetime, and improving fairness. Despite requiring coefficient tuning and being topology-sensitive, the policy effectively mitigates the energy hole problem and offers a lightweight alternative for energy-aware routing in WSN}}

BibTeX Entry:

@INPROCEEDINGS{giatsou2025gamification,
author={Giatsou, Georgia and Tsipis, Athanasios},
booktitle={2025 7th International Conference on Digital Culture & AudioVisual Challenges: Interdisciplinary Creativity in Arts and Technology (DCAC)},
title={Gamification and Mental Health: Prototyping an Anxiety-Supportive Gamified Mobile Application for Greek High School Students},
year={2025},
volume={},
number={},
url={}
pages={(accepted)},
abstract={}}

BibTeX Entry:

@INPROCEEDINGS{kontopanagou2025expanding,
author={Kontopanagou, Katerina and Tsipis, Athanasios and Palioura, Mirka and Komianos, Vasileios and Bacheva, Tereza},
booktitle={Art Readings 2025 International Conference, Old Art Module},
title={Expanding the Reach of Cultural Heritage, Arts, and Archives through Immersive Virtual Experiences: Showcasing the Ionian Academy and Lord Guilford Exhibition},
year={2025},
volume={},
number={},
url={}
pages={(to appear)},
abstract={}}

BibTeX Entry:

@INPROCEEDINGS{vigliraki2025navigating,
author={Vigliraki, Mary and Kontopanagou, Katerina and Tsipis, Athanasios and Tsoumanis, Georgios and Komianos, Vasileios},
booktitle={Art Readings 2025 International Conference, Old Art Module},
title={Navigating Time Capsules of Echoes: Bringing Kasos’ Maritime Legacy to Life through AI and Digital Curation},
year={2025},
volume={},
number={},
url={}
pages={(to appear)},
abstract={}}

BibTeX Entry:

@INPROCEEDINGS{vigliraki2025charting,
author={Vigliraki, Mary and Tsoumanis, Georgios and Kontopanagou, Katerina and Tsipis, Athanasios and Komianos, Vasileios},
booktitle={Art Readings 2025 International Conference, Old Art Module},
title={Charting Kasos’ Legacy: AI and the Digital Revival of Past Memories},
year={2025},
volume={},
number={},
url={}
pages={(to appear)},
abstract={}}

BibTeX Entry:

@INPROCEEDINGS{tsoumanis2024performance,
author={Komianos, Vasileios and Tsoumanis, Georgios and Tsipis, Athanasios},
booktitle={2nd International Scientific Conference on Education in Age of Artificial Intelligence},
title={Harnessing Artificial Intelligence in the Creation of Video Games for Learning Purposes},
year={2024},
volume={},
number={},
url={}
pages={(to appear)},
abstract={This paper explores the potentiality of harnessing Artificial Intelligence (AI) to create video games for learning purposes. In particular, utilizing the capabilities emerged by the evolution of Large Language Models (LLMs), the aim here is to investigate how openly available AI assistants, such as ChatGPT, can fair when requested to generate ready-to-use web source code and whether the produced educational games can effectively address the educational needs of the users and design requirements of the developers.}}

BibTeX Entry:

@INPROCEEDINGS{tsoumanis2024reward,
author={Tsoumanis, Georgios and Tsipis, Athanasios and Komianos, Vasileios and Kontopanagou, Katerina},
booktitle={2nd International Scientific Conference on Education in Age of Artificial Intelligence},
title={Reward-based Routing of Tourism Flows for Intelligent Cultural Destination Management},
year={2024},
volume={},
number={},
url={}
pages={(to appear)},
abstract={This paper presents a reward-based routing policy for managing tourism flows in cultural destinations. By using real-time data on POI (Point of Interest) occupancy and travel distances, the policy incentivizes tourists to visit less crowded sites, promoting balanced visitor distribution. Simulations demonstrate that this approach improves the completion rate of POI visits compared to a Nearest Neighbor Heuristic.}}

BibTeX Entry:

@INPROCEEDINGS{tsoumanis2024performance,
author={Tsoumanis, Georgios and Tsipis, Athanasios and Oikonomou, Konstantinos and Stavrakakis, Ioannis},
booktitle={2024 IEEE International Conference on Communication, Networks and Satellite (COMNETSAT)},
title={Performance Evaluation of a Reward-based Routing Policy for Energy Consumption Optimization in Wireless Sensor Networks},
year={2024},
volume={},
number={},
url={}
pages={(abstract)},
abstract={Wireless sensor networks play a crucial role in modern data collection systems, necessitating efficient energy consumption strategies to prolong their operational lifetime. This paper introduces and evaluates a reward-based routing policy aimed at optimizing energy consumption in wireless sensor networks. By incorporating local knowledge of the remaining energy, the proposed policy dynamically adjusts routing paths to achieve a more balanced energy consumption. The proposed policy is tested in simulations using the OMNeT++ simulator under different network densities. The results show that, compared to the Dijkstra routing algorithm, the proposed policy reduces the energy consumption of the most energy-consuming node, extends the network lifetime, and improves energy fairness by improving the Jain’s index metric. The proposed policy operates by rewarding nodes with higher remaining energy and favorable proximity to the sink, leading to a fairer energy distribution. This reward-based policy is implemented using a simplified Q-learning approach, focusing on immediate feedback rather than complex state-based models. Acknowledging potential limitations, such as the need for fine-tuning coefficients and specific topological constraints, the results highlight the significance of this approach in addressing the energy hole problem and its potential impact on future research.}}

BibTeX Entry:

