Publications

Scientific papers and publications by our lab members.

A Survey on the Computing Continuum and Meta-Operating Systems: Perspectives, Architectures, Outcomes, and Open Challenges

Authors: P. Gkonis, A. Giannopoulos, N. Nomikos, L. Sarakis, V. Nikolakakis, G-D. Patsourakis, P. Trakadas

Journal: Sensors

Details: Vol. 26, No. 3, pp. 799

Publisher: MDPI

Year: 2026

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A Distributed Trustable Framework for AI-Aided Anomaly Detection

Authors: N. Nomikos, G. Xylouris, G. Patsourakis, V. Nikolakakis, A. Giannopoulos, C. Mandilaris, P. Gkonis, C. Skianis, P. Trakadas

Journal: Electronics

Details: Vol. 14, No. 3, pp. 410

Publisher: MDPI

Year: 2025

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A FinTech-Aligned Optimization Framework for IoT-Enabled Smart Agriculture to Mitigate Greenhouse Gas Emissions

Authors: S. Polymeni, D. N. Skoutas, G. Kormentzas, C. Skianis

Journal: Information

Details: Vol. 16, No. 9, pp. 797

Publisher: MDPI

Year: 2025

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A Survey on Architectural Approaches for 6G Networks: Implementation Challenges, Current Trends, and Future Directions

Authors: P. Gkonis, A. Giannopoulos, N. Nomikos, P. Trakadas, L. Sarakis, X. Masip

Journal: Telecom

Details: Vol. 6, No. 2, pp. 27

Publisher: MDPI

Year: 2025

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A Survey on UxV Swarms and the Role of Artificial Intelligence as a Technological Enabler

Authors: A. Dimos, D. N. Skoutas, N. Nomikos, C. Skianis

Journal: Drones

Details: Vol. 9, No. 10, pp. 700

Publisher: MDPI

Year: 2025

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Active, Passive, and Absorptive RIS-Aided 6G Network Under Non-Orthogonal CCI

Authors: V. Ozduran, E. Nasab, N. Nomikos, I. Ansari, P. Trakadas

Journal: Open Journal of Vehicular Technology

Details: Vol. 6, pp. 2644-1330

Publisher: IEEE

Year: 2025

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FLUID: Dynamic Model-Agnostic Federated Learning with Pruning and Knowledge Distillation for Maritime Predictive Maintenance

Authors: A. Kalafatelis, A. Pitsiakou, N. Nomikos, N. Tsoulakos, T. Syriopoulos, P. Trakadas

Journal: Journal of Marine Science and Engineering

Details: Vol. 13, No. 6, pp. 1569

Publisher: MDPI

Year: 2025

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From 6G to SeaX-G: Integrated 6G TN/NTN for AI-Assisted Maritime Communications - Architecture, Enablers, and Optimization Problems

Authors: A. Giannopoulos, P. Gkonis, A. Kalafatelis, N. Nomikos, S. Spantideas, P. Trakadas, T. Syriopoulos

Journal: Journal of Marine Science and Engineering

Details: Vol. 13, No. 6, pp. 1103

Publisher: MDPI

Year: 2025

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M‐SADR: Mobile Self Adaptive Data Rate for Enhanced LoRa End‐Device Connectivity on the Move

Authors: V. Moysiadis, P. Radoglou‐Grammatikis, E. Mourikis, M. Zevgara, D. N. Skoutas, C. Skianis, P. Sarigiannidis

Journal: International Journal of Communication Systems

Details: Vol. 38, No. 15

Publisher: Wiley

Year: 2025

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Towards predictive maintenance in the maritime industry: A component-based overview

Authors: A. Kalafatelis, N. Nomikos, A. Giannopoulos, G. Alexandridis, A. Karditsa, P. Trakadas

Journal: Journal of Marine Science and Engineering

Details: Vol. 13, No. 3, pp. 425

Publisher: MDPI

Year: 2025

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"A Versatile, Low-Cost Monitoring Device suitable for Non-Intrusive Load Monitoring Research Purposes"

Authors: S. Kotsilitis, E. C. Marcoulaki, E. Kalligeros

Journal: Measurement: Sensors

Details: Vol. 32, pp. 101081

Publisher: Elsevier

Year: 2024

Abstract
Energy systems monitoring is a key factor in reducing global energy consumption. Although intrusive approaches can be adopted, Non-Intrusive Load Monitoring (NILM), which targets estimation of individual-appliance consumption from aggregated electricity measurements, is the main choice for retrofitting the plethora of non-smart electrical installations. Contemporary NILM requirements include high-frequency power-line sampling, efficient disaggregation algorithms that can, potentially, run locally, on the monitoring device, to offload the remote fog/cloud infrastructure, and various open datasets to allow the development of such algorithms. Towards all these directions, in this paper, a versatile monitoring device to support NILM research is presented. It offers high sampling frequency, sufficiency of local resources, and has been designed to be used in different environments (residential, commercial, industrial). Actually, it was deployed in all these environments, with multiple copies of it being used in two different industrial facilities for over two years. The developed device’s cost has been kept low, its accuracy has been experimentally verified to be sufficiently high, while its key hardware characteristics, in the context of NILM research, compare favorably with those of other devices in the literature. Along with the device, a residential, high-frequency dataset is also presented and made publicly available.
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A stochastic geometry-based performance analysis of a UAV corridor-assisted IoT network

Authors: H. K. Armeniakos, K. Maliatsos, P. Bithas, A. G. Kanatas

Journal: Frontiers in Communications and Networks

Publisher: Frontiers

Year: 2024

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Achievable Secrecy Rate Analysis of OFDM-Based Multi-User Untrusted Relay Networks with Imperfect CSI

Authors: V. Ozduran, N. Nomikos, I. Ansari

Journal: Transactions on Emerging Telecommunications Technologies

Details: Vol. 35, No. 6

Publisher: Wiley

Year: 2024

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Bandit-Based Learning-Aided Full-Duplex/Half-Duplex Mode Selection in 6G Cooperative Relay Networks

Authors: N. Nomikos, T. Charalambous, P. Trakadas, R. Wichman

Journal: Open Journal of the Communications Society

Details: Vol. 5, pp. 1415-1429

Publisher: IEEE

Year: 2024

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Combining serious games and machine learning to assess the cognitive state of seniors using the cogniplat platform

Authors: G. Skikos, C. Goumopoulos, J. Ferras

Journal: Journal of Ambient Intelligence and Humanized Computing

Year: 2024

Combining Serious Games and Machine Learning to Assess the Cognitive State of Seniors Using the Cogniplat Platform

Authors: G. Skikos, C. Goumopoulos

Journal: Journal of Ambient Intelligence and Humanized Computing

Publisher: Springer

Year: 2024

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Federated Learning for Maritime Environments: Use Cases, Experimental Results, and Open Issues

Authors: A. Giannopoulos, P. Gkonis, P. Bithas, N. Nomikos, A. Kalafatelis, P. Trakadas

Journal: Journal of Marine Science and Engineering

Details: Vol. 12, No. 6

Publisher: MDPI

Year: 2024

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Federated Learning-Aided Prognostics in the Shipping 4.0: Principles, Workflow, and Use Cases

Authors: A. Angelopoulos, A. Giannopoulos, N. Nomikos, A. Kalafatelis, A. Hatziefremidis, P. Trakadas

Journal: Access

Details: Vol. 12, pp. 6437-6454

Publisher: IEEE

Year: 2024

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FedShip: Federated Over-the-Air Learning for Communication-Efficient and Privacy-Aware Smart Shipping in 6G Communications

Authors: A. Giannopoulos, S. Spantideas, M. Zetas, N. Nomikos, P. Trakadas

Journal: Transactions on Intelligent Transportation Systems

Publisher: IEEE

Year: 2024

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Improving Connectivity in 6G Maritime Communication Networks with UAV Swarms

Authors: N. Nomikos, A. Giannopoulos, A. Kalafatelis, V. Ozduran, P. Trakadas, G. K. Karagiannidis

Journal: Access

Details: Vol. 12, pp. 18739-18751,

Publisher: IEEE

Year: 2024

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Joint Energy and SINR Coverage Probability in UAV Corridor-assisted RF-powered IoT Networks

Authors: H. K. Armeniakos, P. Bithas, K. Maliatsos, A. G. Kanatas

Journal: IEEE Communications Letters

Publisher: IEEE

Year: 2024

Joint Sensing and Communications in Unmanned-Aerial-Vehicle-Assisted Systems

Authors: P. Bithas, G. Efthymoglou, A. G. Kanatas, K. Maliatsos

Journal: Drones 2024

Details: Vol. 8, No. 11

Publisher: mdpi

Year: 2024

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Leveraging Network Data Analytics Function and Machine Learning for Data Collection, Resource Optimization

Authors: P. Gkonis, N. Nomikos, P. Trakadas, L. Sarakis, G. Xylouris, X. Masip, J. Martrat

Journal: Access

Details: Vol. 12, pp. 21320-21336

Publisher: IEEE

Year: 2024

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Non-Terrestrial Networks for Energy-Efficient Connectivity of Remote IoT Devices in the 6G Era: A Survey

Authors: S.Plastras, D. Tsoumatidis, D. N. Skoutas, A. Rouskas, G. Kormentzas, C. Skianis

Journal: Sensors

Details: Vol. 24, No. 4, pp. 40

Publisher: MDPI

Year: 2024

Abstract
The Internet of Things (IoT) is gaining popularity and market share, driven by its ability to connect devices and systems that were previously siloed, enabling new applications and services in a cost-efficient manner. Thus, the IoT fuels societal transformation and enables groundbreaking innovations like autonomous transport, robotic assistance, and remote healthcare solutions. However, when considering the Internet of Remote Things (IoRT), which refers to the expansion of IoT in remote and geographically isolated areas where neither terrestrial nor cellular networks are available, internet connectivity becomes a challenging issue. Non-Terrestrial Networks (NTNs) are increasingly gaining popularity as a solution to provide connectivity in remote areas due to the growing integration of satellites and Unmanned Aerial Vehicles (UAVs) with cellular networks. In this survey, we provide the technological framework for NTNs and Remote IoT, followed by a classification of the most recent scientific research on NTN-based IoRT systems. Therefore, we provide a comprehensive overview of the current state of research in IoRT and identify emerging research areas with high potential. In conclusion, we present and discuss 3GPP’s roadmap for NTN standardization, which aims to establish an energy-efficient IoRT environment in the 6G era.
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On the Interplay between Deadline-Constrained Traffic and the Number of Allowed Retransmissions in Random Access Networks

Authors: N. Nomikos, T. Charalambous, R. Wichman, Y. A. Pignolet, N Pappas

Journal: Entropy

Details: Vol. 26, No. 8

Publisher: MDPI

Year: 2024

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On the leakage-rate performance of untrusted relay-aided NOMA under co-channel interference

Authors: V. Ozduran, N. Nomikos

Journal: Telecommunication Systems

Details: Vol. 85, pp. 67-86

Publisher: Springer Nature

Year: 2024

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On the Performance of Uplink Power-Domain NOMA with Imperfect CSI and SIC in 6G Networks

Authors: V. Ozduran, M. Mohammadi, N. Nomikos, I. Ansari, P. Trakadas

Journal: Journal of Communications and Networks

Details: Vol. 26, No. 4, pp. 445-460

Publisher: IEEE/KICS

Year: 2024

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Performance analysis of inverse successive interference cancellation in NOMA-based communications

Authors: V. Ozduran, N. Nomikos

Journal: Wireless Networks

Details: Vol. 30, pp. 1893–1907

Publisher: Springer Nature

Year: 2024

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Relay-Aided Uplink NOMA Under Non-Orthogonal CCI and Imperfect SIC in 6G Networks, Open Journal of Vehicular Technology

Authors: V. Ozduran, N. Nomikos, E. Nasab, I. Ansari, P. Trakadas

Journal: Open Journal of Vehicular Technology

Details: Vol. 5, pp. 658-680

Publisher: IEEE

Year: 2024

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Sailing into the Future: Technologies, Challenges, and Opportunities for Maritime Communication Networks in the 6G Era

Authors: G. Xylouris, N. Nomikos, A. Kalafatelis, A. Giannopoulos, S. Spantideas, P. Trakadas

Journal: Frontiers in Communications and Networks

Details: Vol. 5

Publisher: Frontiers

Year: 2024

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Smart Agriculture and Greenhouse Gas Emission Mitigation: A 6G-IoT Perspective

Authors: S. Polymeni, D. N. Skoutas, P. Sarigiannidis, G. Kormentzas, C. Skianis

Journal: Electronics

Details: Vol. 13, No. 8, pp. 1480

Publisher: MDPI

Year: 2024

Abstract
Smart farming has emerged as a promising approach to address the agriculture industry’s significant contribution to greenhouse gas (GHG) emissions. However, the effectiveness of current smart farming practices in mitigating GHG emissions remains a matter of ongoing debate. This review paper provides an in-depth examination of the current state of GHG emissions in smart farming, highlighting the limitations of existing practices in reducing GHG emissions and introducing innovative strategies that leverage the advanced capabilities of 6G-enabled IoT (6G-IoT). By enabling precise resource management, facilitating emission source identification and mitigation, and enhancing advanced emission reduction techniques, 6G-IoT integration offers a transformative solution for managing GHG emissions in agriculture. However, while smart agriculture focuses on technological applications for immediate efficiency gains, it also serves as a crucial component of sustainable agriculture by providing the tools necessary for long-term environmental supervision and resource sustainability. As a result, this study also contributes to sustainable agriculture by providing insights and guiding future advancements in smart farming, particularly in the context of 6G-IoT, to develop more effective GHG mitigation strategies for smart farming applications, promoting a more sustainable agricultural future.
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Software-Defined Radio Deployments in UAV-Driven Applications: A Comprehensive Review

