Pedro R. M. Inácio

Universidade da Beira Interior | UBI · Department of Computer Science

Virtual machine placement and migration (VMPM) are key operations for managing cloud resources. Considering the large scale of cloud infrastructures, several proposals still fail to provide a comprehensive and scalable solution. A variety of approaches have been used to address this issue, e.g., the modern portfolio theory (MPT). Originally formula...

Deep Learning is currently used to perform multiple tasks, such as object recognition, face recognition, and natural language processing. However, Deep Neural Networks (DNNs) are vulnerable to perturbations that alter the network prediction (adversarial examples), raising concerns regarding its usage in critical areas, such as self-driving vehicles...

Current Active Speaker Detection (ASD) models achieve great results on AVA-ActiveSpeaker (AVA), using only sound and facial features. Although this approach is applicable in movie setups (AVA), it is not suited for less constrained conditions. To demonstrate this limitation, we propose a Wilder Active Speaker Detection (WASD) dataset, with increase...

Virtual machine placement and migration (VMPM) are key operations for managing cloud resources. Considering the large scale of cloud infrastructures, several proposals still fail to provide a comprehensive and scalable solution. A variety of approaches have been used to address this issue, e.g., the modern portfolio theory (MPT). Originally formula...

Virtual machine placement and migration (VMPM) are key operations for managing cloud resources. Considering the large scale of cloud infrastructures, several proposals still fail to provide a comprehensive and scalable solution. A variety of approaches have been used to address this issue, e.g., the modern portfolio theory (MPT). Originally formula...

The adoption and popularization of mobile devices, such as smartphones and tablets, accentuated after the second decade of this century, has been motivated by the growing number of mobile applications, which can solve problems in different areas of contemporary societies. Conversely, the software development industry is motivated by the increasing...

During the COVID-19 pandemic, universities worldwide were forced to close, causing a shift from presential to remote classes. This situation motivated teachers to find suitable tools to evaluate students remotely, fairly, and accurately. However, currently available systems are either survey or exercise evaluation based, not suitable for competency...

Internet traffic classification aims to identify the kind of Internet traffic. With the rise of traffic encryption and multi-layer data encapsulation, some classic classification methods have lost their strength. In an attempt to increase classification performance, Machine Learning (ML) strategies have gained the scientific community interest and...

Home users are increasingly acquiring, at lower prices, electronic devices such as video cameras, portable audio players, smartphones, and video game devices, which are all interconnected through the Internet. This increase in digital equipment ownership induces a massive production and sharing of multimedia content between these users. The supervi...

Fruit detection is crucial for yield estimation and fruit picking system performance. Many state-of-the-art methods for fruit detection use convolutional neural networks (CNNs). This paper presents the results for peach detection by applying a faster R-CNN framework in images captured from an outdoor orchard. Although this method has been used in o...

Cybercrime affects companies worldwide, costing millions of dollars annually. The constant increase of threats and vulnerabilities raises the need to handle vulnerabilities in a prioritized manner. This prioritization can be achieved through Common Vulnerability Scoring System (CVSS), typically used to assign a score to a vulnerability. However, th...

The potential for being the target of Denial of Service (DoS) attacks is one of the most severe security threats on the Internet. Attackers have been modifying their attack format over the years, damaging specific conditions of operating systems and protocols in an attempt to deny or diminish the quality of the service provided to legitimate users....

Virtual machine placement and migration (VMPM) are key operations for management of cloud resources. Considering the large scale of cloud infrastructures, several proposals lack in providing a comprehensive and scalable solution. A variety of approaches have been used to address this issue, such as the modern portfolio theory (MPT). Originally form...

The advent of wireless technologies and the development of more and better globally connected mobile devices, leverage real time health monitoring. Mobile health (m-health) promise to deliver health services anytime and anywhere, improving user convenience and enabling faster diagnoses without the need to travel to healthcare facilities. The use of...

Bug triaging is a critical and time-consuming activity of software maintenance. This paper aims to present an automated heuristic approach combined with fuzzy multi-criteria decision-making for bug triaging. To date, studies lack consideration of multi-criteria inputs to gather decisive and explicit knowledge of bug reports. The proposed approach b...

The applications of Internet of Things (IoT) and associated technologies have been spreading rapidly across a wide range of domains, including environmental monitoring, home automation, and supply chain, having a significant bearing on the social and economic well-being of humans as well as enhancing environmental sustainability. In recent years, h...

