Alvaro Araujo

Alvaro Araujo
Universidad Politécnica de Madrid | UPM · Departmento de Ingeniería Electrónica

Doctor of Engineering

About

74
Publications
17,449
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,030
Citations
Citations since 2016
26 Research Items
669 Citations
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140

Publications

Publications (74)
Article
Full-text available
Herein, we describe the Virtually Enhanced Senses (VES) system, a novel and highly configurable wireless sensor-actuator network conceived as a development and test-bench platform of navigation systems adapted for blind and visually impaired people. It allows to immerse its users into “walkable” purely virtual or mixed environments with simulated s...
Article
The increasingly growth of autonomous end devices applied to Internet of Things (IoT) environments and has led to the development of new microcontrollers with enhanced power modes. An operating system (OS) is usually implemented on top of these resource-constrained devices to enhance applications development and also manage system resources and pow...
Article
Full-text available
The identification of a new generation of adaptive strategies for deep brain stimulation (DBS) will require the development of mixed hardware–software systems for testing and implementing such controllers clinically. Towards this aim, introducing an operating system (OS) that provides high-level features (multitasking, hardware abstraction, and dyn...
Article
Full-text available
Wireless body area networks (WBANs) present unique challenges due to their specific characteristics of mobility and over-the-body radio propagation. A huge amount of factors—both internal and external to the network—affect WBAN channel conditions, so a reliable and comprehensive theoretical model of these communications is unfeasible and impractica...
Article
Full-text available
In this work, we present autonomous active tags. The power sources of these active tags employ energy harvesting techniques, specifically, solar and mechanical techniques. The integration of these techniques, and the storage of the energy obtained with a supercapacitor, converts the active tag into an autonomous device. These tags work in a low pow...
Article
Full-text available
The increasing penetration of wearable and implantable devices necessitates energy-efficient and robust ways of connecting them to each other and to the cloud. However, the wireless channel around the human body poses unique challenges such as a high and variable path-loss caused by frequent changes in the relative node positions as well as the sur...
Article
Full-text available
The continuous increase in the number of mobile and Internet of Things (IoT) devices, as well as in the wireless data traffic they generate, represents an essential challenge in terms of spectral coexistence. As a result, these devices are now expected to make efficient and dynamic use of the spectrum by employing Cognitive Radio (CR) techniques. I...
Article
Full-text available
In this paper, the Virtually Enhanced Senses (VES) System is described. It is an ARCore-based, mixed-reality system meant to assist blind and visually impaired people's navigation. VES operates in indoor and outdoor environments without any previous in-situ installation. It provides users with specific, runtime-configurable stimuli according to the...
Article
Full-text available
The increase in the number of mobile and Internet of Things (IoT) devices, along with the demands of new applications and services, represents an important challenge in terms of spectral coexistence. As a result, these devices are now expected to make an efficient and dynamic use of the spectrum, and to provide processed information instead of simp...
Article
Full-text available
In recent years, wireless sensor networks (WSNs) have experienced a significant growth as a fundamental part of the Internet of Things (IoT). WSNs nodes constitute part of the end-devices present in the IoT, and in many cases location data of these devices is expected by IoT applications. For this reason, many localization algorithms for WSNs have...
Article
Full-text available
Wireless sensor networks (WSNs) have long been established as a suitable technology for gathering and processing information from the environment. However, recent applications and new multimedia sensors have increased the demand for a more adequate management of their quality of service (QoS). The constraints and demands for this QoS management gre...
Article
Full-text available
Wireless sensor networks require time synchronization, which is the coordination of events or actions to make a system operate in unison. In this work, real experiments and a theoretical analysis of the behavior of the clock sources, most used in wireless sensor networks, have been carried out. The experiments have been performed on two real platfo...
Article
Full-text available
The wireless Internet of Things (IoT) family grows without interruption. Every day more applications and wireless devices are available to interconnect and help solve multiple problems in areas such as health, critical infrastructure, industry, etc. Many of the tasks to be performed by the IoT network require time synchronization for their correct...