Authors: E. T. Michailidis, K. Maliatsos, D. Vouyioukas

Journal: Open Journal of Vehicular Technology

Details: Vol. 5, pp. 1545-1586

Publisher: IEEE

Year: 2024

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"An Efficient Lightweight Event Detection Algorithm for On-Site Non-Intrusive Load Monitoring"

Authors: S. Kotsilitis, E. Kalligeros, E. C. Marcoulaki, I. G. Karybali

Journal: IEEE Transactions on Instrumentation and Measurement

Details: Vol. 72

Year: 2023

Abstract
Non-Intrusive Load Monitoring (NILM) aims to determine individual-appliance energy consumption with minimum cost, by decomposing aggregated electricity measurements. Although important for achieving energy conservation and cost minimization, NILM requires high-frequency sampling rates to provide accurate results. This requirement significantly increases the need for storage and computational resources in the electric utility’s fog/ cloud infrastructure, and for bandwidth on the customer’s side. To resolve these issues, on-site disaggregation, i.e., on the monitoring device, can be employed. However, to keep device-cost low, lightweight NILM algorithms are needed. To this end, a lightweight event-detection algorithm designed to ease on-site implementation, on either software or hardware, is proposed. Event detection is the first, critical half of the well-established event-based NILM approach; it identifies appliance state changes (events). Although a few lightweight event-detection techniques, utilizing high-frequency data, have been presented in the literature, their performance is relatively low in complex-load cases. The proposed algorithm utilizes simple-to-compute features and employs multiple simple criteria to declare an event as detected, and slope-coefficient inspection to identify steady states. Moreover, it can detect events with very small time difference between them. Comparisons show that its performance is superior even against more complex event-detection approaches, while its low computational cost is also verified.
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A Machine Learning based Motor and Cognitive Assessment Tool Using in-Game Data from the GAME2AWE Platform

Authors: M. Danousis, C. Goumopoulos

Journal: Informatics

Details: Vol. 10, No. 3

Publisher: MDPI

Year: 2023

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A Survey on UAV-Aided Maritime Communications: Deployment Considerations, Applications, and Future Challenges

Authors: N. Nomikos, P. Gkonis, P. Bithas, P. Trakadas

Journal: Open Journal of the Communications Society

Details: Vol. 4, pp. 56-78

Publisher: IEEE

Year: 2023

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A Systematic Review on Semantic Interoperability in the IoE-enabled Smart Cities

Authors: A. Platsios, K. Kotis, C. Goumopoulos

Journal: Internet of Things

Publisher: Elsevier

Year: 2023

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Empowering 6G Maritime Communications with Distributed Intelligence and Over-the-Air Model Sharing

Authors: M. Zetas, S. Spantideas, A. Giannopoulos, N. Nomikos, P. Trakadas

Journal: Frontiers in Communications and Networks

Details: Vol. 4

Publisher: Frontiers

Year: 2023

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Feasibility and Acceptance of Augmented and Virtual Reality Exergames to Train Motor and Cognitive Skills of Elderly

Authors: C. Goumopoulos, E. Drakakis, G. Dimitrios

Journal: Computers

Details: Vol. 12, No. 3

Publisher: MDPI

Year: 2023

Abstract
The GAME2AWE platform aims to provide a versatile tool for elderly fall prevention through exergames that integrate exercises, and simulate real-world environments and situations to train balance and reaction time using augmented and virtual reality technologies. In order to lay out the research area of interest, a review of the literature on systems that provide exergames for the elderly utilizing such technologies was conducted. The proposed use of augmented reality exergames on mobile devices as a complement to the traditional Kinect-based approach is a method that has been examined in the past with younger individuals in the context of physical activity interventions, but has not been studied adequately as an exergame tool for the elderly. An evaluation study was conducted with seniors, using multiple measuring scales to assess aspects such as usability, tolerability, applicability, and technology acceptance. In particular, the Unified Theory of Acceptance and Use of Technology (UTAUT) model was used to assess acceptance and identify factors that influence the seniors’ intentions to use the game platform in the long term, while the correlation between UTAUT factors was also investigated. The results indicate a positive assessment of the above user experience aspects leveraging on both qualitative and quantitative collected data.
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Feasibility and Effects of Cognitive Training with the COGNIPLAT Game Platform in Elderly with Mild Cognitive Impairment: Pilot Randomized Controlled Trial

Authors: C. Goumopoulos, G. Skikos, M. Frounta

Journal: Games for Health Journal

Publisher: Mary Ann Liebert, Inc.

Year: 2023

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Human fall detection using mmWave radars: a cluster-assisted experimental approach

Authors: H. K. Armeniakos, V. Nikolaidis, V. Tsekenis, K. Maliatsos, P. Bithas, A. G. Kanatas

Journal: Journal of Ambient Intelligence and Humanized Computing

Details: Vol. 14, pp. 11657–11669

Publisher: Springer

Year: 2023

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Performance Analysis of Uplink Non-Orthogonal Multiple Access in the Presence of Co-Channel Interference

Authors: V. Ozduran, I. Ansari, M. Mohammadi, N. Nomikos

Journal: Transactions on Vehicular Technology

Details: Vol. 72, No. 9, pp. 11590-11602

Publisher: IEEE

Year: 2023

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S2NetM: A Semantic Social Network of Things Middleware for Developing Smart and Collaborative IoT-Based Solutions

Authors: A. Platsios, D. Lymperis, C. Goumopoulos

Journal: Future Internet

Details: Vol. 15, No. 6

Publisher: MDPI

Year: 2023

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SEDIA: A Platform for Semantically Enriched IoT Data Integration and Development of Smart City Applications

Authors: D. Lymperis, C. Goumopoulos

Journal: Future Internet

Details: Vol. 15, No. 8

Publisher: MDPI

Year: 2023

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Smart City Middleware: A Survey and a Conceptual Framework

Authors: C. Goumopoulos

Journal: IEEE Access

Publisher: IEEE

Year: 2023

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The Impact of 6G-IoT Technologies on the Development of Agriculture 5.0: A Review

Authors: S. Polymeni, S.Plastras, D. N. Skoutas, G. Kormentzas, C. Skianis

Journal: Electronics

Details: Vol. 12, No. 12, pp. 24

Publisher: MDPI

Year: 2023

Abstract
Throughout human history, agriculture has undergone a series of progressive transfor-
mations based on ever-evolving technologies in an effort to increase productivity and profitability.
Over the years, farming methods have evolved significantly, progressing from Agriculture 1.0, which
relied on primitive tools, to Agriculture 2.0, which incorporated machinery and advanced farming
practices, and subsequently to Agriculture 3.0, which emphasized mechanization and employed
intelligent machinery and technology to enhance productivity levels. To further automate and
increase agricultural productivity while minimizing agricultural inputs and pollutants, a new ap-
proach to agricultural management based on the concepts of the fourth industrial revolution is being
embraced gradually. This approach is referred to as “Agriculture 4.0” and is mainly implemented
through the use of Internet of Things (IoT) technologies, enabling the remote control of sensors and
actuators and the efficient collection and transfer of data. In addition, fueled by technologies such
as robotics, artificial intelligence, quantum sensing, and four-dimensional communication, a new
form of smart agriculture, called “Agriculture 5.0,” is now emerging. Agriculture 5.0 can exploit
the growing 5G network infrastructure as a basis. However, only 6G-IoT networks will be able
to offer the technological advances that will allow the full expansion of Agriculture 5.0, as can be
inferred from the relevant scientific literature and research. In this article, we first introduce the
scope of Agriculture 5.0 as well as the key features and technologies that will be leveraged in the
much-anticipated 6G-IoT communication systems. We then highlight the importance and influence
of these developing technologies in the further advancement of smart agriculture and conclude with
a discussion of future challenges and opportunities.
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A Survey on Reinforcement Learning- Aided Caching in Heterogeneous Mobile Edge Networks

Authors: N. Nomikos, S. Zoupanos, T. Charalambous, I. Krikidis

Journal: Access

Publisher: IEEE

Year: 2022

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Bandit-Based Power Control in Full-Duplex Cooperative Relay Networks With Strict-Sense Stationary and Non-Stationary Wireless Communication Channels

Authors: N. Nomikos, S. Talebi, T. Charalambous, R. Wichman

Journal: Open Journal of the Communications Society

Details: Vol. 3, pp. 366-378

Publisher: IEEE

Year: 2022

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FINDEAS: A FinTech-based Approach on Designing and Assessing IoT Systems

Authors: S. Polymeni, D. N. Skoutas, G. Kormentzas, C. Skianis

Journal: IEEE Internet of Things Journal

Publisher: IEEE

Year: 2022

Information Freshness and Packet Drop Rate Interplay in a Two-User Multi-Access Channel

Authors: E. Fountoulakis, T. Charalambous, N. Nomikos, A. Ephremides, N. Pappas

Journal: Journal of Communications and Networks

Details: Vol. 24, No. 3, pp. 357-364

Publisher: IEEE/KICS

Year: 2022

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Mental Fatigue Detection Using a Wearable Commodity Device and Machine Learning

Authors: C. Goumopoulos, N. Potha

Journal: Journal of Ambient Intelligence and Humanized Computing

Publisher: Springer

Year: 2022

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Performance analysis of power-domain non-orthogonal multiple access for full-duplex two-way relaying

Authors: V. Ozduran, N. Mahmood, N. Nomikos

Journal: Transactions on Emerging Telecommunications Technologies

Details: Vol. 33

Publisher: Wiley

Year: 2022

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Secure UAV-Aided Mobile Edge Computing for IoT: A Review

Authors: E. T. Michailidis, K. Maliatsos, D. N. Skoutas, D. Vouyioukas, C. Skianis

Journal: Access

Publisher: IEEE

Year: 2022

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"Thwarting All Logic Locking Attacks: Dishonest Oracle with Truly Random Logic Locking"

Authors: N. Limaye, E. Kalligeros, N. Karousos, I. G. Karybali, O. Sinanoglu

Journal: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

Details: Vol. 40, No. 9, pp. 1740-1753

Year: 2021

Abstract
While logic locking is a promising defense to protect hardware designs, many attacks have been shown to undermine its security by retrieving the secret key. All the powerful attacks rely on a working chip, i.e., an oracle, and in particular, heavily use the test access. The proposed technique DisORC turns the oracle into a dishonest one whenever a potential attack is detected. DisORC works on the premise that structural testing of chips need not be performed with the correct functionality. We implement this capability by adding circuitry around a logic-locked design that reconfigures its functionality upon detecting access to scan chains. Any attempt to access scan chains disconnects the secret key from the circuit, and clears all of its traces, isolating and securing it. We also pair this defense with a truly random logic locking (TRLL) scheme that makes random decisions in inserting key gates and retaining signal polarities without relying on any logic synthesis technique to perform bubble pushing. Any netlist analysis-based attack, known or anticipated, will then learn nothing useful to infer the key values. The combined defense DisORC + TRLL thwarts oracle-based and netlist analysis-based attacks while delivering sufficient corruption levels at the outputs. We also show that the proposed defense is cost effective and can be integrated into the design flow easily. The proposed logic locking defense provides protection against untrusted foundry, testing facility, end users, and any combination of them colluding together.
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A Low-Complexity Reconfigurable Multi- Antenna Technique for Non-Terrestrial Networks

Authors: K. Maliatsos, P. Bithas, A. G. Kanatas

Journal: Frontiers in Communications and Networks

Details: Vol. 2

Publisher: Frontiers

Year: 2021

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Communication Network Standards for Smart Grid Infrastructures

Authors: K. Demertzis, K. Tsiknas, D. Taketzis, D. N. Skoutas, C. Skianis, L. Iliadis, K. Zoiros

Journal: Network

Details: Vol. 1, No. 2, pp. 132-145

Publisher: MDPI

Year: 2021

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HST-NNC: A Novel Hybrid Satellite-Terrestrial Communication with NOMA and Network Coding Systems

Authors: M. Karavolos, N. Nomikos, D. Vouyioukas, P. Mathiopoulos

Journal: Open Journal of the Communications Society

Details: Vol. 2, pp. 887-898

Publisher: IEEE

Year: 2021

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LoLA4SOR: Leveraging Successive Transmissions for Low-Latency Buffer-Aided Opportunistic Relay Networks

Authors: N. Nomikos, T. Charalambous, N. Pappas, D. Vouyioukas, R. Wichman

Journal: Open Journal of the Communications Society

Details: Vol. 2, pp. 1041-1054

Publisher: IEEE

Year: 2021

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Mild Cognitive Impairment Detection Using Machine Learning Models Trained on Data Collected from Serious Games

Authors: C. Karapapas, C. Goumopoulos

Journal: Applied Sciences

Details: Vol. 11, pp. 8184

Publisher: MDPI

Year: 2021

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Mixed FSO/RF Communications in UAV-enabled Multi-User MIMO Networks

Authors: E. T. Michailidis, P. Bithas, N. Nomikos, D. Vouyioukas, A. G. Kanatas

Journal: Physical Communication

Details: Vol. 49

Publisher: Elsevier

Year: 2021

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When Buffer-Aided Relaying Meets Full-Duplex and NOMA

Authors: N. Nomikos, T. Charalambous, D. Vouyioukas, G. K. Karagiannidis

Journal: Wireless Communications

Details: Vol. 28, No. 1, pp. 68-73

Publisher: IEEE

Year: 2021

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A Framework for Pervasive Computing Applications based on Smart Objects and End User Development

Authors: C. Goumopoulos, Mavrommati I.

