The integration of Unmanned Aerial Vehicles (UAVs) and Low-Earth Orbit (LEO) satellites as aerial nodes in non-terrestrial networks (NTNs) presents both opportunities and challenges for on-demand 6G interconnectivity. This paper presents a new Composite Cost Metric (CCM) which improves energy-efficient routing performance in combined UAV-satellite constellations. We consider incorporating cumulative Free Space Path Loss (FSPL) and residual energy into the route selection process for both proactive and reactive protocols, our approach refines the routing decisions of classical protocols. The proposed CCM-driven modifications and protocol-specific integration typologies can improve overall route stability, reduce energy consumption per delivered packet, and optimize network reliability by dynamically selecting relays with lower attenuation and higher energy availability. We develop an NS-3-based simulation framework that integrates realistic satellite orbital mechanics, UAV mobility models, and a hybrid energy model that includes solar energy harvesting for satellites. Simulation results demonstrate that our enhancements can indeed outperform baseline implementations in packet delivery ratio, energy efficiency, and end-to-end delay which makes them viable for next-generation NTN-supported 6G networks, at the expense of some additional control overhead. With this set of developments we aim to pave the way for global-optimum and energy-aware emergency and disaster relief communications.

Malware detection is increasingly challenged by evolving techniques like obfuscation and polymorphism, limiting the effectiveness of traditional methods. Meanwhile, the widespread adoption of software containers has introduced new security challenges, including the growing threat of malicious software injection, where a container, once compromised, can serve as entry point for further cyberattacks. In this work, we address these security issues by introducing a method to identify compromised containers through machine learning analysis of their file systems. We cast the entire software containers into large RGB images via their tarball representations, and propose to use established Convolutional Neural Network architectures on a streaming, patchbased manner. To support our experiments, we release the COSOCO dataset-the first of its kind-containing 3364 largescale RGB images of benign and compromised software containers at https://huggingface.co/datasets/k3ylabs/cosoco-imagedataset. Our method detects more malware and achieves higher F1 and Recall scores than all individual and ensembles of VirusTotal engines, demonstrating its effectiveness and setting a new standard for identifying malware-compromised software containers.

Federated learning (FL) enables devices to collaboratively build a shared machine learning (ML) or deep learning (DL) model without exposing raw data. Its privacy-preserving nature has made it popular for intrusion detection systems (IDS) in the field of cybersecurity. However, data heterogeneity across participants poses challenges for FL-based IDS. This paper proposes statistical averaging (StatAvg) method to alleviate non-independently and identically (non-iid) distributed features across local clients’ data in FL. In particular, StatAvg allows the FL clients to share their individual local data statistics with the server. These statistics include the mean and variance of each client’s feature vector. The server then aggregates this information to produce global statistics, which are shared with the clients and used for universal data normalization, i.e., common scaling of the input features by all clients. It is worth mentioning that StatAvg can seamlessly integrate with any FL aggregation strategy, as it occurs before the actual FL training process. The proposed method is evaluated against well-known baseline approaches that rely on batch and layer normalization, such as FedBN, and address the non-iid features issue in FL. Experiments were conducted using the TON-IoT and CIC-IoT-2023 datasets, which are relevant to the design of host and network IDS, respectively. The experimental results demonstrate the efficiency of StatAvg in mitigating non-iid feature distributions across the FL clients compared to the baseline methods, offering a gain in IDS accuracy ranging from 4% to 17%.

With the ongoing integration of machine learning models into critical infrastructure, the resilience of these systems against adversarial attacks is important for all domains. This paper introduces an adversarial attack generator framework against a network dataset that is part of OCPP Dataset using CI-CFlowMeter parser. We conduct a comprehensive evaluation of various prominent adversarial attacks, including FGSMA, JSMA, PGD, C&W, and more to assess their efficacy on the OCCP dataset. The Adversarial Generator is meticulously evaluated, demonstrating a significant impact in the models performance to detect potential perturbations. The results showcased the impact of the different type of adversarial attacks, contributing to a critical advancement in future defense strategies that need to be utilised in order to protect industrial control systems.