Article
Full-text available
Over the last decades, the development of navigation devices capable of guiding the blind through indoor and/or outdoor scenarios has remained a challenge. In this context, this paper’s objective is to provide an updated, holistic view of this research, in order to enable developers to exploit the different aspects of its multidisciplinary nature....
Article
Full-text available
The emergence and spread of Internet of Things (IoT) technologies along with the edge computing paradigm has led to an increase in the computational load on sensor end-devices. These devices are now expected to provide high-level information instead of just raw sensor measurements. Therefore, the processing tasks must share the processor time with...
Article
Full-text available
The explosion of the Internet of Things has dramatically increased the data load on networks that cannot indefinitely increment their capacity to support these new services. Edge computing is a viable approach to fuse and process data on sensor platforms so that information can be created locally. However, the integration of complex heterogeneous s...
Article
The use of CAN bus in space applications has increased during the last fifteen years. The need of standardizing not only the physical and link layers but also the higher layers protocol to meet spacecraft specific constraints or requirements, such as bus redundancy management, node monitoring and synchronization, has aroused. Therefore, a Working G...
Article
The expansion of big data and the evolution of Internet of Things (IoT) technologies will play an important role in the feasibility of Smart City initiatives. In this IoT network infrastructure Cognitive Wireless Sensor Networks (WSNs), as a network of nodes that work in a cooperative way to sense the spectrum and control the environment surroundin...
Preprint
The Human Intranet is envisioned as an open, scalable platform that seamlessly integrates an ever-increasing number of sensor, actuation, computation, storage, communication, and energy nodes located on, in, or around the human body, acting in symbiosis with the functions provided by the body itself. The limited amount of available energy and the c...
Article
Full-text available
Wireless Sensor Networks (WSNs) are a growing research area as a large of number portable devices are being developed. This fact makes operating systems (OS) useful to homogenize the development of these devices, to reduce design times, and to provide tools for developing complex applications. This work presents an operating system scheduler for re...
Conference Paper
Full-text available
The loss of efficiency and dependability in wireless communications, caused by the increasing spectrum scarcity problem, is particularly critical for battery-powered devices such as sensor nodes. Cognitive Wireless Sensor Networks (CWSNs) arise in order to mitigate this situation by adding cognitive radio capabilities to them. However, the closed a...
Article
Full-text available
The growth of Device-to-Device (D2D) communications and the extensive use of Wireless Sensor Networks (WSNs) bring new problems such as spectral coexistence and spectrum saturation. Cognitive Radio (CR) appears as a paradigm to solve these problems. The introduction of CR into WSNs as a solution to the spectrum utilization problem could be used not...
Article
Full-text available
Road traffic accidents are one of the main causes of death and disability worldwide. Workers responsible for maintaining and repairing roadways are especially prone to suffer these events, given their exceptional exposure to traffic. Since these actuations usually coexist with regular traffic, an errant driver can easily intrude the work area and p...
Article
Full-text available
A wildland fire is an uncontrolled fire that occurs mainly in forest areas, although it can also invade urban or agricultural areas. Among the main causes of wildfires, human factors, either intentional or accidental, are the most usual ones. The number and impact of forest fires are expected to grow as a consequence of the global warming. In order...
Article
Full-text available
In this paper a common problem in Wireless Sensor Networks (WSN) as is synchronization between distributed measurement nodes is analyzed. This issue becomes more important as information gathered by each node must be combined to form a global information subsequently analyzed. In the case of using WSN for Operational Modal Analysis (OMA) applied to...
Conference Paper
Cognitive Wireless Sensor Networks are an emerging technology with a vast potential to avoid traditional wireless problems such as reliability, interferences and spectrum scarcity in Wireless Sensor Networks. Cognitive Wireless Sensor Networks test-beds are an important tool for future developments, protocol strategy testing and algorithm optimizat...
Article
Full-text available
Wireless sensor networks (WSNs) are one of the most important users of wireless communication technologies in the coming years and some challenges in this area must be addressed for their complete development. Energy consumption and spectrum availability are two of the most severe constraints of WSNs due to their intrinsic nature. The introduction...