Journal: Journal of Systems and Software

Details: Vol. 162

Publisher: Elsevier

Year: 2020

Abstract
Pervasive Computing (PerComp) research remains to this date technology-centric, requiring more focus on utilizing human and societal intelligence. To bridge this gap we motivate the need for a conceptual framework that provides a vision for enabling end-users to participate actively in the design of PerComp applications. The framework in particular provides guidance for the development of tools that allow end-users to configure their own smart environments. It emphasizes the benefits of using Smart Objects (SOs) as components of PerComp applications under a system engineering perspective and the benefits of using affordances as dynamic connectable capabilities under a user experience perspective. A generic application model is developed within the framework that manifests the concepts governing the structure and operation of applications composed by connecting SOs together and adhering to a rule-based behavior. A multi-layered software mediator is defined to provide a platform for the runtime support of such PerComp applications. Theoretical foundations for the key concepts adopted regarding the interaction design and system engineering perspectives are discussed and the results of a user evaluation study focusing on the perceived usability of the high-level conceptual models and the developed tools are reported.
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A Moving 5G RAN Architecture for Massive Connectivity of Mobile Users and IoT Devices

Authors: N. Nomikos, E. T. Michailidis, P. Trakadas, D. Vouyioukas, H. Karl, J. Martrat, K. Papadopoulos, T. Zahariadis, S. Voliotis

Journal: Vehicular Communications

Publisher: Elsevier

Year: 2020

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A Review on IoT Frameworks Supporting Multi-Level Interoperability – The Semantic Social Network of Things Framework.

Authors: A. Platsios, C. Goumopoulos, K. Kotis

Journal: International Journal on Advances in Internet Technology

Details: Vol. 13, No. 1, pp. 46-64

Publisher: IARIA JOURNALS

Year: 2020

Abstract
The Internet of Things (IoT) paradigm advocates
the massive use of sensing and communication technologies
embedded in the physical world, which provides the potential to
collect huge volumes of data and connect them to intelligent
systems. As the number of IoT devices is increasing with
geometric progress, ensuring interoperability and handling of
the big heterogeneous data they generate is of major importance
for the development of smart applications and services. In this
context, a systematic review of contemporary IoT frameworks
based on a multi-level interoperability consideration is
performed and findings are critically discussed. Challenges and
open issues that emerge in this research area are pointed out,
and research opportunities and insights are suggested.
Motivated by the shortcomings of the current solutions to
support open, interoperable, intelligent and collaborative IoT
environments, the concept of Semantic Social Network of
Things (SSNT) is introduced. SSNT specifies the integration of
device-to-device collaborative services which semantically
enable heterogeneous objects to (socially) interact and
participate in communities of smart objects. By establishing
social relationships and taking collaborative actions, such
communities can support users to achieve their goals. A
middleware-based framework architecture is presented to enact
the SSNT abstraction, and a proof-of-concept application in the
smart agriculture domain is outlined to demonstrate important
features of this approach.
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Brain computer interface based applications for training and rehabilitation of students with neurodevelopmental disorders. A literature review

Authors: G. Papanastasiou, A. Drigas, C. Skianis, M. Lytras

Journal: Helyion

Details: Vol. 6, No. 9

Publisher: Elsevier

Year: 2020

Abstract
The aim of this article is to explore a paradigm shift on Brain Computer Interface (BCI) research, as well as on intervention best practices for training and rehabilitation of students with neurodevelopmental disorders. Recent studies indicate that BCI devices have positive impact on students\' attention skills and working memory as well as on other skills, such as visuospatial, social, imaginative and emotional abilities. BCI applications aim to emulate humans\' brain and address the appropriate understanding for each student\'s neurodevelopmental disorders. Studies conducted to provide knowledge about BCI-based intervention applications regarding memory, attention, visuospatial, learning, collaboration, and communication, social, creative and emotional skills are highlighted. Only non-invasive BCI type of applications are being investigated based upon representative, non-exhaustive and state-of-the-art studies within the field. This article examines the progress of BCI research so far, while different BCI paradigms are investigated. BCI-based applications could successfully regulate students\' cognitive abilities when used for their training and rehabilitation. Future directions to investigate BCI-based applications for training and rehabilitation of students with neurodevelopmental disorders concerning the different populations involved are discussed.
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Enhanced Integrated Satellite–Terrestrial NOMA with Cooperative Device-to-Device Communication

Authors: M. Karavolos, N. Nomikos, D. Vouyioukas

Journal: Telecom

Publisher: MDPI

Year: 2020

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Hybrid Multi-Antenna Techniques for V2X Communications— Prototyping and Experimentation

Authors: K. Maliatsos, L. Marantis, P. Bithas, A. G. Kanatas

Journal: Telecom

Details: Vol. 1, pp. 80-95

Publisher: MDPI Open Access Journal

Year: 2020

Integrating Broadcasting and NOMA in Full-Duplex Buffer-Aided Opportunistic Relay Networks

Authors: N. Nomikos, T. Charalambous, D. Vouyioukas, R. Wichman, G. K. Karagiannidis

Journal: Transactions on Vehicular Technology

Details: Vol. 69, No. 8, pp. 9157-9162

Publisher: IEEE

Year: 2020

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PID controller optimized by Big Bang-Big Crunch algorithm for the evolution of router bandwidth demand

Authors: I. Giannopoulos, A. Leros, A.P. Leros, P. Kofinas, A. Dounis

Journal: International Journal of Information Technology

Details: Vol. 12, No. 3, pp. 691-698

Publisher: Springer

Year: 2020

Real-time adaptive stochastic control of smart grid data traffic for security purposes

Authors: I. Giannopoulos, A. Leros, A.P. Leros, G. Tsaramirsis, M. Alassafi

Journal: Sustainable Cities and Society

Details: Vol. 63, pp. Art. 102473

Publisher: Elsevier

Year: 2020

Tackling Faults in the Industry 4.0 Era: A Survey of Machine-Learning Solutions and Key Aspects

Authors: N. Nomikos, A. Angelopoulos, E. T. Michailidis, P. Trakadas, A. Hatziefremidis, S. Voliotis, T. Zahariadis

Journal: Sensors

Details: Vol. 20, No. 1

Publisher: MDPI

Year: 2020

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Three-Dimensional Modeling of mmWave Doubly Massive MIMO Aerial Fading Channels

Authors: E. T. Michailidis, N. Nomikos, P. Trakadas, A. G. Kanatas

Journal: Transactions on Vehicular Technology

Details: Vol. 69, No. 2, pp. 1190-1202

Publisher: IEEE

Year: 2020

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Towards the design of an assurance framework for increasing security and privacy in connected vehicles

Authors: C. Kalloniatis, V. Diamantopoulou, K. Kotis, C. Lyvas, K. Maliatsos, M. Gay, A. G. Kanatas, C. Lambrinoudakis

Journal: International Journal of Internet of Things and Cyber-Assurance

Details: Vol. 1, No. 3-4, pp. 244-266

Publisher: Inderscience Enterprises Ltd.

Year: 2020

"Optimization and Hardware Implementation of Image and Video Watermarking for Low Cost Applications"

Authors: K. Pexaras, I. G. Karybali, E. Kalligeros

Journal: IEEE Transactions on Circuits and Systems I: Regular Papers

Details: Vol. 66, No. 6, pp. 2088-2101

Year: 2019

Abstract
The prevalence of wireless networks has made the long-term need for communications security more imperative. In various wireless applications, images and/or video constitute critical data for transmission. For their copyright protection and authentication, watermarking can be used. In many cases, the cost of wireless nodes must be kept low, which means that their processing and/or power capabilities are very limited. In such cases, low-cost hardware implementations of digital image/video watermarking techniques are necessary. However, to end up with such implementations, proper selection of watermarking techniques is not enough. For this reason, in this paper, we introduce computation optimizations of the implemented algorithm to keep the integer part of arithmetic operations at optimal size, and, hence, arithmetic units as small as possible. In addition, further analysis is performed to reduce quantization error. Three different hardware-architecture variants, two for image watermarking and one for video (pipelined), are proposed, which reutilize the already small arithmetic units in different computation steps, to further reduce implementation cost. The proposed designs compare favorably to already existing implementations in terms of area, power, and performance. Moreover, the watermarked images'/frames' errors, compared to their floating point counterparts, are very small, while robustness to various attacks is high.
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A Survey on Machine-Learning Techniques for UAV-Based Communications

Authors: N. Nomikos, P. Bithas, E. T. Michailidis, D. Vouyioukas, A. G. Kanatas

Journal: Sensors

Publisher: MDPI

Year: 2019

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An SINR-Aware Joint Mode Selection, Scheduling, and Resource Allocation Scheme for D2D Communications

Authors: P. Bithas, K. Maliatsos, F. Foukalas

Journal: IEEE Transactions on Vehicular Technology

Details: Vol. 68, No. 5, pp. 4949-4963,

Publisher: IEEE

Year: 2019

Design Concepts, Principles and Patterns in the Curriculum of the New Computing Education Era

Authors: Mavroudi, A., Fragou, O., C. Goumopoulos

Journal: Designs for Learning

Details: Vol. 11, No. 1, pp. 141–153

Publisher: Stockholm University Press

Year: 2019

Abstract
Ubiquitous Computing, Mobile Computing and the Internet of Things (collectively referred to as UMI herein) involve recent advances in technology areas such as low-cost and miniaturized processing and sensing technologies, high-bandwidth wireless networking and so on. UMI technologies can also support the recent attempts to reform computing education. Yet, to accomplish this potential, relevant UMI learning scenarios are needed. Creating such scenarios can be challenging, since this particular field of computing education is still in its infancy. This paper discusses learning design knowledge which can orientate the future design of UMI learning scenarios. Content analysis was applied on ten quality UMI-oriented learning scenarios. The scenarios were freely accessible in online platforms, and they were designed for middle school education and for the UMI domain. Two different methodological approaches were employed: the first one involved mapping the scenarios to existing predefined learning design elements (i.e. design concepts, design principles, and design patterns). The learning design elements were previously defined in an online database and they involved ubiquitous tools. The second method involved mapping the scenarios to the parameters of a UMI learning ecology. The performed analysis revealed design concepts, principles, patterns and key characteristics underpinning the selected UMI scenarios: they cater for students’ active learning and engage them in interdisciplinary projects in which students are learning across contexts in groups and solve meaningful problems that exploit the functionalities of the UMI technologies. Several recommendations concerning the creation of quality UMI learning scenarios are suggested, such as: striking a balance between conceptual understanding and 21st century lifelong learning skills, highlighting how students’ collaboration is expected to happen in a UMI scenario, providing many opportunities for instructional scaffolding and explicitly mentioning spatiotemporal aspects of the UMI scenarios. These findings could be of interest to computing education researchers, tutors, and curriculum designers who wish to design UMI oriented educational scenarios.
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Energy-Aware Clustering of CoMP-DPS Transmission Points

Authors: V. Tatsis, M. Karavolos, D. N. Skoutas, N. Nomikos, D. Vouyioukas, C. Skianis

Journal: Computer Communications

Details: Vol. 135, pp. 28-39

Publisher: Elsevier

Year: 2019

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Flex-NOMA: Exploiting Buffer-Aided Relay Selection for Massive Connectivity in the 5G Uplink

Authors: N. Nomikos, E. T. Michailidis, P. Trakadas, D. Vouyioukas, T. Zahariadis, I. Krikidis

Journal: Access

Details: Vol. 7, No. 1, pp. 88743-88755

Publisher: IEEE

Year: 2019

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Full-Duplex NOMA Transmission with Single-Antenna Buffer-Aided Relays

Authors: N. Nomikos, P. Trakadas, A. Hatziefremidis, S. Voliotis

Journal: Electronics

Publisher: MDPI

Year: 2019

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Hybrid Clouds for Data-Intensive, 5G-enabled IoT Applications: An Overview, Key Issues and Relevant Architecture

Authors: P. Trakadas, N. Nomikos, E. T. Michailidis, T. Zahariadis, F. Facca, D. Breitgand, S. Rizou, X. Masip, P. Gkonis

Journal: Sensors

Publisher: MDPI

Year: 2019

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Hybrid NOMA/OMA with Buffer Aided Relay Selection in Cooperative Networks

Authors: N. Nomikos, T. Charalambous, D. Vouyioukas, G. K. Karagiannidis, R. Wichman

Journal: Journal of Selected Areas in Signal Processing

Details: Vol. 13, No. 3, pp. 524-537

Publisher: IEEE

Year: 2019

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Optimal 3-D Aerial Relay Placement for Multi-User MIMO Communications

Authors: E. T. Michailidis, N. Nomikos, P. Bithas, D. Vouyioukas, A. G. Kanatas

Journal: Transactions on Aerospace and Electronic Systems

Publisher: IEEE

Year: 2019

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STEM Oriented On Line Platforms Embracing the Community of Practice Model: A Comparative Study and Design Guidelines

Authors: Fragou, O., C. Goumopoulos, C. Tsompanos

Journal: Journal of Universal Computer Science

Publisher: J.UCS Consortium

Year: 2019

Stress Detection in Seniors Using Biosensors and Psychometric Tests

Authors: C. Goumopoulos, Menti E.