This work was motivated by the need to enable teaching educational robotics and other STEM topics in online and blended modes supported by digital tools. This need has been highlighted by the outbreak of the covid-19 pandemic. This paper presents the research findings and outcomes of a systematic effort to design, implement, and demonstrate the feasibility of preparing, creating, and applying enhanced digital educational material for educational robotics activities using augmented reality technology. The integration of augmented reality with educational robotics was identified through the Group Concept Mapping methodology, and the feedback obtained was utilized to develop a co-design instructional methodology. To demonstrate this approach a universal framework is proposed, accompanied by two augmented reality implementations employing reusable digital assets.

The electrical grid has significantly evolved over the years, thus creating a smart paradigm, which is well known as the smart electrical grid. However, this evolution creates critical cybersecurity risks due to the vulnerable nature of the industrial systems and the involvement of new technologies. Therefore, in this paper, the ELECTRON architecture is presented as an integrated platform to detect, mitigate and prevent potential cyberthreats timely. ELECTRON combines both cybersecurity and energy defence mechanisms in a collaborative way. The key aspects of ELECTRON are (a) dynamic risk assessment, (b) asset certification, (c) federated intrusion detection and correlation, (d) Software Defined Networking (SDN) mitigation, (e) proactive islanding and (f) cybersecurity training and certification.

The evolution of cyberattacks has been significantly impacted by the rise of Artificial Intelligence (AI). In particular, AI-driven attacks leverage Machine Learning (ML) and Deep Learning (DL) methods to automate tasks like identifying vulnerabilities, crafting convincing phishing emails, and evading conventional security measures. These cyberattacks can adapt in real time, making them more elusive and challenging to detect. Furthermore, AI has enabled the development of AI-powered malware that can learn and evolve, making it even more dangerous. As AI continues to evolve, both attackers and defenders are engaged in a relentless arms race, with cybersecurity professionals striving to harness AI for threat detection and response while cybercriminals seek to exploit AI’s capabilities for their malicious purposes. This ongoing battle underscores the need for proactive and adaptive cybersecurity strategies to mitigate the evolving threats posed by AI-driven cyberattacks. Based on the aforementioned remarks, it is evident that efficient and adaptable countermeasures are necessary. In this paper, we focus our attention on Cyber Threat Intelligence (CTI) mechanisms. CTI is the process of collecting, analysing, and sharing information about potential cybersecurity threats to help organisations proactively defend against cyberattacks. In particular, after providing an overview of the CTI use cases, a brief analysis of existing solutions follows, highlighting the current trends and directions for future work in this research field.

Modern Healthcare cyberphysical systems have begun to rely more and more on distributed AI leveraging the power of Federated Learning (FL). Its ability to train Machine Learning (ML) and Deep Learning (DL) models for the wide variety of medical fields, while at the same time fortifying the privacy of the sensitive information that are present in the medical sector, makes the FL technology a necessary tool in modern health and medical systems. Unfortunately, due to the polymorphy of distributed data and the shortcomings of distributed learning, the local training of Federated models sometimes proves inadequate and thus negatively imposes the federated learning optimization process and in extend in the subsequent performance of the rest Federated models. Badly trained models can cause dire implications in the healthcare field due to their critical nature. This work strives to solve this problem by applying a post-processing pipeline to models used by FL. In particular, the proposed work ranks the model by finding how fair they are by discovering and inspecting micro-Manifolds that cluster each neural model's latent knowledge. The produced work applies a completely unsupervised both model and data agnostic methodology that can be leveraged for general model fairness discovery. The proposed methodology is tested against a variety of benchmark DL architectures and in the FL environment, showing an average 8.75% increase in Federated model accuracy in comparison with similar work.

The rapid growth of computer networks in various sectors has led to new services previously hard or impossible to implement. Internet of Things has also assisted in this evolution offering easy access to data but at the same time imposing constraints on both security and quality of service. In this paper, an SDN fault tolerant and resilient SDN controller design approach is presented. The proposed solution is suitable for a wide range of environments. Benefits stemming from actual scenarios are presented and discussed among other solutions.

