Manuel Fernandez-Veiga

• University of Vigo

Messaging Layer security (MLS) and its underlying Continuous Group Key Agreement (CGKA) protocol allows a group of users to share a cryptographic secret in a dynamic manner, such that the secret is modified in member insertions and deletions. One of the most relevant contributions of MLS is its efficiency, as its communication cost scales logarithm...

The advance of quantum computing poses a significant threat to classical cryptography, compromising the security of current encryption schemes such as RSA and ECC. In response to this challenge, two main approaches have emerged: quantum cryptography and post-quantum cryptography (PQC). However, both have implementation and security limitations. In...

Nowadays, 5G architecture is characterized by the use of monolithic hardware, where the configuration of its elements is completely proprietary for each manufacturer. In recent years, as an alternative to this centralized architecture, a new model has emerged: the Open Radio Access Network (Open RAN). One of its main features has been the split of...

We implement a set of simulation experiments in NetSquid specifically designed to estimate the end-to-end fidelity across a path of quantum repeaters or quantum switches. The switch model includes several generalizations that are not currently available in other tools and are useful for gaining insight into practical and realistic quantum network e...

Key material plays a critical role in cryptography. Devices that are unable to generate high-quality keys are exposed to multiple vulnerabilities. In this work, we present an Entropy-as-a-Service (EaaS) architecture to address this problem. The proposed solution creates secure keys and sends them to a mobile application using a Quantum Random Numbe...

We implement a simulation environment on top of NetSquid that is specifically designed for estimating the end-to-end fidelity across a path of quantum repeaters or quantum switches. The switch model includes several generalizations which are not currently available in other tools, and are useful for gaining insight into practical and realistic quan...

We implement a simulation environment on top of NetSquid that is specifically designed for estimating the end-to-end fidelity across a path of quantum repeaters or quantum switches. The switch model includes several generalizations which are not currently available in other tools, and are useful for gaining insight into practical and realistic quan...

Federated Learning (FL) emerges as a distributed machine learning approach that addresses privacy concerns by training AI models locally on devices. Decentralized Federated Learning (DFL) extends the FL paradigm by eliminating the central server, thereby enhancing scalability and robustness through the avoidance of a single point of failure. Howeve...

Messaging Layer security (MLS) and its underlying Continuous Group Key Agreement (CGKA) protocol allows a group of users to share a cryptographic secret in a dynamic manner, such that the secret is modified in member insertions and deletions. Although this flexibility makes MLS ideal for implementations in distributed environments, a number of issu...

The first Quantum Key Distribution (QKD) networks are currently being deployed, but the implementation cost is still prohibitive for most researchers. As such, there is a need for realistic QKD network simulators. The QKDNetSim module for the network simulator NS-3 focuses on the representation of packets and the management of key material in a QKD...

Securing online financial transactions has become a critical concern in an era where financial services are becoming more and more digital. The transition to digital platforms for conducting daily transactions exposed customers to possible risks from cybercriminals. This study proposed a framework that combines multi-factor authentication and machi...

Multicast transmission is the natural approach to efficiently transport data from a source to multiple receivers using minimum network bandwidth. Two incompatible options exist to realize this multicast support: the classical one is the design and deployment of a specific multicast routing protocol at the network layer, and the other one is the shi...

Quantum Key Distribution (QKD) is a promising technology that allows two nodes to privately agree on a key through a quantum channel. Unfortunately, QKD is still in experimental phase and researchers must rely on simulators to replicate the behaviour of a quantum network. One of the most widespread is QKDNetSim, a module for the C++ network simulat...

A communication protocol for the distribution of cryptographic keys generated by a quantum random number generator (QRNG) has been developed by introducing a minor modification to Kerberos and using SRP as the authentication mechanism. The protocol, named Qerberos, allows two users to acquire the same symmetric key generated by a trusted third par...

In the last years of the past century, complex correlation structures were empirically observed, both in aggregated and individual traffic traces, including long-range dependence, large-timescale self-similarity and multi-fractality. The use of stochastic processes consistent with these properties has opened new research fields in network performan...

In this paper, we study via simulation the performance of irregular repetition slotted ALOHA under multi-packet detection and different patterns of the load process. On the one hand, we model the arrival process with a version of the M/G/∞ process able to exhibit a correlation structure decaying slowly in time. Given the independence among frames i...

In mobile networks, 5G Ultra-Dense Networks (UDNs) have emerged as they effectively increase the network capacity due to cell splitting and densification. A Base Station (BS) is a fixed transceiver that is the main communication point for one or more wireless mobile client devices. As UDNs are densely deployed, the number of BSs and communication l...