Journal: Procedia Computer Science

Details: Vol. 152, pp. 18-27

Publisher: Elsevier

Year: 2019

Abstract
Stress management is related to improved senior well-being and health. The purpose of this work is to identify individual characteristics that suggest the existence of stress and associate these characteristics with features extracted from biometric signals. For identifying these characteristics, on the one hand emotional/psychological measurements are collected using specific questionnaires and on the other hand features are extracted from biosignals collected using wireless sensors. The results of a pilot study with the participation of 12 seniors (mean age 59.7 ±5.8) are reported. Our results indicate that electrodermal activity and heart rate variability features are valid stress indicators for seniors.
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Synchronization of Data Measurements in Wireless Sensor Networks for IoT Applications

Authors: K. Skiadopoulos, A. Tsipis, K. Giannakis, G. Koufoudakis, E. Christopoulou, K. Oikonomou, G. Kormentzas, I. Stavrakakis

Journal: Ad Hoc Networks,

Details: Vol. 89, pp. 47-57

Publisher: Elsevier

Year: 2019

A High Precision, Wireless Temperature Measurement System for Pervasive Computing Applications

Authors: C. Goumopoulos

Journal: Sensors

Details: Vol. 18, No. 10, pp. 3445

Publisher: MDPI

Year: 2018

Abstract
This paper describes the design and calibration of a highly accurate temperature measurement system for pervasive computing applications. A negative temperature coefficient (NTC) thermistor with high resistance tolerance is interfaced through a conditioning circuit to a 12-bit digital converter of a wireless microcontroller. The system is calibrated to minimize the effect of component uncertainties and achieves an accuracy of ±0.03 °C on average (±0.05 °C in worst cases) in a 5 °C to 45 °C range. The calibration process is based on a continuous temperature sweep, while calibration data are simultaneously logged to reduce the delays and cost of conventional calibration approaches. An uncertainty analysis is performed to support the validity of the reported performance results. The described approach for interfacing the thermistor to the hardware platform can be straightforwardly adjusted for different thermistors, temperature ranges/accuracy levels/resolutions, and voltage ranges. The low power communication combined with the energy consumption optimization adopted enable an operation to be autonomic for several months to years depending on the application’s measurement frequency requirements. The system cost is approximately $45 USD in components, while its design and compact size allow its integration with extended monitoring systems in various pervasive computing environments. The system has been thoroughly tested and validated in a field trial concerning a precision agriculture application and is currently used in a health monitoring application.
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Delay- and Diversity-Aware Buffer-Aided Relay Selection Policies in Cooperative Networks

Authors: N. Nomikos, D. Poulimeneas, T. Charalambous, I. Krikidis, D. Vouyioukas, M. Johansson

Journal: Access

Publisher: IEEE

Year: 2018

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Low-Complexity Buffer-Aided Link Selection with Outdated CSI and Feedback Errors

Authors: N. Nomikos, T. Charalambous, D. Vouyioukas, G. K. Karagiannidis

Journal: Transactions on Communications

Details: Vol. 66, No. 8, pp. 3694-3706

Publisher: IEEE

Year: 2018

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Patient-centric ICTs based healthcare for students with learning, physical and/or sensory disabilities

Authors: G. Papanastasiou, A. Drigas, C. Skianis, M. Lytras, E.Papanastasiou

Journal: Telematics and Informatics

Details: Vol. 35, No. 4, pp. 654-664

Publisher: Elsevier

Year: 2018

Abstract
The purpose of this review article is to explore a new paradigm on healthcare assessment and intervention practices for students with learning, physical and/or sensory disabilities. The perspective presented here is regarded as patient centric and relies on ICTs, in order to address evidence–based treatment and care, meeting every individual’s health profile, with regard to his or her needs, preferences, goals and culture. Patient-centric ICTs based approach has an impact on healthcare systems, introducing a multi-disciplinary care planning that overcomes individual, professional and organizational barriers, reduces anxiety and establishes better understanding with the student at the center.

Generally, results show the impact of the interoperability of healthcare information between patients’ healthcare record and information systems which facilitate healthcare systems to be lifesaving if available at the time of medical examination. When medical treatment is combined with ICTs based methods and applications such as Serious Games, Mobile Assistive Technologies applications, Telehealth Systems and Virtual Training, patients with learning, physical and/or sensory disabilities can benefit from a cost-effective and flexible network model while having their customized needs fully examined and resolved.

The articles presented within this review demonstrate that ICTs based patient-centeredness for students with learning, physical and/or sensory disabilities is associated with better (functional) outcomes leading to quality of life and inclusion, improved quality of care, fewer problem behaviors, higher levels of health-related autonomy and greater patient satisfaction.
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Power Adaptation in Buffer-Aided Full-Duplex Relay Networks with Statistical CSI

Authors: N. Nomikos, T. Charalambous, D. Vouyioukas, R. Wichman, G. K. Karagiannidis

Journal: Transactions on Vehicular Technology

Details: Vol. 67, No. 8, pp. 7846-7850

Publisher: IEEE

Year: 2018

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Relay Pair Selection with Source Precoding in Buffer-Aided Successive Opportunistic Relaying

Authors: T. Charalambous, S. M. Kim, N. Nomikos, M. Bengtsson, M. Johansson

Journal: Ad Hoc Networks

Publisher: Elsevier

Year: 2018

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Virtual and augmented reality effects on K-12, higher and tertiary education students’ twenty-first century skills

Authors: G. Papanastasiou, A. Drigas, C. Skianis, M. Lytras, E.Papanastasiou

Journal: Virtual Reality

Details: pp. 1-12

Publisher: Springer

Year: 2018

Abstract
The purpose of this review article is to present state-of-the-art approaches and examples of virtual reality/augmented reality (VR/AR) systems, applications and experiences which improve student learning and the generalization of skills to the real world. Thus, we provide a brief, representative and non-exhaustive review of the current research studies, in order to examine the effects, as well as the impact of VR/AR technologies on K-12, higher and tertiary education students’ twenty-first century skills and their overall learning. According to the literature, there are promising results indicating that VR/AR environments improve learning outcomes and present numerous advantages of investing time and financial resources in K-12, higher and tertiary educational settings. Technological tools such as VR/AR improve digital-age literacy, creative thinking, communication, collaboration and problem solving ability, which constitute the so-called twenty-first century skills, necessary to transform information rather than just receive it. VR/AR enhances traditional curricula in order to enable diverse learning needs of students. Research and development relative to VR/AR technology is focused on a whole ecosystem around smart phones, including applications and educational content, games and social networks, creating immersive three-dimensional spatial experiences addressing new ways of human–computer interaction. Raising the level of engagement, promoting self-learning, enabling multi-sensory learning, enhancing spatial ability, confidence and enjoyment, promoting student-centered technology, combination of virtual and real objects in a real setting and decreasing cognitive load are some of the pedagogical advantages discussed. Additionally, implications of a growing VR/AR industry investment in educational sector are provided. It can be concluded that despite the fact that there are various barriers and challenges in front of the adoption of virtual reality on educational practices, VR/AR applications provide an effective tool to enhance learning and memory, as they provide immersed multimodal environments enriched by multiple sensory features.
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Development and Evaluation of a Mobile Application Suite for Enhancing the Social Inclusion and Well-Being of Seniors

Authors: C. Goumopoulos, Papa I., Stavrianos A.

Journal: Informatics

Details: Vol. 4, No. 3, pp. 15

Publisher: MDPI

Year: 2017

Abstract
Smart mobile devices, due to their ubiquitous nature and high level penetration in everyday life, can be a key component of an Ambient Assisted Living system to improve the quality of life of older people. This paper presents the development and evaluation of Senior App Suite, a system created for assisting seniors’ personal independence and social inclusion. The system integrates mobile computing combined with web and service-oriented technologies to offer a mobile application suite that seniors can easily use to access services, spanning various application areas such as social networking, emergency detection and overall well-being. The research hypothesis is that using such services can be beneficial for decreasing social isolation. There is quantitative indication that this assumption is realistic backed up also by the qualitative analysis from the user’s feedback derived during a pilot study (n = 22) suggesting that Senior App Suite can motivate people in new activities, maintain connection with social ties, give joy and self-confidence, and increase the frequency and quality of social interactions. Our contribution is a detailed methodology spanning the research, design, development, and evaluation of a solution that aims to improve the quality of life of seniors while addressing open issues identified in related initiatives.
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Dynamic Knowledge-Based Analysis in Nonsecure 5G Green Environments Using Contextual Data

Authors: A. Nieto, N. Nomikos, J. Lopez, C. Skianis

Journal: Systems Journal

Details: Vol. 11, No. 4, pp. 2479-2489

Publisher: IEEE

Year: 2017

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Serious games in K-12 education: Benefits and impacts on students with attention, memory and developmental disabilities

Authors: G. Papanastasiou, A. Drigas, C. Skianis, M. Lytras

Journal: Program

Details: Vol. 51, No. 4, pp. 424-440

Publisher: Emerald Publishing Limited

Year: 2017

Abstract
Purpose
The purpose of this paper is to explore the integration of serious games (SGs) in the area of special educational needs in the last ten years (2007-2017).

Design/methodology/approach
SGs indicate positive effects on students with special educational needs and promote a multi-sensory style of learning.

Findings
Research showed that SGs are able to keep K-12 education students with attention, memory and developmental disabilities engaged in classroom facilities scaffolding their learning through increased motivation, independence, autonomy and resultant self-esteem.

Research limitations/implications
Time constraints, cost and availability of appropriate games as well as the small sample of the individuals being investigated are some of the research limitations the paper refers to.

Practical implications
Learning through SGs has educational values that are based on learning concepts intrinsically motivating.

Social implications
Students with attention, memory and developmental disabilities demonstrate characteristics of engagement, creativity, control and communication.

Originality/value
SGs-based learning has proven its value added to students with attention, memory and executive control difficulties as well as mental or developmental disabilities engaging students better than when using traditional methods.
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Serious Games in Preschool and Primary Education: Benefits And Impacts on Curriculum Course Syllabus

Authors: G. Papanastasiou, A. Drigas, C. Skianis

Journal: International Journal of Emerging Technologies in Learning (iJET)

Details: Vol. 12, No. 1, pp. 48-56

Year: 2017

Abstract
Serious Games (SGs) indicate positive effects on Preschool and Primary school students and promote a multi sensory style of learning. This review paper explores the integration of Serious Games in the area of Preschool and Primary Education, in the last decade (2006-2016). The studies were carried out on Preschool and Primary school settings, respectively. Research showed that Serious Games are able to keep all students engaged in classroom facilities, scaffolding their learning through increased motivation, independence, autonomy and resultant self-esteem. Serious Games Based Learning (GBL) has proven its added value in almost every aspect of the curriculum.
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Smart Cities: Recent Trends, Methodologies, and Applications

Authors: D. Gavalas, P. Nicopolitidis, A. Kameas, C. Goumopoulos, Bellavista P., Lambrinos L., Guo B.

Journal: Wireless Communications and Mobile Computing

Details: Vol. 2017, No. 7090963, pp. 2

Publisher: Hindawi

Year: 2017

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A Pervasive Computing Curriculum via Distance Learning

Authors: C. Goumopoulos, P. Nicopolitidis, D. Gavalas, A. Kameas

Journal: Continuing Engineering Education and Life-Long Learning

Details: Vol. 27, No. 1/2, pp. 122-146

Publisher: Inderscience Publishers

Year: 2016

Abstract
Engineering of pervasive computing (PerComp) systems is a new scientific field and from an educational perspective needs to draw from a large number of knowledge domains. The appearance of related courses in computer science curricula has a decade history, but the growth of interest has led in recent years to the design of more advanced PerComp educational programs. In this paper we present our experiences in organizing, managing and teaching a PerComp curriculum at a postgraduate level since 2010 using distance learning methodologies in the Hellenic Open University (HOU). We discuss the distinct characteristics and related challenges of distance education and how these characteristics affected program organization, educational material structuring, laboratory courses delivering, and student assessment. We report our main findings and conclusions extracted by an online survey filled by students enrolled in the program, discuss the lessons learned and also provide a number of suggestions for further development.
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A stochastic model with an adaptive proportional controller for the evolution of user-router bandwidth demand for quality of service aspects

Authors: I. Giannopoulos, A. Leros, A.P. Leros, G. Tsaramirsis

Journal: Ad Hoc & Sensor Wireless Networks

Details: Vol. 30, No. 1-2, pp. 65--81

Year: 2016

A Survey on Buffer-Aided Relay Selection

Authors: N. Nomikos, T. Charalambous, I. Krikidis, D. N. Skoutas, D. Vouyioukas, M. Johansson, C. Skianis

Journal: Communications Surveys & Tutorials

Details: Vol. 18, No. 2, pp. 1073-1097

Publisher: IEEE

Year: 2016

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Efficient entertainment services provision over a novel network architecture

Authors: Y. Kryftis, G. Mastorakis, C. X. Mavromoustakis, J.M.Batalla, E. Pallis, G. Kormentzas

Journal: IEEE Wireless Communications

Details: Vol. 23, No. 1, pp. 14-21

Year: 2016

The Bivariate Double Rayleigh Distribution for Multichannel Time-Varying Systems

Authors: P. Bithas, K. Maliatsos, A. G. Kanatas

Journal: IEEE Wireless Communications Letters

Details: Vol. 5, pp. 524 - 527

Publisher: IEEE

Year: 2016

A Buffer-aided Successive Opportunistic Relay Selection Scheme with Power Adaptation and Inter-Relay Interference Cancellation for Cooperative Diversity Systems

Authors: N. Nomikos, T. Charalambous, I. Krikidis, D. N. Skoutas, D. Vouyioukas, M. Johansson

Journal: Transactions on Communications

Details: Vol. 63, No. 5, pp. 1623-1634

Publisher: IEEE

Year: 2015

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GAIA Bus: Cloud Computing Services for Agro-Food Chain

Authors: G. Kormentzas

Journal: International Journal of Wireless Networks and Broadband Technologies (IJWNBT)

Details: Vol. 4, No. 1, pp. 16-28.