The highly beneficial contribution of intelligent systems in the industrial domain is undeniable. Automation, supervision, remote control, and fault reduction are some of the various advantages new technologies offer. A protocol demonstrating high utility in industrial settings, and specifically, in smart grids, is Distributed Network Protocol 3 (DNP3), a multi-tier, application layer protocol. Notably, multiple industrial protocols are not as securely designed as expected, considering the highly critical operations occurring in their application domain. In this paper, we explore the internal vulnerabilities-by-design of DNP3, and proceed with the implementation of the attacks discovered, demonstrated through 8 DNP3 attack scenarios. Finally, we design and demonstrate a Deep Neural Network (DNN)-based, multi-model Intrusion Detection Systems (IDS), trained with our experimental network flow cyberattack dataset, and compare our solution with multiple machine learning algorithms used for classification. Our solution demonstrates a high efficiency in the classification of DNP3 cyberattacks, showing an accuracy of 99.0%.

Digital Circular Economy and Industry 5.0 have been two significant research attractions in the last years, due to the evolution of their predecessors into advanced technologies. Circular Economy (CE) has progressed into a sustainable digital approach, capable to be implemented into different scenarios. Industry 5.0 has turned from a fully automated application field into a balanced technological combination of A.I. and M.L. with the involvement of human factor, and promising enabler of Digital CE. As a result, a growing number of Digital CE models are introduced into the academic community. In this work, we collect and examine the latest research and application trends of Digital CE models, by studying their sustainable features, requirements, applications, and architectures.

The transformation of the conventional electrical grid into a digital ecosystem brings significant benefits, such as two-way communication between energy consumers and utilities, self-monitoring and pervasive controls. However, the advent of the smart electrical grid raises severe cybersecurity and privacy concerns, given the presence of legacy systems and communications protocols. This paper focuses on False Data Injection (FDI) cyberattacks against a low-voltage distribution system, taking full advantage of Man In The Middle (MITM) actions. The first cyberattack targets the communication between a smart meter and an Active Distribution Management System (ADMS), while the second FDI cyberattack targets the communication between a smart inverter and ADMS. In both cases, the cyberattacks affect the operation of the distribution transformer, thus resulting in devastating consequences. Moreover, this paper provides an Artificial Intelligence (AI)-based Intrusion Detection System (IDS), detecting and mitigating the above cyberattacks in a timely manner. The evaluation results demonstrate the efficiency of the proposed IDS.

The digitisation of the typical electrical grid introduces valuable services, such as pervasive control, remote monitoring and self-healing. However, despite the benefits, cybersecurity and privacy issues can result in devastating effects or even fatal accidents, given the interdependence between the energy sector and other critical infrastructures. Large-scale cyber attacks, such as Indostroyer and DragonFly have already demonstrated the weaknesses of the current electrical grid with disastrous consequences. Based on the aforementioned remarks, both academia and industry have already designed various cybersecurity standards, such as IEC 62351. However, dynamic risk assessment and certification remain crucial aspects, given the sensitive nature of the electrical grid. On the one hand, dynamic risk assessment intends to re-compute the risk value of the affected assets and their relationships in a dynamic manner based on the relevant security events and alarms. On the other hand, based on the certification process, new approach for the dynamic management of the security need to be defined in order to provide adaptive reaction to new threats. This paper presents a combined approach, showing how both aspects can be applied in a collaborative manner in the smart electrical grid.