Distributed Denial of Service (DDoS) attacks are still among the most dangerous attacks on the Internet. With the advance of methods for detecting and mitigating these attacks, crackers have improved their skills in creating new DDoS attack types with the aim of mimicking normal traffic behaviour therefore becoming silently powerful. Among these ad...

With the advent of cryptocurrencies and blockchain, the growth and adaptation of cryptographic features and capabilities were quickly extended to new and underexplored areas, such as healthcare. Currently, blockchain is being implemented mainly as a mechanism to secure Electronic Health Records (EHRs). However, new studies have shown that this tech...

In recent years, the Internet of Things (IoT) security and privacy have been receiving growing attention among researchers in both academia and industry, resulting in various innovative IoT security and privacy solutions. While research approaches and findings may vary considerably across different studies, the consensus is that a key prerequisite...

The limitations of traditional classification methods based on port number and payload inspection to classify encrypted or obfuscated Internet traffic have led to significant research efforts focusing on classification approaches based on Machine Learning techniques using Transport Layer statistical features. However, these approaches also have the...

Over the years, pervasive computing and communication technologies have enabled the emergence of new computing paradigms that have gained importance across a wide spectrum of domains. The three most notable that have witnessed significant advancements and have a solid track record of exponential growth in diverse applications are the Internet of Th...

Background: Smartphones can tackle healthcare stakeholders' diverse needs. Nonetheless, the risk of data disclosure/breach can be higher when using such devices, due to the lack of adequate security and the fact that a medical record has a significant higher financial value when compared with other records. Means to assess those risks are required...

The past couple of years have marked continued growth in the applications and services of the Internet of Things (IoT). This has attracted the attention of new operators as well as institutional, corporate, and private investors in every sector of the economy, and as a result, new businesses are springing up rapidly. These include many start-up com...

This book presents papers from HealthyIoT 2018, the fifth edition of an international scientific event series dedicated to Internet of Things and Healthcare. The papers discuss leveraging a set of existing and emerging technologies, notions and services that can provide many solutions to delivery of electronic healthcare, patient care, and medical...

Trusted platform modules (TPM) have become important safe‐guards against variety of software‐based attacks. By providing a limited set of cryptographic services through a well‐defined interface, separated from the software itself, TPM can serve as a root of trust and as a building block for higher‐level security measures. This article surveys the l...

With the advent of Bitcoin and blockchain, the growth and adaptation of cryptographic features and capabilities were quickly extended to new and underexplored areas, such as healthcare. Currently, blockchain is being implemented mainly as a mechanism to secure Electronic Health Records (EHRs). However, new studies have shown that this technology ca...

The exponential growth in the number of Internet of Things (IoT) devices and applications in recent years can be attributed partly to the emergence of several new IoT startup companies and potential applications. While many of these startups offer significant innovations in the IoT, some of them lack security expertise, resulting in the development...

The Internet of Things (IoT) has experienced significant growth over recent years and Gartner predicts that, by 2020, 21 billion IoT endpoints will be in use. The potential behind widespread usage of small devices capable of collecting, transmitting, or acting upon data has been fueling interest both from industry and academia. Security and forensi...

The world is witnessing the emerging role of Internet of Things (IoT) as a technology that is transforming different industries, global community and its economy. Currently a plethora of interconnected smart devices have been deployed for diverse pervasive applications and services, and billions more are expected to be connected to the Internet in...

Cash, standardized physical tokens that represent economic value, has been a key instrument in the evolution of human civilizations for around 3000 years. However in the last few decades cash has been progressively losing its preeminence in favour of electronic handling of money transactions. The shift to a cashless society, in which physical money...

The dramatic drop in price of computing hardware, coupled with the recent breakthroughs in embedded systems design that enabled the integration of high‐level software and low‐level electronics, have created a paradigm shift in embedded systems development. This has led to the development of different varieties of user‐friendly Internet of Things (I...

The current vision of the Internet of Things (IoT) is to ensure that everything from everywhere is connected to the Internet at all times using Internet Protocol (IP). This idea has the potential of making homes, cities, electric grids, among others, safer, more efficient, and easier to manage. Nevertheless, a number of obstacles still remain to fu...

The Networks of the Future will be made up of much more heterogeneous devices, contributing to a substantially richer and complex ecosystem. In terms of security, and given the fast pace at which computer technology evolves, the hardware and software fragmentation and the maturity of some systems reaching the market, it is foreseeable that the scen...