Year: 2015

Localization Error Modeling of Hybrid Fingerprint-Based Techniques for Indoor Ultra- Wideband Systems

Authors: E. Bogdani, D. Vouyioukas, N. Nomikos

Journal: Telecommunication Systems

Publisher: Springer

Year: 2015

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Modeling Buffer-Aided Relay Selection in Networks with Direct Transmission Capability

Authors: T. Charalambous, N. Nomikos, I. Krikidis, D. Vouyioukas, M. Johansson

Journal: Communications Letters

Details: Vol. 19, No. 4, pp. 649-652

Publisher: IEEE

Year: 2015

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Relay selection for secure 5G green communications

Authors: N. Nomikos, A. Nieto, P. Makris, D. N. Skoutas, D. Vouyioukas, P. Rizomiliotis, J. Lopez, C. Skianis

Journal: Telecommunication Systems

Details: Vol. 59, pp. 169-187

Publisher: Springer

Year: 2015

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Wireless Femto-Relays: A new model for small cell deployments

Authors: N. Nomikos, P. Makris, D. N. Skoutas, D. Vouyioukas, C. Skianis

Journal: International Journal of Wireless Networks and Broadband Technologies

Details: Vol. 4, No. 1, pp. 45-61

Publisher: IGI Global

Year: 2015

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A Large-Scale Distributed Federated Experimental Facility Offering Simulation Services for Next Generation Wireless Networks

Authors: G. Kormentzas

Journal: Information Engineering (IE)

Details: Vol. 3, pp. 1-11

Year: 2014

A prototype cognitive radio architecture for TVWS exploitation under the real time secondary spectrum market policy

Authors: A. Bourdena, E. Pallis, G. Kormentzas, G. Mastorakis

Journal: Physical Communication, Elsevier

Details: Vol. 10, pp. 159-168

Year: 2014

A Resource Intensive Traffic-Aware Scheme using Energy-efficient Routing in Cognitive Radio Networks

Authors: A. Bourdena, C. X. Mavromoustakis, G. Kormentzas, E. Pallis, G. Mastorakis, C. X. Mavromoustakis

Journal: Future Generation Computer Systems, Elsevier,

Details: Vol. 39, pp. 16-28

Year: 2014

An Energy-Aware Scheme for Efficient Spectrum Utilization in a 5G Mobile Cognitive Radio Network Architecture

Authors: C. X. Mavromoustakis, A. Bourdena, G. Mastorakis, E. Pallis, G. Kormentzas

Journal: Springer Telecommunication Systems Journal

Year: 2014

Automated Zone-Specific Irrigation with Wireless Sensor/Actuator Network and Adaptable Decision Support

Authors: C. Goumopoulos, B. Oflynn, A. Kameas

Journal: Computers and Electronics in Agriculture

Details: Vol. 105, pp. 20–33

Publisher: Elsevier

Year: 2014

Abstract
Precision irrigation based on the “speaking plant” approach can save water and maximize crop yield, but implementing irrigation control can be challenging in system integration and decision making. In this paper we describe the design of an adaptable decision support system and its integration with a wireless sensor/actuator network (WSAN) to implement autonomous closed-loop zone-specific irrigation. Using an ontology for defining the application logic emphasizes system flexibility and adaptability and supports the application of automatic inferential and validation mechanisms. Furthermore, a machine learning process has been applied for inducing new rules by analyzing logged datasets for extracting new knowledge and extending the system ontology in order to cope, for example, with a sensor type failure or to improve the accuracy of a plant state diagnosis. A deployment of the system is presented for zone specific irrigation control in a greenhouse setting. Evaluation of the developed system was performed in terms of derivation of new rules by the machine learning process, WSN performance and mote lifetime. The effectiveness of the developed system was validated by comparing its agronomic performance to traditional agricultural practices.
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Capacity Maximization through Energy-Aware Multi-Mode Relaying

Authors: N. Nomikos, D. N. Skoutas, D. Vouyioukas, C. Verikoukis, C. Skianis

Journal: Wireless Personal Communications

Details: Vol. 74, No. 1, pp. 83-99

Publisher: Springer

Year: 2014

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Efficient Radio Resource Management Algorithms in Opportunistic Cognitive Radio Networks

Authors: A. Bourdena, E. Pallis, G. Kormentzas, G. Mastorakis

Journal: Emerging Telecommunication Technologies, Wiley

Details: Vol. 25, No. 8, pp. 785-797

Year: 2014

Elaborate Analysis and Design of Filter Bank based Sensing for wideband Cognitive Radios

Authors: K. Maliatsos, A. Adamis, A. G. Kanatas

Journal: EURASIP Journal on Advances in Signal Processing

Details: Vol. 82

Publisher: Springer

Year: 2014

Performance Evaluation of Beamspace MIMO Systems with Channel Estimation in Realistic Environments

Authors: K. Maliatsos, P. Vasileiou, A. G. Kanatas

Journal: Journal of Cyber Security and Mobility

Details: Vol. 2, pp. 265-290

Publisher: River Publishers

Year: 2014

"Merged Switch Allocation and Traversal in Network-On-Chip Switches"

Authors: G. Dimitrakopoulos, E. Kalligeros, K. Galanopoulos

Journal: IEEE Transactions on Computers

Details: Vol. 62, No. 10, pp. 2001-2012

Year: 2013

Abstract
Large systems-on-chip (SoCs) and chip multiprocessors (CMPs), incorporating tens to hundreds of cores, create a significant integration challenge. Interconnecting a huge amount of architectural modules in an efficient manner, calls for scalable solutions that would offer both high throughput and low-latency communication. The switches are the basic building blocks of such interconnection networks and their design critically affects the performance of the whole system. So far, innovation in switch design relied mostly to architecture-level solutions that took for granted the characteristics of the main building blocks of the switch, such as the buffers, the routing logic, the arbiters, the crossbar’s multiplexers, and without any further modifications, tried to reorganize them in a more efficient way. Although such pure high-level design has produced highly efficient switches, the question of how much better the switch would be if better building blocks were available remains to be investigated. In this paper, we try to partially answer this question by explicitly targeting the design from scratch of new soft macros that can handle concurrently arbitration and multiplexing and can be parameterized with the number of inputs, the data width, and the priority selection policy. With the proposed macros, switch allocation, which employs either standard round robin or more sophisticated arbitration policies with significant network-throughput benefits, and switch traversal, can be performed simultaneously in the same cycle, while still offering energy-delay efficient implementations.
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A Context Aware Framework for the Efficient Integration of Femtocells in IP and Cellular Infrastructures

Authors: P. Makris, N. Nomikos, D. N. Skoutas, D. Vouyioukas, C. Skianis, Jie Zhang, C. Verikoukis

Journal: Journal on Wireless Communications and Networking

Publisher: EURASIP

Year: 2013

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A Routing Protocol for Enhanced Efficiency in Cognitive Radio Networks

Authors: A. Bourdena, G. Mastorakis, E. Pallis, G. Kormentzas

Journal: Journal of Communications and Computers

Details: Vol. 10, pp. 675-685

Year: 2013

Distance Learning: A Postgraduate PerCom Program

Authors: A. Kameas, D. Gavalas, C. Goumopoulos, P. Nicopolitidis, G. Giaglis

Journal: IEEE Pervasive Computing

Details: Vol. 12, No. 2, pp. 83-85

Publisher: IEEE

Year: 2013

Abstract
Many have attempted to bring the exciting pervasive computing research area into the classroom. Here, we present our experience in organizing and teaching a postgraduate pervasive computing program via distance learning at the Hellenic Open University.
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Dynamic TCP window size adaptation for improving network performance of P2P-aware interactive broadcasting environments

Authors: E. K. Markakis, E. Pallis, C. Skianis, V. Zacharopoulos

Journal: Journal of Communication and Computer

Details: Vol. 9, pp. 1395-1403

Year: 2013

Energy Efficient Network Coding-based MAC for Cooperative ARQ Wireless Networks

Authors: A. Antonopoulos, C. Verikoukis, C. Skianis, O.B. Akan

Journal: Ad Hoc Networks

Details: Vol. 11, pp. 190-200

Year: 2013

Interference versus filtering distortion trade-offs in OFDMbased cognitive radios

Authors: K. Maliatsos, A. Adamis, A. G. Kanatas

Journal: Transactions on Emerging Telecommunications Technologies

Details: Vol. 24, pp. 692-708

Publisher: Wiley

Year: 2013

Introducing Automated Procedures in 3G Network Planning and Optimization Journal of Systems and Software

Authors: C. Skianis

Journal: Journal of Systems and Software

Publisher: Elsevier

Year: 2013

Joint Relay-Pair Selection for Buffer-Aided Successive Opportunistic Relaying

Authors: N. Nomikos, D. Vouyioukas, T. Charalambous, I. Krikidis, P. Makris, D. N. Skoutas, M. Johansson, C. Skianis

Journal: Transactions on Emerging Telecommunications Technologies

Details: Vol. 25, No. 8, pp. 823-834

Publisher: Wiley

Year: 2013

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Network Coding-based Cooperative ARQ Scheme for VANETs

Authors: A. Antonopoulos, C. Skianis, C. Verikoukis

Journal: Journal of Networking and Computer Applications (JNCA)

Details: Vol. 36, No. 3, pp. 1001-1007

Publisher: Elsevier

Year: 2013

Opportunistic TV White Spaces Exploitation through Efficient Radio Resource Management Algorithms in Cognitive Radio Networks

Authors: A. Bourdena, E. Pallis, G. Kormentzas, G. Mastorakis

Journal: Transactions on Emerging Telecommunications Technologies (ETT), High Performance Mobile Opportunistic Systems

Publisher: Wiley

Year: 2013

Optimized Admission Control Scheme for Coexisting Femtocell, Wireless and Wireline Networks

Authors: D. N. Skoutas, P. Makris, C. Skianis

Journal: Telecommunication Systems

Details: Vol. 53, pp. 357–371

Publisher: Springer

Year: 2013

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Performance Analysis of a Two-Hop MIMO Mobile-to-Mobile via Stratospheric-Relay Link Employing Hierarchical Modulation

Authors: N. Nomikos, E. T. Michailidis, D. Vouyioukas, A. G. Kanatas

Journal: International Journal of Antennas and Propagation

Publisher: Hindawi

Year: 2013

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Radio vs Backhaul Bottlenecks: An Integrated QoS Provisioning Approach for Small Cell Gateways

Authors: C. Skianis

Journal: International Journal of Communication Systems

Publisher: Wiley

Year: 2013

Reconfigurable Orthonormal Basis Patterns Using ESPAR Antennas,

Authors: P. Vasileiou, K. Maliatsos, E. Thomatos, A. G. Kanatas

Journal: IEEE Antennas and Wireless Propagation Letters

Details: Vol. 12, pp. 448-451

Publisher: IEEE

Year: 2013

A framework for developing pervasive awareness systems in smart environments

Authors: C. Goumopoulos, A. Kameas, E. Berg

Journal: Int. J. Ad Hoc and Ubiquitous Computing

Details: Vol. 9, No. 3, pp. 142-158

Publisher: Inderscience Publishers

Year: 2012

Abstract
Pervasive Awareness Systems (PASs) collect awareness information from sensors and devices in smart environments and can present it to remote users by using various awareness objects. In this paper, we present a pervasive awareness management framework for supporting the conception, design and realisation of applications that foster social connectedness between communities. The framework consists of
• an awareness model that considers user disturbance and privacy
• a service-oriented platform that provides core awareness services
• assorted tools that support communities to create, adapt and appropriate such applications.
A PAS prototype is presented along with a usability evaluation of the tools.
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A Survey on Context-Aware Mobile and Wireless Networking: On Networking and Computing Environments' Integration

Authors: P. Makris, D. N. Skoutas, C. Skianis

Journal: Communications Surveys & Tutorials, IEEE

Year: 2012

Abstract
During the last years, a continuous convergence and fusion of computing and networking systems is stressed in the ICT research community. Context awareness appears to be a major research "glue-point" of such kind of heterogeneous environments' integration. In this survey paper, we aim to assemble all the "puzzle-pieces" of the emerging research area of Context Aware Mobile and Wireless Networking (CAMoWiN) in order to provide the reader a holistic representation of the work having been done in the past emphasizing in recent research efforts. A precise definition of abstract Context Aware (CA) functionalities together with a clear classification of related state-of-the-art proposals are provided in the form of a proposed taxonomy scheme per CA functionality. Each taxonomy scheme can also serve as a sufficiently general framework permitting the easy classification of novel CAMoWiN solutions emerging in the near future. Therefore, our study not only defines all the possible components of a CAMoWiN architecture and clearly points out the similarities and differences of all research efforts in the field but also evaluates future research trends and paves the way for the researchers to work beyond the concepts investigated in this work. Finally, apart from identifying the open challenges, which arise when applying traditional concepts of pervasive computing to mobile and wireless networks, we further map them to the Mobile Cloud Computing paradigm, whose concepts appear to be very promising regarding next generation networking and computing environments' integration.
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Distributed Point Coordination Function for IEEE 802.11 Wireless Ad hoc Networks