Article
Full-text available
Nowadays, Wireless Ad Hoc Sensor Networks (WAHSNs), specially limited in energy and resources, are subject to development constraints and difficulties such as the increasing RF spectrum saturation at the unlicensed bands. Cognitive Wireless Sensor Networks (CWSNs), leaning on a cooperative communication model, develop new strategies to mitigate the...
Article
Full-text available
Cognitive wireless sensor network (CWSN) is a new paradigm, integrating cognitive features in traditional wireless sensor networks (WSNs) to mitigate important problems such as spectrum occupancy. Security in cognitive wireless sensor networks is an important problem since these kinds of networks manage critical applications and data. The specific...
Article
Providing security to the emerging field of ambient intelligence will be difficult if we rely only on existing techniques, given their dynamic and heterogeneous nature. Moreover, security demands of these systems are expected to grow, as many applications will require accurate context modeling. In this work we propose an enhancement to the reputati...
Article
Full-text available
Cognitive Wireless Sensor Network (CWSN) is a new paradigm which integrates cognitive features in traditional Wireless Sensor Networks (WSNs) to mitigate important problems such as spectrum occupancy. Security in Cognitive Wireless Sensor Networks is an important problem because these kinds of networks manage critical applications and data. Moreove...
Article
Full-text available
This paper presents the security evaluation, energy consumption optimization, and spectrum scarcity analysis of artificial noise techniques to increase physical-layer security in Cognitive Wireless Sensor Networks (CWSNs). These techniques introduce noise into the spectrum in order to hide real information. Nevertheless, they directly affect two im...
Article
Full-text available
A cognitive wireless sensor network (CWSN) is an emerging technology with great potential to avoid traditional wireless problems such as reliability. One of the major challenges CWSNs face today is security. A CWSN is a special network which has many constraints compared to a traditional wireless network and many different features compared to a tr...
Conference Paper
This paper presents an artificial noise strategy to increase physical-layer security in Cognitive Wireless Sensor Networks (CWSN). Spectrum sensing, information sharing and collaborative cognitive features are used to avoid eavesdropping attacks. Artificial noise generation is proposed to conceal the secret message to be transmitted. One important...
Article
Full-text available
The area of Human–Machine Interface is growing fast due to its high importance in all technological systems. The basic idea behind designing human–machine interfaces is to enrich the communication with the technology in a natural and easy way. Gesture interfaces are a good example of transparent interfaces. Such interfaces must identify properly th...
Article
Along with the development of cognitive radio networks, designing optimistic security mechanisms is becoming a big challenge. This study proposes a taxonomy of attacks on cognitive radio networks. This will help researches to better understand the security problems and to design more optimistic countermeasures. A new simulation framework for securi...
Article
Structural health monitoring (SHM) systems have excellent potential to improve the regular operation and maintenance of structures. Wireless networks (WNs) have been used to avoid the high cost of traditional generic wired systems. The most important limitation of SHM wireless systems is time-synchronization accuracy, scalability, and reliability....
Conference Paper
This paper considers the problem of secure communication in Wireless Sensor Networks in the presence of non-colluding passive eavesdroppers. Cognitive networks capabilities such as spectrum sensing, share information and collaboration to optimize the communications can be used to avoid attacks. A collaborative jamming technique is proposed to incre...
Conference Paper
The image processing techniques are widely used in many fields, such as security and home automation. With these techniques algorithms are developed for its use in common vision systems (with regular video cameras connected to a computer), consuming too many resources. This paper presents some innovative algorithms to be included in autonomous vis...
Conference Paper
Cognitive Networks appear as solution to avoid AAL scenarios problems like wireless interferences, secure a reliable communications, power consumption or different Quality of Service application needs. In this paper a prototype for Cognitive Wireless Sensor Networks is presented. This node is a hardware solution that will help to overcome problems...