The rise of the Internet of Medical Things introduces the healthcare ecosystem in a new digital era with multiple benefits, such as remote medical assistance, realtime monitoring, and pervasive control.However, despite the valuable healthcare services, this progression raises significant cybersecurity and privacy concerns.In this article, we focus our attention on the IEC 60 870-5-104 protocol, which is widely adopted in industrial healthcare systems.First, we investigate and assess the severity of the IEC 60 870-5-104 cyberattacks by providing a quantitative threat model, which relies on Attack Defence Trees and Common Vulnerability Scoring System v3.1.Next, we introduce an intrusion detection and prevention system (IDPS), which is capable of discriminating and mitigating automatically the IEC 60 870-5-104 cyberattacks.The proposed IDPS takes full advantage of the machine learning (ML) and software defined networking (SDN) technologies.ML is used to detect the IEC 60 870-5-104 cyberattacks, utilizing 1) Transmission Control Protocol/Internet Protocol network flow statistics and 2) IEC 60 870-5-104 payload flow statistics.

While the technology of Deep Learning (DL) is a powerful tool when properly trained for image analysis and classification applications, some factors for its optimization rely solely on the training data and their environment. In an effort to tackle the problem of knowledge bias created during the training process of a Deep Neural Network (DNN) and specifically Adversarial Networks for image augmentation, this work presents an entirely unsupervised methodology for discovering the unfairness level of Deep Learning (DL) models and in extend, its wrongly accumulated or biased classes. Fdi, the proposed evaluation metric for quantizing the level of unfairness of a model is introduced, along with the method of weighting the model’s knowledge and producing its weakest aspects in a data-agnostic way.

Traffic sign recognition (TSR) is a key aspect involved in the development of robust automated transportation systems. It inherently involves the task of traffic sign detection (TSD), which can be challenging due to traffic signs often being subject to deterioration or occlusion, caused by various environmental factors, or through actions of vandalism. Even though, notable advancements have been achieved in the areas of TSR and TSD, few studies have provided robust algorithms, able to be generalized in real-world applications. This mostly stems from the lack of an extensive traffic sign dataset, standardized for benchmarking purposes. In light of the aforementioned, this paper presents a novel traffic sign dataset, which consists of the Carla Traffic Sign Detection (CTSD), and the Carla Traffic Sign Recognition Dataset (CATERED), targeting the detection and recognition processes respectively. Using the proposed dataset for training and evaluation, a deep Auto-Encoder algorithm is presented, demonstrating high accuracy in detecting and recognizing the distorted traffic signs. Finally, the system is further extended to a federated learning environment, exemplifying its applicability in modern decentralized and interconnected architectures.

Internet of Things (IoT) technology such as intelligent devices, sensors, actuators and wearables have been integrated in the healthcare industry, thus contributing in the creation of smart hospitals and remote assistance environments. Ensuring the eHealth network adopts the appropriate security measures in order to effectively protect sensitive patient data against malicious attempts is a tough challenge. Devices composing eHealth infrastructure are considered to be easily exploitable. To that end, a solution monitoring the intelligent healthcare environment is of essence. In addition, by digitalising all health records, appropriate measures need to be implemented in order for patient records to be accessible by authorized personnel only. Furthermore, creating interoperable systems, capable of being integrated by multiple organizations such as hospitals and insurance companies, while maintaining a General Data Protection Regulation-friendly posture, providing access to health data is a great importance for optimal patient assistance. To address both concerns, we present a framework featuring a multi-layer tool for providing a highly effective security solution specifically designed to address the eHealth requirements, and a blockchain access control component, based on smart contracts to provide access control for authorized users to patient records and health data in a distributed way.

The rapid evolution of the Internet of Medical Things (IoMT) introduces the healthcare ecosystem into a new reality consisting of smart medical devices and applications that provide multiple benefits, such as remote medical assistance, timely administration of medication and real-time monitoring. However, despite the valuable advantages, this new reality increases the cybersecurity and privacy concerns since vulnerable IoMT devices can access and handle autonomously patients’ data. Furthermore, the continuous evolution of cyberattacks, malware and zero-day vulnerabilities require the development of the appropriate countermeasures. In the light of the aforementioned remarks, in this paper, we present an Intrusion Detection and Prevention System (IDPS), which can protect the healthcare communications that rely on the Hypertext Transfer Protocol (HTTP) and the Modbus/Transmission Control Protocol (TCP). HTTP is commonly adopted by conventional healthcare-related services, such as web-based Electronic Health Record (EHR) applications, while Modbus/TCP is an industrial protocol adopted by IoMT. Although the Machine Learning (ML) and Deep Learning (DL) methods have already demonstrated their efficacy in detecting intrusions, the rarely available intrusion detection datasets (especially in the healthcare sector) complicate their global application. The main contribution of this work lies in the fact that an active learning approach is modelled and adopted in order to re-train dynamically the supervised classifiers behind the proposed IDPS. The evaluation analysis demonstrates the efficiency of this work against HTTP and Modbus/TCP cyberattacks, showing also how the entire accuracy is increased in the various re-training phases.