@INPROCEEDINGS{komianos2024evaluating,
author={Komianos, Vasileios and Deliyannis, Ioannis and Poulimenou, Sofia Maria and Garneli, Varvara and Tsipis, Athanasios and Vogklis, Konstantinos},
booktitle={2024 International Conferences on Tourism (ICOT2024)},
title={Evaluating user experience, audience engagement and satisfaction from “Corfu Virtual Exhibition v-Corfu” and “Hologrammatic Corfu” cultural projects},
year={2024},
volume={},
number={},
url={https://iatour.org/icot2024/wp-content/uploads/2024/06/Book-of-Abstracts-ICOT2024-FINAL.pdf}
pages={(Abstract 27, pp. 64-65)},
abstract={This work presents the methodology and results of an evaluation procedure designed and implemented by researchers of Ionian University for two European co-funded cultural projects. The main goal of both projects is the creation of immersive and interactive experiences for the protection and promotion of the Cultural Heritage (CH) of the Old Town of Corfu in Greece. The "v-Corfu" project highlights important elements of Corfu, using Virtual and Augmented Reality technologies, as comparative advantages of the Ionian Islands Region in the fields of Tourism, Culture and Environment. In the framework of "Hologrammatic Corfu" a complete interactive navigation guide for the UNESCO Monument of the Old Town of Corfu was launched, intended for different users, such as visitors, locals and stakeholders of the tourist and cultural industry. The innovative characteristics of the projects, as outlined in the research and further detailed via web sources, showcase a remarkable use of technology to preserve and promote CH. They exemplify how digital technologies can be effectively harnessed to safeguard and disseminate CH, demonstrating innovative ways for cultural preservation and education. Through the use of immersive technologies, these initiatives enable a deeper connection between the public and cultural assets, ensuring that the rich history and culture of Corfu are accessible to future generations. After the projects' completion, an assessment procedure is developed to evaluate their quality assurance and help researchers understand the need for improvement and possible optimization. The work highlights the methodology, criteria, and metrics for this evaluation, and focuses on a comparative analysis of the two projects, aiming to unfold the differences between them, but mostly the commonalities. The results of this analysis will be utilized as a valuable feedback tool to establish a basis for good practices in the field and to comprehend the areas for future elaboration.}}

BibTeX Entry:

@INPROCEEDINGS{tsipis2024employing,
author={Tsipis, Athanasios and Kontopanagou, Aikaterini and Fanarioti, Sofia and Komianos, Vasileios},
booktitle={5TH CAA-GR CONFERENCE 2024 Transforming Heritage Research in a Transforming World},
title={Employing Immersive Technologies for Successful Cultural Heritage Promotion: Experience Gained from Previous Cultural Projects and the Case of the v-Corfu Project},
year={2024},
volume={},
number={},
pages={(to appear)},
abstract={Immersive technologies and their applications in Cultural Heritage are a constantly evolving area with numerous approaches, case studies and a growing number of scientific publications. The contribution of this paper is twofold; i) it gleans some of the most prominent works and combines the extracted knowledge with the practical experience from previous projects, and ii) it presents the v-Corfu project which is built upon the gained knowledge and experience. The outcome is a Virtual Reality exhibition which is the focal point of the project and which is surrounded by supplementary applications such as a digital interactive book, Augmented Reality visualizations and educational mini-games.}}

BibTeX Entry:

@INPROCEEDINGS{papamichail2023placing,
author={Papamichail, Asterios and Tsipis, Athanasios and Oikonomou, Konstantinos},
booktitle={2023 8th South-East Europe Design Automation, Computer Engineering, Computer Networks and Social Media Conference (SEEDA-CECNSM)},
title={Placing Multi-component Applications in the Multi-access Edge Computing},
year={2023},
pages={1-6},
doi={10.1109/SEEDA-CECNSM61561.2023.10470571},
abstract={Multi-access Edge Computing resolves the problem of the transportation of enormous amounts of data via the Internet by localizing the computation and the storage of data near the user. The offloading of applications to the MEC Servers must be done in a way that minimizes the latency while considering their limited resources. Additionally, there is a trend for applications to be separated into microservices that run on different MEC Servers. This adds complexity to the placement of applications on the MEC Servers because it has to take into consideration the dependencies of its microservices. This problem is defined in the literature as the multi-component application placement problem. This paper proposes an algorithm to tackle this problem efficiently, while the dependencies of services are linear, i.e., a chain of microservices. The algorithm starts with the allocation of the 1-medlan of the backhaul network. Then, the proposed algorithm extends outwards and moves around until the score function stops improving. In order to evaluate the proposed algorithm a Mixed-integer Quadratic Program is formulated. The results showed that the proposed algorithm achieved great performance in various cases}}

BibTeX Entry:

@INPROCEEDINGS{papamichail2022study,
author={Tsipis, Athanasios and Fanarioti, Sofia and Komianos, Vasileios and Sioutas, Spyros and Oikonomou, Konstantinos},
booktitle={2022 Global Information Infrastructure and Networking Symposium (GIIS)},
title={A Study on Robustness for the Single Server Location in Distributed Interactive Applications},
year={2022},
volume={},
number={},
pages={68-72},
doi={https://doi.org/10.1109/GIIS56506.2022.9936934},
abstract={In distributed interactive application ecosystems, service provision and availability are key factors for the end user's perceived quality. Therefore, the location of any server facility is important from the provider's standpoint for efficient capital expenditure. Given the dynamicity of such environments (e.g., due to traffic load variance over time), modeling this challenge as a median problem may require the continuous calculation of the optimal location. To address this robustness issue, a new robustness metric is introduced here for the case of the single server in edge computing, which depends on the overall delay experienced by the data traffic. Moreover, the smallest eigenvalue of the median matrix is considered as an alternative means for measuring this robustness. Using trace-driven simulation results, it is demonstrated that there is indeed a relationship between the proposed robustness metric and the smallest eigenvalue for the under consideration environment.}}

BibTeX Entry:

@INPROCEEDINGS{papamichail2022study,
author={Papamichail, Asterios and Tsipis, Athanasios and Tsoumanis, Georgios and Oikonomou, Konstantinos},
booktitle={2022 Global Information Infrastructure and Networking Symposium (GIIS)},
title={Study of a Proposed Spectral-based Approach for Facility Location in Tree Topologies},
year={2022},
volume={},
number={},
pages={73-77}
doi={https://doi.org/10.1109/GIIS56506.2022.9937025},
abstract={The wide proliferation of smart devices in the emerging Internet of Things (IoT) networking environment necessitates a revisit to the facility location problems, i.e., where to locate a certain service facility in order to minimize a corresponding cost function (e.g., minimize energy consumption in wireless sensor network by selecting a suitable location for the sink). To address this problem for a single facility, a spectral-based approach is presented in this paper for tree topologies considering the principal eigenvector of the distance matrix and the aggregate traffic loads. It was observed using simulation that even for those cases that the proposed approach does not produce the optimal location (i.e., the solution of the median problem), the corresponding cost is still close to the minimum.}}

BibTeX Entry:

@INPROCEEDINGS{tsipis2022fairness,
author={Tsipis, Athanasios and Komianos, Vasileios and Oikonomou, Konstantinos},
booktitle={2022 13th International Conference on Information, Intelligence, Systems and Applications (IISA)},
title={Fairness-Oriented Edge Allocation for Interactive Group Gaming in Edge Computing},
year={2022},
volume={},
number={},
pages={1-8},
doi={10.1109/IISA56318.2022.9904397},
abstract={In recent years, edge computing has emerged as a highly promising paradigm for the extension of cloud multimedia systems, enabling network latency reduction by pushing services and data from remote clouds to edge servers. For immersive distributed interactive applications, such as virtual reality and multiplayer online games, this shift has revolutionized the way nearby mobile users interact with one another to jointly participate in collaborative virtual events. However, because the virtual world is shared among many users, one fundamental decision problem for the game providers relates to: (i) how the servers will be deployed, given the limited budget in edge infrastructure investment; and, subsequently, (ii) in what manner the users will be assigned to maintain group fairness across all participating parties, given the lag variance in game view consistency. In this paper, we call this the “Fairness-oriented Edge Allocation” (FEA) problem, and formally formulate its properties and discuss its complexity. To provide solutions efficiently, we present a heuristic algorithm, namely the h-FEA, and theoretically analyze its time complexity. We, then, evaluate h-FEA against several benchmark alternatives using comprehensive simulations on a real-world topological trace. The results clearly demonstrate, under different scenarios, the superiority of our proposed algorithm in minimizing the fairness loss for users engaged with the same games, while achieving high edge user admission rates.}}

BibTeX Entry:

@INPROCEEDINGS{lampaki2022immersive,
author={Lampaki, Ioanna and Tsipis, Athanasios},
booktitle={2022 4th International Conference on Digital Culture and AudioVisual Challenges: Interdisciplinary Creativity in Arts and Technology (DCAC)},
title={Is Immersive Technology the Next Fashion Brand we want to Design in a Post-Covid e-Commerce App? Initial results from a Prototype Analysis},
year={2022},
pages={(to appear)},
abstract={The coronavirus pandemic has brought to light new opportunities regarding the dynamics of e-commerce in facilitating reliable online transactions, boosting customer loyalty and company branding, and ultimately offering an engaging and interactive means of online shopping. Although accurately capturing consumers’ satisfaction during the interaction design is still a fundamental problem, as it is affected by various parameters ranging from personal preferences and user idiosyncrasies to technical aspects and technological particularities, this shift has opened new horizons regarding the incorporation of immersive technologies and gamification approaches, in order to complement conventional and novel trends for User Interaction (UI) and User Experience (UX). In this paper, after reviewing the latest innovations in e-commerce, a prototype application of a fashion e-shop, targeted at mobile devices, is presented. The interaction design methodology utilizes a combination of emerging UI/UX methods along with immersive technologies, such as extended reality and gamification, to propose a novel virtual fashion store application. Initial results from a small-scale user evaluation verify its potential in offering exciting sensory experiences and creating the right conditions for the establishment of long-term relationships between buyers and retailers.}}

BibTeX Entry:

@INPROCEEDINGS{fanarioti2022preliminary,
author={Fanarioti, Sofia and Tsipis, Athanasios and Komianos, Vasileios},
booktitle={2022 4th International Conference on Digital Culture and AudioVisual Challenges: Interdisciplinary Creativity in Arts and Technology (DCAC)},
title={Preliminary Design of A Mixed Reality Live Storytelling Platform: Exploring the Content-Presentation and Interactivity Issues and Challenges},
year={2022},
pages={(to appear)},
abstract={This work presents a preliminary design of a Mixed Reality (MR) live storytelling platform based on literature review and user analysis to outline an initial design of modules concerning the authors’ side content presentation and manipulation mechanisms as well as the participants’ side communication and interaction mechanisms with the storytelling elements. The main objective of this paper is to understand the fundamental functional requirements of such a live storytelling platform which could then be used to fuel the ideation and implementation of the individual modules in such platforms. In this direction, an architectural schema and a use case scenario based on role-playing games are also presented to contextualize our analysis and provide insights on the key attributes, instructions and technologies required for immersive storytelling experiences.}}

BibTeX Entry:

@INPROCEEDINGS{rovithis2022ccage,
author={Rovithis, Emmanouel and Komianos, Vasileios and Vogklis, Konstantinos and Pergantis, Minas and Moustakas, Nikolaos and Kontopanagou, Katerina and Tsipis, Athanasios and Loufopoulos, Apostolos and Tsiridou, Tania and Floros, Andreas and Giannakoulopoulos, Andreas},
booktitle={2022 4th International Conference on Digital Culture and AudioVisual Challenges: Interdisciplinary Creativity in Arts and Technology (DCAC)},
title={C.CAGE (Corfu Cultural Adventure GamE): An Immersive Adventure Game to Showcase the History, Tradition, Art, and Local Creativity of Corfu},
year={2022},
pages={(to appear)},
abstract={In recent years, Augmented Reality (AR) technologies and techniques have been increasingly utilized not only to create exciting entertaining experiences but also to address the modern challenges of formal and informal education. By enriching the real environment with virtual information and facilitating user interaction with the elements of the augmented world, AR design can deliver immersive learning environments, in which users actively explore their surroundings and experientially connect with the represented content. Museums and cultural institutions all over the world are adopting AR methods to offer more autonomous and customized tours through archaeological sites, tourist destinations, and cultural exhibits. However, the cases, in which these AR cultural experiences are enhanced by game elements are scarce, and thus the educational and entertaining benefits of gamification, such as player motivation, engagement, flow and reward, are mostly neglected. This paper introduces C.CAGE, an Augmented Reality adventure game designed to promote history, tradition, art and local creativity in Corfu town, Greece. The focus of the paper lies in demonstrating the correlations established between the game's structure, content and mechanics, and the targeted cultural information. More specifically, the design process is analyzed into the following aspects: (i) structuring the game in alignment with the promotion of cultural heritage, (ii) shaping the cultural information into storytelling elements, (iii) juxtaposing interaction mechanisms onto learning mechanics, (iv) composing the game's audiovisual content, and (v) developing an in-game system for the project's dissemination to the local community and its future expansion. Furthermore, technical and functional characteristics are briefly discussed, dealing with conceptual and practical design challenges that will contribute to providing a framework for the development of AR games in the wider context of cultural heritage.}}

BibTeX Entry:

@INPROCEEDINGS{9593261,
author={Tsipis, Athanasios and Komianos, Vasileios},
booktitle={2021 4th International Balkan Conference on Communications and Networking (BalkanCom)},
title={Scalable Server Location for Distributed Interactive Applications Under Budget Constraints},
year={2021},
volume={},
number={},
pages={21-25},
doi={https://doi.org/10.1109/BalkanCom53780.2021.9593261},
abstract={Mobile Edge Computing (MEC) has emerged as a popular paradigm for the support of distributed interactive applications (DIAs), promising continuous service provision and availability to mobile users, that is otherwise not easily attainable under the centralized cloud-only model. Yet, in order to alleviate the app provider from unnecessary capital expenditure, a judicious location of the edge servers must be adopted, that can effectively cope with both the network demands and the deployment cost, and still abide by the budget constraints of the app provider. In this paper, we formally formulate the problem as a budget-constrained facility location problem. We then propose a distributed and scalable algorithm, that employs elastic server relocation, to address it. Trace-driven simulations under various MEC deployment scenarios verify the expected behavior and testify to the algorithm’s accountability in obeying the budget limits and converging to a placement solution close to the optimal in finite time slots, rendering it suitable for DIAs ecosystems.}}

BibTeX Entry:

@INPROCEEDINGS{9593230,
author={Komianos, Vasileios and Tsipis, Athanasios and Kontopanagou, Katerina},
booktitle={2021 4th International Balkan Conference on Communications and Networking (BalkanCom)},
title={Design of a Computational Offloading Platform for Immersive Experiences in Digital Culture},
year={2021},
volume={},
number={},
pages={40-44},
doi={https://doi.org/10.1109/BalkanCom53780.2021.9593230},
abstract={Recent advances in three-dimensional (3D) media delivery technologies, such as Augmented and Mixed Reality, have paved the way towards the realization of high-quality immersive experiences in digital culture applications. Nowadays, these services play a crucial role in cultural heritage dissemination, transforming visitors from passive spectators into proactive culture caretakers and content creators. Nevertheless, they demand significant computational resources and are subject to low delay tolerances, that are generally difficult to acquire via standard mobile devices. Under this scope, the current paper deals with the preliminary design of a hybrid cloud/edge computing platform for the support of digital culture applications. The goal is to recognize computationally intensive services that are to be offloaded based on their resource and time criticality to the cloud or edge respectively, and offer constant guarantees regarding the visitors’ Quality of Experience. The use case of Byzantine Monuments and Churches is also reported to better contextualize the approach and present the platform’s layering and data flow.}}

BibTeX Entry:

@INPROCEEDINGS{9593243,
author={Skiadopoulos, Konstantinos and Tsipis, Athanasios and Oikonomou, Konstantinos},
booktitle={2021 4th International Balkan Conference on Communications and Networking (BalkanCom)},
title={Constructing Budget Connected Dominating Sets in Large-Scale IoT Network Environments},
year={2021},
volume={},
number={},
pages={75-79},
doi={https://doi.org/10.1109/BalkanCom53780.2021.9593243},
abstract={Several critical operations depend on various types of information dissemination in the Internet of Things (IoT) networks. To avoid costly flooding-based solutions in these typically large-scale network environments, it is frequently sufficient enough to involve only a proper subset of the nodes (or backbone network), ensuring that every other node will be at most d hops away from a node belonging to the specific subset, i.e., a connected dominating set (CDS). In many cases, the outputted CDS size is upper bounded by a specific physical requirement or constraints relating to the limited available processing and memory capacities of the IoT nodes. Thus, a budget parameter k is frequently introduced as an upper bound for the number of nodes comprising the CDS, leading to the creation of a Budget Connected Dominating Set (BCDS). In this work, a novel distributed algorithm for constructing a BCDS is proposed based on information available d hops away from the network nodes, assuming an upper budget k limit regarding its final size. An additional upper bound parameter relating to the number of sent messages for each node, i.e., the stop, is also for the first time utilized. It is shown using simulation results that when stop is employed, a BCDS with increased coverage (i.e., the fraction of nodes at most d hops away from the BCDS nodes) is constructed under the proposed algorithm.}}

BibTeX Entry:

@INPROCEEDINGS{9631480,
author={Tsipis, Athanasios and Oikonomou, Konstantinos},
booktitle={2021 IEEE Symposium on Computers and Communications (ISCC)},
title={Player Assignment in MEC Gaming for Social Interactivity and Server Provisioning Optimization},
year={2021},
volume={},
number={},
pages={1-7},
doi={https://doi.org/10.1109/ISCC53001.2021.9631480},
abstract={In Mobile Edge Computing (MEC), edge servers are deployed on Base Stations (BSs) to provide high accessibility to nearby users, alleviating the computational burden of the remote cloud and significantly reducing network delays. Still, for distributed interactive applications (DIAs), such as cloud games, where players team up and form social communities, one fundamental challenge is the discovery of the most suitable player-to-server assignment, that achieves a balanced tradeoff between low-delay social interactivity and low-cost server provisioning, under strict proximity and capacity constraints. In this paper, we formally model the problem via mixed-integer linear programming. However, its solution is complex falling under the category of existing capacitated facility location problems. Thus, we present the “Interactivity-based Edge Server Allocation” (IESA) algorithm, a novel heuristic approach to efficiently assign and then iteratively improve the player-to-server allocation. IESA is evaluated using trace-driven simulations that demonstrate how it outperforms the baseline and state-of-the-art assignment alternatives.}}

BibTeX Entry:

@inproceedings{tsipis2021distributed,
author= {Tsipis, Athanasios and Komianos, Vasileios and Oikonomou, Konstantinos},
title= {Distributed Computing Paradigms for Optimization of Mixed Reality Applications in Digital Culture},
booktitle= {Proceedings of the 2021 3rd International Conference on Digital Culture and AudioVisual Challenges: Interdisciplinary Creativity in Arts and Technology (DCAC)},
year= {2021},
pages= {(to appear)},
abstract= {Given the wide proliferation of immersive applications nowadays, such as Mixed Reality (MR), broad research is continuously being conducted on their applicability and impact on Digital Culture. Still, most of these applications are time-constrained, requiring heavy computation in order to keep track of the engaged users’ navigation and orientation, and in parallel generate high-quality three-dimensional (3D) graphics that are perfectly mapped to their surroundings, a fact that is not easily attainable through standard mobile devices. These issues are exceedingly difficult to address when considering large-scale Cultural Heritage environments, where numerous users are present at any given moment, resulting in fluctuating network conditions and service demands. Motivated by the capabilities offered by the emerging Mobile Edge Computing paradigm, this paper shares insights regarding potential optimization approaches that can be adopted in order to speed up the complex user tracking, area mapping, and 3D rendering processes in Digital Culture. The main goal is to deliver scalable MR applications with constant Quality of Experience guarantees to the visitors, by exploiting existing and elastic infrastructure in close proximity to cultural landmarks within large-scale Cultural Heritage sites.}}

BibTeX Entry:

@INPROCEEDINGS{9221778,
author={Tsipis, Athanasios and Oikonomou, Konstantinos and Komianos, Vasileios and Stavrakakis, Ioannis},
booktitle={2020 5th South-East Europe Design Automation, Computer Engineering, Computer Networks and Social Media Conference (SEEDA-CECNSM)},
title={QoE-Aware Rendering Service Allocation in Fog-Assisted Cloud Gaming Environments},
year={2020},
volume={},
number={},
pages={1-8},
doi={https://doi.org/10.1109/SEEDA-CECNSM49515.2020.9221778},
abstract={Cloudification of heterogeneous networks along with the virtualization of gaming resources, allow the game providers to move into the cloud gaming era. Cloud gaming offloads computation-intensive tasks to the cloud in order to alleviate the computational burden of end-users' devices, but introduces delay which deteriorates their Quality of Experience (QoE). To solve the optimization problem of rendering service allocation with QoE guarantees and reduce the operational expenditures of game providers, fog computing is deemed a promising solution. However, the optimization problem is NP-hard since it falls into the category of the well-known Facility Location Problems. In the current paper, a distributed policy is proposed, named QoE-Aware Rendering Service Allocation (QoERSA), which takes advantage of strictly local network information, to reallocate the rendering services inside the fog computing network, towards an optimal delay-sensitive placement, given the QoE gaming constraints and the need for capital investment reduction. To this end, it employs Mean Opinion Score objective QoE assessment and simple mechanics that move, copy and merge services with high elasticity and scalability. QoERSA is evaluated through simulations that highlight its efficiency and showcase its capability of overall service access and deployment cost reduction.}}

BibTeX Entry:

@INPROCEEDINGS{9284390,
author={Tsipis, Athanasios and Komianos, Vasileios and Oikonomou, Konstantinos and Stavrakakis, Ioannis},
booktitle={2020 11th International Conference on Information, Intelligence, Systems and Applications (IISA)},
title={Elastic Distributed Rendering Service Placement in Capacitated Cloud/Fog Gaming Systems},
year={2020},
volume={},
number={},
pages={1-8},
doi={https://doi.org/10.1109/IISA50023.2020.9284390},
abstract={Fog-assisted cloud computing advances have paved the way for new solutions in online gaming, by integrating all rendering resources directly into the edges of the cloud. However, despite the numerous benefits, these systems still remain prone to network delays, ergo, the discovery of an optimal rendering service placement in the fog layer, that effectively reduces capital deployment cost for the game providers and access latency cost for the game clients, is a challenging issue. In fact, it falls into the category of the well-known (NP-hard) facility location problems. As such, conventional centralized approaches, that require global network knowledge, in most cases are deemed unscalable and cost-prohibitive, thus, distributed solutions must be further explored. The approach followed here, introduces a Rendering Service Allocation Policy (RSAP) to autonomously allocate services towards an optimal placement, based strictly on local information available to the fog renderers regarding their aggregate rendering demands, yielding reduced access latency and deployment costs, whilst meeting their stringent capacity bounds. Simulation results showcase the efficiency of RSAP and verify its elastic behavior under different deployment scenarios.}}

BibTeX Entry:

@INPROCEEDINGS{8908282,
author={Tsipis, Athanasios and Komianos, Vasileios and Oikonomou, Konstantinos},
booktitle={2019 4th South-East Europe Design Automation, Computer Engineering, Computer Networks and Social Media Conference (SEEDA-CECNSM)},
title={A Cloud Gaming Architecture Leveraging Fog for Dynamic Load Balancing in Cluster-Based MMOs},
year={2019},
volume={},
number={},
pages={1-6},
doi={https://doi.org/10.1109/SEEDA-CECNSM.2019.8908282},
abstract={Massively Multiplayer Online (MMO) games have been around for quite some time now, attracting millions of users worldwide, making them one of the most successful video game genres. Many load balancing approaches have been proposed over the years in order to optimize Quality of Experience (QoE) and achieve better scalability and user coverage. These usually split the game world into different clusters using a multi-server architecture. However, not many exist that take into consideration conditions that arise from the newly emerged Internet of Everything (IoE) and cloud/fog gaming paradigms. Hence, the aim here is to present a novel cloud gaming architecture that leverages the capabilities of fog computing for achieving a two level dynamic load balancing in cluster-based multi-server MMOs through the use of an appropriate algorithm. The proposed architecture and algorithm are also validated via preliminary simulation experiments, indicating a high user coverage ratio and a balanced distribution of the load in terms of client proportionality in the servers, even under forced strict gaming conditions.}}

BibTeX Entry:

@inproceedings{tsipis2019performance,
author = {Tsipis, Athanasios and Oikonomou, Konstantinos and Komianos, Vasileios},
title = {Performance evaluation in cloud-edge hybrid gaming systems},
year = {2019},
pages = {1--5},
abstract={Cloud gaming architectures have emerged in efforts to provide efficient execution of computer video games in computer machines and mobile devices with low processing/rendering capabilities. Such approaches are prone to network delays since the rendering process is offloaded to the cloud, hence, increasing cloud's computational needs and decreasing user coverage. To tackle this challenge cloud-edge hybrid gaming systems were proposed in order to reduce network latency and improve user experience. By deploying rendering devices at the edge of the cloud and in close proximity to the end users, cloud-edge hybrid systems aim at augmenting the cloud's computational capacity and reducing the game's response time. In current work a preliminary simulation model to evaluate the performance of such systems and test the above hypothesis is presented, showing that cloud-edge hybrid gaming systems are able to outperform conventional cloud gaming architectures in latency reduction.}}

BibTeX Entry:

@inproceedings{fanarioti2018proposed,
author = {Fanarioti, Sofia and Tsipis, Athanasios and Giannakis, Konstantinos and Koufoudakis, George and Christopoulou, Eleni and Oikonomou, Konstantinos and Stavrakakis, Ioannis },
title = {A proposed algorithm for data measurements synchronization in wireless sensor networks},
year = {2018},
pages = {1--5},
abstract={The proliferation of wireless sensor networks supports nowadays numerous areas of everyday life and activities. Each sensor node senses some data of interest (e.g., humidity, temperature) and the corresponding measurements need to be tagged with the reference time (usually sink node’s time) they took place, in order to be further analyzed. Given that clocks deviate, time synchronization is a challenging problem in this network environment. In this paper, the focus is on synchronizing the particular measurements in a per hop basis as they are transmitted encapsulated in data packets towards the sink node, instead of synchronizing the node clocks, thus, inducing no extra overhead. In this direction, a synchronization algorithm is proposed here based on MAC layer time stamping. Analytical results regarding the average time deviation and the corresponding variance under the proposed algorithm show a dependency on the residual time (i.e., the time period a data packet remains with a node), the distance (i.e., the number of hops between the sink node and the sensor node that sensed the data initially) and the average skew deviation value. The effectiveness of the algorithm as well as the validation of the analytical results are demonstrated thoroughly using simulation results.}}

BibTeX Entry:

@INPROCEEDINGS{angelis2023tcp,
author={Angelis, Ioannis and Tsipis, Athanasios and Christopoulou, Eleni and Oikonomou, Konstantinos},
editor={Gao, Honghao and Wang, Xinheng and Voros, Nikolaos},
title={TCP Cubic Implementation in the OMNeT++ INET Framework for SIoT Simulation Scenarios},
booktitle={Collaborative Computing: Networking, Applications and Worksharing},
year={2024},
publisher={Springer Nature Switzerland},
address={Cham},
volueme={561},
pages={18--37},
abstract={TCP is a well-known protocol for reliable data transfer. Although TCP was originally designed for networks with low Round Trip Time (RTT) and low error rates over the communication channel, in modern networks these characteristics vary drastically, e.g., Long Fat Networks are usually attributed a high Bandwidth Delay Product. When considering satellite communications, which are also characterized by high error rates but are considered a driving force for future networks, such as the Satellite Internet of Things (SIoT), it becomes clear that there exists an ever-growing need to revisit TCP protocol variants and develop new tools to simulate their behavior and optimize their performance. In this paper, a TCP Cubic implementation for the OMNeT++ INET Framework is presented and made publicly available to the research community. Simulation experiments validate its expected behavior in accordance with the theoretical analysis. A performance comparison against the popular TCP NewReno is also performed to evaluate TCP Cubic's applicability to satellite environments. The obtained results testify to the latter's superiority in efficiently allocating the bandwidth among the different information flows with vast gains to the overall system throughput, thus, rendering it the better candidate for future SIoT environments.},
isbn={978-3-031-54521-4}}

BibTeX Entry:

@Inbook{angelis2022smart,
author="Angelis, Ioannis and Zervopoulos, Alexandros and Alvanou, Aikaterini Georgia and Vergis, Spiridon and Papamichail, Asterios and Bezas, Konstantinos and Stylidou, Andreana and Tsipis, Athanasios and Komianos, Vasileios and Tsoumanis, Georgios and Koufoudakis, George and Oikonomou, Konstantinos",
editor="Bochtis, Dionysis D. and Lampridi, Maria and Petropoulos, George P. and Ampatzidis, Yiannis and Pardalos, Panos",
title="Smart Agriculture: A Low-Cost Wireless Sensor Network Approach",
bookTitle="Information and Communication Technologies for Agriculture---Theme I: Sensors",
year="2022",
publisher="Springer International Publishing",
address="Cham",
pages="139--172",
abstract="Due to the rapid urbanization in many developing countries along with other major factors, such as global warming, the agriculture industries are striving to cope nowadays more than ever. This chapter gives a better insight on how the Information Communications Technologies and the development of Internet of Things applications can be used in the field of agriculture. While presenting general information regarding issues faced by these industries, the chapter focuses on analyzing the various low-cost hardware components (sensors, processing units, etc.), a simple Wireless Sensor Network synchronization method and a cloud/fog architecture suitable for environmental monitoring and agricultural applications. The effectiveness of the synchronization process is evaluated with experiments previously conducted on an olive grove. Likewise, the cloud/fog architecture is evaluated based on previous experimental runs led by other researchers. The results of both approaches are briefly presented and analyzed. The performance evaluation metrics used to outline their effectiveness are the Round Trip Time of a data packet and the packet load on every time step. A brief review of the key components of each of the aforementioned subjects is presented and possible future directions are provided.",
isbn="978-3-030-84144-7",
doi="https://doi.org/10.1007/978-3-030-84144-7_6",
url="https://doi.org/10.1007/978-3-030-84144-7_6"}