Abstract—Federated Learning (FL) is a distributed machine learning paradigm in which a large number of clients coordinate with a central server to learn a model without sharing their own training data. One central server is not enough, due to problems of connectivity with clients. In this paper, a Decentralized Federated Learning (DFL) model with t...

In this study, as the last step of a longitudinal study of the impact of social learning and gamification methodologies on learning results in higher education, we have recorded the activity in a software platform based on Moodle, specially built for encouraging online participation of the students to design, carry out and evaluate a set of learnin...

Machine learning (ML) and especially deep learning (DL) with neural networks have demonstrated an amazing success in all sorts of AI problems, from computer vision to game playing, from natural language processing to speech and image recognition. In many ways, the approach of ML toward solving a class of problems is fundamentally different than the...

We present in this paper an analysis of the effect of gamification and social learning/teaching on the performance of students. We identify course variables that quantitatively explain the improvements reported when using these methodologies integrated in the course design, and apply techniques from the machine learning domain to conduct success/fa...

The semantic web is considered to be an extension of the present web. In the semantic web, information is given with well-defined meanings, and thus helps people worldwide to cooperate together and exchange knowledge. The semantic web plays a significant role in describing the contents and services in a machine-readable form. It has been developed...

The activity of students in online forums within an online learning platform is readily captured as a directed network graph whose structural and dynamic properties can be used to anticipate with good accuracy their level of performance in the future. In this chapter, we present and analyze a case study for this claim. Our data source is a complete...

Non-orthogonal multiple access (NOMA) techniques have emerged in the past years as a solution to approximate the throughput performance of wireless communications systems to their theoretical capacity region. We consider in this paper an optimization-based model for multicast device-to-device (MD2D) communications where the channels are not orthogo...

Social networks based on mutual interest, affinity or leadership are spontaneously generated when the training activities are carried out through online learning systems wherein collaboration and interaction among participants is encouraged. The bare structure of those interactions, reflected in a network graph, is known to contain relevant statist...

In this paper, we address the optimization of the energy efficiency of underlay multicast device-to-device (D2MD) communications on cellular networks. In particular, we maximize the energy efficiency of both the global network and the individual users considering various fairness factors such as maximum power and minimum rate constraints. For this,...

Social learning environments (SLEs) are software suites that enable the application of both traditional and innovative teaching methodologies, blending activities tailored to the specific goals of the teaching style. In particular, SLEs have been used to introduce, on a medium and large scale, gamification strategies as a complement to traditional...

In order to meet the requirements of services and applications envisioned for post-5G and 6G networks, research efforts are heading towards the convergence of architectures aiming to support the wide variety of new compute-demanding and latency-sensitive applications in the context of Tactile Internet. In this paper, we study the resource allocatio...

In this paper, we optimize the energy efficiency (bits/s/Hz/J) of device-to-multi-device (D2MD) wireless communications. While the device-to-device scenario has been extensively studied to improve the spectral efficiency in cellular networks, the use of multicast communications opens the possibility of reusing the spectrum resources also inside the...

In this paper, we optimize the energy efficiency of device-to-multi-device (D2MD) communications. While point-to-point has been extensively studied to improve the spectral efficiency in cellular networks, the introduction of multicast communications brings, in addition, the possibility of reusing the spectrum resources also inside the groups. We fo...

Frame coalescing is one of the most efficient techniques to manage the low power idle (LPI) mode supported by Energy Efficient Ethernet (EEE) interfaces. This technique enables EEE interfaces to remain in the LPI mode for a certain amount of time upon the arrival of the first frame (time-based coalescing) or until a predefined amount of traffic acc...

Frame coalescing is one of the most efficient techniques to manage the low power idle (LPI) mode supported by Energy Efficient Ethernet (EEE) interfaces. This technique enables EEE interfaces to remain in the LPI mode for a certain amount of time upon the arrival of the first frame (time-based coalescing) or until a predefined amount of traffic acc...

In this paper we discuss the implementation of an ONOS application that leverages Energy-Efficient Ethernet links between a pair of switches and shares incoming traffic among the link in the way that minimizes overall energy usage. As the straightforward solution can result in excessive traffic delay, we provide two alternative solutions to meet th...

During the last few years, there has been plenty of research for reducing energy consumption in telecommunication infrastructure. However, many of the proposals remain unim-plemented due to the lack of flexibility in legacy networks. In this paper we demonstrate how the software defined networking (SDN) capabilities of current networking equipment...