In recent years and with the advancement of IoT networks, malicious intrusions aiming at disrupting the services and getting access to confidential information in medical environments is ever progressing. To that end, this paper proposes a Federated Layered Architecture to be used in Medical Cyber-Physical Systems (MCPS) Networks that entails the creation of multiple aggregation layers to induce further security to the model training process. Moreover, two Deep Adversarial Neural Networks (GANs) are presented for use with data found in the MCPS environment. The evaluation of the presented work showed that the models trained in the Federated system have an increase in their ability to detect possible intrusions in the MCPS network than the commonly trained models.

Ultra-low latency connections for a massive number of devices are one of the main requirements of the next-generation tactile Internet-of-Things (TIoT). Grant-free non-orthogonal multiple access (GF-NOMA) is a novel paradigm that leverages the advantages of grant-free access and non-orthogonal transmissions, to deliver ultra-low latency connectivity. In this work, we present a joint channel assignment and power allocation solution for semi-GF-NOMA systems, which provides access to both grant-based (GB) and grant-free (GF) devices, maximizes the network throughput, and is capable of ensuring each device’s throughput requirements. In this direction, we provide the mathematical formulation of the aforementioned problem. After explaining that it is not convex, we propose a solution strategy based on the Lagrange multipliers and subgradient method. To evaluate the performance of our solution, we carry out system-level Monte Carlo simulations. The simulation results indicate that the proposed solution can optimize the total system throughput and achieve a high association rate, while taking into account the minimum throughput requirements of both GB and GF devices.

In 5G and beyond telecommunication infrastructures a crucial challenge in achieving the strict Key Performance Indicators (KPIs) regarding capacity, latency, and guaranteed quality of service, is the efficient handling of the fronthaul bottleneck. This part of the next generation networks is expected to comprise the New Radio (NR) access and the Next Generation Passive Optical Network (NGPON) domains. Latest developments load the fronthaul with computing tasks as well (e.g., for AI-based processes) in the context of Mobile Edge Computing (MEC). Towards efficient management of all resource types, this paper proposes a joint allocation scheme with three optimization phases for radio, optical, and MEC resources. This scheme, which has been developed in the context of the blueSPACE 5G Infrastructure Public Private Partnership (5G PPP) project, exploits cutting-edge technologies, such as radio beamforming, spatial-spectral granularity in optical networks, and Network Function Virtualization (NFV), to provide dynamic, adaptive, and energy efficient allocation of resources. The devised model is mathematically described and the overall solution is evaluated in a realistic simulation scenario, demonstrating its effectiveness.

Industrial Internet of Things (IIoT) is a relatively new area of research that utilises multidisciplinary and holistic approaches to develop smart solutions for complex problems in industrial environments. Designing applications for the IIoT is a non trivial issue and requires to address, among many others, technology concerns, the protection of personal data, and the privacy of individuals. In this review paper, we identify privacy-preserving solutions that have been proposed in the literature to safeguard the privacy of individuals being part, or interacting with, the IIoT environment. As such, it considers two main categories of the analysed protocols, i.e., the privacy-preserving data management and processing solutions, and the privacy-preserving authentication methods.