Trusted computing is a technology that enables computer systems to behave in a given expected way. Achieving that goal happens by arming an isolated piece of hardware with embedded processing, cryptographic capabilities such as encryption key that is kept safe from software layer attacks. The mentioned module is accessible to the rest of the comput...

Cloud computing is a model for providing computing resources as a utility which faces several challenges on management of virtualized resources. Accordingly, virtual machine placement and migration are crucial to achieve multiple and conflicting goals. Regarding the complexity of these tasks and plethora of existing proposals, this work surveys the...

For the last two decades, artificial immune systems have been studied in various fields of knowledge. They were shown to be particularly effective tools at detecting anomalous behavior in the security domain of computer systems. This article introduces the principles of artificial immune systems and surveys several works applying such systems to co...

Cloud computing is an established technology to provide computing resources on demand that currently faces several challenges. Main challenges include management of shared resources, energy consumption, load balancing, resource provisioning and allocation, and fulfilment of service level agreements (SLAs). Due to its inherent complexity, cloud simu...

An Internet of Things (IoT) hardware development platform refers to a self-contained module of interconnected electronic components that include microcontrollers, wireless radio chips, memory and input/output interfaces for prototyping and large-scale production of IoT devices. Competition among different vendors is a major driving force for improv...

The Internet of Things (IoT) is an environment in which ordinary and complex consumer products, buildings, bridges, animals or even people, etc. are embedded with sensors, equipped with a variety of communication technologies and given unique identifiers that can enable them connect to the Internet. This allows them to talk to each other, collect d...

This paper assesses if text possesses fractal properties, namely if several attributes that characterize sentences are self-similar. In order to do that, seven corpora were analyzed using several statistical tools, so as to determine if the empirical sequences for the attributes were Gaussian and self-similar. The Kolmogorov-Smirnov goodness-of-fit...

This paper describes a study for assessing how many free Android games with in-app purchases were susceptible to data manipulation via the backup utility. To perform this study, a data set with more than 800 games available in the Google Play store was defined. The backup utility, provided by the Android OS, was used to backup the app files into a...

There are currently several applications and frameworks to simulate networks, network equipment, applications, services and protocols. These tools play an important role not only in the research and development of new solutions on the computer networking area, but also on other areas of knowledge, because they enable researchers to abstract from th...

Throughout the end of the first half and during the second half of the past century, advances in technology allowed scientists to develop computer systems. In the beginning, mostly between the forties and the sixties, single computers would fill large rooms with electronics that would consume as much power as several hundreds of modern desktop comp...

Self-similarity has been found in many natural and artificial processes since it was first noticed in the fifties. Embedding this property into series of numbers or estimating the self-similarity degree of a time series, given by the Hurst parameter, are not straightforward tasks. Because of that, both subjects have been the recipient of several co...

Nowadays, cybersecurity makes headlines across the media and in companies, blogs, social networks, among other places. The Internet is a wild cyberspace, an arena for commercialization, consumerism, business, and leisure, to name a few activities. Networks, populations, and nations around the world, now interconnected through the Internet, rely on...

Virtualization technology provided cloud computing with the means to rapidly disseminate throughout the industry and achieve the utility computing long-envisioned era. Efforts on this research area have been focused on assuring isolation between co-resident virtual machines to avoid escaping the sandbox, but less attention has been given to the imp...

The degradation of the security of password-based mechanisms, combined with the increasing number of perils on the Internet, is rendering one-factor authentication outdated. This threatens the security of online operations for enterprises and end users, and consequently affects cloud computing solutions. Although cloud computing provides appealing...

Voice over Internet Protocol (VoIP) applications based on peer-to-peer (P2P) communications have been experiencing considerable growth in terms of number of users. To overcome filtering policies or protect the privacy of their users, most of these applications implement mechanisms such as protocol obfuscation or payload encryption that avoid the in...

In the last few years, the appealing features of cloud computing have been fueling the integration of cloud environments in the industry, which has been consequently motivating the research on related technologies by both the industry and the academia. The possibility of paying-as-you-go mixed with an on-demand elastic operation is changing the ent...

Classifying network traffic constitutes one of the most defying research topics nowadays. On the one hand, traffic classification is critical for assuring Quality of Service (QoS), the correct functioning and the security of the networks. On the other hand, the increasing complexity and throughput of networks, added to the problems caused by encryp...