Both economic and environmental costs are driving much research in the area of the energy efficiency of networking equipment. This research has produced a great amount of proposals. However, the majority of them remain unimplemented due to the lack of flexibility of current hardware devices and a certain lack of enthusiasm from commercial vendors....

In this paper we discuss the implementation of an ONOS application that leverages Energy-Efficient Ethernet links between a pair of switches and shares incoming traffic among the link in the way that minimizes overall energy usage. As the straightforward solution can result in excessive traffic delay, we provide two alternative solutions to meet th...

Energy efficiency of cellular networks can be greatly improve if base stations (BSs) can be put into a low power operation mode during low load periods. In this paper, we present a new dynamic scheme to manage the sleep mode of energy-aware BSs that can be autonomously governed. This kind of BSs, such as those operating in heterogeneous or hyper-ce...

Earlier studies have shown the power of online learning systems data to develop prediction methods that try to identify successful students patterns of accomplishment and engagement to allow timely pedagogical interventions. Our learning platform, SocialWire, collects a detailed record of the students' activity so, in this paper, we compare and com...

During the last few years, there has been plenty of research for reducing energy consumption in telecommunication infrastructure. However, many of the proposals remain unimplemented due to the lack of flexibility in legacy networks. In this paper we demonstrate how the software defined networking (SDN) capabilities of current networking equipment c...

The widespread use of computing and communications technologies has also arrived at the education field, an area where general and custom-designed online social networking software platforms are being increasingly employed in formal course offerings at all education levels. Despite the widespread use of open online social networks (OSN), the relati...

The widespread use of computing and communications technologies has enabled the popularity of social networks oriented to learn. Earlier studies have shown the power of online learning systems data to develop prediction methods that try to identify successful students patterns of accomplishment and engagement to allow timely pedagogical interventio...

Networking operational costs and environmental concerns have lately driven the quest for energy efficient equipment. In wired networks, energy efficient Ethernet (EEE) interfaces can greatly reduce power demands when compared to regular Ethernet interfaces. Their power saving capabilities have been studied and modeled in many research articles in t...

The IEEE 802.3bj standard defines two potential low power operating modes for high speed Energy Efficient Ethernet (EEE) physical interfaces working at 40 and 100Gb/s: a not so efficient low power mode that requires very short transition times to restore normal operation (Fast-Wake) and a highly efficient low power mode with longer transition times...

Networking operational costs and environmental concerns have lately driven the quest for energy efficient equipment. In wired networks, energy efficient Ethernet (EEE) interfaces can greatly reduce power demands when compared to regular Ethernet interfaces. Their power saving capabilities have been studied and modeled in many research articles in t...

The widespread use of computing and communications technologies has enabled the popularity of social networks oriented to learn. Earlier studies have shown the power of online learning systems data to develop prediction methods that try to identify successful students patterns of accomplishment and engagement to allow timely pedagogical interventio...

Underlay device to device multicast communication brings great benefits to cellular networks in term of energy and spectral efficiency, since a group of users can communicate directly by reusing cellular resources. In this paper, we propose a scheme to maximize network energy efficiency (EE) through transmission power control. In addition, to get a...

The widespread use of computing and communications technologies has enabled the popularity of social networks oriented to learn. In this work, we study the nature and strength of associations between students using an online social network embedded in a learning management system. With datasets from three offerings of the same course, we mined the...

The widespread use of computing and communications technologies has enabled the popularity of social networks oriented to learn. In a previous work, we studied the nature and strength of associations between undergraduate students of an introductory course on computer networks, using an online social network embedded in a learning management system...

In order to cope with the ever increasing traffic load that networks will need to support, a new approach for planning cellular networks deployments should be followed. Traditionally, cell association and resource allocation has been based on the received signal power but this approach seems to be inadequate regarding the brewing of heterogeneous n...

It is commonly accepted that contemporary cohorts of students witness and experience the benefits of information technologies in their learning processes. The so-called “digital natives” acquire, as a consequence of their early exposure to these technologies, different patterns of work, distinct attention conducts, new learning preferences and, gen...

The invention relates to a device (102) and method for energy savings in network interfaces which obtains maximum energy savings while at the same time allows controlling the mean delay of the frames to be transmitted. The device comprises an energy-saving management module (LPI) (201) controlling use of the energy-saving modes provided for in stan...

Receiver-initiated medium access control protocols for wireless sensor networks are theoretically able to adapt to changing network conditions in a distributed manner. However, existing algorithms rely on fixed beacon rates at each receiver. We present a new received initiated MAC protocol that adapts the beacon rate at each receiver to its actual...