Agriculture is by its nature a complicated scientific field, related to a wide range of expertise, skills, methods and processes which can be effectively supported by computerized systems. There have been many efforts towards the establishment of an automated agriculture framework, capable to control both the incoming data and the corresponding processes. The recent advances in the Information and Communication Technologies (ICT) domain have the capability to collect, process and analyze data from different sources while materializing the concept of agriculture intelligence. The thriving environment for the implementation of different agriculture systems is justified by a series of technologies that offer the prospect of improving agricultural productivity through the intensive use of data. The concept of big data in agriculture is not exclusively related to big volume, but also on the variety and velocity of the collected data. Big data is a key concept for the future development of agriculture as it offers unprecedented capabilities and it enables various tools and services capable to change its current status. This survey paper covers the state-of-the-art agriculture systems and big data architectures both in research and commercial status in an effort to bridge the knowledge gap between agriculture systems and exploitation of big data. The first part of the paper is devoted to the exploration of the existing agriculture systems, providing the necessary background information for their evolution until they have reached the current status, able to support different platforms and handle multiple sources of information. The second part of the survey is focused on the exploitation of multiple sources of information, providing information for both the nature of the data and the combination of different sources of data in order to explore the full potential of ICT systems in agriculture.

Climate change has introduced significant challenges that can affect multiple sectors, including the agricultural one. In particular, according to the Food and Agriculture Organization of the United Nations (FAO) and the International Telecommunication Union (ITU), the world population has to find new solutions to increase the food production by 70% by 2050. The answer to this crucial challenge is the suitable adoption and utilisation of the Information and Communications Technology (ICT) services, offering capabilities that can increase the productivity of the agrochemical products, such as pesticides and fertilisers and at the same time, they should minimise the functional cost. More detailed, the advent of the Internet of Things (IoT) and specifically, the rapid evolution of the Unmanned Aerial Vehicles (UAVs) and Wireless Sensor Networks (WSNs) can lead to valuable and at the same time economic Precision Agriculture (PA) applications, such as aerial crop monitoring and smart spraying tasks. In this paper, we provide a survey regarding the potential use of UAVs in PA, focusing on 20 relevant applications. More specifically, first, we provide a detailed overview of PA, by describing its various aspects and technologies, such as soil mapping and production mapping as well as the role of the Global Positioning Systems (GPS) and Geographical Information Systems (GIS). Then, we discriminate and analyse the various types of UAVs based on their technical characteristics and payload. Finally, we investigate in detail 20 UAV applications that are devoted to either aerial crop monitoring processes or spraying tasks. For each application, we examine the methodology adopted, the proposed UAV architecture, the UAV type, as well as the UAV technical characteristics and payload.

Smart video sensors for applications related to surveillance and security are IOT-based as they use Internet for various purposes. Such applications include crowd behaviour monitoring and advanced decision support systems operating and transmitting information over internet. The analysis of crowd and pedestrian behaviour is an important task for smart IoT cameras and in particular video processing. In order to provide related behavioural models, simulation and tracking approaches have been considered in the literature. In both cases ground truth is essential to train deep models and provide a meaningful quantitative evaluation. We propose a framework for crowd simulation and automatic data generation and annotation that supports multiple cameras and multiple targets. The proposed approach is based on synthetically generated human agents, augmented frames and compositing techniques combined with path finding and planning methods. A number of popular crowd and pedestrian data sets were used to validate the model, and scenarios related to annotation and simulation were considered.

Sensor-based networks have been proposed as a method for the continuous and remote monitoring of patients with chronic illness. Hence, healthcare professionals need to read and provide feedback on the gathered sensor data which represent patient's vital signs. This qualitative study examined healthcare professionals' attitudes towards the application of remote patient monitoring through sensor networks in developing regions using semi-structured interviews. Thematic analysis of the interview data revealed that healthcare professionals have experience with digital technologies, moreover, they are willing to use other more advanced technologies that are, wireless, accurate and enable remote and real-time monitoring of patients. According to the healthcare professionals, the benefits of sensor-based networks are: recording patient's vital signs for longer periods of time; facilitating clinical decision-making; and helping them in providing better treatment which will have a positive impact in the patient's life. This study confirms that trainings provided to medical personnel before the application of the digital platforms in healthcare helped them to easily adapt these technologies. Furthermore, it did not appear that age was a problem to use digital monitoring technologies in healthcare. Nevertheless, healthcare professionals confirmed that possible limitations for providing distance-based monitoring in developing regions and giving feedback is related to patient's education and maturity to obey to doctor's suggestions, doctor's commitments and available time and the financial aspect of communicating with a patient at a distance.