BibTeX Entry:

@inproceedings{katsalirou2024digiflora,
author = {Κατσαλήρου, Ειρήνη and Γεράκης, Αργύριος and Ανανιάδης Μπασιάς, Αλέξανδρος and Ματιάτου, Ευαγγελία and Κονιδάρης, Αγησίλαος and Πετράκης, Κώστας Αντ. and Ιωαννίδης, Βασίλης and Σπαρασέλλο, Νικόλαος and Σκιαδαρέσης, Αριστοτέλης and Χριστοφοράτου, Ελένη and Δουλκερίδου, Δέσποινα and Βασάλα, Παρασκευή and Τσίπης, Αθανάσιος},
title = {DIGIflora: Ανάπτυξη Ψηφιακών Εφαρµογών για την Ανάδειξη της Χλωρίδας των Ιονίων Νήσων},
booktitle = {Proceedings of the 18th Panhellenic Scientific Conference of the Hellenic Botanical Society (HBS 2024)},
year = {2024},
pages = {(Abstract B' 15, p. 147)(poster)},
abstract = {In our modern digital world, we recognize the need to document plant communities and selected plants on the world wide web. DIGIflora is an innovative project that combines two cutting-edge technologies, Virtual Reality (VR) and Augmented Reality (AR), in one bilingual web application that enables users to explore the Ionian Islands and their rich biodiversity, both before their visit and during their stay. The Ionian Islands host over 2,500 species and subspecies of native flora, many of which have significant ethnobotanical value. Knowledge of the gastronomic, medicinal, and cultural uses of these plants is at risk of being lost due to significant changes affecting the natural environment and lifestyle. The primary aim of the project is to showcase the rich native flora of the Ionian region and preserve its ethnobotanical tradition, while also diversifying and enhancing the value of its tourism product. With DIGIflora, users can virtually experience the high aesthetic and ecological value of habitats of exceptional natural beauty. They can also learn interactively about the rich ethnobotanical tradition, as well as the medicinal, gastronomic, ritualistic, and cultural uses of native species. As part of the project, an online educational application was created specifically for students. It features selected flora species from Cephalonia Botanica, highlighting their ethnobotanical value through interactive games. This allows students to explore the botanical garden and familiarize themselves with its rich plant collection. The project was implemented by the Ionian University in collaboration with Cephalonia Botanica and involved the participation of over 30 collaborators. The DIGIflora applications are accessible for free at digiflora.fst.ionio.gr.}}

BibTeX Entry:

@inproceedings{tsipis2024alternative,
author = {Τσίπης, Αθανάσιος and Φαναριώτη, Σοφία and Κοντοπανάγου, Αικατερίνη Κ. and Κομιανός, Βασίλειος},
title = {Εναλλακτικές Πραγματικότητες και Ψηφιακές Εφαρμογές για την Ανάδειξη Αρχιτεκτονικής Κληρονομιάς: Η Περίπτωση της Κέρκυρας και του Έργου v-Corfu},
booktitle = {Proceedings of the 5th Pan-Hellenic Conference on Digital Cultural Heritage (EuroMed 2023)},
year = {2024},
pages = {689-698},
abstract = {Οι εμβυθιστικές τεχνολογίες έχουν αναδυθεί ως καινοτόμες προτάσεις για την ανάδειξη του υλικού ή μη υφιστάμενου πολιτισμικού κεφαλαίου ενός τόπου. Παράλληλα, παρατηρείται ότι νέες και πρωτότυπες μέθοδοι παρουσίασης της αρχιτεκτονικής κληρονομιάς προσελκύουν σταθερά το κοινό, νέο ή παλιό. Υπό το πρίσμα αυτό, η αναπαράσταση πολιτιστικών αντικειμένων και κτηρίων μέσω ψηφιακών τριδιάστατων (3Δ) μοντέλων, πλαισιωμένα από καθηλωτικές εμπειρίες και διαδραστικά εικονικά περιβάλλοντα, επιτρέπει τη δημιουργία νέων μονοπατιών γνώσης, τροφοδοτώντας την εμπεριστατωμένη κατανόηση και ενεργό συμμετοχή του χρήστη στη διαδικασία προώθησης και ανάδειξής τους. Στην παρούσα εργασία μελετάται η χρήση εναλλακτικών πραγματικοτήτων (εικονική, επαυξημένη, εκτεταμένη, κτλ.) για την ενημέρωση του κοινού σχετικά με την αρχιτεκτονική κληρονομιά, λαμβάνοντας υπόψη την περίπτωση της Κέρκυρας και το έργο με τίτλο «Εικονικός Εκθεσιακός Χώρος Κέρκυρας στους Τομείς Πολιτισμού, Τουρισμού και Περιβάλλοντος» (v-Corfu). Το έργο ακολουθεί μία πολύπλευρη προσέγγιση για την αλληλεπίδραση με το ψηφιακό περιεχόμενο που επιτρέπει στους εικονικούς επισκέπτες να περιηγηθούν και να έρθουν σε επαφή με τα εικονικά εκθέματα όπως θα έκαναν σε έναν πραγματικό εκθεσιακό χώρο ή μουσείο. Συνδυάζοντας διαφορετικές εμβυθιστικές τεχνολογίες, το v-Corfu τοποθετεί τα 3Δ αρχιτεκτονικά μνημεία στο επίκεντρο της εικονικής έκθεσης, καθιστώντας το ευρύ κοινό κοινωνό της γνώσης αυτής. Συμπληρωματικές εφαρμογές, όπως ψηφιακά μίνι παιχνίδια, και πλούσιο πληροφοριακό και πολυμεσικό περιεχόμενο επεκτείνουν την εμπειρία προσφέροντας ευκαιρίες για ψυχαγωγία και μάθηση.}}