Rising energy consumption of IT infrastructure concerns have spurred the development of more power efficient networking equipment and algorithms. When old equipment just drew an almost constant amount of power regardless of the traffic load, there were some efforts to minimize the total energy usage by modifying routing decisions to aggregate traff...

The IEEE has recently released the 802.3bj standard that defines two different low power operating modes for high speed Energy Efficient Ethernet physical interfaces (PHYs) working at 40 and 100 Gb/s. In this paper, we propose the use of the well-known frame coalescing algorithm to manage them and provide an analytical model to evaluate the influen...

The Discontinuous Reception (DRX) mechanism is commonly employed in current LTE networks to improve energy efficiency of user equipment (UE). DRX allows UEs to monitor the physical downlink control channel (PDCCH) discontinuously when there is no downlink traffic for them, thus reducing their energy consumption. However, DRX power savings are achie...

The Discontinuous Reception (DRX) mechanism is commonly employed in current LTE networks to improve energy efficiency of user equipment (UE). DRX allows UEs to monitor the physical downlink control channel (PDCCH) discontinuously when there is no downlink traffic for them, thus reducing their energy consumption. However, DRX power savings are achie...

The energy demands of Ethernet links have been an active focus of research in the recent years. This work has enabled a new generation of Energy Efficient Ethernet (EEE) interfaces able to adapt their power consumption to the actual traffic demands, thus yielding significant energy savings. With the energy consumption of single network connections...

The energy demands of Ethernet links have been an active focus of research in the recent years. This work has enabled a new generation of energy-efficient Ethernet (EEE) interfaces able to adapt their power consumption to the actual traffic demands, thus yielding significant energy savings. With the energy consumption of single network connections...

It is commonly accepted that contemporary cohorts of students witness and experience the benefits of information technologies in their learning processes. The so-called ``digital natives'' acquire, as a consequence of their early exposure to these technologies, different patterns of work, distinct attention conducts, new learning preferences and, g...

The vast majority of popular Internet applications are controlled by TCP. The provision of end-to-end quantitative QoS guarantees to individual TCP flows is thus an exceedingly interesting problem, facilitating new business models for the Internet and therefore encouraging investments on the part of Internet Service Providers (ISPs). However, altho...

Current networking equipment usually provides several energy profiles with different performance capabilities. For example, in EPON systems, ONUs are able to switch their transmitters off when there is no data to transmit. This low power mode, known as doze mode, can significantly reduce power consumption in EPONs if wisely used. In this paper, we...

Resulta ampliamente aceptado que nos encontramos ante una generación de estudiantes caracterizada por encontrarse ante un espectacular desarrollo de las tecnologías de la información y las comunicaciones, los llamados ``nativos digitales'', y que como consecuencia de ello poseen diferentes patrones de trabajo, atención y preferencias de aprendizaje...

Proportional fairness is a widely accepted form of allocating transmission resources in communication systems. For wired networks, the combination of a simple probabilistic packet marking strategy together with a scheduling algorithm aware of two packet classes can meet a given proportional vector of n loss probabilities, to an arbitrary degree of...

This paper describes a network architecture for supporting interdomain QoS in hierarchical topologies with multiple ISPs, as the Internet. We propose the combination of a loss differentiation mechanism in access ISPs and a mechanism which guarantees bandwidth to aggregates of flows in the upper tier in order to achieve end-to-end proportional diffe...

The IEEE 802.3az standard provides a mechanism to build energy efficient Ethernet interfaces via a low power idle mode that they can enter when there is no data to transmit. Several competing algorithms have appeared that make use of this mode to minimize energy consumption with little disruption to the traffic. Two algorithms stand out among those...

The IEEE 802.3az standard provides a new low power mode that Ethernet network interfaces can use to save energy when there is no traffic to transmit. Simultaneously with the final standard approval, several algorithms were proposed to govern the physical interface state transition between the normal active mode and the new low power mode. In fact,...

Switching the operating state on machines is probably the simpler way to reduce the energy consumption of otherwise non energy-aware devices. Indeed, many energy-aware systems allow two states of operation: a low power idle (LPI) mode, in which the system is unable to process data, and a fully working mode. For networking equipment, packet coalesci...

Social networks are being massively utilized for targeting consumers, as entertainment channels and in personal communications, but also offer an appealing potential as a tool for learning in higher education, largely unexplored yet. This paper describes the design and implementation of a social network platform aimed at integrating informal learni...