Internet of Things (IoT) constitutes the next step in the field of technology, bringing enormous changes in industry, medicine, environmental care, and urban development. Various challenges are to be met in forming this vision, such as technology interoperability issues, security and data confidentiality requirements, and, last but not least, the development of energy efficient management systems. In this paper, we explore existing networking communication technologies for the IoT, with emphasis on encapsulation and routing protocols. The relation between the IoT network protocols and the emerging IoT applications is also examined. A thorough layer‐based protocol taxonomy is provided, while how the network protocols fit and operate for addressing the recent IoT requirements and applications is also illustrated. What is the most special feature of this paper, compared to other survey and tutorial works, is the thorough presentation of the inner schemes and mechanisms of the network protocols subject to IPv6. Compatibility, interoperability, and configuration issues of the existing and the emerging protocols and schemes are discussed based on the recent advanced of IPv6. Moreover, open networking challenges such as security, scalability, mobility, and energy management are presented in relation to their corresponding features. Lastly, the trends of the networking mechanisms in the IoT domain are discussed in detail, highlighting future challenges.

Machine-type communication (MTC) provides a potential playground for deploying machine-to-machine (M2M), IP-enabled `things' and wireless sensor networks (WSNs) that support modern, added-value services and applications. 4G/5G technology can facilitate the connectivity and the coverage of the MTC entities and elements by providing M2M-enabled gateways and base stations for carrying traffic streams to/from the backbone network. For example, the latest releases of long-term evolution (LTE) such as LTE-Advanced (LTE-A) are being transformed to support the migration of M2M devices. MTC-oriented technical definitions and requirements are defined to support the emerging M2M proliferation. ETSI describes three types of MTC access methods, namely a) the direct access, b) the gateway access and c) the coordinator access. This work is focused on studying coverage aspects when a gateway access takes place. A deployment planar field is considered where a number of M2M devices are randomly deployed, e.g., a hospital where body sensor networks form a M2M infrastructure. An analytical framework is devised that computes the average number of connected M2M devices when a M2C gateway is randomly placed for supporting connectivity access to the M2M devices. The introduced analytical framework is verified by simulation and numerical results.

The paper explores the potential of usage and ranking information in increasing student engagement in a double-blinded peer review setting, where students are allowed to select freely which/how many peer works to review. The study employed 56 volunteering sophomore students majoring in Informatics and Telecommunications Engineering. We performed a controlled experiment, grouping students into 3 study conditions: control, usage data, usage and ranking data. Students in the control condition did not receive additional information. Students in the next two conditions were able to see their usage data (logins, peer work viewed/reviewed, etc.), while students in the last group could additionally see their ranking in their group according to their usage data. Results showed that while the three groups were comparable, a range of different attitudes were visible in the Ranking group. Students with more positive attitude towards ranking were more engaged and outperformed their fellow students in their group.

One of the most challenging requirements in cutting-edge Mobile Ad hoc Networks is the need for adaptive and efficient routing. Networks capable of adapting their behavior based on current conditions are often characterized as self-organizing networks, which are lately considered very promising for future applications. This work examines the impact of the different mobility properties on the performance of self-organizing networks. For that purpose, a simulator was developed to model different mobility patterns and study the way they affect the effectiveness of the well-known AODV routing protocol. Particularly, this paper focuses on the effect of the different mobility schemes on network topology and consequently to the overall network performance. The results reveal the tight correlations between node mobility characteristics and network metrics.