Authors: J. Alonso-Zárate, C. Crespo, C. Skianis, L. Alonso, C. Verikoukis

Journal: Ad Hoc Networks

Details: Vol. 10, No. 3, pp. 536-551

Publisher: Elsevier

Year: 2012

Emerging and adaptive fuzzy logic based behaviours in activity sphere centred ambient ecologies

Authors: C. Wagner, C. Goumopoulos, H. Hagras

Journal: Pervasive and Mobile Computing

Details: Vol. 8, No. 4, pp. 500-521

Publisher: Elsevier Science,

Year: 2012

Abstract
In order for Ambient Ecologies (AEs) to provide a viable and functional service to people in their day-to-day lives, it is paramount for the AEs to autonomously learn and adapt to the requirements of the human users living in their everyday environments which are populated with a large number of potentially heterogeneous artefacts/devices (different manufacturers, different descriptions of properties, etc.). In this paper, we will propose the concept of emerging and adaptive fuzzy logic based behaviours which are based on dynamically created activity spheres. We will provide details both on the conceptual notions behind this approach as well as the detailed results from a real world deployment of our proposed system.
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Symbiotic Ecologies in Next Generation Ambient Intelligent Environments

Authors: H. Hagras, C. Wagner, A. Kameas, C. Goumopoulos, A. Meliones, Y. Bellik, G. Pruvost, T. Heinroth, W. Minker

Journal: International Journal of Next-Generation Computing

Details: Vol. 3, No. 1, pp. 52-86

Publisher: Perpetual Innovation

Year: 2012

Abstract
This paper describes a novel approach to realize symbiotic ecologies within Next Generation Ambient Intelligent Environments (NGAIEs). The proposed approach comprises novel ontology and agent technologies allowing for adaptation on a variety of levels. The metaphor of symbiotic ecologies reflects a meaningful integration of relevant entities (i.e., services, devices, agents) and information within NGAIEs to accomplish a specific user’s task by relying on the symbiotic relationship of the user and his/her intelligent environment. We adopt a service-oriented architecture, combined with (a) intelligent agents that support adaptive task realization and enhanced human-machine interaction and (b) ontologies that provide knowledge representation, management of heterogeneity at user and device level, semantically rich resource discovery and adaptation using ontology alignment mechanisms. In this article, we analyse heterogeneity concerning user behaviour and adaptive user interaction modelling. Furthermore, we focus on heterogeneity regarding the representation of the states of entities and their availability over different networks. The paper will also report on the deployment of a system prototype in a real world setting which is the intelligent flat (iSpace) at the University of Essex.
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Throughput Analysis of a Cooperative ARQ Scheme in the Presence of Hidden and Exposed Terminals

Authors: J. Alonso-Zárate, L. Alonso, G. Kormentzas, R. Tafazolli, C. Verikoukis

Journal: Journal of Mobile Networks and Applications

Details: Vol. 17, No. 2, pp. 258-266

Publisher: Springer

Year: 2012

"Defect-Oriented LFSR Reseeding to Target Unmodeled Defects Using Stuck-at Test Sets"

Authors: X. Kavousianos, V. Tenentes, K. Chakrabarty, E. Kalligeros

Journal: IEEE Transactions on Very Large Scale Integration (VLSI) Systems

Details: Vol. 19, No. 12, pp. 2330-2335

Year: 2011

Abstract
Defect screening is a major challenge for nanoscale CMOS
circuits, especially since many defects cannot be accurately modeled using
known fault models. The effectiveness of test methods for such circuits can
therefore be measured in terms of the coverage obtained for unmodeled
faults. In this paper, we present a new defect-oriented dynamic LFSR reseeding technique for test-data compression. The proposed technique is
based on a new output-deviation metric for grading stuck-at patterns derived from LFSR seeds. We show that, compared to standard compression-driven dynamic LFSR reseeding and a previously proposed deviation-based method, higher defect coverage is obtained using stuck-at test cubes
without any loss of compression.
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A Delay Optimal Scheduling Policy for Real Time Services in WCDMA Systems

Authors: D. Komnakos, D. N. Skoutas, D. Vouyioukas, A. Rouskas

Journal: Wireless Personal Communications

Details: Vol. 61, No. 2, pp. 435-445

Publisher: Springer

Year: 2011

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Enhancing the High Speed Downlink Packet Access Operation of 3G WCDMA Systems

Authors: D. N. Skoutas, C. Skianis

Journal: Wireless Communications and Mobile Computing

Details: Vol. 4, No. 1, pp. 115-127

Publisher: John Wiley & Sons, Ltd.

Year: 2011

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Impact of MIMO Techniques on the Interoperability between UMTS-HSDPA and WLAN Wireless Systems

Authors: K. Peppas, F. Lazarakis, C. Skianis, A. Alexandridis, K. Dangakis

Journal: IEEE Communications Surveys and Tutorials

Details: Vol. 13, No. 4, pp. 708-720

Publisher: Wiley

Year: 2011

Performance Analysis of an Adaptive Algorithm for DOA Estimation

Authors: A. Leros, V. C. Moussas

Journal: IAENG International Journal of Computer Science

Details: Vol. 38, No. 3, pp. 309--313

Year: 2011

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Vertical Handover Framework for Future Collaborative Wireless Networks

Authors: N. Dimitriou, L. Sarakis, D. Loukatos, G. Kormentzas, C. Skianis

Journal: International Journal of Network Management

Details: Vol. 21, No. 6, pp. 548-564

Year: 2011

"Single and Variable-State-Skip LFSRs: Bridging the Gap Between Test Data Compression and Test Set Embedding for IP Cores"

Authors: V. Tenentes, X. Kavousianos, E. Kalligeros

Journal: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

Details: Vol. 29, No. 10, pp. 1640-1644

Year: 2010

Abstract
Even though test set embedding (TSE) methods offer very high compression efficiency, their excessively long test
application times prohibit their use for testing systems-on-chip
(SoC). To alleviate this problem we present two new types
of linear feedback shift registers (LFSRs), the Single-State-Skip
and the Variable-State-Skip LFSRs. Both are normal LFSRs with
the addition of the State-Skip circuit, which is used instead of the
characteristic-polynomial feedback structure for performing successive
jumps of constant and variable length in their state sequence. By
using Single-State-Skip LFSRs for testing single or multiple identical
cores and Variable-State-Skip LFSRs for testing multiple non-identical
cores we get the well-known high compression efficiency of TSE with
substantially reduced test sequences, thus bridging the gap between test
data compression and TSE methods.
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Optimized Fusion of Heterogeneous Wireless Networks based on Media Independent Handover Operations

Authors: G. Lampropoulos, C. Skianis, P. Neves

Journal: IEEE Wireless Communications Magazine

Details: Vol. 17, No. 4, pp. 78-87

Publisher: Wiley

Year: 2010

Throughput Analysis of the Intermittent DCF for Opportunistic Spectrum Access

Authors: A. Adamis, K. Maliatsos, G. Cambourakis, P. Constantinou

Journal: Springer International Journal on Wireless Personal Communications

Details: Vol. 55, pp. 349–377

Publisher: Springer

Year: 2010

Towards Adaptive Security for Convergent Wireless Sensor Networks in Beyond 3G Environments

Authors: A. Mitseva, E. Aivaloglou, A. Marchitti, N. R. Prasad, C. Skianis, S. Gritzalis, A. Waller, T. Bauge, S. Pennington

Journal: Wireless Communications and Mobile Computing

Details: Vol. 10, No. 9, pp. 1193-1207

Publisher: Wiley Inderscience

Year: 2010

Abstract
The integration of wireless sensor networks with different network systems gives rise to many research challenges to ensure security, privacy and trust in the overall architecture. The main contribution of this paper is a generic security, privacy and trust framework providing context-aware adaptability, flexibility and scalability which allows customisation of wireless sensor networks to a diverse set of application spaces. Suitable protocols and mechanisms are identified, which when combined according to the framework form a complete toolbox solution which fits the architecture of Beyond 3G environments. Performance evaluation results demonstrate the feasibility and estimate the benefits of the security framework for a variety of scenarios.
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A DVB/IP QoS aware Backhaul Networking Environment

Authors: G. Mastorakis, E. Pallis, G. Kormentzas

Journal: Wireless Personal Communications

Year: 2009

A Scheduling Algorithm with Dynamic Priority Assignment for WCDMA Systems

Authors: D. N. Skoutas, A. Rouskas

Journal: IEEE Transactions on Mobile Computing

Details: Vol. 8, No. 1, pp. 126-138

Publisher: https://doi.org/10.1109/TMC.2008.106

Year: 2009

Ambient ecologies in smart homes

Authors: C. Goumopoulos, A. Kameas

Journal: The Computer Journal

Details: Vol. 52, No. 8, pp. 922-937

Publisher: Oxford University Press

Year: 2009

Abstract
An important characteristic of ubiquitous computing (UbiComp) environments is the integration of information, communication and sensing technologies into our everyday objects, giving rise to a new proactive computing model in homes. A smart home uses networked sensors, devices and appliances to build an intelligent environment in which many activities in the home are automated and where devices and services seamlessly cooperate to support domestic tasks. Programming and maintaining such an infrastructure is challenging because suitable abstractions are currently missing. In this work we have attempted to define ambient ecologies as a metaphor for modeling UbiComp applications, specify design patterns and programming principles and develop infrastructure to provide a paradigm of application engineering and tools to support ambient ecology designers, developers and end-users. We describe our model and the middleware architecture and present the engineering of applications in a smart home environment.
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An ontology-driven system architecture for precision agriculture applications

Authors: C. Goumopoulos, A. Kameas, A. Cassells

Journal: International Journal of Metadata, Semantics and Ontologies

Details: Vol. 4, No. 1-2, pp. 72-84

Publisher: Inderscience Publishers

Year: 2009

Abstract
Our research has been performed in the context of the EU-funded R&D project PLANTS. In this paper, we describe an ontology-driven architecture for developing systems that can be used in precision agriculture applications. Central to our approach is the use of an ontology, which views plants and associated computation as an integral part and allows the interaction of plants and artefacts in the form of synergistic mixed societies. PLANTS ontology sets up a conceptual framework that combines the knowledge about sensors, actuators and other domain concepts available, on the one hand, and the biological studies about plant stressing and sensing mechanisms and consequent plant behaviour, on the other hand, to make plants a proactive component of agricultural systems.
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Analysis and Modeling of H.264 Unconstrained VBR Video Traffic

Authors: H. Koumaras, C. Skianis, A. Kourtis

Journal: International Journal of Mobile Computing and Multimedia Communications (IJMCMC)

Details: Vol. 1, No. 4, pp. 4-31

Publisher: IGI-Global

Year: 2009

Ontology-based modeling of dynamic ubiquitous computing applications as evolving activity spheres

Authors: L. Seremeti, C. Goumopoulos, A. Kameas

Journal: Pervasive and Mobile Computing

Details: Vol. 5, No. 5, pp. 574-591

Publisher: Elsevier Science

Year: 2009

Abstract
As the computer disappears in the environments surrounding our activities, the objects therein become augmented with sensors, actuators, processors, memories, wireless communication modules and they can receive, store, process and transmit information. In addition to objects, spaces also undergo a change towards becoming smart and eventually Ambient Intelligence (AmI) spaces. In order to model the way everyday activities are carried out within an AmI environment, we introduce the notion of ‘‘activity sphere’’. In this paper, we are interested in the ontology-based representation of activity spheres from two different perspectives (as creators and as observers), as well as the modeling and control of the dynamic nature of activity spheres.
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Smart objects as components of UbiComp applications

Authors: C. Goumopoulos, A. Kameas

Journal: International Journal of Multimedia and Ubiquitous Engineering

Details: Vol. 4, No. 3, pp. 1-20

Publisher: SERSC Press

Year: 2009

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Throughput and Packet Delay Analysis of the Intermittent DCF for Overlay Access Networks

Authors: A. Adamis, K. Maliatsos, P. Constantinou

Journal: IEICE Transactions On Communications

Details: Vol. E92-B, No. 11

Year: 2009

Wavelet-based Compression with ROI Coding Support for Mobile Access to DICOM Images over Heterogeneous Radio Networks

Authors: I. Maglogiannis, C. Doukas, G. Kormentzas, T. Pliakas

Journal: IEEE Transactions on Information Technology in Biomedicine

Publisher: IEEE

Year: 2009

"An Efficient Spatial Domain Technique for Subpixel Image Registration"

Authors: I. G. Karybali, E. Z. Psarakis, K. Berberidis , G. D. Evangelidis

Journal: Signal Processing: Image Communication

Details: Vol. 23, pp. 711-724

Publisher: Elsevier

Year: 2008

Abstract
In this paper a new technique for performing image registration with subpixel accuracy
is presented. The proposed technique, which is based on the maximization of the
correlation coefficient function, does not require the reconstruction of the intensity
values and provides a closed-form solution to the subpixel translation estimation
problem. Moreover, an efficient iterative scheme is proposed, which reduces
considerably the overall computational cost of the image registration problem. This
scheme properly combined with the proposed similarity measure results in a fast spatial
domain technique for subpixel image registration.
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"Multilevel Huffman Test-Data Compression for IP Cores with Multiple Scan Chains"