Conference Paper
Mobile user interfaces are moving to new touchscreen technologies setting new barriers for the blind. Many solutions and designs have been proposed but none is complete for the vast heterogeneous variety of devices. In this paper, we present a methodology for developing an accessible-to-blind platform based on the principles that visually impaired...
Article
One of the most important problems of WMNs, that is even preventing them from being used in many sensitive applications, is the lack of security. To ensure security of WMNs, two strategies need to be adopted: embedding security mechanisms into the network protocols, and developing efficient intrusion detection and reaction systems. To date, many se...
Conference Paper
Full-text available
This paper presents the system-level simulation platform we have implemented to design and evaluate the SORU reconfigurable vector coprocessor, aimed at enhancing the security of embedded systems. The simulator interfaces a low-level virtual machine (LLVM) with a SystemC TLM 2.0 model of the rest of the system, and a low-level SystemC model of the...
Conference Paper
Full-text available
In this paper, we suggest handling security in embedded systems with reconfigurability. We propose the use of a reconfigurable coprocessor, called SORU2, to generate non-determinism in the execution of cipher algorithms. This makes side-channel attacks based on statistical analysis much more difficult. The experimental results show at least three o...
Conference Paper
Full-text available
The Sybil attack is one of the most aggressive and evasive attacks in sensor networks that can affect on many aspects of network functioning. Thus, its efficient detection is of highest importance. In order to resolve this issue, in this work we propose to couple reputation systems with agents based on self-organizing map algorithm trained for dete...
Conference Paper
The area of Human-Machine Interface is growing fast due to its high importance in all technological systems. The basic idea behind designing Human-Machine interfaces is to enrich the communication with the technology in a natural and easy way. Gesture interfaces are a good example of transparent interfaces. Such interfaces must perform the action t...
Article
Full-text available
Security of sensor networks is a complicated task, mostly due to the limited resources of sensor units. The first line of defense, i.e. encryption and authentication, is useless if an attacker has entered the system, and it is also vulnerable to side-channel attacks. Thus, a second line of defense, known as Intrusion Detection, must be added in ord...
Conference Paper
The specific nature of routing in sensor networks has made possible new sorts of attacks that can have closer insight and effect on the networks packets, the most important being the packet tampering. Routing attacks on the network level are the first step in tampering with the packets. In this work we propose a solution for detecting and eliminati...
Article
Full-text available
The reliable operation of modern infrastructures depends on computerized systems and Supervisory Control and Data Acquisition (SCADA) systems, which are also based on the data obtained from sensor networks. The inherent limitations of the sensor devices make them extremely vulnerable to cyberwarfare/cyberterrorism attacks. In this paper, we propose...
Conference Paper
Security of sensor networks is a complicated task, mostly due to the limited resources of sensor units. Encryption and authentication are useless if an attacker has entered the system. Thus, a second line of defense known as Intrusion Detection must be added in order to detect and eliminate attacks. In the recent past, various solutions for detecti...
Conference Paper
This paper describes the design and implementation of an object tracking service for indoor environments. First, the wireless indoor location estimation technology is overviewed presenting advantages and disadvantages. Second, the methodology of the study is presented. To estimate the position we use clues inserted by location clue injectors of the...
Conference Paper
Full-text available
Guaranteeing ubiquity and appropriateness of security and monitoring services provision to the users constitutes a priority issue for the authorities. This paper presents an innovative Wireless Personal Area Network architecture that takes advantage of some of the features provided by Intelligent Environments -large number of devices, heterogeneous...
Conference Paper
Full-text available
In this paper we present the design of a low cost system which automatically controls the air conditioning equipments of a home. The sensors and controllers distributed use Zigbee, a protocol for wireless personal area networks, to communicate themselves. The aim of our design is to facilitate the development of complex smart homes applications, em...
Conference Paper
Full-text available
User interaction with the intelligent environment should not require the user to adapt to special conventions or rules. It should be the environment who should adapt to the natural way of users interaction, but the tight resource constraints of the embedded sensors do not allow complex video processing algorithms to be executed in real time. In th...