Due to the relevance of self-similarity analysis in several research areas, there is an increased interest in methods to generate realizations of self-similar processes, namely in the ones capable of simulating long-range dependence. This article describes a new algorithm to approximate persistent fractional Brownian motions with a predefined Hurst...

The number and popularity of applications developed over the Peer-to-Peer (P2P) network paradigm has been growing over the last decade, some of which are dedicated to streaming multimedia content. To deceive traffic shaping mechanisms or improve the security of the communications, these applications generate encrypted traffic or resort to several o...

The inclusion of encryption or evasive techniques in popular applications increased the importance of characterizing network traffic based on behavior. This study aims to characterize peer-to-peer (P2P) traffic from the perspective of host computers by focusing on the packet lengths. The article explores the dissimilarities between the lengths of I...

The emergence of new Internet paradigms has changed the common properties of the network data, increas-ing the bandwidth consumption and balancing traffic in both directions. These facts raised important chal-lenges, making it necessary to devise effective solutions for managing network traffic. Since the traditional methods are rather ineffective...

The massive adoption of Peer-to-Peer (P2P) applications brings new challenges for network management. The increase of the bandwidth usage, the shift of the Internet habits of home users and the easiness to share and provide contents is changing the traffic characteristics, and breaking strong assumptions in which network design is based. As a respo...

Traffic modelling and simulation plays an important role in the area of Network Monitoring and Analysis, for it provides practitioners with efficient tools to evaluate the performance of networks and of their elements. This paper focus on the traffic generated by a single source, providing an overview of what was done in the field and studying the...

Traffic monitoring and analysis is of critical importance for managing and designing modern computer networks, and constitutes nowadays a very active research field. In most of their studies, researchers use techniques and tools that follow a statistical approach to obtain a deeper knowledge about the traffic behaviour. Network administrators also...

This paper describes a new algorithm for the generation of pseudo random numbers with approximate self-similar structure. The Simple Self-Similar Sequences Generator (4SG) elaborates on an intuitive approach to obtain a fast and accurate procedure, capable of reproducing series of points exhibiting the property of persistence and anti-persistence....

1 — The transmission medium connecting the Optical Line Terminal (OLT) to Passive Splitter Combiners (PSCs), in Passive Optical Networks (PONs) is shared by all Optical Network Units (ONUs). Therefore, each ONU has to store the data coming from the users, prior to sending it upstream, according to a time division multiple access policy. In this pap...

1 — This paper summarizes a study conducted over traffic generated and received at a network terminal machine. The results it includes may be used to simulate the processes of the interarrival times, of the packet sizes and of the bit count per time unit, at the source level and for several types of telematic applications (namely Voice over IP and...

The growing relevance of wireless communications in our daily lives has been driving the research and development of advanced network architectures to enable the cost-effective support of a large numbers of users at very high data rates. In this context, the FUTON project aims to fulfil the objectives of the so-called 4 th Generation (4G) systems,...

The increasing number of applications offering their services over peer-to-peer (P2P) platforms is changing the properties of the traffic within computer networks. Their massive use raises a few imperative challenges for network administrators and Internet service providers, regarding the quality of service and security of their networks. It such s...

The research on how to use self-similarity for intrusion detection is not unfounded, as the scaling properties seem to partially define the very nature of aggregated traffic, and may become a potential differentiating factor in the presence of an anomaly. This paper explains how network intensive attacks can be injected into simulated traces of tra...

The IEEE 802.3av Task Force is currently working on development of the next-generation, 10 Gbit/s capable Ethernet Passive Optical Network specifications, anticipating to bring a new flavour of PON technology to life by mid 2009.

Most denial of service (DoS) attacks try to exhaust a victim network or server resources by flooding them with a largely exaggerated amount of bogus requests or fake messages. When a given server or network is under a DoS condition, its capability to distinguish good from bogus requests gets severely reduced and the service is refused to some, if n...

We discuss in detail all major security-related issues inherently present in PON systems. Ethernet PON (EPON) type networks have very specific requirements for data- and system-level security, due to combining - for the first time using Ethernet links ?? residential and business customers with different security awareness levels and protection dema...

Ethernet Optical Passive Networks (EPONs), defined as low cost access networks, combine Ethernet technology with an optical fiber infrastructure to deliver voice, video and data services from a Central Office (CO) to end-users Since all data in the downstream is broadcasted, it is susceptible to be eavesdropped by a malicious user, which can use it...