Authors: X. Kavousianos, E. Kalligeros, D. Nikolos

Journal: IEEE Transactions on Very Large Scale Integration (VLSI) Systems

Details: Vol. 16, No. 7, pp. 926-931

Year: 2008

Abstract
Various compression methods have been proposed for tackling
the problem of increasing test-data volume of contemporary, core-based
systems. Despite their effectiveness, most of the approaches that are based
on classical codes (e.g., run-lengths, Huffman) cannot exploit the test-application-time advantage of multiple-scan-chain cores, since they are not
able to perform parallel decompression of the encoded data. In this paper,
we take advantage of the inherent parallelism of Huffman decoding and
we present a generalized multilevel Huffman-based compression approach
that is suitable for cores with multiple scan chains. The size of the encoded
data blocks is independent of the slice size (i.e., the number of scan chains),
and thus it can be adjusted so as to maximize the compression ratio. At the
same time, the parallel data-block decoding ensures the exploitation of most
of the scan chains’ parallelism. The proposed decompression architecture
can be easily modified to suit any Huffman-based compression scheme.
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"Test Data Compression Based on Variable-to-Variable Huffman Encoding with Codeword Reusability"

Authors: X. Kavousianos, E. Kalligeros, D. Nikolos

Journal: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

Details: Vol. 27, No. 7, pp. 1333-1338

Year: 2008

Abstract
A new statistical test data compression method that is suitable
for IP cores of an unknown structure with multiple scan chains is proposed
in this paper. Huffman, which is a well-known fixed-to-variable code, is
used in this paper as a variable-to-variable code. The precomputed test
set of a core is partitioned into variable-length blocks, which are, then,
compressed by an efficient Huffman-based encoding procedure with a
limited number of codewords. To increase the compression ratio, the same
codeword can be reused for encoding compatible blocks of different sizes.
Further compression improvements can be achieved by using two very
simple test set transformations. A simple and low-overhead decompression
architecture is also proposed.
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A Guard Code Scheme for Handover Traffic Management in WCDMA Systems

Authors: D. N. Skoutas, Saied M. Abd El-atty, A. Rouskas

Journal: International Journal of Wireless Information Networks

Details: Vol. 15, No. 2, pp. 98-104

Publisher: Springer

Year: 2008

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Broadband Multimedia on the move with DVB-H

Authors: G. Gardikis, G. Xilouris, C. Skianis, T. Kourtis

Journal: Multimedia Tools and Applications

Details: Vol. 36, No. 1-2, pp. 133-144

Publisher: Springer

Year: 2008

Dynamic IP Configuration of Terminals in Broadcasting Networks

Authors: G. Gardikis, S. Orfanos, G. Kormentzas, E. Pallis, A. Kouris

Journal: Computer Networks

Details: Vol. 52, pp. 292–302

Year: 2008

End-to-end QoS issues of MPEG-4 FGS video streaming traffic delivery in an IP/DVB/UMTS network

Authors: T. Pliakas, G. Kormentzas, C. Skianis

Journal: European Journal of Operational Research

Details: Vol. 191, pp. 1089-1100

Publisher: Elsevier

Year: 2008

Reducing CQI Signalling Overhead in HSPA

Authors: Saied M. Abd El-atty, D. N. Skoutas, A. Rouskas

Journal: Research Letters in Communications

Details: Vol. 2008

Year: 2008

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Saturation Throughput Analysis of a Cluster-based Medium Access Control Protocol for Single-hop Ad Hoc Wireless Networks

Authors: J. Alonso-Zárate, E. Kartsakli, C. Skianis, C. Verikoukis, L. Alonso

Journal: Simulation: Transactions of the Society for Modeling and Simulation International

Details: Vol. 84, No. 12, pp. 619-633

Year: 2008

Trust Establishment in Sensor Networks: Behavior-based, Certificate-based, and a Combinational Approach

Authors: E. Aivaloglou, S. Gritzalis, C. Skianis

Journal: International Journal of System of Systems Engineering

Details: Vol. 1, No. 1-2, pp. 128-148

Publisher: Inderscience Publisher

Year: 2008

Abstract
Sensor networks highly depend on the distributed cooperation among network nodes. Trust establishment frameworks provide the means for representing, evaluating, maintaining and distributing trust within the network, and serve as the basis for higher level security services. This paper provides a state-of-the art review of trust establishment frameworks for ad hoc and sensor networks. Certain types of frameworks are identified, such as behaviour-based and certificate-based, according to their scope, purpose and admissible types of evidence. The review is complemented by a comparative study built both on criteria specific to each category and on common criteria, grouped into three distinct classes: supported trust characteristics, complexity and requirements and deployment complexity and flexibility. We then present a trust establishment framework targeted for sensor networks that combines aspects from the two alternative approaches on trust establishment on common evaluation metrics, so that it can uniformly support the needs of nodes with highly diverse network roles and capabilities.
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"Multilevel Huffman Coding: An Efficient Test-Data Compression Method for IP Cores"

Authors: X. Kavousianos, E. Kalligeros, D. Nikolos

Journal: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

Details: Vol. 26, No. 6, pp. 1070-1083

Year: 2007

Abstract
A new test-data compression method suitable for
cores of unknown structure is introduced in this paper. The proposed method encodes the test data provided by the core vendor
using a new, very effective compression scheme based on multilevel
Huffman coding. Each Huffman codeword corresponds to three
different kinds of information, and thus, significant compression
improvements compared to the already known techniques are
achieved. A simple architecture is proposed for decoding the
compressed data on chip. Its hardware overhead is very low and
comparable to that of the most efficient methods in the literature.
Moreover, the major part of the decompressor can be shared
among different cores, which reduces the hardware overhead of
the proposed architecture considerably. Additionally, the proposed
technique offers increased probability of detection of unmodeled
faults since the majority of the unknown values of the test sets are
replaced by pseudorandom data generated by a linear feedback
shift register.
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"Optimal Selective Huffman Coding for Test-Data Compression"

Authors: X. Kavousianos, E. Kalligeros, D. Nikolos

Journal: IEEE Transactions on Computers

Details: Vol. 56, No. 8, pp. 1146-1152

Year: 2007

Abstract
Selective Huffman coding has recently been proposed for efficient test-
data compression with low hardware overhead. In this paper, we show that the
already proposed encoding scheme is not optimal and we present a new one,
proving that it is optimal. Moreover, we compare the two encodings theoretically
and we derive a set of conditions which show that, in practical cases, the proposed
encoding always offers better compression. In terms of hardware overhead, the
new scheme is at least as low-demanding as the old one. The increased
compression efficiency, the resulting test-time savings, and the low hardware
overhead of the proposed method are also verified experimentally.
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A conceptual model and the supporting middleware for composing ubiquitous computing applications

Authors: N. Drossos, C. Goumopoulos, A. Kameas

Journal: Journal of Ubiquitous Computing and Intelligence

Details: Vol. 1, No. 2, pp. 174-186

Publisher: American Scientific Publishers

Year: 2007

Abstract
Given the resulting complexity of the ambient applications that one can form in the Ubiquitous or Pervasive Computing domain it is required to abstract the intricacies of a heterogeneous supporting environment (e.g., intrinsic characteristics of specific communication models) away from the application logic. These applications will be characterized by the increasing ubiquity of interactions between many possibly heterogeneous artifacts and services. This paper presents the Plug/Synapse abstraction, which provides a conceptual model for building ubiquitous computing applications in a high-level programming manner. GAS-OS is the software layer that implements the Plug/Synapse model and the concepts encapsulated in GAS, a generic architectural style, which can be used to describe everyday environments populated with computational artifacts. The paper examines also the design and architecture of GAS-OS, which is the minimum set of modules and functionalities that every device must afford, in order to be a ubiquitous computing artifact and participate in artifact collections.
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A Cross Layer Scheduling Framework for Supporting Bursty Data Applications in WCDMA Networks

Authors: Saied M. Abd El-atty, D. N. Skoutas, A. Rouskas, G. T. Karetsos

Journal: Wireless Personal Communications

Publisher: Springer

Year: 2007

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A Fusion IP/DVB Networking Environment for Providing Always-On Connectivity and Triple-Play Services to Urban and Rural Areas

Authors: G. Mastorakis, E. Pallis, G. Kormentzas

Journal: IEEE Networks

Details: Vol. 21, No. 2, pp. 21-27

Year: 2007

A Fuzzy Logic-based AQM for Real-time Traffic over Internet

Authors: Y. H. Aoul, A. Mehaoua, C. Skianis

Journal: Computer Networks

Details: Vol. 51, No. 16, pp. 4617-4633

Publisher: Elsevier Science

Year: 2007

Admission control algorithm for aggregated pipes service invocation in multi-domain IP environment

Authors: E. Borcoci, G. Kormentzas, A. Asgari, T. Ahmed

Journal: Computer Networks

Details: Vol. 51, pp. 4669–4678

Year: 2007

Efficiency Study of the Information Flow Mechanism Enabling Interworking of Heterogeneous Wireless Systems

Authors: C. Skianis, G. Kormentzas, K. Kontovasilis, G. Lisa

Journal: The Journal of Systems and Software

Details: Vol. 80, pp. 1746–1753

Publisher: Elsevier Science

Year: 2007

Performance Analysis of IEEE 802.11 Ad Hoc Networks in the Presence of Exposed Terminals

Authors: D. Vassis, G. Kormentzas

Journal: Ad Hoc Networks

Year: 2007

Scalable Video Streaming Traffic Delivery in IP/UMTS Networking Environments

Authors: T. Pliakas, G. Kormentzas, C. Skianis

Journal: Journal of Multimedia

Details: Vol. 2, No. 2, pp. 37-46

Publisher: Academy Publisher

Year: 2007

Service Management Enhancements to IMS Architecture

Authors: G. Kormentzas, T. Andrade, H. Asgari, C. Skianis

Journal: International Journal of Network Management

Details: Vol. 17, pp. 363-371

Publisher: Wiley

Year: 2007

Towards a flexible trust establishment framework for sensor networks

Authors: E. Aivaloglou, S. Gritzalis, C. Skianis

Journal: Telecommunication Systems: Modelling, Analysis, Design and Management

Details: Vol. 35, No. 3-4, pp. 207-213

Publisher: Springer

Year: 2007

Abstract
Wireless sensor networks highly depend on the distributed cooperation among network nodes. Trust establishment frameworks provide the means for representing, evaluating, maintaining and distributing trust within the network, and serve as the basis for higher level security services. In this paper, we propose a trust establishment framework targeted sensor networks that can uniformly support the needs of nodes with highly diverse network roles and capabilities, by exploiting the pre-deployment knowledge on the network topology and the information flows. The framework allows for flexibility by combining aspects from alternative approaches on trust establishment on common evaluation metrics, and enables controlled trust evolution based on the network pre-configuration.
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UbiXML: Programmable Management of Ubiquitous Computing Resources

Authors: D. Alexopoulos, J. Soldatos, G. Kormentzas, C. Skianis

Journal: International Journal of Network Management

Details: Vol. 17, No. 6, pp. 415-435

Publisher: Wiley

Year: 2007

’Performance Analysis of IEEE 802.11 Ad Hoc Networks in the Presence of Hidden Terminals

Authors: D. Vassis, G. Kormentzas

Journal: Computer Networks

Details: Vol. 51, pp. 2345–2352

Year: 2007

"Efficient Spatial Image Watermarking via New Perceptual Masking and Blind Detection Schemes"

Authors: I. G. Karybali, K. Berberidis

Journal: IEEE Transactions on Information Forensics and Security

Details: Vol. 1, No. 2, pp. 256-274

Year: 2006

Abstract
The aim of this paper is to improve the performance of spatial domain watermarking. To this end, a new perceptual mask and a new detection scheme are proposed. The proposed spatial perceptual mask is based on the cover image prediction error sequence and matches very well with the properties of the human visual system. It exhibits superior performance compared to existing spatial masking schemes. Moreover, it allows for a significantly increased strength of the watermark while, at the same time, the watermark visibility is decreased. The new blind detection scheme comprises an efficient prewhitening process and a correlation-based detector. The prewhitening process is based on the
least-squares prediction error filter and substantially improves the detector’s performance. The correlation-based detector that was selected is shown to be the most suitable for the problem at hand. The improved performance of the proposed detection scheme has been justified theoretically for the case of linear filtering plus noise attack and through extensive simulations. The theoretical analysis is independent of the proposed mask and the derived expressions can be used for any watermarking technique based on spatial masking. It is shown though that in most cases the detector performs
better if the proposed mask is employed.
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End-to-End Quality of Service Provisioning Through an Integrated Management System for Multimedia Content Delivery

Authors: T. Ahmed, A. Asgari, A. Mehaoua, E. Borcoci, L. Berti-Équille, G. Kormentzas

Journal: Computer Communications

Year: 2006

Exploiting Digital Switchover for Broadband Services Access in Rural Areas

Authors: G. Mastorakis, E. Pallis, C. Mantakas, G. Kormentzas, C. Skianis

Journal: Journal of Communications

Details: Vol. 6, No. 1, pp. 45-50

Publisher: Academy Publisher

Year: 2006

Joint order and parameter estimation of multivariate autoregressive models using multi-model partitioning theory

Authors: S. Pappas, A. Leros, S. K. Katsikas

Journal: Digital Signal Processing

Details: Vol. 16, No. 6, pp. 782-795

Publisher: Elsevier

Year: 2006

Performance Evaluation of Single and Multi-Channel Actor to Actor Communication for Wireless Sensor Actor Networks

Authors: D. Vassis, G. Kormentzas, C. Skianis

Journal: Ad Hoc Networks

Details: Vol. 4, No. 4, pp. 487-498

Publisher: Elsevier Science

Year: 2006

Service-driven Inter-domain QoS Monitoring System for Large-scale IP and DVB Networks