BibTeX Entry:

@inproceedings{vainopoulos2024digital,
author = {Βαϊνόπουλος, Αποστόλης and Τσίπης, Αθανάσιος and Καρύδης, Χρήστος and Κομιανός, Βασίλειος},
title = {Ψηφιακή 3Δ αποκατάσταση και εφαρμογές ανάδειξης της παλαιοχριστιανικής βασιλικής εκκλησίας στο Εμπορειό της Χίου},
booktitle = {Proceedings of the 5th Pan-Hellenic Conference on Digital Cultural Heritage (EuroMed 2023)},
year = {2024},
pages = {663-673},
abstract = {Η εργασία παρουσιάζει τη δημιουργία και την αναπαράσταση της παλαιοχριστιανικής βασιλικής εκκλησίας του Εμπορειού της Χίου σε τριδιάστατη (3Δ) μορφή. Η εκκλησία του Εμπορειού της Χίου αποτελεί ένα μνημείο μεγάλης σημασίας για την τοπική ιστορία.. Τα εναπομείναντα κομμάτια της, ο αρχιτεκτονικός της διάκοσμος και οι ιστορικές καταγραφές της προσφέρουν λίγες πληροφορίες σχετικά με την αρχιτεκτονική της λόγω των καταστροφών που έχουν επέλθει με το πέρασμα του χρόνου.  Αντικείμενο της παρούσας μελέτης είναι η παρουσίαση της διαδικασίας επεξεργασίας των διαθέσιμων στοιχείων σε συνεργασία με την τοπική εφορεία αρχαιοτήτων για την εικονική αποκατάσταση της, η παρουσίαση της διαδικασίας δημιουργίας διαφορετικών εκδόσεων του τριδιάστατου μοντέλου βάσει των διαθέσιμων πληροφοριών και η αξιολόγησης τους. Επίσης, παρουσιάζεται η διαδικασία δημιουργίας της εφαρμογής περιήγησης με χρήση λογισμικού ανάπτυξης ψηφιακών παιχνιδιών, καθώς και συμπληρωματικού προωθητικού υλικού, όπως αρχεία 3Δ κατάλληλα για διαμοιρασμό και επαναχρησιμοποίηση και περιηγήσεις σε μορφή βίντεο. Η παρούσα εργασία δίνει επίσης έμφαση στο μοντέλο εργασίας, τις συνεργατικές διαδικασίες και τα εργαλεία που χρησιμοποιήθηκαν για την υλοποίηση του έργου με στόχευση σε μικρές ομάδες εργασίας και έργα χαμηλού προϋπολογισμού.}}

BibTeX Entry:

@inproceedings{tsipis2015building,
author = {Tsipis, Athanasios and Tsompolis, Alexandros and Fanarioti, Sofia and Oikonomou, Konstantinos},
title = {Building a Low-Cost Virtual Reality Museum Application (VR-Mapp)},
booktitle = {Proceedings of the 2nd Student Conference on Modern Entrepreneurship and Information Technology (FSTEP 2015)},
year = {2015},
pages = {1-11},
abstract={Current work discusses the role of virtual worlds in museums for purposes of promoting cultural heritage and enhancing their educational value. In this context, a VR application regarding the case study of the Folklore Museum of Paxos is being presented here. The proposed VR museum application (VR-Mapp) is affordable in the sense of both implementation and distribution to the users. It is easily programmable and configurable even by students, amplifying their role in the society’s economy, innovation and entrepreneurship. Additionally, it takes advantage of accessible technological means in order to equip the user with the ability to visit the museum without the need of physical presence. The main aim is to provide an alternative virtual tour solution by exploiting low-budget devices, specifically, smartphones and the Google Cardboard. VR-Mapp places the user in the art gallery of the Museum of Paxos where he/she can virtually navigate through carefully placed virtual points (v-points) inside the room. Furthermore, a v-point could be assigned on an important artifact, in order to retrieve information and explore the scene in a 360° viewing angle. VR-Mapp enables the user to engage on a highly interactive virtual museum. It is believed that the people who will most benefit from VR-Mapp are vulnerable groups, including students and the physically disabled. VR-Mapp provides the museums with the ability to highlight their digital historical content and preserve their cultural heritage in an easy, affordable, intuitive and thrilling manner.}}

BibTeX Entry:

@theses{theses:PhD,
author = {Tsipis, Athanasios},
title = {Network resource optimization in cloud computing environments},
address = {Ionian University, Corfu, Greece},
booktitle = {PhD Dissertation},
publisher = {Dept. of Informatics},
month = {January},
year = {2021},
doi = {http://dx.doi.org/10.12681/eadd/48819}}

BibTeX Entry:

@theses{theses:M.Sc.,
author = {Tsipis, Athanasios},
title = {Representation of the Old Municipal Theatre of Corfu in a Virtual World},
address = {Ionian University, Corfu, Greece},
booktitle = {M.Sc. Thesis},
publisher = {Dept. of Informatics},
month = {February},
year = {2017}}

BibTeX Entry:

@theses{theses:B.Sc.,
author = {Tsipis, Athanasios},
title = {Reviving the Historical Past in the Virtual Present: Virtual Reconstruction of the Villa Rosa},
address = {Ionian University, Corfu, Greece},
booktitle = {B.Sc. Thesis},
publisher = {Dept. of Informatics},
month = {February},
year = {2015}}