This paper focuses on the effect that usage data and group ranking information may have when are presented to students in a peer review setting. The study analyzes the performance and attitudes of 56 sophomore students enrolled in a Network Planning and Design course. The students, grouped randomly in three different conditions, followed the prescriptions of a free-selection peer review protocol that guided students in double-blind review process, allowing them to select on their own peer work for review. Students in the first condition acted as the control group without any information on their usage data or rankings. Students in the second condition had access to usage data information mirroring their activity in the study, while students in the third condition received additional information on their rankings inside their group. Result analysis suggests that, while there is not difference in domain knowledge acquisition, engagement was higher in the third group, with students spending more time in the activity and expressing a more positive attitude towards the study.

This paper introduces an adaptive spectrum sensing method for cognitive radio wireless networks. The proposed method enhances previously proposed random-based sensing policies, effectively selecting the licensed channels to be sensed by accurately estimating channels' availability, resulting, thus, to high system's resources utilization. The core mechanism of the adaptive method is an enhanced learning automaton, which efficiently interacts with the environment and provides accurate decisions on selecting the channel to be sensed on behalf of the secondary users. A thorough description of the introduced method is provided, while the performance of the enhanced sensing policies is verified through extensive simulation experiment.

This paper presents design guidelines for implementing a free-selection peer review protocol. "Free-selection" (FS) refers to the ability of students freely access all available peer work and choose which of them to read and review. A series of two studies on the free-selection protocol has provided evidence on the efficiency of the method. In the First study, the FS protocol was compared against the widely used assigned-pair (AP) one, where students work in instructor-defined dyads. In the Second study, further issues of the FS approach were evaluated, with our attention focused on students who, due to the freedom element of the protocol, do not receive reviews. Both studies paint a very promising picture of free-selection. However, several issues were also raised on how to effectively apply such a protocol. As the use of technology is necessary in the FS approach, we provide in this paper the design implications derived from the two studies regarding various aspects of the protocol.

IEEE 802.11e Enhanced Distributed Channel Access (EDCA) is developed to provide Wireless Local Area Networks (WLANs) with Quality of Service (QoS) support. Several solutions have been proposed in order to provide a fair channel access for all competing stations. This paper first studies the QoS capabilities of the Adaptive Weighted and Prioritized Polling (AWPP) protocol that adopts the frame structure and the basic polling scheme of the Priority Oriented Adaptive Polling (POAP) protocol. Our analytical approach is validated by plotting analytical results against simulation outcome. We then explore the fairness provision of the AWPP protocol utilizing Jain's fairness index. Finally, we provide a comparative performance analysis between EDCA, POAP and AWPP protocols and we demonstrate that AWPP outperforms the other two.

Cooperative wireless networks supporting multiple services necessitate the application of a robust bandwidth allocation policy to ensure Quality of Service (QoS) provision to different applications. In this work, a load dependent bandwidth allocation technique is presented considering traffic priority and buffer load in the relay nodes of a cooperative communication network. An analytical approach for bandwidth sharing is provided along with a delay analysis, verifying that the proposed scheme can efficiently provide traffic differentiation, satisfying, also, the QoS requirements in terms of bandwidth, packet transmission rate and delay. The results obtained by the analysis are validated via simulations, confirming the improved network performance in terms of throughput and delay.

Today’s wireless LANs require efficient integration of multimedia and traditional data traffic. Multimedia network applications are time-bounded and have stricter QoS demands. The IEEE 802.11e workgroup is standardizing a new QoS enhanced access scheme for wireless networks. It is based on a mechanism called Enhanced Distributed Channel Access (EDCA). EDCA seems capable of differentiating the traffic, however, it exhibits great overhead that limits the actually available bandwidth and degrades the overall performance. This work proposes an alternative protocol which could be used in place of EDCA. The Priority Oriented Adaptive Polling (POAP) is collision free, it prioritizes the different kinds of traffic, and it is able to provide QoS for all types of multimedia network applications, while efficiently supporting background data traffic. POAP compared to EDCA, provides higher channel utilization, distributes network resources to the mobile stations adapting to their real needs, and generally exhibits superior performance.