Authors: A. Mehaoua, T. Ahmed, H. Asgari, M. Sidibe, A. Nafaa, G. Kormentzas, T. Kourtis, C. Skianis

Journal: Computer Communications

Details: Vol. 29, No. 10, pp. 1687-1695

Publisher: Elsevier Science

Year: 2006

The Wisconsin Breast Cancer Problem: Diagnosis and TTR/DFS time prognosis using probabilistic and generalised regression information classifiers

Authors: J. Anagnostopoulos, C. Anagnostopoulos, D. Vergados, A. Rouskas, G. Kormentzas

Journal: Oncology Reports, special issue Computational Analysis and Decision Support Systems in Oncology

Details: Vol. 15, pp. 975-982

Year: 2006

Traffic Shaping based on an Exponential Token Bucket for Quantitative QoS: Implementation and Experiments on DiffServ Routers

Authors: E. Vayias, J. Soldatos, G. Kormentzas

Journal: Computer Communications

Details: Vol. 29, pp. 781–797

Year: 2006

Delay Performance Analysis and Evaluation of IEEE 802.11e EDCA in Finite Load Conditions

Authors: D. Vassis, G. Kormentzas

Journal: Wireless Personal Communications

Details: Vol. 34, pp. 29–43

Year: 2005

Interactions between Intelligent Multimodal Terminals and a Network Management System in a B3G Context

Authors: C. Skianis, G. Kormentzas, K. Kontovasilis

Journal: Wireless Communications & Mobile Computing

Details: Vol. 5, pp. 679-695

Publisher: Wiley

Year: 2005

Management of Channelization Codes at the Forward Link of WCDMA

Authors: A. Rouskas, D. N. Skoutas

Journal: IEEE Communication Letters

Details: Vol. 9, No. 8, pp. 679 - 681

Publisher: IEEE

Year: 2005

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On the Building Blocks of Quality of Service in Heterogeneous IP Networks

Authors: J. Soldatos, E. Vayias, G. Kormentzas

Journal: IEEE Communications Surveys and Tutorials

Details: Vol. 7, No. 1, pp. 70-89

Year: 2005

On the Effectiveness of DVB-T for the Support of IP-based Services in Heterogeneous Wireless Networks

Authors: D. Kouis, D. Loukatos, K. Kontovasilis, G. Kormentzas, C. Skianis

Journal: Computer Networks

Details: Vol. 48, No. 1, pp. 57-73

Publisher: Elsevier Science

Year: 2005

The IEEE 802.11g Standard for High Data Rate WLANs

Authors: D. Vassis, G. Kormentzas, A. Rouskas, I. Maglogiannis

Journal: IEEE Network Magazine

Year: 2005

WPAN’s Technologies for Pervasive e-Health Applications – State of the Art and Future Trends

Authors: D. Vouyioukas, I. Maglogiannis, D. Vergados, G. Kormentzas, A. Rouskas

Journal: Journal for Quality of Life Research

Details: Vol. 3, No. 2, pp. 198-204

Year: 2005

"Multiphase BIST: A New Reseeding Technique for High Test Data Compression"

Authors: E. Kalligeros, X. Kavousianos, D. Nikolos

Journal: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

Details: Vol. 23, No. 10, pp. 1429-1446

Year: 2004

Abstract
In this paper, a new reseeding architecture for scan-based built-in self-test (BIST), which uses a linear feedback shift
register (LFSR) as test pattern generator, is proposed. Multiple
cells of the LFSR are utilized as sources for feeding the scan chain
of the circuit under test in different test phases. The LFSR generates the same state sequence in all phases, keeping that way the implementation cost low. A seed-selection algorithm is furthermore
presented that, taking advantage of the multiphase architecture,
manages to significantly reduce the number of the required seeds
for achieving complete (100%) fault coverage. The proposed technique can be used either in a full BIST implementation or in a
test-resource partitioning scenario, since the test-data storage requirements on the tester are very low. When a full BIST implementation is preferable, the multiphase architecture can also be
combined with a dynamic reseeding scheme that uses combinational logic instead of a ROM in order to perform the reseedings.
This way the implementation area of the BIST circuitry is further
reduced. Experimental results demonstrate the advantages of the
proposed LFSR reseeding approach over the already known reseeding techniques.
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A Modeling and Simulation Framework for Compound Medical Applications in Regional Healthcare Networks

Authors: G. Kormentzas, I. Maglogiannis, D. Vassis, D. Vergados, A. Rouskas

Journal: International Journal of Electronic Healthcare (IJEH)

Publisher: InderScience Publishers

Year: 2004

Advanced SSL/TLS based Authentication for Secure WLAN-3G Interworking

Authors: G. Kambourakis, A. Rouskas, G. Kormentzas, S. Gritzalis

Journal: IEE Proceedings Communications

Details: Vol. 151, No. 5, pp. 501-506

Publisher: IEE Press

Year: 2004

Abstract
Motivated by the fact that the SSL protocol has proved its effectiveness in wired IP networks, recent research work has examined the potential use of this protocol in various wireless technologies. Although Wi-Fi networks present security deficiencies, they manage to penetrate the wireless market to a great degree due to their low cost, easy administration, great capacity, IP-oriented nature, etc. Considering Wi-Fi networking settings, administrated by different operators, as parts of a common core 3G infrastructure, the author propose the potential application of enhanced SSL-based authentication mechanisms in integrated emerging-3G and Wi-Fi networks. Existing problems related to authentication and key agreement (AKA) procedures and the extensible authentication protocol (EAP)-AKA, as they appear in the latest 3G and integrated 3G/ Wi-Fi specifications, are discussed. It is proposed how EAP-TLS, combined with public key infrastructure (PKI) elements, can be used to overcome these inefficiencies in a hybrid WLAN 3G heterogeneous environment, in order to provide strong authentication and end-to-end security to the mobile user.
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Code Reservation Schemes at the Forward Link in WCDMA

Authors: A. Rouskas, D. N. Skoutas, G. Kormentzas, D. Vergados

Journal: Elsevier Computer Communications

Details: Vol. 27, No. 9, pp. 792-800

Year: 2004

Efficient trip generation with a rule modeling system for crew scheduling problems

Authors: C. Goumopoulos, E. Housos

Journal: Journal of Systems and Software

Details: Vol. 69, No. 1-2, pp. 43-56

Publisher: Elsevier Science

Year: 2004

Abstract
Trip generation is the most time consuming phase in the solution process of crew scheduling problems faced by large transportation companies such as airlines and railways. A large number of trips must be constructed while satisfying a complex set of regulations. In this paper, we present an efficient trip generation method that utilizes originally a rule modeling system in order to reduce the corresponding search space. Special pruning rules are defined using a high-level rule language, which also supports the modeling of the business regulations required in the scheduling process. In addition, the legality checking mechanism involved has been tuned to perform efficiently in order to cope with the vast amount of the legality checks required by the trip generator. The algorithms are tested as a module for a crew scheduling application satisfying the tight response time requirements of a production system. We present experimental results based on problems provided by a major European airline that validate the usefulness and applicability of our work.
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Emerging Web-Services for Ship Travelers

Authors: I. Maglogiannis, G. Kormentzas, N. Panagiotarakis

Journal: Information Technology and Tourism (ITT)

Details: Vol. 7, No. 1, pp. 23-31

Year: 2004

A Web-based Database System for Providing Technical Information on ATM Networking Platforms

Authors: K. Kontovasilis, G. Kormentzas, A. Kourtis, N. Mitrou, J. Soldatos, E. Vayias

Journal: Journal of Computing and Information Technology

Details: Vol. 11, No. 1, pp. 1-13

Year: 2003

Measurement and Statistical Analysis of Asymmetric Multipoint Videoconference Traffic in IP Networks

Authors: C. Skianis, K. Kontovasilis, A. Drigas, M. Moatsos

Journal: Telecommunication Systems Modeling, Analysis, Design and Management

Details: Vol. 23, No. 1-2, pp. 95-122

Publisher: Kluwer Academic Press

Year: 2003

"On the design of low power BIST for multipliers with Booth encoding and Wallace tree summation"

Authors: D. Bakalis , E. Kalligeros, D. Nikolos, H. T. Vergos , G. Alexiou

Journal: Journal of Systems Architecture

Details: Vol. 48, No. 4-5, pp. 125-135

Publisher: Elsevier

Year: 2002

Abstract
Low power dissipation (PD) during testing is emerging as one of the major objectives of a built-in self-test (BIST)
designer. In this paper we examine the testability of multipliers based on Booth encoding and Wallace tree summation
of the partial products and we present a methodology for deriving a low power BIST scheme for them. We propose
several design rules for designing the Wallace tree in order to be fully testable under the cell fault model. The proposed
low power BIST scheme for the derived multipliers is achieved by: (a) introducing suitable test pattern generators
(TPGs), (b) properly assigning the TPG outputs to the multiplier inputs and (c) significantly reducing the test set length.
Results indicate that the total power dissipated, the average power per test vector and the peak PD during testing can be
reduced up to 73%, 27% and 36% respectively with respect to earlier schemes, depending on the implementation of the
basic cells and the size of the multiplier. The test application time is also significantly reduced, while the introduced
BIST scheme implementation area is small.
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"On-the-fly Reseeding: A New Reseeding Technique for test-per-clock BIST"

Authors: E. Kalligeros, X. Kavousianos, D. Bakalis , D. Nikolos

Journal: Journal of Electronic Testing: Theory and Applications

Details: Vol. 18, No. 3, pp. 315-332

Publisher: Kluwer Academic Publishers (Springer)

Year: 2002

Abstract
In this paper we present a new reseeding technique for test-per-clock test pattern generation suitable
for at-speed testing of circuits with random-pattern resistant faults. Our technique eliminates the need of a ROM
for storing the seeds since the reseeding is performed on-the-fly by inverting the logic value of some of the bits of
the next state of the Test Pattern Generator (TPG). The proposed reseeding technique is generic and can be applied
to TPGs based on both Linear Feedback Shift Registers (LFSRs) and accumulators. An efficient algorithm for
selecting reseeding points is also presented, which targets complete fault coverage and allows to well exploiting
the trade-off between hardware overhead and test length. Using experimental results we show that the proposed
method compares favorably to the other already known techniques with respect to test length and the hardware
implementation cost.
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A Framework for Designing ATM Network Management Systems by way of Abstract Information Models and Distributed Object Architectures

Authors: K. Kontovasilis, G. Kormentzas, N. Mitrou, J. Soldatos, E. Vayias

Journal: Computer Communications

Details: Vol. 24, No. 7-8, pp. 641-653

Year: 2001

An Open Architecture for Transparently Embedding Advanced Traffic Control Functionality in ATM Switches

Authors: G. Kormentzas, K. Kontovasilis

Journal: Journal of Communications and Networks (JCN)

Details: Vol. 3, No. 1, pp. 64-77

Year: 2001

A Broadband Wireless Access System for Wired and Wireless LANs

Authors: G. Kormentzas, E. Pallis, A. Kourtis, K. Kontovasilis

Journal: Journal of Communications and Networks (JCN)

Details: Vol. 2, No. 3, pp. 259-265

Year: 2000

Arbitrary Open Queueing Networks with Server Vacation Periods and Blocking

Authors: C. Skianis, D. D. Kouvatsos

Journal: Annals of Operations Research

Details: Vol. 79, pp. 143-180

Publisher: Springer Netherlands

Year: 1998

Towed array shape estimation using multimodel partitioning filters

Authors: N. Nikitakos, A. Leros, S. K. Katsikas

Journal: IEEE Journal of Oceanic Engineering

Details: Vol. 23, No. 4, pp. 380-384

Year: 1998

Rule handling in the day-to-day resource management problem: an object-oriented approach

Authors: K. Thrampoulidis, C. Goumopoulos, E. Housos

Journal: Information and Software Technology Journal

Details: Vol. 39, No. 3, pp. 185-193

Publisher: Elsevier Science

Year: 1997

Abstract
The day-to-day resource management problem is caused by a set of unexpected events which disturb the planned daily activities and thus change the long-term optimal schedule. The solution to this problem presupposes that all the regulations for the handling of resources in the particular application domain have been satisfied. In this paper, a new approach to handling the rules in the resource management problem is presented. An object-oriented application specific language that allows the flexible expression of the rules, as well as the corresponding rule handling subsystem are presented. The design of the whole system is based on a generic meta-model derived from the object-oriented paradigm. This makes the system applicable to a wide range of problem domains such as repairs management, airline and other transportation scheduling, school scheduling, etc. The system has been developed and tested as a subsystem of the DAYSY system, a day-to-day resource management system for the airline domain.
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Underwater tracking of a maneuvering target using time delay measurements

Authors: S. K. Katsikas, A. Leros, D. G. Lainiotis

Journal: Signal Processing

Details: Vol. 41, No. 1, pp. 17-29

Publisher: Elsevier

Year: 1995

Passive tracking of a maneuvering target: An adaptive approach

Authors: S. K. Katsikas, A. Leros, D. G. Lainiotis

Journal: IEEE Transactions on Signal Processing

Details: Vol. 42, No. 7, pp. 1820-1825

Year: 1994

Vulnerability Assessment of Cybersecurity for IoT Environments

Authors: Y. Nikoloudakis, G. Mastorakis, E. Pallis, E. Markakis, C. Skianis, G. Kormentzas

Journal: Submmited in IEEE Wireless Communications Magazine

Year: 1979